Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
DSpace
UBCV
Sun, Yuanji
Master of Science - MSc
University of British Columbia
The sources, dispersion, fractionation and fate of two persistent organic contaminants, polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs), were studied in the Strait of Georgia (SoG), by measuring dissolved (< 2.2 μm) and particulate (> 2.2 μm) PCBs and PBDEs concentrations in seawater at various Salish Sea stations from 2013 to 2018. Our results show that the primary sources of particulate PBDEs (pPBDEs) into the southern SoG are effluent particles from Vancouver’s main wastewater treatment plant at Iona Island and sediment resuspension in Burrard Inlet. In contrast, dissolved PBDEs (dPBDEs) in the southern SoG are generated from the desorption of PBDEs from these particles during their transport with the SoG water circulation, leading to high dPBDEs and low pPBDEs concentrations. These findings were supported by changes in particulate PBDEs contribution to the total PBDE concentrations at various stations, as well as the systematic fractionation of PBDE congeners during desorption from sewage particles and re-adsorption onto marine particles. In addition, the SoG estuarine circulation (including tides) leads to substantial temporal variability of dPBDEs concentrations in southern SoG and near Bowen Island. Most PBDEs in the SoG are eventually removed to the sediment through particle scavenging, leaving the less brominated congeners in the dissolved phase to be exported to the Pacific Ocean. The box model simulation demonstrated that the Fraser River is an important PBDE source due to its high flow rate, despite its low dPBDEs concentrations. Low modelled dPBDEs concentrations, compared with what we measured, point to unquantified sources or an increase in the PBDEs Iona discharge. PCBs have been banned for decades, and showed very different behaviour to PBDEs in SoG. Our limited data suggest that industrialized areas in Burrard Inlet are the main sources to SoG, and not the Iona outfall. Furthermore, the PCB homologs’ distribution supports preferential removal of the more hydrophobic dissolved PCBs congeners added to SoG from Burrard Inlet by particle scavenging. Once PCB-contaminated seawater and particles have been in contact long enough in SoG there is a clear increasing trend in particulate to dissolved partitioning with the degree of hydrophobicity of the PCB homologs.
SOURCES, FRACTIONATION AND FATE OF POLYBROMINATED DIPHENYL ETHERS AND POLYCHLORINATED BIPHENYLS IN THE STRAIT OF GEORGIA, CANADA by Yuanji Sun B.Sc., China University of Mining and Technology, 2014 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Oceanography) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) April 2020 © Yuanji Sun, 2020 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, a thesis/dissertation entitled: SOURCES, FRACTIONATION AND FATE OF POLYBROMINATED DIPHENYL ETHERS AND POLYCHLORINATED BIPHENYLS IN THE STRAIT OF GEORGIA, CANADA submitted by Yuanji Sun in partial fulfillment of the requirements for the degree of Master of Science in Oceanography Examining Committee: Dr. Maria T. Maldonado, Department of Earth, Ocean & Atmospheric Sciences Co-supervisor Dr. Roger Francois, Department of Earth, Ocean & Atmospheric Sciences Co-supervisor Dr. Raymond Andersen, Department of Earth, Ocean & Atmospheric Sciences/Chemistry Supervisory Committee Member Dr. Ryan Ziels, Department of Civil Engineering Additional Examiner Additional Supervisory Committee Members: Dr. Paul Schaffer, TRIUMF & Department of Radiology Supervisory Committee Member iii Abstract The sources, dispersion, fractionation and fate of two persistent organic contaminants, polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs), were studied in the Strait of Georgia (SoG), by measuring dissolved (< 2.2 μm) and particulate (> 2.2 μm) PCBs and PBDEs concentrations in seawater at various Salish Sea stations from 2013 to 2018. Our results show that the primary sources of particulate PBDEs (pPBDEs) into the southern SoG are effluent particles from Vancouver’s main wastewater treatment plant at Iona Island and sediment resuspension in Burrard Inlet. In contrast, dissolved PBDEs (dPBDEs) in the southern SoG are generated from the desorption of PBDEs from these particles during their transport with the SoG water circulation, leading to high dPBDEs and low pPBDEs concentrations. These findings were supported by changes in particulate PBDEs contribution to the total PBDE concentrations at various stations, as well as the systematic fractionation of PBDE congeners during desorption from sewage particles and re-adsorption onto marine particles. In addition, the SoG estuarine circulation (including tides) leads to substantial temporal variability of dPBDEs concentrations in southern SoG and near Bowen Island. Most PBDEs in the SoG are eventually removed to the sediment through particle scavenging, leaving the less brominated congeners in the dissolved phase to be exported to the Pacific Ocean. The box model simulation demonstrated that the Fraser River is an important PBDE source due to its high flow rate, despite its low dPBDEs concentrations. Low modelled dPBDEs concentrations, compared with what we measured, point to unquantified sources or an increase in the PBDEs Iona discharge. PCBs have been banned for decades, and showed very different behaviour to PBDEs in SoG. Our limited data suggest that industrialized areas in Burrard Inlet are the main sources to SoG, and not the Iona outfall. Furthermore, the PCB homologs’ distribution supports preferential removal of the more hydrophobic dissolved PCBs congeners added to SoG from Burrard Inlet by particle scavenging. Once PCB-contaminated seawater and particles have been in contact long enough in SoG there is a clear increasing trend in particulate to dissolved partitioning with the degree of hydrophobicity of the PCB homologs. iv Lay Summary Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) are two classes of persistent and toxic organic contaminants with a strong tendency to bioaccumulate and biomagnify in the food chain when discharged in the environment. Samples were collected between 2013 and 2018 to measure their concentration dissolved in seawater and adsorbed on particles at different locations and times in the Strait of Georgia and the Salish Sea. These measurements provide a means of identifying their main sources, and investigating the mechanisms regulating their dispersion and removal. v Preface Sample collection and analysis This project began in 2013. All samples before 2017 were collected by Dr. Roger Francois and Maureen Soon. Dissolved PBDE samples in the Juan de Fuca Strait in 2017 were collected by Robert Izett during the Line P cruise. I collected the rest of the samples between 2017 and 2019. All dissolved and particulate PBDE samples were analyzed by SGS AXYS Analytical Services Ltd. (Sidney, B.C., Canada). The Salish Sea Box Model The Salish Sea Box Model used in Chapter 3 and 4 was published by Wang, Pawlowicz, and Sastri et al. (2019) titled Diurnal and Seasonal Variability of Near-Surface Oxygen in the Strait of Georgia in the Journal of Geophysical Research-Oceans 124(4): 2418-2439, and was optimized by Samuel Stevens. This model was used to investigate the processes that control the concentrations of dissolved PBDEs and PCBs in the Strait of Georgia. I generate all tables and figures in this thesis unless otherwise referenced. Dr. Roger Francois and Dr. Maria Maldonado provided extensive editorial assistance to this thesis. vi Table of Contents Abstract ......................................................................................................................................... iii Lay Summary ............................................................................................................................... iv Preface .............................................................................................................................................v Table of Contents ......................................................................................................................... vi List of Tables ..................................................................................................................................x List of Figures ............................................................................................................................ xvii List of Symbols ......................................................................................................................... xxiii List of Abbreviations ............................................................................................................... xxiv Acknowledgements ....................................................................................................................xxv Dedication ................................................................................................................................. xxvi Chapter 1: Introduction ................................................................................................................1 1.1 Environmental setting ..................................................................................................... 1 1.2 Context of research ......................................................................................................... 2 1.3 Polybrominated biphenyl ethers (PBDEs) ...................................................................... 4 1.4 Polychlorinated biphenyls (PCBs) .................................................................................. 6 1.5 Toxicity of PBDEs and PCBs ......................................................................................... 7 1.6 PBDEs and PCBs in seawater ......................................................................................... 8 1.6 Review of PBDE and PCB contamination in the Strait of Georgia .............................. 10 1.7 Goals of the thesis ......................................................................................................... 11 Chapter 2: Materials and Methods ............................................................................................22 2.1 Sampling sites and sampling platforms ........................................................................ 22 2.2 Sampling methods ......................................................................................................... 27 2.2.1 Dissolved PBDEs and PCBs ..................................................................................... 27 2.2.2 Particulate PBDEs and PCBs .................................................................................... 27 2.3 Analytical methods for PCBs and PBDEs .................................................................... 28 2.4 Procedural blanks .......................................................................................................... 28 2.4.1 Dissolved PBDEs and PCBs ..................................................................................... 28 2.4.2 Particulate PBDEs and PCBs .................................................................................... 29 2.5 The Salish Sea Box Model ............................................................................................ 29 vii Chapter 3: Source, fractionation and fate of PBDEs in the Strait of Georgia .......................31 3.1 Results ........................................................................................................................... 31 3.1.1 Data analysis ............................................................................................................. 31 3.1.2 Laboratory blanks, limits of detection and limits of quantification .......................... 31 3.1.3 Procedural blanks ...................................................................................................... 31 3.1.4 Temporal variability of PBDE concentrations in the Strait of Georgia .................... 33 3.1.4.1 Station S2 .......................................................................................................... 33 3.1.4.2 Station S4-1.5 .................................................................................................... 35 3.1.5 Spatial variability of PBDE concentration in the Salish Sea and the Northeast Pacific Ocean 40 3.1.6 Sources of PBDE to the SoG .................................................................................... 48 3.1.6.1 Iona effluent plume ........................................................................................... 48 3.1.6.2 Burrard Inlet ...................................................................................................... 51 3.1.6.3 Fraser River ....................................................................................................... 53 3.1.7 Dissolved PBDE concentrations in the mixed layer of the Alaskan Gyre in the NE Pacific (Station P26) ............................................................................................................. 55 3.2 Discussion ..................................................................................................................... 55 3.2.1 Working hypotheses.................................................................................................. 55 3.2.2 PBDEs in the effluent of the Iona Island WWTP and their accumulation in SoG sediments............................................................................................................................... 57 3.2.3 Partitioning of PBDE between dissolved and particulate phases in the water column of the SoG ............................................................................................................................. 58 3.2.4 Spatial variation of dissolved and particulate PBDE concentrations in the Salish Sea 60 3.2.5 Depth profiles of dissolved PBDE concentration at the time-series Station S4-1.5 . 64 3.2.5.1 PBDEs input from Metro Vancouver’s primary wastewater treatment plants . 65 3.2.5.2 PBDEs input from the Fraser River and Metro Vancouver’s secondary treatment plants ................................................................................................................. 68 3.2.5.3 PBDEs input from the atmosphere ................................................................... 69 3.2.5.4 Reverse scavenging of dissolved PBDEs in the water column of the SoG ...... 70 viii 3.2.6 Temporal variations in dissolved PBDE concentration at Station S4-1.5 in relation to the water circulation in the SoG ............................................................................................ 71 3.2.6.1 Intermediate water (50 – 200 m) ....................................................................... 72 3.2.6.2 Surface water (0 – 50 m) ................................................................................... 74 3.2.6.3 Deep water (> 200 m) ....................................................................................... 74 3.2.7 Fractionation between congeners in the water column of the SoG .......................... 76 3.2.7.1 Vertical congener fractionation at Station S4-1.5 ............................................. 76 3.2.7.2 Spatial congener fractionation in the Salish Sea ............................................... 82 3.2.8 Mass balance and box model simulation for PBDEs ................................................ 84 Chapter 4: Source, fractionation and fate of PCBs in the Strait of Georgia ........................128 4.1 Results ......................................................................................................................... 128 4.1.1 Data analysis ........................................................................................................... 128 4.1.2 Laboratory blanks, limits of detection and limits of quantification ........................ 128 4.1.3 Procedural blanks .................................................................................................... 128 4.1.4 Temporal variability of PCB concentrations in the Strait of Georgia .................... 130 4.1.5 Spatial variability of PCB concentrations in the Strait of Georgia ......................... 132 4.1.6 Sources of PCBs to the SoG ................................................................................... 138 4.1.6.1 Iona effluent plume ......................................................................................... 138 4.1.6.2 Burrard Inlet .................................................................................................... 141 4.2 Discussion ................................................................................................................... 144 4.2.1 Working hypothesis ................................................................................................ 144 4.2.2 Partitioning of PCBs between dissolved and particulate phases in the water column of the SoG ........................................................................................................................... 145 4.2.3 Spatial variations of dissolved and particulate PCB concentration in the SoG ...... 149 4.2.4 PCB homologs in the Strait of Georgia .................................................................. 151 4.2.4.1 Dissolved PCB homologs ............................................................................... 152 4.2.4.2 Particulate PCB homologs .............................................................................. 154 Chapter 5: Conclusions .............................................................................................................224 5.1 Summary of major findings ........................................................................................ 224 5.1.1 PBDEs ..................................................................................................................... 224 ix 5.1.2 PCBs ....................................................................................................................... 229 5.2 Future studies .............................................................................................................. 230 5.2.1 Atmospheric deposition of PBDEs into the Strait of Georgia ................................ 230 5.2.2 PBDEs’ interaction with particles ........................................................................... 232 5.2.3 Development of passive sampler and field tests ..................................................... 233 Bibliography ...............................................................................................................................235 Appendices ..................................................................................................................................242 Appendix A ............................................................................................................................. 242 A.1 Method .................................................................................................................... 242 A.2 Results ..................................................................................................................... 243 A.3 Conclusions ............................................................................................................. 246 x List of Tables Table 1.1: PCB and PBDE congeners classification. ..................................................................... 4 Table 1.2: Main PBDE congeners (> 0.1% w/w; bold > 1% w/w) in the penta, octa, and deca formulation (La Guardia et al., 2006). ............................................................................................ 6 Table 1.3: Summary of PBDE concentrations (pg/L) in coastal waters worldwide. Rows in bold represent sample collection using passive samplers. “n.d." means not detected. “-” means not reported. “D” and “P” represent dissolved and particulate form, respectively. “Year” represent the year of sampling. Numbers in parentheses are the mean value. ............................................. 13 Table 1.4: Summary of PBDE concentrations (pg/L) in open ocean seawater. Rows in bold represent sample collection using passive samplers. “n.d." means not detected. “-” means not reported. “D” and “P” represent dissolved and particulate form, respectively. “Year” represent the year of sampling. Numbers in parentheses are the mean value. “LOQ” represents limit of quantification. ............................................................................................................................... 15 Table 1.5: Summary of PCB concentrations (pg/L) in coastal waters worldwide. Rows in bold represent sample collection using passive samplers. “n.d." means not detected. “-” means not reported. “D” and “P” represent dissolved and particulate form, respectively. “Year” represent the year of sampling. ..................................................................................................................... 17 Table 1.6: Summary of PCB concentrations (pg/L) in open ocean seawater. Rows in bold represent sample collection using passive samplers. “n.d." means not detected. “-” means not reported. “D” and “P” represent dissolved and particulate form, respectively. “Year” represent the year of sampling. ..................................................................................................................... 19 Table 2.1: Sampling dates and locations, and sample depth and volume to determine the regional distribution of dissolved and particulate PBDE seawater concentration. ..................................... 24 Table 2.2: Volumes of samples collected from Station S4-1.5 (49°15.00’N, 123°40.00’W) and Station S2 (49°17.58'N, 123°22.51'W). ........................................................................................ 24 Table 2.3: Volumes of samples collected from potential input source stations. See Figure 2.1 for a map. ............................................................................................................................................ 26 Table 3.1: Laboratory analysis blanks reported by AXYS for different batches of dissolved (a) and particulate (b) PBDE analysis. Dates are sampling times of samples included in each batch of analysis. Grey cells are data more than 1.5 interquartile range either below the first quartile or xi above the third quartile, which are considered outliers and removed before calculating LoD and LoQ. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX)........................................................................................................................................... 88 Table 3.2: (a) Laboratory procedural blanks for dissolved PBDEs; (b) at sea procedural blank for dissolved PBDEs; (c) laboratory procedural blank for particulate PBDEs. The reported values have been corrected for laboratory analysis blanks of the corresponding sample batch (Table 3.1). Numbers in italics are above LoD but below LoQ. Bold numbers indicate values above LoQ. Empty cells indicate that blank-corrected values were below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). ........................................... 92 Table 3.3: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PBDE congeners in SoG seawater at Station S2. Quantifiable congeners are in bold. Detectable congeners, below LoQ but above LoD, are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). Particulate BDE-209* has been corrected for the procedural blank (Table 3.2c). .......................................... 94 Table 3.4: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PBDE congeners concentrations (pg/L) in SoG seawater at Station S2. Quantifiable congeners are in bold. Detectable congeners, below LoQ but above LoD, are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). BDE-209* has been corrected for the procedural blank (Table 3.2c). ............................ 96 Table 3.5: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PBDE congeners in SoG seawater at Station S4-1.5. Quantifiable congeners are in bold. Detectable congeners, below LoQ but above LoD, are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). Particulate BDE-209* has been corrected for the procedural blank (Table 3.2c). .......................................... 98 xii Table 3.6: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PBDE congeners concentrations (pg/L) in SoG seawater at Station S4-1.5. Quantifiable congeners are in bold. Detectable congeners, below LoQ but above LoD, are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). BDE-209* has been corrected for the procedural blank (Table 3.2c). ......................... 104 Table 3.7: Detectable (> LoD) and quantifiable (>LoQ) dissolved PBDE congeners in the Salish Sea at Stations NG, HS, and JF2 (a) and particulate PBDE congeners at Station NG (b). Quantifiable congeners are in bold. Detectable congeners, below LoQ but above LoD, are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). Particulate BDE-209* has been corrected for the procedural blank (Table 3.2c). .................................................................................................... 110 Table 3.8: Detectable (> LoD) and quantifiable (>LoQ) dissolved PBDE congeners in the Salish Sea at Stations NG, HS, and JF2 (a) and particulate PBDE congeners at Station NG (b). Quantifiable congeners are in bold. Detectable congeners, below LoQ but above LoD, are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). BDE-209* has been corrected for the procedural blank (Table 3.2c). ................................................................................................................................ 112 Table 3.9: Dissolved congener concentration ratios at Station S4-1.5 (Table 3.6a), as well as HS, NG, and JF2 (Table 3.8a). The calculation is based on the average dissolved PBDE concentrations at each station. .................................................................................................... 114 Table 3.10: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PBDE congeners in the Iona effluent plume (S1), Burrard Inlet (S3, S3b), and in the Fraser River (FR). Quantifiable congeners are in bold. Detectable congeners, below LoQ but above LoD, are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). Particulate BDE-209* has been corrected for the procedural blank (Table 3.2c). .................................................................................................... 115 xiii Table 3.11: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PBDE congeners concentrations (pg/L) in the Iona effluent plume (S1), Burrard Inlet (S3, S3b) and in the Fraser River (FR). Quantifiable congeners are in bold. Detectable congeners, below LoQ but above LoD, are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). BDE-209* has been corrected for the procedural blank (Table 3.11c). ............................................................................................ 119 Table 3.12: Particulate-to-total PBDE ratios for concentrations above LoQ in samples collected in the Salish Sea (S2, S3, S3b, S4-1.5, NG and FR). Numbers in italics are above LoD but below LoQ. Bold numbers indicate values above LoQ. Empty cells indicate that blank-corrected values were below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<). Values in the yellow background are considered as good quality...................................................................................................................................................... 123 Table 3.13: Sum of all quantifiable (> LoQ) and detectable (> LoD) particulate and dissolved PBDE concentrations measured at different locations in the Salish Sea. ................................... 126 Table 3.14: Total quantifiable and detectable dissolved PBDE concentrations in the Fraser River (Table 3.11a) and in surface water at Station S4-1.5 (Table 3.6a). ............................................ 126 Table 3.15: Input setting used in the Box Model simulation. ..................................................... 126 Table 3.16: PBDE daily load in the Fraser River. The Fraser River flow rate was measured at Environment and Climate Change Canada Station 08MF005 (Hope) on the day when sample was collected. The PBDE daily load is the sum of dissolved and particulate PBDE load by multiplying the concentration and the flow rate. ........................................................................ 126 Table 3.17: Comparison of PBDE daily load in the Fraser River and Iona effluent. The PBDE daily load in the Fraser River is calculated in Table 3.16 while the Iona effluent daily load is available in Dinn et al. (2012b). .................................................................................................. 127 Table 3.18: Comparison of modelled results and actual results for BDE-47 and BDE-99. ....... 127 Table 4.1: Laboratory analysis blanks reported by AXYS for different batches of dissolved (a) and particulate (b) PCB analysis. Dates are sampling times of samples included in each batch of analysis. Grey cells are data more than 1.5 interquartile range either below the first quartile or above the third quartile, which are considered outliers and removed before calculating LoD and xiv LoQ. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = data not quantifiable (NQ). ........................................................................................................................................... 156 Table 4.2: (a) Laboratory procedural blanks for dissolved PCBs; (b) at sea procedural blank in 2017 for dissolved PCBs (silicon tubing vs. springs closing mechanisms of Niskin bottles); (c) laboratory procedural blank for particulate PCBs in 2013. The reported values have been corrected for laboratory analysis blanks of the corresponding sample batch (Table 4.1). Numbers in italics are above LoD but below LoQ. Bold numbers indicate values above LoQ. Empty cells indicate that blank-corrected values were below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K). .......................................................................................................... 170 Table 4.3: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PCB congeners in SoG seawater at Station S2. Quantifiable congeners are in bold. Detectable congeners below LoQ but above LoD are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K). .................................................................................. 174 Table 4.4: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PCB congeners concentrations (pg/L) in SoG seawater at Station S2. Quantifiable congeners are in bold. Detectable congeners below LoQ but above LoD are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K). ........................................... 180 Table 4.5: PCB concentrations in groups based on halogenation at Station S2. a) dissolved PCBs and b) particulate PCBs. Only quantifiable concentrations were included in the sum (Table 4.3). N/A means no congener is above LoQ. ...................................................................................... 186 Table 4.6: Detectable (>LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PCB congeners in SoG seawater at Station S4-1.5. Quantifiable congeners are in bold. Detectable congeners below LoQ but above LoD are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K). .................................................................................. 187 xv Table 4.7: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PCB congeners concentrations (pg/L) in SoG seawater at Station S4-1.5. Quantifiable congeners are in bold. Detectable congeners below LoQ but above LoD are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K). ........................................... 194 Table 4.8: PCB concentrations in groups based on the halogenation at S4-1.5. a) dissolved PCBs and b) particulate PCBs. Only quantifiable concentrations were included in the sum (Table 4.6). N/A means no congener is above LoQ. ...................................................................................... 202 Table 4.9: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PCB congeners in SoG seawater at Stations S1, S3 and S3b. Quantifiable congeners are in bold. Detectable congeners below LoQ but above LoD are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K). ........................................................... 203 Table 4.10: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PCB congeners concentrations (pg/L) in SoG seawater at Stations S1, S3 and S3b. Quantifiable congeners are in bold. Detectable congeners below LoQ but above LoD are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K). ................... 212 Table 4.11: Dissolved (a) and particulate (b) PCB concentrations in groups based on the halogenation at S1 in December 2013, at S3 in December 2014 and at S3b in December 2015 and August 2016. Only quantifiable concentrations were included in the sum (Table 4.9). N/A means no congener is above LoQ. .............................................................................................. 221 Table 4.12: Total dissolved concentrations, particulate concentration and %particulate of PBDE and PCB, and particulate and dissolved PCB/PBDE ratios in the Iona plume (S1), Burrard Inlet (S3, S3b), near the entrance of Burrard Inlet (S2), and in the middle of the southern SoG (S4-1.5). ............................................................................................................................................. 222 Table 4.13: Particulate congener ratios in S2 (Bowen Island), S3 (Inner Harbor in the Burrard Inlet) and S3b (Central Harbor in the Burrard Inlet). Data in Table 4.5b and Table 4.11b. ....... 222 Table 4.14: Dissolved congener ratios in S2 (Bowen Island), S3 (Inner Harbor in the Burrard Inlet) and S3b(Central Harbor in the Burrard Inlet). Data in Table 4.5a and Table 4.11a. ........ 223 xvi Table 4.15: Total PCB concentrations from the box model under two different scenarios. Experiment 1 added Victoria’s and Vancouver’s effluent input of 2003 reported by Dinn et al. (2012b) to the lower HS and lower SoG boxes, while the Experiment 2 had the same input as Experiment 1 with another 50 g/d of input was added to the upper SoG box. ........................... 223 Table A.1: Iron oxide affinity experiment results. ...................................................................... 244 Table A.2: Large volume experiment results. ............................................................................. 246 xvii List of Figures Figure 1.1: Map of Salish Sea. ........................................................................................................ 1 Figure 1.2: Water circulation in the Strait of Georgia (Pawlowicz et al., 2019). a) Water circulation in the summer, and (b) water circulation in the rest of the year. .................................. 3 Figure 1.3: Chemical structures of selected PCB and PBDE congeners. (a) BDE-47, (b) BDE-99, (c) BDE-153, (d) BDE-209, (e) CB-47, (f) CB-99, (g) CB-153, (h) CB-209. ............................... 5 Figure 2.1: Sampling locations. Station coordinates are reported in Table 2.1. (a) Sampling sites in the Strait of Georgia, (b) Station Papa (P26). S1 is Iona plume. S2 is south of Bowen Island at the mouth of Burrard Inlet. S3 and S3b are Inner Harbor and Central Harbor in the Burrard Inlet, respectively. S4-1.5 is in the southern SoG. FR refers to the Fraser River. NG means northern SoG. HS refers to the Haro Strait. JF2 refers to the Juan de Fuca Strait. P26 is the ocean Station Papa in the NE Pacific Ocean. ...................................................................................................... 23 Figure 2.2: Schematic diagram of the box model used to predict PBDE concentrations (Wang et al., 2019). The Salish Sea is divided into 3 basins: SoG, HS, and JdFS, each of which consisting of an upper and a lower box representing water above and below 50m. Volume fluxes between two boxes are represented by thin arrows, and vertical mixing by thick arrows. Time varying water fluxes between boxes are driven by freshwater discharge from the Fraser River into the upper SoG box and upwelling of Pacific water into the lower JdFS (Qh). ................................... 30 Figure 3.1: Dissolved PBDE congeners concentration at Station S2, 50m measured in December 2013 (blue), October 2014 (red), and December 2015 (yellow). Data in Table 3.4a. .................. 34 Figure 3.2: Average of dissolved PBDE congeners concentrations measured in the water column at Station S4-1.5. The average concentrations were calculated based on dissolved PBDE concentrations at S4-1.5 in all seasons and depths (Table 3.6a). .................................................. 36 Figure 3.3: Temporal variation in the dissolved concentration profiles of some of the main congeners measured at Station S4-1.5. Only numbers above LoD are plotted. Data in Table 3.6a........................................................................................................................................................ 37 Figure 3.4: Depth profiles of select dissolved PBDE congeners at Stn 4-1.5 in May 2017 (a) and Jan 2018 (b). Stars indicate the LoQ for each measurement. Data in Table 3.6a. ........................ 38 Figure 3.5: Seasonal variability of particulate PBDEs measured at Stn 4-1.5. Since all in-situ large volume pumps were deployed at 25 and 150 m in all cruises, the depths in the figure are xviii shifted by 1-2 meters in order to avoid overlap. Only numbers above LoD are plotted. Stars indicate the LoQ for each measurement. Data in Table 3.6b........................................................ 40 Figure 3.6: Concentrations of dissolved PBDEs measured in all stations in the Salish Sea area. The concentration in May 2017 at S4-1.5 is used as a reference. Only numbers above LoD are plotted. Data in Table 3.4a, Table 3.6a, and Table 3.8a. .............................................................. 43 Figure 3.7: Depth profile of dissolved BDE-28+33 in northern Strait of Georgia (Station NG). Only numbers above LoD are plotted. Data in Table 3.8a. .......................................................... 44 Figure 3.8: Average dissolved congener distribution at Station S4-1.5 (Table 3.6a), as well as HS, NG, and JF2 (Table 3.8a)....................................................................................................... 45 Figure 3.9: Concentrations of particulate PBDEs measured in all stations in the Salish Sea area. Only numbers above LoDs are plotted. Data for S4-1.5 in Table 3.6b, and for NG in Table 3.8b........................................................................................................................................................ 47 Figure 3.10: Average particulate PBDE congener concentrations at Station NG (Table 3.8b) vs average particulate PBDE congener concentrations at Station S4-1.5 (Table 3.6b). ................... 48 Figure 3.11: Dissolved PBDE congener concentrations in the effluent plume (Station S1, Table 3.11a) and average concentrations measured at Station S2 (Table 3.4a). ..................................... 49 Figure 3.12: Dissolved (Table 3.11a) and particulate PBDE congener concentrations (Table 3.11b) measured in the effluent plume (Station S1). .................................................................... 50 Figure 3.13: Particulate PBDE concentrations at Station S1 (Iona outfall, Table 3.11b) and average concentration at Station S4-1.5 (Table 3.6b). .................................................................. 51 Figure 3.14: Dissolved and particulate PBDE concentrations at Station S1 (Iona effluent plume) vs Station S3 (Inner Harbor; Burrard Inlet) and S3b (Central Harbor; Burrard Inlet). Data in Table 3.11a and Table 3.11b. ........................................................................................................ 52 Figure 3.15: Dissolved PBDE concentrations in the Fraser River (FR) during high (June 2017) and low (February 2018) water discharge compared to concentrations at S4-1.5 in May 2017 and February 2017. .............................................................................................................................. 54 Figure 3.16: Particulate PBDE concentrations in the Fraser River, during high (June 2017) and low (February 2018) water discharge, compared to the average particulate PBDE concentrations at Station S4-1.5 in all seasons and from all depths. .................................................................... 55 xix Figure 3.17: % fraction of particulate PBDE congeners (a) at Station S4-1.5 in the southern SoG (S4-1.5) , and (b) at Station S1 in the Iona effluent plume close to the diffusers. ........................ 59 Figure 3.18: % fraction of particulate PBDE congeners concentrations over the total at the Inner Harbor (Station S3) and the Central Harbor (Station S3b) in Burrard Inlet. Station 3b was sampled during high tidal current while other samples were not. Data in Table 3.11a and Table 3.11b.............................................................................................................................................. 63 Figure 3.19: Relative congener proportion in suspended particles collected at S3 and sediments from Burrard Inlet (Grant et al., 2011). For suspended particles at S3, the ratio is the particulate congener over total particulate concentrations. For sediment at S3 and S3b, the ratio is the congener concentration at the surficial sediment divided by the total surficial sediment concentrations. .............................................................................................................................. 64 Figure 3.20: (a) Dissolved concentration profiles of the sum of quantifiable congeners (excluding deca- and nona-congeners) at Station S4-1.5 (Table 3.6a). BDE-209 is excluded from the sum because its LoQ is high (Table 3.1) and it is found at the concentration above LoQ only in a few samples, while the nona-brominated congeners are co-varying with BDE-209 and are in part produced by debromination of BDE-209 during analysis (flagged as MAX by AXYS). (b) The dark blue line is the temperature measured at the ONC node located at 170m just south of the outfall (49.0423°N; 123.3171°W); the light blue line is the seasonal temperature variation in the intermediate water entering the SoG at 170m depth; the red line is the seasonal temperature variation in the intermediate water exiting the SoG. Blue circles are the temperature measured during sampling at S4-1.5 at 170m depth. .................................................................................... 67 Figure 3.21: Depth profiles of dissolved PBDEs congener to BDE-47 ratio in May 2017 at S4-1.5. Data in Table 3.6a. ................................................................................................................. 70 Figure 3.22: Total quantifiable dissolved PBDE concentration measured in deep water at Station S4-1.5 (depth of sampling indicating above each bar). BDE-206 to 209 are not included in the concentrations above. .................................................................................................................... 75 Figure 3.23: Bottom current speed (green curves) and seawater densities (red curves) at Ocean Networks Canada’s central node (49.0423°N, 123.3171°W, water depth 300 m; Ocean Networks Canada) in the Strait of Georgia in 2017 (A) and 2018 (B) (Kuang, 2019). Grey areas and arrows represent periods of weak tidal mixing based on tidal predictions and deep water renewal xx seasons, respectively. The positive and negative values of current speed is caused by the direction. ....................................................................................................................................... 75 Figure 3.24: Depth profiles of the concentration of dissolved congeners with increasing degree of bromination measured at S4-1.5 in (a) September 2017 and (b) August 2018. ............................ 77 Figure 3.25: Depth profiles of the concentration ratios of quantifiable dissolved congeners with increasing degree of bromination to BDE-47 measured at S4-1.5 in (a) September 2017, (b) August 2018, and (c) April 2018. Ratios measured at Station S3 (blue diamonds) and S1 (red stars) are also shown. The depth of S1 and S3 are shifted for easier comparison. ....................... 81 Figure 3.26: Dissolved BDE-28+33/BDE-47 concentration ratio (w/w) measured in the Iona effluent plume (S1) and in the Inner Harbor of Burrard Inlet (S3), in the southern SoG (S4-1.5), in the Central Harbor of Burrard Inlet (S3b), and in the northern SoG (NG) and Haro Strait (HS). Data in Table 3.6a, Table 3.8a, and Table 3.11a. ......................................................................... 84 Figure 3.27: Modelled results for BDE-47 and BDE-99 between 2017 and 2019. SoGu and SoGl represent upper and lower Strait of Georgia, respectively. HSu and HSl represent upper and lower Haro Strait, respectively. JdFSu and JdFSl represent upper and lower Juan de Fuca Strait, respectively. .................................................................................................................................. 87 Figure 4.1: Quantifiable PCB congeners measured in the procedural blank conducted in the sample preparation laboratory and using the CCGS John P. Tully’s Niskin bottles with different closing mechanisms (silicon tubing vs. springs closing mechanisms). Data in Table 4.2a. ....... 129 Figure 4.2: Dissolved (a) and particulate (b) PCB homolog concentrations at ~50 m at Station S2, at the mouth of Burrard Inlet, between 2013 and 2015. Data in Table 4.5. ......................... 132 Figure 4.3: Depth profile of total dissolved and particulate PCB concentrations (calculated by summing up the concentrations of all quantifiable congeners) at Station S4-1.5 in August 2018. Data in Table 4.8. ........................................................................................................................ 133 Figure 4.4: Average concentration of dissolved (a) and particulate (b) congeners measured in 2013 – 2015 at Station S2 (blue) and in 2018 at Station S4-1.5 (orange). Data in Table 4.5 and Table 4.8. .................................................................................................................................... 134 Figure 4.5: Average dissolved (a) and particulate (b) PCB homolog concentration at Station S2 (blue, 3 year average) and S4-1.5 (orange, average of depth). Data in Table 4.5 and Table 4.8...................................................................................................................................................... 