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Sedimentary tracers of sewage inputs to the southern Strait of Georgia Gordon, Kathleen 1997

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SEDIMENTARY TRACERS OF SEWAGE INPUTS TO THE SOUTHERN STRAIT OF GEORGIA by Kathleen Gordon B.Sc., The University of British Columbia, 1994 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE F A C U L T Y OF G R A D U A T E STUDIES (Department of Earth and Ocean Sciences) We accept this thesis as conforming to tffi required standard The University of British Columbia December 1997 © Kathleen Gordon, 1997 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of gAtirH A HO Occam 5ctg*)Cgs The University of British Columbia Vancouver, Canada D a t e frgcfcM&ga. 1, DE-6 (2/88) Abstract Sewage effluent has been discharged at depth to the Strait of Georgia just south of Vancouver since 1988, following primary treatment at the Iona Island Sewage Treatment Plant. The discharge is accomplished through a pair of semi-parallel diffusers between water depths of ~ 70 m and ~ 105 m that lie orthogonal to the bottom contours on the foreslope of the Fraser River Delta. Prior to the research reported here, knowledge was limited as to the transport pathways and depositional fate of the particulate matter in the effluent. Thus, the objective of this work is to investigate and apply a suite of sewage-specific tracers, in particular silver, stable carbon and nitrogen isotopes, and more commonly-considered contaminant metals (Cu, Pb and Zn) in an effort to define better the depositional footprint of the Iona sewage in southern Georgia Strait. Silver has the highest relative enrichment of any metal in sewage, and is expected to be an ideal candidate as a sewage tracer. That this is the case here is borne out by a well-defined band of high Ag concentrations (~ 400-800 ng/g) in sediments that extends along the foreslope north of the outfall by ~ 6 km and south by ~ 1 km. This pattern reflects transport of the effluent plume predominantly to the north with little lateral dispersion. The accumulation of silver in this area is unlikely to be due to authigenic precipitation of Ag2S or other sulphide phases, but is instead attributed to direct deposition of a very small amount of particulate sewage in which the silver content is highly enriched. Very high silver concentrations (1, 400 ng/g) are also observed in an area of Sturgeon Bank close to the Iona Island plant, where direct discharge of sewage occurred prior to 1988. In contrast, very low levels (~ 50 ng/g) are found in coarse-grained lag deposits in shallow regions of the delta. Sediments in the deep central basin of the Strait of Georgia host concentrations on the order of 130 ng/g. Significant enrichments of manganese oxides in the surface sediments of some cores from the central Strait are not matched by enhanced silver concentrations, suggesting that silver is minimally associated with manganese oxide phases in marine sediments. Neither stable carbon arid nitrogen isotope distributions nor concentration patterns for Cu, Pb and Zn show any associations in the Strait of Georgia with the pattern of sewage deposition defined by the silver data. The lack of sensitivity of these two groups of potential tracers is attributed to a coupling between low signal to background ratios and the substantial discharge of sediments (some 20 x 10^ m^/year) from the Fraser River which dwarfs sewage-specific inputs of the trace metals and the isotopes. Thus, of the various tracers investigated in this research, silver is uniquely appropriate. i i Table of Contents Abstract i i Table of Contents i i i List of Tables y List of Figures ix Acknowledgements xiv Chapter 1. Introduction 1 Chapter 2. Environmental Setting and History 7 2.1 Strait of Georgia 7 2.1.1 Circulation 7 2.1.2 Sedimentation 8 2.2 Sturgeon and Roberts Banks 9 2.3 The Iona Sewage Treatment Facility 11 2.3.1 History 11 2.3.2 Treatment 12 2.3.3 Disposal 13 2.3.4 Plume Dispersion 13 Chapter 3. Sewage Tracers 18 3.1 Coliform Bacteria and C. perfringens 18 3.2 Coprostanol 19 3.3 Linear Alkylbenzenes 21 3.4 Osmium Isotopes 21 3.5 Carbon and Nitrogen Isotopes 23 3.5.1 Carbon Isotopes 23 3.5.2 Nitrogen Isotopes 27 3.5.3 Carbon and Nitrogen Isotopes as Sewage Tracers 32 3.6 Silver 35 3.6.1 General Chemistry and Speciation 35 3.6.2 Distribution in Seawater 41 3.6.3 Solid Phases 45 3.6.4 Sediments 47 3.6.5 Anthropogenic Sources 47 3.6.6 Municipal Wastewater 49 Chapter 4. Results 51 4.1 Silver 51 4.2 Carbon and Nitrogen Isotopes 57 4.3Si /Al 64 4.4 Organic Carbon 64 4.4.1 C/N Weight Ratios 70 4.4.2 Sulphur 73 4.5 Major and Minor Element and Element Ratio Distributions 73 4.5.1 Manganese 73 4.5.2 Fe/Al 79 4.5.3 P/Al 79 4.5.4 Pb/Al 84 4.5.5 Cu/Al 84 4.5.6 Zn/Al 84 4.5.7 Correlations Amongst Trace Metals in Core A O 90 Chapter 5. Discussion 93 5.1 Silver as a Tracer of Circulation 93 5.1.1 Fraser River Foreslope 93 iii 5.1.2 Sturgeon Bank 96 5.2 Other Controls on the Distribution of Silver 98 5.2.1 Grain Size 98 5.2.2 Association of Silver With Specific Sediment Phases 100 5.2.2.1 Mn Oxides 100 5.2.2.2 Fe Oxides 101 5.2.2.3 Organic Matter and Sulphides 103 5.3 Other Tracers 105 5.3.1 Stable Isotopes of Carbon and Nitrogen 105 5.3.2 Trace Metals (Cu, Pb and Zn) 107 5.4 Past and Present Sedimentary Conditions 107 5.4.1 Historical Influences on Sturgeon Bank 107 5.4.2 Steady-State Conditions 108 Chapter 6. Summary and Conclusions 109 Bibliography I l l Appendix 1. Materials and Methods 124 A 1.1 Sample Collection and Locations 125 A 1.2 Inorganic Carbon 126 A 1.3 Total Carbon, Nitrogen, and Sulphur 127 A1.4 Major (Fe, Mn, Ti, Ca, K, Si, A l , Mg, P, Na) and Minor (Ba, Co, Cr, Cu, Mn, Ni , Pb, Rb, Sr, V , Y , Zn, Zr, I, Br, and Mo) Elements 130 Al.4.1 Majors Preparation 141 A 1.4.2 Minors Preparation 142 A 1.5 Total Silver 142 Al.5.1 Digest Method 1 142 Al.5.2 Digest Method 2 146 Al.5.3 ICP-MS Analysis 147 Al.5.4 Calculations 148 A1.6 Role of Particle Size 152 A1.7Lead 152 A l . 8 Seasalt Corrections 157 A1.8.1Chlorinity 157 A 1.8.2 Salt Correction 158 A 1.9 Carbon and Nitrogen Isotopes 159 A1.10Pb-210 160 Appendix 2: Sample Locations 165 Appendix 3: Sample Descriptions 171 Appendix 4: Data 182 iv List of Tables Table 1.1 Important contaminants in municipal wastewaters (after Bishop, 1983) 2 Table 3.1 Coprostanol concentrations in sewage effluent, sewage sludge, sewage contaminated sediments and relatively uncontaminated sediments from various locations. Values are in ppm. Note that the analytical detection limit for this compound is very low, which improves its utility as a tracer 20 Table 3.2 Linear alkylbenzene concentrations in sewage effluent, sewage sludge, sewage contaminated sediments and relatively uncontaminated sediments from various locations. Concentrations are in ppm. As for coprostanol, the sensitive detection limit makes L A B s a valuable tracer 22 Table 3.3 Values of 8 ^ C in C3 plants (Lajtha and Michener, 1994; Simenstad and Wissmar, 1985*) 24 Table 3.4a) Values of S ^ C and b) 8 1 5 N in marine, terrestrial, and sewage material. Values arein%o 33 Table 3.5 Metal concentrations and enrichments in sewage sludge and sewage particles. Metal concentrations are in ppm. Enrichment factors are the ratio of the metal concentration in sewage waste divided by the metal concentration in uncontaminated sediments or average shale. Average shale values from Bowen (1966) 36 Table 3.6 Metal concentrations and enrichments in sewage contaminated sediments. Metal concentrations are in ppm. Enrichment factors are the ratio of the metal concentration in the sediment divided by the metal concentration in uncontaminated sediments or average shale. Average shale values from Bowen (1966) 37 Table 3.7 Solubility constants for a) Ag compounds; and b) metal sulphides (Jenne et al., 1978; Krauskopf, 1979) 39 Table 3.8 Silver concentrations of various rocks and deposits. Values are from Smith and Carson (1977) unless noted otherwise. Concentrations are in ppm 42 Table 3.9 Silver concentrations in various marine deposits (Koide et al., 1986). Note that Whites Point deposits are impacted by sewage wastes 48 Table 4.1 Silver concentrations in surface sediments in ng/g north (N) and south (S) of the Iona outfall diffuser section. Sediments were sampled along transects running west to east from water depths of ~ 200 m to 20 m. Values are salt corrected. For sample locations see Figure 1.2 and Appendix 2 54 Table A 1.1 inorganic carbon analytical precision determined by analyzing six sub-samples from a single sample for each of the two coulometry systems. Inorganic carbon values are in weight percent 128 Table A 1.2 Total carbon, nitrogen, and sulphur analytical precision determined on six sub-samples of a given sample. Values are in weight percent. RSD=relative standard deviation 131 v Table A1.3 a) X R F instrument conditions for major elements; b) X R F instrument conditions for minor elements 132 Table A1.4 Accuracy of X R F analysis for major elements. Measured values are compared to the recommended value (R). Values are in weight percent of the oxide 133 Table A1.5 Accuracy of X R F analysis of minor elements. Measured values are compared to the recommended value (R). Values are in ppm 134 Table A1.6 Accuracy of X R F analysis of I and Br. Measured values are compared to the recommended value (R). Values are in ppm 135 Table A1.7 Accuracy of X R F analysis of Mo. Measured values are compared to the recommended value (R). Values are in ppm 136 Table A1.8 a) X R F instrument precision for major elements, determined by analyzing the same standard sample throughout the analyses. Values are in weight percent of the oxide; b) RSD (%) for major elements determined by analyzing six sub-samples from a single homogenized sample (Drysdale, 1990; Feeney, 1995) 137 Table A 1.9 a) X R F instrument precision for minor elements determined by analyzing the same standard sample throughout the analyses. Values are in ppm. b) RSD (%) for minor elements determined by analyzing six sub-samples from a single homogenized sample (Drysdale, 1990; Feeney, 1995) 138 Table A L I O X R F instrument precision for I and Br determined by analyzing the same standard sample throughout the analyses. Values are in ppm 139 Table A L U X R F instrument precision for Mo determined by analyzing the same standard sample throughout the analyses. Values are in ppm 140 Table A l . 12 Instrument settings for Ag analysis by ICP-MS 143 Table A1.13 Detection limit of redigest solutions analyzed by ICP-MS for the column and on-line methods using digest methods 1 (250 mg) and 2 (10 mg) 145 Table A 1.14 Accuracy of the on-line ICP-MS procedure for standard samples digested by method 1 and method 2. Values are compared to the recommended value. Both marine sediment standards and geological standards were used. Each number represents a different sample. Values are in ppb. 149 Table A1.15 a) Analytical precision of the on-line ICP-MS procedure using digest method 2 with new and used vials. Two different values were determined for each of the samples digested in the used vials. The first value was determined using a mass bias from the start of the analysis and a second using a mass bias determined at the end of the analysis; b) mass bias values determined at the start and end of the analysis 151 Table A l . 16 Instrument settings for Pb analysis by ICP-MS 153 Table A l . 17 Accuracy of the ICP-MS analysis of Pb using digest methods 1 and 2. Values of the marine sediment standards and geological standards are compared to the recommended value. Each number represents a different sample. Values are in ppm 155 Table A 1.18 Analytical precision for Pb analysis. 156 Table A1.19 Analytical precision estimate for S ^ N and S^Corg analysis determined by analyzing six sub-samples of a given sample 161 Table A1.20 Data for 2 1 0 P b analysis of cores A O , SG17, SG29, and SG42 163 Table A1.21 Data for 210pD analysis of core SG55 164 Table A2.1 Location and water depth of cores and grab samples (gs) collected from the Strait of Georgia. Date of collection and core length are indicated. Water depths for cores SGI, SG2, SG56, AG51, and AG59 were determined from a bathymetry map of the Strait of Georgia (L/C-3463), Canadian Hydrographic Service 166 Table A2.2 Location of cores collected from Sturgeon Bank and Roberts Bank. Date of collection and core length are indicated. Cores were sampled at low tide when the surface was exposed to the atmosphere 169 Table A2.3 Location of cores and surface samples collected by the Institute of Ocean Sciences ("59" cores) and Simon Fraser University. Date of collection is indicated. Water depths for the "59" cores and coordinates for samples W l - l a , Wl-2a, Wl-3a, BPt-la, BPt-2a, BPt-3a, A14a-1, and A14b-1 were determined from a from a bathymetry map of the Strait of Georgia (L/C-3463), Canadian Hydrographic Service 170 Table A3.1 Description of core and grab samples (gs) collected from the Strait of Georgia. 172 Table A3.2 Description of core samples collected from Sturgeon Bank and Roberts Bank. 177 Table A3.3 Description of core and surface samples collected by the Institute of Ocean Sciences ("59" cores) and Simon Fraser University 179 Table A4.1 Ag, Pb, S^Corg, 8 ^ n , Corg, Cinorg, total carbon, nitrogen and sulphur, C/N and CI in surface samples from the Strait of Georgia. Values are on a salt free basis, except for chlorine and isotopes of carbon and nitrogen. Isotopes of carbon are relative to PDB and nitrogen to air. The detection for N was approximately 0.05% (<D.L.=less than detection limit) 183 Table A4.2 Minor element data and I/Corg ratios for surface samples from the Strait of Georgia. Values for I/Corg ratios are multiplied by 10^. Values are on a salt free basis and in units of ppm. The detection for Mo was approximately 3 ppm (<D.L.=less than detection limit). Note that iodine values less than 10 ppm are unreliable 187 Table A4.3 Major element data for surface samples from the Strait of Georgia. Values are on a salt free basis and in units of weight percent 189 vn Table A4.4 Minor and major element to aluminum ratios for surface samples from the Strait of Georgia. Values are multiplied by 10^ except for Ag/Al , T i /A l , and P /Al which are multiplied by 10^, 10^, and 10^, respectively. Values are listed on a salt free basis 191 Table A4.5 Ag, Pb, S^Corg, S ^ N , Corg, Cinorg, total carbon, nitrogen and sulphur, C /N and CI in core samples from the Strait of Georgia. Values are on a salt free basis, except for chlorine and isotopes of carbon and nitrogen. Isotopes of carbon are relative to PDB and nitrogen to air. The detection for N was approximately 0.05% (<D.L.=less than detection limit) 195 Table A4.6 Minor element data and I/Corg ratios for core samples from the Strait of Georgia. Values are on a salt free basis and in units of ppm. Cores 5903, A G 17 and AG54 were not analyzed. Note that iodine values less than 10 ppm are unreliable 200 Table A4.7 Major element data for core samples from the Strait of Georgia. Values are on a salt free basis and in units of weight percent. Cores 5903 and VG1 were not analyzed.... 203 Table A4.8 Minor and major element to aluminum ratios for core samples from the Strait of Georgia. Values are multiplied by 10^ except for Ag/Al , T i /A l , and P/Al which are multiplied by 10^, 10^, and 10^, respectively. Values are listed on a salt free basis 207 Table A4.9 Silver concentrations for surface sediments from the same site but sampled in different years. Year and month of sampling are indicated with months in brackets. Each value represents a different sample. Values are in ppb. Sample locations are listed in Appendix 2. Sample 5903 was collected in 1993 by the Insititute of Ocean Sciences and samples 1995* were collected by Simon Fraser University. .: 215 Table A4.10 Silver concentrations in ppb for surface sediments from other locations in British Columbia. Samples from Saanich Inlet, a seasonally anoxic basin, were sampled from the middle of the inlet with samples SAG1, SAG3 and SAG4 from near the head of the inlet (Francois, 1987). Howe Sound is located north of the Strait of Georgia, samples KD71 and KD74 are located near Britannia Mine and KD18 is located northeast of Bowen Island in the outer basin of Howe Sound (Drysdale, 1990). Jervis and Knight Inlets are located up the coast and are oxic inlets. Indian Arm is located to the northeast of Vancouver and connects to Burrard Inlet 216 Table A4.11 Silver concentrations in ppb for particle size fractions for various samples. Other samples were separated into the same particle size fractions and used to determine relationships between particle size and elemental data 217 viii List of Figures Figure 1.1 Sampling locations in the Strait of Georgia. Cores used in this study are indicated with a box around the label. For other cores only the top sample was used (0-1 cm or 0-2 cm, see Appendix 2). The 59-series cores were collected in 1993 by the Institute of Ocean Sciences. Samples W9, W10, A14a-1, A14b-1, and transects W l and BPt were collected in 1995 by Simon Fraser University (Table A2.3, Appendix 2). V G cores were collected in 1994; SG cores and samples AO, K A 1 , KA2 , W6, W7, and W8 from Sturgeon Bank were collected in 1995; and A G cores, HC samples and A14 and BPt-1 were collected in 1996 (Tables A2.1 and A2.2, Appendix 2). Isobaths are in metres 5 Figure 1.2 Locations of three sampling transects to the south (S) and six transects to the north (N) of the Iona sewage outfall. Sampling sites on Sturgeon Bank are also indicated. Samples along the transects were collected at water depths of approximately 20, 30, 40, 50, 70,90, 110, 130, and 170 m. For transects 3S, 2S, and IS there is no sample from 20 and 40 m depth and for transects 5N and 6N there is an addtional sample at 200 m depth. Core VG1 is located immediately west of the diffuser section of the outfall that extends from a water depth of ~ 70 m to ~ 105 m. Isobaths are in metres 6 Figure2.1 Sediment grain size on Sturgeon Bank using Wentworth classification (Feeney, 1995). ; 10 Figure 2.2a) Effluent plume dispersion from an outfall in the absence of a pycnocline and b) in the presence of a pycnocline under different current velocities (u) (Koh, 1983) 14 Figure 2.3 Distribution pattern of Iona sewage plume as indicated by a dye tracer (GVRD, 1989a).... 16 Figure 2.4 Contour pattern of trace metals in sediments near a California outfall as indicated by zinc isopleths in ppm (Hershelman et al., 1981) 17 Figure 3.1 Values of S ^ C for C3, C4, and C A M photosynthetic pathway plants (Rundel et al., 1988) 25 Figure 3.2 Changes in the 8' ^C of (a) particulate inorganic carbon (PIC) and (b) suspended or sinking particulate organic matter (POM) from JGOFS's North Atlantic Bloom Experiment Site, April 25-May 31, 1989 (c) changes in ocean mixed layer [TC02] and [C02(aq)] at the same location and time period (Rau et al., 1992). 26 Figure 3.3 P O M 8 1 3 C versus (a) surface water temperature and (b) surface water [C02(aq)] at atmospheric equilibrium (Rau et a l , 1991) 28 Figure 3.4a) Reduction of NO3" concentrations with time and b) increase in 8 X ^N values of surface suspended particles (Altabet et al., 1991). These data were collected during the course of a phytoplankton bloom in the North Atlantic 30 Figure 3.5 The 8 A ^N of animals collected from marine, freshwater, and land ecosystems (Minagawa and Wada, 1984).., 31 ix Figure 3.6a) Profile of 8 1 3 C values of an east-west transect through the New York Bight and b) a north-south transect profile (Burnett and Schaeffer, 1980) 34 Figure 3.7 Relationship between Ag and coprostanol (unfilled circles), L A B s (triangles), Corg (filled circles), and spores of Clostridium perfringens (squares) in sediment trap samples from the New York Bight (Bothner et al., 1994) 38 Figure 3.8 Dissolved Ag concentrations versus depth measured in the Pacific Ocean. Dissolved Cu concentrations are shown for comparison (Martin et al., 1983). 43 Figure 3.9 Vertical profiles of total (unfiltered) silver concentrations (pM) in oceanic waters. Values indicated with circles, squares and diamonds are from the North Atlantic, South Atlantic and North Pacific, respectively (Flegal et al., 1995) 44 Figure 3.10 Relationship between total silver and silicate concentrations in the eastern Atlantic (Flegal et al., 1995) 46 Figure 4.1 Distribution of Ag in Strait of Georgia surface sediments. The sample locations on which this map is based are shown in Figure 1.1 52 Figure 4.2 Distribution of Ag in surface sediments near the Iona sewage outfall and on Sturgeon Bank near the Iona sewage treatment plant. The sample locations on which this map is based are shown in Figure 1.2 53 Figure 4.3 a) Vertical distribution of Ag in sediment cores from the Strait of Georgia (SG55, SG4, V G 1 , 5903), west of Burrard Inlet (AG54), north of the Iona outfall (AG 17, SG29), and Sturgeon Bank (A12). Cores SG29 and AG17 with similar Ag values were sampled one year apart at approximately the same location. The average shale value is shown for comparison; b) vertical distribution of Ag in core A O with cores A12, SG55, SG29 and AG17 shown for comparison. Note the different scales for the two figures 56 Figure 4.4 a) Vertical distribution of Ag/Al ratios in sediment cores from the Strait of Georgia (SG55, SG4), north of the outfall (AG17, SG29), west of Burrard Inlet (AG54) and Sturgeon Bank (A12); b) vertical distribution of Ag/Al ratios in core A O with cores A12, SG55, SG29 and A G 17 shown for comparison. The value of the ratio in average shale is indicated for comparison (Bowen, 1966). Note the different scales for the two figures and the similar vertical distributions of Ag/Al ratios and Ag in the same cores with Figure 5.3 58 Figure 4.5 a) Silver concentrations in mud (< 63 Jim), fine sand (63-125 |J.m), and coarse sand (> 125 ^m) size fractions of selected surface samples (except for SG56 which was sampled at 2-3 cm). SG56 is from the deep waters of the Strait and was very fine grained (100% < 63 (j.m). A14 is from Roberts Bank and A12 and HC2 are from Sturgeon Bank; b) Samples from a transect north of the outfall (2N). Water depth decreases from SG32 to A G 13. Sample locations are shown in Figures 1.1 and 1.2 and in Tables A2.1 and A2.2 in Appendix 2. . 59 Figure 4.6 Distribution of 8 ^ N in surface sediments of the Strait of Georgia. Sample 5911 is not included. Sample locations are shown in Figure 1.1 60 Figure 4.7 Distribution of S^Corg in surface sediments of the Strait of Georgia. Sample 5912 is not included. Sample locations are shown in Figure 1.1 61 x Figure 4.8 Distribution of 8 l 5 N in surface sediments near the Iona outfall and Iona sewage treatment plant. Sample locations are shown in Figure 1.2 62 Figure 4.9 Distribution of S^Corg in surface sediments near the Iona outfall and Iona sewage treatment plant. Sample locations are shown in Figure 1.2 63 Figure 4.10 Vertical distributions of S ^ N in sediment cores from the Strait of Georgia (SG55, SG4, VG1), north of the Iona outfall (AG17, SG29), west of Burrard Inlet (AG54), and Sturgeon Bank (AO) 65 Figure 4.11 Vertical distributions of 8 l 3 Corg in sediment cores from the Strait of Georgia (SG55, SG4, VG1), north of the Iona outfall (AG17, SG29), west of Burrard Inlet (AG54), and Sturgeon Bank (AO) 66 Figure 4.12 Distribution of Si /Al ratios in surface sediments of the Strait of Georgia for samples 59-series, VG1-5, SG1-32, SG39-59, AO, A12, K A 1 , K A 2 , W6, W7, and W8 only. Sample locations are shown in Figure 1.1 67 Figure 4.13 Vertical distribution of Si /Al ratios in sediment cores from the Strait of Georgia (SG55, SG4), north of the Iona outfall (AG 17, SG29), west of Burrard Inlet (AG54), and Sturgeon Bank (A12, AO) 68 Figure 4.14 Distribution of organic carbon (Corg) in surface sediments of the Strait of Georgia. Values are in weight percent. Sample 5912 is not included. Sample locations are shown in Figure 1.1 69 Figure 4.15 Distribution of organic carbon (Corg) in surface sediments near the Iona outfall and Iona sewage treatment plant. Sample locations are shown in Figure 1.2 71 Figure 4.16 Vertical distributions of Corg in sediment cores from the Strait of Georgia (SG55, SG4, VG1), north of the Iona outfall (AG17, SG29), west of Burrard Inlet (AG54), and Sturgeon Bank (A 12, AO) 72 Figure 4.17 Distribution of organic carbon to nitrogen (C/N) weight ratios in surface sediments of the Strait of Georgia. Nitrogen values for several samples are below the detection limit (see Table A4.1, Appendix 4), which precluded their inclusion in the map. Sample locations are shown in Figure 1.1 74 Figure 4.18 Vertical distribution of Corg/N ratios in sediment cores from the Strait of Georgia (SG55, SG4, VG1), north of the Iona outfall (AG17, SG29), and west of Burrard Inlet (AG54). Cores A12 and A O with nitrogen values below the detection limit are not included. 75 Figure 4.19 Distribution of salt-free sulphur in surface sediments of the Strait of Georgia. Sample locations are shown in Figure 1.1 76 Figure 4.20 Vertical distributions of salt-free sulphur in sediment cores from the Strait of Georgia (SG55, SG4, VG1), north of the Iona outfall (AG17, SG29), west of Burrard Inlet (AG54), and Sturgeon Bank (A12, AO) 77 xi Figure 4.21 Distribution of Mn/Al ratios in surface sediments of the Strait of Georgia for samples 59-series, VG1-5, SG1-32, SG39-59, AO, A12, K A 1 , K A 2 , W6, W7, and W8 only. Sample locations are shown in Figure 1.1 78 Figure 4.22 a) Vertical distribution of Mn/Al ratios in sediment cores from the Strait of Georgia (SG4), north of the outfall (SG29), and Sturgeon Bank (A12, AO); b) and core SG55 from the deep basin of the Strait. Core SG4 is shown for comparison. Note the different scales for the two figures. The value of the ratio in average shale is indicated in the first figure for comparison (Calvert and Pedersen, 1993) 80 Figure 4.23 Distribution of Fe/Al ratios in Strait of Georgia surface sediments for samples 59-series, VG1-5, SG1-32, SG39-59, AO, A12, K A 1 , KA2 , W6, W7, and W8 only. Sample locations are shown in Figure 1.1 81 Figure 4.24 Vertical distribution of Fe/Al ratios in sediment cores from the Strait of Georgia (SG55, SG4), north of the Iona outfall (AG17, SG29), west of Burrard Inlet (AG54), and Sturgeon«ank(A12-AO). ". 82 Figure 4.25 Vertical distribution of P/Al ratios in sediment cores from the Strait of Georgia (SG55, SG4), north of the Iona outfall (AG17, SG29), west of Burrard Inlet (AG54), and Sturgeon Bank (A 12, AO) 83 Figure 4.26 Distribution of Pb/Al ratios in surface sediments of the Strait of Georgia. Sample locations are shown in Figure 1.1 85 Figure 4.27 Vertical distribution of Pb/Al ratios in sediment cores from the Strait of Georgia (SG4), north of the Iona outfall (AG 17, SG29), west of Burrard Inlet (AG54) and Sturgeon Bank (A12, AO). The value of the ratio in average shale is indicated for comparison (Calvert and Pedersen, 1993) 86 Figure 4.28 Distribution of Cu/Al ratios in surface sediments of the Strait of Georgia for samples 59-series, VG1-5, SG1-32, SG39-59, AO, A12, K A 1 , K A 2 , W6, W7, and W8 only. Sample locations are shown in Figure 1.1 87 Figure 4.29 Vertical distribution of Cu/Al ratios in sediment cores from the Strait of Georgia (SG55, SG4), north of the Iona outfall (SG29), and Sturgeon Bank (A12, AO). The value of the ratio in average shale is indicated for comparison (Calvert and Pedersen, 1993) 88 Figure 4.30 Distribution of Zn/Al ratios in surface sediments of the Strait of Georgia for samples 59-series, VG1-5, SG1-32, SG39-59, AO, A12, K A 1 , K A 2 , W6, W7, and W8 only. Sample locations are shown in Figure 1.1 89 Figure 4.31 Vertical distribution of Zn/Al ratios in sediment cores from the Strait of Georgia (SG55, SG4), north of the Iona outfall (SG29), and Sturgeon Bank (A12, AO). The value of the ratio in average shale is indicated for comparison (Calvert and Pedersen, 1993) 91 Figure 4.32 Vertical distribution of Ag/Al , Pb/Al, Cu/Al , and Zn/Al in core A O . The value of the ratios in average shale are indicated for comparison (Bowen, 1996; Calvert and Pedersen, 1993). Enrichment factors represent the maximum metal to A l ratio in the core normalized to the ratio in average shale 92 Figure 5.1 Distribution of fecal coliform in sediments near the Iona sewage outfall (GVRD, 1995) 95 xii Figure 5.2 Ln (excess 210pD) as a function of the cumulative mass in core SG55 97 Figure 5.3 Correlation between silver (Ag) and organic carbon (Corg) in surface sediments of the Strait of Georgia 99 Figure 5.4a) Vertical distribution of Ag and Mn/Al ratios in core SG4; b) and in core SG55. 102 Figure 5.5a) Vertical distribution of Ag, Fe/Al and P/Al ratios in cores SG4; b) SG55; and c) AG54 104 xiii Acknowledgements I would like to thank the many people who contributed their time and effort to this study. Thanks are offered to those who helped collect samples on the Vector cruises and to the captain and crew of the Vector and the coast guard Hovercraft and to Paul Harrison's group for time on the hovercraft. I am especially grateful to John Crusius and David Sage who provided valuable information on the methods used in the silver procedure and for the use of their developed on-line method. Bente Nielsen provided the isotope data and Rob Macdonald the Pb-210 data while Bert Mueller kept the ICP-MS in proper working order; I thank them all. Maureen Soon kindly provided many CNS data and information on lab procedures, in addition to cheerful conversation. Thanks are also offered to my supervisor Tom Pedersen for his helpful advice, patience, enthusiasm, and words of encouragement. Financial support for this study was provided by the Green Plan through Dr. Rob Macdonald at the Institute of Ocean Sciences, Sidney, B. C. xiv Chapter 1. Introduction Typically, silver is enriched more than two hundred fold in sewage waste compared to uncontaminated marine sediments which is a higher enrichment on average than any other metal (Ravizza and Bothner, 1996; Forstner and Whittman, 1981; Samhan and Ghobrial, 1987). Indeed, high silver contents are typically found in sediments near sewage outfalls and sludge dumping sites (Abu-Hilal et al., 1990; MacKay et al., 1972; McGreer, 1982; Hershelman et a l , 1981; Papakostidis et al., 1975). These observations indicate that silver is a potential tracer of sewage wastes in the marine environment (Gross, 1972; Rutherford and Church, 1975; Bothner et al., 1994). Potential passive and active tracers of sewage particles were reviewed by Vivian (1986). Passive tracers are components already present in sewage, while active tracers are substances that are added specifically to study the fate of sewage in the environment. Active tracers such as radioactive substances (e.g. 110mAg) and dyes (rhodamine) persist for the short term only whereas passive tracers can build an integrated picture of the distribution and accumulation of sewage waste over time and space (Vivian, 1986). Passive tracers include natural substances (coprostanol), synthetic organics (linear alkyl benzenes, silicones), stable isotopes (C, N , and Os), inorganic substances (trace metals such as Ag), and biological and microbial (fecal coliform, total coliform, Clostridium perfringens) (Bothner et al., 1994; Eganhouse et al., 1983; Vivian, 1986). Many of these components are of environmental concern, including biodegradable and persistent organics, nutrients, pathogens and trace metals, all of which are commonly associated with sewage particles. The effects of these components are summarized in Table 1.1 (Bishop, 1983). Sewage wastes discharged historically onto Sturgeon Bank from the Iona sewage treatment plant immediately south of Vancouver (Figure 1.1) resulted in severe degradation of an area near the point of discharge. From 1963 when the plant first opened to 1988, when a deep outfall was built, sewage was discharged to a ditch south of the Iona Jetty. The consequently degraded area extended from the Jetty landward to Sea Island and resulted in a drop of dissolved oxygen levels in bottom waters and the death of organisms. Site A O (Figure 1.1) was severely degraded and actually became azooic. High levels of trace metals and organics were and still are found at this site (McGreer, 1982; Pomeroy, 1983). Sturgeon Bank has been closed to clam and oyster harvesting because of high counts of coliform bacteria. From time to time, bacterial contamination has also lead to the closure of beaches in Vancouver. Clearly, identifying the overall distribution and areas of accumulation of sewage wastes in coastal environments is of primary importance, given the potentially harmful 1 Table 1.1 Important contaminants in municipal wastewater (after Bishop, 1983). Contaminants Importance in the marine environment Suspended solids Can lead to development of sludge deposits which may bury benthal organisms; may foul gills and filter-feeding organs; reduces sunlight penetration Biodegradable organics May lead to reduction of dissolved oxygen concentrations, thus eliminating certain marine organisms from the area Pathogens May be transmitted to humans by ingestion of contaminated seafood, or possibly by contact during swimming Nutrients May lead to the heavy growth of planktonic and attached algae, and eventually eutrophication Persistent organics Danger to marine organisms due to bioaccumulation of such toxic organics; possible danger to humans from consumption of contaminated seafood Heavy metals May be toxic to marine life which bioconcentrates heavy metals, or to humans who consume contaminated seafood 2 effects to marine organisms and humans (Capuzzo et al., 1985). For a substance to be a useful tracer of sewage it must meet four criteria: 1) it must be enriched in sewage wastes compared to relatively uncontaminated sediments or in the case of isotopes have a different isotopic signal than the receiving environment; 2) it must be persistent in the environment, degrade slowly, or be diagenetically non-mobile; 3) it must have sewage as its primary anthropogenic source in the area of interest; and 4) there must be a technique available to measure the substance at low concentrations so it can be measured at high dilutions (Vivian, 1978). Even though many substances have been identified and used as tracers, most do not fulfill all of the requirements (Bothner et al., 1994; Eganhouse et al., 1983; Eganhouse et al., 1988; Hatcher et al., 1977; Vivian, 1986; Sanudo-Wilhelmy and Flegal, 1992). Typically, coliform bacteria are used to indentify the presence of sewage wastes in various settings. However, such organisms and also E. coli are not persistent - numbers decrease in seawater and in the presence of toxic components in sewage (Gerba and McLeod, 1976). Thus, bacteria are considered only short term tracers. Spores of the bacteria C. perfringens are more persistent, but their ubiquity reflects inputs from sources other than sewage wastes, including, for example, runoff (Cabelli, 1977). C. perfringens spores are also difficult to count; uncertainty in values reported by Bothner et al. (1994) ranged from ~ 5-60% and were as high as 90% at low levels. Organic components such as coprostanol and LABs (linear alkylbenzenes) have high values in sewage wastes compared to marine sediments and have been used as tracers. LABs are synthetic and consequently their input is unique to wastewaters. In contrast, coprostanol occurs naturally in the fecal matter of marine mammals. In certain areas this source may be significant but generally concentrations in marine sediments are at trace levels. Both these substances are susceptible to degradation in the environment, but they have seen some use to tracing sewage in coastal settings (Venkatesan and Kaplan, 1990; Hatcher and McGillivary, 1979; Eganhouse et al., 1983). Changes in the ratios of the stable isotopes of carbon and nitrogen isotopes have been observed in marine sediments which have received inputs of sewage waste (Sweeney et al., 1980; Sweeney and Kaplan, 1980a; Burnett and Schaeffer, 1980). However, both isotope pairs have similar signals in sewage and terrestrial material, which limits their use in areas where terrestrial detritus is abundant. Furthermore, a variety of chemical, biological and physical processes alters the signals, and thus complicates, the determination of end-member isotope ratios. Despite these constraints, isotope ratios have provided much information on the presence and distribution of sewage wastes in coastal sediments. 