135 xxi Figure 4.6: Dissolved vs particulate homolog concentrations at Station S4-1.5 at 25 m (a) and 150 m (b) depth. Data in Table 4.8. ............................................................................................ 136 Figure 4.7: Depth profiles of dissolved PCB congeners at S4-1.5 in August 2018. The total concentration of each congener group only includes congeners that are quantifiable (>LoQ). Data in Table 4.8a................................................................................................................................ 137 Figure 4.8: Dissolved (a) and particulate (b) homolog distribution at different depths at Station S4-1.5. Data in Table 4.8. ........................................................................................................... 138 Figure 4.9: Dissolved (a) and particulate (b) congeners concentrations (pg/L) measured in 2013 at Station S1 (orange) and average concentration between 2013 and 2015 at Station S2 (blue). Data in Table 4.5 and Table 4.11. ............................................................................................... 140 Figure 4.10: Dissolved (a) and particulate (b) PCB homolog concentration at Station S2 (blue; average of 3 measurements in December 2013, October 2014 and December 2015) versus S1 (orange; December 2013). Data in Table 4.5 and Table 4.11. .................................................... 141 Figure 4.11: Average dissolved (a) and particulate (b) PCB homolog concentrations (pg/L) at Station S2 (Bowen Island), S3 (Inner Harbor) and S3b (Central Harbor). Data in Table 4.5 and Table 4.11. .................................................................................................................................. 143 Figure 4.12: Dissolved (a) and particulate (b) PCB concentrations (pg/L) quantified at S3b (Central Harbor in the Burrard Inlet) in December 2015 and August 2016. Data in Table 4.11a...................................................................................................................................................... 144 Figure 4.13: % particulate for PCB homologs (a) at southern SoG (S4-1.5 in August 2018), (b) Burrard Inlet (S3: Inner Harbor in December 2014, S3b: Central Harbor in December 2015 and August 2016), (c) Iona effluent plume (S1 in December 2013), (d) Bowen Island (S2 in December 2013, October 2014 and December 2015). Data in Table 4.12. ................................ 148 Figure 4.14: Output results from the box model under different conditions: (a) with the input from Victoria and Vancouver WWTPs added to the lower HS and lower SoG boxes, respectively (Dinn et al., 2012b), and (b) the same inputs from the previous scenario with additional 50 g/d input to the upper SoG box. SoGu and SoGl represent upper and lower Strait of Georgia, respectively. HSu and HSl represent upper and lower Haro Strait, respectively. JdFSu and JdFSl represent upper and lower Juan de Fuca Strait, respectively. ..................................................... 151 xxii Figure 4.15: Dissolved homolog PCB distribution at (a) Station S2 in 2013, (b) Station S1, (c) Station S2 in 2014 and 2015, (d) Station S3. Data in Table 4.5a and Table 4.11a. .................... 152 Figure 4.16: Dissolved PCB homologs distribution at Station 2 in October 2014 and Station 3b in December 2015 and August 2016. Data in Table 4.5a and Table 4.11a..................................... 153 Figure 4.17: Averaged dissolved PCB homologs distribution observed at Station S4-1.5 from all depth except 150 m in August 2018 and S2 in December 2013, October 2014 and December 2015. Data in Table 4.5a and Table 4.8a. ................................................................................... 154 Figure 4.18: Particulate homolog PCB distribution at (a) Station S2 in 2013, (b) Station S1, (c) Station S2 in 2014 and 2015, (d) Station S3. Data in Table 4.5b and Table 4.11b. ................... 155 Figure 4.19: Particulate homolog PCB distribution at (a) Station S2 (average 2013 – 2015), (b) Station S4-1.5. Data in Table 4.5b and Table 4.8b. .................................................................... 155 Figure A.1: The 14C activity changes in SOW and film over time in different materials under different conditions. .................................................................................................................... 245 xxiii List of Symbols Kow n-Octanol/water partition coefficient N2 Nitrogen pg/L Picogram per litre 𝑉𝑉 Volume w/w Weight by weight ∑ Summation °C Celsius xxiv List of Abbreviations B.C. British Columbia CAD Canadian dollar CCGH Canadian Coast Guard Hovercrafts CCGS Canadian Coast Guard Ship dPBDEs Dissolved PBDEs dPCBs Dissolved PCBs dpm Disintegrations per minute FR Fraser River GF/F Glass microfiber filters HRGC/HRMS High resolution gas chromatography/high resolution mass spectrometry HS Haro Strait IDZ Initial dilution zone JF (or JdFS) Juan de Fuca Strait LDPE Low-density polyethylene LoD Limit of detection LoQ Limit of quantification LVP Large volume pump MLD Million litre per day NE North east NG Northern Strait of Georgia ONC Ocean Networks Canada PBDEs (or BDE) Polybrominated diphenyl ethers PCBs (or CB) Polychlorinated biphenyls pPBDEs Particulate PBDEs pPCBs Particulate PCBs QMA Quartz microfiber filters SoG Strait of Georgia SR Silicon rubber stdev Standard deviation Stn Station WWTP Wastewater treatment plant xxv Acknowledgements First and foremost, I would like to express my deepest gratitude to my supervisors, Dr. Maria Maldonado and Dr. Roger Francois, for granting me this great opportunity to continue my studies at UBC. You always listen to me, offer me any kind of support, and give me enough opportunity to try. I enjoy every meeting with you and learn from your insight and pursuit of academic excellence. Besides, I really appreciate your extensive editorial assistance with my thesis. I offer my enduring gratitude to my committee members, Dr. Raymond Andersen and Dr. Paul Schaffer, for their input into my research. My sincere thanks also go to Dr. Rich Pawlowicz who provides me with insight into the water circulation in the Salish Sea. I wish to extend my special thanks to Maureen Soon for sharing her expertise in laboratory and fieldwork, listening to my frustrations, and offer any kind help to me. I wish to acknowledge the help from my lab and office mates for accompanying me during this journey, such as Cheng Kuang, Iselle Flores Ruiz, Samuel Stevens, Jian Guo, Robert Izett, Ross McCulloch, and Anwar Al-Qattan. The fieldwork needs cooperation, especially for my samples which need large volumes of seawater. I want to thank everyone who helped me during cruises, especially Chris Payne and Larysa Pakhomova, all volunteers, as well as captains and crew members of the CCGH Siyay and Moytel, and CCGS Vector and John P. Tully, who made all the fieldwork possible. Last but not least, I would like to thank Metro Vancouver and IsoSiM program for their kind funding support, and special thanks are owed to my parents for their generous love and trust. xxvi Dedication To my parents and friends 1 Chapter 1: Introduction 1.1 Environmental setting The Salish Sea includes the Strait of Georgia, Puget Sound, Strait of Juan de Fuca and Haro Strait (Figure 1.1). The Strait of Georgia (SoG), one of the largest marine waterways in western North America, is a semi-enclosed basin lying between Vancouver and Vancouver Island in British Columbia, Canada with an area of 200 km × 30 km and a depth up to 400 m. The Fraser River is the main source of fresh water, accounting for ~80% of the total run-off. The remainder is supplied by smaller rivers draining directly into the SoG (Pawlowicz et al., 2007). The Fraser River reaches its peak flow during the freshet in early summer, as a result of snow melt in the large drainage basin of the river, while the local rivers follow the seasonal variations in local precipitation, which is higher in winter. The flow of fresh water drives an estuarine circulation with relatively fresh surface water flowing out towards the Pacific and more saline water entering the Salish Sea at depth via the Juan de Fuca Strait (Figure 1.2). Figure 1.1: Map of Salish Sea. 2 The water column of the SoG can be subdivided into three layers: the surface layer down to 50 m; the intermediate layer between 50 and 200 m depth, and the deep layer below 200 m (Figure 1.2). The surface layer is highly stratified due to the large source of fresh water, which is mostly discharged in the southern SoG by the Fraser River. The intermediate water originates from Haro Strait where strong tidal currents vigorously mix the entire water column. Haro Strait water is produced by mixing of incoming Pacific water and outflowing surface SoG water in a ratio of about 40:60. The intermediate water resides in the SoG for about 160 days before upwelling into the surface layer and exiting into the Pacific via Haro and Juan de Fuca Strait (Figure 1.2). Deep water is renewed intermittently between late spring or early summer and early fall. Renewal occurs as a result of stronger coastal upwelling in summer, which brings denser water into the Salish Sea. During neap tides, when mixing in Haro Strait is reduced, denser Pacific water spills over Haro Strait and displaces deep water in the SoG. The salinity of deep water decreases through winter as a result of diapycnal mixing, reducing its density, so that it can be displaced by the incoming deep water over next summer. In the early stages of deep water renewal, the incoming water has relatively lower nutrient and higher oxygen concentration compared to the deep water cascading down the deep basins of the SoG in late summer or early fall (Masson, 2002). 1.2 Context of research This study is a contribution to a project funded under the Georgia Strait Ambient Monitoring Program, which is an environmental research program initiated by the Greater Vancouver Sewerage and Drainage District of Metro Vancouver to investigate the influence of liquid waste discharged in the Strait of Georgia and to establish environmental baselines. The project combines physical, chemical and biological aspects with the following goals: (1) Establish the spatial patterns of water circulation in the SoG surface, intermediate and deep water and their seasonal and interannual variability; (2) Establish how circulation affects the timing of the spring phytoplankton bloom and the regional distribution of primary production and the dispersal of lithogenic and biogenic particles added by rivers and biological production; 3 (3) Understand the sources, sinks and dispersion and ultimate fate of two persistent organic pollutants (PCBs and PBDEs), as well as one toxic (silver), and two potentially toxic metals (copper and cadmium). This thesis focusses on the sources and dispersion of PCBs and PBDEs discharged in the SoG by documenting the spatial and temporal variability of dissolved and particulate PCBs and PBDEs in the Salish Sea. Figure 1.2: Water circulation in the Strait of Georgia (Pawlowicz et al., 2019). a) Water circulation in the summer, and (b) water circulation in the rest of the year. 4 1.3 Polybrominated biphenyl ethers (PBDEs) Over the last several decades, PBDEs have been widely used as flame retardant in many products. Because they are not chemically bonded, they easily leach from the treated products and a large fraction ends up in the wastewater stream and is discharged into the environment (Alaee et al., 2003). Indeed, PBDEs have been found everywhere, from rivers and lakes (e.g. S. J. Chen et al., 2006; Vives et al., 2007), to remote areas such as the Arctic (Moller et al., 2011b), and even in the sediments of the deepest ocean trenches (Dasgupta et al., 2018). They are found in water (Oros et al., 2005; Sacks et al., 2012), sediment (Johannessen et al., 2008b) and the atmosphere (Xie et al., 2011). In addition, they strongly bioaccumulate up the food chain, resulting in high concentrations in higher trophic levels, including in human blood and milk (Kajiwara et al., 2004; She et al., 2007). PBDEs have the chemical formula C12H(10−x)BrxO (where x =1, 2, …, 10), resulting in up to 209 congeners differentiated by the number and position of bromine atoms on the two phenyl moieties. PBDEs are classified into 10 different groups (or homologs) depending on the number of Br atoms (Table 1.1). The structures of some of the most common congeners are shown in Figure 1.3. Table 1.1: PCB and PBDE congeners classification. Congener number Number of Br/Cl atoms Group name 1~3 1 Mono-BDE/CB 4~15 2 Di-BDE/CB 16~39 3 Tri-BDE/CB 40~81 4 Tetra-BDE/CB 82~127 5 Penta-BDE/CB 128~169 6 Hexa-BDE/CB 170~193 7 Hepta-BDE/CB 194~205 8 Octa-BDE/CB 206~208 9 Nona-BDE/CB 209 10 Deca-BDE/CB 5 (a) (b) (c) (d) (e) (f) (g) (h) Figure 1.3: Chemical structures of selected PCB and PBDE congeners. (a) BDE-47, (b) BDE-99, (c) BDE-153, (d) BDE-209, (e) CB-47, (f) CB-99, (g) CB-153, (h) CB-209. The volatility of the PBDE congeners decreases and their hydrophobicity increases with increasing degree of bromination, so that the least brominated congeners have longer transport ranges in the vapour phase in the atmosphere, or in the dissolved phase in water, while the more brominated congeners are more rapidly adsorbed on particles and removed into soils and sediments. For instance, it has been estimated that the atmospheric travel distance of PBDE congeners ranges from 480 km for BDE-209 to 2,227 km for BDE-15 (Wania et al., 2003). PBDEs also have relatively long half-lives in the environment, and are considered “Persistent Organic Pollutants” (half-life > 60 days in seawater; > 180 days in marine sediments; UNEP, 2017). For instance, PBDEs’ average half-life of 4.6 ± 3.7 years has been estimated in European soils with low PBDE loading based on the data obtained between 1998 and 2008 (Schuster et al., 2011). The lack of measurable degradation of BDE-209 in soil incubated with 0.5% sludge over a period of 160 days (Nyholm et al., 2010) is also consistent with the very slow rate of PBDE degradation in soil. In addition, since PBDEs decompose initially by debromination, which produces less brominated congeners which can potentially be more toxic than the initial congener, their environmental impact can last much longer than their reported half-life. Due to their hydrophobic and lipotropic properties, PBDEs enter food webs through bioconcentration (adsorption from water) or bioaccumulation (uptake from food), and their concentration increases up the food chain (biomagnification) (e.g. Gustafsson et al., 1999; Streets 6 et al., 2006). The “Bioconcentration Factor” [BCF; ratio of the congener concentrations in organisms (in the case of PBDEs, normalized to their lipid content) relative to their concentrations in seawater] depends on both the lipotropic properties and the molecular size of the congeners, so that BCF increases from mono- to penta-brominated PBDEs with their hydrophobicity, but decrease from penta- to deca-brominated PBDEs with their molecular size (Mizukawa et al., 2009). Phytoplankton adsorbs dissolved PBDEs onto the cell surface and eventually absorb them into the cell (Deng et al., 2016; Frouin et al., 2013). Animals at higher trophic levels acquire these contaminants through diet and directly from the environment through their skin, lungs or gills (Cullon et al., 2005; Magnusson et al., 2007; Magnusson et al., 2010). PBDEs can cause both acute and chronic toxicity to animals and humans, impacting reproduction, energy metabolism, neuroplasticity, and thyroid function (Kodavanti et al., 2015). PBDEs production started in the 1970s in three commercial formulations, known as the penta-, octa-, and deca formulation. The deca formulation has been the most widely used and consisted almost exclusively of BDE-209, while the most abundant congeners in the penta formulation were BDE-47, BDE-99 and BDE-100, with lesser amount of BDE-153 and BDE-154. BDE-183, BDE-196, BDE-197 and BDE-203 were the main congeners in the octa formulation (Table 1.2). Their production reached a maximum (ca. 85 ktons/y) around the year 2000 and declined sharply thereafter following a ban on the penta- and octa-formulation in 2004, and on the deca formulation in 2014. Nonetheless, release to the environment is expected to continue for another 30 years from in-use and waste stocks (Abbasi et al., 2019). Table 1.2: Main PBDE congeners (> 0.1% w/w; bold > 1% w/w) in the penta, octa, and deca formulation (La Guardia et al., 2006). Formulation Main PBDE congeners Penta 28/33, 47, 49, 66/42, 85, 99, 100, 138, 139, 140, 153, 154, 155 Octa 138, 144, 153, 154, 171, 180, 183, 196, 197, -201, 203, 206, 207, 208, 209 Deca 196, 206, 207, 209 1.4 Polychlorinated biphenyls (PCBs) Similar to PBDEs, PCBs are also a group of persistent organic contaminants consisting of 209 congeners whose volatility decreases and hydrophobicity increases with the degree of 7 halogenation. They are described by the chemical formula C12H(10−x)Clx (where x =1, 2, …, 10), where (x) is the number of chlorine atoms bound to the two phenyl moieties (Figure 1.3; Table 1.1). Unlike PBDEs, however, which are dominated by a few congeners, PCBs are distributed among many different congeners. They have been mass-produced from the 1930s to the 1970s, when they reached a maximum production of ca. 40 ktons/y, before being banned on account of their toxicity. Their use thus pre-dates that of PBDEs. They were applied in multiple industrial applications, such as in large volume electrical transformers and capacitors, hydraulic fluids, adhesives, and inks. Their release was mostly accidental and occurred during their manufacture, use, and disposal. They are considered “legacy” contaminants, which continue to be leached from contaminated sites and recycled within the environments 5 decades after ending their production. Since they have low volatility, release to the atmosphere mostly occurs during waste incineration (Agrell et al., 2004). However, once air-born, PCBs can travel long distances to be eventually deposited into very remote environments, although long-range atmospheric transport decreases in the order of tetra-CBs>hexa-CBs>hepta-CBs>deca-CB (Gouin et al., 2004). PCBs have also long half-lives in the environment. For instance, the average half-life of PCB congeners in soil has been estimated at >3 years (Schuster et al., 2011). Because of their lipophilic properties, they are also prone to bioaccumulation in living organisms and biomagnification up the food chains, resulting in the highest levels in predatory marine mammals (Cullon et al., 2005). In general, the bioaccumulation factor increases with the increasing level of chlorination (Gustafsson et al., 1999). These organic pollutants, similarly to PBDEs, disrupt the function of the endocrine system in mammals, with repercussions for development, reproduction and immune protection. 1.5 Toxicity of PBDEs and PCBs PBDEs can cause both acute toxicity and chronic toxicity to animals. For example, zebrafish under low BDE-71 dose exposure exhibited a decrease in total cumulative egg production and egg protein content (Yu et al., 2015). Similarly, a low dose of BDE-99 results in permanent effects on rats’ reproductive system, by reducing sperm and spermatid counts (Kuriyama et al., 2005). PBDEs can also influence energy metabolism, neuroplasticity, visual 8 discrimination learning and thyroid disruption in rats (Dufault et al., 2005; Gong et al., 2018; Kodavanti et al., 2015). Human beings are facing similar health risks, especially sensitive population such as pregnant women and developing infant (e.g. Rovira et al., 2019; Vuong et al., 2018). Similar toxicity effects have been found for PCBs. For example, PCBs can cause embryotoxic and teratogenic effects in birds (e.g. American kestrels; Hoffman et al., 1996), as well as neuro-developmental toxicity in human infants (Winneke et al., 2002). 1.6 PBDEs and PCBs in seawater Fewer studies have focused on measuring dissolved and particulate PBDEs and PCBs in seawater because of the large volumes of water required for their analysis (Table 1.3, Table 1.4, Table 1.5, Table 1.6, and references therein). As expected, PBDE concentrations are higher and more variable in coastal zones due to greater proximity to point sources. For instance, total particulate and dissolved PBDE concentrations exceeding 1,000 pg/L were found in Jiaozhou (Ju et al., 2016) and Sanggou Bay (Ge et al., 2018), while dissolved PBDE concentrations < 10 pg/L have been reported in Arctic estuaries (Carroll et al., 2008). Within a coastal area, seawater PBDE concentrations can also span several orders of magnitude depending on sampling locations (Ge et al., 2018; Oros et al., 2005), reflecting dilution or removal from point sources, or sediment resuspension, particularly in shallow water. In contrast, total PBDE concentrations in the open ocean are generally a few pg/L (Table 1.4). Particulate PBDEs are generally collected by filtration using in-situ large volume pumps and large membrane filters (QMA filters, nominal pore size of 2.2 µm; 140 mm diameter), while dissolved PBDEs are adsorbed from the filtrate onto XAD columns (e.g. Moller et al., 2012; Salvado et al., 2016). Occasionally, passive samplers have also been used to measure dissolved PBDEs (Perron et al., 2013; Sacks et al., 2012; Sun et al., 2016). In the latter case, only truly dissolved PBDE (< 0.02 µm) can diffuse into the passive samplers and the concentrations estimated from these devices can be orders of magnitude lower than measured by the other method, indicating that most of the “dissolved” PBDEs measured by filtration and column adsorption consist largely of PBDEs in colloidal form, associated with fine particles, or complexed with dissolved organic matter (Sacks et al., 2012). 9 The PBDE congeners measured in seawater are either those found in the highest concentration in the three banned commercial formulations (Table 1.2) or their debromination products (e.g. BDE-47 and 71: Ge et al., 2018; Salvado et al., 2016). BDE-209 is often the dominant congener in seawater (Ge et al., 2018; Moller et al., 2012; Moller et al., 2011a), except in some rare cases (e.g. Salvado et al., 2016). BDE-209 cannot be quantified with passive sampler because of the exceedingly long time required for diffusion into the sampler matrix. In the Arctic Ocean, the higher concentration of BDE-209 in surface waters, and higher concentrations of less brominated congeners and congeners not commercially produced (BDE-71) in deep water suggests debromination of BDE-209 in deep water (Salvado et al., 2016). PBDEs in seawater are influenced by multiple physical, chemical and biological processes such as mixing, advection, adsorption on and desorption from particles, biological uptake, and sediment resuspension. They reach the coastal zone either through rivers and run-off, effluent discharges, or atmospheric transport. For instance, effluents from wastewater treatment plants are the main source to San Francisco Estuary (Oros et al., 2005). In contrast, river input and land run-off are the primary sources in the Kara Sea, Narragansett Bay and the North Sea (Carroll et al., 2008; Moller et al., 2012; Zhao et al., 2018). As legacy contaminants that have been recycled in the environment for several decades, PCBs have seawater concentrations which tend to be less spatially variable. For instance, it has been reported that dissolved PCB concentrations in the Atlantic Ocean do not vary with longitude, due to intense mixing by currents, but the effect of river input, especially from the Amazon River, and dispersion by the Gulf Stream can still be distinguished (Lohmann et al., 2012). In Fram Strait, total PCB concentrations are low, but still contribute to a significant net northward transport of PCBs into the Arctic Ocean (Ma et al., 2018). PCBs profiles measured in Fram Strait and in the Tropical Atlantic indicate that PCBs, whose production peaked 50 years ago, have been transported to the deep ocean by the Atlantic meridional overturning circulation. In contrast, the more recently produced PBDEs have not yet reached the deep ocean (Sun et al., 2016). This preliminary study suggests that particle scavenging is not the primary process bringing PCBs to deep ocean water. As PCBs in the environment comprise a much larger number of congeners than PBDEs (which are largely dominated by a few congeners), estimating total PCB concentrations is less 10 precise because it requires the addition of many individual congeners found at very low concentrations. To facilitate monitoring the spatial and temporal evolution of PCB concentrations in the marine environment, the International Council for the Exploration of the Sea (ICES) selected seven congeners (CB-28, -52, -101, -118, -138, -153, -180), on account of their relative abundance in commercial mixtures and their encompassing chlorination range, as well as the fact that these congeners were included in the OSPAR (Oslo/Paris convention for the protection of the Marine Environment of the NE Atlantic) Coordinated Environmental Monitoring Programme (CEMP) 1998. In addition, several PCB congeners (non-ortho CB-77, -81, -126, -169) are of particular concern because of their stereochemical similarity with dioxin, lending to similar toxic effects on organisms. Although they are typically found at a much lower concentration than the ortho-congeners, the routine analysis of three of them (CB-77, -126, -169) is recommended. 1.6 Review of PBDE and PCB contamination in the Strait of Georgia Several studies have focused on PBDE and PCB concentrations in the sediments (Grant et al., 2011; Johannessen et al., 2008b) and upper trophic levels (e.g. killer whale and seal) (Cullon et al., 2005; Ross et al., 2013) of the Strait of Georgia, but measurements in seawater have been limited to a few samples collected in 2003 in Boundary Passage, Rosario Strait and Johnstone Strait (Figure 1.1). Dissolved PBDE concentrations were found to be very low at these locations, and close to their limit of quantification, while total dissolved PCB concentrations were 2-30 times higher (Frouin et al., 2013). Accumulation rates of PBDEs and PCBs in SoG sediments have been used to assess the impact of wastewater treatment plant discharge on the PBDE mass balance of the SoG (Dinn et al., 2012a; Dinn et al., 2012b; Johannessen et al., 2015). These studies concluded that while wastewater treatment plants could only contribute ~5% of the PCBs accumulating in SoG sediments, they could account for up to 60% of the PBDEs (Johannessen et al., 2015). PBDEs accumulating in SoG sediments are dominated by BDE-209 and their concentration in sediments is directly related to the distance from major point sources, such as Iona WWTP and Vancouver Harbor (Grant et al., 2011; Johannessen et al., 2008b). In contrast, PCBs do not have clear point sources and their concentrations in sediments is controlled by sediment accumulation and mixing 11 rates (Johannessen et al., 2008b), although PCB distribution patterns still point to historical point sources in urban areas (Grant et al., 2011). Downcore sediment profiles measured in the early 2000’s show that PCB accumulation had been decreasing in previous decades, while PBDE accumulation had been increasing (Johannessen et al., 2008a; Johannessen et al., 2008b) . The latter is expected to plateau and decrease, as PBDEs production ceases. Although PCB concentrations in SoG sediment are below the Sediment Quality Guidelines of the Canadian Council of Ministers of the Environment, these guidelines have been shown to fall short of adequately protecting the health of wildlife and human consumers (Arblaster et al., 2015). Both PBDEs and PCBs have been detected in many marine animals living in the Salish Sea (Alava et al., 2012; Elliott et al., 2009; Ross et al., 2013). In harbour seals, PCB concentrations have declined by ~81% between 1984 and 2009, reflecting the ban on their production in the 1970s. In contrast, PBDE concentrations in harbor seals in Puget Sound increased between 1984 and 2003, but started to decrease between 2003 and 2009 (Ross et al., 2013). The average PBDE concentration was only about half the PCBs concentration (Ross et al., 2013). For sea lions, the dominant PBDE congener is BDE-47 and ~80% of sea lions in the SoG have PCBs over the toxicity threshold (Alava et al., 2012). For benthic invertebrates, PCB uptake appears to be mostly controlled by the chemical properties of the congeners, while PBDEs uptake is strongly linked to the sediment properties (Dinn et al., 2012b). 1.7 Goals of the thesis The goals of this thesis are (1) to identify the sources of PCBs and PBDEs to the Strait of Georgia, (2) to document the dispersion of PCBs and PBDEs in the Salish Sea, with a focus on the Strait of Georgia, and (3) to determine the ultimate fate of PCBs and PBDEs discharged in the SoG, and distinguish between the importance of scavenging by settling particles, burial in sediments, and the export to the Pacific Ocean. In order to meet these goals, dissolved and particulate PCBs and PBDEs concentration profiles were measured in the Salish Sea to address the following questions. (1) How are PCBs and PBDEs in the water column of the Strait of Georgia partitioned between dissolved (< 2.2 μm) and particulate (> 2.2 μm) concentrations and what are their dominant congeners? 12 (2) Can the distribution of PCBs and PBDEs in the Salish Sea identify their sources? (3) What are the seasonal and spatial variabilities of PCBs and PBDEs concentrations in the water column of SoG? What is the respective importance of circulation, adsorption on and desorption from particles, and particle scavenging on the observed temporal and spatial variability in the concentration of PBDE and PCBs in the SoG? (4) What is the fraction of PCB and PBDE discharged in the SoG which is buried in SoG sediment versus exported to the Pacific Ocean by currents? PCBs have been banned for five decades, and their concentrations are slowly decreasing (Johannessen et al., 2008b). In contrast, PBDEs have only been banned recently and they have been produced in large quantities in recent decades. Thus, this thesis focuses mostly on PBDEs, whose concentrations in the environment are expected to overtake PCBs concentrations. 13 Table 1.3: Summary of PBDE concentrations (pg/L) in coastal waters worldwide. Rows in bold represent sample collection using passive samplers. “n.d." means not detected. “-” means not reported. “D” and “P” represent dissolved and particulate form, respectively. “Year” represent the year of sampling. Numbers in parentheses are the mean value. Location Year # Type BDE-17 BDE-28 BDE-47 BDE-66 BDE-71 BDE-85 BDE-99 BDE-100 BDE-138 BDE-153 BDE-154 BDE-183 BDE-190 BDE-209 Total Reference Sanggou Bay, China 2015 D - - - - - - - - - - - - - 20-2,130 40-2,200 a Ge et al. (2018) P - - - - - - - - - - - - - n.d.-2,890 480-6,150 a Ge et al. (2018) Jiaozhou Bay, China 2015 D - - - - - - - - - - - - - 70-1,230 90-1,350 a Ju et al. (2016) P - - - - - - - - - - - - - 520-4,390 1,170-5,450 a Ju et al. (2016) Pearl River Estuary, China 2005-2006 D - - - - - - - - - - - - - n.d.-537 2.15-127 b M. Y. Chen et al. (2011) P - - - - - - - - - - - - - 0.27-5,690 6.2-77.6 b M. Y. Chen et al. (2011) New York/New Jersey Harbor, U.S. 2000-2001 D - - (44) - - - (35) (5.5) - - - - - (52) (96) a Zarnadze et al. (2008) P - - (43) - - - (36) (5.4) - - - - - (535) (627) a Zarnadze et al. (2008) San Francisco Estuary, U.S. 2002 D 0.2-36.5 0.9-17.4 j 17.7- 179.5 0.8-7.9 - 0.4-2.3 11.7-90.7 2.7-20.7 n.d.-1.4 i 2.2-10.3 1.2-9.3 0.8-26.9 n.d.-1.1 n.d.-191 0.2-512.9 c Oros et al. (2005) Izmir Bay, Turkey 2005 D - 1.4-2.7 9.5-40 - - - 14-57 3.4-11 - 2.5-8.2 1.6-5.4 - - 54-89 87 -212 d Cetin et al. (2007) P - 1.5-3.1 11-34 - - - 16-53 3.8-11 - 2.7-8.3 1.8-5.7 - - 157-443 271-479 d Cetin et al. (2007) Rosario Strait, Canada 2005-2006 D - - - - - - - - - - - - - - 6.5-18.1 e Frouin et al. (2013) P - - - - - - - - - - - - - - 10.9-14.9 f Frouin et al. (2013) Boundary Passage, Canada 2005-2006 D - - - - - - - - - - - - - - 6.8-14.4 e Frouin et al. (2013) P - - - - - - - - - - - - - - 10.3-10.6 f Frouin et al. (2013) 14 Location Year # Type BDE-17 BDE-28 BDE-47 BDE-66 BDE-71 BDE-85 BDE-99 BDE-100 BDE-138 BDE-153 BDE-154 BDE-183 BDE-190 BDE-209 Total Reference Johnstone Strait, Canada 2005 D - - - - - - - - - - - - - - 2.2 -2.5 e Frouin et al. (2013) P - - - - - - - - - - - - - - 3.1 -8.4 f Frouin et al. (2013) East of Greenland Coast 2005 D+P 0.01 0.05-0.37 0.22-0.23 n.d.-0.01 0.01-0.06 0.01 0.12-0.24 0.02-0.03 0.01-0.02 0.03-0.10 0.02-0.08 n.d.-0.03 n.d.-0.03 0.34 0.9 -1.5 a Salvado et al. (2016) Hong Kong Coast 2005 D - n.d.-32.2 n.d.-27.5 - - - n.d.-2.6 n.d.-5.3 - n.d. - n.d.-3.2 - n.d.-Trace n.d.-62.3 g Wurl et al. (2006) P - n.d.-22.1 n.d.-22.4 - - - n.d. n.d.-3.8 - n.d. - n.d. - n.d. n.d.-32.5 g Wurl et al. (2006) Newport Harbor, U.S. - D 39.8±5.3 - n.d. - - - n.d. n.d. - - - - - - 39.8 ±5.3 h Perron et al. (2013) Greenwich Bay, U.S. - D 10.2±5.1 - 1.94±0.14 - - - n.d. 15.1±0.59 - - - - - - 33.0 ±4.2 h Perron et al. (2013) Mt. Hope Bay, U.S. - D 12.7±1.6 - 11.9±8.1 - - - n.d. n.d. - - - - - - 24.7 ±8.7 h Perron et al. (2013) Bristol Harbor, U.S. - D 8.67±0.82 - 4.38±0.24 - - - n.d. n.d. - - - - - - 13.1 ±0.98 h Perron et al. (2013) California Coast, U.S. 2009-2010 D - n.d.-5.6 0.31-9.4 n.d.-0.5 - - 0.06-2.6 0.02-0.6 - n.d.-0.05 n.d.-0.043 n.d. - - - Alvarez et al. (2014) Santa Monica Bay, U.S. 2011 D - - 3.1-100 - - - 0.34-47 n.d.-17 - - - - - - - Joyce et al. (2015) Los Angeles Harbor, U.S. 2011 D - - 11-34 - - - 1.3-8.4 0.74-4.0 - - - - - - - Joyce et al. (2015) Narragansett Bay, U.S. 2009 D - n.d.-0.62 0.18-2.3 - - - 0.02-0.89 0.004-0.14 - n.d.-0.028 n.d.-0.007 n.d. - - - Sacks et al. (2012) Note: a: includes BDE-17, 28, 47, 66, 71, 85, 99, 100, 138, 153, 154, 183, 190, and 209. b: includes BDE-28, 47, 66, 99, 100, 153, 154, and 183. BDE-209 is not included. c: includes BDE-17, 28/33, 47, 66, 85, 99, 100, 138/166, 153, 154, 183, 190, 206, 207, 208, and 209. d: includes BDE-28, 47, 99, 100, 153, 154, and 209. e: includes 16 PBDE congeners. Detailed congeners are not mentioned in the reference. f: includes 14 PBDE congeners. Detailed congeners are not mentioned in the reference. g: includes BDE-28, 47, 99, 100, 153, 156, 183, and 209. h: includes BDE-17, 47, 71, 99 and 100. i: BDE-138/166. j: BDE-28/33. 15 Table 1.4: Summary of PBDE concentrations (pg/L) in open ocean seawater. Rows in bold represent sample collection using passive samplers. “n.d." means not detected. “-” means not reported. “D” and “P” represent dissolved and particulate form, respectively. “Year” represent the year of sampling. Numbers in parentheses are the mean value. “LOQ” represents limit of quantification. Location Year # Type BDE-17 BDE-28 BDE-47 BDE-66 BDE-71 BDE-85 BDE-99 BDE-100 BDE-138 BDE-153 BDE-154 BDE-183 BDE-190 BDE-209 Total Reference Norwegian Sea 2001 D+P 0.02 0.07-0.09 0.17-0.40 n.d.-0.01 n.d. n.d.-0.01 0.09-0.22 0.02-0.04 n.d.-0.01 n.d.-0.03 n.d.-0.01 n.d.-0.01 n.d.-0.01 1.6-10.4 1.9-11.2 a Salvado et al. (2016) North Sea, Germany 2010 D - - n.d.-1.1 - - - n.d.-1.1 n.d.-0.18 - n.d.-0.10 - n.d.-0.20 - n.d.-1.2 n.d.-3.8 b Moller et al. (2012) P - - n.d.-0.11 - - - n.d.-0.19 n.d. - n.d.-0.30 - n.d. - n.d.-8.1 n.d.-8.7 b Moller et al. (2012) Barents Sea 2001 D+P n.d.-0.02 0.02-0.06 0.11-0.19 n.d.-0.01 n.d.-0.01 n.d.-0.01 0.11-0.20 n.d.-0.04 0.01 0.01-0.07 n.d.-0.07 n.d. n.d. 0.6-7.8 0.9-8.3 a Salvado et al. (2016) Laptev Sea 2008 D+P n.d.-0.01 0.06-0.09 n.d.-1.02 n.d. n.d.-0.003 0.01-0.06 n.d.-1.75 n.d.-0.29 0.003-0.01 0.01-0.31 n.d.-0.15 n.d.-0.01 n.d.-0.01 0.6-5.5 1.0-6.2 a Salvado et al. (2016) Beaufort Sea 2005 D+P n.d.-0.03 0.04-0.10 0.36-0.51 n.d. 0.01 0.01-0.02 0.84-0.88 0.09-0.14 0.01 0.13-0.31 0.02-0.06 0.02 0.02 2.1-4.1 3.9-5.9 a Salvado et al. (2016) Shelf of Northern Canadian Arctic Archipelago 2005 D+P 0.07 0.11 1.16 0.02 n.d. 0.08 2.25 0.38 0.01 0.35 0.13 0.03 0.03 0.4 5 a Salvado et al. (2016) Central Arctic Ocean Basin 2001 D+P n.d.-0.02 n.d.-0.06 n.d.-0.32 n.d. n.d.-0.01 n.d.-0.02 n.d.-0.07 0.005-0.04 n.d.-0.01 n.d.-0.02 n.d.-0.02 n.d. n.d. 0.2-3.4 0.2-4.2 a Salvado et al. (2016) Chukchi Sea 2005 D+P 0.01-0.09 0.02-0.39 n.d.-0.41 n.d. 0.01-0.02 0.01-0.03 n.d.-0.68 0.03-0.09 0.004-0.01 0.04-0.18 n.d.-0.04 0.01-0.02 0.01-0.02 0.1-1.5 1.1-2.4 a Salvado et al. (2016) Kara Sea 2008 D+P n.d. 0.02 0.16 n.d. n.d. 0.005 0.27 0.05 n.d. 0.05 0.02 n.d. n.d. 0.8 1.3 a Salvado et al. (2016) East Siberian Sea 2008 D+P n.d.-0.02 0.01-0.11 n.d.-0.33 n.d. n.d.-0.004 n.d.-0.02 n.d.-0.26 n.d.-0.06 n.d.-0.03 0.01-0.16 n.d.-0.02 n.d.-0.01 n.d.-0.01 0.6-0.9 0.9-1.0 a Salvado et al. (2016) Arctic ice 2007 D - - n.d.-2.3 - - - n.d.-1.6 - - - - - - - - Lacorte et al. (2009) Atlantic and Southern Ocean 2008 D - - 0.02-1.05 - - n.d.-0.03 0.01-0.53 n.d.-0.11 - n.d.-0.05 n.d.-0.11 n.d.-0.075 - - - Xie et al. (2011) P - - n.d.-0.10 - - n.d. n.d.-0.10 n.d.-0.023 - n.d.-0.029 n.d. n.d.-0.066 - - - Xie et al. (2011) 16 Location Year # Type BDE-17 BDE-28 BDE-47 BDE-66 BDE-71 BDE-85 BDE-99 BDE-100 BDE-138 BDE-153 BDE-154 BDE-183 BDE-190 BDE-209 Total Reference East Greenland Sea 2009 D - n.d. n.d.-0.06 n.d.-0.11 - n.d.-0.04 n.d.-0.04 n.d.-0.02 - n.d.-0.009 n.d.-0.005 n.d.-0.05 - n.d.-0.37 - Moller et al. (2011b) P - n.d. n.d.-0.08 n.d. - n.d.-0.01 n.d. n.d.-0.008 - n.d.-0.007 n.d.-0.001 n.d.-0.009 - n.d.-0.11 - Moller et al. (2011b) Tropical Atlantic 2012-2013 D - - 0.13-1.4 - - - 0.007-1.6 0.003-0.35 - - - - - - - Sun et al. (2016) 2009 D - 0.01-0.12 0.21-0.77 <LOQ - 0.001-0.003 0.03-0.10 0.01-0.02 - n.d.-0.002 n.d.-0.001 n.d. - n.d.-0.004 0.26-0.99 Lohmann et al. (2013) North Atlantic 2012-2013 D - - - - - - 0.08-1.3 0.004-0.03 - - - - - - - Sun et al. (2016) Notes: a: includes BDE-17, 28, 71, 47, 66, 100, 85, 99, 138, 153, 154, 183, 190, and 209. b: includes BDE-47, -99, -100, -153, -183, and -209. 17 Table 1.5: Summary of PCB concentrations (pg/L) in coastal waters worldwide. Rows in bold represent sample collection using passive samplers. “n.d." means not detected. “-” means not reported. “D” and “P” represent dissolved and particulate form, respectively. “Year” represent the year of sampling. Location Year # Type CB-28 CB-52 CB-101 CB-118 CB-138 CB-153 CB-180 Total Reference Banyuls-sur-Mer Coast, France 2001-2002 D 4-252 61-1,052 20-607 i 7-807 18-1,036 1-756 1-152 447-15,765 a Garcia-Flor et al. (2005) P 1-50 1-454 4-199 i 4-290 5-215 4-173 3-89 95-4,616 a Garcia-Flor et al. (2005) Pearl River Estuary, China 2005-2006 D - - - - - - - 18-7,180 b M. Y. Chen et al. (2011) P - - - - - - - 21.3-14,700 b M. Y. Chen et al. (2011) Barcelona Coast, Spain 2001-2002 D 1-293 n.d.-1,207 6-523 i n.d.-459 n.d.-505 n.d.-370 n.d.-25 120-9,356 a Garcia-Flor et al. (2005) P n.d.-41.8 1-823 5-617 i 5-614 6-470 5-451 n.d.-366 138-9,621 a Garcia-Flor et al. (2005) Izmir Bay, Turkey 2005 D 8-17 8-11 2-6 6-12 3 3-4 3-4 132-205 c Odabasi et al. (2008) P 8-18 6-10 5-10 9-13 5.4-7 5-7 3-4 118-181 c Odabasi et al. (2008) Johnstone Strait, Canada 2005 D - - - - - - - 65.1-70.1 d Frouin et al. (2013) P - - - - - - - 1.7-2.5 e Frouin et al. (2013) Rosario Strait, Canada 2005-2006 D - - - - - - - 25.2-38.6 d Frouin et al. (2013) P - - - - - - - 8.5-12.9 e Frouin et al. (2013) Boundary Passage, Canada 2005-2006 D - - - - - - - 27.8-34.4 d Frouin et al. (2013) P - - - - - - - 4.8-8.9 e Frouin et al. (2013) Singapore Coast 2003-2004 D - - - - - - - 0.27-1.8 (Wurl et al., 2005) Western Mediterranean Coast 2002 D n.d.-4 h - n.d.-18 n.d.-12 n.d. n.d. n.d. n.d.-65 f Marrucci et al. (2013) 18 Location Year # Type CB-28 CB-52 CB-101 CB-118 CB-138 CB-153 CB-180 Total Reference California Coast, U.S. 2009-2010 D n.d.-17 n.d.-94 n.d.-55.3 n.d.-2.4 n.d.-55.3 0.68-3.3 g n.d.-0.72 - Alvarez et al. (2014) Santa Monica Bay, U.S. 2011 D n.d. n.d.-24 n.d.-9.3 n.d.-12 n.d.-65 n.d.-27 g - - Joyce et al. (2015) Los Angeles Harbor, U.S. 2011 D n.d.-28 25-45 6.1-9.6 5.5-8.5 7.5-14 3.8-6.3 g - - Joyce et al. (2015) Notes: a: includes CB- 17, 18, 28, 31, 33, 44, 49, 52, 70, 74, 82, 87, 95, 99, 101, 105, 110, 118, 128, 132, 138, 149, 151, 153, 158, 169, 170, 171, 177, 180, 183, 187, 191, 194, 195, 199/201, 205, 206, 208, and 209. b: includes CB-4, 8, 15, 16, 17, 18, 22, 28, 37, 56, 66, and 70. c: includes CB-17, 18, 28, 31, 33, 44, 49, 52, 70, 74, 82, 87, 95, 99, 101, 105, 110, 118, 128, 132, 138, 149, 151, 153, 158, 177, 180, 183, and 187. d: includes 86 PCB congeners. Detailed congeners are not mentioned in the reference. e: includes 63 PCB congeners. Detailed congeners are not mentioned in the reference. f: includes CB-77, 126, 169, 81, 105, 114, 118, 123, 156, 157, 167, 189, 28, 52, 95, 101, 99, 110, 151, 149, 146, 153, 138, 187, 183, 177, 180, 170, 128, 44, 31, and 18. g: CB-153/168. h: CB-28/31. i: CB-99/101. 19 Table 1.6: Summary of PCB concentrations (pg/L) in open ocean seawater. Rows in bold represent sample collection using passive samplers. “n.d." means not detected. “-” means not reported. “D” and “P” represent dissolved and particulate form, respectively. “Year” represent the year of sampling. Location Year # Type CB-28 CB-52 CB-101 CB-118 CB-138 CB-153 CB-180 Total Reference Arctic ice 2007 D n.d.-30 ** - n.d.-28 n.d.-98 - - - - Lacorte et al. (2009) North Pacific 1989-1990 D - - - - - - - 9.1-63 a Iwata et al. (1993) Bay of Bengal and Arabian Sea 1989-1990 D - - - - - - - 13-46 a Iwata et al. (1993) Eastern Indian Ocean 1989-1990 D - - - - - - - 9.7-42 a Iwata et al. (1993) South China Sea 1989-1990 D - - - - - - - 9.6-33 a Iwata et al. (1993) Mediterranean 1989-1990 D - - - - - - - 24-30 a Iwata et al. (1993) North Atlantic 1989-1990 D - - - - - - - 21-29 a Iwata et al. (1993) Northern North Pacific 1989-1990 D - - - - - - - 7.4-24 a Iwata et al. (1993) Java Sea 1989-1990 D - - - - - - - 22 a Iwata et al. (1993) Strait of Malacca 1989-1990 D - - - - - - - 20 a Iwata et al. (1993) Celebes Sea 1989-1990 D - - - - - - - 20 a Iwata et al. (1993) East China Sea 1989-1990 D - - - - - - - 14-19 a Iwata et al. (1993) Caribbean Sea 1989-1990 D - - - - - - - 18 a Iwata et al. (1993) Gulf of Alaska 1989-1990 D - - - - - - - 8.8-17 a Iwata et al. (1993) Gulf of Mexico 1989-1990 D - - - - - - - 16 a Iwata et al. (1993) Bering Sea 1989-1990 D - - - - - - - 11-12 a Iwata et al. (1993) 20 Location Year # Type CB-28 CB-52 CB-101 CB-118 CB-138 CB-153 CB-180 Total Reference Southern Ocean 1989-1990 D - - - - - - - 4.6-10 a Iwata et al. (1993) Chukchi Sea 1989-1990 D - - - - - - - 6.6-9.3 a Iwata et al. (1993) Red Sea 1989-1990 D - - - - - - - 9.3 a Iwata et al. (1993) North Atlantic 2005 D 0.12-0.41 0.10-0.36 0.05-0.42 c n.d.-0.13 0.05-0.22 0.02-0.20 n.d.-0.06 0.35-1.67 b Gioia et al. (2008) South Atlantic 2005 D 0.06-0.19 0.12-0.10 n.d.-0.11 c n.d.-0.06 n.d.-0.06 n.d.-0.06 n.d.-0.04 0.07-0.69 b Gioia et al. (2008) Part of North Sea & Norwegian Sea 2004 D 0.14- 0.43 d 0.10-0.26 n.d.-0.06 n.d.-0.10 n.d.-0.06 - - - Gioia et al. (2008) P - - - - n.d.-0.25 n.d.-0.39 - - Gioia et al. (2008) Greenland Sea 2004 D 0.14- 0.22 d 0.09-0.14 0.03-0.04 n.d.-0.05 n.d.-0.07 - - - Gioia et al. (2008) P - - - - n.d.-0.14 n.d.-0.07 - - Gioia et al. (2008) Arctic Ocean 2004 D 0.14- 0.36 d 0.12-0.37 n.d.-0.05 n.d.-0.03 n.d.-0.02 - - - Gioia et al. (2008) P - - - - n.d.-0.05 n.d.-0.05 - - Gioia et al. (2008) Marginal ice zone in the northern Barents Sea 2001 D 0.03-0.23 0.02-0.22 - - - n.d.-0.10 n.d.-0.02 e - Sobek et al. (2006) North Pole 2001 D 0.05 0.08 - - - 0.01 0.001 e - Sobek et al. (2006) Tropical Atlantic 2012-2013 D 0.01-0.63 0.07-1.3 1.3-3.3 0.78-1.6 1.4-2.4 2.2-3.5 0.20-0.34 - Sun et al. (2016) North Atlantic 2012-2013 D 0.12-0.35 0.06-0.26 0.03-0.15 0.0001-0.10 - 0.004-0.17 - - Sun et al. (2016) Canary Basin 2003-2005 D n.d. n.d. n.d.-0.71 n.d.-0.81 n.d.-1.1 n.d.-0.84 n.d.-0.29 - Booij et al. (2014) Irminger Sea 2003-2005 D n.d. n.d.-1.3 0.19-0.58 0.12-0.54 n.d.-0.35 0.10-0.46 n.d.-0.05 - Booij et al. (2014) Mozambique Channel 2003-2005 D n.d. n.d. n.d. n.d. n.d. n.d. n.d. - Booij et al. (2014) 21 Notes: a: includes all congeners measured. A detailed list of congeners is not provided in the reference. b: includes CB-28, 52, 101, 118, 138, 153, and 180. c: BDE-90/101. d: CB-28/31. e: CB-180/193. 22 Chapter 2: Materials and Methods 2.1 Sampling sites and sampling platforms The water column was sampled between October 5, 2013 and August 27, 2018 to document the regional variability of dissolved and particulate PBDE concentration in the Salish Sea (Stations JF2, HS, S2, S4-1.5, NG; Figure 2.1a, Table 2.1) and in the Pacific Ocean (Station P26; Figure 2.1b, Table 2.1), as well as to assess the temporal variability in the Strait of Georgia (Stations S2 and S4-1.5; Figure 2.1a, Table 2.2). In the earlier stages of this project, time series sampling was initiated at a station located south of Bowen Island (S2). The station was sampled three times before moving the time-series station to the more centrally located Station S4-1.5 (Table 2.2). This move resulted from changing our sampling platform from the small research vessel R/V Strickland to the Canadian Coast Guard Hovercrafts (CCGH) Siyay and Moytel, which allowed us to sample a location farther removed from the Iona outfall and the Fraser River plume. PBDE concentrations were measured 6 times at S4-1.5 over the course of 18 months (Table 2.2). Samples were also collected from suspected point sources, such as the Iona effluent plume (S1), Burrard Inlet (S3 and S3b), and the Fraser River, downstream of the Annacis WWTP discharge point (FR) (Figure 2.1a, Table 2.3). Sampling for PCBs was less extensive and was limited to Stations S1, S2, S3, S3b and S4-1.5. Dissolved and particulate PCB concentrations were only measured once at Station 4-1.5 (Table 2.2). Different sampling platforms were used in the course of this project. The time series samples at Stn 4-1.5 were sampled from the CCGH Siyay and Moytel. JF2 and P26 were sampled from the Canadian Coast Guard Ship (CCGS) John P. Tully, while NG and HS were sampled during a dedicated cruise on the CCGS Vector. In addition, the Fraser River samples (FR) and the Inner Harbor of Burrard Inlet (Stn 3) were collected using a small boat (UBC’s Kraken), while Stations S1, S2, and S3b were sampled from the R/V Strickland. 