3 Trace metals have also been proposed as indicators of sewage. Silver appears to have the most potential because of its low natural abundance in marine sediments compared to other metals. Cu, Pb and Zn for example are enriched approximately 15, 30 and 40-fold in sewage sludge and have significant anthropogenic sources other than sewage wastes in coastal waters such as the atmosphere, mining activities, industrial inputs and runoff (B.C. Environment, 1992). In contrast, silver is enriched about 200 fold in sewage and its main anthropogenic source is the photographic industry (Forstner and Whittmann, 1981; Smith and Carson, 1977). Subsidiary sources of Ag to wastewater include the electroplating and electronic industries. Silver is also persistent in the environment in that it does not degrade. As such the metal meets the first three requirements for a useful tracer. The final criterion is it must be detectable at low levels. One of the objectives of this thesis research was to develop a method to determine low levels of silver in marine sediments in order to fulfill the fourth criterion. Although silver is not subject to degradation per se, it is subject to transformations between solid and dissolved phases, for example by adsorption to particles such as clays, Fe and M n oxides, and organic matter. Metals such as silver may also be incorporated into organic matter or precipitated as sulphides and can be released back to the dissolved phase by the reduction of Fe and Mn oxides, remineralization of organic matter or by the oxidation of sulphides. Consequently an understanding of the biogeochemistry of silver is necessary to evaluate fully its use as a tracer in the marine environment. The first major objective of this study was to determine the distribution of silver in sediments of the Strait of Georgia using a method that could sensitively detect low levels of the metal. Carbon and nitrogen isotope measurements were also made to compare their distribution to Ag and assess their usefulness as secondary indicators of the distribution of sewage particles in the Strait. A second major objective of this work was to identify more general controls on the accumulation and distribution of silver by comparing its distribution to those of a suite of major and minor elements. The project focussed on the area immediately offshore of the Iona Island sewage treatment plant southwest of Vancouver, and in particular on the submarine outfall west of the plant which releases primary-treated sewage to the Strait between 70 and 100 m depth on the foreslope of the Fraser Delta. The study site and outfall location are shown in Figures 1.1 and 1.2. 4 Figure 1.1 Sampling locations in the Strait of Georgia. Cores used in this study are indicated with a box around the label. For other cores only the top sample was used (0-1 cm or 0-2 cm, see Appendix 2). The 59-series cores were collected in 1993 by the Institute of Ocean Sciences. Samples W9, W10, A14a-1, A14b-1, and transects Wl and the BPt and several other samples (Table A2.3, Appendix 2) were collected in 1995 by Simon Fraser University. VG cores were collected in 1994; SG cores and samples AO, KA1, KA2, W6, W7, and W8 from Sturgeon Bank were collected in 1995; and AG cores, HC samples and A14 and BPt-1 were collected in 1996 (Tables A2.1 and A2.2, Appendix 2). Isobaths are in metres. 5 Figure 1.2 Locations of three sampling transects to the south (S) and six transects to the north (N) of the Iona sewage outfall. Sampling sites on Sturgeon Bank are also indicated. Samples along the transects were collected at water depths of approximately 20, 30,40, 50, 70, 90, 110, 130, and 170 m. For transects 3S, 2S, and IS there is no sample from 20 and 40 m depth and for transects 5N and 6N there is an additional sample at 200 m depth. Core VG1 is located west of the diffuser section of the outfall that extends from a water depth of ~ 70 to 105 m depth. Isobaths are in metres. 6 Chapter 2. Environmental Setting and History 2.1 Strait of Georgia The Strait of Georgia is a long (~ 220 km) narrow (~ 28 km on average) semi-enclosed basin located on the southwest coast of British Columbia between the mainland and Vancouver Island (Figure 1.1). Depths in the Strait average ~ 155 m; maximum depths of ~ 420 m occur in the central basin west of Vancouver (Thomson, 1981). The water temperature in the Strait averages ~ 10 °C and salinity at depth ranges from 29-31 throughout the year (Thomson, 1981). Surface salinities are lower and depend upon the amount of freshwater from the Fraser and location relative to the Fraser River plume. Dissolved oxygen throughout the water column ranges from 7.8-6.6 mg/1 (Thomson, 1981). 2.1.1 Circulation Narrow channels to the north and south restrict circulation in the Strait and communication with the open ocean. The circulation in the Strait is basically estuarine. Most freshwater (~ 80%) enters the Strait via the Fraser River (LeBlond et al., 1991) and flows out both to the north and south, mixing with the dense water below and entraining salt into the upper layer. The density difference between the two layers drives the estuarine circulation as denser water flows in at depth to replace salt lost to the layer above. The circulation is then further modified by tides and winds (Dyer, 1973). About 80-90% of the sea water that enters the Georgia Basin flows in at depth through the Juan de Fuca Strait; the rest enters through Johnstone Strait to the north. The saline inflow is restricted by sills at approximately 100 m water depth. The inflow through Juan de Fuca is greatest when a strong density stratification forms in the Strait in the summer when discharge from the Fraser River is high and tidal mixing is low. The stratification, weak tidal mixing, and estuarine circulation promote landward-flowing gravity-currents at depth that reach velocities of 40 cm/s. Cold, salty, oxygen-rich inflow reaches depths of ~ 250-400 m in the Strait at this time (Leblond et al, 1991). In contrast, depths and velocities reached in the winter are only ~ 100-200 m and 10 cm/s. Inflow through Juan de Fuca in the winter is mixed mechanically by tidal currents, and is consequently not as dense as in summer. Thus, it does not sink to the same depths as the gravity currents. Flow in near bottom waters is predominantly to the north along the bottom contours (LeBlond et al., 1991). 7 The hydrology of the Fraser River is dominated by snowmelt during the freshet from May to mid-July. Flows average ~ 4,000 rn^/s but can be as high as 15,000 m^/s. From late fall to early spring flow is generally < ~ 1, 500 m-Vs (Milliman, 1980) and can be as low as 400 m^/s in winter (Environment Canada, 1992). The mean discharge is ~ 2, 700 m^/s. Water from the Fraser River enters the Strait through four channels: the North Arm (5%), Middle Arm (5%), Main Arm (80-85%), and Canoe Pass (5-10%) (Luternauer and Murray, 1973) (Figure 1.1). Water also flowed through McDonald Slough, located between Iona and Sea Islands, before it was closed in 1959 to provide access to Iona Island. Two jetties, the North Arm Jetty and Steveston Jetty, direct flow out of the North Arm and Main Arm respectively. The North Arm Jetty was constructed in 1914-1917 and further extended over the period 1925-1938. Freshwater from the North Arm moves around Point Grey and into Burrard Inlet (Hoos and Packman, 1974). The Steveston Jetty directs water from the Main Arm south into the Strait, but surface currents tend to push the flow back to the north. A third jetty at the river's end, the Iona Jetty, was constructed in 1962 to prevent effluent from the Iona sewage treatment plant from flowing to the north and ending up on populated beaches in the city of Vancouver (GVRD, 1973). Water entering the Strait from the Fraser River tends to move northward along the eastern side of the Strait and exits the Strait to the north or it may flow back to the south. The * northward flowing currents are naturally deflected to the east by the coriolis effect. Winds help to push surface water further north in the winter and to the south in the summer. These influences create a counterclockwise gyre in the middle of the Strait with the strongest currents being northward along the eastern shore (Pharo and Barnes, 1976). Surface water adjacent to Sturgeon Bank appears to flow northward persistently during the summer regardless of tidal phase (Luternauer et al., 1983; Thomson, 1975). 2.1.2 Sedimentation The Fraser River is the principal source of sediments to the Strait of Georgia, delivering 20 million tonnes on average annually of gravel, silt, sand, and clay to the Strait, ~ 80% of which is delivered during the freshet in late spring. The sediment load entering the Strait consists primarily of coarse silt and sand (Milliman, 1980), but in non-freshet conditions silt and clay predominate. The river drains a large catchment basin (233, 000 km2) that contains plutonic, volcanic, metamorphic, and sedimentary rocks and glacial deposits (Luternauer and Murray, 1973). The silt and fine sands are composed primarily of quartz, 8 feldspar, and iron and magnesium minerals such as amphiboles and clay minerals including illite and chlorite. Clay-sized fractions are dominated by clay minerals and micas (Pharo and Barnes, 1976). There are three distinct sediment provinces in the Strait: an area of little deposition to the south, an area of high deposition on the delta and an area of variable sedimentation to the north, where clays accumulate and the sedimentation rates are lower (Pharo and Barnes, 1976). Fine-grained sediments are carried to the west and northwest away from the delta along the axis of the Strait by surface and deep water currents (Pharo, 1972) and are deposited mainly in the central part of the Strait west of the delta. Little of the suspended sediment in the Fraser River plume is carried beyond Texada Island (Luternauer et al., 1983). Most coarse sediment from the Fraser River settles on the delta. 2.2 Sturgeon and Roberts Banks Sturgeon Bank is located north of the Main Arm between the North Arm and Steveston jetties and Roberts Bank is located south of the Main Arm (Figure 1.1). Most sediments on the banks consist of > 90% sand (Luternauer and Murray, 1973; Feeney, 1995). Delta-front sands consist on average of 40% quartz, quartzite, and chert; 11% feldspar; 45% unstable rock fragments (mainly volcanics); and 4% miscellaneous detritus (Luternauer and Murray, 1973). Fine-grained sediment is found further seaward on Roberts Bank than on Sturgeon Bank. Fine-grained sediment is found near shore on Sturgeon Bank (Figure 2.1; Feeney, 1995). Seaward of the delta front at water depths greater than ~ 9 m sediments are finer grained. The sharp transition at this depth from the shallow coarse-grained deposits to fine-grained sediments on the slope suggests that the 9 m contour is the maximum depth of strong turbulence caused by waves and tidal currents. These also control the deposition of finer grained material towards shore, via the tidal lag effect (Brown et al., 1989). Salt marshes occur near the high tide level on Sturgeon and Roberts banks, and are characterized by sedges (Carex sp.) and bullrushes {Scirpus sp.) (McGreer, 1982). Other vegetation on the delta front is sparse and consists mainly of macroalgae (species of Viva undEnteromorpha ; Luternauer and Murray, 1973). 9 Fine silt Medium silt Coarse silt Very fine sand Fine sand Medium sand Grain size stations Sea Carousel stations Steveston Jetty Vancouver International A i r P ° r t Canadian Coast Guard • hovercraft base Strait of Georgia Fraser River Middle Arm -477445 5445525 Figure 2.1 Sediment grain size on Sturgeon Bank using Wentworth classification (Feeney, 1995). 10 2.3 The Iona Sewage Treatment Facility 2.3.1 History The first sewers were built in Vancouver in 1887 (GVRD, 1988) and conveyed raw sewage directly to Burrard Inlet. Sewage treatment began in 1959 and 1963 on the North Shore and Burrard Peninsula respectively after the Rawn report of 1953 outlined the need. Vancouver has four sewage treatment plants that provide primary treatment for about 98% of all the waste collected by the Vancouver regional sewer system. The Iona plant treats combined sewage (municipal and industrial waste and runoff) from the city of Vancouver, U B C , a small portion of Burnaby, Richmond (Twigg/Mitchell Islands) and Vancouver International Airport. Lions Gate (1959), near the mouth of the Capilano River, primary-treats waste from the North Shore which is then discharged into Burrard Inlet. The Lulu and Annacis islands plants started operation in 1972 and 1975, respectively. The Lulu Island facility treats wastewater from the western portion of Richmond, while the Annacis Island plant treats wastewater from most of Burnaby, New Westminister, Port Moody, Port Coquitlam, Coquitlam, Pitt Meadows, Maple Ridge, a major part of Surrey, a portion of Delta and the city of Langley. Following primary treatment, the effluents from these two plants are discharged into the Fraser River (GVRD, 1992). The Iona Island sewage treatment facility commenced operation in 1963 and was expanded in 1973 and 1982. Until 1988, primary-treated waste from the plant was released into a 1 to 3 m deep open channel that ran along the south side of the Iona Jetty. The channel was exposed during low tide and covered during high tide. A deep outfall (described in Section 2.3.3) was installed in 1988, and sewage has since been discharged into the Strait of Georgia through diffusers that rest on the foreslope of the Fraser Delta between about 70 and 105 m depth. The discharge from the Iona plant averages 14 m^/s and represents the largest point source input of wastes into the Fraser River estuary (Churchland et al., 1982). The influent to the Iona plant is largely derived from domestic activities and storm sewers. The industrial component represents only ~ 7% by volume (Rogers et al., 1986) which originates from a variety of industries including food processing (~ 40%), wood processing (~ 16%), the metal, chemical and plastics industries (~ 25%), and photographic processing (~ 10%). 