23 Figure 2.1: Sampling locations. Station coordinates are reported in Table 2.1. (a) Sampling sites in the Strait of Georgia, (b) Station Papa (P26). S1 is Iona plume. S2 is south of Bowen Island at the mouth of Burrard Inlet. S3 and S3b are Inner Harbor and Central Harbor in the Burrard Inlet, respectively. S4-1.5 is in the southern SoG. FR refers to the Fraser River. NG means northern SoG. HS refers to the Haro Strait. JF2 refers to the Juan de Fuca Strait. P26 is the ocean Station Papa in the NE Pacific Ocean. (a) (b) 24 Table 2.1: Sampling dates and locations, and sample depth and volume to determine the regional distribution of dissolved and particulate PBDE seawater concentration. Stn # Date Latitude Longitude Depth (m) Volume (dPBDEs, L) Volume (pPBDEs, L) P26 20-Sep-2018 50°00.00’N 145°00.00’W 25 462.3 * - JF2 18-Jun-2017 48°18.00’N 124°00.00’W 20 106.9 - JF2 18-Jun-2017 48°18.00’N 124°00.00’W 160 116.0 - JF2 27-Sep-2018 48°18.00’N 124°00.00’W 20 461.1 * - JF2 27-Sep-2018 48°18.00’N 124°00.00’W 160 459.3 * - HS 27-Aug-2018 48°37.80’N 123°14.60’W Composite 453.4 ** - S4-1.5 See Table 2.2 S2 See Table 2.2 NG 25-Aug-2018 49°43.60’N 124°40.80’W 0 157.0 - NG 24-Aug-2018 49°43.60’N 124°40.80’W 25 - 1436.6 NG 25-Aug-2018 49°43.60’N 124°40.80’W 25 117.2 - NG 25-Aug-2018 49°43.60’N 124°40.80’W 50 115.5 - NG 24-Aug-2018 49°43.60’N 124°40.80’W 75 119.1 - NG 24-Aug-2018 49°43.60’N 124°40.80’W 150 114.1 1026.5 NG 24-Aug-2018 49°43.60’N 124°40.80’W 330 149.2 - Note: * 24 Niskin bottles were triggered to collect a large volume sample. ** 77.7 L from 20 m, 78.9 L from 55 m, 72.1 L from 90 m, 80.2 L from 125 m, 71.1 L from 160 m, and 73.5 L from 195 m depth were combined to produce a composite sample. Table 2.2: Volumes of samples collected from Station S4-1.5 (49°15.00’N, 123°40.00’W) and Station S2 (49°17.58'N, 123°22.51'W). Station # Date Depth (m) Volume (dPBDEs, L) Volume (pPBDEs, L) Volume (dPCBs, L) Volume (pPCBs, L) 2 11-Dec-2013 55 - 561.8 - 561.8 2 11-Dec-2013 45-55 111.0 - 111.0 - 2 02-Oct-2014 48-52 - 711.3 - 711.3 2 02-Oct-2014 50 100.6 - 100.6 - 2 15-Dec-2015 55 - 163.1 - 163.1 2 15-Dec-2015 55-65 125.53 - 125.5 - 4-1.5 14-Feb-2017 5-7 127.7 - - - 4-1.5 14-Feb-2017 50-60 116.8 - - - 4-1.5 09-May-2017 2 129.07 - - - 4-1.5 09-May-2017 25 - 373.4 - - 4-1.5 09-May-2017 27 130.44 - - - 4-1.5 09-May-2017 44 115.14 - - - 4-1.5 09-May-2017 64 119.73 - - - 4-1.5 09-May-2017 143 114.66 - - - 4-1.5 09-May-2017 150 - 222.7 - - 4-1.5 09-May-2017 286 116.00 - - - 4-1.5 12-Sep-2017 2 124.14 - - - 4-1.5 15-Sep-2017 25 - 399.2 - - 25 Station # Date Depth (m) Volume (dPBDEs, L) Volume (pPBDEs, L) Volume (dPCBs, L) Volume (pPCBs, L) 4-1.5 12-Sep-2017 31 128.68 - - - 4-1.5 12-Sep-2017 57 119.72 - - - 4-1.5 15-Sep-2017 71 124.72 - - - 4-1.5 15-Sep-2017 145 118.47 - - - 4-1.5 15-Sep-2017 150 - 198.7 - - 4-1.5 15-Sep-2017 305 126.47 - - - 4-1.5 15-Jan-2018 25 - 1104.4 - - 4-1.5 22-Jan-2018 26 128.54 - - - 4-1.5 22-Jan-2018 73 126.81 - - - 4-1.5 22-Jan-2018 147 128.19 - - - 4-1.5 22-Jan-2018 150 - 747.8 - - 4-1.5 25-Jan-2018 342 313.73 - - - 4-1.5 12-Apr-2018 2 124.66 - - - 4-1.5 12-Apr-2018 24 126.68 - - - 4-1.5 12-Apr-2018 25 - 944.5 - - 4-1.5 12-Apr-2018 59 126.48 - - - 4-1.5 17-Apr-2018 73 126.90 - - - 4-1.5 7-Apr-2018 150 - 824.2 - - 4-1.5 17-Apr-2018 160 127.31 - - - 4-1.5 17-Apr-2018 307 127.31 - - - 4-1.5 10-Aug-2018 4 120.91 - 120.9 - 4-1.5 10-Aug-2018 25 - 473.9 - 473.9 4-1.5 10-Aug-2018 26 124.48 - 124.5 - 4-1.5 10-Aug-2018 54 122.74 - 122.7 - 4-1.5 07-Aug-2018 70 123.52 - 123.5 - 4-1.5 07-Aug-2018 147 83.00 - 83.0 - 4-1.5 07-Aug-2018 150 - 644.5 - 644.5 4-1.5 07-Aug-2018 294 122.76 - 122.8 - 26 Table 2.3: Volumes of samples collected from potential input source stations. See Figure 2.1 for a map. Stn # Date Latitude Longitude Depth (m) Volume (dPBDEs, L) Volume (pPBDEs, L) Volume (dPCBs, L) Volume (pPCBs, L) 1 05-Oct-2013 49°12.32'N 123°18.00'W 55 - 745.0 - - 1 11-Dec-2013 49°12.32'N 123°18.00'W 53-60 110.1 - 110.1 - 3 05-Dec-2014 49°17.88'N 123°04.91'W 5-25 207.6 187.6 207.6 187.6 3b 16-Dec-2015 49°17.75'N 123°00.26'W 20-30 - 172.0 - 172.0 3b 16-Dec-2015 49°17.75'N 123°00.26'W 15-35 117.0 - 117.0 - 3b 31-Aug-2016 49°17.75'N 123°00.26'W 18-20 - 191.9 - 191.9 3b 31-Aug-2016 49°17.75'N 123°00.26'W 15-24 101.5 - 101.5 - FR 23-Jun-2017 49°08.66’N 123°02.65’W 5 109.8 109.8 - - FR 13-Feb-2018 N/A N/A 3 368.8 368.8 - - 27 2.2 Sampling methods 2.2.1 Dissolved PBDEs and PCBs Relatively large sample volumes are required to measure dissolved PBDEs and PCBs in seawater. In most instances, 100-120 L were collected (Table 2.1, Table 2.2, Table 2.3) by deploying ten 12 L Go-Flo bottles at targeted depths, which were drained at sea into acetone-cleaned metal kegs using an acetone-cleaned metal funnel. The kegs were then transported to the laboratory and stored at 4°C before being processed within 48 hours. The kegs were pressurized using N2 gas to force seawater through a pre-combusted QMA filter (nominal porosity of 2.2 µm; 140 mm diameter), to remove suspended particles, and a XAD-2 column―provided by SGS AXYS Analytical Services Ltd. (Sidney, B.C., Canada) ― at a flow rate between 400-800 mL/min to adsorb dissolved PBDEs and PCBs. The QMA filters were not analyzed because the volumes filtered (ca. 100 L) were too small for particulate PBDE and PCB analyses. In several instances, larger volumes (ca. 450 L; Station HS, JF2 and P26; Figure 2.1) were processed to enable the quantification of lower concentrations. At Station JF2 in September 2018, 24 × 12 L Niskin bottles were used to collect large samples at 20 m and 160 m (Table 2.1). In August 2018, a composite sample was taken from Haro Strait by combining 70 – 80 L of seawater taken at 6 depths over the entire water column (Table 2.1). In September 2018, 24 × 12 L Niskin bottles were used to collect large samples in the mixed layer at Station P26 (Figure 2.1b; Table 2.1). 2.2.2 Particulate PBDEs and PCBs Particulate samples were collected by deploying in-situ large volume pumps (McLane LVPs). One or two pumps were deployed at each depth and several hundred liters of seawater was filtered in-situ over one or two hours. Sample depths and volumes are reported in Table 2.1, Table 2.2 and Table 2.3. To separate large fast sinking particles and small suspended particles, a 53 μm nylon mesh was placed above a pre-combusted QMA filter (nominal porosity of 2.2 µm; 140 mm diameter) to collect particles between 53 and 2.2 µm. All filters were carefully rinsed with a mist of Milli-Q water to remove sea salt prior to storage. Mesh filters were placed in acetone-cleaned glass petri dishes, while QMA filters were folded and placed in pre-combusted aluminum envelopes before being stored in coolers with ice packs. In the laboratory, QMA filters 28 were unfolded using acetone-cleaned metal forceps and air-dried for 1 day, and was stored of room temperature -20 oC for PBDE and PCB analyses. 2.3 Analytical methods for PCBs and PBDEs PBDEs and PCBs were analyzed in the same sample. Due to analytical cost (~CAD 900 per sample for PBDEs or PCBs, ~CAD 1700 for both PBDEs and PCBs), PCBs were not measured on all samples (Table 2.1, Table 2.2, Table 2.3). Both XAD-2 samples and QMA filter samples were analyzed using high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS), and following AXYS internal method “SGS AXYS METHOD MLA-010”. Samples were spiked with 13C-labeled surrogate standard solution, extracted, followed by silica and alumina chromatography purification. Sample volumes were further reduced to 50 μL and spiked with 2 μL recovery standard, containing 13C-labeled analogues, before analysis. 2.4 Procedural blanks 2.4.1 Dissolved PBDEs and PCBs Four procedural blanks were conducted for dissolved PBDEs and three for dissolved PCBs. The first procedural blank for dissolved PBDEs an PCBs was conducted in the laboratory where seawater samples were processed. The procedural blanks for dissolved PBDEs and PCBs were prepared by adding 4 L of contaminant-free water―provided by SGS AXYS Analytical Services Ltd. (Sidney, B.C., Canada) ―into an acetone-cleaned metal keg. Water was then processed identically to our samples (see Section 2.2.1). The samples at Station P26 and JF2 from the CCGS John P. Tully were collected using the ship’s rosette. Since we used two types of Niskin bottles, with either silicone tubing or a metal springs, separate procedural blanks were prepared for each type of bottle. One Niskin bottle of each type was selected and rinsed with contaminant-free water obtained from AXYS. Contaminant-free water was then added into the Niskin bottles (10.8 L for the bottle with silicone tubing and 11.2 L for the one with metal tubing) and allowed to soak for 1 hour. The soaking water was then drained into acetone-cleaned metal kegs and carried to the laboratory where all samples were then processed as indicated above. 29 A fourth procedural blank was conducted on the deck of the CCGS Vector during the Salish Sea survey cruise in August 2018. During the CCGS Vector, we used the same Go-Flo bottles as in the cruises on board of the R/V Strickland and CCGH Siyay, but they were deployed with the ship’s rosette. Bottles were rinsed by lowering and closing the rosette at 200m depth at 48°59.980'N, 123°25.519'W in the SoG (near Galiano Island). This was deemed sufficiently deep and far away (~22 km) from the Iona discharge point to avoid contact with the effluent plume. The bottles were then emptied on deck and closed overnight, before conducting the procedural blank. The procedural blank was prepared by adding ~ 6 L of contaminant-free water, obtained from AXYS, into the rinsed Go-Flo bottles and soaked for 1 hour. The soaking water was then drained into acetone-cleaned metal kegs and processed on deck as described above. 2.4.2 Particulate PBDEs and PCBs The procedural blanks of particulate PBDEs were obtained by soaking the filter holder of the in-situ LVPs in contaminant-free water for 2 hours, which is the typical pumping time during in-situ LVPs filtrations. The soaking water was then added to a 3.5 L AXYS contaminant-free water and filtered onto a pre-combusted 140 mm QMA filter placed on top of the pump filter holder in order to prepare the procedural blank. 2.5 The Salish Sea Box Model The Salish Sea Box Model developed by Wang et al. (2019) provides a useful tool to help interpret the concentrations of PBDEs measured in the water column. The box model divides the Salish Sea into 3 regions: Juan de Fuca Strait, Haro Strait and Strait of Georgia, and each of these regions is further subdivided into 2 boxes representing water above and below 50 m depth (Figure 2.2). The model uses instrumental data and empirical estimates of estuarine circulation to simulate the volume fluxes between boxes. The salinity budget is the primary forcing mechanism of the modelled estuarine circulation, which is driven by freshwater discharge into the SoG and saltwater exchange between the Pacific Ocean and Juan de Fuca strait. Freshwater discharge is based on discharge measurements of the Fraser River at Hope (Station 08MF005) and Englishman River near Parksville (Station 08HB002). The high salinity deep water inflow from 30 the Pacific Ocean into JdFS is defined as a function of coastal wind speed, acquired from La Perouse Bank (Station 46206, National Data Buoy Center), to reflect wind-driven upwelling from late spring to early fall, which brings higher salinity water to the lower JdFS, and wind-driven downwelling from late fall to early spring, which lowers the salinity of the incoming Pacific water. Figure 2.2: Schematic diagram of the box model used to predict PBDE concentrations (Wang et al., 2019). The Salish Sea is divided into 3 basins: SoG, HS, and JdFS, each of which consisting of an upper and a lower box representing water above and below 50m. Volume fluxes between two boxes are represented by thin arrows, and vertical mixing by thick arrows. Time varying water fluxes between boxes are driven by freshwater discharge from the Fraser River into the upper SoG box and upwelling of Pacific water into the lower JdFS (Qh). User-defined contaminants can be incorporated in the model by specifying their constant or time-variable inputs from the Fraser River, the Pacific Ocean, and any other sources such as sewage outfalls (Samuel Stevens; pers. comm.). If the model assumes that the contaminant behaves conservatively, it predicts mean contaminant concentrations expected in the different parts of the Salish Sea represented by each box, in the absence of removal by biological uptake, particle scavenging and sediment burial, or degradation. Comparing modeled and measured PBDE concentrations provides a means of gauging the behavior of the contaminant and assess its sources and sinks. 31 Chapter 3: Source, fractionation and fate of PBDEs in the Strait of Georgia 3.1 Results 3.1.1 Data analysis The data reports provided by AXYS include 40 congeners or co-eluting congeners, many of which are flagged as “<”, for not detected at reporting limit; “K”, for peak detected but did not meet quantification criteria; or “MAX”, for an estimated maximum value (i.e. reported value is an estimated maximum possible concentration). A few congeners are reported as reliable data in all or most of the samples, while many others are found in a few or none of the samples. In order to optimize the use of this complex data set, limits of detection (LoD; pg) and quantification (LoQ; pg) were first established for each PBDE congeners from the variability of their laboratory analysis blanks. LoDs were taken as three standard deviations of the blanks, while LoQs were taken as ten standard deviations (Table 3.1). The amount (pg) of each congener measured in each sample and in the procedural blanks was then removed from the data base if found below detection limits, or was otherwise reported to be above LoD, or above LoQ. Error bars are not reported because determining the precision of PBDE measurements requires replicate analysis which are too onerous. 3.1.2 Laboratory blanks, limits of detection and limits of quantification Laboratory analysis blanks reported with each of the batch of samples sent to AXYS for analysis (9 batches for dissolved PBDEs; 7 batches for particulate PBDEs) were used to estimate limits of detection (LoD) and limits of quantification (LoQ) of the analytical methods. Data points more than 1.5 interquartile range below the first quartile or above the third quartile were considered outliers and removed from the laboratory analysis blank data base (Table 3.1). Limits of quantification vary widely between congeners, from 4 pg for dissolved BDE-126 to 11,509 pg for dissolved BDE-209, and from 6 pg for particulate BDE-126 to 1,539 pg for particulate BDE-209. 3.1.3 Procedural blanks The data from the procedural blanks conducted in the sample processing laboratory or at sea were processed as if they were samples, i.e. the laboratory analysis blank of the 32 corresponding sample batch was subtracted from the procedural blank for each congener, and the resulting value was compared to the LoD and LoQ reported in Table 3.1 to determine which congeners have a detectable or quantifiable procedural blank. For dissolved PBDEs, the procedural blank conducted in the sample processing laboratory in December 2013 (see Chapter 2 for details) did not yield any values above LoD, except for BDE-209, for which the procedural blank (5,580 pg) was above the LoD (3,453 pg) but below the LoQ (11,509 pg) (Table 3.2a). Likewise, the procedural blanks conducted in May 2017 with the CCGS John P. Tully’s Niskin bottles with different closing mechanism (see Chapter 2 for details) yielded values below the LoD, except for BDE-28+33 in the Niskin bottle with silicon tubing (5 pg), which was barely above the LoD (4 pg), and for BDE-183 in the Niskin bottle with metal spring (41 pg), which is also above the LoD for this congener (20 pg) but below the LoQ (67 pg). Note that the Niskin procedural blanks were processed in the same laboratory as the samples, so that the three procedural blanks are quasi replicates. BDE-209 in the latter two procedural blanks were below LoD. These results indicate that the laboratory procedural blank and the blanks associated with the CCGS John P. Tully’s rosette are below LoD for most congeners and none can be estimated quantitatively. The laboratory analysis blanks reported by AXYS have thus been used for blank correction of the samples. An additional procedural blank was conducted at sea in August 2018 onboard the CCGS Vector (Table 3.2b) because samples were processed at sea during a week-long cruise in the Strait of Georgia (see Chapter 2 for details). Values above LoQ were obtained for several congeners suggesting significant procedural blanks when processing samples at sea. However, water column profiles measured in the more pristine northern Strait of Georgia during the same cruise yielded lower values, indicating accidental contamination of the procedural blank. For particulate PBDEs, only one procedural blank was conducted in the sample processing laboratory in December 2013 (see Chapter 2 for details). None of the congeners with less than 9 bromine atoms could be detected, but BDE-209 could be quantified (4,610 pg) (Table 3.2c). 33 3.1.4 Temporal variability of PBDE concentrations in the Strait of Georgia 3.1.4.1 Station S2 Evaluating the temporal variability of dissolved and particulate PBDE was initiated at station S2 in December 2013. The station was sampled at ca. 50 m depth for three consecutive years (Table 3.3). Fifteen dissolved PBDE congeners could be quantified in all three samples, including all the major constituents (>1% w/w) of the “Penta” formulation (BDE-47, -85, -99, -100, -153, -154; Table 1.2), and several of the minor constituents (>0.1% w/w) (BDE-28/33, -49, -66, -155), which were all measured well above their LoQ (Table 3.3a). In contrast, the main congeners of the “Octa” formulation (Table 1.2) were much less prominent, with only BDE-183 and BDE-203 identified in two of the three samples very close to their LoQ. Other congeners, not manufactured in the three main commercial formulations, could also be quantified well above their LoQ (BDE-15, -17/25, -51, -71), suggesting their formation by debromination of manufactured congeners (Salvado et al., 2016). Finally, notwithstanding the relatively large quantity of BDE-209 found in the three samples, this congener could be quantified in only one of them (Table 3.3a). This is because of the large LoQ for BDE-209, resulting from relatively high and variable analytical blanks (Table 3.1a). Indeed, BDE-47 (121 – 189 pg/L), -99 (38 – 91 pg/L), - 100 (11 – 22 pg/L) had the highest dissolved concentrations (Table 3.4a). When quantifiable, the dissolved BDE-209 concentration was also relatively high (106 pg/L). With a LoQ of ca. 11,000 pg and sample size of about 110 L, the minimum quantifiable BDE-209 concentration is about 100 pg/L, which is equivalent to the concentration of the other two main congeners (BDE-47, -99; Table 3.4a). BDE-209 is thus likely to be an important, but difficult to quantify, contributor to the dissolved PBDE load of SoG seawater. Variations in dissolved congener concentrations between the three years of sampling at Station S2 are typically less than a factor of 2 (Figure 3.1). There is a contrasting trend between the less brominated congeners (from BDE-17/25 to BDE-51), which systematically decrease from 2013 to 2015, and the more brominated congeners (BDE-85 to BDE-154), which show the opposite trend (Figure 3.1). 34 Figure 3.1: Dissolved PBDE congeners concentration at Station S2, 50m measured in December 2013 (blue), October 2014 (red), and December 2015 (yellow). Data in Table 3.4a. Fewer congeners could be detected in suspended particles (Table 3.3b). The volume filtered in 2015 (163 L) was too small to quantify any congeners. The much larger volume filtered in 2014 (711 L) resulted in quantifying the main congeners of the “Penta” formulation (BDE-47, -99, -100, -153, and -154) slightly above their LoQ. However, BDE-209 was below the LoD (462 pg). This was in contrast to the sample collected in 2013 (562 L filtered) which had very high BDE-209 (43 ng) and no quantifiable BDE-47, -99, -100, -153, and -154. Relatively high amount of BDE-206, -207, and -208 were also measured in 2013 but these could have been, in part, produced by debromination of BDE-209 during GC-MS analysis (reported by AXYS as “MAX”). While the volume filtered in 2015 was too small to quantify the concentration of any particulate PBDE congeners, low (< 1 pg/L) but quantifiable concentrations of the main 35 congeners from the “Penta” formulation were found in 2014, while BDE-209 was below LoD (0.6 pg/L; Table 3.1b). In 2013, a much higher particulate BDE-209 concentration was found (68.5 pg/L), while the congeners of the “Penta” formulation were below LoD. 3.1.4.2 Station S4-1.5 In 2017, the time-series station was moved to a location farther removed from the Iona outfall and Burrard Inlet, which are the two suspected main entry points of PBDE into the SoG. This move was prompted by the high temporal variability in particulate PBDE concentration observed at Station S2 (Table 3.4b). Station 2 is still located within the dispersion zone of the plume (Hodgins et al., 1999) and higher concentrations could reflect sampling within a filament of the plume that has not yet fully dispersed. Prior to 2017, however, it was logistically difficult to move our time series station further afield because sampling was done from the R/V Strickland. Gaining access to the hovercraft CCGH Siyay greatly reduced transit time, allowing us to sample S4-1.5 within one day. Thus, to document the sub-annual variability of dissolved PBDE concentration over the entire water column, Station S4-1.5 was sampled at several depths six times between February 2017 and August 2018 (Table 3.5a). Particulate PBDE concentrations were measured five times at 25m and 150 m depth (Table 3.5b). The dissolved PBDE congeners that could be quantified at Station S4-1.5 (Table 3.5a) are the same as those quantified at Station S2 (Table 3.3a). They include all the major constituents (>1% w/w) of the “Penta” formulation (BDE-47, -85, -99, -100, -153, -154) and several of the minor constituents (>0.1% w/w) (BDE-28/33, -49, -66, -155), while congeners from the “Octa” formulation (BDE-183, -203) could be quantified in a few samples only. BDE-15, - 17/25, -51, and -71, which have not been manufactured and must have been produced by debromination, were also measurable in all the samples. Because of its large LoQ, dissolved BDE-209 could only be quantified in two of the thirty samples (Table 3.5a). Congener distribution of dissolved PBDE at Station S4-1.5 (Figure 3.2) is very similar to Station S2 (Figure 3.1), but their concentration is much more variable. The dominant congeners are BDE-47, -99, -100, with smaller concentration of BDE-17/25, -28/33, -49, -66, -85, -153, -154. When dissolved BDE-209 concentration is quantifiable, it is lower than dissolved BDE-47 36 concentration but higher BDE-99 concentration, confirming that, although not the dominant congener, it is one of the main congeners contributing to the dissolved PBDE load in the SoG. The depth profiles of dissolved PBDEs concentrations show a large temporal variability, particularly at intermediate depth (Figure 3.3). The profiles of dissolved PBDEs concentrations measured in May 2017 and January 2018 also show a clear mid-depth maximum, which becomes shallower as the degree of bromination of the congener increases (Figure 3.4). In both months, the depth of maximum dissolved concentrations of each congener decreases with the increase of bromination. For instance, BDE-17+25, BDE-47 and 99, and BDE-153 has the highest dissolved concentration at 100-150 m, 75 m and 50 m (Figure 3.4), respectively. In addition, the concentration of these congeners increases from ~ 25 m towards the surface in May 2017. Figure 3.2: Average of dissolved PBDE congeners concentrations measured in the water column at Station S4-1.5. The average concentrations were calculated based on dissolved PBDE concentrations at S4-1.5 in all seasons and depths (Table 3.6a). 37 Figure 3.3: Temporal variation in the dissolved concentration profiles of some of the main congeners measured at Station S4-1.5. Only numbers above LoD are plotted. Data in Table 3.6a. 38 Figure 3.4: Depth profiles of select dissolved PBDE congeners at Stn 4-1.5 in May 2017 (a) and Jan 2018 (b). Stars indicate the LoQ for each measurement. Data in Table 3.6a. The concentration of particulate PBDE at Station S4-1.5 were invariably low and required filtering at least 400 L of seawater. The smaller sample volumes filtered in May 2017 did not allow quantification of particulate PBDE concentrations, while similar volumes provided quantitative measurement of the three main congeners of the “Penta” formulation in September 2017 (Table 3.5b). The larger sample volumes collected in 2018 provided quantitative measurements for BDE-47 in all 2018 samples, while BDE-99, -100, -153, and 154 could be quantified in some of these samples (Table 3.5b). Because of its high LoQ, BDE-209 requires even larger volumes (> 700 L) for quantification. When both BDE-47 and BDE-209 can be quantified in the same samples, the latter is 10 – 20 times larger, suggesting that BDE-209 is the dominant congener associated with suspended particles. However, when correcting for the procedural blank, only one sample could be quantified (yielding a BDE-209/BDE-47 ratio of 4). More filtration procedural blanks are needed to confirm the level of particulate BDE-209 at Station S4-1.5. 39 In contrast to the highly variable particulate PBDE concentrations measured at Station S2 (Table 3.4b), particulate PBDE concentrations at S4-1.5 are invariably low (Table 3.6b). BDE-47 is the only congener that could be quantified in all samples > 400 L. Its average particulate concentration (0.23 pg/L) is 660 times lower than its average dissolved concentration (153 pg/L), indicating that most of the PBDE load in the middle of the SoG is in “dissolved” form (i.e. truly dissolved, colloidal, or associated with particles < 2.2 µm). The other major congeners of the “Penta” formulation are also found in some of the samples at concentration that are more than two orders of magnitude lower than their dissolved concentrations (average particulate concentrations: BDE-99: 0.23 pg/L; BDE-100: 0.05 pg/L; BDE-153: 0.02 pg/L; BDE-154: 0.02 pg/L). Although difficult to quantify, the particulate PBDE concentration appears to be dominated by BDE-209 (Table 3.6b). However, when measurable, particulate BDE-209 is still much lower than “dissolved” BDE-209. Particulate PBDEs were measured five times in a year but no obvious seasonal variability was observed (Figure 3.5). 40 Figure 3.5: Seasonal variability of particulate PBDEs measured at Stn 4-1.5. Since all in-situ large volume pumps were deployed at 25 and 150 m in all cruises, the depths in the figure are shifted by 1-2 meters in order to avoid overlap. Only numbers above LoD are plotted. Stars indicate the LoQ for each measurement. Data in Table 3.6b. 3.1.5 Spatial variability of PBDE concentration in the Salish Sea and the Northeast Pacific Ocean To investigate the spatial variability of PBDE concentration in the Salish Sea, two stations (NG, HS; Figure 2.1a) were sampled in August 2018, and one station in Juan de Fuca Strait (JF2; Figure 2.1a) was sampled twice (June 2017; September 2018; Table 2.1). For dissolved PBDE, a six-depth water column profile was measured at Station NG, while a large composite sample (Table 2.1) was taken from Haro Strait (Station HS) to estimate the average PBDE dissolved concentration of the entire water column (Table 3.7a). At JF2, the ca. 110 L 41 samples collected in June 2017 at two depths were too small to quantify dissolved PBDE concentrations. Larger volumes were collected at the same location in September 2018 (Table 2.1), allowing for the quantification of several congeners (Table 3.7a). In addition, a large volume sample (Table 3.7a) was obtained from the mixed layer at Station P26, in the NE Pacific (Figure 2.1b). Particulate PBDE were also collected at two depths at Station NG (Table 3.7b). Dissolved PBDE concentrations measured at Station NG, HS, and JF2 (Table 3.8a) were much lower than those measured at Station S2 (Table 3.4a) and S4-1.5 (Table 3.6a; Figure 3.6). A six-depth profile was measured at Station NG in August 2018 (Table 3.8a). Only the co-eluting tri-brominated congeners BDE-28+33 were quantifiable at all depths, showing a relatively uniform background concentration of ca. 0.6 pg/L (Figure 3.7). Another co-eluting tri-brominated pair (BDE-17+25) was quantifiable at four of the six depths and the di-brominated congener BDE-15 was quantifiable at five depths. Among the more brominated congeners, only BDE-47 was quantifiable at two depths, but above LoD at the other four depths (Table 3.8a). On the other hand, the larger volume of the composite sample integrating the entire water column in Haro Strait (Station HS; 453.4 L) allowed for the quantification of congeners in the dissolved phase from the “Penta” formulation, dominated by BDE-47 (Table 3.8a; Figure 3.8), confirming the presence at low concentrations of di-brominated BDE-15 (0.06 pg/L), tri-brominated BDE-17+25 (0.26 pg/L) and BDE-28+33 (0.67 pg/L), and tetra-brominated BDE-47 (6.1 pg/L), BDE-49 (0.19 pg/L), BDE-51 (0.04 pg/L), and BDE-66 (0.15 pg/L). The two main penta-brominated congeners (BDE-99 and BDE-100) were identifiable but below LoQ and none of the more brominated congeners were detectable (it should be noted, however, that with a LoD of 3,453 pg for BDE-209, it cannot be ruled out that BDE-209 was present at a concentration as high as 7.6 pg/L, similar to BDE-47). In Juan de Fuca Strait (JF2), where 460 L samples were also collected, the dissolved PBDE concentrations were even lower, so that only BDE-15 and BDE-28+33 could be quantified in the upper water column (20 m; 0.012 pg/L; 0.16 pg/L) and lower water column (160 m; 0.017 pg/L; 0.19 pg/L, respectively), while BDE-47 could only be quantified in deeper sample (2.0 pg/L) but was detectable (ca. 1.7 pg/L) in the shallower sample (Table 3.8a). 42 43 Figure 3.6: Concentrations of dissolved PBDEs measured in all stations in the Salish Sea area. The concentration in May 2017 at S4-1.5 is used as a reference. Only numbers above LoD are plotted. Data in Table 3.4a, Table 3.6a, and Table 3.8a. 44 Figure 3.7: Depth profile of dissolved BDE-28+33 in northern Strait of Georgia (Station NG). Only numbers above LoD are plotted. Data in Table 3.8a. Adding the concentration of quantifiable congeners yield a “total dissolved” PBDE (excluding BDE-206 to 209) concentration of 0.5 – 9 pg/L at NG, 8 pg/L at HS, and 2 pg/L at JF2, compared to 266 – 372 pg/L at S2 and 28 – 898 pg/L at S4-1.5 (Table 3.8a). The total quantifiable dissolved PBDE concentrations measured at NG and HS are similar to those measured by Frouin et al. (2013) at Johnstone Strait (2 – 3 pg/L), Boundary Passage (7 – 14 pg/L), and Rosario Strait (6 – 18 pg/L; Table 1.3), while the concentrations at S2 and S4-1.5 are among the higher levels reported for coastal water, such as Sanggou Bay, Izmir Bay, and San Francisco Bay (Table 1.3). Contamination of the NG and HS samples cannot be ruled out, considering the high procedural blank measured at sea. However, it is clear that the dissolved PBDE concentrations at these two stations are much lower than at Station S2 and S4-1.5. 45 Figure 3.8: Average dissolved congener distribution at Station S4-1.5 (Table 3.6a), as well as HS, NG, and JF2 (Table 3.8a). In comparison to the dissolved congener distribution found at S4-1.5, dissolved congener distribution at HS, NG and JF2 appears skewed toward the less hydrophobic congeners, as all congeners above BDE-100 were below LoD (Figure 3.8). Although BDE-47 was the dominant congener at all stations, this trend suggests that the more brominated and hydrophobic PBDE congeners have been preferentially removed from seawater after discharge. This is confirmed by the higher dissolved concentration ratios of less brominated over more brominated congeners at Station NG, HS and JF2 compared to S4-1.5 (Table 3.9). 46 In contrast to dissolved PBDE concentrations, which decrease sharply between S4-1.5 and NG, particulate PBDE concentrations measured at Station NG (Table 3.8b) were similar to the low concentrations measured at S4-1.5 (Table 3.6b; Figure 3.9). All particulate PBDE congener concentrations were below LoQ at 25m, notwithstanding the large volume of seawater filtered (1,437 L; Table 3.8b). On the other hand, BDE-10, -47, -99, -100, 153, -154, and -209 could be quantified in the sample collected at 150 m depth (Table 3.8b). The particulate PBDE congener distribution of this sample was similar to that of the samples collected at S4-1.5 (Figure 3.10), and dominated by the more hydrophobic congeners, notwithstanding the difficulties in quantifying BDE-209 concentrations. Adding the average of all concentrations above LoD reported in Table 3.6b and Table 3.8b for each congener yields a “total” particulate PBDE concentration of 4.2 pg/L at S4-1.5 and 3.6 pg/L at NG. These values are also similar to the total particulate PBDE concentrations reported by Frouin et al. (2013) at Johnstone Strait (3 – 8 pg/L; Table 1.3). 47 Figure 3.9: Concentrations of particulate PBDEs measured in all stations in the Salish Sea area. Only numbers above LoDs are plotted. Data for S4-1.5 in Table 3.6b, and for NG in Table 3.8b. 48 Figure 3.10: Average particulate PBDE congener concentrations at Station NG (Table 3.8b) vs average particulate PBDE congener concentrations at Station S4-1.5 (Table 3.6b). 3.1.6 Sources of PBDE to the SoG The distribution of PBDE concentration in SoG sediment points to the Iona outfall and Burrard Inlet as the two main points of PBDE discharge (Johannessen et al., 2008a). Since several wastewater treatment plants from the Greater Vancouver area also discharge effluent in the Fraser River, the latter could also be an important contributor to PBDE input in the SoG. 3.1.6.1 Iona effluent plume Dissolved and particulate PBDEs were sampled in Iona plume in December and October 2013, respectively. The dissolved PBDE congeners that could be quantified within the Iona 49 effluent plume (Table 3.10a) were the same as those found at Station S2 (Table 3.3a) and S4-1.5 (Table 3.5a). They included all the major constituents (>1% w/w) of the “Penta” formulation (BDE-47, -85, -99, -100, -153, -154), and several of the more minor constituents (>0.1% w/w) (BDE-28/33, -49, -66), which were all measured well above their LoQ. In contrast, the main congeners of the “Octa” formulation were not measurable. The same congeners, not directly manufactured, found at S2 and S4-1.5 (BDE-15, - 17/25, -51, -71) could also be quantified in the plume, suggesting their formation by debromination is happening prior to discharge in coastal waters. Finally, dissolved BDE-209 was detectable but not quantifiable but was much lower than the dominant BDE-47 congener (Table 3.10a). Surprisingly, the dissolved PBDE concentrations measured in the effluent plume (Table 3.11a) are similar to the dissolved PBDE concentrations measured at Station S2 (Table 3.4a; Figure 3.11). In addition, the concentrations of less brominated congeners (BDE-47 and lower) are higher in the effluent plume, while the concentrations of the more brominated congeners (BDE-85 and higher) are higher at Station S2 (Figure 3.11). Figure 3.11: Dissolved PBDE congener concentrations in the effluent plume (Station S1, Table 3.11a) and average concentrations measured at Station S2 (Table 3.4a). 50 The same congeners found in the dissolved PBDEs were also found in the particles suspended in the plume (Table 3.10b). However, while congener distribution of dissolved PBDE is skewed towards the less hydrophobic and less brominated congeners, the opposite is observed in the particles, where BDE-209 is above LoQ and the dominant congener (Figure 3.12). Figure 3.12: Dissolved (Table 3.11a) and particulate PBDE congener concentrations (Table 3.11b) measured in the effluent plume (Station S1). Although the particulate PBDE congener distribution within the Iona plume and Station S4-1.5 are similar and dominated by BDE-209 (Figure 3.13), their concentrations are much higher in the Iona plume (Table 3.11b) than measured at Station S4-1.5 (Table 3.6b), pointing to the Iona outfall as a direct point source of particulate PBDEs. 51 Figure 3.13: Particulate PBDE concentrations at Station S1 (Iona outfall, Table 3.11b) and average concentration at Station S4-1.5 (Table 3.6b). 3.1.6.2 Burrard Inlet The Port of Vancouver and several industrial areas are located on the shores of Burrard Inlet. Sediment analysis has identified this area as a point source for PBDEs and PCBs (Grant et al., 2011). Dissolved (Table 3.10a) and particulate (Table 3.10b) PBDEs were sampled in the Inner Harbor (Station S3; Fig. 2.1a) near the port, in December 2014, and twice (December 2015 and August 2016; Table 2.3) in the Central Harbor (Station 3b), in the vicinity of industrialized zones. The dissolved PBDE congener concentrations measured at Station S3 were similar to those measured in the Iona effluent plume, but the distribution pattern was more skewed towards the more hydrophobic congeners (Figure 3.14a; Table 3.11a). At Station S3b, dissolved PBDE concentrations were similar at both sampling time and about half that of Station S3, except for BDE-209, which was not detectable. 52 Particulate PBDE concentrations were about 5 times lower at Station S3 than at Station S1 (Figure 3.14b), although BDE-209 was the dominant congener at both stations (Table 3.11b). The dominance of BDE-209 is also recognized at Station S3b, but particulate concentrations measured in December 2015 were one order of magnitude higher than measured in August 2016 (Figure 3.14b). Figure 3.14: Dissolved and particulate PBDE concentrations at Station S1 (Iona effluent plume) vs Station S3 (Inner Harbor; Burrard Inlet) and S3b (Central Harbor; Burrard Inlet). Data in Table 3.11a and Table 3.11b. 53 3.1.6.3 Fraser River To investigate whether the Fraser River could be a source of dissolved and particulate PBDEs, the river was sampled twice (Table 2.3), during the freshet in spring and during the time of lowest river discharge in winter. All samples were collected downstream of Metro Vancouver’s wastewater treatment plant on Annacis Island, the largest source of effluent discharged into the Fraser River, located on the southern branch of the Fraser River. Two different sampling methods were used. In summer, the dissolved PBDE sample was collected close to the center of the river using Go-Flo bottles following the method in Section 2.2.1. The large volume in-situ pumps were not required to measure particulate PBDE in the Fraser River, because of its much larger particle load compared to seawater. Instead, particulate and dissolved PBDEs could be obtained from the same sample by on-line filtration and XAD adsorption. In winter, we collected three samples across the river and mixed them into one composite sample. The sample’s salinity was zero. Because of the high concentration of particles in the Fraser River, the sampling method in the winter was modified to avoid using our Go-Flo bottles. Instead, seawater was pumped into 20 L acetone-washed glass carboys using 4 m of copper tubing attached to a vacuum pump. The water was then transferred into our aluminum kegs for processing. The particulate PBDE sample was collected on pre-combusted QMA filters. Dissolved PBDE concentrations are similarly low at both times of sampling (Table 3.11a). They are dominated by congeners from the “penta” formulation, which are found at concentration much lower than in the surface water of S4-1.5 at the same time of the year (Figure 3.15). BDE-209 concentrations are below LoD. On the other hand, particulate PBDE concentrations are much higher during the freshet compared to the concentrations measured in winter (Figure 3.16). Even in winter, however, particulate PBDE concentrations in the Fraser River are higher than the average concentrations measured at S4-1.5 (Figure 3.16). While particulate PBDE appear dominated by BDE-209 in the SoG and in the FR at low flow, during the freshet, the congeners from the Penta formulation become more prominent (Figure 3.16). 54 Figure 3.15: Dissolved PBDE concentrations in the Fraser River (FR) during high (June 2017) and low (February 2018) water discharge compared to concentrations at S4-1.5 in May 2017 and February 2017. 55 Figure 3.16: Particulate PBDE concentrations in the Fraser River, during high (June 2017) and low (February 2018) water discharge, compared to the average particulate PBDE concentrations at Station S4-1.5 in all seasons and from all depths. 3.1.7 Dissolved PBDE concentrations in the mixed layer of the Alaskan Gyre in the NE Pacific (Station P26) A large volume sample was collected to measure dissolved PBDE concentration in the open NE Pacific. This is the only sample whose dissolved PBDE load was dominated by BDE-209 (Table 3.8a). BDE-15, -28+33, -47, and -203 could also be quantified but at much lower level. 3.2 Discussion 3.2.1 Working hypotheses PBDE congeners are hydrophobic and lipophilic, and these properties increase with the degree of bromination of the congeners. Therefore, in the Iona effluent, which has a relatively high particle load and organic content, PBDEs are expected to be mostly associated with particles, and more so for the more brominated congeners, although the high concentration of dissolved organic matter in effluents could keep a higher proportion of PBDE in solution than expected otherwise (Kim et al., 2013; Song et al., 2006). Upon discharge and mixing with coastal 56 waters, with much lower particle concentrations than in the effluent, particulate PBDE concentrations are expected to decrease, and the evolution of the partitioning between the dissolved and particulate phase for each congener is expected to depend on the partition coefficients between particles and seawater (i.e. the ratio at equilibrium of PBDE congener concentrations in particles over their concentration in seawater), on the congeners’ kinetics of desorption from sewage particles, and on their adsorption kinetics on marine particles. Assuming that dissolved and particulate PBDEs concentrations in the Iona effluent are near equilibrium, upon mixing in coastal water with much lower dissolved PBDE concentrations, desorption of PBDEs from effluent particles into seawater is expected, with each congener desorbing from sewage particles at a rate dictated by its desorption rate constant. Since a fraction of the particles discharged from the outfalls rapidly settles on the seafloor, the ultimate fate of the PBDE congeners discharged with sewage particles will depend on their rates of desorption from, and the settling rates of, sewage particles; congeners desorbing faster will preferentially contribute to the dissolved load of seawater, while congeners desorbing at slower rates will preferentially be removed in the sediment near the point of discharge if associated with fast-sinking sewage particles, or further afield if associated with smaller sewage particles discharged directly or produced by fragmentation of the larger sewage particles during mixing. If the rates of desorption are very slow, as could be expected from hydrophobic compounds such as PBDEs, dissolved PBDE concentration should remain low. If significant fractions of PBDE congeners associated with Iona sewage particles are released to seawater before burial in sediments, they can then (1) be transported with currents and potentially exported to the Pacific Ocean, or (2) be re-adsorbed on the surface of uncontaminated marine particles (plankton, lithogenic particles, marine snow, fecal pellets, etc.), which can, in turn, settle, thereby removing the discharge PBDEs in sediments farther removed from the point of discharge, or (3) be taken up by marine organisms and enter the food chain. In the following, the extent to which these scenarios are supported by the data is discussed. 