11 2.3.2 Treatment Sewage treatment can include three stages: primary, secondary and tertiary. Of these primary involves the removal of solids through screening and sedimentation, secondary involves reducing the biological oxygen demand (BOD) of primary-treated effluent via the bacterial degradation of the organic matter (Mueller and Anderson, 1983) and tertiary is designed to remove specific components such as nutrients (N and P), trace metals and organic compounds (Mueller and Anderson, 1983; Vesilind et al., 1994). Generally, primary treatment is used for sewage wastes disposed into the marine environment and secondary treatment for sewage disposed into rivers and/or lakes; tertiary treatment is employed in many environmentally-sensitive areas. At the Iona plant primary treatment is used to reduce the suspended solids by about 50% and the BOD by about 40% (GVRD, 1993b). The yearly average suspended solids in the influent and effluent are 143 mg/L and 77 mg/L and the BOD 150 mg/L and 91 mg/L, respectively (GVRD, 1994). There are three steps involved in removing solids from raw sewage at Iona: screening, aeration and sedimentation. In the first, the raw sewage is passed through a screen with spacings of 2.5 cm to remove objects such as wood, rocks and rags. These screenings are ground up into small particles and returned to the influent flow after the screening step. Pieces that can not be ground up are taken to a landfill. In the second step, small dense particles such as sand and coffee grounds are removed in grit chambers. These particles have relatively high settling velocities and do not degrade well (Manahan, 1991). Removing the grit reduces the clogging of pipes and protects moving parts from abrasion and wear (Manahan, 1991). The grit is removed and taken to a landfill (GVRD, 1989b; G V R D , 1993b). The effluent is discharged back into the influent channel. In the third step, suspended particles that are mainly organic are allowed to settle out in a sedimentation tank. The settled material, called sludge, is removed and then thickened and pumped to a digester. Floatable materials like grease, oil, plastics and soap are raked off the top of the sedimentation tank and added to the digester (GVRD, 1989b; G V R D , 1993b). Sludge is treated by stabilizing it to reduce or remove its odor and potentially harmful pathogens and to remove water to make its disposal easier and cheaper (Vesilind et al., 1994). Sludge is generally enriched in materials associated with particles such as toxic organics, metals and microorganisms (Capuzzo et al., 1985; Vesilind et al., 1994). There is no effective method available for removing heavy metals, pesticides, and other potential toxins from the sludge. 12 Sludge is anaerobically digested in heated tanks. Under these conditions, volatile organics and other organic material are degraded by bacteria into gaseous products, mainly methane, carbon dioxide and trace amounts of hydrogen and hydrogen sulphide. Odor and putrescence of the sludge is minimized, pathogens are destroyed and the volume is reduced in anaerobic digestion. It should be noted that not all sewage always receives primary treatment at Iona. Untreated sewage is occasionally discharged through the old channel onto Sturgeon Bank during periods of heavy rainfall and high runoff. At such times, the plant cannot cope with the volume and is forced to divert some of the flow onto the bank. 2.3.3 Disposal As noted earlier, treated effluent from the Iona plant is discharged into the Strait of Georgia from a deep sea outfall, which consists of two pipes side by side that extend due west approximately 7.7 km offshore (GVRD, 1989b). The last 500 m of both pipes contain multiport diffusers that are initially about 6 m apart that separate to form a Y shape. At their ends, the diffuser sections are about 10 m apart. The pipes are perpendicular to the predominantly northerly currents along the foreslope (Thomson, 1975) which is the recommended configuration for areas where currents are predominantly in one direction (Mearns, 1981). The Iona diffuser section extends from water depths of ~ 70 to 105 m (GVRD, 1989a). Diffuser outfalls are designed to mix the effluent with seawater at a ratio of about 1:100. Typical "initial" dilutions of 1:80 to 1:300 are obtained depending on current velocity and direction, flow rate of the effluent, and density of the effluent and seawater (Preston, 1975), and dilutions of 1:130 and 1:275 for the Iona outfall have been determined (GVRD, 1989b). 2.3.4 Plume Dispersion Effluent discharged from outfalls rises in saline water columns where it contains mostly fresh water and is therefore less dense. As such plumes rise they can be dispersed laterally by diffusion and advection (Preston, 1975). Plumes will rise until a level of neutral buoyancy is reached (Preston, 1975; Bishop, 1983). The height to which the plume rises depends upon the density of the wastewater and seawater, the degree of mixing as the wastewater rises in the water column, and the presence of a pycnocline. Figure 2.2 illustrates the dispersion of a sewage plume from an outfall in the absence of a pycnocline (a) and in the 13 a) No pycnocline b) Pycnocline u = 0 small u large u u —« Figure 2.2a) Effluent plume dispersion from an outfall in the ahspnrp nf a n i m i n , i • in the presence of a pycnocline under different currem ^ u S ^ K o h , ^ 1 1 1 1 6 ^ b ) 14 presence of a pycnocline (b) at zero current velocity (u), low current velocity and high current velocity. An effluent plume will generally remain trapped below the pycnocline and be dispersed horizontally, through advective and diffusive processes resulting from waves, tides and currents. The pycnocline in the Strait of Georgia generally sits between 30 and 50 m water depth (Thomson, 1981; Hoos and Packman, 1974). Iona effluent has been traced offshore by adding a Rhodamine WT fluorescent dye on two days under different tidal conditions (GVRD, 1989b). The plume travelled north, parallel to the bottom contours, during both flood and ebb tide conditions (Figure 2.3). The plume was approximately 40 m thick and trapped 30 m or deeper below the surface. This observation is consistent with trapping of the plume below the pycnocline. Multiple plumes resulting from the discharge of the effluent from the outfall at varying depths along the length of the diffuser section were also observed. The plume width laterally was < 1000 m, on average, and moved north at an average speed of 20 cm/s. Final dilutions observed in the ~ 8 hr test runs were 1:1300 and 1:2600. A later study also found that the plume remained ~ 25 m below the surface and that it came in contact with the bottom sediments (Bertold and Stewart, written communication, 1996). The presence of the plume in the water column was determined by high fecal coliform counts. It was also observed that the plume stayed within a narrow strip along the foreslope which could be defined ~ 7 km to the north and 4 km to the south of the diffuser. Sewage particles are mostly 1-10 p:m in size and include clay, organic matter, and hydroxides (Postma, 1980). These finer particles tend to settle in quiescent areas (NRC, 1984). Determining where they end up is important because they contain most of the pathogens, trace metals, and persistent trace organic compounds (NRC, 1984). Sewage particles with settling velocities of 0.01 cm/s or faster (O'Connor et al., 1985) create zones of deposition near diffusers that are generally elliptical or oval in shape (e.g., Figure 2.4). The centre of the pattern generally occurs several km upcoast or downcoast but rarely at the diffusers (Mearns, 1981). Approximately < 10% of effluent particles create these zones (Galloway, 1979) and the remaining fine particulate matter presumably remains suspended in the water column and is dispersed further by turbulence and currents (Mearns, 1981; Vaccaro, etal., 1981). 15 UEJRE5 m | o r e » 2 " 3 D i s t r i b u t i o n P a t t e r n o f I o n a s e w a g e plume as indicated by a dye tracer (GVRD, 16 PALOS VERDES PENINSULA i < i » > \ « BASELINE:ro 43 PPM-ORY WEIGHT 250 Figure 2.4 Contour pattern of trace metals in sediments near a California outfall as indicated by zinc isopleths in ppm (Hershelman et al., 1981). 17 Chapter 3. Sewage Tracers Many biological and inorganic materials have been used in the past to trace sewage discharged to coastal waters. These will be briefly reviewed in this chapter to provide some comparative context for the later focus on silver. 3.1 Coliform Bacteria and C. perfringens In the early 1900s, bacteria associated with the fecal wastes of warm-blooded animals were the first indicators used to identify waters contaminated by sewage. Coliform bacteria and more rarely Clostridium perfringens were used to index the health quality of drinking and recreational waters. C.perfringens was rarely used because an easy method of measurement was unavailable and the survival of the spores relative to the bacteria caused concern with respect to its usefulness as an indicator (Cabelli and Pedersen, 1982). Coliform bacteria are defined as all the aerobic and facultative anaerobic gram-negative, non-spore forming, rod-shaped bacteria that ferment lactose and produce gas within 48 hours at 35 °C (Mack, 1977). Clostridium perfringens are obligatory anaerobic, spore forming bacteria that are consistently found in the feces of humans and other warm-blooded animals (Cabelli and Pedersen, 1982). The short residence time of coliform bacteria and C. perfringens in the environment, 2-3 weeks, and the presence of some coliform bacteria naturally in waters reduces the potential of these indicators to determine water quality and the extent of sewage contamination (Vivian, 1986). Escherichia coli is a permanent resident in the gastrointestinal tract of humans and animals and one of the dominant organisms isolated in feces, and it is sometimes used in conjuction with the total coliform, to identify sewage contaminated waters and sediments Ayres (1977). Spores of C. perfringens are considered a useful tracer because unlike the bacterium itself, they are resistant to degradation, chlorination, heat and toxic chemicals. As a result C. perfingens spores have been used to monitor sewage particulate deposition and movement (Cabelli and Pedersen, 1982). Spores of C. perfringens are especially useful tracers in areas of remote or intermittent sewage inputs and of sewage that has been chlorinated or contains toxic chemicals that reduce the numbers of E. coli (Cabelli, 1977). However, the stability of the spores makes them ubiquitous in nature, and it is sometimes difficult to identify their source in coastal environments (Cabelli, 1977). 18 3.2 Coprostanol Coprostanol or 5B-cholestan-3B-ol, is one of the dominant sterols in human feces and was first isolated in 1862 (Hatcher et a l , 1977; Singley et al., 1974). The compound is formed by the reduction of cholesterol by enteric bacteria in the large intestine (Rosenfeld et al., 1954). Coprostanol is considered to be an excellent marker to define areas influenced by sewage contamination (Holm and Windsor, 1990). The long-standing and widespread use of this sterol as a tracer of sewage sludge or effluent is due to its abundance in human feces and its absence or trace concentration in non-contaminated sediments (Vivian, 1986; Eganhouse et al., 1988). Table 3.1 lists the concentrations of coprostanol in such materials from various locations. Coprostanol is only slightly soluble in water and is usually present in association with particulate material (Hatcher and McGillivary, 1979). Primary treatment and more significantly, secondary treatment of sewage reduces the concentration of coprostanol, due to its association with removed solids, as well as degradation. Coprostanol is not affected by chlorination, heat or toxic industrial discharges but it does appear to undergo aerobic degradation in the water column. Coprostanol is more stable in sediments, and in anaerobic sediments degradation occurs slowly or not at all (Walker et al., 1982). Coprostanol formation may occur in sediments by the reduction of cholesterol, but this source seems to be minor. Marine sediments incubated over 1-3 months with bacteria that occur naturally in sewage and natural waters converted only 0.5% of cholesterol to the reduced products, 5-alpha stanols and 5-beta stanols (Walker et al., 1982). Although this source appears to be minor it should be considered along with aerobic degradation when coprostanol is used as a sewage tracer. One other caveat bears mention. Fecal matter from marine mammals may be a significant source of coprostanol. Venkatesan et al. (1986) found levels of coprostanol in Antarctic sediments similar to those found at depth in a sediment core from the contaminated New York Bight, described by Bothner et al. (1994). The most likely source of the coprostanol in the Antarctic sediments is excrement from whales. Venkatesan and Kaplan (1990) suggested that the ratio of coprostanol to epicoprostanol can be used to differentiate between human and other mammalian feces in order to correct for the presence of coprostanol levels naturally present in marine sediments. 19 Table 3.1 Coprostanol concentrations in sewage effluent, sewage sludge, sewage contaminated sediments and relatively uncontaminated sediments from various locations. Values are in ppm. Note that the analytical detection limit for this compound is very low, which improves its utility as a tracer. Location Effluent Particles Sludge Trap Samples Sediments Background U . K . 1 5.84 13.58 0.003-0.12 Florida^ < 0.010-2.5 California^ 29-140 947-1374 1.5-5.1 New Y o r k 4 1,960-3,300 175-920 0.009-0.823 0.012 1- Goodfellow et al., 1977 2- Holm and Windsor, 1990 3- Venkatesan and Kaplan, 1980 4- Bothner et al., 1994 20 3.3 Linear Alkylbenzenes Eganhouse and Kaplan (1982) identified a homologous series of long-chained alkylbenzenes (LABs) in municipal wastewaters from southern California. The compounds seemed to be abundant and ubiquitous constituents of domestic wastewater and appeared to be potential tracers of waste in the marine environment. Because these compounds do not occur naturally, (they are derived from detergents) their presence in the environment can be taken as unequivocal evidence of anthropogenic waste contamination (Eganhouse, 1986). Despite susceptibility to aerobic degradation, LABs are a major component of municipal wastewaters (Eganhouse and Kaplan, 1982). About 97% of LABs.are removed by both primary and secondary sewage treatment due to both biodegradation and solids removal (Takada and Ishiwatari, 1987), but some LABs survive such treatments and are preserved in sewage-bearing sediments for at least 10-20 years (Eganhouse et al., 1983). Typical concentrations of LABs in sewage effluent and sludge and sewage contaminated sediments are listed in Table 3.2. 3.4 Osmium Isotopes Osmium has several natural isotopes but only two have been used as potential tracers of sewage, 187os and 1860s. The heavier isotope 187()s is produced from the [3-decay of 187R e. The ratio of 187Re/186os is relatively high in the crust and the l 8 7 o s / 1 8 o O s ratio is similarly high (~ 10 to 11). Since seawater derives most of its Os from weathering of the crust, the l ^ O s / l S o o s ratio is about 8.6 in the ocean. Unpolluted sediments near large rivers have a ratio between the two values (Esser and Turekian, 1993). Industrial Os is mined from ore deposits with low l 8 7 R e / 1 8 6 Q s r a t ios and consequently lower 187os/186qs ratios (~ 1). Osmium has several industrial and research uses which include tissue staining for electron microscopy and use as a catalyst in the synthesis of steroids. Osmium is recovered in steroid synthesis but not in microscopy, and consequently may enter the sewage system from this source. Because industrial Os has a significantly different isotopic signal from Os in marine sediments, the Os isotopic ratio may potentially be used to trace sewage (Esser and Turekian, 1993; Ravizza and Bothner, 1996). 21 Table 3.2 Linear alkylbenzene concentrations in sewage effluent, sewage sludge, sewage contaminated sediments and relatively uncontaminated sediments from various locations. Concentrations are in ppm. As for coprostanol, the sensitive detection limit makes L A B s a valuable tracer. Location Effluent particles Sludge Trap samples Sediment Sediment Background Australia 1 0-19 North Sea 2 2.8-84.8 U . K . 2 0.10-2.3 California 3 1,342 34 217-302* New Y o r k 4 90-213 0.300-112 0.001-0.197 0.0008 1- Murray et al., 1987 2- Raymundo and Preston, 1992 3- Eganhouse et al., 1983; *Chalaux et al., 1992 4- Bothner et al., 1994 22 3.5 Carbon and Nitrogen Isotopes 3.5.1 Carbon Isotopes Marine and terrestrial organic matter b^C isotopic signals differ by about 8%c. Marine and terrestrial end-members are now typically assigned 8 l 3 C values of -19%o and -27%o (Sackett, 1989). This difference is primarily due to the difference in the isotopic signal of the carbon source fixed by marine and terrestrial plants. Carbon dioxide fixed by terrestrial plants has a 8 l 3 C of ~ -7.8%o. Dissolved CO2, HCO3" and CO3" in the ocean fixed by marine plants has a S ^ C of ~ 0%c, approximately 8%o heavier than atmospheric CO2. Plants discriminate against the heavier isotope during carbon fixation and consequently the b^C of the synthesized organic material is much lower than the carbon source, by approximately 20%o. Two different metabolic pathways are used to fix carbon: one, the C3 pathway, uses the enzyme RuBP carboxylase; the other, the C4 pathway, uses PEP carboxylase (Lajtha and Marshall, 1994). Most terrestrial plants including trees, shrubs, herbs, some grasses, rice, wheat and barley use the C3 (Calvin cycle) pathway. This is the dominant pathway of carbon fixation in temperate latitudes and for phytoplankton. Terrestrial C3 plants have an average 8 l 3 C value of - 27%o and phytoplankton, ~ -20%o. Table 3.3 lists the 8 i 3 C values for a variety of C3 plants. Plants adapted to warm and dry habitats, such as some grasses and corn, use the C4 (Hatch-Slack cycle) pathway, whereby CO2 is converted to a 4-carbon product by the phosphoenolpyruvate (PEP) carboxylase enzyme. Fractionation during carbon fixation is less than for C3 plants. Values for terrestrial C4 plants are around -14%o (Rundel et al., 1988). C A M (Crassulacean Acid Metabolism) plants use both pathways. Carbon dioxide is fixed by PEP carboxylase at night and by Rubisco during the day. C A M plants have S ^ C values that range over C3 and C4 values (Figure 3.1). Factors such as water temperature, the concentration of dissolved inorganic carbon in the ocean, species and growth rate affect the 8 l 3 C value of phytoplankton. However, much of the variability in the 8 of bulk plankton on an ocean-wide basis can be explained by ambient [CC»2(aq)] and related phytoplankton CO2 demand (Rau, 1994). Rau et al. (1992) found that 8 of suspended organic matter in the North Atlantic during a phytoplankton bloom became isotopically heavier from -22.9%o to -18.1%o in ~ 5 weeks as [CO2 (aq)] decreased. The 8^ 3C of the particulate organic matter was negatively correlated to the concentration of dissolved CO2 (Figure 3.2). 23 Table 3.3 Values of 8 1 3 C in C3 plants (Lajtha and Michener, 1994; Simenstad and Wissmar, 1985*). Organic Material C3 (trees, shrubs, herbs, grasses) Terrestrial (average) -26.5 Terrestrial (range) -23 to -30 Marsh plants -23 to -26 Benthic algae -10 to -20 Marine -18 to-24 phytoplankton Sea lettuce* {Viva -10.5 lactuca) Enteromorpha* -17.5 24 30 20 10 30 20 10 c: 120 w = 110 a> iT 1 0 0 90 BO 70 60 50 40 30 20 10 0 C. Known CAM ptantt B . -30 -20 -10 L Known Cj ptonti Known C4 planttJ ^ 4 -30 -20 -10 A . -30 -20 •10 3 10 0 10 0 10 0 20 10 0 10 H . Mann* Plankton o. -30 -20 -10 Lacustrine ptantt •xelvtiva of plankton r -J»- f l jT l^fMTI n rj F. Marina planti atelutiva of plankton fTh r h rii-i h E . Aquatic plants n . rrnnrlmlllTlTk^  Alaaa -30 -20 1 -10 Figure 3.1 Values of 8 1 3 C for C3, C4, and C A M photosynthetic pathway plants (Rundel et al., 1988). 25 Figure 3.2 Changes in the S ^ c of (a) particulate inorganic carbon (PIC) and (b) suspended or sinking particulate organic matter (POM) from JGOFS's North Atlantic Bloom Experiment Site, April 25-May 31, 1989 (c) changes in ocean mixed layer [TC02] and [C02(aq)J at the same location and time period (Rau et al., 1992). 26 Similarly, Rau et al. (1991) observed a decrease in the 8 i 3 C of organic matter near Antarctica from -23.2%o to -30.3%o that correlated with a decrease in water temperature and a consequent increase in the (calculated) dissolved CO2 (Figure 3.3). At lower temperatures more CO2 dissolves. The increase in dissolved CO2 could account for the lighter signal found for plankton since an abundant supply of dissolved CO2 allows for substantial discrimination against l ^ C isotope by phytoplankton. In estuarine environments there are many sources of organic matter with a variety of 8 l ^ C values, including riverborne terrestrial organic material, salt-marsh macrophytes, phytoplankton, seagrasses and benthic algae. As a result the 8 l 3 C value of organic matter in estuarine environments can vary significantly. However, values of carbon isotopes in estuarine sediments indicate that most particulate organic matter usually originates from terrestrial organic matter and phytoplankton rather than eelgrass or macroalgae beds (Simenstad and Wissmar, 1985). The relative importance of the two depends upon location within the estuary and hydrodynamics. Offshore, phytoplankton dominate and nearshore benthic algae and seagrasses are more significant sources. Seagrasses, macroalgae and C4 marsh plants are not usually major contributors to estuarine particulate organic matter except on the fringes of estuaries (Simenstad and Wissmar, 1985). Finally, fractionation of S l^C up the food chain is minor (< \%c). Values in consumer organisms and sediments are similar to 8* 3 C values of the primary producer (Lajtha and Michener, 1994); transfer of carbon isotope ratios is essentially conservative between trophic levels. 3.5.2 Nitrogen Isotopes With respect to S l ^ N , marine sedimentary organic matter is isotopically heavier than terrestrial organic matter, general values being approximately 5-6%o and 0-4%o, respectively. As in the case with carbon isotopes, the S ^ N value of primary producers depends upon the isotopic signal of the source nitrogen. In contrast to carbon isotopes, there are no different fractionation pathways. In fact, there is little fractionation during nitrogen fixation and nitrogen fixing plants have 8 ^ N values close to that of atmospheric nitrogen, ~ 0%c. Non-fixing plants have higher 8 ^ N values of ~ 4%o (Lajtha and Michener, 1994). This is due to the uptake of nitrogen from the soil which has a heavier S ^ N than air. Animal waste is a likely cause of heavy S ^ N values in soil. Unlike 8 l 3 C , S ^ N increases along the 27 o o CO r -o CO o Q. -22 -24 -26 -28 i -30 =32 y = - 29.133 + 0.61607X RA2 = 0.915 * J * © V © • March 3-7 Q March 27-31 -22 -24 -26 -28 -30 -2 0 2 4 6 8 10 12 Surface Water Temperature (degrees C.) -32 y = - 9.3996 - 0.89857x~: ^ „ • RA2 = 0.907 r 0 X o B 1 4 1 6 1 8 20 22 24 Surface Water [C02(aq)] (uM @ atmospheric equilibr.) Figure 3.3 P O M S ^ C versus (a) surface water temperature and (b) surface water [C02(aq)] at atmospheric equilibrium (Rau et al., 1991). 28 food chain, about 3%o per trophic level (Altabet and Small, 1990; Minagawa and Wada, 1984; Rau, 1981). Consumers preferentially retain the heavier isotope and excrete isotopically light waste products. Thus terrestrial organic materials have 8 ^ N values ranging up to 4%o higher than atmospheric nitrogen. The average is ~ 2.5%o (Lajtha and Michener, 1994). Peters et al. (1978) found that riverine terrestrial material derived from agricultural areas was isotopically heavier than that found in rivers draining uncultivated soils. This may reflect the loss of isotopically light ammonia gas during the hydrolysis of urea in animal waste, as fertilizer-N generally has a value close to 0%o. A complicating factor is that sub-surface soil horizons containing residual fertilizer-N often exhibit low values (-2.2%o). Thus cultivated soils may either be isotopically heavy or light and this may further extend the range of terrestrial 8 A ^ N values observed in suspended particulates in rivers, such as the Fraser, that pass through farming regions. Phytoplankton assimilate nitrogen primarily as NO3" but also N02", NH4+ and urea. The 8*5n of nitrate in the ocean is typically ~ 3-6%o, but may reach up to extremes of 18%o. Nitrate increases when phytoplankton take up l ^ N preferentially and where denitrification occurs; both processes leave residual NO3" enriched in the heavier isotope. Phytoplankton in areas where denitrification is prevalent often exhibit S^n values as heavy as 12%o, reflecting their incorporation of heavy residual NO3" in these areas. On the global scale, denitrification is considered to be the underlying factor for the enrichment of l ^ N in the ocean relative to the atmosphere, since denitrification is the only process that causes a preferential loss of 1 ^-depleted nitrogen (as N2) from the ocean. In the presence of high concentrations of nitrate, phytoplankton preferentially take up 14 N . As more of the lighter isotope is removed, the remaining dissolved nitrate pool becomes enriched in the heavier isotope. At low concentrations of nitrate in the water, phytoplankton utilize both the l ^ N and 15]sj nitrate and consequently have heavier 8 ^ N values (Altabet and Francois, 1994) as illustrated in Figure 3.4. Particulate organic matter S ^ N increases with depth in the water column, which is attributed to two factors: release of isotopically light degradation products as organic matter degrades, and the accumulation of the heavier isotope by organisms from their food (Saino and Hattori, 1980). For example the average S ^ N for phytoplankton is ~ 7%o, for zooplankton ~ 10%o, and fish ~ 15%o (Sweeney and Kaplan, 1980b). Figure 3.5 shows for a given ecosystem S ^ N values increase from phytoplankton to zooplankton to fish. Although it has been documented that residual S ^ N increases during the degradation of organic material and associated release of isotopically light products in water columns, 29 oT * c O) •B- 3 n o h | 2 o § 1 O 0 I • • • • • 24/4 28/4 2/5 6/5 10/5 14/5 18/5 22/5 6 Z X surface suspended PN C» av. in upoer 50 m • 80-m sediment X trao *4 24/4 28V4 2/5 6/5 10/5 14/5 18V5 22/5 Date (day) Figure 3.4a) Reduction of N 0 3 ' concentrations with time and b) increase in 8 1 5 N values of surface suspended particles (Altabet et al., 1991). These data were collected during the course of a phytoplankton bloom in the North Atlantic. 30 5 10 15 East On no Sea f*ytooian«ton Mixec piankton Zoopankton 3enna Sea F*ytociankton Zoocxankton Pisn Lake Aaninoko Phytooiankton Zoocxankton Fisn to no so poody ficia LMI hocoer Soider Tree frog Figure 3.5 The 5 1 5 N of animals collected from marine, freshwater, and land ecosystems (Minagawa and Wada, 1984). 31 studies indicate that the 8 ^ N of particulate nitrogen does not appear to change significantly in sediments during diagenesis. Released N H 4 + does get lighter with increasing burial and solid phase S^n values become slightly heavier, but such changes are considered to be insignificant (Velinsky et al., 1991). 3.5.3 Carbon and Nitrogen Isotopes as Sewage Tracers Carbon and nitrogen isotopes have been frequently used to determine the source of organic material to marine sediments as being either marine or terrestrial. Sackett and Thompson (1963), for example, showed a systematic variation of sedimentary 8 l 3 c values seaward from river mouths. The variation resulted from the mixing of river and marine-derived organic material. Values from river sediments ranged in the Sackett and Thompson report from ~ -28.3%o to -24.3%o and in open marine settings from -19%o to -2l%o. Carbon isotope measurements have also been used in the identification of the fate and distribution of sewage wastes in coastal environments (Hunt et al., 1992; Burnett and Schaeffer, 1980; Sweeney and Kaplan, 1980a; Sweeney et al., 1980). This application is based on the fact that the isotopic signal of sewage is distinct from the marine isotopic signal. However, as can be seen in Table 3.3, the isotopic signal of sewage is often not much different to that of terrestrial material. Thus, the use of 8 i 3 c as a sewage tracer is limited (Owens and Law, 1989; Thornton and McManus, 1994). Nitrogen isotope ratios in sewage effluent are typically 2-3%o (Table 3.4) and in marine sediments 4-10%. Sweeney et al. (1980) used a two end member mixing model to identify sediments contaminated by sewage. Surface sediment 8 X ^ N values ranged from 1.8%o to 10.6%o. Sediments with a 8 1 5 N of 1.8%o to 3.6%0 were considered to be the most contaminated. 8 a ^n values in sediments were lower in the middle of transects near the outfalls from ~1.8%o to 4.6%o with the lowest values closer to the outfalls. Values increase towards land and the ocean to ~5%o to 9%o. However there are no major rivers located near this site (Sweeney et al., 1980). Burnett and Schaeffer (1980) reported lower 8 ^ C values in sediments from the New York Bight dumpsite (-26.2%o) compared to sediments away from the site (-22.0%o). Sludges had a 8 l 3 c value of ~-25.7%o and -26.0%c. A distinct pattern at the site of the sludge dumpsite (Figure 3.6) indicates 8 i 3 C values are potentially useful as a quantitative tracer for sludge in coastal marine environments (Burnett and Schaeffer, 1980). Similar to the study in California terrestrial inputs into the area were considered to be small. 32 o c a Vi 0) 3 > •c & E a D •o Z c >n - To is ,,—N °C o3 fa of _c 'C E _c m To T3 c U co To c/3 3 > C O IS JReference | Owens and Law, 1989 (estuarine) Thornton and McManus, 1994 (estuarine) Williams et al., 1992 Van Dover etal., 1992 Hunt el al., 1992 Sweeney and Kaplan, 1980a Sweeney and Kaplan, 1980b; Sweeney et al., 1980 Peters et al., 1978 | Sewage >n CM CN| — i i © 7 rn CO CM CO* in cm' CM co Terrestrial CO CN On CM cm' r^" | Marine <N tt ' O ; in in 30* o 1—1 30 u C O To a" 00 O vo E22 cm ON ^22 o O SO CM CM CM CM O ON 22 cs r-CM CM CO CM B ON 2 ON r—t ON CN S"3 CM r-- r-^  CO Tf' CO CM CM CM CM |CM 5 ON s 2 CO CM P o3 © S J3 0O ,5 U ON PS GO ~ CM CM O CM CM £2 m CM , i n co CM CM 33 a u 73«58'W 54' 50* 46" Distance (deg wast) M M 73*22' 40°34'N TV/V^ -HSV53J —t 1 —i K / V ^ -28' . 22' Distance (deg north) 40«00' Figure 3.6a) Profile of 8 l3c values of an east-west transect through the New York Bight and b) a north-south transect profile (Burnett and Schaeffer, 1980). 34 3.6 Silver Silver is a scarce constituent in marine sediments: concentrations in uncontaminated deposits are typically 0.1 ug/g (Koide et al., 1986), while the value recommended for 'average shale' is 0.07 ug/g (Bowen, 1966). However, high levels of silver are typically measured in sediments near sewage outfalls and sludge-dumping sites (MacKay et a l , 1972; Papakostidis et al., 1975; Amiel and Navrot, 1978; Bruland et al., 1974; Hershelman et al., 1981; Phillips and Hershelman, 1996; Bloom and Crecelius, 1987; Chapman et al., 1996; McGreer, 1982). The contrast between pristine and contaminated sites can be profound, which reflects the fact that in sewage, silver routinely has the highest average enrichment factor (EF=concentration in waste/average crustal concentration) of any metal (see Tables 3.5 and 3.6). Given its significant enrichment in sewage, the absence of competing sources other than sewage, its low crustal abundance, and its persistence in the environment (a metal does not degrade), silver meets all the criteria for an ideal sewage tracer. Silver has been shown to correlate with other sewage tracers in the New York Bight sediments (Figure 3.7; Bothner et al., 1994). The sole constraint in its application is analytical sensitivity, but relatively new methods and instrumentation have largely eliminated this concern. In the following sections, the marine and sedimentary chemistry of silver will be reviewed briefly, in order to establish the context for the interpretation offered in Chapter Five of the distribution of silver in southeastern Georgia Strait. 3.6.1 General Chemistry and Speciation Silver is a B-type metal with a single s-electron outside a full d-shell. It has the potential to form a cation with more than one charge but in aqueous environments only the +1 oxidation state occurs. The cation forms stable complexes with B-type ligands in the following order of decreasing stability: S >I >Br >C1 >N >0 >F. In oxic seawater the most abundant ligand is chloride and consequently silver exists as mainly as chloride complexes. However in reducing environments Ag has the tendency to form insoluble sulphides and sulphide complexes (e.g. AgSH, Ag(SH)2" Ag2S3H2" 2) with S~2 and HS~. Traces of sulphide readily displace OH and CI groups (Stumm and Morgan, 1981). Ag2S, the least soluble solid form of silver, is formed when sulphide ion or hydrogen sulphide are mixed into silver-bearing solutions (Table 3.7a). Mercury is the only metal to form a more insoluble sulphide than Ag of those listed in Table 3.7b. There are two natural isotopes of silver that occur in almost equal abundance: 35 Table 3.5 Metal concentrations and enrichments in sewage sludge and sewage particles. Metal concentrations are in ppm. Enrichment factors are the ratio of the metal concentration in the sewage waste divided by the metal concentration in uncontaminated sediments or average shale. Average shale values from Bowen (1966). Sewage Sudge1 U K Sludge2 Kuwait Sludge3 California Waste Particles^ JWPCP Hyperion Ag Cone Bkg EF 20 0.1 200 - 35 0.07 500 32 0.61 52 130 0.71 183 Cu Cone Bkg EF 700 45 15 370 37 10 270 55 5 1,120 21 53 1,500 13 115 Pb Cone Bkg EF 450 15 30 771 86 9 300 12 25 570 6.2 92 320 6.9 46 Zn Cone Bkg EF 2600 65 40 1125 165 6.8 3000 70 43 4,100 75 55 2,300 57 40 1- Forstner and Whittmann, 1981 2- Lester et al., 1983 3- Samhan and Ghobrial, 1987 4- Galloway, 1979 36 c o J c •c.S C T 3 en C " ° • s i Average EF 23.1 00 so «/> St. of Georgia (This 31UUV 1 0.850 0.07 12 <n >o ^ 15.6 20 0.78 — Q\ H Sturgeon Bank (This study) 1.303 0.07 18 IT, o m . " ON *H c o oc ^ =3 c oo CQ r-n <=> n M o m —' r*> <N O 00 C-J T f O N SO IT, — O N in T3 4) C 00 3 = O Cu 00 0.573 0.056 11 56.6 30.6 1.9 43.8 7.2 6.1 California Los Angeles^ ^ <N ^ —< oo O ~t t> —i SO mm 1*; 1 -D 0.2-5 0.2 22 38-208 5.3 6 O cn so r> oo rr 136-826 165 5 Athens2 0.04-2.7 0.07 39 45-1800 95 19 a! oo 8.0-25.3 45 0.56 83-221 20 11 s Metal < U CO W ( - g j^fc, "1 _ oJ.2 M c — « >..s *>i- O " U T ^ -c .1 « o M ^ g*« » < a. 2 ac • i i i oo O N o 4> <N r*-! 