57 3.2.2 PBDEs in the effluent of the Iona Island WWTP and their accumulation in SoG sediments PBDE concentrations in the Iona effluent have not be measured as part of this project, but the 2004-2005 average total (dissolved + particulate) concentration and discharge rate of measurable congeners and their sums have been reported (∑[PBDEs] (dissolved + particulate): 130 ng/L; total PBDE flux ∑FPBDEs: 24 kg/y; (Dinn et al., 2012a). The partitioning of PBDEs between the dissolved and particulate phase of the Iona effluent is not known. However, since a large fraction of PBDE entering WWTPs is removed during primary treatment with the settling sludge (Clarke et al., 2010; Kim et al., 2013; Rayne et al., 2005; Song et al., 2006), a large fraction of the total PBDE measured in effluents must be associated with particles. This is confirmed by Song et al. (2006), who found that ca. 90% of the BDE-47, -99, -100 load in the effluent from a primary settling tank was associated with particles. Dinn et al. (2012a) reported that only ca. 10% of the PBDE discharged by the Iona outfall accumulates in sediments within the near-field region of the outfall. They attributed the dispersal of most of the discharge PBDEs beyond the near-field of the discharge point to their association with fine particles that sink slowly, in which case most of the PBDE measured in the water column of the SoG would be associated with fine particles. An alternative explanation, however, would be the relatively rapid desorption of PBDE from sewage particles, in which case, most of the PBDE in the water column would be in dissolved form. The lower BDE-47/BDE-209 and BDE-99/BDE-209 ratios found in proximal sediments compared to the same ratios in the Iona effluent (Dinn et al., 2012a) indicate fractionation of PBDEs between congeners of different particle-reactivity during the initial dilution and dispersion of the effluent, which supports the desorption hypothesis since fragmentation to fine particles is not expected to fractionate PBDE congeners. Once released to seawater in dissolved forms, PBDE can be either exported to the Pacific or removed into more distal SoG sediments. Kow, defined as the ratio of the concentration of a specific compound in octanol versus in water when equilibrium is reached at a specific temperature, is the key parameter to represent a compound’s affinity to organic matters. The higher Kow is, the stronger affinity to organic matters the compound has. For PBDEs, congener’s affinity for particles increases with the increase of the level of bromination, as well as the increase of Kow values, leading the slower desorption from particles. Grant et al. (2011) have 58 shown that the concentration-weighted average log Kow of sediments accumulating in the deep basins of the SoG tends to be higher than in sediments deposited at shallower depths and presumably closer to their sources. If confirmed, that trend would indicate that a significant fraction of the less brominated congeners discharged in the SoG is exported to the Pacific Ocean by the SoG’s estuarine circulation. If instead the less brominated congeners were scavenged into distal SoG sediments, then, based on a simple mass balance argument, distal SoG sediments would have a lower average log Kow. 3.2.3 Partitioning of PBDE between dissolved and particulate phases in the water column of the SoG If the desorption hypothesis is correct, we should find a smaller particulate contribution to the PBDE load in the water column of the SoG than found in the effluent. If far-field transport is due to the dispersion of fine particles (here define as > 2.2 μm), the % particulate, defined as particulate/(dissolved + particulate) of each congener, should remain the same as in the effluent (ca. 90%). The particulate PBDE concentrations in the southern SoG water column (Station S4-1.5) are very low and often difficult to quantify (Table 3.6b). The particulate fraction can be calculated when both dissolved and particulate concentrations for the same sample are above LoQ (Table 3.12). If we assume that the particulate PBDE contribution in the Iona effluent is similar to the 90% reported by Song et al. (2006) for BDE-47, -99, and -100, the particulate PBDE contribution in the water column of the SoG for the same congeners is much lower (< 1%; for BDE-47 and -99; < 2% for BDE-100; Figure 3.17a), and points to the desorption of a substantial fraction of PBDEs from sewage particles into seawater during their dispersion in the water column of the SoG. However, the operationally defined “dissolved” fraction includes small particles (< 2.2 μm) and colloids, which could potentially form from the fragmentation of the sewage particles, instead of desorption. If such were the case, since the fragmentation of particles is not expected to fractionate the different PBDE congeners, we would expect that the change in % particulate between the effluent and SoG water would be the same for all congeners. Unfortunately, Song et al. (2006) could only quantify % particulate in primary treatment effluent for BDE-47, -99, and -100, because of the difficulty in quantifying the dissolved fraction for the more brominated 59 congeners. Nonetheless, considering that 90% of BDE-47, -99, -100 congeners were found in particles, the particulate fraction for the more brominated congeners could only be slightly higher. Although not collected on the same day, the dissolved and particulate PBDE concentrations measured at Station S1 shows a striking contrast in % particulate for congeners with different level of bromination (Figure 3.17b). Considering that all congeners from BDE-47 to BDE-209 must have had a fraction of particulate of at least 90% in the effluent (Song et al., 2006), the results from Station S1 suggest very extensive desorption of the less brominated congeners in the initial dilution zone (IDZ) (e.g. % particulate BDE-47 dropped from ca. 90% to 4%), and a sharp fractionation between congeners with different degree of bromination (e.g. % particulate BDE-99 and -100 dropped from ca. 90% to ca. 20%; BDE-153 and -154 from > 90% to ca. 55%; BDE-209 from >90% to ca. 70%). The data from Station S4-1.5 also show a general increase in % particulate with the degree of congener bromination (Figure 3.17a), but the increase in % particulate vs bromination is not as pronounced. This observation could be explained by lower rates of desorption of the more brominated congeners. Fractionation between congeners is a clear indication that the decrease in % part in seawater is due to desorption from sewage particles rather than the fragmentation of these particles. Figure 3.17: % fraction of particulate PBDE congeners (a) at Station S4-1.5 in the southern SoG (S4-1.5) , and (b) at Station S1 in the Iona effluent plume close to the diffusers. 60 However, deployments of passive samplers, which only measure the truly dissolved fraction of PBDEs (e.g. Sacks and Lohmann, 2012), have shown that most of the operationally defined “dissolved” fraction (< 2.2 μm) is associated either with dissolved organic matter or colloids. The fractionation observed in Figure 3.17 thus implies that congeners must first desorb from the particle before associating with dissolved organic matter or colloids (with less hydrophobic desorbing faster and preferentially), to account for their higher content in less brominated congeners in the dissolved form. It should be noted that % particulate for BDE-209 could not be measured on any of the samples. Dissolved BDE-209 concentration could only be quantified in two of the 30 samples (February 2017 @ 55m; May 2017 @ 150m; Table 3.6a) for which particulate BDE-209 could not be quantified, while particulate BDE-209 could be quantified in four samples (January 2018 @ 25 m & 150 m; April 2018 @ 25 m and 150 m; Table 3.6a) for which dissolved BDE-209 could not be quantified. Nonetheless, when measurable, particulate BDE-209 concentration ranged between 1.4 – 6.2 pg/L vs 377 pg/L and 130 pg/L for dissolved BDE-209, indicating that even the most hydrophobic congener is still primarily found in the “dissolved” fraction of the SoG seawater. 3.2.4 Spatial variation of dissolved and particulate PBDE concentrations in the Salish Sea The spatial distribution of PBDE concentrations in seawater can provide insight into the location of point sources, similarly to the spatial distribution of PBDE concentrations in sediments (Grant et al., 2011; Johannessen et al., 2008b). In order to facilitate comparison, the average total quantifiable (i.e. sum of all quantifiable) and total detectable (i.e. sum of all quantifiable and detectable) congener concentrations were compared between Stations S1, S2, S4-1.5, S3, S3b, NG, and HS (Table 3.13). Summing up all the concentrations of quantifiable congener concentrations provides a more robust number, which could, however, underestimate total concentrations if many congeners were at concentrations just below their LoQ and well above their LoD. Adding up all concentrations above LoD takes into account these congeners, but if they weigh significantly, the calculated total concentrations are less reliable. Combining both provide a means of assessing the validity of the calculated total concentrations (Table 3.13). Ideally, the two sums should be similar, indicating that missing the congeners below LoQ is not significant. 61 The total particulate PBDE concentration measured in the effluent plume near the Iona Island diffusers (Station S1) is about two orders of magnitude higher than those measured in the seawater of the southern SoG at Station S4-1.5 and the northern SoG at Station NG (Table 3.13). This confirms that the Iona effluent is an important point source of particulate PBDE in the SoG (Grant et al., 2011; Johannessen et al., 2008a). At Station S2, where PBDE concentration was measured once in three consecutive years, the total particulate PBDE concentration is highly variable and can be as low as in Station S4-1.5 or as high as half of the concentration measured at S1. This variability has been attributed to the S2 location being within the dispersion zone of the Iona Island plume (Hodgins et al., 1999), which is dispersed predominantly northward, following the intermediate water inflow which enters the southern SoG as an eastern boundary current (Pawlowicz et al., 2007). It could also reflect proximity to the entrance of Burrard Inlet, which has also been identified as a potential source of particulate PBDE (Johannessen et al., 2008a). Total particulate PBDE concentrations were also measured once in the Inner Harbor of Burrard Inlet (Station S3), where the Port of Vancouver is located, and twice in the Central Harbor of Burrard Inlet (Station S3b) at a location farther removed from the SoG but close to heavily industrialized shorelines. These stations are relatively shallow and potentially subject to sediment resuspension. The total particulate PBDE concentration measured at S3 was relatively high (ca. 30 pg/L) but not as high as measured within the effluent plume at S1 (ca. 190 pg/L), while at Station S3b, the particulate PBDE concentration was as low as measured in the SoG (< 10 pg/L) or nearly as high as measured in the Iona effluent plume at S1 (Table 3.13). The variability of particulate PBDE concentration at S3b is related to the tidal cycle. In-situ filtration to collect suspended particles on December 16, 2015 was conducted between 1 and 2 pm, mid-way between high (9:30 am) and low slack water (5:30 pm) when tidal currents were high, accounting for the high particulate PBDE concentration from resuspension of contaminated sediments present at this location (Grant et al., 2011). In contrast, sampling on August 31, 2016 was conducted between 11 am and noon, which was just after low slack water (10:30 am), when tidal currents were weak, accounting for the very low particulate PBDE concentration measured at that time. Whether sediment resuspension by tidal currents can export a significant amount of particulate PBDE from Burrard Inlet into the SoG is still an open question. 62 The average total dissolved concentration is clearly very high (ca. 300 pg/L) at the stations in the southern SoG (S1, S2, S4-1.5) and in the Inner Harbor of Burrard Inlet (S3), which is in direct tidal exchange with southern SoG (Table 3.13). In comparison, the Central Harbor of Burrard Inlet (S3b), which is farther removed from the southern SoG has a significantly lower total dissolved PBDE concentration (ca. 60 pg/L). Much lower concentrations of dissolved PBDEs are found in the northern SoG (NG) and Haro Strait (HS; < 10 pg/L), while the lowest concentrations are found in Juan de Fuca Strait (JF2). The sharp drop in dissolved PBDE concentration from Stations S1, S2, and S4-1.5 to the other stations indicates that the main source of dissolved PBDE in the SoG is in the southern region of the SoG off Vancouver, and it most likely reflects input from the Iona Island diffusers, which discharge wastewater at 70 – 105 m below the surface near Station S1. Additional contributors could include the Lion’s Gate primary wastewater treatment plant, which discharges effluent at 20 m depth near the entrance of Burrard Inlet, and the Fraser River, which receives effluent from the secondary wastewater treatment plants serving the Greater Vancouver area (Northwest Langley, Annacis Island, Lulu Island). The much lower concentrations measured at Station NG and in the water of Haro Strait must be a result of dilution of the discharged effluent by Pacific water, which contains low PBDE concentrations, entering the SoG through Juan de Fuca and Haro Strait, and/or removal by adsorption on the surface of settling particles (a process called “scavenging”). However, the similar concentrations found in the Iona effluent plume close to the point of discharge (Station S1) and southern SoG stations farther afield (S2, S4-1.5) indicate that the Iona diffusers cannot be a direct point source for dissolved PBDEs. If such were the case, we would expect to find much higher dissolved PBDE concentrations at S1 compared to the other stations in the southern SoG. This observation is consistent with the evolution of % particulate, from which it was deduced that dissolved PBDEs, which comes to dominate the PBDE load in the water of the southern SoG, are produced by desorption from sewage particles, as they disperse from their point source at the Iona outfall. Therefore, although not a direct point source, the Iona outfall may still be one of the main ultimate sources of the dissolved PBDEs found in the water column of the southern SoG. Particulate PBDEs added to the water column by resuspension of sediment, as observed in the Central Harbor of Burrard Inlet, behave very differently from sewage particles. While 63 particulate PBDEs in sewage particles approach equilibrium with the high dissolved PBDE concentrations found in the effluent (ca. 130 ng/L, Dinn et al., 2012b), sediments are in equilibrium with the much lower dissolved PBDEs found in bottom water. Therefore, while sewage particles could be expected to release a large fraction of their PBDE load as dissolved PBDEs when dispersing in seawater, particles produced by resuspension of bottom sediments could not. Such resuspension at Station 3b increased total particulate PBDE concentration from < 10 pg/L to 130 pg/L, particularly for the more hydrophobic congeners (Figure 3.18) that are found at higher concentration in contaminated sediments (Grant et al., 2011), but without significantly changing the total dissolved PBDE concentrations (from 55 pg/L to 74 pg/L). The congener distribution of suspended particles at Station S3 and S3b are very similar to the congener distribution in sediments from the same area (Figure 3.19), consistent with suspended particles at these stations being primarily resuspended local sediment. However, suspended particles seem lower in BDE-17+25, suggesting desorption of the less hydrophobic congeners during resuspension, which could contribute to the ultimate export of these congeners to the Pacific Ocean by water circulation. Figure 3.18: % fraction of particulate PBDE congeners concentrations over the total at the Inner Harbor (Station S3) and the Central Harbor (Station S3b) in Burrard Inlet. Station 3b was sampled during high tidal current while other samples were not. Data in Table 3.11a and Table 3.11b. 64 Figure 3.19: Relative congener proportion in suspended particles collected at S3 and sediments from Burrard Inlet (Grant et al., 2011). For suspended particles at S3, the ratio is the particulate congener over total particulate concentrations. For sediment at S3 and S3b, the ratio is the congener concentration at the surficial sediment divided by the total surficial sediment concentrations. 3.2.5 Depth profiles of dissolved PBDE concentration at the time-series Station S4-1.5 While the spatial distribution of dissolved PBDE concentration in the Salish Sea indicate that the main point of entry of PBDE into the SoG is located in the southern region of the Strait, the depth profiles of dissolved PBDE concentration at S4-1.5 can further pinpoint the sources within this region. While the five dissolved concentration profiles of the sum of quantifiable congeners measured between May 2017 and August 2018 at Station S4-1.5 are different, they all show a subsurface maximum in the intermediate water between ca. 50 m and ca. 150m (Figure 3.20). Although determining the exact depth of maximum concentrations is limited by low 65 sampling resolution, concentration maxima occurred at different depths. In May 2017, there was a well-defined maximum approaching 500 pg/L at 65 m. A less prominent maximum (ca. 300 pg/L) was also observed at this depth in April 2018. In January 2018, total PBDE concentration was much lower (ca. 100 pg/L), and the subsurface maximum was broader and deeper (75 – 100 m). At the end of summer (September 2017 and August 2018), the maximum concentration was observed at shallower depths, with a sharp maximum of ca. 300 pg/L at 30 m in September 2017 and a broader maximum at 30 – 60 m in August 2018. 3.2.5.1 PBDEs input from Metro Vancouver’s primary wastewater treatment plants These subsurface concentration maxima likely reflect input from the Iona diffusers that are discharging effluent between ca. 70 and 105 m depth. Since the effluent has a lower density than ambient seawater, the effluent plume rises during mixing within the initial dilution zone (IDZ, i.e. the zone extending up to 100 m horizontally in all direction of the discharge point), until it reaches its buoyancy or “trapping” depth. The depth to which the plume rises depends on the turbulence of the receiving environment, which is controlled in large part by the current velocity at the point of discharge, and to a lesser extent by the discharge rate of the effluent and water column stratification (Li Gu; pers. comm.). Current velocities at the Iona diffusers have a tidal (±40 cm/s) and smaller subtidal (±20 cm/s) component (R. Pawlowicz; Metro report 2017). Therefore, when both components are equal in intensity but opposite in direction, the net current velocity at the outfall is zero. This happens mostly when approaching maximum ebbing tide since subtidal currents at this location are mostly northward, but sometimes when approaching maximum flood tide when subtidal currents flow south. When currents are near zero, mixing of the effluent occurs mostly as the plume rises vertically, thereby reaching its shallowest depth. When tidal currents are strong, however, most of the mixing occurs as the plume moves in a more horizontal direction, and the plume reaches its buoyancy level at greater depth. Effluent discharge rates, which are mostly controlled by meteorological conditions, can also have an influence on the trapping depth of the plume. The discharge at Iona during the dry summer months (June to October) is at its lowest and more constant flow (ca. 100 million litre per day (MLD), but increases sharply and intermittently to > 400 MLD during the rainy season (November to May). Lower discharge rates result in more rapid dilution and greater trapping 66 depth in summer (Li Gu, pers. comm.). Likewise, stronger water column stratification in summer also keeps the plume trapping depth below 25 m above the point of discharge, i.e. 45 to 80 m depth for the shallowest to deepest Iona diffusers, respectively. Preliminary findings by Seaconsult Trapping modelling studies suggest that the trapping depths during winter, when the water column is less stratified, could be as shallow as 25 m, although the median modelled trapping depth is 50 – 65 m (Li Gu; pers. comm.). The buoyancy depth of the Iona plume at the IDZ boundary is thus expected to vary daily and seasonally between 25 and 80 m depth, but mostly between 40 and 60 m, and to reach shallower depths in winter when effluent flow rates are higher, and water column stratification is weaker. Beyond the IDZ, the plume is advected into the southern SoG by the prevailing eastern boundary current and mixes further both isopycnally and diapycnally. While both types of mixing contribute to lowering the concentration of discharged contaminants, the latter also increases the depth range of the diluted plume. (a) 67 Figure 3.20: (a) Dissolved concentration profiles of the sum of quantifiable congeners (excluding deca- and nona-congeners) at Station S4-1.5 (Table 3.6a). BDE-209 is excluded from the sum because its LoQ is high (Table 3.1) and it is found at the concentration above LoQ only in a few samples, while the nona-brominated congeners are co-varying with BDE-209 and are in part produced by debromination of BDE-209 during analysis (flagged as MAX by AXYS). (b) The dark blue line is the temperature measured at the ONC node located at 170m just south of the outfall (49.0423°N; 123.3171°W); the light blue line is the seasonal temperature variation in the intermediate water entering the SoG at 170m depth; the red line is the seasonal temperature variation in the intermediate water exiting the SoG. Blue circles are the temperature measured during sampling at S4-1.5 at 170m depth. The high concentrations measured at ca. 60 m depth in May 2017, April 2018 and August 2018, can thus be explained by the Iona outfall, but the origin of the shallower peaks (~ 25m) measured at the end of summer in 2017 and 2018 is less evident since the trapping depth of the Iona plume in the IDZ is deeper at this time of the year. Increased estuarine circulation as a result of the freshet could possibly bring the Iona plume to shallower depths, or there is another source of PBDE to the shallower part of the SoG water column. The latter could be the Lion’s Gate WWTP, which discharge primary effluent at a depth of 20 m at the mouth of Burrard Inlet, with a trapping depth of 15 m (Li Gu; pers. comm). Although its discharge rate is about seven times lower than Iona (83 MLD vs 562 MLD in 2017; The 2017 Greater Vancouver Sewerage and (b) 68 Drainage District Environmental Management and Quality Control Annual Report), the mixing of contaminants discharged by this plant is restricted to the upper few tens of meters of the water column, which could limit its dilution. 3.2.5.2 PBDEs input from the Fraser River and Metro Vancouver’s secondary treatment plants Four of the water column profiles include a surface sample (Figure 3.20). In two instances, there was either a surface maximum (May 2017, April 2018) or a surface minimum (September 2017, August 2018). The dissolved PBDE concentration could be influenced by input from the Fraser River, which receives effluent from the secondary wastewater treatment plants serving the greater Vancouver area (Northwest Langley, Annacis Island, Lulu Island). Measurements in the Fraser River were done during the freshet in June 2017 and during low water flow in February 2018. Dissolved PBDE concentrations were similarly low at both times of sampling and much lower than the dissolved PBDE concentrations measured at any time in surface water at Station S4-1.5 (Table 3.14; Figure 3.15). These low concentrations clearly indicate that the Fraser River cannot be the source of PBDEs accounting for the surface concentration measured in the SoG. Instead, the Fraser River would tend to lower the surface dissolved PBDE concentration by dilution. The similar concentration of dissolved PBDEs measured during the freshet when the Fraser River flow rate was 6,508 m3/s and in winter when the river flow was only 798 m3/s suggests that effluent discharge from the Annacis Island treatment plant does not control the dissolved PBDE concentration of the Fraser River, which would otherwise be higher in winter when the flow of the Fraser River is lower. Although PBDE effluent concentrations are typically higher in summer than in winter (Kim et al., 2013), that could not account for the near constancy of the dissolved PBDE concentration in the Fraser River, since the changes in effluent concentration are ~3-fold, while the change in the Fraser discharge in 8-fold. Moreover, the higher PBDE effluent concentrations measured in summer also coincide with lower effluent discharge rates, so that the PBDE discharge rate is nearly constant. The near constancy of dissolved PBDE concentration in the Fraser River thus indicates that the PBDE discharged by the river to the SoG originates from the drainage basin. 69 In contrast, particulate PBDE concentrations in the Fraser River are much higher during the freshet (total concentration: 99 pg/L [quantifiable]; 114 pg/L [detectable]) compared to the concentrations measured in winter (total concentration: 3 pg/L [quantifiable]; 14 pg/L [detectable]; Figure 3.16), indicating that particulate PBDEs discharged to the SoG by the Fraser River originate from the drainage basin, as for the Fraser dissolved load. 3.2.5.3 PBDEs input from the atmosphere Maximum concentration at the surface could also indicate atmospheric input. Quantifying this input, however, requires measurement of PBDE concentration in the vapour phase and in aerosols, and estimates of dry and wet deposition, none of which are available at present. Organic contaminants can be added to surface water from the atmosphere in three ways; through gas exchange, wet deposition (rain) or dry deposition (aerosols). Less brominated congeners are more volatile and are expected to be found in the atmosphere in relatively higher concentrations than the more brominated congeners. On the other hand, the more brominated congeners are expected to have a stronger affinity for particles, and to be added to surface water by dry deposition. Interestingly, congener ratios show a systematic trend in the upper water column (Figure 3.21). Lighter congeners have a decreasing ratio to BDE-47 towards the surface, while heavier congeners have an increasing ratio, suggesting preferential addition of heavier congeners to the surface, suggesting addition by dry deposition (Li et al., 2015). Similarly, the high concentration of dissolved BDE-209 quantified at Station P26 in the Pacific Ocean could also have been transported through aerosol, which suggests that aerosol transport may affect the PBDE concentrations in the SoG and contribute heavy congeners into the water. 70 Figure 3.21: Depth profiles of dissolved PBDEs congener to BDE-47 ratio in May 2017 at S4-1.5. Data in Table 3.6a. 3.2.5.4 Reverse scavenging of dissolved PBDEs in the water column of the SoG Surprisingly, PBDE concentrations are relatively high over the entire water column even at the depth well below where the Iona diffusers are located (75-105 m depth). In September 2017, April 2018, and August 2018, dissolved PBDE concentrations increase in deeper water (Figure 3.20a), reaching levels similar to the intermediate water subsurface maxima. Such increases in concentration at greater depth cannot be explained by vertical mixing. Instead, they suggest adsorption on the surface of sinking particle at shallower depths and release from particles in deeper water, as organic matter in settling particles decomposes during settling or at the sediment-water interface. Further studies are required to confirm and quantify this potentially important process bringing high PBDE concentration in deep waters of the SoG. 71 3.2.6 Temporal variations in dissolved PBDE concentration at Station S4-1.5 in relation to the water circulation in the SoG The water column of the SoG is subdivided into three layers: the surface water, down to about 50 m depth, the intermediate water between 50 m and 200m, and the deep water below 200 m (Pawlowicz et al., 2007). The surface layer is formed by mixing fresh water, added from the rivers around the Strait, and saline water upwelling from below. Surface water leaves the Strait by flowing through Haro and Juan de Fuca Strait to the NE Pacific (Figure 1.2). Circulation below the surface to 50 m appears complex and is poorly understood. The water in the intermediate layer originates from Haro Strait, where outflowing SoG surface/intermediate water and inflowing Pacific Ocean water are tidally mixed, thereby partially homogenizing the water column. Intermediate water enters the SoG as a boundary current along the eastern slopes of the Strait, passing by the Iona outfall before mixing into the interior, where it remains for 160 days on average (Pawlowicz et al., 2007). The water eventually leaves this depth range by gradually upwelling into the surface layer, reflecting the prevailing estuarine circulation of the Strait, or flowing back into Haro Strait at intermediate depths. Deep water that fills up the deeper parts of the SoG is renewed annually in summer. Deep water renewal is triggered by stronger wind-driven upwelling off the west coast of Vancouver Island, which brings denser water from the Pacific into Haro Strait (Figure 1.2). At neap tides, when tidal mixing in Haro Strait is minimum, this denser water overflows and cascades down to the deep basin of the SoG. At the end of summer, when coastal upwelling ceases, deep water renewal stops. The salinity of deep water then gradually decreases through winter and spring, as a result of diapycnal mixing, which reduces the density of deep water, allowing for its replacement on the following summer. Significant changes in PBDE concentrations were observed in each of the three layers during the time series measurements at Station S4-1.5. In the following sections, these changes are discussed in relation to circulation. 72 3.2.6.1 Intermediate water (50 – 200 m) The temperature and oxygen concentration of Haro Strait water vary sinusoidally in response to seasonal changes in air temperature. As intermediate water enters the SoG from Haro Strait as an eastern boundary current passing by the Iona outfall, the sinusoidal temperature and oxygen concentration variation imparted to Haro Strait water (higher temperature and lower oxygen in summer) propagates into the SoG with a delay reflecting transit time, which produces continuous spatial-temporal variations in the temperature and oxygen level of SoG intermediate water (The 2018 Greater Vancouver Sewerage and Drainage District Environmental Management and Quality Control Annual Report). The temperature of the eastern boundary current passing by the Iona outfall is expected to reflect the water temperature in Haro Strait with a delay of about 1 month (S. Stevens; pers. comm.). The temperature measured at Station S4-1.5, however, is less predictable because of turbulent mixing between the incoming water associated with the boundary current and “older” waters that resided in the SoG for variable periods of time. If the water sampled at Station S4-1.5 is directly fed by the boundary current, its PBDE concentration is expected to be relatively high, since this water has recently received contaminants discharged by the Iona outfall. On the other hand, if the sampled water has resided in the SoG for a longer period, it is expected to have lower PBDE concentration because of mixing and removal by particle scavenging. The total quantifiable dissolved PBDE concentration measured between 40 and 80 m depth (i.e. the depth interval within the intermediate layer where the Iona plume is expected to be found) at Station S4-1.5 ranges from 56 pg/L (September 2017; 57 m) to 978 pg/L (February 2017; 50-60 m). In order to verify whether the relatively large variations in PBDE concentration measured at S4-1.5 could be related to the “age” of the intermediate water (here “young” water means water that has recently entered the SoG from Haro Strait, while “old” water means water that has resided for some time in the SoG), the temperature record measured at the Ocean Networks Canada East node was used to establish the temperature of “old” and “new” water, which can then be compared to the temperature at 170 m at S4-1.5 at the time of sampling (Figure 3.20). The ONC East node is situated south of the Iona outfall at a location where bottom water oscillates between the new incoming and the old outgoing water so that the node records the temperature of the two water masses through time (dark blue line on Figure 3.20b). The 73 outward envelop of the ONC data shows the seasonal temperature changes of the incoming “new” water reaching the maximum temperature at the end of summer and minimum temperature at the end of winter with a relatively large amplitude (light blue line on Figure 3.20b). In contrast, the temperature oscillation of the outgoing “old” water has a lower amplitude, due to mixing, and the maxima/minima are delayed by several months, reflecting the residence time of this water in the SoG (red line on Figure 3.20b). This produces a temperature contrast between “new” and “old” water over most of the year, except in early summer and early winter when both water masses have a similar temperature. Measuring temperature at 170 m depth at the sampling station (red circles on Figure 3.20b) thus indicates whether the water sampled in the intermediate layer (ca. 50 – 150 m depth) was “new”, i.e. coming from the south and having passed by the Iona outfall recently, or “old”, i.e. coming from the north and having been out of contact with the Iona outfall for several months. When concentrations are relatively high, as in February 2017 (978 pg/L at 50-60 m) and May 2017 (473 pg/L at 64 m), the temperature at S4-1.5 does indicate the presence of “new” intermediate water. On the other hand, the much lower concentrations measured in September 2017 (56 pg/L at 57 m) and January 2018 (98 pg/L at 73 m) coincide with “old” intermediate water (Figure 3.20b). In April 2018, there was a peak concentration (263 pg/L) at 59 m when temperature suggests mostly new water, and in August 2018, the concentration at 70 m dropped to 128 pg/L when temperature suggested a mix between old and new water. The variations in dissolved PBDE concentration in the intermediate water at Station S4-1.5 can thus be largely explained by the fact that the Iona effluent is not homogeneously mixed in the southern SoG and is often consistent with a sampling of “old” vs “new” water. The comparatively high total dissolved PBDE concentration measured at Station S2 at ca. 50 m depth (Table 3.4a) suggest that sampling at this station, which is located on the eastern side of the southern SoG (Figure 1.2), always occurred in “new” water. Unfortunately, this cannot be corroborated by temperature, as done for S4-1.5, because sampling was done in early winter, when the temperature difference between “new” and “old” water is very small. 74 3.2.6.2 Surface water (0 – 50 m) Relatively high total dissolved PBDE concentrations were found at 31 m in September 2017 and at 26 m and 54 m in August 2017 (Figure 3.20a). These concentration maxima occurred at the end of summer, when the Iona effluent plume was expected to reach its trapping depth in deeper water, within the intermediate layer. In addition, the dissolved PBDE concentration measured in intermediate water at these times were relatively low and consistent with the presence of “old” water in this depth interval. This contrast seems to indicate that the dissolved PBDE measured at the end of summer had been added to the surface layer and was mixed in the surface layer of the SoG, independently of the intermediate layer. As already indicated in the previous section, the source of this PBDE is unclear. If it came from the Iona outfall, the effluent plume would have had to rise above the intermediate layer at a time when the trapping depth in the IDZ is significantly deeper. If it came from the much smaller Lion’s gate wastewater outfall, it would have required limited mixing within the surface layer. The high surface concentration measured in April 2018 poses a similar conundrum. 3.2.6.3 Deep water (> 200 m) Water below 250 m was analyzed five times (Figure 3.20a). Even though the sampling depth was well below the point of discharge of the Iona outfall, total dissolved PBDE concentrations were relatively high, ranging from a minimum of 68 pg/L in January 2018 to a maximum of 400 pg/L in August 2018 (Figure 3.22). At this point, the database is too parse to clearly establish the processes responsible for the relatively high and variable concentrations measured in deep water. As discussed in the previous section, vertical mixing cannot explain these high concentrations, which leads to invoking reversible scavenging on settling particles, i.e. adsorption on the surface of particles as they sink through the intermediate layer and desorption in deep water as a result of the decomposition of organic matter in particles, which is more likely to adsorb PBDE on account of their lipophilic properties. Such process would be expected to be less important in winter when phytoplankton growth is minimal, which is at least consistent with the trend in the data (Figure 3.22). Higher concentrations at the end of summer could also be a result of deep water renewal events, which occurred between May and September 2017, and between April and August 2018 (Figure 3.23). Cascading of dense water into the deep basin of 75 the SoG causes resuspension of PBDE contaminated sediments, which could possibly release fine (< 2.2 μm) particles in the deep SoG, which would be measured as “dissolved” by our sampling method. Figure 3.22: Total quantifiable dissolved PBDE concentration measured in deep water at Station S4-1.5 (depth of sampling indicating above each bar). BDE-206 to 209 are not included in the concentrations above. Figure 3.23: Bottom current speed (green curves) and seawater densities (red curves) at Ocean Networks Canada’s central node (49.0423°N, 123.3171°W, water depth 300 m; Ocean Networks Canada) in the Strait of Georgia in 2017 (A) and 2018 (B) (Kuang, 2019). Grey areas and arrows represent periods of weak tidal mixing based on tidal predictions and deep water renewal seasons, respectively. The positive and negative values of current speed is caused by the direction. 76 3.2.7 Fractionation between congeners in the water column of the SoG The large difference in PBDE partitioning between the “dissolved” and “particulate” phase (as empirically defined in this study) in effluent and seawater has been used to support the hypothesis that PBDEs desorb from sewage particles during their dispersion in seawater (Section 3.2.3). This hypothesis was further validated by the congener fractionation occurring during this apparent desorption, which ruled out the possibility of forming the “dissolved” PBDE fraction in seawater by fragmentation of sewage particles into particles smaller than the pore size (2.2 μm) of the filters used to differentiate between the two phases. Congener fractionation is also observed in the vertical dissolved PBDE profiles measured at Station S4-1.5 and when comparing congener distribution at different stations in the Salish Sea, further supporting the desorption hypothesis. 3.2.7.1 Vertical congener fractionation at Station S4-1.5 Fractionation between congeners was particularly well expressed in the depth profiles measured in May 2017 and January 2018 (Figure 3.4). As the effluent plume rose following its discharge from the Iona diffusers, the less brominated PBDEs desorbed faster from the sewage particles and, therefore at greater depth, while the more hydrophobic and brominated congeners desorbed at slower rates and at shallower depths. In May 2017, tri-brominated congener concentrations (BDE-17+25, -28+33) showed a broader and deeper peak below 60 m, tetra (BDE-47, -49) and penta (BDE-99, -100) -brominated congeners showed sharper peaks at ca. 60 m, which could not be differentiated because of low sampling resolution, while hexa-brominated congeners (BDE-153, -154) reached maximum concentrations at ca. 45 m. A similar trend was observed in January 2018, when concentrations were much lower. The relatively high concentration of tri-brominated congeners at a depth greater than the deepest Iona diffusers could be explained by vertical mixing during transit. Congener fractionation was less obvious in the other profiles. As already discussed, PBDE concentrations in the intermediate water were relatively low in September 2017 and August 2018, consistent with the temperature signal indicating the presence of “old” intermediate water. However, higher concentrations were found in the surface layer (Figure 3.20a), whose origin is unclear (Section 3.2.6.2). The congener profiles measured in September 77 2017 are all very similar (Figure 3.24), indicating little fractionation. This also applies to the profiles in August 2018. Figure 3.24: Depth profiles of the concentration of dissolved congeners with increasing degree of bromination measured at S4-1.5 in (a) September 2017 and (b) August 2018. 78 However, plotting profiles of congener concentration ratios showed evidence for subtler fractionation (Figure 3.25a). In September, congener concentrations normalized to tetra-brominated BDE-47 concentration clearly indicated that the PBDEs in the peak concentration at ca. 30 m were comparatively depleted in tri-brominated congeners and enriched in penta-brominated congeners. Burrard Inlet has been identified as a potential source of PBDE in the SoG, which would be largely confined to the surface layer. Comparing the same ratios measured in Burrard Inlet (Station S3; Figure 3.25), suggests that the latter may be the source of the relatively high PBDE concentration observed in the surface layer at Station S4-1.5 in September 2017, although that would require the loss of tri- and hexa-brominated congeners during transit, possibly through evaporation from the warm summer surface water and particle scavenging, respectively. A similar explanation could also be advanced to explain the surface concentration maximum observed in April 2018. While plausible, these ad hoc explanations are very speculative. Nonetheless, they further support the systematic fractionation of PBDE congeners by a suite of environmental physicochemical processes such as desorption from contaminated particles, adsorption on marine particles, reversible scavenging, and air-sea exchange. Fractionation during desorption from sewage particles is also supported by comparing congener concentration ratios measured in the effluent plume (Station S1) and S4-1.5 (Figure 3.25). Tri-brominated to BDE-47 ratios are higher in the plume, reflecting the faster desorption of the less brominated homologs from sewage particles, while penta- and hexa-brominated homolog ratios are lower in the plume, reflecting their much slower desorption. Fully predicting the behavior of PBDEs in the environment will require quantifying adsorption, desorption and scavenging rates, as well as air-sea exchange, and embedding these processes in a circulation model. 79 (a) 80 (b) 81 Figure 3.25: Depth profiles of the concentration ratios of quantifiable dissolved congeners with increasing degree of bromination to BDE-47 measured at S4-1.5 in (a) September 2017, (b) August 2018, and (c) April 2018. Ratios measured at Station S3 (blue diamonds) and S1 (red stars) are also shown. The depth of S1 and S3 are shifted for easier comparison. (c) 82 3.2.7.2 Spatial congener fractionation in the Salish Sea As already indicated, the total quantifiable dissolved PBDE concentrations at Station NG, HS and JF2 are much lower than at Station S4-1.5 and S2 (ca. < 10 pg/L vs. 300 pg/L), indicating either dilution of PBDE discharged with the Iona effluent by Pacific water entering the SoG through Juan de Fuca and Haro Strait or removal to the sediment by scavenging on settling particles. Congener distribution provides a means of distinguishing between these two possibilities. The average dissolved BDE-28+33/BDE-47 concentration ratio at Station NG was 0.11 ± 0.02 (1 stdev), which is similar to the ratios measured in Haro Strait (0.11) and Juan de Fuca Strait (0.09) (Table 3.8a). These ratios were significantly higher than the average ratio measured in the 30 samples at Station S4-1.5 (0.034 ± 0.008, Table 3.6a). Considering that the PBDE concentrations of incoming Pacific waters are nearly zero and much lower than the concentrations measured at S4-1.5, if the drop in dissolved PBDE concentrations between S4-1.5 and Stations NG, HS and JF2 were due to dilution by Pacific water only, the BDE-28+33/BDE-47 ratio would not have changed between S4-1.5 and the other stations. Instead, the increase in ratio at NG, HS and JF2 implies that a larger fraction of the BDE-47 has been preferentially removed from the water column by scavenging into the underlying sediments during transit from the southern SoG. Considering that the average dissolved concentration in seawater at Station S4-1.5 is: [BDE-28+33] = 4.9 pg/L [BDE-47] = 153 pg/L and the average concentration at Station NG and HS is [BDE-28+33] = 0.63 pg/L [BDE-47] = 5.9 pg/L Taking the concentration measured in the deep layer of Juan de Fuca Strait as the Pacific end-member: [BDE-28+33] = 0.19 pg/L [BDE-47] = 2.0 pg/L Assuming that the drop in [BDE-28+33] from S4-1.5 to NG or HS is entirely due to mixing, we can calculate the fraction of S4-1.5 water present in Haro Strait or the northern SoG: 83 (4.9f) +(0.19(1-f)) = 0.63 f = 0.093 where f is the fraction of S4-1.5 water at Station NG or HS, and we can predict the [BDE-47] at these stations if this congener concentration were similarly entirely controlled by mixing: (0.093 x 153 pg/L) + (0.907 x 2.0 pg/L) = 16.1 pg/L Since only 5.9 pg/L of BDE-47 were found on average at Station NG and 6.1 pg/L at HS, 10 pg/L of BDE-47 (i.e. 62% of BDE-47 found at S4-1.5) must have been removed during transit from S4-1.5 to NG/HS. This must be viewed as a minimum since the calculation assumes that BDE-28+33 is not removed at all by scavenging. Mass balance calculation based on salinity distribution indicates that Haro Strait water consists of 60% southern SoG water and 40% Juan de Fuca Strait water, instead of the ca. 10% SoG, ca. 90% JdF estimated above when assuming conservative mixing of BDE-28+33. This implies that ca. 50% of the BDE-28+33 has also been removed by scavenging during transit, and the actual extent of BDE-47 removal by scavenging is 94%. Percent removal for the more brominated congeners is expected to be larger, explaining their undetectable levels outside the southern SoG. The spatial evolution of the dissolved BDE-28+33/BDE-47 concentration ratio is consistent with the working hypothesis proposed at the beginning of this chapter (Figure 3.26). The concentration ratio of the two PBDE congeners was 0.043 and 0.039 in the Iona effluent plume (S1) and in the Inner Harbor of Burrard Inlet (S3), respectively. These ratios were found in seawater containing recently discharged sewage particles that more rapidly desorbed the tri-brominated congener. The ratios measured in the middle of the southern SoG (Station S4-1.5) were generally lower (0.034 ± 0.008), reflecting the more gradual desorption of the tetra-brominated congener from sewage particles. The total dissolved PBDE concentration at these three sites was relatively high (Table 3.13), indicating that scavenging of desorbed congeners was not yet substantial. Moving to stations where total dissolved PBDE concentrations were increasingly low (Station S3b and NG/HS), the ratio gradually increased, reflecting the preferential scavenging of BDE-47 by marine particles. 84 Figure 3.26: Dissolved BDE-28+33/BDE-47 concentration ratio (w/w) measured in the Iona effluent plume (S1) and in the Inner Harbor of Burrard Inlet (S3), in the southern SoG (S4-1.5), in the Central Harbor of Burrard Inlet (S3b), and in the northern SoG (NG) and Haro Strait (HS). Data in Table 3.6a, Table 3.8a, and Table 3.11a. 3.2.8 Mass balance and box model simulation for PBDEs The Salish Sea Box Model was used to investigate the processes that control the concentrations of dissolved PBDEs in SoG (Wang et al., 2019). Since BDE-209, the most important and most widely applied congener, is not measurable in the Fraser River and the Pacific Ocean, the model is only used for BDE-47 and 99. The Pacific Ocean input was set to reproduce the concentrations measured in the lower Juan de Fuca Strait box. The Vancouver WWTP and Victoria WWTP inputs are taken from the literature (Dinn et al., 2012b) and added to the lower SoG and lower Haro Strait box, respectively (Figure 2.2). Detailed input settings for the model are shown in Table 3.15. Although the Fraser River cannot contribute to the high dissolved PBDE concentrations measured in surface water at Stn 4-1.5, the average daily discharge in June and February for total BDE-47, 99, 153 and 209 (Table 3.16) are similar to the discharge rate from the Iona outfall 85 (Table 3.17) (Dinn et al., 2012b). This suggests that Fraser River contributes significantly to the total amount of PBDEs in the Strait of Georgia. However, this still cannot explain the increasing dissolved PBDE concentrations towards the surface due to the low PBDE concentrations in the Fraser River and further suggests atmospheric deposition. The modelled results of dissolved concentrations in Haro Strait and Strait of Juan de Fuca are comparable to what we actually measured (Table 3.18; Figure 3.27), but there is a considerable discrepancy between the results for the upper and lower SoG boxes. This is all the more serious when considering that the box model does not include any PBDEs removal to the sediment by scavenging and we would thus expect higher modeled concentrations than measured. One possible explanation stems from the fact that the water in SoG is not well mixed, and the dissolved PBDEs concentrations are not uniform in the SoG, so that dissolved concentration measured at S4-1.5 is not representative of the entire SoG. For instance, the northern SoG has much lower dissolved PBDE concentrations than that at S4-1.5. Since the concentrations of dissolved PBDEs were measured in the southern and northern SoG, it is possible to figure out the volume of both types of water required to match the average SOG concentrations predicted by the model based on mass balance: the total volume of central and northern SoG equals the total SoG volume, and the sum of PBDEs in central and northern SoG equal to the PBDEs in the entire SoG based on the modelled result. �𝑉𝑉𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 ∗ [𝐵𝐵𝐵𝐵𝐵𝐵]𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 = 𝑉𝑉𝑁𝑁𝑁𝑁 ∗ [𝐵𝐵𝐵𝐵𝐵𝐵]𝑁𝑁𝑁𝑁 + 𝑉𝑉𝑠𝑠𝑚𝑚𝑠𝑠𝑠𝑠ℎ𝑚𝑚𝑒𝑒𝑒𝑒 ∗ [𝐵𝐵𝐵𝐵𝐵𝐵]𝑠𝑠𝑚𝑚𝑠𝑠𝑠𝑠ℎ𝑚𝑚𝑒𝑒𝑒𝑒𝑉𝑉𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 = 𝑉𝑉𝑁𝑁𝑁𝑁 + 𝑉𝑉𝑠𝑠𝑚𝑚𝑠𝑠𝑠𝑠ℎ𝑚𝑚𝑒𝑒𝑒𝑒 where 𝑉𝑉𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚, 𝑉𝑉𝑁𝑁𝑁𝑁 , and 𝑉𝑉𝑠𝑠𝑚𝑚𝑠𝑠𝑠𝑠ℎ𝑚𝑚𝑒𝑒𝑒𝑒 represent the volume of water in the entire SoG (600 km3; Wang et al., 2019), the northern SoG and southern SoG, respectively. [𝐵𝐵𝐵𝐵𝐵𝐵]𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚, [𝐵𝐵𝐵𝐵𝐵𝐵]𝑁𝑁𝑁𝑁, and [𝐵𝐵𝐵𝐵𝐵𝐵]𝑠𝑠𝑚𝑚𝑠𝑠𝑠𝑠ℎ𝑚𝑚𝑒𝑒𝑒𝑒 represent the modelled concentrations in the entire SoG from the box model, the actual concentrations measured in northern SoG and southern SoG, respectively. Thus, For BDE-47 �600 𝑘𝑘𝑚𝑚3 ∗ 6.5 𝑝𝑝𝑔𝑔/𝐿𝐿 = 𝑉𝑉𝑁𝑁𝑁𝑁 ∗ 5.87 𝑝𝑝𝑔𝑔/𝐿𝐿 + 𝑉𝑉𝑠𝑠𝑚𝑚𝑠𝑠𝑠𝑠ℎ𝑚𝑚𝑒𝑒𝑒𝑒 ∗ 153 𝑝𝑝𝑔𝑔/𝐿𝐿600 𝑘𝑘𝑚𝑚3 = 𝑉𝑉𝑁𝑁𝑁𝑁 + 𝑉𝑉𝑠𝑠𝑚𝑚𝑠𝑠𝑠𝑠ℎ𝑚𝑚𝑒𝑒𝑒𝑒 solving the equation yields 𝑉𝑉𝑠𝑠𝑚𝑚𝑠𝑠𝑠𝑠ℎ𝑚𝑚𝑒𝑒𝑒𝑒 = 2.6 𝑘𝑘𝑚𝑚3 and 𝑉𝑉𝑁𝑁𝑁𝑁 = 597.4 𝑘𝑘𝑚𝑚3. Thus, 𝑉𝑉𝑠𝑠𝑚𝑚𝑠𝑠𝑠𝑠ℎ𝑚𝑚𝑒𝑒𝑒𝑒/𝑉𝑉𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 is 0.4%. 86 For BDE-99, �600 𝑘𝑘𝑚𝑚3 ∗ 6.5 𝑝𝑝𝑔𝑔/𝐿𝐿 = 𝑉𝑉𝑁𝑁𝑁𝑁 ∗ 0 𝑝𝑝𝑔𝑔/𝐿𝐿 + 𝑉𝑉𝑠𝑠𝑚𝑚𝑠𝑠𝑠𝑠ℎ𝑚𝑚𝑒𝑒𝑒𝑒 ∗ 153 𝑝𝑝𝑔𝑔/𝐿𝐿600 𝑘𝑘𝑚𝑚3 = 𝑉𝑉𝑁𝑁𝑁𝑁 + 𝑉𝑉𝑠𝑠𝑚𝑚𝑠𝑠𝑠𝑠ℎ𝑚𝑚𝑒𝑒𝑒𝑒 solving the equation yields 𝑉𝑉𝑠𝑠𝑚𝑚𝑠𝑠𝑠𝑠ℎ𝑚𝑚𝑒𝑒𝑒𝑒 = 25.5 𝑘𝑘𝑚𝑚3 and 𝑉𝑉𝑁𝑁𝑁𝑁 = 574.5 𝑘𝑘𝑚𝑚3 . Thus, 𝑉𝑉𝑠𝑠𝑚𝑚𝑠𝑠𝑠𝑠ℎ𝑚𝑚𝑒𝑒𝑒𝑒/𝑉𝑉𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 is 4.3%. These results indicate that the volume of the “southern” SoG water, as measured at S4-1.5, could only represent water occupying a few percent of the total water volume of the SoG, which cannot be true. There are other ways to reconcile the discrepancy between observations and model. First, the dissolved PBDE concentrations we measured could be too high because of contamination during sampling. This is unlikely considering the procedural blanks (Table 3.2a). and the oceanographic consistency of the data. Second, there may be additional and unknown sources of PBDE to the SoG. These sources may include, but are not limited to, urban run-off, atmospheric deposition, and other input sources that have not yet been investigated (e.g. Lion’s Gate WWTP, CSO, SSO). Third, we may underestimate the input from the Iona outfall, either because of increasing effluent concentrations in recent years (model input is based on 2004 effluent concentration data) or because of analytical problems in the analysis of PBDE concentration in WWTP effluent (e.g. overestimation of recovery because the 13C-congener spikes were not fully equilibrated with the sample before extraction). The last three possibilities need further investigation. 87 Figure 3.27: Modelled results for BDE-47 and BDE-99 between 2017 and 2019. SoGu and SoGl represent upper and lower Strait of Georgia, respectively. HSu and HSl represent upper and lower Haro Strait, respectively. JdFSu and JdFSl represent upper and lower Juan de Fuca Strait, respectively. 88 Table 3.1: Laboratory analysis blanks reported by AXYS for different batches of dissolved (a) and particulate (b) PBDE analysis. Dates are sampling times of samples included in each batch of analysis. Grey cells are data more than 1.5 interquartile range either below the first quartile or above the third quartile, which are considered outliers and removed before calculating LoD and LoQ. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). (a) Sampling Date Oct 2013 Dec 2013 Oct/Dec 2014 Dec 2015 Feb/May 2017 Jun 2017 Aug 16/Sep 17/ Jan/Feb 18 Apr/Aug/ Sep 18 Aug 2018 Average (w/o outlier) LoD LoQ Axys ID WG45312-101 WG46585-101 L WG49873-101 i WG54477-101 WG59905-101 WG61733-101 RX WG63110-101 i2 WG66479-101 WG66480-101 UNITS pg pg pg pg pg pg pg pg pg pg pg pg BDE-7 2.8 14 2.7 2.7 6 5.2 3.8 2 5.7 4 5 15 BDE-8 + 11 2.2 11 2 2.1 4 4 2.9 2 4.4 3 3 11 BDE-10 3.2 16 3.5 3.1 7 6 4.4 2 5.7 4 5 17 BDE-12 + 13 2 9.6 2 2.1 4 3.5 2.5 2 3.8 3 2 8 BDE-15 2 8.3 2 2.17 3 2.9 2.1 2 3.2 2 2 5 BDE-17 + 25 3.34 12 4.04 3.5 6 10 7 2 4.7 6 10 33 BDE-28 + 33 4.38 11.9 5.11 6.33 6 5.42 6.4 2.04 4.2 5 4 15 BDE-30 2 12 2.3 3.7 3 3.3 7.8 2 4.6 5 10 33 BDE-32 2 9.7 2 3 3 2.5 540 2 3.7 3 8 26 BDE-35 2 8.4 2 2.3 2 2.1 4.8 2 3.8 3 3 11 BDE-37 7.34 9.55 2 29.2 5 2.1 5.79 2 26.1 10 31 104 BDE-47 118.2 185 98.6 290 200 70.3 29.4 98.5 233 147 254 847 BDE-49 3.84 15 6.32 8.07 8 5.09 4.8 4.63 11.6 7 11 37 BDE-51 2 9.8 2 4.9 2 2.2 3.2 2 2 3 3 10 BDE-66 3.88 19 2.2 8.1 7 5.42 5.4 3.11 12.9 7 16 54 BDE-71 2 14 5.7 7.5 6 3.2 5.1 2 2.86 4 6 20 BDE-75 2 13 2 5.8 2 2.4 4 2 2 4 11 37 BDE-77 2 12 2 4.7 2 2.1 3.2 2 2 3 3 10 89 Sampling Date Oct 2013 Dec 2013 Oct/Dec 2014 Dec 2015 Feb/May 2017 Jun 2017 Aug 16/Sep 17/ Jan/Feb 18 Apr/Aug/ Sep 18 Aug 2018 Average (w/o outlier) LoD LoQ Axys ID WG45312-101 WG46585-101 L WG49873-101 i WG54477-101 WG59905-101 WG61733-101 RX WG63110-101 i2 WG66479-101 WG66480-101 BDE-79 2.38 13 2 5.3 2 3.3 3.7 2 2.97 3 3 11 BDE-85 5.68 14 7.16 12.1 10 7.27 3.5 4.23 6.86 8 10 35 BDE-99 126.6 147 95.7 238 211 73.4 27.9 84.3 204 134 214 714 BDE-100 25.2 35.4 19.4 54.3 46 19.8 6.99 21.1 51.4 31 50 165 BDE-105 2 19 2.5 4.8 14 6.97 4.6 2 2 6 18 61 BDE-116 2 22 3 7.1 8 8.8 6.5 2 2 5 9 29 BDE-119 + 120 2 13 2 4.1 5 6.93 4.1 2 2.92 4 5 17 BDE-126 2 9.4 2 2.5 3 2.4 2.3 2 2 2 1 4 BDE-128 2 23 4 9.4 28 24 22 2 2.58 13 33 110 BDE-138 + 166 6.12 27 5.2 8.7 16 20 12 2.25 3.53 11 25 83 BDE-140 2.5 16 2.8 5.7 10 10 8.2 2 2 7 15 49 BDE-153 13.28 20 8.95 22.2 20 14.1 9.9 5.29 11.7 14 17 57 BDE-154 6.98 11.4 6.59 14.2 19 17.5 5.7 4.45 9.95 11 16 52 BDE-155 2 9.7 2.28 4.28 8 12 6.2 2 2 5 11 38 BDE-181 2 35 5.4 15 20 7.82 6.5 2 2 11 33 110 BDE-183 8.92 20.9 16.6 17.9 13 14.9 3.8 5.36 2.33 12 20 67 BDE-190 2.6 64 9.7 27 37 11 12 2 2.2 19 62 208 BDE-203 9.12 83 7.9 33.2 16 31 7.2 5.23 3 14 35 118 BDE-206 87.4 190 63.7 294 128 96.4 15 24.7 32.1 103 271 904 BDE-207 134.8 170 115 422 256 200 21 57.6 15 155 387 1288 BDE-208 71.6 200 77.2 202 133 164 36 24.4 16 103 222 739 BDE-209 822 1000 760 3700 2280 1670 190 300 328 1228 3453 11509 90 (b) Sampling Date Oct 2013 Dec 2013 Oct/Dec 2014 Dec 2015 May 2017 Sep 17/Jan 18 Apr/Aug 2018 Average (w/o outlier) LoD LoQ Axys ID WG45378-101 WG46128-101 i WG49872-101 K WG54476-101 WG61029-101 WG63098-101 WG66478-101 UNITS pg pg pg pg pg pg pg pg pg pg BDE-7 5.36 2.9 2.1 2.5 2 1.4 1 2 2 7 BDE-8 + 11 4.08 2.2 2 2.1 1 1.1 1 2 2 6 BDE-10 6.08 3.6 2.4 3 2 3.44 1 3 5 16 BDE-12 + 13 3.52 3.21 2 2.1 1 1 1 2 3 10 BDE-15 2.96 1.64 2 2.1 1 1 1 2 2 7 BDE-17 + 25 2.4 5.82 2 3.8 3 2.5 1 3 5 15 BDE-28 + 33 2.4 10.3 2 3.4 2 2.4 1 2 2 8 BDE-30 2.4 4.5 2 4 1 2.8 1 3 4 14 BDE-32 2.4 3.4 2 3.2 1 2.2 1 2 3 9 BDE-35 2.4 2.6 2 2.5 1 1.7 1 2 2 7 BDE-37 12.8 4.18 3.12 17.5 1 2.28 11.9 8 19 64 BDE-47 53.6 244 38.9 37 33 22.7 17.1 34 39 129 BDE-49 2.4 12.8 2 6.8 1 1.8 1.33 4 13 43 BDE-51 2.4 4.1 2 4.6 1 1.2 1 2 4 15 BDE-66 2.4 6.56 2.2 7.5 1 1.9 1 3 8 27 BDE-71 2.4 6 4.15 6.9 1 1.7 1 3 7 24 BDE-75 2.4 4.4 2 5.3 1 1.4 1 3 5 17 BDE-77 2.4 4 2 4.2 1 1.2 1 2 4 14 BDE-79 2.4 3.9 2 4.9 1 1.3 1 2 5 15 BDE-85 2.4 15 2 3 1 1.7 1.16 2 2 8 BDE-99 45.6 249 29.3 30.3 24 9.77 14.9 26 38 127 BDE-100 11.2 44.5 6.41 6.17 7 4.6 3.17 6 8 27 BDE-105 2.4 22 2 4 1 2.2 1 2 3 11 BDE-116 2.4 33 2 5.9 1 3.1 1 3 5 18 BDE-119 + 120 2.4 18 2 3.5 1 1.9 1 2 3 9 91 Sampling Date Oct 2013 Dec 2013 Oct/Dec 2014 Dec 2015 May 2017 Sep 17/Jan 18 Apr/Aug 2018 Average (w/o outlier) LoD LoQ Axys ID WG45378-101 WG46128-101 i WG49872-101 K WG54476-101 WG61029-101 WG63098-101 WG66478-101 BDE-126 2.4 9.8 2 2.1 1 1.2 1 2 2 6 BDE-128 2.4 8.4 14.4 5.4 1 9.1 9.6 7 14 45 BDE-138 + 166 2.4 6.9 4.7 9.1 4 5.4 4.2 5 7 22 BDE-140 2.4 4.4 3.1 6 1 3.5 2.7 3 5 15 BDE-153 4.8 23.2 4 7.1 2 4.4 3.1 4 5 17 BDE-154 5.6 17.4 3.56 3.8 4 2.5 1.8 3 4 13 BDE-155 2.4 3.56 2.1 4.1 1 2.6 2.1 3 3 10 BDE-181 2.4 14 3.8 25 1 4.1 1 7 27 90 BDE-183 4.8 6.9 2.1 15 1 4.54 1.34 5 15 49 BDE-190 2.4 24 7 44 2 7.7 1 13 48 160 BDE-203 9.6 49 5.5 25 1 4.3 3.92 14 52 173 BDE-206 56 190 28.3 80 30 15.7 18.8 38 75 249 BDE-207 63.2 200 29 87 52 15.6 25.4 45 81 270 BDE-208 44 230 28 95 33 19 13.6 39 89 295 BDE-209 389.6 2700 274 513 304 136 104 287 462 1539 92 Table 3.2: (a) Laboratory procedural blanks for dissolved PBDEs; (b) at sea procedural blank for dissolved PBDEs; (c) laboratory procedural blank for particulate PBDEs. The reported values have been corrected for laboratory analysis blanks of the corresponding sample batch (Table 3.1). Numbers in italics are above LoD but below LoQ. Bold numbers indicate values above LoQ. Empty cells indicate that blank-corrected values were below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). (a) Date LoD LOQ Dec 2013 May 2017 May 2017 Sample Name Lab. Procedural blank Niskin-Silicon Tubing Niskin-Metal Spring UNITS pg pg pg pg pg BDE-28 + 33 4 15 5 BDE-183 20 67 41 BDE-209 3453 11509 5580 (b) Date LoD LOQ Aug 2018 Aug 2018 Aug 2018 Aug 2018 Aug 2018 Aug 2018 Aug 2018 Sample Name At Sea Procedural Blank NG 0m NG 25m NG 50m NG 75m NG 150m NG 330m UNITS pg pg pg pg pg pg pg pg pg BDE-15 2 5 16 12 8 7 6 4 8 BDE-17 + 25 10 33 153 66 44 36 26 26 49 BDE-28 + 33 4 15 315 101 77 88 61 55 110 BDE-47 254 847 5047 1202 711 647 456 528 1112 BDE-49 11 37 115 42 25 25 15 16 35 BDE-51 3 10 37 7 4 5 3 7 BDE-66 16 54 87 27 19 BDE-71 6 20 16 BDE-99 214 714 490 93 Date LoD LOQ Aug 2018 Aug 2018 Aug 2018 Aug 2018 Aug 2018 Aug 2018 Aug 2018 Sample Name At Sea Procedural Blank NG 0m NG 25m NG 50m NG 75m NG 150m NG 330m BDE-100 50 165 217 52 BDE-126 1 4 1 (c) Date LoD LOQ Dec 2013 Sample Name Lab. Procedural Blank UNITS pg pg pg BDE-206 75 249 240 BDE-207 81 270 373 BDE-208 89 295 145 BDE-209 462 1539 4610 94 Table 3.3: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PBDE congeners in SoG seawater at Station S2. Quantifiable congeners are in bold. Detectable congeners, below LoQ but above LoD, are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). Particulate BDE-209* has been corrected for the procedural blank (Table 3.2c). (a) Date LoQ 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth 45-55 m 50 m 55-65 m Volume sampled 111.0 L 100.6 L 125.5 L UNITS pg pg pg pg BDE-7 15 11 5 BDE-8 + 11 11 6 5 BDE-15 5 35 40 23 BDE-17 + 25 33 497 284 174 BDE-28 + 33 15 930 527 378 BDE-47 847 21015 12401 15210 BDE-49 37 664 510 364 BDE-51 10 151 92 66 BDE-66 54 336 333 288 BDE-71 20 75 68 57 BDE-75 37 24 33 26 BDE-79 11 21 14 BDE-85 35 128 234 409 BDE-99 714 4193 7034 11462 BDE-100 165 1245 1791 2706 BDE-105 61 40 BDE-116 29 51 22 BDE-119 + 120 17 55 39 BDE-126 4 2 24 8 BDE-128 110 416 BDE-138 + 166 83 74 91 BDE-140 49 45 28 BDE-153 57 83 696 956 BDE-154 52 107 490 850 BDE-155 38 45 67 BDE-183 67 129 110 BDE-203 118 117 137 BDE-206 904 1256 BDE-207 1288 1435 95 Date LoQ 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth 45-55 m 50 m 55-65 m Volume sampled 111.0 L 100.6 L 125.5 L UNITS pg pg pg pg BDE-208 739 1153 258 BDE-209 11509 4080 9340 13300 (b) Date LoQ 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth 55 m 48 - 52 m 55 m Volume filtered 561.8 L 711.3 L 163.1 L UNITS pg pg pg pg BDE-47 129 147 BDE-99 127 131 BDE-100 27 40 BDE-128 45 19 50 BDE-138 + 166 22 12 13 BDE-140 15 7 8 BDE-153 17 21 BDE-154 13 4 21 BDE-155 10 4 5 BDE-183 49 20 BDE-203 173 188 BDE-206 249 2380 BDE-207 270 5340 91 BDE-208 295 3650 BDE-209 1539 43100 480 BDE-209* 1539 38490 - 96 Table 3.4: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PBDE congeners concentrations (pg/L) in SoG seawater at Station S2. Quantifiable congeners are in bold. Detectable congeners, below LoQ but above LoD, are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). BDE-209* has been corrected for the procedural blank (Table 3.2c). (a) Date 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth 45-55 m 50 m 55-65 m Volume sampled 111.0 L 100.6 L 125.5 L UNITS pg/L pg/L pg/L BDE-7 0.11 0.04 BDE-8 + 11 0.06 0.04 BDE-15 0.32 0.39 0.18 BDE-17 + 25 4.5 2.8 1.4 BDE-28 + 33 8.4 5.2 3.0 BDE-47 189 123 121 BDE-49 6.0 5.1 2.9 BDE-51 1.4 0.91 0.52 BDE-66 3.0 3.3 2.3 BDE-71 0.67 0.68 0.45 BDE-75 0.21 0.32 0.21 BDE-79 0.19 0.14 BDE-85 1.2 2.3 3.3 BDE-99 37.8 69.9 91.3 BDE-100 11.2 17.8 21.6 BDE-105 0.39 BDE-116 0.51 0.17 BDE-119 + 120 0.54 0.31 BDE-126 0.01 0.24 0.06 BDE-128 4.1 BDE-138 + 166 0.73 0.72 BDE-140 0.45 0.22 BDE-153 0.75 6.9 7.6 BDE-154 0.96 4.9 6.8 BDE-155 0.45 0.54 BDE-183 1.3 0.88 BDE-203 1.2 1.1 BDE-206 12.5 97 Date 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth 45-55 m 50 m 55-65 m Volume sampled 111.0 L 100.6 L 125.5 L UNITS pg/L pg/L pg/L BDE-207 14.3 BDE-208 11.5 2.06 BDE-209 36.8 92.8 106 (b) Date 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth 55 m 48 - 52 m 55 m Volume filtered 561.8 L 711.3 L 163.1 L UNITS pg/L pg/L pg/L BDE-47 0.21 BDE-99 0.18 BDE-100 0.056 BDE-128 0.033 0.070 BDE-138 + 166 0.022 0.019 BDE-140 0.012 0.011 BDE-153 0.030 BDE-154 0.007 0.029 BDE-155 0.006 0.007 BDE-183 0.035 BDE-203 0.33 BDE-206 4.24 BDE-207 9.51 0.13 BDE-208 6.50 BDE-209 76.7 2.94 BDE-209* 68.5 - 98 Table 3.5: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PBDE congeners in SoG seawater at Station S4-1.5. Quantifiable congeners are in bold. Detectable congeners, below LoQ but above LoD, are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). Particulate BDE-209* has been corrected for the procedural blank (Table 3.2c). (a) Date LoQ 14-Feb-2017 14-Feb-2017 9-May-2017 09-May-2017 09-May-2017 09-May-2017 09-May-2017 09-May-2017 12-Sep-2017 12-Sep-2017 12-Sep-2017 15-Sep-2017 15-Sep-2017 15-Sep-2017 22-Jan-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth 5-7 m 50-60 m 2±2 m 27±2 m 44±2 m 64±2 m 143±2 m 286±2 m 2±2 m 31±2 m 57±2 m 71±2 m 145±2 m 305±2 m 26±2 m Volume sampled 127.7 L 116.8 L 129.1 L 130.4 L 115.1 L 119.7 L 114.7 L 116.0 L 124.1 L 128.7 L 119.7 L 124.7 L 118.5 L 126.5 L 128.5 L UNITS pg pg pg pg pg pg pg pg pg pg pg pg pg pg pg pg BDE-7 15 BDE-8 + 11 11 5 5 3 3 4 BDE-15 5 25 38 19 22 22 25 33 19 8 19 12 12 13 22 12 BDE-17 + 25 33 265 491 263 201 356 582 614 282 74 327 98 164 123 321 49 BDE-28 + 33 15 564 1174 626 411 847 1444 1454 672 160 811 220 413 325 775 107 BDE-32 26 30 BDE-35 11 3 5 7 BDE-47 847 19800 57900 15900 10400 20300 40200 29300 15400 5081 27771 4611 10571 7211 23571 2491 BDE-49 37 564 1422 474 339 589 1092 800 447 154 747 143 318 220 638 76 BDE-51 10 127 297 90 62 130 250 191 104 31 157 31 67 50 138 15 BDE-66 54 316 925 255 159 280 563 382 196 90 529 100 201 162 402 45 BDE-71 20 87 225 55 39 83 140 116 71 18 98 14 47 33 74 9 BDE-75 37 34 87 26 16 45 68 51 33 46 14 34 BDE-77 10 99 Date LoQ 14-Feb-2017 14-Feb-2017 9-May-2017 09-May-2017 09-May-2017 09-May-2017 09-May-2017 09-May-2017 12-Sep-2017 12-Sep-2017 12-Sep-2017 15-Sep-2017 15-Sep-2017 15-Sep-2017 22-Jan-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth 5-7 m 50-60 m 2±2 m 27±2 m 44±2 m 64±2 m 143±2 m 286±2 m 2±2 m 31±2 m 57±2 m 71±2 m 145±2 m 305±2 m 26±2 m Volume sampled 127.7 L 116.8 L 129.1 L 130.4 L 115.1 L 119.7 L 114.7 L 116.0 L 124.1 L 128.7 L 119.7 L 124.7 L 118.5 L 126.5 L 128.5 L BDE-79 11 20 41 9 9 33 40 36 15 11 78 24 48 24 80 6 BDE-85 35 202 941 112 75 192 261 133 101 27 222 33 54 41 126 20 BDE-99 714 7099 29889 3809 2639 4829 9039 4779 3739 1202 8532 1172 2312 1542 5172 711 BDE-100 165 1724 7294 1004 723 1294 2444 1474 1014 336 2333 327 630 431 1463 195 BDE-105 61 BDE-116 29 13 33 9 13 BDE-119 + 120 17 23 100 9 10 17 17 12 32 7 12 BDE-126 4 5 15 2 2 3 3 2 3 2 4 2 5 BDE-138 + 166 83 178 47 BDE-140 49 43 BDE-153 57 283 1700 87 42 253 178 79 80 32 178 32 48 30 105 BDE-154 52 288 1691 111 57 210 220 91 100 38 219 39 55 37 131 16 BDE-155 38 15 139 BDE-183 67 128 BDE-203 118 232 36 54 52 BDE-206 904 2592 771 310 BDE-207 1288 4394 1194 440 701 BDE-208 739 236 2337 624 319 359 BDE-209 11509 44020 14920 100 Date LoQ 22-Jan-2018 22-Jan-2018 25-Jan-2018 12-Apr-2018 12-Apr-2018 12-Apr-2018 17-Apr-2018 17-Apr-2018 17-Apr-2018 10-Aug-2018 10-Aug-2018 10-Aug-2018 7-Aug-2018 7-Aug-2018 7-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth 73±2 m 147±2 m 342±2 m 2±2 m 24±2 m 59±2 m 73±2 m 160±2 m 307±2 m 4±2 m 26±2 m 54±2 m 70±2 m 147±2 m 294±2 m Volume sampled 126.8 L 128.2 L 313.7 L 124.7 L 126.7 L 126.5 L 126.9 L 127.3 L 127.3 L 120.9 L 124.5 L 122.7 L 123.5 L 83.0 L 122.8 L UNITS pg pg pg pg pg pg pg pg pg pg pg pg pg pg pg pg BDE-7 15 15 5 6 6 5 6 5 BDE-8 + 11 11 13 5 4 5 3 3 5 7 5 4 BDE-15 5 11 13 30 26 22 24 16 23 34 54 48 47 24 20 27 BDE-17 + 25 33 73 105 205 333 187 239 164 242 323 406 469 437 210 254 372 BDE-28 + 33 15 161 230 457 765 385 614 327 497 680 709 940 904 374 429 733 BDE-32 26 BDE-35 11 5 6 11 BDE-47 847 7191 7841 13771 32502 14002 23002 10202 17102 22402 16067 28367 25867 10167 14967 29967 BDE-49 37 187 222 402 679 316 500 258 374 472 436 612 570 264 375 616 BDE-51 10 39 45 91 121 65 92 47 71 90 96 134 130 63 79 123 BDE-66 54 151 156 293 625 349 472 218 304 464 262 594 426 213 302 665 BDE-71 20 25 32 59 108 52 74 37 55 66 57 92 78 34 70 108 BDE-75 37 21 37 16 31 13 23 29 28 40 42 19 29 39 BDE-77 10 7 4 11 BDE-79 11 28 32 55 188 108 133 76 117 142 BDE-85 35 120 72 125 478 191 233 143 176 262 154 323 311 102 167 394 BDE-99 714 3362 2612 4442 11216 4536 5926 3676 5386 6966 6136 10396 10496 3236 5736 12296 BDE-100 165 799 692 1093 2589 1089 1489 885 1299 1729 1429 2469 2519 843 1419 2949 BDE-105 61 19 21 21 BDE-116 29 13 15 23 10 13 28 19 16 20 11 14 25 101 Date LoQ 22-Jan-2018 22-Jan-2018 25-Jan-2018 12-Apr-2018 12-Apr-2018 12-Apr-2018 17-Apr-2018 17-Apr-2018 17-Apr-2018 10-Aug-2018 10-Aug-2018 10-Aug-2018 7-Aug-2018 7-Aug-2018 7-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth 73±2 m 147±2 m 342±2 m 2±2 m 24±2 m 59±2 m 73±2 m 160±2 m 307±2 m 4±2 m 26±2 m 54±2 m 70±2 m 147±2 m 294±2 m Volume sampled 126.8 L 128.2 L 313.7 L 124.7 L 126.7 L 126.5 L 126.9 L 127.3 L 127.3 L 120.9 L 124.5 L 122.7 L 123.5 L 83.0 L 122.8 L UNITS pg pg pg pg pg pg pg pg pg pg pg pg pg pg pg pg BDE-119 + 120 17 9 7 16 73 28 53 23 24 41 36 68 58 17 40 105 BDE-126 4 1 2 5 5 9 3 2 5 10 8 7 8 4 6 10 BDE-138 + 166 83 54 25 27 29 BDE-140 49 19 BDE-153 57 181 63 135 469 135 180 145 143 223 282 307 361 95 167 305 BDE-154 52 157 82 140 475 150 206 158 170 241 291 334 391 108 192 352 BDE-155 38 28 19 16 23 21 BDE-183 67 BDE-203 118 47 48 BDE-206 904 310 437 BDE-207 1288 473 737 955 427 BDE-208 739 379 414 731 234 BDE-209 11509 4760 6260 9810 4480 3782 6442 102 (b) Date LoQ 09-May-2017 09-May-2017 15-Sep-2017 15-Sep-2017 15-Jan-2018 22-Jan-2018 12-Apr-2018 7-Apr-2018 10-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth 25 m 150 m 25 m 150 m 25 m 150 m 25 m 150 m 25 m 150 m Volume 373.4 L 222.7 L 399.2 L 198.7 L 1104.4 L 747.8 L 944.5 L 824.2 L 473.9 L 644.5 L UNITS pg pg pg pg pg pg pg pg pg pg pg BDE-7 7 6 27 BDE-8 + 11 6 4 19 BDE-10 16 24 121 BDE-12 + 13 10 4 17 BDE-15 7 3 14 BDE-17 + 25 15 5 7 5 BDE-28 + 33 8 6 5 9 12 10 9 BDE-37 64 26 30 BDE-47 129 129 110 153 136 302 131 181 138 BDE-49 43 16 13 BDE-85 8 5 4 3 14 3 3 7 BDE-99 127 177 138 152 133 315 86 91 112 BDE-100 27 10 32 27 33 27 68 26 24 31 BDE-119 + 120 9 6 BDE-126 6 2 BDE-138 + 166 22 9 BDE-140 15 5 BDE-153 17 13 12 8 17 15 32 17 10 14 BDE-154 13 8 10 10 17 15 27 17 7 15 BDE-155 10 5 BDE-183 49 29 18 15 BDE-203 173 60 103 Date LoQ 09-May-2017 09-May-2017 15-Sep-2017 15-Sep-2017 15-Jan-2018 22-Jan-2018 12-Apr-2018 7-Apr-2018 10-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth 25 m 150 m 25 m 150 m 25 m 150 m 25 m 150 m 25 m 150 m Volume 373.4 L 222.7 L 399.2 L 198.7 L 1104.4 L 747.8 L 944.5 L 824.2 L 473.9 L 644.5 L UNITS pg pg pg pg pg pg pg pg pg pg pg BDE-206 249 109 385 121 87 BDE-207 270 133 139 179 113 670 310 131 190 BDE-208 295 117 529 127 102 142 BDE-209 1539 501 1182 1585 1543 5878 2307 885 1328 BDE-209* 1539 1268 104 Table 3.6: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PBDE congeners concentrations (pg/L) in SoG seawater at Station S4-1.5. Quantifiable congeners are in bold. Detectable congeners, below LoQ but above LoD, are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). BDE-209* has been corrected for the procedural blank (Table 3.2c). (a) Date 14-Feb-2017 14-Feb-2017 09-May-17 09-May-2017 09-May-2017 09-May-2017 09-May-2017 09-May-2017 12-Sep-2017 12-Sep-2017 12-Sep-2017 15-Sep-2017 15-Sep-2017 15-Sep-2017 22-Jan-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth 5-7 m 50-60 m 2±2 m 27±2 m 44±2 m 64±2 m 143±2 m 286±2 m 2±2 m 31±2 m 57±2 m 71±2 m 145±2 m 305±2 m 26±2 m Volume sampled 127.7 L 116.8 L 129.1 L 130.4 L 115.1 L 119.7 L 114.7 L 116.0 L 124.1 L 128.7 L 119.7 L 124.7 L 118.5 L 126.5 L 128.5 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L BDE-7 BDE-8 + 11 0.04 0.05 0.03 0.03 0.03 BDE-15 0.20 0.32 0.15 0.17 0.19 0.21 0.28 0.17 0.07 0.15 0.10 0.10 0.11 0.17 0.09 BDE-17 + 25 2.1 4.2 2.0 1.5 3.1 4.9 5.4 2.4 0.59 2.5 0.82 1.3 1.0 2.5 0.38 BDE-28 + 33 4.4 10.0 4.8 3.1 7.3 12.1 12.7 5.8 1.3 6.3 1.8 3.3 2.7 6.1 0.83 BDE-32 0.23 BDE-35 0.03 0.04 0.06 BDE-47 155 496 123 80 176 336 255 133 40.9 216 38.5 85 61 186 19.4 BDE-49 4.4 12.2 3.7 2.6 5.1 9.1 7.0 3.9 1.2 5.8 1.2 2.6 1.9 5.0 0.59 BDE-51 1.0 2.5 0.70 0.47 1.1 2.1 1.7 0.90 0.25 1.2 0.26 0.53 0.42 1.1 0.12 BDE-66 2.5 7.9 2.0 1.2 2.4 4.7 3.3 1.7 0.72 4.1 0.83 1.6 1.4 3.2 0.35 BDE-71 0.68 1.9 0.43 0.30 0.72 1.2 1.0 0.61 0.15 0.76 0.12 0.38 0.27 0.58 0.07 BDE-75 0.26 0.74 0.20 0.12 0.39 0.57 0.44 0.28 0.35 0.11 0.27 BDE-77 BDE-79 0.15 0.35 0.07 0.07 0.28 0.34 0.31 0.13 0.09 0.60 0.20 0.38 0.21 0.63 0.04 BDE-85 1.6 8.1 0.87 0.57 1.7 2.2 1.2 0.87 0.22 1.7 0.27 0.43 0.34 0.99 0.15 BDE-99 55.6 256 29.5 20.2 41.9 75.5 41.7 32.2 9.7 66.3 9.8 18.5 13.0 40.9 5.5 105 Date 14-Feb-2017 14-Feb-2017 09-May-17 09-May-2017 09-May-2017 09-May-2017 09-May-2017 09-May-2017 12-Sep-2017 12-Sep-2017 12-Sep-2017 15-Sep-2017 15-Sep-2017 15-Sep-2017 22-Jan-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth 5-7 m 50-60 m 2±2 m 27±2 m 44±2 m 64±2 m 143±2 m 286±2 m 2±2 m 31±2 m 57±2 m 71±2 m 145±2 m 305±2 m 26±2 m Volume sampled 127.7 L 116.8 L 129.1 L 130.4 L 115.1 L 119.7 L 114.7 L 116.0 L 124.1 L 128.7 L 119.7 L 124.7 L 118.5 L 126.5 L 128.5 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L BDE-100 13.5 62 7.8 5.5 11.2 20.4 12.8 8.7 2.7 18.1 2.7 5.1 3.6 11.6 1.5 BDE-105 BDE-116 0.10 0.29 0.08 0.10 BDE-119 + 120 0.18 0.86 0.07 0.09 0.14 0.15 0.10 0.25 0.06 0.09 BDE-126 0.04 0.13 0.02 0.01 0.03 0.03 0.01 0.02 0.01 0.03 0.02 0.04 BDE-138 + 166 1.5 0.41 BDE-140 0.37 BDE-153 2.2 14.6 0.67 0.32 2.2 1.5 0.69 0.69 0.25 1.4 0.26 0.38 0.25 0.83 BDE-154 2.3 14.5 0.86 0.44 1.8 1.8 0.80 0.86 0.31 1.7 0.32 0.44 0.31 1.0 0.12 BDE-155 0.12 1.2 BDE-183 1.1 BDE-203 2.0 0.31 0.42 0.41 BDE-206 22.2 6.7 2.5 BDE-207 37.6 10.4 3.4 5.5 BDE-208 1.8 20.0 5.4 2.5 2.8 BDE-209 377 130 106 Date 22-Jan-2018 22-Jan-2018 25-Jan-2018 12-Apr-2018 12-Apr-2018 12-Apr-2018 17-Apr-2018 17-Apr-2018 17-Apr-2018 10-Aug-2018 10-Aug-2018 10-Aug-2018 7-Aug-2018 7-Aug-2018 7-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth 73±2 m 147±2 m 342±2 m 2±2 m 24±2 m 59±2 m 73±2 m 160±2 m 307±2 m 4±2 m 26±2 m 54±2 m 70±2 m 147±2 m 294±2 m Volume sampled 126.8 L 128.2 L 313.7 L 124.7 L 126.7 L 126.5 L 126.9 L 127.3 L 127.3 L 120.9 L 124.5 L 122.7 L 123.5 L 83.0 L 122.8 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L BDE-7 0.05 0.04 0.04 0.05 0.04 0.05 0.04 BDE-8 + 11 0.04 0.04 0.03 0.04 0.03 0.03 0.04 0.06 0.04 0.03 BDE-15 0.08 0.10 0.10 0.21 0.18 0.19 0.13 0.18 0.27 0.44 0.39 0.38 0.20 0.24 0.22 BDE-17 + 25 0.58 0.82 0.65 2.7 1.5 1.9 1.3 1.9 2.5 3.4 3.8 3.6 1.7 3.1 3.0 BDE-28 + 33 1.3 1.8 1.5 6.1 3.0 4.9 2.6 3.9 5.3 5.9 7.5 7.4 3.0 5.2 6.0 BDE-32 BDE-35 0.04 0.04 0.09 BDE-47 57 61 43.9 261 111 182 80 134 176 133 228 211 82 180 244 BDE-49 1.5 1.7 1.3 5.4 2.5 4.0 2.0 2.9 3.7 3.6 4.9 4.6 2.1 4.5 5.0 BDE-51 0.31 0.35 0.29 0.97 0.51 0.72 0.37 0.55 0.71 0.79 1.1 1.1 0.51 0.95 1.0 BDE-66 1.2 1.2 0.93 5.0 2.8 3.7 1.7 2.4 3.6 2.2 4.8 3.5 1.7 3.6 5.4 BDE-71 0.20 0.25 0.19 0.87 0.41 0.59 0.29 0.43 0.52 0.47 0.74 0.63 0.27 0.84 0.88 BDE-75 0.07 0.29 0.13 0.24 0.10 0.18 0.23 0.23 0.32 0.34 0.16 0.35 0.32 BDE-77 0.06 0.03 0.13 BDE-79 0.22 0.25 0.17 1.5 0.85 1.1 0.59 0.92 1.1 BDE-85 0.94 0.56 0.40 3.8 1.5 1.8 1.1 1.4 2.1 1.3 2.6 2.5 0.83 2.0 3.2 BDE-99 26.5 20.4 14.2 90 35.8 46.8 29.0 42.3 55 51 84 86 26.2 69 100 BDE-100 6.3 5.4 3.5 20.8 8.6 11.8 7.0 10.2 13.6 11.8 19.8 20.5 6.8 17.1 24.0 BDE-105 0.15 0.16 0.17 BDE-116 0.04 0.12 0.18 0.08 0.10 0.22 0.16 0.13 0.16 0.09 0.17 0.20 BDE-119 + 120 0.07 0.05 0.05 0.58 0.22 0.42 0.18 0.19 0.32 0.30 0.55 0.47 0.14 0.48 0.86 BDE-126 0.01 0.02 0.02 0.04 0.07 0.03 0.01 0.04 0.08 0.06 0.05 0.06 0.03 0.07 0.08 107 Date 22-Jan-2018 22-Jan-2018 25-Jan-2018 12-Apr-2018 12-Apr-2018 12-Apr-2018 17-Apr-2018 17-Apr-2018 17-Apr-2018 10-Aug-2018 10-Aug-2018 10-Aug-2018 7-Aug-2018 7-Aug-2018 7-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth 73±2 m 147±2 m 342±2 m 2±2 m 24±2 m 59±2 m 73±2 m 160±2 m 307±2 m 4±2 m 26±2 m 54±2 m 70±2 m 147±2 m 294±2 m Volume sampled 126.8 L 128.2 L 313.7 L 124.7 L 126.7 L 126.5 L 126.9 L 127.3 L 127.3 L 120.9 L 124.5 L 122.7 L 123.5 L 83.0 L 122.8 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L BDE-138 + 166 0.43 0.20 0.22 0.24 BDE-140 0.15 BDE-153 1.4 0.49 0.43 3.8 1.1 1.4 1.1 1.1 1.7 2.3 2.5 2.9 0.77 2.0 2.5 BDE-154 1.2 0.64 0.45 3.8 1.2 1.6 1.2 1.3 1.9 2.4 2.7 3.2 0.87 2.3 2.9 BDE-155 0.23 0.15 0.13 0.18 0.17 BDE-183 BDE-203 0.15 0.37 BDE-206 2.4 1.4 BDE-207 3.7 5.7 3.0 3.4 BDE-208 3.0 3.2 2.3 1.8 BDE-209 37.5 48.8 31.3 35.3 31.3 52.5 108 (b) Date 09-May-2017 09-May-2017 15-Sep-2017 15-Sep-2017 15-Jan-2018 22-Jan-2018 12-Apr-2018 7-Apr-2018 10-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth 25 m 150 m 25 m 150 m 25 m 150 m 25 m 150 m 25 m 150 m Volume 373.4 L 222.7 L 399.2 L 198.7 L 1104.4 L 747.8 L 944.5 L 824.2 L 473.9 L 644.5 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L BDE-7 0.01 0.04 BDE-8 + 11 0.01 0.03 BDE-10 0.05 0.19 BDE-12 + 13 0.01 0.03 BDE-15 0.01 0.02 BDE-17 + 25 0.01 0.01 0.01 BDE-28 + 33 0.01 0.01 0.01 0.02 0.02 0.01 BDE-37 0.05 0.05 BDE-47 0.32 0.55 0.14 0.18 0.32 0.16 0.38 0.21 BDE-49 0.02 0.02 BDE-85 0.01 0.02 0.002 0.01 0.003 0.01 0.01 BDE-99 0.44 0.69 0.14 0.18 0.33 0.10 0.19 0.17 BDE-100 0.03 0.08 0.13 0.03 0.04 0.07 0.03 0.05 0.05 BDE-119 + 120 0.01 BDE-126 0.00 BDE-138 + 166 0.01 BDE-140 0.01 BDE-153 0.04 0.03 0.04 0.02 0.02 0.03 0.02 0.02 0.02 BDE-154 0.02 0.03 0.05 0.02 0.02 0.03 0.02 0.01 0.02 BDE-155 0.01 BDE-183 0.08 0.02 0.02 BDE-203 0.06 109 Date 09-May-2017 09-May-2017 15-Sep-2017 15-Sep-2017 15-Jan-2018 22-Jan-2018 12-Apr-2018 7-Apr-2018 10-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth 25 m 150 m 25 m 150 m 25 m 150 m 25 m 150 m 25 m 150 m Volume 373.4 L 222.7 L 399.2 L 198.7 L 1104.4 L 747.8 L 944.5 L 824.2 L 473.9 L 644.5 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L BDE-206 0.10 0.41 0.15 0.13 BDE-207 0.36 0.70 0.16 0.15 0.71 0.38 0.28 0.29 BDE-208 0.11 0.56 0.15 0.21 0.22 BDE-209 2.2 5.9 1.4 2.1 6.2 2.8 1.9 2.1 BDE-209* 1.3 110 Table 3.7: Detectable (> LoD) and quantifiable (>LoQ) dissolved PBDE congeners in the Salish Sea at Stations NG, HS, and JF2 (a) and particulate PBDE congeners at Station NG (b). Quantifiable congeners are in bold. Detectable congeners, below LoQ but above LoD, are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). Particulate BDE-209* has been corrected for the procedural blank (Table 3.2c). (a) Date LoQ 25-Aug-2018 25-Aug-2018 25-Aug-2018 24-Aug-2018 24-Aug-2018 24-Aug-2018 24-Aug-2018 18-Jun-2017 18-Jun-2017 27-Sep-2018 27-Sep-2018 20-Sep-2018 Station # NG NG NG NG NG NG HS JF2 JF2 JF2 JF2 P26 Depth 0 m 25 m 50 m 75 m 150 m 330 m Integr. water col. 20 m 160 m 20 m 160 m 25 m Vol. sampled 157.0 L 117.2 L 115.5 L 119.1 L 114.1 L 149.2 L 453.4 L 106.9 L 116.0 L 461.1 L 459.3 L 462.3 L UNITS pg pg pg pg pg pg pg pg pg pg pg pg pg BDE-7 15 8 6 BDE-8 + 11 11 7 4 4 BDE-15 5 12 8 7 6 4 8 28 2 2 5 8 6 BDE-17 + 25 33 66 44 36 26 26 49 118 32 30 15 BDE-28 + 33 15 101 77 88 61 55 110 306 20 30 73 86 59 BDE-47 847 1202 711 647 456 528 1112 2782 450 620 803 912 887 BDE-49 37 42 25 25 15 16 35 85 13 24 26 32 26 BDE-51 10 7 4 5 3 7 19 3 4 BDE-66 54 27 19 66 31 26 24 BDE-71 20 11 BDE-79 11 6 5 3 6 8 26 8 6 8 BDE-99 714 259 227 217 246 BDE-100 165 52 97 53 57 51 57 BDE-203 118 168 BDE-206 904 693 BDE-207 1288 1882 BDE-208 739 1276 BDE-209 11509 21100 111 (b) Date LoQ 24-Aug-2018 24-Aug-2018 Station # NG NG Depth 25 m 150 m Volume 1436.6 L 1026.5 L UNITS pg pg pg BDE-7 15 7 9 BDE-8 + 11 11 4 6 BDE-10 17 7 32 BDE-12 + 13 22 4 5 BDE-15 11 3 4 BDE-17 + 25 18 5 7 BDE-28 + 33 14 10 12 BDE-47 309 195 591 BDE-49 55 27 BDE-51 31 5 BDE-66 56 13 BDE-85 18 6 23 BDE-99 307 137 623 BDE-100 66 35 152 BDE-116 47 11 BDE-153 40 10 43 BDE-154 31 10 45 BDE-155 15 6 BDE-183 56 20 BDE-203 211 59 BDE-206 612 81 275 BDE-207 616 256 344 BDE-208 760 174 349 BDE-209 3770 775 4758 BDE-209* 3770 148 112 Table 3.8: Detectable (> LoD) and quantifiable (>LoQ) dissolved PBDE congeners in the Salish Sea at Stations NG, HS, and JF2 (a) and particulate PBDE congeners at Station NG (b). Quantifiable congeners are in bold. Detectable congeners, below LoQ but above LoD, are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). BDE-209* has been corrected for the procedural blank (Table 3.2c). (a) Date 25-Aug-2018 25-Aug-2018 25-Aug-2018 24-Aug-2018 24-Aug-2018 24-Aug-2018 24-Aug-2018 18-Jun-2017 18-Jun-2017 27-Sep-2018 27-Sep-2018 20-Sep-2018 Station # NG NG NG NG NG NG HS JF2 JF2 JF2 JF2 P26 Depth 0 m 25 m 50 m 75 m 150 m 330 m Integr. water col. 20 m 160 m 20 m 160 m 25 m Vol. sampled 157.0 L 117.2 L 115.5 L 119.1 L 114.1 L 149.2 L 453.4 L 106.9 L 116.0 L 461.1 L 459.3 L 462.3 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L BDE-7 0.02 0.01 BDE-8 + 11 0.02 0.01 0.01 BDE-15 0.08 0.07 0.06 0.05 0.03 0.05 0.06 0.02 0.02 0.01 0.02 0.01 BDE-17 + 25 0.42 0.37 0.31 0.21 0.23 0.33 0.26 0.07 0.06 0.03 BDE-28 + 33 0.64 0.66 0.77 0.51 0.48 0.74 0.67 0.19 0.26 0.16 0.19 0.13 BDE-47 7.7 6.1 5.6 3.8 4.6 7.4 6.1 4.2 5.3 1.7 2.0 1.9 BDE-49 0.27 0.21 0.22 0.13 0.14 0.23 0.19 0.12 0.21 0.06 0.07 0.06 BDE-51 0.05 0.04 0.04 0.03 0.04 0.04 0.03 0.01 BDE-66 0.17 0.13 0.15 0.07 0.06 0.05 BDE-71 0.03 BDE-79 0.04 0.05 0.03 0.06 0.05 0.06 0.02 0.01 0.02 BDE-99 0.57 1.95 0.47 0.53 BDE-100 0.33 0.21 0.50 0.49 0.11 0.12 BDE-203 0.36 BDE-206 1.5 BDE-207 4.1 BDE-208 2.8 BDE-209 45.6 113 (b) Date 24-Aug-2018 24-Aug-2018 Station # NG NG Depth 25 m 150 m Volume 1436.6 L 1026.5 L UNITS pg/L pg/L BDE-7 0.005 0.008 BDE-8 + 11 0.003 0.006 BDE-10 0.005 0.031 BDE-12 + 13 0.003 0.005 BDE-15 0.002 0.004 BDE-17 + 25 0.004 0.007 BDE-28 + 33 0.007 0.011 BDE-47 0.14 0.58 BDE-49 0.027 BDE-51 0.005 BDE-66 0.013 BDE-85 0.004 0.023 BDE-99 0.096 0.61 BDE-100 0.024 0.15 BDE-116 0.011 BDE-153 0.007 0.042 BDE-154 0.007 0.044 BDE-155 0.005 BDE-183 0.020 BDE-203 0.058 BDE-206 0.057 0.27 BDE-207 0.18 0.33 BDE-208 0.12 0.34 BDE-209 0.54 4.6 BDE-209* 0.1 114 Table 3.9: Dissolved congener concentration ratios at Station S4-1.5 (Table 3.6a), as well as HS, NG, and JF2 (Table 3.8a). The calculation is based on the average dissolved PBDE concentrations at each station. Station S4-1.5 HS NG JF2 BDE-28+33/BDE-100 0.39 3.2 12 3.1 BDE-47/BDE-100 12 29 107 34 BDE-28+33/BDE-47 0.03 0.11 0.11 0.09 BDE-17+25/BDE-100 0.18 1.22 5.7 1.2 115 Table 3.10: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PBDE congeners in the Iona effluent plume (S1), Burrard Inlet (S3, S3b), and in the Fraser River (FR). Quantifiable congeners are in bold. Detectable congeners, below LoQ but above LoD, are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). Particulate BDE-209* has been corrected for the procedural blank (Table 3.2c). (a) Date LoQ 11-Dec-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 23-Jun-2017 13-Feb-2018 Station # Stn 1 Stn 3 Stn 3b Stn 3b FR FR Depth 53-60 m 5-25 m 15-35 m 15-24 m 5 m 3 m Volume sampled 110.1 L 207.6 L 117.0 L 101.5 L 109.8 L 368.8 L UNITS pg pg pg pg pg pg pg BDE-7 15 7 29 18 18 BDE-8 + 11 11 19 8 8 4 BDE-12 + 13 8 5 BDE-15 5 37 50 14 18 9 26 BDE-17 + 25 33 489 382 143 121 31 54 BDE-28 + 33 15 970 856 217 198 73 103 BDE-35 11 6 6 BDE-47 847 22815 21701 4800 3411 910 2721 BDE-49 37 586 669 158 128 34 100 BDE-51 10 138 114 27 23 9 10 BDE-66 54 309 404 90 70 17 50 BDE-71 20 70 76 11 14 14 BDE-75 37 28 38 BDE-77 10 5 BDE-79 11 17 27 9 5 BDE-85 35 123 246 63 34 14 40 BDE-99 714 3873 7584 1752 1162 302 1162 BDE-100 165 1155 2231 413 302 83 258 116 Date LoQ 11-Dec-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 23-Jun-2017 13-Feb-2018 Station # Stn 1 Stn 3 Stn 3b Stn 3b FR FR Depth 53-60 m 5-25 m 15-35 m 15-24 m 5 m 3 m Volume sampled 110.1 L 207.6 L 117.0 L 101.5 L 109.8 L 368.8 L UNITS pg pg pg pg pg pg pg BDE-116 29 12 10 BDE-119 + 120 17 28 7 6 BDE-126 4 4 2 4 BDE-128 110 42 BDE-138 + 166 83 45 28 BDE-153 57 81 402 179 42 43 BDE-154 52 99 406 96 49 46 BDE-155 38 40 BDE-183 67 26 167 588 BDE-203 118 464 50 BDE-206 904 2656 BDE-207 1288 4395 BDE-208 739 2743 BDE-209 11509 5490 33440 117 (b) Date LoQ 05-Oct-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 23-Jun-2017 13-Feb-2018 Station # Stn 1 Stn 3 Stn 3b Stn 3b FR FR Depth 65 m 5-25 m 20-30 m 18-20 m 5 m 3 m Volume 745 L 187.6 L 172 L 191.9 L 109.8 L 368.8 L UNITS pg pg pg pg pg pg BDE-7 15 5 4 3 BDE-8 + 11 11 6 5 7 2 2 BDE-15 11 7 6 8 BDE-17 + 25 18 70 26 32 16 73 BDE-28 + 33 14 97 11 52 6 179 6 BDE-47 309 6882 340 3923 185 3977 370 BDE-49 55 210 43 127 35 129 BDE-51 31 21 14 23 BDE-66 56 158 12 94 95 9 BDE-71 50 16 21 11 BDE-75 34 8 9 BDE-79 29 6 BDE-85 18 442 18 174 4 75 18 BDE-99 307 8994 424 4560 133 1646 476 BDE-100 66 1741 93 965 33 482 95 BDE-105 30 16 5 BDE-116 47 19 7 BDE-119 + 120 25 15 12 7 BDE-126 14 3 4 BDE-128 72 24 54 BDE-138 + 166 28 146 11 52 17 BDE-140 20 26 7 13 5 BDE-153 40 819 60 468 13 108 53 118 Date LoQ 05-Oct-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 23-Jun-2017 13-Feb-2018 Station # Stn 1 Stn 3 Stn 3b Stn 3b FR FR Depth 65 m 5-25 m 20-30 m 18-20 m 5 m 3 m Volume 745 L 187.6 L 172 L 191.9 L 109.8 L 368.8 L UNITS pg pg pg pg pg pg BDE-154 31 707 52 446 16 105 38 BDE-155 15 40 11 34 6 BDE-183 56 258 25 60 26 BDE-203 211 785 61 67 BDE-206 612 8424 310 383 373 146 BDE-207 616 7377 455 721 84 711 228 BDE-208 760 5220 286 383 384 127 BDE-209 3770 98810 4386 9687 994 3946 3424 BDE-209* 3770 94200 5077 119 Table 3.11: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PBDE congeners concentrations (pg/L) in the Iona effluent plume (S1), Burrard Inlet (S3, S3b) and in the Fraser River (FR). Quantifiable congeners are in bold. Detectable congeners, below LoQ but above LoD, are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = estimated maximum (MAX). BDE-209* has been corrected for the procedural blank (Table 3.11c). (a) Date 11-Dec-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 23-Jun-2017 13-Feb-2018 Station # Stn 1 Stn 3 Stn 3b Stn 3b FR FR Depth 53-60 m 5-25 m 15-35 m 15-24 m 5 m 3 m Volume sampled 110.1 L 207.6 L 117.0 L 101.5 L 109.8 L 368.8 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L BDE-7 0.06 0.14 0.16 0.18 BDE-8 + 11 0.09 0.07 0.08 0.01 BDE-12 + 13 0.01 BDE-15 0.33 0.24 0.12 0.18 0.08 0.07 BDE-17 + 25 4.4 1.8 1.2 1.2 0.28 0.15 BDE-28 + 33 8.8 4.1 1.9 1.9 0.66 0.28 BDE-35 0.03 0.02 BDE-47 207 105 41.0 33.6 8.3 7.4 BDE-49 5.3 3.2 1.3 1.3 0.31 0.27 BDE-51 1.3 0.55 0.23 0.23 0.08 0.03 BDE-66 2.8 1.9 0.77 0.69 0.15 0.14 BDE-71 0.63 0.36 0.10 0.14 0.04 BDE-75 0.25 0.18 BDE-77 0.01 BDE-79 0.15 0.13 0.09 0.01 BDE-85 1.1 1.2 0.54 0.33 0.13 0.11 BDE-99 35.2 36.5 15.0 11.4 2.7 3.2 BDE-100 10.5 10.7 3.5 3.0 0.76 0.70 120 Date 11-Dec-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 23-Jun-2017 13-Feb-2018 Station # Stn 1 Stn 3 Stn 3b Stn 3b FR FR Depth 53-60 m 5-25 m 15-35 m 15-24 m 5 m 3 m Volume sampled 110.1 L 207.6 L 117.0 L 101.5 L 109.8 L 368.8 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L BDE-116 0.06 0.03 BDE-119 + 120 0.13 0.06 0.02 BDE-126 0.02 0.02 0.01 BDE-128 0.20 BDE-138 + 166 0.22 0.24 BDE-153 0.74 1.9 1.5 0.42 0.12 BDE-154 0.90 2.0 0.82 0.48 0.12 BDE-155 0.19 BDE-183 0.23 0.81 5.0 BDE-203 2.2 0.43 BDE-206 12.8 BDE-207 21.2 BDE-208 13.2 BDE-209 49.9 161 121 (b) Date 05-Oct-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 23-Jun-2017 13-Feb-2018 Station # Stn 1 Stn 3 Stn 3b Stn 3b FR FR Depth 65 m 5-25 m 20-30 m 18-20 m 5 m 3 m Volume 745 L 187.6 L 172 L 191.9 L 109.8 L 368.8 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L BDE-7 0.01 0.02 0.02 BDE-8 + 11 0.01 0.03 0.04 0.01 0.02 BDE-15 0.01 0.03 0.08 BDE-17 + 25 0.09 0.14 0.18 0.08 0.66 BDE-28 + 33 0.13 0.06 0.30 0.03 1.6 0.02 BDE-47 9.2 1.8 22.8 0.97 36.2 1.0 BDE-49 0.28 0.23 0.74 0.18 1.2 BDE-51 0.03 0.08 0.21 BDE-66 0.21 0.07 0.54 0.86 0.02 BDE-71 0.02 0.12 0.10 BDE-75 0.01 0.08 BDE-79 0.01 BDE-85 0.59 0.09 1.0 0.02 0.68 0.05 BDE-99 12.1 2.3 26.5 0.69 15.0 1.3 BDE-100 2.3 0.50 5.6 0.17 4.4 0.26 BDE-105 0.02 0.03 BDE-116 0.03 0.04 BDE-119 + 120 0.02 0.07 0.06 BDE-126 0.005 0.02 BDE-128 0.03 0.29 BDE-138 + 166 0.20 0.06 0.30 0.15 BDE-140 0.04 0.04 0.07 0.04 BDE-153 1.10 0.32 2.7 0.07 0.98 0.14 122 Date 05-Oct-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 23-Jun-2017 13-Feb-2018 Station # Stn 1 Stn 3 Stn 3b Stn 3b FR FR Depth 65 m 5-25 m 20-30 m 18-20 m 5 m 3 m Volume 745 L 187.6 L 172 L 191.9 L 109.8 L 368.8 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L BDE-154 0.95 0.27 2.6 0.08 0.96 0.10 BDE-155 0.05 0.06 0.20 0.05 BDE-183 0.35 0.13 0.35 0.24 BDE-203 1.05 0.35 0.61 BDE-206 11.3 1.7 2.2 3.4 0.40 BDE-207 9.9 2.4 4.2 0.44 6.5 0.62 BDE-208 7.0 1.5 2.2 3.5 0.34 BDE-209 133 23.4 56.3 5.2 35.9 9.3 BDE-209* 126 29.5 123 Table 3.12: Particulate-to-total PBDE ratios for concentrations above LoQ in samples collected in the Salish Sea (S2, S3, S3b, S4-1.5, NG and FR). Numbers in italics are above LoD but below LoQ. Bold numbers indicate values above LoQ. Empty cells indicate that blank-corrected values were below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<). Values in the yellow background are considered as good quality. Station # Location Date Depth (m) Type BDE-17+25 BDE-28+33 BDE-47 BDE-49 BDE-99 BDE-100 BDE-153 BDE-154 BDE-209 Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) S1 Iona plume 11-Dec-2013 50-60 Dissolved 4.4 8.8 207 5.3 35.2 10.5 0.74 0.90 49.9 5-Oct-2013 65 Particulate 0.09 0.13 9.2 0.28 12.1 2.3 1.10 0.95 126 - - part/total (%) 2.1 1.5 4.3 5.0 26 18 60 51 72 S2 Bowen Island 11-Dec-2013 45-55 Dissolved 4.5 8.4 189 6.0 38 11.2 0.7 1.0 37 55 Particulate 0.007 69 - part/total (%) 0.7 65.1 S2 Bowen Island 1-Oct-2014 50 Dissolved 2.8 5.2 123 5.1 70 17.8 6.9 4.9 93 48-52 Particulate 0.004 0.21 0.18 0.06 0.03 0.03 - part/total (%) 0.1 0.17 0.26 0.31 0.4 0.6 S2 Bowen Island 16-Dec-2015 55-65 Dissolved 1.4 3.0 121 2.9 91 21.6 7.6 6.8 106 55 Particulate - part/total (%) S3 Burrard Inlet (Inner Harbor) 5-Dec-2014 5-25 Dissolved 1.84 4.12 105 3.2 37 10.7 1.9 2.0 161 5-25 Particulate 0.14 0.06 1.8 0.23 2.3 0.50 0.32 0.27 - part/total (%) 7.1 1.4 1.7 7 5.8 4.4 14 12 S3b Burrard Inlet (Central Harbor) 17-Dec-2015 15-35 Dissolved 1.2 1.9 41 1.3 15 3.5 1.5 0.8 20-30 Particulate 0.18 0.30 22.8 0.74 26.5 5.61 2.72 2.59 30 - part/total (%) 13 14 36 35 64 61 64 76 S3b Burrard Inlet (Central Harbor) 31-Aug-2016 15-24 Dissolved 1.2 1.9 34 1.3 11 3.0 0.42 0.5 18-20 Particulate 0.08 0.03 1.0 0.18 0.7 0.17 0.07 0.08 - part/total (%) 6.5 1.6 2.8 13 5.7 5.5 13.8 15.1 124 Station # Location Date Depth (m) Type BDE-17+25 BDE-28+33 BDE-47 BDE-49 BDE-99 BDE-100 BDE-153 BDE-154 BDE-209 Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) S4-1.5 Central SoG 9-May-2017 27±2 Dissolved 1.5 3.1 80 2.6 20 5.5 0.3 0.4 25 Particulate 0.03 0.04 0.02 - part/total (%) 0.5 10.0 4.5 S4-1.5 Central SoG 9-May-2017 143±2 Dissolved 5.4 12.7 256 7.0 42 12.9 0.7 0.8 130 150 Particulate - part/total (%) S4-1.5 Central SoG 12-Sep-2017 31±2 Dissolved 2.5 6.3 216 5.8 66 18.1 1.4 1.7 15-Sep-2017 25 Particulate 0.31 0.4 0.08 0.03 0.03 - - part/total (%) 0.1 0.6 0.4 2.1 1.5 S4-1.5 Central SoG 15-Sep-2017 145±2 Dissolved 1.0 2.7 61 1.9 13 3.6 0.25 0.31 150 Particulate 0.55 0.7 0.13 0.04 0.05 - part/total (%) 0.9 4.9 3.6 13.7 14.1 S4-1.5 Central SoG 22-Jan-2018 26±2 Dissolved 0.4 0.8 19 0.6 6 1.5 0.12 15-Jan-2018 25 Particulate 0.01 0.14 0.14 0.030 0.02 0.016 - - part/total (%) 0.6 0.7 2.4 1.9 11.3 S4-1.5 Central SoG 22-Jan-2018 147±2 Dissolved 0.8 1.8 61 1.7 20 5.4 0.5 0.6 49 150 Particulate 0.01 0.18 0.18 0.04 0.02 0.020 - part/total (%) 0.4 0.29 0.87 0.7 3.9 3.0 S4-1.5 Central SoG 12-Apr-2018 24±2 Dissolved 1.5 3.0 111 2.5 36 8.6 1.1 1.2 25 Particulate 0.005 0.010 0.32 0.017 0.33 0.07 0.034 0.029 1.3 - part/total (%) 0.4 0.32 0.29 0.7 0.9 0.8 3.1 2.4 S4-1.5 Central SoG 7-Apr-2018 160±2 Dissolved 1.9 3.9 134 2.9 42 10.2 1.1 1.3 150 Particulate 0.009 0.015 0.16 0.10 0.03 0.021 0.021 - part/total (%) 0.4 0.38 0.1 0.2 0.3 1.8 1.5 S4-1.5 Central SoG 10-Aug-2018 26±2 Dissolved 3.8 7.5 228 4.9 84 19.8 2.5 2.7 25 Particulate 0.020 0.4 0.19 0.05 0.021 0.015 - part/total (%) 0.26 0.17 0.2 0.3 0.8 0.6 125 Station # Location Date Depth (m) Type BDE-17+25 BDE-28+33 BDE-47 BDE-49 BDE-99 BDE-100 BDE-153 BDE-154 BDE-209 Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) Conc. (pg/L) S4-1.5 Central SoG 7-Aug-2018 147±2 Dissolved 3.1 5.2 180 4.5 69 17 2.0 2.3 150 Particulate 0.008 0.014 0.21 0.02 0.17 0.05 0.021 0.023 - part/total (%) 0.3 0.27 0.12 0.4 0.25 0.3 1.0 1.0 NG Norther SoG 25-Aug-2018 25 Dissolved 0.4 0.7 6 0.21 25 Particulate 0.004 0.007 0.14 0.10 0.024 0.007 0.007 - part/total (%) 1.0 1.1 2.2 NG Norther SoG 24-Aug-2018 150 Dissolved 0.23 0.5 5 0.14 150 Particulate 0.007 0.011 0.58 0.027 0.61 0.15 0.042 0.044 0.1 - part/total (%) 2.8 2.3 11.1 16.0 FR Fraser River 23-Jun-2017 5 Dissolved 0.28 0.7 8 0.31 3 0.8 5 Particulate 0.66 1.63 36.2 1.2 15.0 4.4 0.98 0.96 - part/total (%) 70.1 71 81 79.3 84.5 85.3 FR Fraser River 13-Feb-2018 3 Dissolved 0.15 0.28 7 0.27 3.2 0.7 0.12 0.12 3 Particulate 0.02 1.0 1.3 0.26 0.14 0.10 - part/total (%) 5.5 12 29 27 54.8 45.0 126 Table 3.13: Sum of all quantifiable (> LoQ) and detectable (> LoD) particulate and dissolved PBDE concentrations measured at different locations in the Salish Sea. S1 S2 S4-1.5 S3 S3b NG HS JF2 Total particulate PBDE concentration (pg/L) Quantifiable 189 0 – 97 2 ± 3 29 0 – 124 6 - - Detectable 190 1 – 97 4 ± 3 35 8 – 130 7 - - Total dissolved PBDE concentration (pg/L) Quantifiable 279 309 ± 56 256 ± 243 381 54 – 73 3 ± 4 8 1 ± 1 Detectable 330 354 ± 45 266 ± 241 382 55 – 74 7 ± 2 8 5 ± 3 Table 3.14: Total quantifiable and detectable dissolved PBDE concentrations in the Fraser River (Table 3.11a) and in surface water at Station S4-1.5 (Table 3.6a). Fraser River S4-1.5 Dissolved June 2017 Feb 2018 May 2017 Sep 2017 Apr 2018 Aug 2018 Total quantifiable conc. (pg/L) 9 12 169 58 406 219 Total detectable conc. (pg/L) 13 13 169 59 408 251 Table 3.15: Input setting used in the Box Model simulation. Congener Vancouver WWTP load (Iona, 1997~1998, 2002~2005, g/d) Victoria WWTP load (2004~2007, 2010, g/d) Fraser River (pg/L) Pacific Ocean (pg/L) Reference Dinn et al. (2012b) Dinn et al. (2012b) This study BDE-47 11.4 2.78 7.85 0.9 BDE-99 13.1 2.53 2.95 0 Table 3.16: PBDE daily load in the Fraser River. The Fraser River flow rate was measured at Environment and Climate Change Canada Station 08MF005 (Hope) on the day when sample was collected. The PBDE daily load is the sum of dissolved and particulate PBDE load by multiplying the concentration and the flow rate. Date Congener [Dissolved] [Particulate] Flow rate Dissolved daily load Particulate daily load Total daily load pg/L pg/L m3/s g/d g/d g/d 23-Jun-2017 BDE-47 8.28 36.21 6508 4.66 20.36 25.02 BDE-99 2.75 14.99 1.54 8.43 9.97 BDE-153 0.09* 0.98 0.05 0.55 0.60 BDE-209 20.21* 35.92 11.36 20.20 31.56 13-Feb-2018 BDE-47 7.38 1.00 798 0.51 0.07 0.58 BDE-99 3.15 1.29 0.22 0.09 0.31 BDE-153 0.12 0.14 0.01 0.01 0.02 BDE-209 4.93* 9.28 0.34 0.64 0.98 Note: * represents below LoD. 127 Table 3.17: Comparison of PBDE daily load in the Fraser River and Iona effluent. The PBDE daily load in the Fraser River is calculated in Table 3.16 while the Iona effluent daily load is available in Dinn et al. (2012b). Congener Fraser River total daily load Iona effluent daily load g/d g/d BDE-47 12.8 11.4 BDE-99 5.1 13.1 BDE-153 0.31 1.31 BDE-209 16.3 14.3 Table 3.18: Comparison of modelled results and actual results for BDE-47 and BDE-99. BDE-47 BDE-99 Location Model output (pg/L) Measured concentration (pg/L) Location Model output (pg/L) Measured concentration (pg/L) Upper SoG 6.5 165 Upper SoG 5.6 59 Lower SoG 6.4 141 Lower SoG 5.7 40 Upper HS 4.8 6.1 (composite) Upper HS 3.9 0.6 (composite) Lower HS 3.6 6.1 (composite) Lower HS 2.6 0.6 (composite) Upper JF 3.6 1.7 Upper JF 2.7 <LoD Lower JF 2.0 2.0 Lower JF 1.1 0.5 128 Chapter 4: Source, fractionation and fate of PCBs in the Strait of Georgia 4.1 Results 4.1.1 Data analysis The data reported by AXYS include 159 congeners or co-eluting congeners. Many of them were flagged with “<”, which represents “not detected at report limit”, and with “K” for “peak detected but did not meet quantification criteria, result reported represents the estimated maximum possible concentration”. Only some congeners have reliable data in most of the sample while many congeners cannot be quantified in many samples. The data analysis procedure of PCBs was the same as that of PBDEs (see Chapter 3.1.1). Limits of detection (LoD; pg) and limits of quantification (LoQ; pg) were determined based on the variability of laboratory blanks reported by AXYS with each batch of sample analysis. The final data set only reports PCB measurements (pg) that are above LoD or above LoQ. Cost of analysis prevents replication to evaluate analytical reproducibility. 4.1.2 Laboratory blanks, limits of detection and limits of quantification Similar to that of PBDEs, limits of detection (LoD) and limits of quantification (LoQ) of PCBs were calculated using laboratory analysis blanks reported by AXYS with each of the batch of samples (7 batches for dissolved PCBs; 6 batches for particulate PCBs). Outliers were defined as any number that is more than 1.5 interquartile range below the first quartile or above the third quartile, and were removed from the determination of LoDs and LoQs (Table 4.1). Limits of quantification spread widely among congeners, from 1 pg for dissolved CB-67 to 471 pg for dissolved CB-7 (Table 4.1), and from 2 pg for particulate CB-25 to 287 for particulate CB-3 (Table 4.1b). 