00 U Os TO D E 2 0 o 1 I IT , V O 37 300-250-a 200-I 150-1 §• 100-1 u 50-0-120 100-1 • A • o o • a S • • • A • 1 8 10 12 14 16 10 O u 16 •10 -e 2 9 -6 S o a. •« 5 1 0 -0.01 Ag (jig/g) Figure 3.7 Relationship between Ag and coprostanol (unfilled circles), L A B s (triangles), Corg (filled circles), and spores of Clostridium perfringens (squares) in sediment trap samples from the New York Bight (Bothner et al., 1994). 38 Table 3.7 Solubility constants for a) Ag compounds; and b) metal sulphides (Jenne et al., 1978; Krauskopf, 1979). a) Compound Solubility constant (Ksp) Ag20 12.56 AgOH 11.93 AgF 0.55 AgN03 0.13 Ag2S04 -4.92 AgCl -9.75 Ag2C03 -11.07 AgBr -12.27 Ag -13.51 A g 3 P 0 4 -15.98 A g l -16.07 Ag2S -35.94 b) Compound Solubility constant (Ksp) FeS -2.95 ZnS -8.95, -10.93 PbS -13.97 FeS2 -16.4 Cu2S -34.65 Ag2S -35.94 HgS -39 39 (51.8% ) and 1 0 9 A g (48.2%). Radioisotopes of Ag range from mass numbers 102 to 112 but none occur naturally. 110mAg is a beta emitter and has the longest half-life of the radioisotopes at 253 days which makes it suitable for chemical tracer work. The silver salts AgCl, AgBr and Agl are relatively insoluble in water except for AgF. In the presence of excess halide, water-soluble complexes may form. For marine waters the major dissolved complexes of Ag were determined to be the chloride complexes, which in order of importance are AgCl2" = AgCl3~2 > AgCl4"3 > A g C l ^ (Savenko and Tagirov, 1996). In fresh waters Ag+ is the dominant species. However, at a salinity ~ 6 AgCl is equally important. Complexes of silver with hydroxide, carbonate, sulphate and nitrate are considered insignificant in natural waters. Experimentally, Ag forms complexes with organic compounds and bonding is considered to occur through sulphur linkages rather than oxygen or nitrogen. At a sulphide concentration of 0.01 ug/L and greater AgHS is the most abundant complex. At a value of 0.0001 ug/1 hydrogen sulphide the concentration of AgHS is less and chloride complexes dominate (Jenne et al., 1978). Miller and Bruland (1995) concluded that organic speciation of dissolved silver in seawater was unimportant, based on extraction experiments with diethyldithiocarbamate (DDC) and chloroform. They assumed that if Ag was strongly complexed to an organic ligand, it would not complex with DDC and would not be extracted as Ag-DDC complex with chloroform. However this approach would require that no Ag-organic complex dissolve in the organic (chloroform) layer. To check this they added a sulphur-containing organic ligand (glutathione) to seawater samples, and it did not significantly affect the amount of Ag extracted. Wen et al. (1997) indicated that the experiments by Miller and Bruland were performed on stored samples which may have affected the results since they found that dissolved Ag was associated with organic compounds in river and estuarine samples. According to Krauskopf (1979) minor elements can substitute for major elements of similar atomic radii in detrital minerals and the ability to substitute is reflected in the quantity of that element in the host. For example Ba, Rb and Pb have similar ionic radii to K and substitute for K in late-forming minerals such as K-feldspar and mica. Ringwood (1955) suggested that A g + , which also has a similar ionic radii to K, might substitute for K + . However this is not supported by the distribution of Ag in igneous rocks. Nesterenko et al. (1969) investigated the distribution of Ag in the Siberian platform to determine the behavior of Ag during differentiation in magma chambers. Silver is concentrated in both initial and late differentiates. Some Ag concentrates in the earliest 40 minerals formed and some remains in the melt until the last stages of differentiation. This distribution is difficult to explain by isomorphism, that is, the substitution of A g + for K + . For example plagioclase contains only 0.002 ppm of Ag. If substitution were occurring, the concentration should be much greater. Silver is also depleted in quartz however, high levels of Ag were found in sulphides ~16.2 ppm and values of up to ~ 200 ppm have been observed in chalcopyrite (Nesterenko et al., 1969; Boyle, 1968). Sulphides are thus considered the principal carriers of Ag in mafic rocks and basic rocks (Nesterenko, et al., 1969) and probably also account for the slight enrichments of Ag in black shales, black and sulphide schists, alum shales and phosphorites. Average concentrations in various rock types are listed in Table 3.8. 3.6.2 Distribution in Seawater Silver is supplied to the ocean naturally from the weathering of rocks. In the open ocean, silver concentrations range from -0.1-22 pM. Much higher concentrations are found (~ 250-300 pM) in some coastal waters that have been contaminated by industrial wastes (e.g. in San Francisco Bay and San Diego Bay; Smith and Flegal, 1993; Flegal and Sanudo-Wilhelmy, 1993). In the north east Pacific dissolved Ag concentrations range from ~ 1 p M near the surface to ~ 23 pM at depth. A minimum in dissolved Ag occurs at the chlorophyll maximum. This observation, and the fact that Ag has a distribution similar to the nutrient element Cu indicates that silver may be involved with particulate organic matter uptake-sinking-regeneration processes (Figure 3.8; Martin et al., 1983). Since the profile of Ag is similar to that of Cu, Ag may react the same way as copper. Thus, silver could be scavenged by organic matter and Fe/Mn oxides and upon reduction of the latter in the water column or in the sediments, the metal would be released (Boyle et al., 1977). Silver could then be readsorbed by clay minerals in the sediments or precipitated as the sulphide or coprecipitated with FeS (Hirst, 1974). Where a shallow oxic/anoxic boundary exists in sediments, Ag may be removed from the water column by diffusion into the deposits and precipitation as the sulfide. However more recent data suggest that the Ag distribution is most similar to that of Si and may be associated with the hard parts of phytoplankton cells or more strongly bound to cells. In the North Atlantic for example, total Ag concentrations are low at the surface (< 0.7 pM) and higher in deep waters (7 pM) (Figure 3.9), parallelling the distribution of dissolved 41 Table 3.8 Silver concentrations of various rocks and deposits. Values are from Smith and Carson (1977) unless noted otherwise. Concentrations are in ppm. Material Ag (ppm) Terrestrial (Boyle, 1968) 0.01-5 Lithosphere (Goldschmidt, 1954) 0.02 Continental crust (Taylor, 1964) 0.07 (average of basalt-0.1 ppm and granite 0.04 ppm) Silicic rocks-granites -grandiorites (Hamaguchi and Kuroda, 1959) 0.037 0.051 Quartzdiorites and diorites (Hamaguchi and Kuroda, 1959) 0.052 Silicic andesites (Hamaguchi and Kuroda, 1959) 0.080 Basalts (Hamaguchi and Kuroda, 1959) 0.10 Diabase (Hamaguchi and Kuroda, 1959) 0.12 Gabbro (Hamaguchi and Kuroda, 1959) 0.11 Ultramafic rocks (Hamaguchi and Kuroda, 1959) 0.060 Ultrabasic (Boyle, 1968) 0.08 Slate(Hamaguchi and Kuroda, 1959) 0.06 Sandstone 0.08 (0.25) Normal shale 0.10 (0.07) Black shale 0.32 (1-15) Limestone 0.07 (0.12) Coal (0.05) (0.5-Bertine and Goldberg, 1971) Coals 0.5-300 Oil shales <0.1(5-10) Petroleum 0.07-.124 Refined oils 0.095 (0.0001-Bertine and Goldberg, 1971) Anhydrite and gypsum 0.05 42 pmol Ag kg" ' i nmol Cu k g " ' Figure 3.8 Dissolved Ag concentrations versus depth measured in the Pacific Ocean. Dissolved Cu concentrations are shown for comparison (Martin et al., 1983). 43 Figure 3.9 Vertical profiles of total (unfiltered) silver concentrations (pM) in oceanic waters. Values indicated with circles, squares and diamonds are from the North Atlantic, South Atlantic and North Pacific, respectively (Flegal et al., 1995). 44 silicate (Figure 3.10; Flegal et al., 1995). Silver concentrations increase systematically in deep water from the North Atlantic through the South Atlantic to the North Pacific (Figure 3.9). Lee and Fisher (1994) concluded that the majority of Ag associates primarily with structural components of phytoplankton cells based on the fact that following consumption of diatoms by zooplankton, most of the silver was retained in the diatom cells and debris and only 27% was converted to zooplankton tissue (21%), fecal pellets (1%) and dissolved Ag. However, the diatoms were grown in seawater containing ~ 5, 200 pM Ag and it is likely Ag was also adsorbed to the surface of the phytoplankton. Thus, Ag may not necessarily be retained predominantly in the structural parts. Indeed, adsorption experiments by Sanders and Abbe (1987 and 1989) showed that Ag is strongly adsorbed to phytoplankton. Silver uptake occurred within 2 hours, and adsorption increased with increasing silver concentrations and decreased with increasing salinity (Sanders and Abbe, 1989). When phytoplankton containing adsorbed Ag at low salinities were placed in solutions of high salinity little of the Ag was released. Silver is thus either taken up in the cellular matrix or is bound tightly to cell surfaces. In contrast, 80% of the silver adsorbed to sand, silt, and clay particles was released in solutions of higher salinity. On balance, the evidence favours the incorporation of Ag from seawater into the frustules of siliceous plankton. 3.6.3 Solid Phases Associations between silver and various phases in sediments have been proposed. The metal may be incorporated into crystal lattices or adsorbed to the surfaces of clay minerals. Silver may be incorporated into or adsorbed onto organic matter. Similarly in the case of oxides, Ag may be incorporated into the atomic structure, or adsorbed to the surface. These observations are largely based on sediment-extraction or adsorption experiments. Chemical extractions attempt to remove metals from specific mineral phases using various reagents. Such approaches are strictly operational and it is unlikely that only one phase dissolves. Calvert and Pedersen (1993) point out that this method is controversial because selectivity is often dubious. An alternative approach is to compare the distributions of selected dissolved or sediment concentrations with those of other elements to identify potential hosts. Correlations may provide information on processes that control the Ag distribution in marine sediments, for example. Early adsorption experiments indicated that adsorption of Ag to Mn02, Fe oxides and 45 Figure 3.10 Relationship between total silver and silicate concentrations in the eastern Atlantic (Flegal et al., 1995). 46 clays is minor compared to the adsorption of the metal to organic matter (Krauskopf, 1956). Davis and Leckie (1978) confirmed these observations. They found that silver adsorption onto amorphous iron oxide was minor at a salinity of ~ 7, probably because formation of Ag-chloride complexes inhibits the uptake of Ag onto Fe oxides. However, adsorption of Ag onto the oxides was enhanced in the presence of glutamic acid, which presumably scavenged the silver and coated the oxide surfaces. Similarly, Luoma et al. (1995) found that silver was not taken up onto iron oxides unless they were coated with organic material such as bacteria. They also observed that chlorocomplexes do not prevent the association of Ag with natural particles. For example, at a salinity of 20, approximately 99% of silver was removed to sediment particles within 24 hours from an 80 ug/L solution of Ag. Luoma et al. (1995) concluded that amorphous coatings enhance Ag accumulation in sediments. Finally, radioactive labelled Ag-110m has been shown to bind tightly to the organic portion of sewage sludge (Chapman et al., 1988), and is not lost to solution when the sludge is subsequently diluted by seawater. 3.6.4 Sediments Silver is naturally enriched above the average crustal value in anoxic sediments and hydrothermal mineral deposits (Koide et al., 1986, Table 3.9). Sulphide minerals appears to host the silver in hydrothermal deposits. Sulphides are also likely hosts for silver in reducing sediments. Previous experiments with sulphate-reducing bacteria (Clostridium desulfuricans and Desulphovibrio desulfuricans) yielded Ag2S via the reaction of AgCl with S"2 produced from the reduction of S04"2 in artificial seawater (Baas Becking and Moore, 1961). This experiment showed that sulphite reducers are capable of forming Ag2S at low temperatures (< 30 °C). Based on this work, it is anticipated that silver sulphide is a likely host for silver in coastal sediments, which are invariably reducing at a shallow depth. 3.6.5 Anthropogenic Sources The primary source of industrial silver to the aqueous environment is the disposal directly to municipal sewers of photographic solutions by small processors and amateurs (Smith and Carson, 1977; Forstner and Whittman, 1981). Most of the Ag derived from the photographic industry that enters the sewage system is considered to be the soluble thiosulphate complex Ag(S203)2" 3. Manufacturing of Ag products and the polishing of silverware are also additions of Ag to waste waters. Silver compounds used in analytical 47 Table 3.9 Silver concentrations in various marine deposits (Koide et al., 1986). Note that Whites Point deposits are impacted by sewage wastes. Material Ag (ppm) Ferromanganese nodules 0.03-0.18 Marine sediments (blue mud)(Hamaguchi and Kuroda, 1959) 0.10 and 0.15 Anoxic sediments 0.24-1.3 Hydrothermal deposits 0.68-88 Phosphorites 0.04-0.08 Pelagic sediments 0.02-0.31 Whites Point 13-20 48 chemistry are considered a minor source of Ag (Smith and Carson, 1977). Minor amounts of silver may also be introduced to sewer systems through electroplating wastes, which contain silver as the silver cyanide complex (Ag(CN)2~) at concentrations as high as ~ 250 ppm or 0.25 g/L in raw waste. In treated wastes, cyanide has commonly been destroyed by oxidation with chlorine, using either chlorine or hypochlorite. Treated wastes contain ~ 0.001-0.003 g/L of silver in the form of the chloride or hydroxide or residual cyanide complexes (Smith and Carson, 1977). Atmospheric emissions are also considered minor. Losses of Ag to the atmosphere occur from the burning of fossil fuels and municipal refuse, mining, milling and smelting of lead, lead-zinc, silver and copper ores. Silver is also lost as aerosols during the fabrication and polishing of Ag metal and during cement and iron and steel production. Atmospheric emissions are considered to be only a small fraction of anthropogenic inputs of silver into the environment, but the exact proportion is uncertain. Silver enrichments in sediments near a lead and copper smelter in Puget Sound are attributed to waste water inputs through sewage outfalls rather than aerosols supports that atmospheric inputs are insignificant compared to waste water sources (Bloom and Crecelius, 1987). Bowen (1985) found elevated levels of 150 ppm and 740 ppm of Ag in particles released from burning refuse and sludge from Japan, suggesting that concentrations in combustion products from such sources can be very high. 3.6.6 Municipal Wastewater Silver values are much lower in municipal wastewater effluents (~ 0.048 - 40 ug/L) than in treated and untreated photographic waste (~ 500,000 to 5, 000, 000 ug/L). Concentrations measured in municipal water of Vancouver range from < 5-10 ug/L (Koch et al., 1977). Wastewaters from U B C may contain slightly higher Ag contents (< 5-36 ug/L). Typical values in the Iona influent and effluent are ~ 11 ug/L and 9 ug/L (GVRD, 1994), while concentrations in sewage particles are much greater ~ 27 ppm (Bertold, 1996), implying that most Ag is associated with the particles. Indeed, Galloway (1979) estimated that only -5% of Ag is in the dissolved state in sewage waste. Dissolved Ag in wastewater is likely complexed with thiosulfate, chloride, and sulphide and possibly soluble organic complexes. The average dissolved concentration of Ag in Iona wastewater is below the saturation point of AgCl. Suggesting that the formation of AgCl in the sewage system would likely be minor. Particles that remain on a 0.45 um pore-size membrane after filtering of influent are mostly organic (~ 75%) while the solids remaining from evaporation (at ~ 100 °C) of the 49 filtrate are ~ 60% mineral salts and ~ 40% organic (Grace, 1978). The sewage influent of Iona has a yearly average suspended solids content of 143 mg/L of which about 85% is organic (GVRD, 1993a). As noted earlier, under reducing conditions Ag is likely to be present as particulate sulphides or as sulphide or hydrogen sulphide complexes (Jenne et al., 1978; Morel et al. 1975). The influent at Iona is typically reducing since it contains measurable sulphide (on average ~ 700 ug/L). In the effluent, the sulphide concentration is on average < 100 ug/L (Jenne et al., 1978). Thus, the most likely hosts for silver in sewage wastes are sulphides and organic matter. 