4.1.3 Procedural blanks All procedural blanks, processed in the laboratory or at sea, were treated as regular samples by subtracting the corresponding laboratory analysis blank from the procedural blank, and comparing the value to the LoD and LoQ reported in Table 4.1 to determine whether the congener is detectable or quantifiable. 129 The dissolved PCB laboratory procedural blank prepared in 2013 (see Chapter 2 for details) did not yield any values above LoQ, except for five congeners or co-eluting congeners of tetra-CBs (CB-44+47+65, CB-45+51, CB-49+69, CB-50+53, and CB-68; Table 4.2a), which require procedural blank correction. The co-eluting CB-44+47+65 yielded the most prominent procedural blank (211 pg) in 2013. However, most of congeners were below LoD or between LoD and LoQ. Procedural blanks prepared in May 2017 with the CCGS John P. Tully’s Niskin bottles with different closing mechanism (see Chapter 2 for details) yielded more values above LoQ (Table 4.2a), indicating some level of tri-CBs contamination from these bottles (Figure 4.1). Although no PCB samples were collected during Line P cruise, these procedural blanks will be helpful to study PCBs in the Juan de Fuca Strait and Pacific Ocean in the future. Figure 4.1: Quantifiable PCB congeners measured in the procedural blank conducted in the sample preparation laboratory and using the CCGS John P. Tully’s Niskin bottles with different closing mechanisms (silicon tubing vs. springs closing mechanisms). Data in Table 4.2a. 130 The additional procedural blank conducted at sea in August 2018 onboard the CCGS Vector was also analyzed for PCBs (see Chapter 2 for details). Forty-six congeners out of 159 were above LoQ (Table 4.2b). We do not know whether this is an accidental contamination or the procedural blank is actually really at this level because no PCB samples were collected during the Vector cruise. However, this procedural blank may be helpful in future studies of PCBs in SoG. For particulate PCBs, only one procedural blank was prepared in the sample processing laboratory in December 2013 (see Chapter 2 for details). None congeners were above LoQ and only 3 congeners were detectable but not quantifiable (Table 4.2c). Based on this result, all particulate PCB data were corrected with the corresponding laboratory analysis blanks associated with the same batch of samples. 4.1.4 Temporal variability of PCB concentrations in the Strait of Georgia Time-series measurements were initiated in December 2013 to establish the temporal variability of PCBs concentration at Station S2, a station located close to Bowen Island, at the mouth of Burrard Inlet. Samples were collected over 3 consecutive years at ca. 50 m (Table 4.3a). Fifty-five dissolved PCB congeners could be quantified in all three samples, mostly tri-, tetra- and penta-CBs, and some of the di-, hexa- and hepta-CBs. Another forty-seven dissolved congeners could also be quantified in at least one of the three samples. In contrast to samples collected in 2014 and 2015, the sample collected in 2013 did not contain quantifiable dissolved octa-, nona-, and deca-CBs and only two hepta-CBs. Fewer congeners could be detected in particulate samples and, in contrast to dissolved PCBs, only one congener (PCB-83+99) could be quantified in all three samples (Table 4.3b). Even with a sample volume of 562 L, only a few congeners could be quantified ranging from tetra- to hepta-CBs in December 2013 (Table 4.3b). Although none of the di- and tri-CBs except CB-37 were above LoQs in 2013, most of these congeners were quantifiable even with only 163 L of sample in December 2015, indicating high particulate PCB concentrations. With a larger sample volume (711 L), most tri-, tetra- and penta-CBs could be measured above LoQs in October 2014. The large variations in volume filtered can produce a bias in the total particulate PCB concentrations since with smaller volumes, less congeners will be found at levels > LoD or 131 >LoQ and not included in the sum, resulting in an underestimation of the total particulate PCB concentration for smaller volume samples. Total dissolved and particulate concentrations of PCBs were calculated by adding the concentrations of all quantifiable congeners (Table 4.4). Total dissolved PCB concentration (Table 4.4a) gradually increased from 57 pg/L in 2013 to 112 pg/L in 2014 and 152 pg/L in 2015. Total particulate PCB concentrations were two orders of magnitude lower than total dissolved PCBs but also increased from 0.64 pg/L in 2013 to 1.9 pg/L in 2014 and 2.4 pg/L in 2015 (Table 4.4b). This trend cannot be attributed to sample volume since a smaller seawater volume was filtered in 2015. Due to the large number of PCB congeners detected in the samples, their concentrations were pooled into homolog groups based on their level of halogenation (Table 4.5). Only quantifiable congeners were included in the sums. For dissolved PCBs, there is a clear difference on homolog distribution between the lower concentration sample collected in 2013, which was strongly dominated by tetra-CB and the other two samples which were nearly equally dominated by tetra-, penta-, and hexa-CBs (Table 4.5a; Figure 4.2a). For particulate PCBs, there was a sharp contrast in homolog distribution between the lower concentration sample collected in 2013, which was dominated by penta- and hexa-CBs, and the other two samples which were dominated by tri-CBs (Table 4.5b; Figure 4.2b). While the homolog distribution of particulate PCBs was skewed towards the more hydrophobic congeners compared to the dissolved homolog distribution in the sample collected in 2013, as might be expected (see Chapter 4.3), the opposite was observed in the other two samples, where the maximum particulate homolog concentration was tri-CBs compared to penta-CBs for dissolved (Figure 4.2). Dissolved PCBs showed a strong temporal variability, especially hexa-CBs which increased 17 times from 2013 to 2015 (Figure 4.2a). Tri-, penta-, hexa-, hepta-, and nona-CBs increased continuously in the 3 years. Di- and octa-CBs had their highest concentrations mono-and tetra-CBs had the lowest concentrations in 2014. For particulate PCBs, di- and tri-CBs concentrations increased over the 3 years while hepta- and hexa-CBs showed the opposite trend (Table 4.2b). Other congeners either had their highest concentrations in 2014 (such as tetra- and penta-CBs) or their lowest (such as deca-CBs). 132 Figure 4.2: Dissolved (a) and particulate (b) PCB homolog concentrations at ~50 m at Station S2, at the mouth of Burrard Inlet, between 2013 and 2015. Data in Table 4.5. 4.1.5 Spatial variability of PCB concentrations in the Strait of Georgia Unlike PBDEs, PCBs were only measured once at Station S4-1.5 in August 2018 at 6 depths. Forty-six congeners, mostly tri-, tetra-, penta- and hexa- CBs could be quantified at all six depths (Table 4.6a). An additional sixteen congeners could also be quantified in at least one of the six samples. Congeners that could be quantified at Station S4-1.5 (Table 4.6a) were also almost always quantified at Station S2 (Table 4.3a). However, nearly all hepta-CBs and all the octa-, nona-, and deca-CBs, which were found at S2, were not quantifiable at S4-1.5. Particulate PCBs concentrations were measured at the same station and time but at two depths only (25 m and 50 m). Thirty-one congeners could be quantified at both depths and an additional eight congeners could be quantified at one depth (Table 4.6b). Total dissolved PCB concentrations, calculated by adding up the concentration of all quantifiable congeners in each sample (Table 4.7a), ranged from 24 pg/L to 80 pg/L, with two clear maxima at the surface and at 150 m depth (Figure 4.3). These concentrations were lower but overlapped with the concentration measured at Station S2 (57 – 152 pg/L). 133 Total particulate PCB concentrations were similar at both depths (2.1 pg/L at 25 m and 1.8 pg/L at 150 m) and much lower than total dissolved concentration (Figure 4.3), as observed at Station S2 (Figure 4.2). Total particulate concentrations at Station S4-1.5 were similar to those measured at Station S2 (0.64 – 2.4 pg/L). Figure 4.3: Depth profile of total dissolved and particulate PCB concentrations (calculated by summing up the concentrations of all quantifiable congeners) at Station S4-1.5 in August 2018. Data in Table 4.8. The concentration of dissolved congeners detectable at S4-1.5 ranged from 0.01 to 26.2 pg/L (Table 4.7a), while the particulate PCB congener concentration ranged from 0.002 to 0.18 pg/L. Dissolved PCB congeners concentrations averaged over the six depths at Station S4-1.5 versus over the 3 years of sampling at Station S2, showed slightly higher mono- and di-CBs concentrations at Station S4-1.5 than at S2, but much higher concentrations of tetra- to nona-CBs at S2 (Figure 4.4a). On the other hand, particulate congeners showed the opposite trend (Figure 4.4b). Mono, di, and tri-CBs occurred at higher concentration at S2, while the congeners with higher levels of chlorination were found at higher concentration at S4-1.5. 134 Figure 4.4: Average concentration of dissolved (a) and particulate (b) congeners measured in 2013 – 2015 at Station S2 (blue) and in 2018 at Station S4-1.5 (orange). Data in Table 4.5 and Table 4.8. 135 Calculating the average dissolved PCB congeners concentration detected at the six depths at Station S4-1.5 and at the three time points at Station S2, and pooling homologs confirm that dissolved PCBs found at Station S4-1.5 have lower level of chlorination than at station S2 (Figure 4.5a). The latter station has a maximum concentration of tetra-CBs, while Station S4-1.5 has maximum concentrations of di- and tri-CBs. For particulate PCBs (Figure 4.5b), the contrast is opposite, with particles at S4-1.5 having higher proportion of more chlorinated congeners (maximum penta-CBs at S4-1.5 vs tri-CBs at S2). We must remember, however, that the particulate PCB homolog distribution at Station S2 is temporally variable (Figure 4.2). Figure 4.5: Average dissolved (a) and particulate (b) PCB homolog concentration at Station S2 (blue, 3 year average) and S4-1.5 (orange, average of depth). Data in Table 4.5 and Table 4.8. Both dissolved and particulate PCB concentrations were measured at ca. 25 m and ca. 150 m at Station S4-1.5. At both depths, dissolved PCB were skewed towards lower homologs (Figure 4.6). While penta-CBs have the highest concentration in particulate PCB at both depths, dissolved PCBs were strongly dominated by tri-CBs at 25m and strongly dominated by mono- and di-CBs at 150m. This is similar to the trend found at Station S2 in 2013 (Figure 4.2). Since the hydrophobicity of PCB congeners increases with their degree of chlorination, this 136 fractionation of PCB congener between seawater and particles would be expected if the two PCB pools had the same point source. Figure 4.6: Dissolved vs particulate homolog concentrations at Station S4-1.5 at 25 m (a) and 150 m (b) depth. Data in Table 4.8. The depth profiles of dissolved PCBs congeners varied with the level of congener chlorination (Figure 4.7). The depth of subsurface maximum concentration of mono- and di-CBs were found at ~150 m depth while it was at ~75 m for the more chlorinated congeners, a similar trend as observed for dissolved PBDEs. The concentration of dissolved PCBs also increased toward the surface except for mono-CBs. 137 Figure 4.7: Depth profiles of dissolved PCB congeners at S4-1.5 in August 2018. The total concentration of each congener group only includes congeners that are quantifiable (>LoQ). Data in Table 4.8a. The distribution of dissolved PCB homologs at Station S4-1.5 were similar at all depths, with a maximum concentration in tri-CBs, except for the sample taken at ca. 150 m, which contained much higher mono- and di-CBs (Figure 4.8a). In contrast, the distribution of particulate PCB homologs has a maximum concentration in penta-CBs at 25 m and 150 m (Figure 4.8b). Compared with the concentration reported in literature, the concentrations of total dissolved PCBs are at the same level as those in the Boundary Passage, Rosario Strait and Johnstone Strait (Frouin et al., 2013). 138 Figure 4.8: Dissolved (a) and particulate (b) homolog distribution at different depths at Station S4-1.5. Data in Table 4.8. 4.1.6 Sources of PCBs to the SoG Unlike PBDEs, PCBs are legacy pollutants that have been recycled in the environment since their production ban 50 years ago. Since they are not presently used in domestic products, it is unlikely that wastewater treatment plants would be a significant point source. Instead, PCB sources are much more diffuse as they are being transported over long distances through the atmosphere (Gouin et al., 2004). However, previously contaminated sites, as the industrial areas surrounding Burrard Inlet, could still act as point sources. This possibility is supported by the PCB distribution in SoG sediments (Grant et al., 2011). 4.1.6.1 Iona effluent plume Dissolved and particulate PCBs concentrations were analyzed only once in the Iona plume (Station S1) in December 2013 and October 2013, respectively. For dissolved PCBs, fifty-139 seven congeners can be quantified with another 26 congeners detectable but not quantifiable (Table 4.9a). No nona- and deca-CBs were quantified at S1. All quantifiable congeners at S1 were also quantified at S2 but S2 had more congeners above LoQ. For particulate PCBs, eighty-three congeners were above LoQ and twenty-nine congeners between LoD and LoQ (Table 4.9b). No mono- and di-CBs were quantifiable. In contrast to dissolved PCBs, forty particulate congeners quantifiable at S1 could not be quantified at S2. Most of these congeners are hexa-, hepta-, and octa-CBs. Total dissolved PCB concentrations were calculated based on all congeners that were quantifiable (Table 4.10a). The Iona plume had a total PCBs concentration of 36.9 pg/L, which was lower than the concentration measured at S2 (57-152 pg/L; Table 4.4a) but within the range of concentration measured at S4-1.5 (23.5 – 80 pg/L; Table 4.7a). The total particulate PCBs were calculated in the same way as total dissolved PCBs (Table 4.10b). The total particulate concentrations (9.3 pg/L) at the Iona plume was ~5 times lower than the dissolved concentration in the plume (36.9 pg/L). However, this particulate PCB concentration was still higher than at S2 (0.64-2.4 pg/L) and S4-1.5 (1.8-2.1 pg/L). For individual congeners that are detectable, the dissolved concentrations at the Iona plume ranged from 0.01 to 9.3 pg/L while particulate concentrations were between 0.001 and 0.59 pg/L. While dissolved PCBs at S1 were dominated by tetra-CBs, penta- and hexa-CBs were dominant at S2 (Figure 4.9a). Particulate PCBs had an opposite distribution to dissolved PCBs. S1 was dominated by higher chlorinated congeners such as penta- and hexa-CBs, while S2 was dominated by lower chlorinated congeners, including tetra- and tri-CBs (Figure 4.9b). 140 Figure 4.9: Dissolved (a) and particulate (b) congeners concentrations (pg/L) measured in 2013 at Station S1 (orange) and average concentration between 2013 and 2015 at Station S2 (blue). Data in Table 4.5 and Table 4.11. 141 Grouping homolog confirmed that dissolved PCBs at S1 had much lower concentrations of the more chlorinated homologs (penta- to nona-CBs) than the average at S2. However, the concentrations of the less chlorinated homologs were similar at S1 and S2 (Table 4.11a; Figure 4.10a). In contrast, particulate PCB homolog distribution showed the opposite trend (Table 4.11b; Figure 4.10b), with penta- to octa-CBs found at much higher concentration at S1 than at S2. Figure 4.10: Dissolved (a) and particulate (b) PCB homolog concentration at Station S2 (blue; average of 3 measurements in December 2013, October 2014 and December 2015) versus S1 (orange; December 2013). Data in Table 4.5 and Table 4.11. 4.1.6.2 Burrard Inlet To investigate the importance of Burrard Inlet as a PCB source, a dissolved and a particulate sample were collected in the Inner Harbor near the Port of Vancouver (Station S3, Figure 2.1a) in December 2014, and two dissolved and particulate samples were collected in the Central Harbor near the industrial zones (Station S3b, Figure 2.1a) in December 2015 and August 2016. Dissolved PCBs in Inner Harbor (S3) had 115 congeners above LoQ (Table 4.9a). The two measurements at Central Harbor (S3b) had 74 congeners quantifiable in both samples and 142 another 13 congeners below detection limit. Some congeners quantifiable in Burrard inlet could not be quantified at S2. Compared to dissolved PCBs, particulate PCBs at S3 had fewer congeners above LoQ (78) and between LoD and LoQ (24; Table 4.9b). Seventy particulate congeners were quantifiable in both samples. Most of the highly chlorinated congeners that were quantifiable in S3 and S3b could not be quantified at S2. The total dissolved PCB concentrations at S3 and S3b were 187 and 130-139 pg/L, respectively, which were similar to the highest concentrations measured at S2 (57-152 pg/L) but higher than at S1 (36.9 pg/L), and S4-1.5 (23.5-80.0 pg/L; Table 4.10a). Compared with dissolved PCBs, the total particulate PCB concentrations at S3 and S3b were 25.8 and 19.3-58.7 pg/L, respectively (Table 4.10b), much lower than the dissolved PCBs concentrations. However, these concentrations were higher than at S1 (9.3 pg/L), S2 (0.64-2.4 pg/L), and S4-1.5 (1.8-2.1 pg/L). The average dissolved homolog distribution at Station S2 and S3b were dominated by tetra- and penta-CBs, as at Station S3, although their concentrations were higher at S3 (Figure 4.11a). The Central Harbor (S3b), however, is receiving an additional source of octa- and nona-CBs. In contrast, the homolog distribution of particulate PCBs is dominated by penta- and hexa-CBs in Burrard Inlet (Figure 4.11b), but strongly skewed towards tri-CBs at S2, where particulate PCB concentrations are much lower. 143 Figure 4.11: Average dissolved (a) and particulate (b) PCB homolog concentrations (pg/L) at Station S2 (Bowen Island), S3 (Inner Harbor) and S3b (Central Harbor). Data in Table 4.5 and Table 4.11. There is also a strong temporal variability in the concentration and homolog distribution of PCBs at S3b. While dissolved PCB concentrations were similar during both years (December 2015 and August 2016) of sampling, their homolog distributions were very different and dominated by penta-CBs in 2015 and octa-CBs in 2016. As for PBDEs, particulate PCB concentrations were higher in 2015, reflecting sampling during tidal resuspension of shallow contaminated sediments, but their homolog distribution were more similar both years and dominated by penta- and hexa-CBs (Figure 4.12). 144 Figure 4.12: Dissolved (a) and particulate (b) PCB concentrations (pg/L) quantified at S3b (Central Harbor in the Burrard Inlet) in December 2015 and August 2016. Data in Table 4.11a. 4.2 Discussion 4.2.1 Working hypothesis Although the manufacture of PCBs has been banned 5 decades ago, legislation has allowed continued use of machineries and equipment containing PCBs until the end of their service life (Agrell et al., 2004). Therefore, although their inventories and concentrations have been decreasing in the last decades (Johannessen et al., 2008b), PCBs continue to be released in the environment as a result of leaching from formerly contaminated sites, leakage from aging machineries, or improper disposal and storage. Once released, the more volatile congeners are preferentially dispersed through the atmosphere, resulting in their global distribution at low concentration. On the other hand, the less volatile congeners remain confined in the more immediate proximity of their release points, and are found at higher concentrations in soils or sediments. A fraction of these congeners could also be released to and dispersed by water before burial. Such release is expected to be more effective for the less hydrophobic congeners. In aquatic systems, as in the SoG, it is expected that desorption of PCBs from particles would occur initially in sediment pore waters, increasing PCB pore water concentrations until equilibrium is reached and driving a diffusive flux of dissolved PCBs into bottom water. During sporadic 145 sediment resuspension (by storms, dredging, etc.), PCBs dissolved in pore waters would be rapidly released into the water column and contaminated particles would desorb more PCBs on account of the lower dissolved PCB concentrations in bottom waters compared to pore waters. This release would be less pronounced, however, during regularly recurring sediment resuspension (e.g. by tidal currents), since pore water concentration would not be able to build up. Successive resuspensions of contaminated sediments over time should shift PCB congeners distribution in particles towards the more chlorinated homologues, while the PCB congener distribution in the ambient water would be fractionated with respect to the resuspended sediments towards the less chlorinated homologues. Note however, that congener distribution of both resuspended sediments and ambient water would shift with time towards homologs with higher level of chlorination, as the less chlorinated congeners are released preferentially and dispersed by currents. The PCB congeners dispersed by current will eventually be scavenged by “clean” particles back to the sediment. This process is also expected to fractionate PCB congeners, and the less chlorinated PCBs are expected to be distributed over a wider range at lower concentrations. Since most of the manufactured PCBs were used in industrial applications (such as in large volume electrical transformers and capacitors, hydraulic fluids, adhesives, and inks, with the exception of sealants and paints used in construction), effluents from wastewater treatment plants in urban areas (such as the Iona outfall) are not expected to be major point sources to ambient waters. Instead, long range transport and atmospheric deposition or soil leaching and spills from industrial zones are expected to be more dominant (Dachs et al., 2002; Dalla Valle et al., 2005). For the SoG, the distribution of PCB concentration in sediment has identified Burrard Inlet as an entry point of PCBs in the SoG (Grant et al., 2011). This is consistent with the continued presence of the Port of Vancouver and industrialized zones on the shores of this inlet during the last century. 4.2.2 Partitioning of PCBs between dissolved and particulate phases in the water column of the SoG The percentage of the total PCB load associated with particles in seawater varied with location (Table 4.12). The percentage of total particulate PCB is relatively high in the Iona 146 plume (20%; although dissolved and particulate PCB concentrations were not measured on the same date) and in Burrard Inlet (12 – 30%), compared to Station S2 at ca. 50 m (ca. 1 – 2%) and Station S4-1.5 at 150 m (ca. 2%). At Station S4-1.5 at 150 m, % particulate PCB was intermediate (ca. 7%). The % particulate PBDEs was also high in the Iona plume (ca. 40%) but the particulate PCB/particulate PBDE ratio was low (0.05), confirming that the Iona outfall is a more important source for particulate PBDEs than for particulate PCBs (Table 4.12). In Burrard Inlet, the % particulate PBDE was also high during tidal sediment resuspension (63%), but much lower otherwise (<10%). Invariably, however, the particulate PCB/particulate PBDE ratio was much higher than at S1 (>0.5 vs 0.05), indicating that contaminated sediment from the Central Harbor is a more important source for particulate PCBs than particulate PBDEs (Table 4.12). This is consistent with the higher ∑[PCB]/∑[PBDE] measured in sediments of Burrard Inlet in 2003 (4.3, 1.3) compared to sediments collected near the Iona outfall (0.1; Grant et al., 2011), which further illustrates the contrasting sources of the two POPs. While both Burrard Inlet and the Iona effluent are significant sources of particulate PBDEs to the SoG, particulate PCBs is more exclusively originating from Burrard Inlet. The relatively higher PCB/PBDE measured in sediment compared to suspended particles may be due to PCBs being more concentrated in coarser particles, which are less easily transported by tidal current and are therefore older. At Station S2, although there was a relatively low and constant % particulate PCBs (1 – 2%), the % particulate PBDE was high (27%) in December 2013 or low and similar to that S4-1.5 (<1%) in 2014 and 2015 (Table 4.12). When % particulate PBDE was high (2013; 27%), particulate PCB/particulate PBDE ratio was very low (0.01) confirming that the high particulate load found at Station S2 at that time originated from the southern SoG influenced by the Iona outfall. When % particulate PBDE was low (2014 & 2015; <1%), particulate PCB/particulate PBDE was much higher (>1) and closer to the ratios observed in Burrard Inlet (>0.5), suggesting a stronger influence of particles originating from this industrialized area. Similarly, dissolved PCB/dissolved PBDE were higher in Burrard Inlet than at S1 and S4-1.5, while at S2, the ratio was low in 2013 and higher in 2014 and 2015 (Table 4.12), which is consistent with a stronger influence of seawater originating from Burrard Inlet in 2014 and 2015. This explanation is supported by the time of sampling with respect to tides. Sampling in 2013 was conducted just after high tide and tidal current had been entering Burrard Inlet, while sampling in 2014 and 147 2015 were conducted in the middle and at the end of ebbing tide, when the tidal currents were flowing from Burrard Inlet. These observations are thus consistent with predictions on the relative importance of outfalls and industrialized areas as point sources of PCBs. In August 2018 the % particulate PCBs at Station S4-1.5 was ca.7%, at 25m and ca. 2% at 150m (Table 4.12), which is higher than the % particulate PBDEs (<1%,), indicating that PCBs, although mostly found in “dissolved” form in the southern SoG, had a higher particulate fraction, possibly reflecting their more hydrophobic nature, as the less hydrophobic congeners have been released from particles and dispersed by currents and atmosphere during the last 50 years. If PCBs originated from a unique source or if dissolved and particulate PCBs collected in a sample of seawater had been in contact for long enough to reach equilibrium, an increase in % particulate with level of chlorination would be expected, reflecting their hydrophobicity. This trend was confirmed at Station S4-1.5 (Figure 4.13a) but not in Burrard Inlet (Figure 4.13b). In the latter, the variation in % particulate for different homologues is highly variable, suggesting the presence of multiple sources into the inlet with different congener distribution and different partitioning between dissolved and particulate forms. Industrial applications of PCBs are in part dictated by their physical state, which range from waxy material for the more chlorinated congeners to light oil for the less chlorinated (Borja et al., 2005). These different applications were likely distributed at different locations around Burrard Inlet resulting in multiple point sources which cannot uniformly mix within the inlet. 148 Figure 4.13: % particulate for PCB homologs (a) at southern SoG (S4-1.5 in August 2018), (b) Burrard Inlet (S3: Inner Harbor in December 2014, S3b: Central Harbor in December 2015 and August 2016), (c) Iona effluent plume (S1 in December 2013), (d) Bowen Island (S2 in December 2013, October 2014 and December 2015). Data in Table 4.12. In contrast, at Station S1, within the Iona plume, the expected trend is generally followed (Figure 4.13c) and at Station S2, it is only followed when sampling occurred just after flood tide and tidal currents were flowing towards Burrard Inlet, as in 2013 (Figure 4.13d). This observation thus confirms that the water sampled in 2013 was mostly water from the SoG influenced by the Iona outfall, which is consistent with the low particulate and dissolved PCB/PBDE ratios observed at that time (Table 4.12). When particulate and dissolved PCB/PBDE ratios are higher at that location (2014, 2015), indicating a source from Burrard Inlet, the increasing trend in % particulate with degree of chlorination is not observed, as is the case at Station S3 and S3b. The trend observed at Station S4-1.5 and S1 suggest that, at these 149 locations, dissolved and particulate PCBs have had sufficient time to regain or approach equilibrium with respect to adsorption. Bowen Island (Station S2) connects the Iona plume, Burrard Inlet and southern SoG through water circulation. Water from Burrard Inlet and the Iona plume pass by S2 before arriving at S4-1.5. Thus, it is meaningful to compare the congener ratios at S2 with other stations. The calculated particulate tri-/penta-CB ratios and tri-/hexa-CB ratios are low in Burrard Inlet, high in Bowen Island, but low in southern SoG again (Table 4.13). This is consistent with the adsorption and desorption of different congeners. Once the particles are released into the Burrard Inlet, low chlorinated congeners desorb from particles faster than high chlorinated congeners, leading to the low ratio. During the way to Bowen Island, the high chlorinated congeners have more time to desorb from particles, leading to lower particulate concentrations and rising the ratio. When particles eventually arrive at the central SoG, PCB adsorption to particles happens, which increases the particulate concentrations of high chlorinated congeners first and lowers the ratio. The opposite trend is also observed for the dissolved tri-/penta-CB ratios and tri-/hexa-CB ratios, but the difference between S2 and S3/S3b is not apparent (Table 4.14). The ratio at S4-1.5 is several times higher than that in other stations, especially near the surface, which may suggest atmospheric deposition of low chlorinated congeners. 4.2.3 Spatial variations of dissolved and particulate PCB concentration in the SoG The spatial distribution of PCB concentration in seawater can also provide insight into the locations of the point of entry of these contaminants. The database for PCBs is more limited than for PBDEs, as PCBs were only measured multiple times at Station S2 and S3b, and only once at Stations S1, S3 and S4-1.5. Nonetheless, summing up all the concentrations of quantifiable and detectable congener concentrations showed clear spatial variations, similar to those found with PBDEs, which confirm the sources of PCBs into the SoG. The total particulate PCB concentration measured in the effluent plume near the Iona Island diffusers (Station S1; 9 pg/L) was ca. five times higher than measured in the seawater of the southern SoG at Station S4-1.5 (1.8 – 2.1 pg/L; Table 4.12), suggesting that the Iona effluent could only be a modest source of particulate PCBs in the SoG. At Station S2, where PCB 150 concentration was measured once in three consecutive years, the total particulate PCB concentration was particularly low (0.6 pg/L) in 2013, when sampling was conducted just after high tide, which resulted in collecting water from the southern SoG influenced by the Iona effluent (and explaining the relatively high particulate PBDE concentration measured in the same sample). On the other hand, when particulate PCB concentrations were higher in 2014 and 2015 (1.9 and 2.4 pg/L, respectively), sampling was conducted in the middle and at the end of ebbing tide, so that the sampled water was more influenced by water ebbing from Burrard Inlet, which also explain the relatively high particulate PCB/particulate PBDE ratio in these samples and the lack of systematic increase in %particulate PCB with degree of chlorination. Concentrations of particulate PCB were two to six times higher in Burrard Inlet (19 -59 pg/L) than within the Iona plume (Table 4.12), further confirming this Burrard Inlet as a more important entry point of particulate PCB to the SoG. As for particulate PBDE, the highest particulate PCB concentration at Station S3b was found during periods of higher tidal currents in 2015. The total dissolved PCB concentration measured at Station S1 (37 pg/L) was within the range of concentrations measured at Station S4-1.5 (24-80 pg/L), indicating that the Iona outfall cannot be a direct point source of dissolved PCB in the SoG. Higher dissolved PCB concentrations were measured in Burrard Inlet (130-139 pg/L) indicating that industrialized zones on the shores of this inlet can be a more important source of dissolved PCB as well as particulate PCB to Burrard Inlet. This is consistent with the higher dissolved PCB concentrations measured at Station S2 in 2014 (112 pg/L) and 2015 (152 pg/L) during ebb tide and lower concentration measured in 2013 (57 pg/L) during flood tide. However, considering the relatively small difference in concentration between Burrard Inlet and the southern SoG (S4-1.5), Burrard inlet cannot be the only source of PCB. Using the SoG box model (Figure 2.2), the minimum input rate of PCBs to be added to the Strait to reach the measured dissolved PCB concentrations can be estimated, assuming no removal by scavenging. In a first experiment, Victoria’s and Vancouver’s effluent input of 2003 reported by Dinn et al. (2012b) were added to the lower HS and lower SoG boxes, respectively. Similar to that of PBDEs, this experiment produced concentrations (Table 4.15) that were one order of magnitude lower than measured at Station S4-1.5 in 2018 (Figure 4.14) and in Haro Strait in 2005 (Frouin et al., 2013), confirming that wastewater treatment plants from large urban 151 areas are not the primary source of PCB to the Salish Sea and could only account for, at most, ca. 10% of the total input. In the second experiment, adding another source ca. 7.5 times higher than the effluent input (ca. 50 g/d) to the upper SoG box generates concentration similar to observations both in the SoG and in HS (Table 4.15; Figure 4.14). Such input could represent addition of PCB to the SoG from Burrard Inlet and the Fraser River. If coming entirely from the Fraser River, the PCB concentration of the Fraser river would have to be 220 pg/L, similar to what has been measured in Burrard Inlet. If the Fraser River was indeed the main source, contributions from Burrard Inlet would, of course, have to be proportionally lower. At this point, we cannot further constrain the sources of PCB to the SoG as time series measurements are needed in the Fraser River and Burrard Inlet. For the latter, estimating the rate of addition of PCB into the Burrard Inlet could be done by measuring PCB concentrations in seawater and the tidal flow at the mouth of the inlet over the tidal cycle, which may prove difficult considering the cost of PCB analysis. Figure 4.14: Output results from the box model under different conditions: (a) with the input from Victoria and Vancouver WWTPs added to the lower HS and lower SoG boxes, respectively (Dinn et al., 2012b), and (b) the same inputs from the previous scenario with additional 50 g/d input to the upper SoG box. SoGu and SoGl represent upper and lower Strait of Georgia, respectively. HSu and HSl represent upper and lower Haro Strait, respectively. JdFSu and JdFSl represent upper and lower Juan de Fuca Strait, respectively. 4.2.4 PCB homologs in the Strait of Georgia The distribution of PCB homologs could provide further insight on the sources of PCB and on the processes affecting their distribution during dispersal. 152 4.2.4.1 Dissolved PCB homologs The PCB homologs distribution observed at Station S2 in 2013 is quite different from the distribution observed in 2014 and 2015 (Figure 4.15). In 2013, the tetra-CB were more sharply dominant, while in 2014 and 2015, the homologs distribution showed a broader maximum of tetra-, penta-, and hexa-CBs. Figure 4.15: Dissolved homolog PCB distribution at (a) Station S2 in 2013, (b) Station S1, (c) Station S2 in 2014 and 2015, (d) Station S3. Data in Table 4.5a and Table 4.11a. The homologs distribution observed at S2 in 2013 is more similar to the homolog distribution measured in the Iona plume (S1; Figure 4.15). On the other hand, the broader distribution observed at S2 in 2014 and 2015 is more consistent with the distribution of congeners at S3, suggesting a stronger influence from Burrard Inlet (Figure 4.15). In addition, the bimodal distribution observed at S2 in 2014 suggests some contribution from the Central Harbor of Burrard Inlet (Station S3b; Figure 4.16). While these similarities may be fortuitous, they are in agreement with and reinforce the earlier deduction, based on particulate and dissolved 153 PCB/PBDE concentration ratios (Table 4.12) and % particulate of PCB homologs (Figure 4.13), that there was a stronger influence from the Iona outfall at Station S2 in 2013, when sampling was conducted just after flood. Figure 4.16: Dissolved PCB homologs distribution at Station 2 in October 2014 and Station 3b in December 2015 and August 2016. Data in Table 4.5a and Table 4.11a. The sharp difference in the PCB homolog distribution measured at Station S3b in December 2015 and August 2016 (Figure 4.12) further illustrates the complexity of PCB input into Burrard Inlet. Such variability is clearly obscuring the processes that regulate the dispersal and fate of PCBs discharged in the Inlet. Identifying and monitoring specific point sources and their dispersal by currents is necessary to take into account this variability. A striking difference was also observed between the average dissolved PCB homologs distribution measured at five of the six depths in the water column at S4-1.5 (the sample at 150 m was not included in the average because of its anomalously high concentration in mono- and di-CB; Figure 4.8) and the average dissolved PCB homologs distribution measured at S2, clearly showing the preferential removal of dissolved tetra- to nona-CBs during dispersion from the entrance of Burrard Inlet to the southern SoG (Figure 4.17). In contrast, the mono- to tri-CBs remained at the same concentration levels or increased, indicating addition from another source, possibly the atmosphere. At this point, it is difficult to assess the significance of and the reason for the large increase in dissolved mono- and di-CBs concentration found at 150 m at Station S4-1.5 (Figure 4.7; Figure 4.8). 154 Figure 4.17: Averaged dissolved PCB homologs distribution observed at Station S4-1.5 from all depth except 150 m in August 2018 and S2 in December 2013, October 2014 and December 2015. Data in Table 4.5a and Table 4.8a. 4.2.4.2 Particulate PCB homologs There was also a sharp different in particulate PCB homologs distribution at Station S2 between 2013 and 2014/2015 (Figure 4.18). The lower particulate PCB concentration measured in December 2013 had a homolog distribution with a broad maximum in penta- and hexa-CBs, while the samples collected in 2014 and 2015, which are thought to represent a dominant input from Burrard Inlet, are more sharply dominated by the tri-CBs, particularly in 2015. However, the particulate PCB homolog distribution at S1 and S3 are similar and cannot be used to discriminate between these two sources (Figure 4.18). The particulate PCB homolog distribution observed at Station S2 in 2014 and 2015 cannot be explained at this point. The average particulate PCB homolog distribution measured at S2 and at 25m and 150 m depth at Station S4-1.5 suggest that the relatively high fractions of di- and tri-CBs found at S2 are preferentially lost, possibly as a result of desorption, during dispersion of particles from Burrard Inlet, through Bowen Island, into the southern SoG (Figure 4.19). 155 Figure 4.18: Particulate homolog PCB distribution at (a) Station S2 in 2013, (b) Station S1, (c) Station S2 in 2014 and 2015, (d) Station S3. Data in Table 4.5b and Table 4.11b. Figure 4.19: Particulate homolog PCB distribution at (a) Station S2 (average 2013 – 2015), (b) Station S4-1.5. Data in Table 4.5b and Table 4.8b. 156 Table 4.1: Laboratory analysis blanks reported by AXYS for different batches of dissolved (a) and particulate (b) PCB analysis. Dates are sampling times of samples included in each batch of analysis. Grey cells are data more than 1.5 interquartile range either below the first quartile or above the third quartile, which are considered outliers and removed before calculating LoD and LoQ. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K); red = data not quantifiable (NQ). (a) Congener Class Axys ID WG45312-101 L WG46585-101 L WG49873-101 WG54477-101 WG59905-101 WG63110-101 WG66480-101 Average (w/o outlier) LOD LOQ WORKGROUP WG45312 WG46585 WG49873 WG54477 WG59905 WG63110 WG66480 Sample Size 1sample 1sample 1sample 1sample 1sample 1sample 1sample UNITS pg pg pg pg pg pg pg pg pg pg Mono PCB-1 9.2 4.84 4.93 7.17 5.02 5 4.28 5.8 5 18 PCB-2 5.24 5.46 2.76 6.95 3.03 2.74 2.48 4.1 5 18 PCB-3 8.4 7.52 5.66 33.1 7.47 27 13.8 14.7 33 109 Di PCB-4 22 38 8.6 19 3.95 7.62 7.29 15.2 36 120 PCB-5 12.4 27 8.2 12 2 3.6 6 7.4 13 43 PCB-6 10.6 24 7.2 29.9 1.8 3.74 5.4 11.8 31 103 PCB-7 10.6 25 7.1 2260 18.2 63.6 129 42.3 141 471 PCB-8 9.4 22 6.5 16.9 8.09 16.6 21.1 14.4 19 63 PCB-9 10.8 23 6.9 11 1.8 3.1 5.3 8.8 21 72 PCB-10 10.6 24 6.4 11 1.8 3.3 5.3 8.9 22 75 PCB-11 38 40.2 28.7 117 36.1 71.3 26.1 51.1 98 326 PCB-12 + 13 11.2 25 8.3 11 1.9 3.3 5.7 6.9 12 39 PCB-14 11 25 7.6 11 1.8 3.2 5.6 6.7 12 39 PCB-15 14.4 23 9.8 11 3.94 8.06 7.4 11.1 19 62 Tri PCB-16 3.1 2.8 3 6.54 2.77 7.51 7.67 4.8 7 23 PCB-17 3.8 2.4 2.6 5.48 3.23 8.61 8.59 5.0 8 27 PCB-18 + 30 5.08 3.63 3.85 19 5.58 22.2 21.9 11.6 27 89 PCB-19 2.4 3.1 3.33 8.01 1 1.52 2.34 2.3 3 9 PCB-20 + 28 10.64 5.32 6.32 25.8 7.41 22 14.6 13.2 24 80 157 Congener Class Axys ID WG45312-101 L WG46585-101 L WG49873-101 WG54477-101 WG59905-101 WG63110-101 WG66480-101 Average (w/o outlier) LOD LOQ WORKGROUP WG45312 WG46585 WG49873 WG54477 WG59905 WG63110 WG66480 Sample Size 1sample 1sample 1sample 1sample 1sample 1sample 1sample UNITS pg pg pg pg pg pg pg pg pg pg PCB-21 + 33 4.7 2.8 2.6 14.6 4.23 12.7 8.29 7.1 15 49 PCB-22 3.44 2.3 2 9.36 2.93 7.22 5.83 4.7 8 28 PCB-23 1.34 2.3 1.8 1.8 1 1 1 1.5 2 5 PCB-24 1.58 1.9 1.9 1.6 1 1 1 1.4 1 4 PCB-25 1.12 1.9 1.5 1.5 1 1.39 1 1.3 1 3 PCB-26 + 29 1.58 2.2 1.8 9.85 1.21 3.77 2.95 2.3 3 10 PCB-27 1.48 1.7 1.8 2.35 1 1.1 1 1.5 2 5 PCB-31 7.46 3.11 5.44 19.6 6.46 19 13.4 10.6 20 67 PCB-32 1.62 2.1 1.89 5.09 2.5 4.82 4.28 3.2 4 15 PCB-34 1.48 2.2 1.8 1.7 1 1 1 1.5 1 5 PCB-35 1.52 2.3 2.2 2.29 1 1 1 1.6 2 6 PCB-36 1.36 2.1 1.9 1.5 1 1 1 1.4 1 5 PCB-37 2.5 2.1 2.4 4.86 1.76 3.65 2.62 2.8 3 11 PCB-38 1.42 2.2 2 1.5 1 1 1 1.4 1 5 PCB-39 1.34 2.1 1.9 1.6 1 1 1 1.4 1 5 Tetra PCB-40 + 41 + 71 4.9 2.4 1.8 7.67 3.45 5.42 5.67 4.5 6 21 PCB-42 1.76 1 1.9 3.6 1.43 2.69 1.76 2.0 3 9 PCB-43 2 1 2.1 2 1 1.1 1 1.5 2 5 PCB-44 + 47 + 65 10.06 9.7 7.33 18.6 16.1 13 17.4 13.2 13 43 PCB-45 + 51 1.88 2.67 1.7 3.81 3.5 3.85 3.55 3.0 3 9 PCB-46 2.2 1 2 2 1 1 1.14 1.5 2 6 PCB-48 1.82 1.18 1.8 3.27 1.42 2.68 2.34 2.1 2 7 PCB-49 + 69 4.9 2.96 2.31 7.61 3.8 5.19 4.84 4.5 5 17 PCB-50 + 53 1.8 1 1.6 1.6 1 1.38 1.5 1.4 1 3 PCB-52 9.56 5.18 9.18 18.7 7.57 12.6 8.73 10.2 13 44 158 Congener Class Axys ID WG45312-101 L WG46585-101 L WG49873-101 WG54477-101 WG59905-101 WG63110-101 WG66480-101 Average (w/o outlier) LOD LOQ WORKGROUP WG45312 WG46585 WG49873 WG54477 WG59905 WG63110 WG66480 Sample Size 1sample 1sample 1sample 1sample 1sample 1sample 1sample UNITS pg pg pg pg pg pg pg pg pg pg PCB-54 1.38 1 1.5 1.3 1 1 1 1.2 1 2 PCB-55 1.86 1 1.5 1.4 1 1 1 1.3 1 3 PCB-56 3.26 3.71 1.4 3.71 1.68 2.12 1.57 2.5 3 10 PCB-57 1.9 1 1.3 1.3 1 1 1 1.1 0 2 PCB-58 1.88 1 1.4 1.4 1 1 1 1.2 1 3 PCB-59 + 62 + 75 1.38 1 1.4 1.3 1 1 1 1.2 1 2 PCB-60 2 2.12 1.4 2.9 1 1.62 1 1.7 2 7 PCB-61 + 70 + 74 + 76 15.94 9.49 7.04 16 6.75 9.06 6.62 10.1 12 41 PCB-63 1.78 1 1.3 1.3 1 1 1 1.2 1 3 PCB-64 3.06 1.88 1.3 5.31 2.24 3.81 3 2.9 4 13 PCB-66 7.28 4.29 2.92 7.53 2.82 4.76 2.73 4.6 6 21 PCB-67 1.58 1 1.2 1.2 1 1 1 1.1 0 1 PCB-68 1.76 1.96 1.3 1.46 1.67 1 3 1.7 2 6 PCB-72 1.66 1 1.2 1.3 1 1 1 1.2 1 2 PCB-73 1.38 1 1.3 1.3 1 1 1 1.1 1 2 PCB-77 2.2 1 1.5 1.4 1 1.18 1.09 1.3 1 4 PCB-78 1.94 1 1.6 1.3 1 1 1 1.3 1 4 PCB-79 1.6 1 1.3 1.1 1 1 1 1.1 1 2 PCB-80 1.74 1 1.3 1.2 1 1 1 1.2 1 3 PCB-81 2 1 1.4 1.4 1 1.1 1 1.3 1 4 Penta PCB-82 2.2 3.6 2.2 2.1 1 1 1.1 1.9 3 9 PCB-83 + 99 4.54 6.47 6.82 4.66 3.1 2.71 2.67 4.4 5 17 PCB-84 2.4 3.7 2.1 2.57 2.03 1 1.63 2.2 3 8 PCB-85 + 116 + 117 2.12 2.7 1.6 1.69 1.23 1 1.28 1.7 2 6 159 Congener Class Axys ID WG45312-101 L WG46585-101 L WG49873-101 WG54477-101 WG59905-101 WG63110-101 WG66480-101 Average (w/o outlier) LOD LOQ WORKGROUP WG45312 WG46585 WG49873 WG54477 WG59905 WG63110 WG66480 Sample Size 1sample 1sample 1sample 1sample 1sample 1sample 1sample UNITS pg pg pg pg pg pg pg pg pg pg PCB-86 + 87 + 97 + 108 + 119 + 125 7.4 9.93 3.77 8.95 5.19 3.61 4.54 6.2 8 26 PCB-88 + 91 1.98 3.1 1.8 1.9 1 1 1.2 1.7 2 7 PCB-89 2.2 3.4 1.9 2 1 1 1 1.8 3 9 PCB-90 + 101 + 113 8.1 6.87 9 12.1 5.16 4.31 4.62 7.2 8 28 PCB-92 2.28 3.2 1.8 1.9 1 1 1.38 1.8 2 8 PCB-93 + 95 + 98 + 100 + 102 9.32 7.91 3.83 11.8 5.58 6.27 5.95 7.2 8 27 PCB-94 2 3.4 1.9 2.1 1 1 1 1.8 3 9 PCB-96 1.4 1.7 1.6 1.4 1 1 1 1.3 1 3 PCB-103 1.68 2.8 1.5 1.7 1 1 1 1.5 2 6 PCB-104 1.38 1.8 2.1 1.2 1 1 1 1.4 1 4 PCB-105 4.7 4.92 1.6 3.11 1.94 1.6 2.18 2.9 4 14 PCB-106 1.38 2.8 1.6 1.8 1 1.6 1 1.6 2 6 PCB-107 + 124 1.52 3 1.8 1.9 1 1.7 1 1.7 2 7 PCB-109 1.46 2.6 1.7 1.7 1 1.5 1 1.6 2 5 PCB-110 + 115 8.64 9.16 7.03 11.2 5.26 2.9 4.49 7.0 9 29 PCB-111 1.56 2.4 1.4 1.4 1 1 1 1.4 2 5 PCB-112 1.46 2.3 1.4 1.5 1 1 1 1.4 1 5 PCB-114 1.6 2.7 1.8 2.3 1 1.7 1 1.7 2 6 PCB-118 9.24 10.2 7.22 7.93 3.98 2.93 3.16 6.4 9 30 PCB-120 1.46 2.3 1.4 1.3 1 1 1 1.2 1 2 PCB-121 1.56 2.5 1.4 1.5 1 1 1 1.2 1 3 PCB-122 1.66 3 1.9 1.9 1 1.9 1 1.8 2 7 PCB-123 1.68 2.9 2 2 1 1.8 1 1.8 2 7 160 Congener Class Axys ID WG45312-101 L WG46585-101 L WG49873-101 WG54477-101 WG59905-101 WG63110-101 WG66480-101 Average (w/o outlier) LOD LOQ WORKGROUP WG45312 WG46585 WG49873 WG54477 WG59905 WG63110 WG66480 Sample Size 1sample 1sample 1sample 1sample 1sample 1sample 1sample UNITS pg pg pg pg pg pg pg pg pg pg PCB-126 1.8 2.8 2.2 2 1 1.8 1 1.8 2 6 PCB-127 1.48 2.8 1.9 1.7 1 1.8 1 1.7 2 6 Hexa PCB-128 + 166 2.4 2.79 2 1.9 1 1 1 1.7 2 7 PCB-129 + 138 + 160 + 163 12.96 17.1 10.4 8.94 3.88 2.13 6.78 8.9 16 52 PCB-130 3 1.8 2.4 2.3 1 1.1 1 1.8 2 8 PCB-131 2.8 1.7 2.1 2.3 1 1.1 1 1.7 2 7 PCB-132 3.2 3.26 2.3 3.1 1.08 1.1 1 2.1 3 11 PCB-133 2.8 1.6 2.1 2.1 1 1 1 1.7 2 7 PCB-134 + 143 2.8 1.7 2.1 2.3 1 1.1 1 1.7 2 7 PCB-135 + 151 + 154 4.48 3.65 1.9 1.7 1.58 1.24 1.98 2.4 4 12 PCB-136 1.68 1 1.4 1.56 1 1 1 1.2 1 3 PCB-137 2.8 1.6 2.2 2.1 1 1 1 1.7 2 7 PCB-139 + 140 2.6 1.5 1.9 2.1 1 1 1 1.6 2 6 PCB-141 2.6 1.56 2.35 2.63 1 1 1 1.7 2 8 PCB-142 2.8 1.7 2.2 2.3 1 1 1 1.7 2 7 PCB-144 2.2 1.2 2 1.8 1 1 1 1.5 2 5 PCB-145 1.72 1 1.5 1.5 1 1 1 1.2 1 3 PCB-146 2.6 2.97 3.03 1.9 1 1 1 1.9 3 9 PCB-147 + 149 4.18 5.64 10.5 7.97 3.4 1.97 2.25 5.1 9 31 PCB-148 2.2 1.2 2 1.8 1 1 1 1.5 2 5 PCB-150 1.62 1 1.4 1.4 1 1 1 1.2 1 3 PCB-152 1.64 1 1.3 1.3 1 1 1 1.2 1 2 PCB-153 + 168 4.64 21 18.1 10.5 3.13 1.89 3.29 8.9 23 78 PCB-155 1.2 1 1.7 1.1 1 1 1 1.1 1 3 161 Congener Class Axys ID WG45312-101 L WG46585-101 L WG49873-101 WG54477-101 WG59905-101 WG63110-101 WG66480-101 Average (w/o outlier) LOD LOQ WORKGROUP WG45312 WG46585 WG49873 WG54477 WG59905 WG63110 WG66480 Sample Size 1sample 1sample 1sample 1sample 1sample 1sample 1sample UNITS pg pg pg pg pg pg pg pg pg pg PCB-156 + 157 2.76 2.99 2.3 1.9 1 1.41 1 1.9 2 8 PCB-158 1.82 1.35 1.6 1.5 1 1 1 1.3 1 3 PCB-159 1.92 1.2 1.8 1.5 1 1 1 1.3 1 4 PCB-161 2 1.2 1.5 1.5 1 1 1 1.3 1 4 PCB-162 1.98 1.3 1.8 1.5 1 1 1 1.4 1 4 PCB-164 1.96 1.3 1.6 1.6 1 1 1 1.4 1 4 PCB-165 2.4 1.3 1.7 1.8 1 1 1 1.5 2 5 PCB-167 1.66 1.86 1.7 1.6 1 1 1 1.4 1 4 PCB-169 1.84 1.1 1.8 1.6 1 1 1 1.3 1 4 Hepta PCB-170 3.06 5.69 3.64 2.71 1 1 1 2.6 5 18 PCB-171 + 173 2.4 1.1 2.5 2 1 1 1 1.6 2 7 PCB-172 2.2 1.1 2.6 1.9 1 1 1 1.5 2 7 PCB-174 2.2 4.94 5.01 4.23 1 1 1.16 2.8 6 19 PCB-175 2.2 1 2.1 1.8 1 1 1 1.4 2 6 PCB-176 1.62 1 1.5 1.4 1 1 1 1.2 1 3 PCB-177 2.2 2 2.4 1.9 1 1 1 1.6 2 6 PCB-178 2.2 1 2.2 1.9 1 1 1 1.5 2 6 PCB-179 1.6 1 1.46 1.3 1 1 1 1.2 1 3 PCB-180 + 193 3.3 14.6 49.2 7.84 2.45 1 4.09 5.5 15 50 PCB-181 2.2 1 2.5 1.9 1 1 1 1.5 2 7 PCB-182 2 1 2.1 1.8 1 1 1 1.4 2 5 PCB-183 + 185 2.2 3.63 3.98 4.58 1 1 1 2.5 5 16 PCB-184 1.6 1 1.4 1.3 1 1 1 1.2 1 2 PCB-186 1.74 1 1.5 1.5 1 1 1 1.2 1 3 PCB-187 2.86 10.4 15.3 4.36 1.45 1 1.35 5.2 17 55 162 Congener Class Axys ID WG45312-101 L WG46585-101 L WG49873-101 WG54477-101 WG59905-101 WG63110-101 WG66480-101 Average (w/o outlier) LOD LOQ WORKGROUP WG45312 WG46585 WG49873 WG54477 WG59905 WG63110 WG66480 Sample Size 1sample 1sample 1sample 1sample 1sample 1sample 1sample UNITS pg pg pg pg pg pg pg pg pg pg PCB-188 1.44 1 1.7 1.4 1 1 1 1.2 1 3 PCB-189 1.86 1 2.4 1.6 1 1 1 1.4 2 6 PCB-190 1.66 1 2.1 1.5 1 1 1 1.3 1 4 PCB-191 1.64 1 2 1.4 1 1 1 1.3 1 4 PCB-192 1.84 1 2.2 1.6 1 1 1 1.4 2 5 Octa PCB-194 2.2 4.05 27.9 6.52 2.06 1 2.93 3.1 6 19 PCB-195 2.4 1.99 6.59 1.8 1 1 1 1.5 2 6 PCB-196 2.8 2.88 18.8 5.03 1 1 1.56 2.4 5 15 PCB-197 + 200 1.98 1.1 3.53 1.2 1 1 1 1.2 1 4 PCB-198 + 199 2.8 18.9 64.8 12.9 2.22 1.19 4.68 7.1 21 72 PCB-201 1.96 1.85 2.22 1.2 1 1 1 1.5 2 5 PCB-202 2.2 2.24 3.2 1.86 1 1 1 1.8 3 8 PCB-203 2.6 12.2 62.6 10.8 14 1 3.35 7.3 17 56 PCB-204 2 1.1 1.8 1.3 1 1 1 1.3 1 4 PCB-205 1.7 1 1.2 1.6 1 1 1 1.2 1 3 Nona PCB-206 3.4 5.51 27.4 11.4 3.21 3.1 5.35 5.3 9 32 PCB-207 2.6 2.06 4.88 2.53 1 2.1 1.8 2.0 2 6 PCB-208 2.6 4.58 13.9 5.14 1 2.3 2 2.9 5 16 Deca PCB-209 2.06 2.07 3.6 2.84 2.43 2.28 2.01 2.5 2 6 163 (b) Congener Class Axys ID WG45378-101 LW WG46128-101 W WG49872-101 K WG54476-101 WG63098-101 WG66478-101 Average (w/o outlier) LOD LOQ WORKGROUP WG45378 WG46128 WG49872 WG54476 WG63098 WG66478 Sample Size 1sample 1sample 1sample 1sample 1sample 1sample UNITS pg pg pg pg pg pg pg pg pg Mono PCB-1 19.2 13 2.68 5.54 1.74 0 7.0 23 75 PCB-2 19.2 12 3.29 2.34 0.664 0 6.2 23 77 PCB-3 21.6 9.9 5.02 75.9 4.1 0 19.4 86 287 Di PCB-4 96 3.87 2.6 5.35 2.28 5.1 3.8 4 14 PCB-5 76.8 2.2 1.8 1 1.3 4.2 2.1 4 13 PCB-6 64.8 1.9 1.6 1 1.63 3.8 2.0 3 11 PCB-7 65.6 2 1.6 866 1.1 3.8 14.8 85 284 PCB-8 57.6 1.8 1.79 8.37 6.31 6.76 5.0 9 30 PCB-9 67.2 2 1.6 1.51 1.1 3.7 2.0 3 10 PCB-10 65.6 1.9 1.5 1 1.2 3.8 1.9 3 11 PCB-11 68 19 8.16 33.6 26.5 8.08 27.2 67 224 PCB-12 + 13 68.8 2.3 1.7 1 1.2 3.8 2.0 3 11 PCB-14 68 2.1 1.6 1 1.1 3.8 1.9 3 11 PCB-15 104 2.76 1.9 6.35 2.85 4.5 3.7 5 18 Tri PCB-16 2.4 2.11 1.28 4.58 3.53 1.76 2.6 4 12 PCB-17 3.2 2.78 1.16 4.15 3.16 2.71 2.9 3 10 PCB-18 + 30 6.4 5.37 1.55 10.4 5.33 4.81 5.6 9 29 PCB-19 1.68 1.3 1 2.35 0.51 0.81 1.3 2 7 PCB-20 + 28 8 7.74 2.82 15.7 9.45 6.39 8.4 13 42 PCB-21 + 33 3.2 3.14 1.21 9.55 5.41 3.82 4.4 9 29 PCB-22 2.4 1.95 1 6.37 3.8 2.47 3.0 6 19 PCB-23 1.2 1 1 1 0.5 0.5 0.9 1 3 164 Congener Class Axys ID WG45378-101 LW WG46128-101 W WG49872-101 K WG54476-101 WG63098-101 WG66478-101 Average (w/o outlier) LOD LOQ WORKGROUP WG45378 WG46128 WG49872 WG54476 WG63098 WG66478 Sample Size 1sample 1sample 1sample 1sample 1sample 1sample UNITS pg pg pg pg pg pg pg pg pg PCB-24 1.36 1 1 1 0.5 0.5 0.9 1 3 PCB-25 0.96 1 1 1 0.717 0.582 0.9 1 2 PCB-26 + 29 1.6 1 1 4.13 1.34 1.19 1.2 1 3 PCB-27 1.28 1 1 1 0.635 0.5 0.9 1 3 PCB-31 5.6 5.13 1.97 12.3 7.53 5.49 6.3 10 34 PCB-32 2.4 2.01 1 3.37 2.33 1.4 2.1 2 8 PCB-34 1.28 1 1 1 0.5 0.5 0.9 1 3 PCB-35 1.36 1 1 1.14 0.5 0.5 0.9 1 3 PCB-36 1.2 1 1 1 0.5 0.5 0.9 1 3 PCB-37 1.6 1 1 2.35 2.42 2.21 1.8 2 7 PCB-38 1.28 1 1 1 0.5 0.5 0.9 1 3 PCB-39 1.2 1 1 1 0.5 0.5 0.9 1 3 Tetra PCB-40 + 41 + 71 3.2 2.61 1.21 5.76 3.17 2.18 3.0 5 15 PCB-42 1.76 1.4 1 2.39 1.27 0.668 1.4 2 6 PCB-43 2.16 1.7 1 1.4 0.5 0.5 1.2 2 7 PCB-44 + 47 + 65 8 7.12 3.45 11.3 9.77 7.22 7.8 8 27 PCB-45 + 51 2.4 1.4 1 2.91 2.28 1.57 1.9 2 7 PCB-46 2.16 1.6 1 1.3 0.5 0.5 1.2 2 6 PCB-48 1.84 1.4 1 2.68 1.41 0.5 1.5 2 7 PCB-49 + 69 3.2 2.36 1.28 4.58 3.02 2.44 2.8 3 11 PCB-50 + 53 1.84 1.4 1 1.63 0.902 0.5 1.2 2 5 PCB-52 8 6.21 12.2 11.4 5.32 3.68 7.8 10 34 PCB-54 1.12 1 1 1 0.5 0.5 0.9 1 3 PCB-55 1.68 1.4 1 1.5 0.5 0.5 1.1 2 5 PCB-56 1.76 1.4 1 1.86 2.4 0.541 1.5 2 7 165 Congener Class Axys ID WG45378-101 LW WG46128-101 W WG49872-101 K WG54476-101 WG63098-101 WG66478-101 Average (w/o outlier) LOD LOQ WORKGROUP WG45378 WG46128 WG49872 WG54476 WG63098 WG66478 Sample Size 1sample 1sample 1sample 1sample 1sample 1sample UNITS pg pg pg pg pg pg pg pg pg PCB-57 1.68 1.3 1 1.4 0.5 0.5 1.1 1 5 PCB-58 1.68 1.4 1 1.4 0.5 0.5 1.1 1 5 PCB-59 + 62 + 75 1.36 1.1 1 1 0.5 0.617 0.9 1 3 PCB-60 1.84 1.4 1 1.4 1.66 0.5 1.3 1 5 PCB-61 + 70 + 74 + 76 7.2 4.78 2.67 8.27 9.22 3.71 6.0 8 26 PCB-63 1.6 1.3 1 1.4 0.5 0.5 1.1 1 5 PCB-64 1.6 1.66 1 3.53 2.67 1.57 2.0 3 9 PCB-66 4 2.52 1 4.08 6 1.51 3.2 6 19 PCB-67 1.44 1.2 1 1.3 0.5 0.5 1.0 1 4 PCB-68 1.6 1.2 1 1.4 0.5 0.984 1.1 1 4 PCB-72 1.52 1.2 1 1.3 0.5 0.5 1.0 1 4 PCB-73 1.36 1 1 1 0.5 0.5 0.9 1 3 PCB-77 2.08 1.4 1 1.3 0.991 0.5 1.2 2 5 PCB-78 1.76 1.5 1 1.3 0.5 0.5 1.1 2 5 PCB-79 1.44 1.2 1 1.1 0.5 0.5 1.0 1 4 PCB-80 1.6 1.3 1 1.3 0.5 0.5 1.0 1 5 PCB-81 2 1.4 1 1.2 0.5 0.5 1.1 2 6 Penta PCB-82 2.96 1.9 1 1 0.513 0.5 1.3 3 10 PCB-83 + 99 2.8 1.6 3.14 2.95 12.7 2.14 2.5 2 6 PCB-84 3.12 1.9 1 1.5 1.5 0.5 1.6 3 9 PCB-85 + 116 + 117 2.4 1.4 1 1.04 1.53 0.5 1.3 2 6 PCB-86 + 87 + 97 + 108 + 119 + 125 4 2.83 1.61 3.17 5.26 2.1 3.2 4 13 PCB-88 + 91 2.56 1.6 1 1.51 0.598 0.5 1.3 2 8 166 Congener Class Axys ID WG45378-101 LW WG46128-101 W WG49872-101 K WG54476-101 WG63098-101 WG66478-101 Average (w/o outlier) LOD LOQ WORKGROUP WG45378 WG46128 WG49872 WG54476 WG63098 WG66478 Sample Size 1sample 1sample 1sample 1sample 1sample 1sample UNITS pg pg pg pg pg pg pg pg pg PCB-89 2.8 1.7 1 1 0.5 0.5 1.3 3 9 PCB-90 + 101 + 113 4.8 4.23 4.71 5.42 6.66 1.93 4.6 5 16 PCB-92 2.72 1.7 1 1 1.74 0.5 1.4 2 8 PCB-93 + 95 + 98 + 100 + 102 4.8 4.68 3.56 7.78 4.7 0.828 4.4 7 22 PCB-94 2.72 1.7 1 1 0.5 0.5 1.2 3 8 PCB-96 1.52 1.3 1 1 0.5 0.5 1.0 1 4 PCB-103 2.16 1.4 1 1 0.5 0.5 1.1 2 6 PCB-104 1.2 1.3 1 1 0.5 0.5 0.9 1 3 PCB-105 2.4 1.71 1.15 1.52 4.92 1.11 2.1 4 14 PCB-106 1.76 1.1 1 1 0.5 0.5 1.0 1 5 PCB-107 + 124 1.92 1.3 1 1 0.5 0.5 1.0 2 5 PCB-109 1.84 1.2 1 1 1.1 0.5 1.1 1 4 PCB-110 + 115 4.8 3.47 2.26 4.71 8.42 2.11 4.3 7 23 PCB-111 2 1.3 1 1 0.5 0.5 1.1 2 6 PCB-112 1.92 1.3 1 1 0.5 0.5 1.0 2 5 PCB-114 2.08 1.2 1 1 1.28 0.555 1.2 2 5 PCB-118 5.6 2.92 2.5 2.57 25 2.5 3.2 4 13 PCB-120 1.92 1.2 1 1 0.5 0.5 1.0 2 5 PCB-121 2 1.2 1 1 0.5 0.5 1.0 2 6 PCB-122 2.08 1.3 1 1 0.5 0.5 1.1 2 6 PCB-123 2.16 1.2 1 1 0.689 0.5 1.1 2 6 PCB-126 2.4 1.4 1 1 0.5 0.5 1.1 2 7 PCB-127 1.84 1.3 1 1 0.5 0.5 1.0 2 5 Hexa PCB-128 + 166 2.8 1.7 1 1 3.71 0.5 1.8 4 12 167 Congener Class Axys ID WG45378-101 LW WG46128-101 W WG49872-101 K WG54476-101 WG63098-101 WG66478-101 Average (w/o outlier) LOD LOQ WORKGROUP WG45378 WG46128 WG49872 WG54476 WG63098 WG66478 Sample Size 1sample 1sample 1sample 1sample 1sample 1sample UNITS pg pg pg pg pg pg pg pg pg PCB-129 + 138 + 160 + 163 8 3.88 4.51 4.11 38.3 1.7 4.4 7 23 PCB-130 3.6 2.1 1 1 1.36 0.5 1.6 3 11 PCB-131 3.44 1.9 1 1 0.58 0.5 1.4 3 11 PCB-132 3.76 2.08 1 1 1.98 0.5 1.7 4 12 PCB-133 3.44 1.9 1 1 1.36 0.5 1.5 3 10 PCB-134 + 143 3.36 5.29 1 1 0.56 0.5 2.0 6 19 PCB-135 + 151 + 154 2.8 2.1 1.16 1.87 4.43 0.901 2.2 4 13 PCB-136 2.16 1.6 1 1 0.726 0.5 1.2 2 6 PCB-137 3.44 2 1 1 1.51 0.5 1.6 3 10 PCB-139 + 140 2.96 1.7 1 1 0.5 0.5 1.3 3 9 PCB-141 3.12 1.8 1 1 0.5 0.523 1.3 3 10 PCB-142 3.36 1.9 1 1 0.56 0.5 1.4 3 11 PCB-144 2.88 2 1 1 0.5 0.5 1.3 3 9 PCB-145 2.16 1.6 1 1 0.5 0.5 1.1 2 6 PCB-146 2.96 1.6 1 1 12 0.5 1.4 3 9 PCB-147 + 149 3.04 18 3.37 3.37 7.48 1.35 6.1 19 62 PCB-148 2.88 2.1 1 1 0.5 0.5 1.3 3 10 PCB-150 2.08 1.6 1 1 0.5 0.5 1.1 2 6 PCB-152 2.08 1.5 1 1 0.5 0.5 1.1 2 6 PCB-153 + 168 2.56 4.3 7.32 3.19 80.3 3.48 4.2 6 19 PCB-155 1.36 1.4 1 1 0.5 0.5 1.0 1 4 PCB-156 + 157 2.8 1.8 1 1 5 0.5 2.0 5 17 PCB-158 2.16 1.3 1 1 3.15 0.5 1.5 3 10 PCB-159 2.32 1.4 1 1 0.5 0.5 1.1 2 7 168 Congener Class Axys ID WG45378-101 LW WG46128-101 W WG49872-101 K WG54476-101 WG63098-101 WG66478-101 Average (w/o outlier) LOD LOQ WORKGROUP WG45378 WG46128 WG49872 WG54476 WG63098 WG66478 Sample Size 1sample 1sample 1sample 1sample 1sample 1sample UNITS pg pg pg pg pg pg pg pg pg PCB-161 2.4 1.3 1 1 0.5 0.5 1.1 2 7 PCB-162 2.32 1.4 1 1 0.5 0.5 1.1 2 7 PCB-164 2.32 1.4 1 1 0.855 0.5 1.2 2 6 PCB-165 2.72 1.5 1 1 0.5 0.5 1.2 2 8 PCB-167 2 1.4 1 1 2.37 0.5 1.4 2 7 PCB-169 2.24 1.3 1 1 0.5 0.5 1.1 2 6 Hepta PCB-170 3.12 2 1 1 9.34 0.5 2.8 10 33 PCB-171 + 173 2.88 2.3 1 1 2.94 0.5 1.8 3 11 PCB-172 2.8 2.2 1 1 3.27 0.5 1.8 3 11 PCB-174 2.64 2 1 1 3.3 0.5 1.7 3 11 PCB-175 2.56 2 1 1 0.5 0.5 1.3 3 8 PCB-176 2 1.5 1 1 0.5 0.5 1.1 2 6 PCB-177 2.72 2.2 1 1 5.49 0.5 2.2 6 18 PCB-178 2.72 2.1 1 1 4.07 0.5 1.9 4 13 PCB-179 1.92 1.5 1 1 0.987 0.5 1.2 1 5 PCB-180 + 193 2.32 4.51 1.43 1 51.5 0.997 2.1 4 15 PCB-181 2.72 2.1 1 1 0.5 0.5 1.3 3 9 PCB-182 2.56 2 1 1 0.5 0.5 1.3 3 8 PCB-183 + 185 2.56 2 1 1 12.6 0.5 1.4 3 8 PCB-184 1.92 1.5 1 1 0.5 0.5 1.1 2 6 PCB-186 2.16 1.6 1 1 0.5 0.5 1.1 2 6 PCB-187 2.48 2.83 1.71 1 28.6 0.5 1.7 3 10 PCB-188 1.68 1.4 1 1 0.5 0.5 1.0 1 5 PCB-189 2.08 1.8 1 1 0.579 0.5 1.2 2 6 PCB-190 2 1.7 1 1 3.76 0.5 1.7 3 12 169 Congener Class Axys ID WG45378-101 LW WG46128-101 W WG49872-101 K WG54476-101 WG63098-101 WG66478-101 Average (w/o outlier) LOD LOQ WORKGROUP WG45378 WG46128 WG49872 WG54476 WG63098 WG66478 Sample Size 1sample 1sample 1sample 1sample 1sample 1sample UNITS pg pg pg pg pg pg pg pg pg PCB-191 2 1.7 1 1 0.5 0.5 1.1 2 6 PCB-192 2.24 1.9 1 1 0.5 0.5 1.2 2 7 Octa PCB-194 2.4 2.3 1 1 7.05 0.5 2.4 7 24 PCB-195 2.72 2.4 1 1 3.19 0.5 1.8 3 11 PCB-196 3.2 2.1 1 1 3.9 0.5 2.0 4 14 PCB-197 + 200 2.24 1.6 1 1 0.738 0.5 1.2 2 6 PCB-198 + 199 3.28 2.3 1 1 11.3 0.5 3.2 12 41 PCB-201 2.24 1.6 1 1 1.22 0.5 1.3 2 6 PCB-202 2.24 1.7 1 1 1.54 0.5 1.3 2 6 PCB-203 2.96 1.9 1 1 6.7 0.5 2.3 7 23 PCB-204 2.24 1.6 1 1 0.5 0.5 1.1 2 7 PCB-205 2.08 1.9 1 1 0.589 0.5 1.2 2 7 Nona PCB-206 3.84 2.5 1 1.4 3.37 1.8 2.3 3 11 PCB-207 2.88 2.2 1 1.1 0.78 1.2 1.5 2 8 PCB-208 2.88 2.5 1 1.1 1.21 1.4 1.7 2 8 Deca PCB-209 2 2.88 2.25 1.91 2.8 1.32 2.2 2 6 170 Table 4.2: (a) Laboratory procedural blanks for dissolved PCBs; (b) at sea procedural blank in 2017 for dissolved PCBs (silicon tubing vs. springs closing mechanisms of Niskin bottles); (c) laboratory procedural blank for particulate PCBs in 2013. The reported values have been corrected for laboratory analysis blanks of the corresponding sample batch (Table 4.1). Numbers in italics are above LoD but below LoQ. Bold numbers indicate values above LoQ. Empty cells indicate that blank-corrected values were below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K). (a) Congener Class Date LOQ 2013 May 2017 May 2017 Sample name XAD keg blank Blank-Silicon Tubing (IOS) Blank-Spring (IOS) UNITS pg pg pg pg Mono PCB-1 18 9 17 51 PCB-2 18 6 14 37 PCB-3 109 148 Di PCB-8 63 87 73 PCB-11 326 122 256 286 PCB-14 39 29 PCB-15 62 55 47 Tri PCB-16 23 14 36 29 PCB-17 27 14 34 23 PCB-18 + 30 89 31 53 50 PCB-19 9 5 4 PCB-20 + 28 80 44 119 92 PCB-21 + 33 49 25 77 58 PCB-22 28 17 49 38 PCB-25 3 1 21 6 PCB-26 + 29 10 6 20 16 PCB-27 5 4 3 PCB-31 67 37 99 78 PCB-32 15 9 20 16 PCB-35 6 3 4 PCB-37 11 6 16 12 Tetra PCB-40 + 41 + 71 21 17 20 16 PCB-42 9 7 9 8 PCB-44 + 47 + 65 43 211 822 72 PCB-45 + 51 9 37 113 12 PCB-46 6 3 2 PCB-48 7 7 8 8 PCB-49 + 69 17 20 33 16 PCB-50 + 53 3 5 4 4 171 Congener Class Date LOQ 2013 May 2017 May 2017 Sample name XAD keg blank Blank-Silicon Tubing (IOS) Blank-Spring (IOS) UNITS pg pg pg pg PCB-52 44 33 36 30 PCB-56 10 6 8 6 PCB-59 + 62 + 75 2 2 5 2 PCB-60 7 4 5 4 PCB-61 + 70 + 74 + 76 41 24 35 28 PCB-64 13 11 14 12 PCB-66 21 13 18 12 PCB-68 6 24 46 4 Penta PCB-83 + 99 17 6 6 PCB-84 8 4 PCB-86 + 87 + 97 + 108 + 119 + 125 26 9 8 PCB-88 + 91 7 2 PCB-90 + 101 + 113 28 12 19 12 PCB-92 8 4 PCB-93 + 95 + 98 + 100 + 102 27 10 19 13 PCB-110 + 115 29 15 9 Hexa PCB-132 11 4 PCB-135 + 151 + 154 12 8 PCB-136 3 2 3 1 PCB-147 + 149 31 11 Hepta PCB-179 3 1 Octa PCB-194 19 15 PCB-195 6 3 PCB-196 15 12 PCB-198 + 199 72 30 Nona PCB-206 32 28 PCB-207 6 4 9 PCB-208 16 9 Deca PCB-209 6 2 3 172 (b) Congener Class Date LOQ August 2018 Sample name Procedural Blank (VECTOR) UNITS pg pg Mono PCB-1 18 25 PCB-2 18 19 PCB-3 109 42 Di PCB-4 120 111 PCB-5 43 41 PCB-6 103 43 PCB-8 63 218 PCB-11 326 198 PCB-12 + 13 39 22 PCB-14 39 37 PCB-15 62 74 Tri PCB-16 23 61 PCB-17 27 50 PCB-18 + 30 89 105 PCB-19 9 17 PCB-20 + 28 80 135 PCB-21 + 33 49 82 PCB-22 28 53 PCB-24 4 2 PCB-25 3 9 PCB-26 + 29 10 22 PCB-27 5 6 PCB-31 67 115 PCB-32 15 35 PCB-35 6 5 PCB-37 11 26 Tetra PCB-40 + 41 + 71 21 28 PCB-42 9 15 PCB-44 + 47 + 65 43 102 PCB-45 + 51 9 20 PCB-46 6 4 PCB-48 7 13 PCB-49 + 69 17 31 PCB-50 + 53 3 8 PCB-52 44 114 PCB-56 10 17 PCB-59 + 62 + 75 2 4 PCB-60 7 8 PCB-61 + 70 + 74 + 76 41 79 PCB-64 13 24 173 Congener Class Date LOQ August 2018 Sample name Procedural Blank (VECTOR) UNITS pg pg PCB-66 21 29 PCB-68 6 12 PCB-77 4 3 Penta PCB-82 9 7 PCB-83 + 99 17 22 PCB-84 8 21 PCB-85 + 116 + 117 6 7 PCB-86 + 87 + 97 + 108 + 119 + 125 26 38 PCB-88 + 91 7 8 PCB-90 + 101 + 113 28 50 PCB-92 8 8 PCB-93 + 95 + 98 + 100 + 102 27 62 PCB-105 14 14 PCB-109 5 2 PCB-110 + 115 29 60 PCB-118 30 32 PCB-123 7 6 Hexa PCB-128 + 166 7 3 PCB-129 + 138 + 160 + 163 52 20 PCB-132 11 11 PCB-135 + 151 + 154 12 11 PCB-136 3 6 PCB-141 8 4 PCB-146 9 3 PCB-147 + 149 31 26 PCB-158 3 2 Hepta PCB-179 3 3 Deca PCB-209 6 2 (c) Congener Class Date LOD LOQ 2013 Sample name QMA pump blank UNITS pg pg pg Penta PCB-118 4 13 7 Hexa PCB-129 + 138 + 160 + 163 7 23 7 Nona PCB-208 2 8 7 174 Table 4.3: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PCB congeners in SoG seawater at Station S2. Quantifiable congeners are in bold. Detectable congeners below LoQ but above LoD are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K). (a) Congener Class Date LOQ 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth (m) 45-55 m 50 m 55-65 m Volume (L) 111.0 L 100.6 L 125.5 L UNITS pg pg pg pg Mono PCB-1 18 37 16 24 PCB-2 18 62 19 16 PCB-3 109 75 175 Di PCB-4 120 54 37 PCB-8 63 87 140 105 PCB-11 326 430 509 327 PCB-12 + 13 39 22 PCB-14 39 14 PCB-15 62 24 64 112 Tri PCB-16 23 45 74 172 PCB-17 27 40 61 111 PCB-18 + 30 89 100 129 211 PCB-19 9 16 22 16 PCB-20 + 28 80 114 293 521 PCB-21 + 33 49 83 198 381 PCB-22 28 45 141 286 PCB-24 4 2 PCB-25 3 10 19 41 PCB-26 + 29 10 20 43 75 PCB-27 5 6 9 17 PCB-31 67 96 240 422 PCB-32 15 24 37 77 PCB-35 6 7 17 32 PCB-36 5 2 PCB-37 11 22 76 171 PCB-39 5 10 Tetra PCB-40 + 41 + 71 21 46 123 287 PCB-42 9 22 46 127 PCB-43 5 7 15 PCB-44 + 47 + 65 43 2779 366 552 PCB-45 + 51 9 487 71 132 PCB-46 6 5 13 33 PCB-48 7 15 33 90 PCB-49 + 69 17 74 84 213 PCB-50 + 53 3 9 22 50 175 Congener Class Date LOQ 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth (m) 45-55 m 50 m 55-65 m Volume (L) 111.0 L 100.6 L 125.5 L UNITS pg pg pg pg PCB-52 44 114 304 612 PCB-55 3 1 3 4 PCB-56 10 29 101 179 PCB-57 2 1 0 PCB-58 3 1 PCB-59 + 62 + 75 2 8 18 35 PCB-60 7 14 48 100 PCB-61 + 70 + 74 + 76 41 114 375 656 PCB-63 3 1 5 11 PCB-64 13 33 85 186 PCB-66 21 47 148 264 PCB-67 1 1 3 9 PCB-68 6 455 86 62 PCB-72 2 1 PCB-77 4 5 22 32 PCB-79 2 1 3 3 PCB-80 3 1 Penta PCB-82 9 7 41 60 PCB-83 + 99 17 51 128 221 PCB-84 8 26 105 211 PCB-85 + 116 + 117 6 18 50 82 PCB-86 + 87 + 97 + 108 + 119 + 125 26 61 263 411 PCB-88 + 91 7 12 35 70 PCB-89 9 5 PCB-90 + 101 + 113 28 96 384 1118 PCB-92 8 14 60 149 PCB-93 + 95 + 98 + 100 + 102 27 95 398 1238 PCB-96 3 3 PCB-105 14 22 133 124 PCB-106 6 6 PCB-107 + 124 7 10 12 PCB-109 5 6 17 19 PCB-110 + 115 29 102 436 747 PCB-114 6 5 5 PCB-118 30 53 295 336 PCB-122 7 2 PCB-123 7 6 176 Congener Class Date LOQ 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth (m) 45-55 m 50 m 55-65 m Volume (L) 111.0 L 100.6 L 125.5 L UNITS pg pg pg pg Hexa PCB-128 + 166 7 9 51 52 PCB-129 + 138 + 160 + 163 52 54 391 566 PCB-130 8 3 18 22 PCB-131 7 5 8 PCB-132 11 22 149 320 PCB-133 7 3 7 PCB-134 + 143 7 4 25 46 PCB-135 + 151 + 154 12 33 148 688 PCB-136 3 11 66 301 PCB-137 7 4 10 13 PCB-139 + 140 6 5 4 3 PCB-141 8 15 90 176 PCB-144 5 5 21 102 PCB-146 9 8 43 91 PCB-147 + 149 31 66 373 1122 PCB-153 + 168 78 45 305 669 PCB-156 + 157 8 4 38 29 PCB-158 3 6 41 53 PCB-159 4 5 9 PCB-164 4 4 27 44 PCB-167 4 11 11 Hepta PCB-170 18 91 70 PCB-171 + 173 7 4 21 43 PCB-172 7 13 15 PCB-174 19 10 107 196 PCB-175 6 2 7 PCB-176 3 2 13 47 PCB-177 6 9 62 88 PCB-178 6 3 19 52 PCB-179 3 9 52 186 PCB-180 + 193 50 16 440 260 PCB-183 + 185 16 13 87 152 PCB-187 55 18 75 282 PCB-190 4 2 26 19 PCB-191 4 3 Octa PCB-194 19 336 145 PCB-195 6 99 47 PCB-196 15 165 127 PCB-197 + 200 4 1 9 32 177 Congener Class Date LOQ 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth (m) 45-55 m 50 m 55-65 m Volume (L) 111.0 L 100.6 L 125.5 L UNITS pg pg pg pg PCB-198 + 199 72 511 386 PCB-201 5 28 23 PCB-202 8 3 62 55 PCB-203 56 402 256 PCB-205 3 8 7 Nona PCB-206 32 206 289 PCB-207 6 55 66 PCB-208 16 93 139 Deca PCB-209 6 17 32 178 (b) Congener Class Date LOQ 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth (m) 55 m 48-52 m 55 m Volume (L) 561.8 L 711.3 L 163.1 L UNITS pg pg pg pg Mono PCB-2 77 34 76 Di PCB-4 14 5 14 PCB-6 11 9 PCB-8 30 37 PCB-12 + 13 11 6 PCB-14 11 6 PCB-15 18 6 32 16 Tri PCB-16 12 48 24 PCB-17 10 45 27 PCB-18 + 30 29 89 45 PCB-19 7 8 4 PCB-20 + 28 42 19 144 70 PCB-21 + 33 29 53 37 PCB-22 19 49 25 PCB-25 2 1 8 5 PCB-26 + 29 3 2 24 10 PCB-27 3 6 4 PCB-31 34 12 121 53 PCB-32 8 25 16 PCB-35 3 2 PCB-37 7 7 16 9 Tetra PCB-40 + 41 + 71 15 6 27 8 PCB-42 6 3 13 4 PCB-43 7 2 PCB-44 + 47 + 65 27 12 53 21 PCB-45 + 51 7 17 5 PCB-46 6 5 PCB-48 7 15 4 PCB-49 + 69 11 8 33 12 PCB-50 + 53 5 12 4 PCB-52 34 17 57 27 PCB-56 7 8 10 5 PCB-59 + 62 + 75 3 4 2 PCB-60 5 5 6 3 PCB-61 + 70 + 74 + 76 26 34 46 18 PCB-64 9 6 20 8 PCB-66 19 21 24 10 PCB-77 5 2 2 179 Congener Class Date LOQ 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth (m) 55 m 48-52 m 55 m Volume (L) 561.8 L 711.3 L 163.1 L UNITS pg pg pg pg Penta PCB-82 10 4 PCB-83 + 99 6 16 27 7 PCB-84 9 4 8 4 PCB-85 + 116 + 117 6 4 9 2 PCB-86 + 87 + 97 + 108 + 119 + 125 13 17 26 8 PCB-88 + 91 8 5 PCB-90 + 101 + 113 16 27 36 13 PCB-92 8 3 7 3 PCB-93 + 95 + 98 + 100 + 102 22 21 32 14 PCB-105 14 11 14 5 PCB-109 4 2 PCB-110 + 115 23 28 33 14 PCB-118 13 24 35 10 Hexa PCB-128 + 166 12 4 8 PCB-129 + 138 + 160 + 163 23 46 51 12 PCB-132 12 12 13 5 PCB-135 + 151 + 154 13 18 14 PCB-136 6 6 5 2 PCB-141 10 7 4 PCB-146 9 5 11 PCB-147 + 149 62 25 34 PCB-153 + 168 19 44 49 10 Hepta PCB-171 + 173 11 4 PCB-174 11 8 8 PCB-177 18 6 6 PCB-179 5 7 5 PCB-180 + 193 15 19 18 5 PCB-183 + 185 8 7 6 PCB-187 10 25 19 4 Octa PCB-202 6 2 2 Nona PCB-206 11 5 Deca PCB-209 6 7 3 180 Table 4.4: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PCB congeners concentrations (pg/L) in SoG seawater at Station S2. Quantifiable congeners are in bold. Detectable congeners below LoQ but above LoD are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K). (a) Congener Class Date 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth (m) 45-55 m 50 m 55-65 m Volume (L) 111.0 L 100.6 L 125.53 L UNITS pg/L pg/L pg/L Mono PCB-1 0.33 0.16 0.19 PCB-2 0.56 0.19 0.1 PCB-3 1 1.4 Di PCB-4 1 0.3 PCB-8 0.8 1.4 0.8 PCB-11 4 5 3 PCB-12 + 13 0.2 PCB-14 0.1 PCB-15 0.2 0.6 0.9 Tri PCB-16 0.4 0.7 1.4 PCB-17 0.4 0.6 0.9 PCB-18 + 30 0.9 1.3 1.7 PCB-19 0.14 0.22 0.13 PCB-20 + 28 1.0 2.9 4.2 PCB-21 + 33 0.7 2.0 3.0 PCB-22 0.4 1.4 2.3 PCB-24 0.02 PCB-25 0.09 0.19 0.32 PCB-26 + 29 0.18 0.42 0.60 PCB-27 0.05 0.08 0.14 PCB-31 0.9 2.4 3.4 PCB-32 0.21 0.37 0.62 PCB-35 0.06 0.17 0.26 PCB-36 0.02 PCB-37 0.20 0.75 1.36 PCB-39 0.09 Tetra PCB-40 + 41 + 71 0.4 1.2 2.29 PCB-42 0.19 0.46 1.01 PCB-43 0.07 0.12 PCB-44 + 47 + 65 25.0 3.6 4.4 PCB-45 + 51 4.39 0.71 1.05 PCB-46 0.04 0.13 0.26 PCB-48 0.13 0.32 0.72 181 Congener Class Date 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth (m) 45-55 m 50 m 55-65 m Volume (L) 111.0 L 100.6 L 125.53 L UNITS pg/L pg/L pg/L PCB-49 + 69 0.66 0.8 1.70 PCB-50 + 53 0.08 0.22 0.40 PCB-52 1.0 3.0 4.9 PCB-55 0.01 0.03 0.03 PCB-56 0.26 1.00 1.43 PCB-57 0.01 0.004 PCB-58 0.01 PCB-59 + 62 + 75 0.08 0.18 0.277 PCB-60 0.12 0.48 0.80 PCB-61 + 70 + 74 + 76 1.0 3.7 5.2 PCB-63 0.01 0.05 0.09 PCB-64 0.29 0.85 1.48 PCB-66 0.4 1.5 2.11 PCB-67 0.010 0.028 0.075 PCB-68 4.10 0.86 0.49 PCB-72 0.01 PCB-77 0.05 0.21 0.25 PCB-79 0.01 0.03 0.02 PCB-80 0.01 Penta PCB-82 0.1 0.41 0.48 PCB-83 + 99 0.46 1.3 1.76 PCB-84 0.23 1.04 1.68 PCB-85 + 116 + 117 0.16 0.50 0.65 PCB-86 + 87 + 97 + 108 + 119 + 125 0.6 2.6 3.3 PCB-88 + 91 0.11 0.34 0.56 PCB-89 0.04 PCB-90 + 101 + 113 0.9 3.8 8.9 PCB-92 0.13 0.60 1.19 PCB-93 + 95 + 98 + 100 + 102 0.9 4.0 9.9 PCB-96 0.02 PCB-105 0.20 1.33 0.99 PCB-106 0.1 PCB-107 + 124 0.10 0.10 PCB-109 0.05 0.17 0.15 PCB-110 + 115 0.9 4.3 5.9 PCB-114 0.1 0.04 PCB-118 0.5 2.9 2.7 182 Congener Class Date 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth (m) 45-55 m 50 m 55-65 m Volume (L) 111.0 L 100.6 L 125.53 L UNITS pg/L pg/L pg/L PCB-122 0.02 PCB-123 0.05 Hexa PCB-128 + 166 0.08 0.51 0.41 PCB-129 + 138 + 160 + 163 0.5 3.9 4.5 PCB-130 0.02 0.18 0.18 PCB-131 0.1 0.06 PCB-132 0.19 1.48 2.55 PCB-133 0.03 0.06 PCB-134 + 143 0.03 0.25 0.37 PCB-135 + 151 + 154 0.30 1.47 5.48 PCB-136 0.10 0.66 2.40 PCB-137 0.03 0.10 0.10 PCB-139 + 140 0.04 0.04 0.02 PCB-141 0.14 0.89 1.41 PCB-144 0.05 0.21 0.81 PCB-146 0.1 0.43 0.72 PCB-147 + 149 0.6 3.7 8.9 PCB-153 + 168 0.4 3.0 5.3 PCB-156 + 157 0.03 0.38 0.23 PCB-158 0.05 0.41 0.42 PCB-159 0.05 0.07 PCB-164 0.04 0.27 0.35 PCB-167 0.11 0.09 Hepta PCB-170 0.9 0.56 PCB-171 + 173 0.04 0.21 0.34 PCB-172 0.13 0.12 PCB-174 0.1 1.1 1.56 PCB-175 0.02 0.06 PCB-176 0.02 0.13 0.37 PCB-177 0.08 0.61 0.70 PCB-178 0.03 0.19 0.41 PCB-179 0.08 0.51 1.48 PCB-180 + 193 0.1 4.4 2.1 PCB-183 + 185 0.1 0.87 1.21 PCB-187 0.2 0.7 2.2 PCB-190 0.01 0.25 0.15 PCB-191 0.02 Octa PCB-194 3.3 1.16 PCB-195 0.99 0.38 183 Congener Class Date 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth (m) 45-55 m 50 m 55-65 m Volume (L) 111.0 L 100.6 L 125.53 L UNITS pg/L pg/L pg/L PCB-196 1.64 1.01 PCB-197 + 200 0.01 0.09 0.25 PCB-198 + 199 5.1 3.1 PCB-201 0.28 0.19 PCB-202 0.03 0.61 0.44 PCB-203 4.0 2.0 PCB-205 0.08 0.05 Nona PCB-206 2.0 2.3 PCB-207 0.54 0.53 PCB-208 0.93 1.11 Deca PCB-209 0.17 0.26 184 (b) Congener Class Date 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth (m) 55 m 48-52 m 55 m Volume (L) 561.8 L 711.3 L 163.1 L UNITS pg/L pg/L pg/L Mono PCB-2 0.1 0.1 Di PCB-4 0.01 0.09 PCB-6 0.05 PCB-8 0.23 PCB-12 + 13 0.01 PCB-14 0.01 PCB-15 0.01 0.05 0.1 Tri PCB-16 0.07 0.15 PCB-17 0.063 0.16 PCB-18 + 30 0.13 0.27 PCB-19 0.011 0.02 PCB-20 + 28 0.03 0.20 0.4 PCB-21 + 33 0.07 0.23 PCB-22 0.07 0.15 PCB-25 0.002 0.012 0.031 PCB-26 + 29 0.004 0.033 0.062 PCB-27 0.008 0.022 PCB-31 0.02 0.17 0.32 PCB-32 0.036 0.10 PCB-35 0.003 PCB-37 0.013 0.022 0.05 Tetra PCB-40 + 41 + 71 0.01 0.04 0.05 PCB-42 0.01 0.018 0.03 PCB-43 0.003 PCB-44 + 47 + 65 0.02 0.08 0.1 PCB-45 + 51 0.024 0.03 PCB-46 0.01 PCB-48 0.020 0.02 PCB-49 + 69 0.02 0.046 0.07 PCB-50 + 53 0.017 0.02 PCB-52 0.03 0.08 0.2 PCB-56 0.015 0.014 0.03 PCB-59 + 62 + 75 0.006 0.01 PCB-60 0.01 0.009 0.02 PCB-61 + 70 + 74 + 76 0.06 0.06 0.1 PCB-64 0.01 0.028 0.1 PCB-66 0.04 0.034 0.1 PCB-77 0.003 0.002 185 Congener Class Date 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth (m) 55 m 48-52 m 55 m Volume (L) 561.8 L 711.3 L 163.1 L UNITS pg/L pg/L pg/L Penta PCB-82 0.01 PCB-83 + 99 0.029 0.037 0.05 PCB-84 0.01 0.01 0.03 PCB-85 + 116 + 117 0.01 0.013 0.01 PCB-86 + 87 + 97 + 108 + 119 + 125 0.030 0.04 0.05 PCB-88 + 91 0.01 PCB-90 + 101 + 113 0.05 0.05 0.1 PCB-92 0.01 0.01 0.02 PCB-93 + 95 + 98 + 100 + 102 0.04 0.04 0.1 PCB-105 0.02 0.02 0.03 PCB-109 0.002 PCB-110 + 115 0.05 0.05 0.1 PCB-118 0.04 0.05 0.1 Hexa PCB-128 + 166 0.01 0.01 PCB-129 + 138 + 160 + 163 0.08 0.07 0.1 PCB-132 0.022 0.019 0.03 PCB-135 + 151 + 154 0.032 0.020 PCB-136 0.01 0.01 0.01 PCB-141 0.01 0.01 PCB-146 0.01 0.015 PCB-147 + 149 0.04 0.05 PCB-153 + 168 0.08 0.07 0.1 Hepta PCB-171 + 173 0.01 PCB-174 0.01 0.01 PCB-177 0.01 0.01 PCB-179 0.013 0.01 PCB-180 + 193 0.034 0.026 0.03 PCB-183 + 185 0.01 0.01 PCB-187 0.04 0.027 0.03 Octa PCB-202 0.004 0.003 Nona PCB-206 0.01 Deca PCB-209 0.012 0.004 186 Table 4.5: PCB concentrations in groups based on halogenation at Station S2. a) dissolved PCBs and b) particulate PCBs. Only quantifiable concentrations were included in the sum (Table 4.3). N/A means no congener is above LoQ. (a) Date 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Depth (m) 45-55 m 50 m 55-65 m Volume (L) 111.0 L 100.6 L 125.53 L UNITS pg/L pg/L pg/L Mono 0.9 0.19 1.6 Di 4.7 7.1 4.3 Tri 5.6 13.6 20.2 Tetra 38.3 19.5 29.1 Penta 5.0 23.4 38.2 Hexa 2.0 18.0 34.5 Hepta 0.2 10.0 11.3 Octa N/A 16.1 8.6 Nona N/A 3.5 3.9 Deca N/A 0.17 0.26 Total 56.6 111.6 152.0 (b) Date 11-Dec-2013 02-Oct-2014 15-Dec-2015 Station # Stn 2 Stn 2 Stn 2 Volume (L) 561.8 L 711.3 L 163.1 L Depth (m) 55 m 48-52 m 55 m UNITS pg/L pg/L pg/L Mono N/A N/A N/A Di N/A 0.05 0.32 Tri 0.013 0.89 2.0 Tetra 0.11 0.47 0.07 Penta 0.20 0.28 0.05 Hexa 0.21 0.20 N/A Hepta 0.09 0.05 N/A Octa N/A N/A N/A Nona N/A N/A N/A Deca 0.012 N/A N/A Total 0.64 1.94 2.42 187 Table 4.6: Detectable (>LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PCB congeners in SoG seawater at Station S4-1.5. Quantifiable congeners are in bold. Detectable congeners below LoQ but above LoD are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K). (a) Congener Class Date LOQ 10-Aug-2018 10-Aug-2018 10-Aug-2018 07-Aug-2018 07-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth (m) 4±2 m 26±2 m 54±2 m 70±2 m 147±2 m 294±2 m Volume (L) 120.9 L 124.5 L 122.7 L 123.5 L 83.0 L 122.8 L UNITS pg pg pg pg pg pg pg Mono PCB-1 18 29 50 23 22 508 66 PCB-2 18 37 57 28 19 520 72 PCB-3 109 36 113 1406 222 Di PCB-4 120 109 88 82 84 56 76 PCB-6 103 83 59 54 51 33 40 PCB-8 63 408 287 258 242 142 209 PCB-11 326 1044 588 512 1164 2174 572 PCB-12 + 13 39 23 23 17 18 29 24 PCB-14 39 43 22 42 44 52 35 PCB-15 62 144 104 91 140 80 103 Tri PCB-16 23 151 85 63 143 64 66 PCB-17 27 119 83 67 114 51 63 PCB-18 + 30 89 273 168 128 247 109 114 PCB-19 9 29 15 13 30 12 15 PCB-20 + 28 80 509 286 234 488 160 248 PCB-21 + 33 49 309 151 116 281 95 128 PCB-22 28 206 104 82 200 66 90 PCB-24 4 3 3 2 4 2 1 PCB-25 3 33 20 16 31 14 18 PCB-26 + 29 10 81 45 35 74 26 37 PCB-27 5 20 12 10 19 8 8 PCB-31 67 430 236 183 407 140 192 188 Congener Class Date LOQ 10-Aug-2018 10-Aug-2018 10-Aug-2018 07-Aug-2018 07-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth (m) 4±2 m 26±2 m 54±2 m 70±2 m 147±2 m 294±2 m Volume (L) 120.9 L 124.5 L 122.7 L 123.5 L 83.0 L 122.8 L UNITS pg pg pg pg pg pg pg PCB-32 15 104 57 45 96 35 46 PCB-35 6 17 9 8 17 19 11 PCB-36 5 1 PCB-37 11 97 42 34 107 36 43 Tetra PCB-40 + 41 + 71 21 107 47 42 113 40 47 PCB-42 9 51 23 17 53 20 21 PCB-43 5 6 2 6 2 PCB-44 + 47 + 65 43 14 91 PCB-45 + 51 9 22 23 PCB-46 6 16 7 4 15 5 5 PCB-48 7 39 21 17 46 15 16 PCB-49 + 69 17 89 35 26 101 21 30 PCB-50 + 53 3 23 10 7 28 8 8 PCB-52 44 282 148 121 344 123 144 PCB-55 3 3 1 2 1 PCB-56 10 69 32 27 82 29 33 PCB-57 2 2 1 1 PCB-58 3 2 PCB-59 + 62 + 75 2 19 8 7 18 7 8 PCB-60 7 38 18 14 50 13 18 PCB-61 + 70 + 74 + 76 41 262 122 102 301 108 127 PCB-63 3 5 2 2 6 1 1 PCB-64 13 77 37 34 100 33 35 PCB-66 21 123 51 43 132 38 53 PCB-67 1 4 2 1 4 1 1 PCB-72 2 2 1 PCB-77 4 11 6 4 13 5 7 189 Congener Class Date LOQ 10-Aug-2018 10-Aug-2018 10-Aug-2018 07-Aug-2018 07-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth (m) 4±2 m 26±2 m 54±2 m 70±2 m 147±2 m 294±2 m Volume (L) 120.9 L 124.5 L 122.7 L 123.5 L 83.0 L 122.8 L UNITS pg pg pg pg pg pg pg PCB-78 4 2 PCB-79 2 2 PCB-80 3 2 1 PCB-81 4 2 Penta PCB-82 9 12 7 6 16 6 8 PCB-83 + 99 17 55 32 27 64 25 34 PCB-84 8 42 23 20 57 21 26 PCB-85 + 116 + 117 6 15 11 10 21 8 13 PCB-86 + 87 + 97 + 108 + 119 + 125 26 84 53 44 102 47 60 PCB-88 + 91 7 17 10 10 23 9 10 PCB-90 + 101 + 113 28 145 76 61 176 62 75 PCB-92 8 21 13 9 29 11 15 PCB-93 + 95 + 98 + 100 + 102 27 168 90 68 227 69 84 PCB-96 3 1 PCB-105 14 21 17 13 31 17 20 PCB-107 + 124 7 2 PCB-109 5 3 2 5 2 PCB-110 + 115 29 123 74 65 156 67 86 PCB-118 30 56 40 35 67 39 49 PCB-122 7 5 PCB-123 7 14 17 17 6 8 14 Hexa PCB-128 + 166 7 5 5 4 5 3 6 PCB-129 + 138 + 160 + 163 52 39 27 26 40 25 34 PCB-132 11 23 13 12 28 15 17 190 Congener Class Date LOQ 10-Aug-2018 10-Aug-2018 10-Aug-2018 07-Aug-2018 07-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth (m) 4±2 m 26±2 m 54±2 m 70±2 m 147±2 m 294±2 m Volume (L) 120.9 L 124.5 L 122.7 L 123.5 L 83.0 L 122.8 L UNITS pg pg pg pg pg pg pg PCB-134 + 143 7 3 4 PCB-135 + 151 + 154 12 38 24 15 49 18 23 PCB-136 3 17 9 7 23 8 8 PCB-137 7 2 PCB-141 8 8 6 4 10 8 8 PCB-144 5 5 2 2 5 4 PCB-146 9 8 5 6 5 5 PCB-147 + 149 31 72 46 33 84 38 48 PCB-153 + 168 78 39 29 24 45 27 39 PCB-156 + 157 8 3 3 PCB-158 3 2 2 2 5 2 4 PCB-164 4 2 2 2 2 Hepta PCB-174 19 7 6 8 7 PCB-176 3 1 1 PCB-177 6 3 2 2 PCB-179 3 7 5 2 7 4 3 PCB-183 + 185 16 5 5 Nona PCB-207 6 4 191 (b) Congener Class Date LOQ 10-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Depth (m) 25 m 150 m Volume (L) 473.9 L 644.5 L UNITS pg pg pg Di PCB-8 30 15 PCB-11 224 77 PCB-15 18 8 Tri PCB-16 12 6 PCB-17 10 6 9 PCB-18 + 30 29 12 17 PCB-20 + 28 42 24 43 PCB-21 + 33 29 14 22 PCB-22 19 10 16 PCB-25 2 1 3 PCB-26 + 29 3 3 6 PCB-27 3 1 PCB-31 34 22 33 PCB-32 8 4 7 PCB-35 3 3 3 PCB-37 7 10 19 Tetra PCB-40 + 41 + 71 15 18 19 PCB-42 6 8 8 PCB-44 + 47 + 65 27 72 61 PCB-45 + 51 7 9 8 PCB-48 7 6 7 PCB-49 + 69 11 17 21 PCB-50 + 53 5 2 4 PCB-52 34 41 53 PCB-56 7 21 24 PCB-59 + 62 + 75 3 2 3 PCB-60 5 12 13 PCB-61 + 70 + 74 + 76 26 76 87 PCB-64 9 14 16 PCB-66 19 31 47 PCB-68 4 7 4 PCB-77 5 5 9 Penta PCB-82 10 11 9 PCB-83 + 99 6 48 48 PCB-84 9 23 18 192 Congener Class Date LOQ 10-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Depth (m) 25 m 150 m Volume (L) 473.9 L 644.5 L UNITS pg pg pg PCB-85 + 116 + 117 6 16 15 PCB-86 + 87 + 97 + 108 + 119 + 125 13 57 51 PCB-88 + 91 8 9 8 PCB-90 + 101 + 113 16 80 74 PCB-92 8 14 12 PCB-93 + 95 + 98 + 100 + 102 22 73 65 PCB-105 14 22 33 PCB-107 + 124 5 2 2 PCB-109 4 4 4 PCB-110 + 115 23 86 83 PCB-118 13 56 65 PCB-123 6 2 2 Hexa PCB-128 + 166 12 6 8 PCB-129 + 138 + 160 + 163 23 51 70 PCB-132 12 22 21 PCB-135 + 151 + 154 13 27 28 PCB-136 6 16 9 PCB-137 10 3 PCB-141 10 8 9 PCB-144 9 5 3 PCB-146 9 7 9 PCB-147 + 149 62 56 49 PCB-153 + 168 19 44 57 PCB-156 + 157 17 10 PCB-158 10 4 5 PCB-164 6 3 4 PCB-167 7 3 Hepta PCB-170 33 15 PCB-171 + 173 11 4 PCB-174 11 9 13 PCB-177 18 8 PCB-179 5 6 8 PCB-180 + 193 15 13 27 PCB-183 + 185 8 7 8 193 Congener Class Date LOQ 10-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Depth (m) 25 m 150 m Volume (L) 473.9 L 644.5 L UNITS pg pg pg PCB-187 10 14 26 PCB-189 6 3 Octa PCB-198 + 199 41 12 PCB-202 6 5 PCB-205 7 3 Nona PCB-206 11 8 PCB-208 8 3 Deca PCB-209 6 10 194 Table 4.7: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PCB congeners concentrations (pg/L) in SoG seawater at Station S4-1.5. Quantifiable congeners are in bold. Detectable congeners below LoQ but above LoD are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K). (a) Congener Class Date 10-Aug-2018 10-Aug-2018 10-Aug-2018 07-Aug-2018 07-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth (m) 4±2 m 26±2 m 54±2 m 70±2 m 147±2 m 294±2 m Volume (L) 120.9 L 124.5 L 122.7 L 123.5 L 83.0 L 122.8 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L Mono PCB-1 0.24 0.40 0.19 0.18 6.1 0.54 PCB-2 0.30 0.46 0.23 0.16 6.3 0.59 PCB-3 0.3 0.9 16.9 1.8 Di PCB-4 1 1 1 1 1 1 PCB-6 1 0.5 0.4 0.4 0.4 0.3 PCB-8 3.4 2.3 2.1 2.0 1.7 1.7 PCB-11 9 5 4 9 26 5 PCB-12 + 13 0.2 0.2 0.1 0.1 0.3 0.2 PCB-14 0.4 0.2 0.34 0.4 0.6 0.3 PCB-15 1.2 0.8 0.7 1.1 1.0 0.8 Tri PCB-16 1.3 0.7 0.5 1.2 0.8 0.5 PCB-17 1.0 0.7 0.5 0.9 0.6 0.5 PCB-18 + 30 2.3 1.4 1.0 2.0 1.3 0.9 PCB-19 0.24 0.12 0.11 0.24 0.15 0.12 PCB-20 + 28 4.2 2.3 1.9 4.0 1.9 2.0 PCB-21 + 33 2.6 1.2 0.9 2.3 1.1 1.0 PCB-22 1.7 0.8 0.7 1.6 0.8 0.7 PCB-24 0.02 0.02 0.01 0.03 0.02 0.01 PCB-25 0.27 0.16 0.13 0.25 0.17 0.15 195 Congener Class Date 10-Aug-2018 10-Aug-2018 10-Aug-2018 07-Aug-2018 07-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth (m) 4±2 m 26±2 m 54±2 m 70±2 m 147±2 m 294±2 m Volume (L) 120.9 L 124.5 L 122.7 L 123.5 L 83.0 L 122.8 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L PCB-26 + 29 0.67 0.36 0.29 0.60 0.32 0.30 PCB-27 0.16 0.09 0.08 0.15 0.10 0.07 PCB-31 3.6 1.9 1.5 3.3 1.7 1.6 PCB-32 0.86 0.46 0.36 0.77 0.42 0.37 PCB-35 0.14 0.07 0.06 0.14 0.23 0.09 PCB-37 0.81 0.34 0.28 0.87 0.43 0.35 Tetra PCB-40 + 41 + 71 0.9 0.38 0.3 0.92 0.5 0.4 PCB-42 0.42 0.18 0.14 0.43 0.24 0.17 PCB-43 0.05 0.01 0.05 0.02 PCB-44 + 47 + 65 0.1 0.7 PCB-45 + 51 0.18 0.19 PCB-46 0.13 0.05 0.03 0.12 0.1 0.04 PCB-48 0.33 0.17 0.13 0.37 0.18 0.13 PCB-49 + 69 0.74 0.28 0.21 0.82 0.3 0.24 PCB-50 + 53 0.19 0.08 0.05 0.23 0.09 0.06 PCB-52 2.3 1.2 1.0 2.8 1.5 1.2 PCB-55 0.02 0.01 0.02 0.01 PCB-56 0.57 0.25 0.22 0.66 0.35 0.27 PCB-57 0.018 0.01 0.01 PCB-58 0.02 PCB-59 + 62 + 75 0.15 0.06 0.05 0.15 0.08 0.06 PCB-60 0.32 0.15 0.11 0.41 0.15 0.15 PCB-61 + 70 + 74 + 76 2.2 1.0 0.8 2.4 1.3 1.0 196 Congener Class Date 10-Aug-2018 10-Aug-2018 10-Aug-2018 07-Aug-2018 07-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth (m) 4±2 m 26±2 m 54±2 m 70±2 m 147±2 m 294±2 m Volume (L) 120.9 L 124.5 L 122.7 L 123.5 L 83.0 L 122.8 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L PCB-63 0.04 0.01 0.02 0.05 0.01 0.01 PCB-64 0.63 0.29 0.28 0.81 0.40 0.28 PCB-66 1.0 0.41 0.4 1.07 0.5 0.4 PCB-67 0.030 0.012 0.007 0.034 0.007 0.010 PCB-72 0.02 0.01 PCB-77 0.09 0.05 0.04 0.10 0.06 0.05 PCB-78 0.02 PCB-79 0.01 PCB-80 0.02 0.01 PCB-81 0.02 Penta PCB-82 0.10 0.1 0.05 0.13 0.1 0.1 PCB-83 + 99 0.46 0.25 0.22 0.51 0.3 0.28 PCB-84 0.35 0.19 0.16 0.46 0.25 0.21 PCB-85 + 116 + 117 0.12 0.09 0.08 0.17 0.10 0.10 PCB-86 + 87 + 97 + 108 + 119 + 125 0.7 0.4 0.4 0.8 0.6 0.5 PCB-88 + 91 0.14 0.08 0.08 0.18 0.11 0.08 PCB-90 + 101 + 113 1.2 0.6 0.5 1.4 0.8 0.6 PCB-92 0.17 0.10 0.07 0.24 0.13 0.12 PCB-93 + 95 + 98 + 100 + 102 1.4 0.7 0.6 1.8 0.8 0.7 PCB-96 0.01 PCB-105 0.17 0.14 0.1 0.25 0.20 0.16 197 Congener Class Date 10-Aug-2018 10-Aug-2018 10-Aug-2018 07-Aug-2018 07-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth (m) 4±2 m 26±2 m 54±2 m 70±2 m 147±2 m 294±2 m Volume (L) 120.9 L 124.5 L 122.7 L 123.5 L 83.0 L 122.8 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L PCB-107 + 124 0.02 PCB-109 0.02 0.01 0.04 0.02 PCB-110 + 115 1.0 0.6 0.5 1.3 0.8 0.7 PCB-118 0.46 0.32 0.29 0.54 0.47 0.40 PCB-122 0.1 PCB-123 0.11 0.13 0.14 0.05 0.10 0.12 Hexa PCB-128 + 166 0.04 0.04 0.03 0.04 0.04 0.05 PCB-129 + 138 + 160 + 163 0.3 0.2 0.2 0.3 0.3 0.3 PCB-132 0.19 0.11 0.09 0.23 0.18 0.14 PCB-134 + 143 0.02 0.03 PCB-135 + 151 + 154 0.31 0.19 0.12 0.40 0.22 0.19 PCB-136 0.14 0.07 0.05 0.18 0.10 0.06 PCB-137 0.02 PCB-141 0.07 0.1 0.03 0.08 0.1 0.06 PCB-144 0.04 0.02 0.02 0.04 0.03 PCB-146 0.1 0.04 0.05 0.1 0.04 PCB-147 + 149 0.6 0.4 0.3 0.7 0.5 0.4 PCB-153 + 168 0.3 0.2 0.2 0.4 0.3 0.3 PCB-156 + 157 0.04 0.02 PCB-158 0.01 0.02 0.02 0.04 0.02 0.03 PCB-164 0.02 0.02 0.02 0.02 Hepta PCB-174 0.1 0.05 0.1 0.1 PCB-176 0.01 0.01 198 Congener Class Date 10-Aug-2018 10-Aug-2018 10-Aug-2018 07-Aug-2018 07-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth (m) 4±2 m 26±2 m 54±2 m 70±2 m 147±2 m 294±2 m Volume (L) 120.9 L 124.5 L 122.7 L 123.5 L 83.0 L 122.8 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L PCB-177 0.02 0.02 0.02 PCB-179 0.06 0.04 0.02 0.06 0.05 0.03 PCB-183 + 185 0.1 0.04 Nona PCB-207 0.03 199 (b) Congener Class Date 10-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Depth (m) 25 m 150 m Volume (L) 473.9 L 644.5 L UNITS pg/L pg/L Di PCB-8 0.03 PCB-11 0.2 PCB-15 0.02 Tri PCB-16 0.01 PCB-17 0.01 0.01 PCB-18 + 30 0.03 0.03 PCB-20 + 28 0.1 0.07 PCB-21 + 33 0.03 0.03 PCB-22 0.02 0.02 PCB-25 0.003 0.005 PCB-26 + 29 0.007 0.010 PCB-27 0.002 PCB-31 0.05 0.1 PCB-32 0.01 0.01 PCB-35 0.01 0.005 PCB-37 0.021 0.030 Tetra PCB-40 + 41 + 71 0.04 0.03 PCB-42 0.017 0.013 PCB-44 + 47 + 65 0.15 0.09 PCB-45 + 51 0.019 0.013 PCB-48 0.01 0.01 PCB-49 + 69 0.04 0.03 PCB-50 + 53 0.01 0.01 PCB-52 0.09 0.08 PCB-56 0.045 0.037 PCB-59 + 62 + 75 0.004 0.004 PCB-60 0.025 0.020 PCB-61 + 70 + 74 + 76 0.16 0.13 PCB-64 0.030 0.025 PCB-66 0.07 0.07 PCB-68 0.015 0.01 PCB-77 0.01 0.013 Penta PCB-82 0.02 0.01 PCB-83 + 99 0.102 0.075 200 Congener Class Date 10-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Depth (m) 25 m 150 m Volume (L) 473.9 L 644.5 L UNITS pg/L pg/L PCB-84 0.05 0.028 PCB-85 + 116 + 117 0.033 0.024 PCB-86 + 87 + 97 + 108 + 119 + 125 0.12 0.08 PCB-88 + 91 0.019 0.013 PCB-90 + 101 + 113 0.17 0.11 PCB-92 0.029 0.018 PCB-93 + 95 + 98 + 100 + 102 0.15 0.10 PCB-105 0.05 0.05 PCB-107 + 124 0.004 0.003 PCB-109 0.01 0.01 PCB-110 + 115 0.18 0.13 PCB-118 0.12 0.10 PCB-123 0.004 0.003 Hexa PCB-128 + 166 0.01 0.01 PCB-129 + 138 + 160 + 163 0.11 0.11 PCB-132 0.05 0.032 PCB-135 + 151 + 154 0.06 0.04 PCB-136 0.033 0.014 PCB-137 0.01 PCB-141 0.02 0.01 PCB-144 0.01 0.005 PCB-146 0.02 0.01 PCB-147 + 149 0.1 0.1 PCB-153 + 168 0.09 0.09 PCB-156 + 157 0.02 PCB-158 0.01 0.01 PCB-164 0.01 0.01 PCB-167 0.005 Hepta PCB-170 0.02 PCB-171 + 173 0.01 PCB-174 0.02 0.021 201 Congener Class Date 10-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Depth (m) 25 m 150 m Volume (L) 473.9 L 644.5 L UNITS pg/L pg/L PCB-177 0.01 PCB-179 0.014 0.013 PCB-180 + 193 0.03 0.04 PCB-183 + 185 0.02 0.01 PCB-187 0.03 0.040 PCB-189 0.004 Octa PCB-198 + 199 0.02 PCB-202 0.01 PCB-205 0.005 Nona PCB-206 0.01 PCB-208 0.01 Deca PCB-209 0.016 202 Table 4.8: PCB concentrations in groups based on the halogenation at S4-1.5. a) dissolved PCBs and b) particulate PCBs. Only quantifiable concentrations were included in the sum (Table 4.6). N/A means no congener is above LoQ. (a) Date 10-Aug-2018 10-Aug-2018 10-Aug-2018 07-Aug-2018 07-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Stn 4-1.5 Depth (m) 4±2 m 26±2 m 54±2 m 70±2 m 147±2 m 294±2 m Volume (L) 120.9 L 124.5 L 122.7 L 123.5 L 83.0 L 122.8 L UNITS pg/L pg/L pg/L pg/L pg/L pg/L Mono 0.5 1.8 0.4 0.34 29.3 2.9 Di 14 8 7 13 29 7 Tri 19.7 10.5 8.4 18.3 10.1 8.8 Tetra 10.3 4.5 3.8 12.4 5.5 4.5 Penta 6.4 3.7 3.0 7.8 4.6 4.0 Hexa 1.3 0.7 0.5 1.7 1.0 0.9 Hepta 0.06 0.04 N/A 0.06 0.05 0.03 Octa N/A N/A N/A N/A N/A N/A Nona N/A N/A N/A N/A N/A N/A Deca N/A N/A N/A N/A N/A N/A Total 51.81 29.15 23.47 53.39 80.04 28.26 (b) Date 10-Aug-2018 07-Aug-2018 Station # Stn 4-1.5 Stn 4-1.5 Volume (L) 473.9 L 644.5 L Depth (m) 25 m 150 m UNITS pg/L pg/L Mono N/A N/A Di N/A N/A Tri 0.03 0.11 Tetra 0.69 0.57 Penta 1.05 0.73 Hexa 0.34 0.29 Hepta 0.04 0.12 Octa N/A N/A Nona N/A N/A Deca N/A 0.02 Total 2.14 1.83 203 Table 4.9: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PCB congeners in SoG seawater at Stations S1, S3 and S3b. Quantifiable congeners are in bold. Detectable congeners below LoQ but above LoD are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K). (a) Congener Class Date LOQ 11-Dec-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 53-60 m 5-25 m 15-35 m 15-24 m Volume (L) 110.1 L 207.6 L 117.0 L 101.5 L UNITS pg pg pg pg pg Mono PCB-1 18 28 112 35 44 PCB-2 18 23 126 15 13 PCB-3 109 247 106 Di PCB-4 120 162 89 160 PCB-6 103 65 45 PCB-8 63 96 322 129 221 PCB-11 326 467 817 283 439 PCB-12 + 13 39 52 15 PCB-14 39 22 PCB-15 62 25 167 112 83 Tri PCB-16 23 55 312 155 109 PCB-17 27 50 269 132 100 PCB-18 + 30 89 113 476 246 201 PCB-19 9 19 60 29 45 PCB-20 + 28 80 131 881 529 265 PCB-21 + 33 49 80 596 316 143 PCB-22 28 51 367 238 103 PCB-23 5 3 PCB-24 4 8 2 3 PCB-25 3 9 89 52 24 PCB-26 + 29 10 22 145 93 50 PCB-27 5 7 38 24 19 PCB-31 67 111 701 406 209 PCB-32 15 30 152 88 63 PCB-34 5 3 PCB-35 6 9 28 23 16 PCB-36 5 2 2 PCB-37 11 23 222 147 64 204 Congener Class Date LOQ 11-Dec-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 53-60 m 5-25 m 15-35 m 15-24 m Volume (L) 110.1 L 207.6 L 117.0 L 101.5 L UNITS pg pg pg pg pg PCB-38 5 2 PCB-39 5 15 2 2 Tetra PCB-40 + 41 + 71 21 54 506 311 99 PCB-42 9 25 213 139 48 PCB-43 5 3 34 16 7 PCB-44 + 47 + 65 43 1019 2731 582 105 PCB-45 + 51 9 229 887 132 29 PCB-46 6 6 66 35 14 PCB-48 7 16 166 93 35 PCB-49 + 69 17 54 486 270 107 PCB-50 + 53 3 11 101 63 33 PCB-52 44 138 1211 681 314 PCB-54 2 2 1 2 2 PCB-55 3 3 5 PCB-56 10 31 277 194 58 PCB-57 2 3 5 PCB-58 3 3 5 PCB-59 + 62 + 75 2 8 84 42 17 PCB-60 7 14 161 100 30 PCB-61 + 70 + 74 + 76 41 113 1083 733 237 PCB-63 3 1 18 14 4 PCB-64 13 37 337 205 71 PCB-66 21 48 503 310 110 PCB-67 1 1 14 10 3 PCB-68 6 200 424 52 5 PCB-72 2 3 5 PCB-73 2 2 PCB-77 4 5 53 31 10 PCB-78 4 3 2 PCB-79 2 7 5 1 PCB-80 3 3 2 PCB-81 4 3 5 Penta PCB-82 9 6 136 67 17 PCB-83 + 99 17 49 519 279 94 205 Congener Class Date LOQ 11-Dec-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 53-60 m 5-25 m 15-35 m 15-24 m Volume (L) 110.1 L 207.6 L 117.0 L 101.5 L UNITS pg pg pg pg pg PCB-84 8 25 390 243 60 PCB-85 + 116 + 117 6 16 166 88 23 PCB-86 + 87 + 97 + 108 + 119 + 125 26 66 896 459 123 PCB-88 + 91 7 12 145 83 25 PCB-89 9 10 7 PCB-90 + 101 + 113 28 100 1961 1218 205 PCB-92 8 15 283 173 32 PCB-93 + 95 + 98 + 100 + 102 27 106 2106 1358 229 PCB-94 9 4 PCB-96 3 8 3 1 PCB-103 6 6 3 PCB-105 14 21 310 127 39 PCB-106 6 6 4 PCB-107 + 124 7 28 11 2 PCB-109 5 46 20 5 PCB-110 + 115 29 101 1463 839 192 PCB-114 6 13 6 PCB-118 30 52 746 349 102 PCB-120 2 1 PCB-121 3 1 PCB-122 7 4 PCB-123 7 14 4 PCB-126 6 4 PCB-127 6 4 Hexa PCB-128 + 166 7 8 168 33 22 PCB-129 + 138 + 160 + 163 52 49 1280 417 120 PCB-130 8 60 19 7 PCB-131 7 15 7 PCB-132 11 16 562 266 46 PCB-133 7 17 4 PCB-134 + 143 7 90 44 5 206 Congener Class Date LOQ 11-Dec-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 53-60 m 5-25 m 15-35 m 15-24 m Volume (L) 110.1 L 207.6 L 117.0 L 101.5 L UNITS pg pg pg pg pg PCB-135 + 151 + 154 12 31 940 622 74 PCB-136 3 12 422 293 31 PCB-137 7 35 5 3 PCB-139 + 140 6 15 2 PCB-141 8 11 323 129 27 PCB-144 5 4 128 85 10 PCB-146 9 6 193 76 18 PCB-147 + 149 31 63 1690 957 152 PCB-153 + 168 78 39 1222 527 126 PCB-155 3 1 PCB-156 + 157 8 3 94 19 10 PCB-158 3 6 132 41 11 PCB-159 4 15 2 4 PCB-164 4 5 92 36 9 PCB-167 4 34 7 4 PCB-169 4 4 Hepta PCB-170 18 253 22 59 PCB-171 + 173 7 4 104 15 15 PCB-172 7 57 5 16 PCB-174 19 11 405 82 114 PCB-175 6 17 2 2 PCB-176 3 2 61 22 6 PCB-177 6 8 198 35 42 PCB-178 6 3 91 22 16 PCB-179 3 6 239 93 21 PCB-180 + 193 50 22 961 65 753 PCB-182 5 2 PCB-183 + 185 16 14 301 64 82 PCB-187 55 17 559 125 204 PCB-189 6 7 PCB-190 4 68 6 24 PCB-191 4 13 3 Octa PCB-194 19 8 328 540 PCB-195 6 107 165 207 Congener Class Date LOQ 11-Dec-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 53-60 m 5-25 m 15-35 m 15-24 m Volume (L) 110.1 L 207.6 L 117.0 L 101.5 L UNITS pg pg pg pg pg PCB-196 15 11 272 510 PCB-197 + 200 4 5 61 4 120 PCB-198 + 199 72 787 1679 PCB-201 5 45 4 85 PCB-202 8 3 99 9 136 PCB-203 56 20 642 1279 PCB-205 3 14 1 21 Nona PCB-206 32 315 971 PCB-207 6 5 74 242 PCB-208 16 150 541 Deca PCB-209 6 2 35 2 85 208 (b) Congener Class Date LOQ 05-Oct-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 65 m 5-25 m 20-30 m 18-20 m Volume (L) 745 L 187.6 L 172.0 L 191.9 L UNITS pg pg pg pg pg Mono PCB-1 75 51 31 PCB-2 77 74 PCB-3 287 90 Di PCB-4 14 6 66 38 PCB-5 13 58 PCB-6 11 6 37 10 PCB-8 30 157 49 PCB-9 10 9 PCB-11 224 200 199 110 PCB-12 + 13 11 8 11 PCB-15 18 46 74 21 Tri PCB-16 12 23 11 84 18 PCB-17 10 36 16 109 25 PCB-18 + 30 29 58 27 178 42 PCB-19 7 6 4 17 7 PCB-20 + 28 42 214 153 297 94 PCB-21 + 33 29 99 55 129 28 PCB-22 19 62 39 84 21 PCB-23 3 2 PCB-24 3 3 PCB-25 2 13 8 24 7 PCB-26 + 29 3 37 16 51 14 PCB-27 3 4 1 14 3 PCB-31 34 162 88 209 55 PCB-32 8 21 13 60 14 PCB-34 3 3 PCB-35 3 12 13 5 2 PCB-36 3 3 PCB-37 7 87 54 59 17 PCB-39 3 1 Tetra PCB-40 + 41 + 71 15 82 42 80 34 PCB-42 6 36 21 41 18 PCB-43 7 6 4 2 PCB-44 + 47 + 65 27 163 78 175 74 209 Congener Class Date LOQ 05-Oct-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 65 m 5-25 m 20-30 m 18-20 m Volume (L) 745 L 187.6 L 172.0 L 191.9 L UNITS pg pg pg pg pg PCB-45 + 51 7 21 8 31 10 PCB-46 6 5 3 9 3 PCB-48 7 27 14 30 12 PCB-49 + 69 11 87 50 103 54 PCB-50 + 53 5 13 6 19 9 PCB-52 34 223 90 205 114 PCB-54 3 2 PCB-55 5 3 2 3 PCB-56 7 103 58 74 32 PCB-57 5 3 PCB-58 5 3 PCB-59 + 62 + 75 3 13 7 14 7 PCB-60 5 53 38 41 17 PCB-61 + 70 + 74 + 76 26 359 240 325 148 PCB-63 5 7 4 6 3 PCB-64 9 61 33 62 27 PCB-66 19 194 151 186 74 PCB-67 4 5 3 5 2 PCB-68 4 4 15 1 PCB-72 4 2 PCB-73 3 1 PCB-77 5 38 21 20 7 PCB-78 5 3 PCB-79 4 4 2 3 2 PCB-80 5 3 PCB-81 6 3 Penta PCB-82 10 36 21 41 20 PCB-83 + 99 6 182 120 210 127 PCB-84 9 72 36 95 44 PCB-85 + 116 + 117 6 51 33 61 34 PCB-86 + 87 + 97 + 108 + 119 + 125 13 197 118 226 124 PCB-88 + 91 8 32 19 47 26 PCB-90 + 101 + 113 16 298 185 425 217 PCB-92 8 48 30 72 39 210 Congener Class Date LOQ 05-Oct-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 65 m 5-25 m 20-30 m 18-20 m Volume (L) 745 L 187.6 L 172.0 L 191.9 L UNITS pg pg pg pg pg PCB-93 + 95 + 98 + 100 + 102 22 209 120 333 149 PCB-103 6 3 2 PCB-104 3 2 PCB-105 14 167 104 131 66 PCB-107 + 124 5 10 7 11 7 PCB-109 4 25 16 25 13 PCB-110 + 115 23 303 204 439 218 PCB-114 5 8 4 7 3 PCB-118 13 338 238 342 162 PCB-122 6 5 4 PCB-123 6 5 3 6 3 Hexa PCB-128 + 166 12 64 52 99 42 PCB-129 + 138 + 160 + 163 23 438 348 662 250 PCB-130 11 28 17 38 15 PCB-131 11 6 PCB-132 12 152 91 229 80 PCB-133 10 5 3 8 PCB-134 + 143 19 19 13 32 13 PCB-135 + 151 + 154 13 125 81 208 81 PCB-136 6 50 28 83 29 PCB-137 10 17 12 25 7 PCB-139 + 140 9 4 4 8 5 PCB-141 10 66 51 123 33 PCB-144 9 14 11 28 11 PCB-146 9 67 50 89 30 PCB-147 + 149 62 187 204 493 198 PCB-153 + 168 19 384 262 553 173 PCB-155 4 3 2 PCB-156 + 157 17 44 39 58 25 PCB-158 10 35 30 61 22 PCB-159 7 3 6 2 PCB-162 7 87 PCB-164 6 30 18 44 17 211 Congener Class Date LOQ 05-Oct-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 65 m 5-25 m 20-30 m 18-20 m Volume (L) 745 L 187.6 L 172.0 L 191.9 L UNITS pg pg pg pg pg PCB-167 7 14 12 21 8 Hepta PCB-170 33 174 93 134 43 PCB-171 + 173 11 16 26 50 16 PCB-172 11 10 13 25 7 PCB-174 11 79 65 171 55 PCB-175 8 6 PCB-176 6 12 7 26 7 PCB-177 18 36 52 96 30 PCB-178 13 16 15 38 12 PCB-179 5 42 29 84 25 PCB-180 + 193 15 138 190 307 79 PCB-183 + 185 8 38 53 125 30 PCB-184 6 10 PCB-187 10 91 64 235 56 PCB-189 6 6 3 5 PCB-190 12 9 14 15 6 PCB-191 6 3 4 Octa PCB-194 24 46 61 64 16 PCB-195 11 11 20 25 6 PCB-196 14 22 16 38 11 PCB-197 + 200 6 7 4 15 5 PCB-198 + 199 41 47 45 87 24 PCB-201 6 4 4 14 3 PCB-202 6 14 12 27 7 PCB-203 23 25 26 52 12 PCB-205 7 2 Nona PCB-206 11 19 29 32 12 PCB-207 8 3 PCB-208 8 