50 Chapter 4. Results Sediment samples were analyzed for Ag, 8l3corg, and S ^ N and for inorganic carbon, total carbon, sulphur, and nitrogen. Organic carbon was determined by the difference between total carbon and inorganic carbon. Major and minor elements were also determined, and all the data were used collectively to characterize the sediments. A l l results are listed in Appendix 4, and the analytical procedures used are outlined in Appendix 1. Only selected elements that assist in determining the distribution of sewage or defining the controls on silver distribution are discussed in this chapter. A l l concentration data have been corrected for bulk dilution by seasalt and for specific contributions from major elements in seasalt (see section A1.8, Appendix 1). 4.1 Silver Silver concentrations in surface sediments collected between May 1994 and July 1996 in the Strait of Georgia are presented in Figure 4.1. Silver values for samples from similar locations but sampled in different years are relatively similar (Table A4.9, Appendix 4). Compared to sediments in the deeper waters of the Georgia Strait, silver is enriched in sediments near the Iona outfall, on Sturgeon Bank near the Iona sewage treatment plant and in Burrard Inlet. Silver levels range from 44 ppb to 1,440 ppb. Low values of ~ 50 ppb and -130 ppb bracket the average shale value of ~ 70 ppb (Bowen, 1966) and are found in coarse-grained sediments on the tidal flats of Sturgeon and Roberts banks and in distal fine-grained sediments in the central basin of the Strait and Roberts Bank, respectively. High Ag concentrations characterize sediments immediately north of the Iona outfall and near the Iona sewage treatement plant on Sturgeon Bank. Values at the latter site are higher (> 1000 ppb) than levels north of the outfall (~ 700-800 ppb). The area of highest Ag enrichment on Sturgeon Bank is a site where sewage effluent was discharged from 1963 to 1988. In 1988 treated effluent was diverted to the deep outfall. However, untreated sewage is occasionally discharged to this area when the plant is overloaded during periods of high rainfall. Intermediate concentrations ranging from ~ 400-600 ppb are found in three areas: near the Iona outfall, the Iona sewage treatment plant on Sturgeon Bank, and in Burrard Inlet (Figure 4.2). Values for samples from nine transects ranging across water depths of 20 to 200 m are listed in Table 4.1. The diffuser section of the Iona outfall sits on the delta foreslope between ~ 70 and ~ 105 m water depth (GVRD, 1989a). Silver values greater than 400 ppb 51 Figure 4.1 Distribution of Ag in Strait of Georgia surface sediments. The sample locations on which this map is based are shown in Figure 1.1. 52 Figure 4.2 Distribution of A g in surface sediments near the Iona sewage outfall and on Sturgeon Bank near the Iona sewage treatment plant. The sample locations on which this map is based are shown in Figure 1.2. 53 Table 4.1 Silver concentrations in surface sediments in ng/g north (N) and south (S) of the Iona outfall diffuser section. Sediments were sampled along transects running west to east from water depths of ~ 200 m to ~ 20 m. Values are salt corrected. For sample locations see Figure 1.2 and Appendix 2. Transect 200 m 170 m 130 m 110m 90 m 70 m 50 m 40 m 30 m 20 m 6N 246 347 357 453 510 454 338 268 297 168 5N 223 310 366 591 357 371 385 342 241 202 4N 279 454 686 630 544 564 321 246 196 3N 280 438 606 635 567 399 383 363 225 2N 287 450 850 698 555 410 403 231 222 IN 264 426 743 724 497 268 127 196 143 Diffuser IS 248 330 524 436 447 289 222 2S 231 291 301 356 267 174 124 3S 218 245 285 315 322 240 150 54 extend to the north and south of the outfall in a narrow band between depths of ~ 50 and 130 m. Silver concentrations > 400 ppb are found up to ~ 6 km north of the outfall but only ~ 1 km to the south, and the width of the 400 ppb contour to the north (~ 2 km) is approximately double the width to the south. Silver values in sediments near the outfall (~ 400-800 ppb) are similar to those found in sediments from Puget Sound (Bloom and Crecelius, 1987), the New York Bight (Bothner et al., 1994) and Cape Cod Bay (Ravizza and Bothner, 1996). The increase in Ag in these three embayments is attributed to the input of sewage waste. East and west of the band of high Ag, concentrations drop sharply to < 200 ppb and < 300 ppb, respectively. Further to the west, surface sediments remain enriched, and only approach the average shale value in the deep basin of the Strait. Values greater than 300 ppb extend northward into Burrard Inlet and about 4 km south of the outfall. On Sturgeon Bank high Ag values extend nearly 2 km southwest from Iona between the Iona Jetty and Sea Island (Figure 4.2), particularly along the shore of the latter. Concentrations on Roberts Bank are much lower overall (< 200 ppb) than near Iona (> 400 PPb). For comparison, silver concentrations were determined in surface sediments from other coastal areas in British Columbia. Values for Knight Inlet (KN1) and the inner basin of Howe Sound (KD74) are similar to those measured in the deep basin of Georgia Strait (~ 130 ppb). Somewhat higher concentrations are found in Jervis Inlet (JV7; ~ 200 ppb), close to the Britannia mine in the inner basin of Howe Sound (KD71; ~ 250 ppb), and the outer basin of Howe Sound (KD18; ~ 230 ppb). Samples from Saanich Inlet, a periodically anoxic basin, range from -160 ppb (SAG26) in the centre to values between - 200 ppb (SAG3) and 270 ppb (SAG1) near the head. Silver concentrations at two sites in Indian Arm are very much higher: - 820 ppb at STN18 and - 1,070 ppb at STN35. These values are comparable to the highest concentrations found near the outfall and Iona, respectively. Vertical profiles of Ag in nine sediment cores are presented in Figure 4.3. Concentrations range from - 50 ppb to 3, 300 ppb. The lowest Ag values are found in the coarse-grained sediments of core A12 and at the bottom of core A O , while slightly higher levels are found in fine-grained sediments in core SG55 from the deep waters (~ 410 m) of the Strait. Closer to Vancouver, cores SG4, VG1 and 5903 host Ag concentrations that vary little between 210 ppb and 260 ppb. Higher values are found in cores AG17 and AG54 located immediately north of the outfall and in Burrard Inlet, both of which have relatively constant values in the top - 9 cm. Core SG29 was collected and sampled a year earlier; silver distributions are very similar in both. 55 o o o I I I I I I I I I I I I I I I I I I I I I I I I I I o >n < o < o O < • I I I I X 2 J o o o o o o o I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I "*f t> ON >0 <—' "0 ^ O o g a o > < < 0 0 C/3 CO o ON (uio) ipctea o ^ 1 1 £•§ S S ^ ON > O CM <u -> o « g ^ « „ s I? -A 5 CNI o S 2 m •s c o m " o o —1 io •a spr 8 ON 'SJ o § O . S S on ©ir-- " A o an _ TO ^  P o 1 .2 s T3 -5 •o c .a ? c <*> > C !A 6 0 O 'O Tt = < .2 D p fe a ra S .2? 3 E 5 o m -s 8 z 56 Core A O , collected from a site near Iona on Sturgeon Bank, has the highest Ag values reported here: ~ 3, 200 ppb. The silver content in core A O spans a dynamic range from ~ 50 ppb in the coarse sediments at depth to the shallow subsurface maximum of ~ 3, 200 ppb (Figure 4.3b). Values are lower in surface deposits (~ 1, 300 ppb). The distributions of Ag and Ag/Al ratios are similar in surface sediments and in the cores, where Ag /Al ratios range from ~ 1.0 x 10^ in core A12 up to 50 x 10 6 in core A O (2-4 cm) (Figure 4.4). A l l Ag /Al ratios computed in this study exceed the A g / A l value estimated from average shale (~ 0.8 x 10^, based on the data from Bowen (1966) and Calvert and Pedersen (1993)). Silver concentrations in sediment size fractions of selected samples north of the outfall and from Sturgeon and Roberts banks are presented in Figure 4.5a and 4.5b and are listed in Table A4.12, Appendix 4. Higher Ag values are typically found in the < 63 pxn fraction for most samples. However the highest Ag contents in A14 and SG32 occur in the fine sand fraction, while in A G 14 and A G 13 silver is most enriched in the coarse material (Figure 4.5). 4.2 Carbon and Nitrogen Isotopes Distributions of 8 l 3 C 0 r g and 8^N in surface sediments of the Strait of Georgia contrast markedly with the silver distribution. Unique signals near the outfall or Iona are not observed (Figures 4.6 and 4.7). Values for both 8 l3c 0 rg a n d S ^ N near the outfall are similar to measurements made on samples from sites located on southern Sturgeon and Roberts banks and midway between the delta front and the deeper waters of the Strait. Moreover, heavier 8l3co rg values near Iona are similar to measurements made on sediments in the deep waters of Georgia Strait. Surface sediments of the tidal flats and Burrard Inlet are characterized by low S ^ N values (2.1-4.5%o), with the lowest values in coarse-grained sediments on the tidal flats and shallow water depths along the foreslope (Figure 4.8). Generally, S l ^ N values become heavier in sediments along the transects to the west (Figure 4.8). However, for the three transects immediately north of the outfall, samples from the middle of the transects have slightly lower 8^N values (< 3.0%o) than in samples both to the east and to the west (~ 3-4%o). The highest values are found in the Strait of Georgia (~ 5-6%o). Likewise, 8 i 3 C 0 r g values are lighter (< -23.5%o) to the east along the transects than those to the west along the transects (> -22.50%0) (Figure 4.9). Light values (~ -24%0) are found on Roberts Bank and heavy values (-20.9%o to -22.2%o) on both Sturgeon Bank and in the central basin of the Strait of Georgia. Measurements overall range from a high of 57 o i i i i i i i i i i i ' i i i i i i i i i i ' CN t— OS o -<r> CM < O U o < Vi < Vi --' 0 ' — : o O o O (uio) qidsa o 1 I 1 1 1 1 I 1 ' 1 1 I 1 1 1 1 I CN i/i < o to o Vi •* t- o\ w> — CM a o a < < 00 • 1 1 • • • • i ' i i i i i i i i ' i i i i i i i i i i i ' i i O o in o o 58 CN 2-S . * g a ^ u ^ < S • 8 s l < oo pg q a e o CU 7? 0 0 S 8 ••A — c fa ^ 2 o u - o> g • ^ « « o ^ ^ fe O-S a •§£ £ g oo g E pa < o A o •A J O O CD > cu eS < , CD T3 > C CS C3 500 400 •g, 300 W) 200 < 100 0 Total Silver >125 63-125 <63 Fraction (|jrn) 1200 1000 800 OH 600 400 200 0 • SG32 H SG31 • AG17 AG16 AG 14 u AG 13 Total Silver >125 63-125 : <63 Fraction (|Lim) Figure 4.5a) Silver concentrations in mud (< 63u m), fine sand (63-125|im), and coarse sand (> 125 um) size fractions of selected surface samples (except for SG56 which was sampled at 2-3 cm). SG56 is from the deep waters of the Strait and was very fine grained (100 % < 63n m). A14 is from Roberts Bank and A12 and HC2 are from Sturgeon Bank;b) samples from a transect north of the outfall (2N). Water depth decreases from SG32 to AG13. Sample locations are shown in Figures 1.1 and 1.2 and in Tables A2.1 and A2.2 in Appendix 2. 59 Figure 4.6 Distribution of 6 '^N in surface sediments of the Strait of Georgia. Sample 5911 is not included. Sample locations are shown in Figure 1.1. 60 Figure 4.7 Distribution of 6 C 0 rg in surface sediments of the Strait of Georgia. Sample 5912 is not included. Sample locations are shown in Figure 1.1. 61 Figure 4.8 Distribution of S ^ N in surface sediments near the Iona outfall and Iona sewage treatment plant. Sample locations are shown in Figure 1.2. 62 Figure 4.9 Distribution of S ^ C o r g in surface sediments near the Iona outfall and Iona sewage treatment plant. Sample locations are shown in Figure 1.2. 63 -24.77%o to a low of -20.88%o, which both occur on the delta front. Vertical profiles of 8 ^ N and 8 ^ C o r g in sediment cores are presented in Figures 4.10 and 4.11. High S^N values of ~ 6.0%o are found in cores from the central basin of the Strait of Georgia (SG55, SG4) and Burrard Inlet (AG54). Low 5 1 5 N values (~ 2.0 to 4.0%o) in cores A O , SG29 and in the top of core A G 17, and intermediate values (~ 4.0%o to 5.0%o) are found in cores VG1 and A G 17 below ~ 6 cm depth. In contrast to the S^n core data little overlap is observed for 8 ^ C 0 r g core data (Figure 4.11). The highest values are found in core SG55 ~ -21.5%o to -22%o and decrease progressively towards Vancouver to -23.5%c in core AG54. Cores AG17, SG29 and A O contain the lowest 5 ^ C 0 r g of ~ -24.0%o. The lowest value is found in core A O at mid-depth of ~ -25%o where wood is present and slightly higher values occur both at the top and bottom of core A O of ~-23.0%o. 4.3 Si/Al Silicon to aluminum ratios in surface sediments of the Strait of Georgia range from ~ 3.31 to 6.30 (Figure 4.12). Ratios greater than ~ 5 are found in coarse-grained sediments on Sturgeon Bank. Slightly lower values are found in samples from shallow water depths along the foreslope near the outfall and at site A O on Sturgeon Bank near Iona. Ratios decrease westward along the transects to ~ 3.5, and are similar to those found in the deeper waters of the Strait. High Si /Al ratios (~ 5.3-6.1) are found in coarse-grained sediments of core A12 and the bottom six samples of core A O on Sturgeon Bank (Figure 4.13). Low ratios (~ 3.4-3.6) occurs in fine-grained sediments from the deep basin of the Strait (SG55, SG4), Burrard Inlet (AG54) and in one layer of core A O at mid-depth of ~ 3.3. Values increase in core A O to ~ 5.2 a few cm above and then decrease gradually to ~ 4.0 in the top layer. Ratios in surface sediments in cores A O , SG29 and AG17 are similar. Below ~ 10 cm in core AG17, the ratios are similar to those observed in SG4. 4.4 Organic Carbon The organic carbon distribution in surface sediments of the Strait of Georgia is illustrated in Figure 4.14. Concentrations range from 0.12% to 2.64%. Coarse-grained sediments on Sturgeon Bank and Roberts Bank contain the lowest C 0 r g values of less than 0.2%. Samples located to the east in transects north and south of the outfall have contents of 64 S^N* (0/00) Figure 4.10 Vertical distributions of 8 1 5 N in cores from the Strait of Georgia (SG55, SG4, VG1), north of the Iona outfall (AG17, SG29), west of Burrard Inlet (AG54), and Sturgeon Bank (AO). 65 5 1 3 r (0/00) P D B -26 -25 -24 -23 -22 -21 -20 0 ^ 20 3 30 £ 4 0 Q 50 60 70 10 P i i i i | i i i i • • • 1 VG1 i i i i i i i • i i i Figure 4.11 Vertical distributions of 8 1 3 C 0 r g in sediment cores from the Strait of Georgia (SG55, SG4, VG1), north of the Iona outfall (AG17, SG29), west of Burrard Inlet (AG54), and Sturgeon Bank (AO). 66 Figure 4.12 Distribution of Si/Al ratios in surface sediments of the Strait of Georgia for samples 59-series,VGl-5, SGI-32, SG39-59, AO, A12, KA1, KA2, W6, W7, and W8 only. Sample locations are shown in Figure 1.1. 67 Si/Al Figure 4.13 Vertical distribution of Si /Al ratios in sediment cores from the Strait of Georgia (SG55, SG4), north of the Iona outfall (AG17, SG29), west of Burrard Inlet (AG54), and Sturgeon Bank (A12, AO). 68 Figure 4.14 Distribution of organic carbon (Corg) in surface sediments of the Strait of Georgia. Values are in weight percent. Sample 5912 is not included. Sample locations are shown in Figure 1.1. 69 ~ 0.3 -1.0%. Similar concentrations are found in several samples from Sturgeon Bank and Roberts Bank. The highest values on the tidal flats of Sturgeon and Roberts banks (~ 1.6%) are within the range found in sediments in deeper waters from the western portion of the transects near the outfall (~ 1.3-1.7%). Higher concentrations (~ 1.8 to 2.6%) are observed in sediments from the deep central basin of the Strait. Organic carbon contents in various samples from Sturgeon Bank, Roberts Bank and north of the outfall correlate with the percent mud in the samples (r2=0.96). In general, there is a trend of increasing Ag concentrations with increasing C 0 r g contents in sediments from the tidal flats compare (Figures 4.2 and 4.15): both increase toward the shore. In the area of Sturgeon Bank between the Iona Jetty and Sea Island the relationship is less consistent. For example samples from a transect immediately south of the Iona Jetty C 0 r g values of ~ 0.3%, ~ 0.5% and ~ 0.7% have increasingly higher Ag values of ~ 100 ppb, ~ 265 ppb and ~ 300 ppb, respectively. However there are exceptions to the trend in the area between the jetty and Sea Island where samples with similar Corg different Ag concentrations (~ 345 ppb, -417 ppb and ~ 500 ppb) are found. The trend between Ag and C 0 r g is not observed in sediments along the foreslope and deeper waters of the Strait. Vertical distributions of C 0 r g in sediment cores are presented in Figure 4.16. Core A12 and the bottom of core A O contain the lowest concentrations (< 0.4%), while higher contents are seen in A O at ~ 13 cm depth (~ 2.2%) and at the surface of the core. The C 0 r g peak at mid-depth occurs in the same interval where the S^Corg is light and wood was observed. Organic carbon concentrations in cores from the Strait (SG55, SG4) decrease slightly with depth. Similar profiles are observed in cores north of the outfall (AG 17) and in Burrard Inlet (AG54). The highest C 0 r g contents occur in SG55 from the deep basin (~ 2.0%, near the surface), and decrease in cores closer to Vancouver (VG1, AG54). 