8 10 12 4 Deca PCB-209 6 15 29 24 12 212 Table 4.10: Detectable (> LoD) and quantifiable (>LoQ) dissolved (a) and particulate (b) PCB congeners concentrations (pg/L) in SoG seawater at Stations S1, S3 and S3b. Quantifiable congeners are in bold. Detectable congeners below LoQ but above LoD are in italics. Empty cells indicate below LoD. Color code reflects the analytical flags provided by AXYS: green = not detected at reporting limit (<); blue = did not meet quantification criteria (K). (a) Congener Class Date 11-Dec-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 53-60 m 5-25 m 15-35 m 15-24 m Volume (L) 110.1 L 207.6 L 117.03 L 101.5 L UNITS pg/L pg/L pg/L pg/L Mono PCB-1 0.25 0.54 0.30 0.4 PCB-2 0.21 0.61 0.1 0.1 PCB-3 1.2 1 Di PCB-4 0.8 1 1.6 PCB-6 0.3 0.4 PCB-8 0.9 1.5 1.1 2.2 PCB-11 4 3.9 2 4 PCB-12 + 13 0.3 0.1 PCB-14 0.2 PCB-15 0.2 0.8 1.0 0.8 Tri PCB-16 0.5 1.50 1.3 1.1 PCB-17 0.5 1.30 1.1 1.0 PCB-18 + 30 1.0 2.3 2.1 2.0 PCB-19 0.17 0.29 0.25 0.44 PCB-20 + 28 1.2 4.2 4.5 2.6 PCB-21 + 33 0.7 2.9 2.7 1.4 PCB-22 0.5 1.77 2.0 1.0 PCB-23 0.01 PCB-24 0.04 0.02 0.03 PCB-25 0.08 0.431 0.44 0.23 PCB-26 + 29 0.20 0.70 0.80 0.49 PCB-27 0.06 0.18 0.20 0.18 PCB-31 1.0 3.4 3.5 2.1 PCB-32 0.27 0.73 0.76 0.62 PCB-34 0.01 PCB-35 0.08 0.13 0.20 0.15 PCB-36 0.02 0.01 PCB-37 0.20 1.07 1.26 0.63 PCB-38 0.01 213 Congener Class Date 11-Dec-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 53-60 m 5-25 m 15-35 m 15-24 m Volume (L) 110.1 L 207.6 L 117.03 L 101.5 L UNITS pg/L pg/L pg/L pg/L PCB-39 0.07 0.02 0.02 Tetra PCB-40 + 41 + 71 0.5 2.44 2.7 1.0 PCB-42 0.22 1.03 1.19 0.48 PCB-43 0.02 0.16 0.14 0.07 PCB-44 + 47 + 65 9.3 13.2 5.0 1.0 PCB-45 + 51 2.08 4.27 1.13 0.29 PCB-46 0.05 0.32 0.30 0.14 PCB-48 0.15 0.80 0.80 0.34 PCB-49 + 69 0.49 2.34 2.31 1.1 PCB-50 + 53 0.10 0.485 0.54 0.32 PCB-52 1.3 5.8 5.8 3.1 PCB-54 0.01 0.004 0.02 0.02 PCB-55 0.01 0.05 PCB-56 0.28 1.33 1.66 0.57 PCB-57 0.014 0.044 PCB-58 0.01 0.05 PCB-59 + 62 + 75 0.08 0.405 0.355 0.16 PCB-60 0.13 0.77 0.86 0.30 PCB-61 + 70 + 74 + 76 1.0 5.2 6.3 2.3 PCB-63 0.01 0.089 0.12 0.04 PCB-64 0.34 1.62 1.75 0.70 PCB-66 0.4 2.42 2.7 1.1 PCB-67 0.01 0.068 0.084 0.027 PCB-68 1.81 2.04 0.45 0.05 PCB-72 0.013 0.04 PCB-73 0.016 PCB-77 0.04 0.25 0.26 0.10 PCB-78 0.01 0.02 PCB-79 0.034 0.04 0.01 PCB-80 0.013 0.02 PCB-81 0.01 0.05 Penta PCB-82 0.1 0.65 0.57 0.17 PCB-83 + 99 0.45 2.50 2.39 0.92 PCB-84 0.22 1.88 2.08 0.59 PCB-85 + 116 + 117 0.14 0.80 0.75 0.22 214 Congener Class Date 11-Dec-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 53-60 m 5-25 m 15-35 m 15-24 m Volume (L) 110.1 L 207.6 L 117.03 L 101.5 L UNITS pg/L pg/L pg/L pg/L PCB-86 + 87 + 97 + 108 + 119 + 125 0.6 4.32 3.9 1.2 PCB-88 + 91 0.11 0.70 0.71 0.24 PCB-89 0.05 0.1 PCB-90 + 101 + 113 0.9 9.45 10.4 2.0 PCB-92 0.14 1.36 1.48 0.32 PCB-93 + 95 + 98 + 100 + 102 1.0 10.15 11.6 2.3 PCB-94 0.02 PCB-96 0.040 0.02 0.01 PCB-103 0.03 0.03 PCB-105 0.19 1.50 1.08 0.39 PCB-106 0.1 0.02 PCB-107 + 124 0.13 0.09 0.02 PCB-109 0.22 0.17 0.05 PCB-110 + 115 0.9 7.05 7.2 1.9 PCB-114 0.06 0.1 PCB-118 0.5 3.59 3.0 1.0 PCB-120 0.003 PCB-121 0.004 PCB-122 0.02 PCB-123 0.07 0.04 PCB-126 0.02 PCB-127 0.02 Hexa PCB-128 + 166 0.07 0.81 0.28 0.21 PCB-129 + 138 + 160 + 163 0.4 6.2 3.6 1.2 PCB-130 0.29 0.17 0.1 PCB-131 0.07 0.06 PCB-132 0.15 2.71 2.27 0.45 PCB-133 0.08 0.04 PCB-134 + 143 0.43 0.37 0.1 PCB-135 + 151 + 154 0.28 4.53 5.32 0.73 PCB-136 0.10 2.031 2.51 0.30 PCB-137 0.17 0.04 0.03 PCB-139 + 140 0.07 0.02 215 Congener Class Date 11-Dec-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 53-60 m 5-25 m 15-35 m 15-24 m Volume (L) 110.1 L 207.6 L 117.03 L 101.5 L UNITS pg/L pg/L pg/L pg/L PCB-141 0.10 1.55 1.11 0.26 PCB-144 0.03 0.62 0.73 0.09 PCB-146 0.1 0.93 0.65 0.18 PCB-147 + 149 0.6 8.14 8.2 1.5 PCB-153 + 168 0.4 5.9 4.5 1.2 PCB-155 0.01 PCB-156 + 157 0.02 0.45 0.17 0.10 PCB-158 0.06 0.638 0.35 0.11 PCB-159 0.07 0.02 0.04 PCB-164 0.04 0.44 0.30 0.09 PCB-167 0.16 0.06 0.04 PCB-169 0.04 Hepta PCB-170 1.22 0.19 0.6 PCB-171 + 173 0.03 0.50 0.13 0.15 PCB-172 0.27 0.05 0.16 PCB-174 0.1 1.95 0.70 1.1 PCB-175 0.08 0.02 0.02 PCB-176 0.02 0.295 0.19 0.06 PCB-177 0.07 0.95 0.30 0.41 PCB-178 0.02 0.44 0.19 0.15 PCB-179 0.05 1.149 0.79 0.21 PCB-180 + 193 0.2 4.6 0.6 7.4 PCB-182 0.01 PCB-183 + 185 0.1 1.45 0.55 0.81 PCB-187 0.2 2.7 1.1 2.0 PCB-189 0.03 PCB-190 0.33 0.05 0.23 PCB-191 0.06 0.03 Octa PCB-194 0.1 1.58 5.3 PCB-195 0.52 1.63 PCB-196 0.1 1.31 5.02 PCB-197 + 200 0.05 0.30 0.03 1.18 PCB-198 + 199 3.8 16.5 PCB-201 0.22 0.03 0.84 PCB-202 0.03 0.48 0.08 1.34 216 Congener Class Date 11-Dec-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 53-60 m 5-25 m 15-35 m 15-24 m Volume (L) 110.1 L 207.6 L 117.03 L 101.5 L UNITS pg/L pg/L pg/L pg/L PCB-203 0.2 3.1 12.6 PCB-205 0.068 0.01 0.20 Nona PCB-206 1.52 9.6 PCB-207 0.05 0.36 2.38 PCB-208 0.72 5.33 Deca PCB-209 0.02 0.17 0.02 0.84 217 (b) Congener Class Date 05-Oct-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 65 m 5-25 m 20-30 m 18-20 m Volume (L) 745 L 187.6 L 172.0 L 191.9 L UNITS pg/L pg/L pg/L pg/L Mono PCB-1 0.07 0.2 PCB-2 0.10 PCB-3 0.12 Di PCB-4 0.03 0.39 0.20 PCB-5 0.31 PCB-6 0.03 0.21 0.1 PCB-8 0.9 0.26 PCB-9 0.1 PCB-11 0.27 1 1 PCB-12 + 13 0.04 0.1 PCB-15 0.25 0.43 0.11 Tri PCB-16 0.03 0.1 0.49 0.09 PCB-17 0.05 0.08 0.63 0.13 PCB-18 + 30 0.08 0.1 1.03 0.22 PCB-19 0.01 0.0 0.10 0.04 PCB-20 + 28 0.29 0.8 1.7 0.5 PCB-21 + 33 0.13 0.29 0.75 0.1 PCB-22 0.08 0.21 0.49 0.11 PCB-23 0.01 PCB-24 0.02 PCB-25 0.02 0.041 0.142 0.036 PCB-26 + 29 0.05 0.084 0.296 0.074 PCB-27 0.01 0.01 0.078 0.017 PCB-31 0.22 0.5 1.2 0.29 PCB-32 0.03 0.07 0.35 0.07 PCB-34 0.02 PCB-35 0.02 0.07 0.028 0.01 PCB-36 0.004 PCB-37 0.12 0.29 0.35 0.09 PCB-39 0.002 Tetra PCB-40 + 41 + 71 0.11 0.22 0.46 0.18 PCB-42 0.05 0.11 0.24 0.09 PCB-43 0.01 0.03 0.01 PCB-44 + 47 + 65 0.22 0.42 1.02 0.38 218 Congener Class Date 05-Oct-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 65 m 5-25 m 20-30 m 18-20 m Volume (L) 745 L 187.6 L 172.0 L 191.9 L UNITS pg/L pg/L pg/L pg/L PCB-45 + 51 0.03 0.04 0.18 0.05 PCB-46 0.01 0.01 0.05 0.02 PCB-48 0.04 0.07 0.17 0.06 PCB-49 + 69 0.12 0.27 0.60 0.28 PCB-50 + 53 0.02 0.03 0.11 0.05 PCB-52 0.30 0.5 1.2 0.6 PCB-54 0.01 PCB-55 0.004 0.01 0.01 PCB-56 0.14 0.31 0.43 0.16 PCB-57 0.004 PCB-58 0.004 PCB-59 + 62 + 75 0.02 0.04 0.08 0.035 PCB-60 0.07 0.20 0.24 0.09 PCB-61 + 70 + 74 + 76 0.48 1.28 1.89 0.77 PCB-63 0.01 0.02 0.04 0.02 PCB-64 0.08 0.17 0.36 0.14 PCB-66 0.26 0.80 1.08 0.39 PCB-67 0.01 0.01 0.027 0.01 PCB-68 0.01 0.09 0.01 PCB-72 0.003 PCB-73 0.001 PCB-77 0.05 0.11 0.11 0.04 PCB-78 0.004 PCB-79 0.01 0.01 0.01 0.01 PCB-80 0.003 PCB-81 0.004 Penta PCB-82 0.05 0.11 0.24 0.11 PCB-83 + 99 0.24 0.64 1.22 0.66 PCB-84 0.10 0.19 0.55 0.23 PCB-85 + 116 + 117 0.07 0.18 0.36 0.18 PCB-86 + 87 + 97 + 108 + 119 + 125 0.26 0.63 1.31 0.64 PCB-88 + 91 0.04 0.10 0.27 0.14 PCB-90 + 101 + 113 0.40 0.99 2.47 1.13 219 Congener Class Date 05-Oct-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 65 m 5-25 m 20-30 m 18-20 m Volume (L) 745 L 187.6 L 172.0 L 191.9 L UNITS pg/L pg/L pg/L pg/L PCB-92 0.06 0.16 0.42 0.20 PCB-93 + 95 + 98 + 100 + 102 0.28 0.64 1.94 0.78 PCB-103 0.02 0.01 PCB-104 0.01 PCB-105 0.22 0.55 0.76 0.34 PCB-107 + 124 0.01 0.04 0.06 0.04 PCB-109 0.03 0.09 0.14 0.07 PCB-110 + 115 0.41 1.09 2.55 1.13 PCB-114 0.01 0.02 0.04 0.01 PCB-118 0.45 1.27 1.99 0.84 PCB-122 0.01 0.02 PCB-123 0.01 0.02 0.03 0.02 Hexa PCB-128 + 166 0.09 0.28 0.58 0.22 PCB-129 + 138 + 160 + 163 0.59 1.86 3.85 1.30 PCB-130 0.04 0.09 0.22 0.08 PCB-131 0.04 PCB-132 0.20 0.48 1.33 0.41 PCB-133 0.01 0.02 0.04 PCB-134 + 143 0.03 0.1 0.18 0.1 PCB-135 + 151 + 154 0.17 0.43 1.21 0.42 PCB-136 0.07 0.15 0.48 0.15 PCB-137 0.02 0.06 0.15 0.04 PCB-139 + 140 0.01 0.02 0.04 0.02 PCB-141 0.09 0.27 0.72 0.17 PCB-144 0.02 0.06 0.16 0.05 PCB-146 0.09 0.27 0.52 0.16 PCB-147 + 149 0.25 1.1 2.9 1.0 PCB-153 + 168 0.52 1.39 3.21 0.90 PCB-155 0.005 0.01 PCB-156 + 157 0.06 0.21 0.34 0.13 PCB-158 0.05 0.16 0.36 0.11 PCB-159 0.02 0.04 0.01 PCB-162 0.12 220 Congener Class Date 05-Oct-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 65 m 5-25 m 20-30 m 18-20 m Volume (L) 745 L 187.6 L 172.0 L 191.9 L UNITS pg/L pg/L pg/L pg/L PCB-164 0.04 0.09 0.25 0.09 PCB-167 0.02 0.07 0.12 0.04 Hepta PCB-170 0.23 0.5 0.8 0.2 PCB-171 + 173 0.02 0.14 0.29 0.08 PCB-172 0.01 0.07 0.15 0.03 PCB-174 0.11 0.35 0.99 0.29 PCB-175 0.04 PCB-176 0.02 0.04 0.15 0.04 PCB-177 0.05 0.27 0.56 0.16 PCB-178 0.02 0.08 0.22 0.1 PCB-179 0.06 0.15 0.49 0.13 PCB-180 + 193 0.18 1.01 1.78 0.41 PCB-183 + 185 0.05 0.28 0.73 0.16 PCB-184 0.01 PCB-187 0.12 0.34 1.37 0.29 PCB-189 0.01 0.01 0.03 PCB-190 0.01 0.08 0.09 0.03 PCB-191 0.01 0.03 Octa PCB-194 0.06 0.32 0.37 0.1 PCB-195 0.01 0.11 0.15 0.03 PCB-196 0.03 0.09 0.22 0.1 PCB-197 + 200 0.01 0.02 0.09 0.02 PCB-198 + 199 0.06 0.24 0.5 0.1 PCB-201 0.01 0.02 0.08 0.02 PCB-202 0.02 0.07 0.15 0.03 PCB-203 0.03 0.14 0.30 0.1 PCB-205 0.01 Nona PCB-206 0.02 0.15 0.19 0.06 PCB-207 0.02 PCB-208 0.01 0.05 0.07 0.02 Deca PCB-209 0.02 0.15 0.14 0.06 221 Table 4.11: Dissolved (a) and particulate (b) PCB concentrations in groups based on the halogenation at S1 in December 2013, at S3 in December 2014 and at S3b in December 2015 and August 2016. Only quantifiable concentrations were included in the sum (Table 4.9). N/A means no congener is above LoQ. (a) Date 11-Dec-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 53-60 m 5-25 m 15-35 m 15-24 m Volume (L) 110.1 L 207.6 L 117.0 L 101.5 L UNITS pg/L pg/L pg/L pg/L Mono 0.5 2.3 0.30 0.4 Di 5.1 7.3 2.1 8.9 Tri 6.4 21.0 21.2 13.9 Tetra 18.2 45.1 34.6 13.1 Penta 5.1 44.5 45.4 11.2 Hexa 1.4 36.2 30.6 6.6 Hepta 0.13 16.1 4.7 13.3 Octa 0.05 11.4 0.08 44.7 Nona N/A 2.6 N/A 17.3 Deca N/A 0.17 N/A 0.84 Total 36.9 186.7 138.9 130.2 (b) Date 5-Oct-2013 05-Dec-2014 16-Dec-2015 31-Aug-2016 Station # Stn 1 Stn 3 Stn 3b Stn 3b Depth (m) 65 m 5-25 m 20-30 m 18-20 m Volume (L) 745 L 187.6 L 172.0 L 191.9 L UNITS pg/L pg/L pg/L pg/L Mono N/A N/A N/A N/A Di N/A 0.55 1.9 0.6 Tri 1.1 2.4 7.7 1.7 Tetra 2.0 4.6 8.4 3.3 Penta 2.7 6.7 14.3 6.5 Hexa 2.4 7.0 16.5 5.3 Hepta 0.88 3.3 7.6 1.8 Octa 0.22 1.0 1.9 0.03 Nona 0.02 0.20 0.26 0.06 Deca 0.02 0.15 0.14 0.06 Total 9.3 25.8 58.7 19.3 222 Table 4.12: Total dissolved concentrations, particulate concentration and %particulate of PBDE and PCB, and particulate and dissolved PCB/PBDE ratios in the Iona plume (S1), Burrard Inlet (S3, S3b), near the entrance of Burrard Inlet (S2), and in the middle of the southern SoG (S4-1.5). Items Unit S1 S3 S3b (2015) S3b (2016) S2 (2013) S2 (2014) S2 (2015) S4-1.5 (25 m) S4-1.5 (150 m) Total [PBDEs]diss (>LoQ) pg/L 275 381 73 54 266 251 266 363 292 Total [PBDEs]diss (>LoD) pg/L 330 382 74 55 303 385 375 364 292 Total [PBDEs]part (>LoQ) pg/L 189 29 124 0 97 0.6 0 0.5 0.6 Total [PBDEs]part (>LoD) pg/L 190 35 130 8 97 0.7 2.9 3.2 3.6 Total [PCBs]diss (>LoQ) pg/L 37 187 139 130 57 112 152 29 80 Total [PCBs]diss (>LoD) pg/L 39 187 144 131 59 113 153 32 83 Total [PCBs]part (>LoQ) pg/L 9 26 59 19 0.64 1.9 2.4 2.1 1.8 Total [PCBs]part (>LoD) pg/L 10 28 60 20 1.1 2.3 4.0 2.9 2.3 %particulate PBDEs (>LoQ) % 41 7 63 0 27 0.2 0 0.1 0.2 %particulate PBDEs (>LoD) % 37 8 64 13 24 0.2 0.8 0.9 1.2 %particulate PCBs (>LoQ) % 20 12 30 13 1.1 1.7 1.6 6.8 2.2 %particulate PCBs (>LoD) % 20 13 29 13 1.8 2.0 2.5 8.3 2.7 Particulate PCBs/PBDEs (>LoQ) 0.05 0.90 0.48 high 0.01 3.2 high 4.2 3.0 Particulate PCBs/PBDEs (>LoD) 0.05 0.80 0.46 2.5 0.01 3.3 1.4 0.9 0.6 Dissolved PCBs/PBDEs (>LoQ) 0.1 0.5 1.9 2.4 0.2 0.4 0.6 0.1 0.3 Dissolved PCBs/PBDEs (>LoD) 0.1 0.5 1.9 2.4 0.2 0.3 0.4 0.1 0.3 Table 4.13: Particulate congener ratios in S2 (Bowen Island), S3 (Inner Harbor in the Burrard Inlet) and S3b (Central Harbor in the Burrard Inlet). Data in Table 4.5b and Table 4.11b. Date 11-Dec-2013 01-Oct-2014 16-Dec-2015 05-Dec-2014 17-Dec-2015 31-Aug-2016 10-Aug-2018 07-Aug-2018 Station # Stn 2 Stn 2 Stn 2 Stn 3 Stn 3b Stn 3b Stn 4-1.5 (25 m) Stn 4-1.5 (150 m) Tri/Penta 0.1 3.2 43.3 0.4 0.5 0.3 0.0 0.2 Tri/Hexa 0.1 4.6 N/A 0.3 0.5 0.3 0.1 0.4 223 Table 4.14: Dissolved congener ratios in S2 (Bowen Island), S3 (Inner Harbor in the Burrard Inlet) and S3b(Central Harbor in the Burrard Inlet). Data in Table 4.5a and Table 4.11a. Date 11-Dec-2013 1-Oct-2014 16-Dec-2015 5-Dec-2014 17-Dec-2015 31-Aug-2016 10-Aug-2018 10-Aug-2018 10-Aug-2018 07-Aug-2018 07-Aug-2018 07-Aug-2018 Station Stn 2 Stn 2 Stn 2 Stn 3 Stn 3b Stn 3b Stn 4-1.5 (4±2 m) Stn 4-1.5 (26±2 m) Stn 4-1.5 (54±2) Stn 4-1.5 (70±2) Stn 4-1.5 (147±2) Stn 4-1.5 (294±2) Tri/Penta 1.1 0.6 0.5 0.5 0.5 1.2 3.1 2.9 2.8 2.3 2.2 2.2 Tri/Hexa 2.9 0.8 0.6 0.6 0.7 2.1 15.0 14.3 15.6 11.0 10.4 9.9 Table 4.15: Total PCB concentrations from the box model under two different scenarios. Experiment 1 added Victoria’s and Vancouver’s effluent input of 2003 reported by Dinn et al. (2012b) to the lower HS and lower SoG boxes, while the Experiment 2 had the same input as Experiment 1 with another 50 g/d of input was added to the upper SoG box. Location Experiment 1 Experiment 2 Measured (>LOQ) Reference of measured concentrations pg/L pg/L pg/L pg/L Upper SoG 2.3 34.7 34.8 This study Lower SoG 2.4 23.1 53.9 This study Upper HS 1.5 22.8 27.8-38.6 Frouin et al. (2013) Lower HS 0.98 14.0 25.2-34.4 Frouin et al. (2013) Upper JdF 1.1 16.1 N/A N/A Lower JdF 0.45 6.7 N/A N/A 224 Chapter 5: Conclusions 5.1 Summary of major findings Many studies have investigated PBDEs and PCBs in the Salish Sea focusing on their accumulation in sediment, benthic invertebrates and mammals. For example, sediment core profiles have showed that PCBs accumulation has decreased in the last decades, given that PCBs were banned more than 50 years ago. In contrast, PBDEs accumulation has been increasing (Johannessen et al., 2008a; Johannessen et al., 2008b), but is expected to plateau as their use is diminishing. Other studies have determined that PBDEs concentrations in sediments are directly related to the distance from major point sources, such as Iona WWTP and Vancouver Harbor (Grant et al., 2011; Johannessen et al., 2008b), and that BDE-209, 99, 47 and 100 congeners account for 80% of PBDEs in SoG sediments. In contrast, PCBs in SoG do not have clear point sources, although their distribution still point to historical sources from urban and industrialized areas (Grant et al., 2011). Furthermore, in SoG sediments, there is no single PBDE congener contributing more than 10% to the total, and most contribute less than 5% (Dinn et al., 2012a). In addition to these measurements in sediments and biota, determining the concentrations of PBDEs and PCBs in seawater is essential to establish the fraction of, and the processes whereby, PBDEs and PCBs discharged in the SoG are removed into the underlying sediments, accumulating in the food chain, or exported to the Pacific Ocean. This is, however, a challenging task, in part because of the large sample volumes required and the cost of analysis (~$1000 per sample). In this study, we have attempted to fill this knowledge gap by measuring dissolved (< 2.2 μm) and particulate (> 2.2 μm) PCBs and PBDEs concentration in seawater at various stations in the Salish Sea from 2013 to 2018. This thesis focuses mostly on PBDEs, whose concentrations in the environment are expected to overtake PCBs concentrations. Our major findings are described below. 5.1.1 PBDEs PBDEs are a class of hydrophobic and lipophilic brominated organic molecules whose tendency to associate with particles and organic matter in seawater varies with their level of 225 bromination. These physicochemical properties ultimately determine the tendency of a specific PBDEs congener in seawater to remain associated with contaminated particles discharged into the SoG or to desorb from these particles and enter the dissolved phase. Once in the dissolved phase, these PBDEs can a) be exported to the Pacific Ocean with the currents, b) be re-adsorbed on the surface of uncontaminated sinking marine particles (phytoplankton, marine snow, etc.) and removed to the sediment, or c) be internalized by marine organisms, thereby entering the marine food web. Our findings point to the Iona plume as a significant source of particulate PBDEs (pPBDEs) into the SoG, exhibiting concentrations 2 orders of magnitude higher than in the southern (S4-1.5) and northern (NG) SoG waters. This is consistent with the conclusions derived by Johannessen et al. (2008b) and Grant et al. (2011) based on the distribution of PBDEs in the SoG sediment. An earlier study (Dinn et al., 2012a) had also shown that only 10% of the PDBE discharged by WWTP outfalls accumulate in proximal sediments, and suggested that 90% of the PBDE-enriched sewage particles are fragmented and dispersed in the SoG as fine particles that slowly sink farther away from the point of discharge. However, our data show that most of the PBDEs measured in SoG water are “dissolved” (i.e. smaller than 2.2 μm). Furthermore, dissolved PBDEs (dPBDEs) are not directly discharged from the Iona outfall since the concentrations of dissolved PBDEs within the Iona plume (S1) are similar to the dPBDEs concentrations measured within the plume dispersion zone (S2), in Burrard Inlet (S3), and at the centrally located SoG station (S4-1.5). Our findings thus indicate that the high concentrations of dissolved PBDEs in the southern SoG are produced by desorption of PBDEs from sewage particles during their dispersion in seawater, and that the dispersion of PBDE in the SoG occurs mostly in dissolved form rather than as fine particles produced by the fragmentation of the sewage particles. This major finding was supported by: a) progressively smaller particulate PBDEs contribution to the total PBDE load at stations away from the Iona effluent (e.g. S1, 40% pPBDEs/60% dPBDEs, vs. 13% pPBDEs/87% dPBDEs @ S2, vs 1% pPBDEs/99% dPBDEs @ S4-1.5); b) fractionation between congeners of different particle-reactivity during the initial dilution and dispersion of the effluent (i.e. faster desorption of less brominated congeners from 226 sewage particles: % particulate BDE-47 dropped from 90 to 4% in the IDZ of the Iona plume compared to effluent vs. a drop from 90 to 70% for particulate BDE-209); and c) congeners fractionation in the dissolved PBDE depth profiles measured at Station S4-1.5 and when comparing congeners distribution at different stations in the Salish Sea. These findings confirm that dPBDEs dominate the PBDE load in the southern SoG and are produced by desorption from sewage particles, as they disperse from the particulate point source at the Iona outfall. Thus, although the Iona plume is not a direct point source of dissolved PBDEs, the plume is still the main ultimate source of the dPBDEs in the water column in southern SoG. Once released in dissolved form, the dPBDEs are gradually removed by particle scavenging or exported to the Pacific Ocean with the estuarine circulation. The dominance of dissolved PBDE in SoG seawater also suggests that PBDEs enter the food chain mostly by uptake of dissolved PBDE from seawater rather than ingestion of contaminated particles. Our findings show significant temporal variability of PBDE concentrations related to intermediate water circulation and indicate incomplete mixing of the Iona plume in the southern SoG. Annual samples from Station S2, situated just north of the Iona outfall, exhibited high temporal variability in particulate PBDE concentrations, but relatively constant and high concentrations in dissolved PBDEs. In contrast, samples from Station S4-1.5, situated in the middle of the southern SoG, exhibited invariably low particulate PBDE concentrations but relatively high and variable dissolved PBDE concentrations. The high variability of particulate PBDE concentrations at S2 is attributed to the proximity of this station from the point of discharge and to its location within the dispersion zone of the Iona plume. It could also in part be due to its proximity to Burrard Inlet, which is another potential source of pPBDEs into the SoG. Indeed, within the shallow Burrard Inlet, we observed high concentrations of pPBDEs when fast tidal currents promoted the resuspension of contaminated sediments. However, whether these recurring resuspension events export significant amounts of pPBDEs from Burrard Inlet to the SoG remains to be determined. Temporal variability of the dPBDEs concentrations observed at Station S4-1.5 can be explained by intermediate water circulation in the SoG, such that, when the sampled seawater is directly fed by the eastern boundary current entering SoG and transiting near the Iona outfall 227 before reaching the sampling location, its dissolved PBDE concentrations are high. In contrast, when the sampled seawater has resided in SoG for a longer time (ca. 160 days, the residence time of intermediate water in the SoG), its dissolved PBDE concentrations are low, due to mixing and removal of dPBDEs by scavenging while circulating within SoG. Our study thus indicates that in general the Iona plume is not well-mixed in the southern SoG, and that at our time series Station S4-1.5, the water column is subject to turbulent mixing between the water coming from the Haro Strait with the boundary current and older seawater leaving the SoG after residing in this basin for several months. This observation is based on a new method we developed to establish the ‘age’ of the intermediate water (50-150 m) sampled at our time series Station S4-1.5, by comparing the temperature at 170 m at S4-1.5 relative to the temperature recorded at the Ocean Network Canada East node. ‘New SoG seawater’ comes from the south and has passed recently by the Iona fall, while ‘old SoG seawater’ comes from the north and has been out of contact from the Iona fall for several months. The invariably high dissolved PBDEs concentration measured at Station S2 is explained by its location within the eastern boundary current. Determining the ‘age’ of water sampled in SoG could be very useful to many studies investigating biological or chemical processes within SoG. The close link between temporal variability in PBDEs concentrations and water circulation in the SoG (including tides) demands a multidisciplinary approach involving biogeochemists and physical oceanographers to fully understand the impact and fate of PBDEs discharged in the SoG. Our findings suggest that most of the PBDEs discharged in the SoG are scavenged into the underlying sediments, but a significant fraction of mono- and di-brominated congeners (some of which have been produced by debromination of manufactured congeners) are exported in dissolved form to the Pacific Ocean. The total quantifiable dissolved PBDE concentrations at Stations NG, HS and JF2 are much lower than in the southern SoG (ca. < 10pg/L vs. 300 pg/L), indicating either dilution of dissolved PBDE derived from the Iona effluent by Pacific water entering the SoG through the Haro Strait and Juan de Fuca Strait or removal to the sediment by scavenging on settling particles. Since the less brominated congeners are desorbed faster from sewage particles and re-adsorbed slower on marine particles, a larger fraction is exported to the Pacific by currents, while 228 the more brominated congeners desorbing at a slower rate and re-adsorbing faster, are almost entirely removed by burial in SoG sediments. Export of a significant fraction of congeners to the Pacific seems limited to mono- and di-BDEs. These congeners only account for a very small fraction of manufactured congeners and are likely produced by debromination prior to discharge. The Salish Sea Box Model was used to investigate the processes that control the concentrations of dissolved PBDEs in SoG. The model was run for dissolved BDE-47 and 99, and used Vancouver WWTP and Victoria WWTP inputs measured in 2004 (Dinn et al., 2012b) and input from the Fraser River, based on our measurements of PBDE concentrations during the freshet and in winter. The major findings of the model runs are: a) Even though the Fraser River has low dissolved PBDE concentrations, its high flow rate results in a PBDE discharge rate into SoG comparable to that of the Iona plume. b) The model predicts much lower PBDE concentrations than those measured in the southern SoG, which suggest either that there are additional sources, yet to be quantified, such as urban run-off and atmospheric deposition, or that the input from the Iona plume has increased in recent years or has been analytically underestimated. Our findings clearly document the desorption of PBDE from sewage particles and their dispersion in the SoG predominantly in dissolved form, and the systematic fractionation of PBDE congeners during desorption from sewage particles and re-adsorption onto marine particles. The data suggest that most of the discharged PBDEs are removed by scavenging into the SoG sediment, but a significant fraction of the mono- and di-brominated congeners are exported to the Pacific. However, quantitatively predicting the behavior of PBDEs in the SoG will require the determination of adsorption and desorption rate constants on different particle surfaces (sewage particles, river particles, cells of dominant phytoplankton species, etc.), the quantification of air-sea exchanges, the refinement of the estimates of PBDE input from the WWTPs and Burrard Inlet, and the identification of any other sources needed to account for PBDEs rates of accumulation in sediments and of export to the Pacific. The rate of removal from the water column by scavenging also needs to be quantified better, potentially by using a conservative tracer of WWTP effluent such as anthropogenic Gd. In addition, reverse scavenging 229 must be confirmed as the mechanism responsible for the addition of dissolved PBDEs to the deep water of the SoG. 5.1.2 PCBs Studying the behavior of PCB discharged in the marine environment is particularly challenging because PCBs are distributed among a large number of different congeners occurring at low concentration, which limits the precision of their measurements and obfuscate their general behavior in the environment. To mitigate the latter problem, it is customary to group congeners into homolog categories based on their degree of chlorination. Although providing a means to better highlight their transformation in the environment, that does not address the precision of the measurements. In addition, constrained by the cost of analysis, the database generated in this study is more limited than for PBDE and leads to more tentative conclusions. Nonetheless, the data clearly confirm that the wastewater outfalls are not the main source of PCB to the SoG. The industrialized zones on the shore of Burrard Inlet appear to be an important source but its quantification needs a targeted monitoring program to measure PCB flux associated with the ebbing and flooding tidal flows at the mouth of the inlet. On average, the net export of PCBs from the Burrard Inlet should be equal to the addition of PCBs to its water from all the point sources in the inlet minus the amount removed to Burrard sediment. However, quantifying input from Burrard Inlet may be further complicated by the presence of multiple different sources of PCB within the Inlet which could produce large temporal and spatial variabilities. While Burrard Inlet appears to be a significant source of PCBs, the relatively small difference in concentrations between the waters of Burrard Inlet and the SoG (3 – 6 fold) is insufficient to produce a tidal flow of PCB high enough to account for the level of PCBs measured in the SoG, and other potential sources need to also be evaluated, in particular the Fraser River and atmospheric input. In addition, since PCB concentrations were only measured once at one location in the southern SoG, additional measurements are needed to assess the spatial variability of PCB concentration in the Salish Sea to better constrain the PCB inventory in the SoG and the export (if any) of PCB to the Pacific Ocean. 230 Notwithstanding the complex and time varying source of PCBs to Burrard Inlet (Figure 4.13), Burrard Inlet is one of the main points of entry of PCBs into the SoG, and PCB homologs distribution observed in this study confirmed some of the expected behaviors of PCB during dispersal from Burrard Inlet to coastal waters. For instance: at Station 3b, particulate and dissolved PCB concentrations increase significantly during tidal resuspension of sediment (Figure 4.12). However, while the homolog distribution of particulate PCBs did not change significantly, that of dissolved PCB changed dramatically, with a decrease in tri- to hexa-CB concentration and a sharp increase in hepta- to deca-CBs (Figure 4.12). This indicates that the increase in dissolved PCBs was not due to desorption from resuspended sediments, which is expected if resuspension is frequent, but came from a different, yet to be identified, source. The dissolved PCB homolog distribution measured at S2 during flood (2013) and ebb (2014, 2015) suggests that the penta- to deca-CBs added to the SoG from Burrard Inlet are rapidly removed from the dissolved pool (Figure 4.2). A similar trend is observed when comparing the average homologs distribution at S2 and S4-1.5 (Figure 4.5). This observation suggests preferential removal of the more hydrophobic congeners added to the SoG from Burrard Inlet by particle scavenging. Once PCB-contaminated seawater and particles have been in contact long enough (S4, S1, and S2 during flood in December 2013), there is a clear increasing trend in particulate to dissolved partitioning with the degree of hydrophobicity of the PCB homologs (Figure 4.13). Such trend was not found in Burrard Inlet because of recent addition of different congeners from different sources. 5.2 Future studies 5.2.1 Atmospheric deposition of PBDEs into the Strait of Georgia Increasing concentrations of dissolved PBDEs towards the surface were observed in May 2017 and April 2018, which suggests atmospheric deposition of PBDEs from the atmosphere. Also, it is hypothesized that the high dissolved BDE-209 concentration at Station P26 in the Pacific Ocean comes from the atmospheric deposition via aerosols. Thus, it is necessary to investigate this further and compare it with the Fraser River input to estimate the relative importance of the two sources. 231 Atmospheric deposition can be classified into three types: dry deposition, wet deposition, and diffusive air-sea exchange. First, dry deposition refers to the deposition of contaminants (e.g. PBDEs) into the seawater through particle settling. To quantify the dry deposition flux, it is necessary to know the PBDE concentrations in air particles (per volume) and the particle deposition velocity (Jiménez et al., 2015). The former parameter can be obtained by collecting air particle samples using a large volume sampler, while the later parameter is reported in the literature. It must be noted that the particle deposition velocity is influenced by many factors, such as wind speed and humidity. Although limited data is available in the literature, it may not be suitable to reflect the real situation in the Salish Sea and areas around Station P26. Thus, extra steps may be needed to quantify this parameter in our research area. Second, wet deposition refers to the deposition of contaminants through precipitation, such as rain and snow. Similar to that of dry deposition, the PBDE concentrations in the rain or snow and the precipitation rate are needed to calculate the wet deposition flux. The former one can be obtained by collecting a large volume of rainwater in metal containers, such as aceton-cleaned kegs while the later one can be obtained from local meteorological data. Third, the diffusive air-sea exchange is the transfer of contaminants in gas form between the atmosphere and surface seawater. The transfer through the thin layer between air and sea is the rate-limiting step. The simplified model to calculate the air-sea exchange is the stagnant film model, which needs the measurement of the concentrations in the atmosphere and surface water, and gas transfer velocity. The estimation of the gas transfer velocity needs the thickness of the layer, which can be quantified from wind speed and 222Rn in the mixed layer. However, this model assumes steady state and a stagnant surface boundary layer, which may not always be the case. In the SoG, the expected result would be a positive net atmospheric deposition (deposit from air to sea) into the seawater. In case the net deposition is negative (release from sea to air), we may want to re-evaluate the importance of Fraser River using the mass balance and may need to find other sources (such as Lion’s Gate WWTP) to compensate for the loss of PBDEs into the atmosphere. In the Pacific Ocean, since the concentrations of PBDEs in the open ocean are extremely low (Table 1.3), a positive net atmospheric deposition is expected. 232 5.2.2 PBDEs’ interaction with particles One of the findings in this thesis is the fractionation of PBDEs between water and particles, both biogenic particles (e.g. phytoplankton) and sewage particles, including adsorption and desorption. Although the results can be explained using the adsorption and desorption hypothesis, a quantitative study of these processes is still missing. Several experiments are needed to answer this question, especially the determination of adsorption and desorption rate constants. For sewage particles, the experiments could be done using 14C labelled BDE-47, 99, 153 and 209. Since sewage particles are the source of PBDEs into the SoG, the experiment could focus on the desorption of PBDEs from these particles to calculate the desorption rate constant. To do this experiment, wastewater samples, and its containing sewage particles, could be provided by our research partner, Metro Vancouver wastewater treatment plant. To these wastewater samples, 14C labelled-dissolved PBDE congeners could be added at concentrations environmentally relevant, and sufficient time would be allowed in order for the 14C labelled-dissolved PBDE congeners to reach chemical equilibrium with the wastewater and sewage particles within the sample. The desorption experiment can then start by mixing 14C-labelled sewage particles into PBDE-free synthetic ocean water (SOW). At each time point, an aliquot, containing particles, will be sampled, followed by the separation of particles from SOW. 14C-PBDEs in SOW will be extracted using 1-Octanol. The 14C activity will then be quantified in both particles and 1-Octanol phase using the scintillation counter. For phytoplankton three processes must be considered: adsorption of PBDEs onto the cell surface, the diffusion of PBDEs into the cell, and the depuration of the cell (release PBDEs back to water). The general procedure is the same as that of sewage particles. However, it is quite challenging to study the transfer of PBDEs through cell membranes. Many factors will influence the result, such as the DOC content, colloid, temperature, particle size and properties (e.g. fine particles vs coarse particles, and biogenic particles vs sewage particles vs river particles). First, since PBDEs are hydrophobic, DOC will compete with particles to adsorb PBDEs. It is necessary to repeat the same experiment under different DOC concentrations to investigate the influence of DOC. Second, colloid (particles < 0.2 μm) is ignored in most studies. Once in the water, it will change the bioavailability of PBDEs to 233 phytoplankton and also reduce the amount of truly dissolved PBDEs available for particles to adsorb. Thus, colloid should be removed by UV treatment for organic matters and chemical coagulation for other colloids in all experiments (Matilainen et al., 2010). Third, the temperature can significantly change the adsorption and desorption rate. The determination of rate constants should be performed under several different temperatures to mimic the situation in summer and winters. Fourth, the adsorption and desorption are also controlled by the surface area of particles. The calculation of the rate constant needs the surface area information. For sewage particles, particle size will be quantified using the Coulter Counter to estimate the total surface area of particles in all experiments. For phytoplankton, only cultures in the stationary phase will be used and the amount of bacteria will also be monitored. During the stationary phase, cells are alive without dividing or growing, which makes it easy to control the total cell surface area. 5.2.3 Development of passive sampler and field tests As is mentioned above, phytoplankton utilize the “truly dissolved” PBDEs and compete with other substances such as DOC and colloid. The sample collection method used at present cannot provide the “truly dissolved” concentrations, and it is time-consuming, labor-consuming and limits our ability to get high-quality data due to the sample size. Passive sampling may be a good way to solve this problem. Generally, passive sampling uses a piece of material, packing it into a sampler and soak it in the field for a certain amount of time. Once the contaminant is absorbed inside the material, this material will be processed to extract the contaminant for quantitative analysis. The result will then be converted into the concentration in the water. The preliminary experiment was done in summer 2018, confirming the possibility of using silicon rubber and low-density polyethylene (LDPE) as the passive sampler material (see Appendix A). However, several key questions remain: (1) What is the best way to extract PBDEs from the material, Soxhlet extraction, microwave-assisted extraction, ultrasound-assisted extraction or other methods? What is the recovery? (2) When will the material be saturated with PBDEs? (3) What are the size and thickness needed when deploying the sampler into the ocean? (4) For a certain amount of material, how long does it take to reach equilibrium with PBDEs in the ocean? Some other issues should also be considered, such as the prevention of biofouling and 234 colloid effects. Biofouling is a layer of microorganism (and sometimes animals) growing on the surface of the passive sampler. This will prevent the material from absorbing PBDEs, leading to inaccurate results. 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Land-use-based sources and trends of dissolved PBDEs and PAHs in an urbanized watershed using passive polyethylene samplers. Environmental Pollution, 238, 573-580. DOI:10.1016/j.envpol.2018.02.057 242 Appendices Appendix A Collecting PBDE samples in a traditional way is time-consuming (2~3 one-day cruises are needed) and labor-consuming (bring at least ~450 L seawater back to the lab each time). The concentration measured can only reflect the concentration at a particular time point instead of the time-integrated concentration over a period of time. In order to solve this issue, the passive sampling technique is a right choice. Passive sampling uses a specific material and merges it into the environment. Contaminants, especially those hydrophobic compounds, diffuse into the passive sampler and concentrate inside, which are significantly higher than that in the environment. Converting the concentration in the passive sampler to that in the environment is based on the kinetic model and further calibration. This method allows us to analyze the extremely low concentrations in the environment without having any below detection limit issues because contaminants are concentrated inside. The purposes of this small volume experiment are (1) to confirm whether silicon rubber (SR) and low-density polyethylene (LDPE) can absorb PBDEs or not, (2) to obtain adsorption and desorption rate constants and fit the result into models, and (3) to determine the time needed to reach the equilibrium. A.1 Method (1) Small volume experiment The purpose of this experiment is to learn the possibility of developing passive samplers using LDPE and SR. Five different experimental conditions were set up: LDPE (0.004" thick) with shaking, LDPE (0.01" thick) with shaking, SR (1/32" thick) with shaking, SR (1/16" thick) with shaking and SR (1/16" thick) without shaking. The shaking speed was 40 rpm for all shaking groups. All films were cut into 2.5 cm × 1.0 cm films, cleaned by Soxhlet extraction using enough ethyl acetate for 72 hours at ~ 97 °C and pre-weighed. DOC-free SOW was prepared by UV oxidation for 45 minutes and then spiked with 14C-BDE-153. The spiked SOW was used 24 hours after preparation, allowing PBDEs to reach the equilibrium with glass surface and thoroughly mixed with SOW. Each film was entirely immersed into 15 mL of the spiked solution without air bubbles on the surface. Due to the low density, an iron pin was used to go 243 through each LDPE film, ensuring the film was entirely in the solution. After a certain time, one film was separated from its solution, and the 14C-BDE-153 was extracted from the solution by adding 1 mL 1-Octonal and put on a shaker at 40 rpm overnight. 14C activities were retrieved by collecting the 1-Octonal layer on the surface of SOW and were measured as a function of time in SOW. (2) Large volume experiment Once SR is selected to be the ideal material for the passive sampler, a large volume experiment was performed to mimic the real situation in the ocean. In the small volume experiment, the 14C-BDE-153 concentration decreased significantly in the surrounding environment, which cannot reflect the real situation in the ocean. The purpose of this experiment is to try to maintain the PBDE concentration in the environment using a 20 L 14C-BDE-153 SOW, although there would still be a decrease of PBDEs in the water. Ten 1 cm × 1 cm 1/16'' SR films were cleaned as mentioned above. The 20 L 14C-BDE-153 SOW was prepared and used 36 hours after preparation. All films were then hanged on a thin titanium alloy wire with the same distance between films and fully soaked in the 14C labelled SOW. Samples were collected at different time points by retrieving one film and 1 L SOW. 14C was extracted and quantified in the same way as above. A.2 Results (1) PBDE affinity to iron oxide Unfortunately, the iron pin became rusty after shaking for 2 hours and eventually super rusty in two LDPE groups. An experiment of determining PBDE affinity to iron oxide was designed. This experiment was done by passing the 14C-labelled solution with iron oxide through a combusted 25 mm GF/F filter and collect the filter and filtrate. The 14C activity in the filtrate was retrieved using the same method mentioned above. The activities in filter, filtrate and empty vials were measured. The result (Table A.1) shows that there is no 14C left in the filtrate, which confirms that PBDEs have a very strong affinity to iron oxide. Thus, there is no result for LDPE groups in the experiment. 244 Table A.1: Iron oxide affinity experiment results. Group # Sample # Description Final DPM dpm Error (dpm) 1 Test 1 - Filter Activity on Fe2O3 Outside quench limit. Invalid data. Test 1 - SOW Activity in SOW -0.26 0.81 Test 1 - Vial Activity on Fe2O3 left in the vial Result not considered valid due to colour quench. 2 Test 2 - Filter Activity on Fe2O3 Outside quench limit. Invalid data. Test 2 - SOW Activity in SOW -0.47 0.81 Test 2 - Vial Activity on Fe2O3 left in the vial Result not considered valid due to colour quench. 3 Test 3 - Filter Activity on Fe2O3 Outside quench limit. Invalid data. Test 3 - SOW Activity in SOW -0.65 0.80 Test 3 - Vial Activity on Fe2O3 left in the vial Result not considered valid due to colour quench. Blank BLK1 Filter after filtering 15 mL DOC-free SOW 0 BLK2 Filter after filtering 15 mL DOC-free SOW BLK3 Filter after filtering 15 mL DOC-free SOW (2) Small volume experiment Figure A.1 shows the changes in 14C activity in films and SOW over time. For the shaking group of the same material (SR), it takes >60 hours to reach the equilibrium regardless of the thickness of SR. Since a longer time to reach equilibrium is expected with the thicker SR, this similarity confirms that equilibrium was not reached which may be caused by the volume of spiked SOW was too small to saturate the SR film. Furthermore, it takes a significantly longer time (>500 hours) to reach the equilibrium without shaking, proving that the initial rate-limiting step for the absorption of PBDE into SR is the diffusion through the aqueous diffusive boundary layer. Since there are strong currents in the ocean, the in-situ condition will be somewhat similar to the shaking group in this experiment, which has a thin boundary layer despite the fact that the liquid moving speed at the surface of SR in vials is much slower than that in the ocean. 245 Figure A.1: The 14C activity changes in SOW and film over time in different materials under different conditions. (3) Large volume experiment The large volume experiment did not provide good results (Table A.2). First, the 14C activity in SOW was expected to decrease over time, but in fact, it behaved randomly after 8 hours. The potential reason is the glass carboy. The 20 L glass carboy has a large surface area, which could adsorb lots of PBDEs. At the beginning of the experiment, it adsorbed 14C and compete with SR films. Once the 14C decreases to a certain level in the remaining SOW, a new equilibrium needs to be reached by desorbing 14C from the glass surface, which caused the increase of 14C in the SOW at 8, 64 and 150 hours. This can also explain why the 14C left in SOW in the small volume experiment was not 0 at the end, even after 250 hours (Figure A.1). The 14C on the glass surface was also retrieved by adding 1-Octonal. Second, the sampling time 246 was not designed well. Too many points were collected in the first 8 hours when the activity in SOW is still very low, while only a few data points were available after 150 hours when the 14C in the film changes significantly. All these issues prevented us from calculating the adsorption rate constant of SR. Table A.2: Large volume experiment results. Time (hours) 14C in SOW sample 14C in SR sample dpm/L Error (dpm) dpm Error (dpm) 0 17.34 0.66 0 0.32 1 17.09 0.66 0.61 0.37 2 17.29 0.66 0.36 0.37 4 15.71 0.66 0.87 0.37 8 16.14 0.65 1.54 0.38 16 14.71 0.65 3.15 0.39 32 15.18 0.65 5.17 0.40 64 16.64 0.66 11.49 0.43 150 20.85 0.67 16.56 0.45 275 18.83 0.66 23.79 0.49 550 10.90 0.63 68.63 0.65 A.3 Conclusions Overall, the initial experiment confirms that SR is an ideal material to adsorb PBDEs for long-term monitoring, even in areas with low PBDE concentrations. Although the first large volume experiment did not have ideal results, it pointed out the critical issues which can be improved in future experiments. Many questions need to be answered before applying this method in the fieldwork, as mentioned in Chapter 5.
Thesis/Dissertation
eng
Oceanography
Vancouver : University of British Columbia Library
Attribution-NonCommercial-NoDerivatives 4.0 International
Graduate
Sources, fractionation and fate of polybrominated diphenyl ethers and polychlorinated biphenyls in the Strait of Georgia, Canada
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