4.4.1 C/N Weight Ratios Organic carbon to nitrogen weight ratios in surface sediments of the Strait of Georgia range from ~ 7 to 18. Many surface and core sediment samples from the tidal flats contain nitrogen below the working detection limit of the analysis including most samples in cores A O and A12, and are not presented in the results. Typically sediments from the deep basin of the Strait are characterized by C/N ratios of -9-10. Sediments extending north of the outfall to Burrard Inlet and southeast to Sturgeon 70 Figure 4.15 Distribution of organic carbon (Corg) in surface sediments near the Iona outfall and Iona sewage treatment plant. Sample locations are shown in Figure 1.2. 71 C (wt. %) Figure 4.16 Vertical distributions of Corg in sediment cores from the Strait of Georgia (SG55, SG4, VG1), north of the Iona outfall (AG17, SG29), west of Burrard Inlet (AG54), and Sturgeon Bank (A12, AO). 72 and Roberts banks exhibit C /N ratios of approximately > 10 (Figure 4.17). The highest values are found near the North Arm Jetty where 8l3co rg values are light and pieces of wood are present. High C /N values of ~ 14 are also found in Burrard Inlet. Organic carbon to nitrogen ratios in the cores range from ~ 9 to 13 (Figure 4.18). Generally, high values of ~ 12-13 are found in A G 17 and SG29 north of the outfall, low ratios ~ 9 are found in SG4 and SG55 from deep waters of the Strait, and intermediate values (~ 10-11) are found in VG1 and AG54. The ratios are fairly constant with depth except in core SG55 where values of ~ 9 in the surface decrease slightly to ~ 8 at depth. 4.4.2 Sulphur Salt-free sulphur contents range from 0.01-0.19% in surface sediments (see Figure 4.19), except for two samples (SG50 and AO) which host higher concentrations of 0.26% and 0.36%, respectively. The distribution in surface sediments is similar to that of C 0 r g in that the lowest S contents (< 0.03%) are found in coarse-grained sediments at shallow water depths near the outfall and on Sturgeon and Roberts banks. Higher values are found near shore on Sturgeon Bank and west of the outfall into the Strait. Likewise the lowest S concentrations (< 0.03%) are found in cores A12 and the bottom of A O in coarse-grained sediments (Figure 4.20). Values are relatively similar in other cores from the Strait (SG55, SG4, VG1), and from north of Iona (AG17, SG29) and Burrard Inlet (AG54). Concentrations in the upper section of core A O are much higher. 4.5 Major and Minor Element and Element Ratio Distributions . 4.5.1 Manganese Manganese concentrations in surface sediments of the Strait range from ~ 600 ppm to ~ 16,700 ppm in the deep basin of the Strait (Table A4.2), with low contents (~ 600-700 ppm) occurring on the delta and the foreslope, and the higher values in the deep central basin. Manganese to A l weight ratios (x 10^) show a similar distribution to Mn in surface sediments of the Strait of Georgia and are presented in Figure 4.21. Ratios are generally high (>200) in the deeper waters of the Strait and highest in the deep central basin. Relatively low ratios similar to the average shale value of 96 x 10^ (Calvert and Pedersen, 1993) are found on Sturgeon Bank and west of the transects north and south of the outfall. 73 Figure 4.17 Distribution of organic carbon to nitrogen (C/N) weight ratios in surface sediments of the Strait of Georgia. Nitrogen values for several samples are below the detection limit (see Table A4.1, Appendix 4), which precluded their inclusion in the map. Sample locations are shown in Figure 1.1. 74 Co r c/N o o 10 L 20 : % 30 I * 40 50 t 60 70 i i i i I i 1 1 20 JL_I l _ J I I I I I I I I L Figure 4.18 Vertical distribution of Corg/N ratios in sediment cores from the Strait of Georgia (SG55, SG4, VG1), north of the Iona outfall (AG17, SG29), and west of Burrard Inlet (AG54). Cores A12 and AO with nitrogen values below the detection limit are not included. 75 Figure 4.19 Distribution of salt-free sulphur in surface sediments of the Strait of Georgia. Sample locations are shown in Figure 1.1. 76 Figure 4.20 Vertical distributions of salt-free sulphur in sediment cores from the Strait of Georgia (SG55, SG4, VG1), north of the Iona outfall (AG17, SG29), west of Burrard Inlet (AG54) and Sturgeon Bank (A12, AO). 77 Figure 4.21 Distribution of Mn/Al ratios in surface sediments of the Strait of Georgia for samples 59-series, VG1-5, SGI-32, SG39-59, AO, A12, KA1, KA2, W6, W7, and W8 only. Sample locations are shown in Figure 1.1. 78 Vertical distributions of Mn/Al ratios in cores A O near Iona and SG29 north of the outfall are relatively constant and are similar to the ratio in average shale (Figure 4. 22a). Much higher ratios characterize the upper one or two centimeters of cores SG4 and SG55 (Figure 4.22b) and are attributed to the presence of significant concentrations of manganese oxides in the near-surface deposits at these locations. 4.5.2 Fe/Al Iron concentrations in the sample set range from 2.8 to 4.4 wt. % (Table A4.3). Iron to aluminum weight ratios range from 0.49 to 0.69 in surface sediments of the Strait (Figure 4.23). Most samples in the deeper waters fall within the range ~ 0.54-0.60, while coarse-grained sediments on Sturgeon Bank and samples near Iona embrace a broader spectrum (~ 0.49-0.65). Samples from shallow water depths north and south of the outfall typically have lower ratios (~ 0.50) than samples at greater water depths. In general, Fe/Al ratios are lower in coarse-grained sediments and higher in fine-grained deposits. However a few coarse-grained samples on Sturgeon Bank exhibit high ratios. Vertical profiles of Fe/Al ratios are shown in Figure 4.24. Low Fe/Al ratios occur in core A12 and at the bottom of core AO. Higher values (~ 0.60) are found in fine-grained sediments in cores SG4 and AG54 and in SG55 (~ 0.6-0.7). There are slight relative iron enrichments in the surface layers of core A12 (from ~ 0.50 to ~ 0.57) and in core AG54 (from ~ 0.58 to ~ 0.66). Ratios in core A O are relatively low and somewhat variable with depth. 4.5.3 P/Al The phosphorus concentration in the sample set ranges from 0.06 to 0.16 wt. % (Table A4.3). Phosphorus to aluminum ratios (x 10^) in surface sediments of the Strait range from ~ 11-21, the lowest ratios (~ 11-13) occurring in coarse-grained sediments from shallow water depths north and south of the outfall. A slight relative phosphorus enrichment occurs in the uppermost cm in core A O (Figure 4.25). Higher ratios are found in the deeper waters of the Strait (~ < 20), and peak at the top of core AG54 (~ 26). 79 <3 r O O C/0 <0 ) a 53 O eet ° . s . (UIO) LjldSQ o o H. o CM n as < < s s o o <3 _l I I I I I I I I I t I I I 1 I I I I I I L_ o o o o o ^ —i <n m rt m o O (uio) ipdoa 80 Figure 4.23 Distribution of Fe/AI ratios in Strait of Georgia surface sediments for samples 59-series, VG1-5, SGI-32, SG39-59, AO, A12, KA1, KA2, W6, W7, and W8 only. Sample locations are shown in Figure 1.1. 81 Fe/Al Figure 4.24 Vertical distribution of Fe/Al ratios in sediment cores from the Strait of Georgia (SG55, SG4), north of the Iona outfall (AG17, SG29), west of Burrard Inlet (AG54), and Sturgeon Bank (A12, AO). 82 P/Al (*103) Figure 4.25 Vertical distribution of P /Al ratios in sediment cores from the Strait of Georgia (SG55, SG4), north of the Iona outfall (AG17, SG29), west of Burrard Inlet (AG54), and Sturgeon Bank (A12, AO). 83 4.5.4 Pb/Al Lead concentrations in the sample set range from 10 to 60 ug/g (Table A4.1). The surface distribution of the Pb/Al ratio in sediments of the Strait is shown in Figure 4.26. High ratios of-3.0-3.4 (x 104) are found near Iona, north near Howe Sound and in the deep basin of the Strait. Lower ratios occur in shallow waters along the foreslope near the outfall (~ 1.8-2.8 x 10' 4), and are similar to the ratio in average shale (~ 2.5 x 10"4). The lead to aluminum ratio profile in core A O is similar to both the Ag and A g / A l distributions in the core. Ratios increase above 20 cm from ~ 1.4 x 10" 4 at depth to ~ 3 x 10" 4 at 6 cm and to ~ 9 x 10"4 at 3-4 cm before dropping sharply towards the surface (Figure 4.27). Lower ratios are found in cores A12 and in the top 8 cm of cores SG4 and AG54, while slightly higher values characterize cores A G 17 and SG29 north of the outfall. Much higher ratios (~ 3.0-4.5 x 10"4) are observed below 8 cm in cores SG4 and AG54. 4.5.5 Cu/AI Copper contents in the Strait of Georgia surface sediments range from 10 to 70 ug/g (Table A4.2). Cu/Al ratios in surface sediments are shown in Figure 4.28. Values range from ~ 2.0 to ~ 7.6 (x 10 4) and bracket the average shale value of ~ 5.1 (x 10 4) (Calvert and Pedersen, 1993). Higher values are found in fine-grained sediments and are slightly enriched near the outfall and north near Howe Sound. Ratios in coarse-grained sediments on Sturgeon Bank are low (~ 2.0-2.6 x 10~4) but increase (~ 4.4-6.2 x 10"4) near site A O . Easternmost samples in transects north and south of the outfall have values higher than in the coarse-grained sediments and slighdy lower than near Iona. Ratios increase to the west and in a few samples north of the outfall. Ratios are low (-1-3 x 10"4) in coarse-grained sediments in core A12 and at the bottom of core A O (Figure 4.29), whereas high ratios occur in cores SG55 and SG29 (~ 6-8, and ~ 7-9 x 10"4, respectively). However values in a sub-surface peak at 3 cm depth in core A O are still higher. 4.5.6 Zn/Al Zinc concentrations in the sample set range from 60 to 130 ug/g (Table A4.2). The distribution of the Zn/Al ratio in surface sediments is presented in Figure 4.30. Ratios are generally low (~ 11-13 x 10"4) in coarse-grained deposits on Sturgeon Bank but are slightly 84 Figure 4.26 Distribution of Pb/Al ratios in surface sediments of the Strait of Georgia. Sample locations are shown in Figure 1.1. 85 Pb/Al (*104) o o 10 20 I 30 40 50 60 70 I I I I I K 2 4 6 8 10 TTI I I I I | I I I I I I I I I | I I I I I I I I I ' ' ' 1 1 ' 1 ' ' • 1 1 1 1 1 Figure 4.27 Vertical distribution of Pb/Al ratios in sediment cores from the Strait of Georgia (SG4), north of the Iona outfall (AG17, SG29), west of Burrard Inlet (AG54) and Sturgeon Bank (A12, AO). The value of the ratio in average shale is indicated for comparison (Calvert and Pedersen, 1993). 86 Figure 4.28 Distribution of Cu/AI ratios in surface sediments of the Strait of Georgia for samples 59-series, VG1-5, SGI-32, SG39-59, AO, A12, KA1, KA2, W6, W7, and W8 only. Sample locations are shown in Figure 1.1. 87 Cu/Al (*104) IK) r i . . . . 'i . . . . i Figure 4.29 Vertical distribution of Cu/Al ratios in sediment cores from the Strait of Georgia (SG55, SG4), north of the Iona outfall (SG29), and Sturgeon Bank (A12, AO). The value of the ratio in average shale is indicated for comparison (Calvert and Pedersen, 1993). 88 Figure 4.30 Distribution of Zn/Al ratios in surface sediments of the Strait of Georgia for samples 59-series, VG1-5, SGI-32, SG39-59, AO, A12, KA1, KA2, W6, W7, and W8 only. Sample locations are shown in Figure 1.1. 89 higher -14 x 10~4 near Iona. Values are fairly constant along transects north and south of the outfall (~ 14-15 x 10"4) and increase toward the west, reaching - 18-22 x 10" 4 in the deep central basin of the Strait. Relatively low ratios (~ 10-12 x 10"4) occur in core A12 and at the bottom of core A O (Figure 4.31), while significantly higher ratios are found in the uppermost half of core SG55. In contrast, ratios in core A O increase from - 8 x 10"4 at depth to - 17 x 10"4 at 16-18 cm, and are high near the surface. 4.5.7 Correlations Amongst Trace Metals in Core AO Ag/Al , Pb/Al, Cu/Al , and Zn/Al ratios all show enrichments in core A O at 2-4 cm depth (Figure 4.32), and all Ag /Al and Zn/Al values above 20 cm depth exceed the average shale value. The Cu/Al and Pb/Al ratios exceed average shale values in the upper decimetre. A l l metal ratios show a minor peak at 16-18 cm depth. Enrichment factors for the metals, taken as the maximum metal to A l ratio in core A O divided by the ratio in average shale, are - 64, 4, 2, 2 for Ag /Al , Pb/Al, Cu/Al, and Zn/Al, respectively. 90 Zn/Al (*104) 0 10 20 30 40 Figure 4.31 Vertical distribution of Zn/Al ratios in sediment cores from the Strait of Georgia (SG55, SG4), north of the Iona outfall (SG29), and Sturgeon Bank (A12, AO). The value of the ratio in average shale is indicated for comparison (Calvert and Pedersen, 1993). 91 o 10 B 20 o ^ 30 CD 40 50 0 0) I 0 CD CO a Ag/Al (*106) 20 40 60 i i i i Zn/Al A g / A l Cu/AI .e "a N _L EF(Ag) = 62 EF(Pb) = 4 -EF(Cu) = 2 -EF(Zn) = 2 — Core A O • ' • • • 1 J . i i i i 10 20 30 40 Pb/Al, Cu/AI, Zn/Al (*104) Figure 4.32 Vertical distribution of A g / A l , Pb/Al , Cu/AI, and Z n / A l in core A O . The value of the ratios in average shale are indicated for comparison (Bowen, 1966; Calvert and Pedersen, 1993)Enrichment factors represent the maximum metal to A l ratio in the core normalized to the ratio in average shale. 92 Chapter 5. Discussion The primary objective of this research project was to determine the controls on the distribution of silver in sediments of the Strait of Georgia and the comparative usefulness of silver as a sewage tracer in coastal environments. The data presented in Chapter 4 imply that the distribution of silver in the Strait of Georgia is influenced by a number of variables, the most important being sewage discharges. This factor and others that play either major or minor roles such as grain size, organic matter content and the presence or absence of sulphide phases wil l be discussed in this chapter. A second objective of the project was to investigate the utility of other sewage tracers, including stable carbon and nitrogen isotopes, in sediments. It will be shown that neither isotope ratio is suitable given the sedimentary context of the Strait of Georgia, which is dominated by inputs from the Fraser River. A similar conclusion will be drawn for the trace metals Cu, Pb, and Zn which only have limited utility in defining specific zones impacted by sewage deposition. The chapter will conclude with the suggestion that the concentration of silver enrichment on the Fraser River delta foreslope is not changing and has reached steady-state with respect to depositional conditions. 5.1 Silver as a Tracer of Circulation 5.1.1 Fraser River Foreslope Sedimentary silver enrichments in the Strait of Georgia are located near sites of sewage input (Figures 4.1 and 4.2). The distributions of silver both on the Fraser Delta foreslope and on Sturgeon Bank south of the Iona Jetty are consistent with the deposition of fine-grained sewage particles discharged from the Iona sewage treatment plant. The observed pattern on the foreslope is similar to that predicted, and confirmed through experiment, for the dispersion and deposition of fine-grained sewage particles (~ < 30 pim) discharged from a coastal marine outfall (Herring, 1980). The parameters used in Herring's case study were similar to those of Iona in that the outfall discharges primary treated effluent on a slope at about 70 m water depth into an area where currents are predominantly in one direction. Indeed, the silver distribution pattern on the Fraser delta foreslope reflects the results of Herring's model and experiments in which sewage particles were found to deposit within a few kilometres of the outfall in the direction of the primary current. The maximum number of 93 particles was found at the same depth as the outfall, and most particles were contained within a narrow path that trended downstream from the outfall. Thus the pattern of silver in sediments on the foreslope that extends mainly to the north of the deep Iona outfall indicates that mean flow direction between ~ 60 and 110 m water depth must be from south to north on the southeastern side of the Strait of Georgia. Moreover, the silver pattern is consistent with other indicators used to define deep flow direction in the Georgia Strait as well as with the known physical oceanography of the deep and intermediate waters in the basin. For example, a rhodamine dye injected into the Iona effluent and tracked offshore for several hours was found to move north from the outfall on both flood and ebb tides (GVRD, 1989a). The dye plume remained within a narrow width of about 1 km, about double the length of the outfall, indicating there is little lateral dispersion of the effluent plume as it travels northward. In addition, high numbers of fecal coliform bacteria were found in sediments along the foreslope at a similar depth as the outfall which is consistent with the high silver concentrations at the same depths (GVRD, 1995; Figure 5.1). However, in contrast to the silver distribution, coliform counts showed an abrupt transition from one site to the next. Bacteria are subject to die off and are sensitive to toxic components in the effluent, and this may account for the observed variability (Hirn et al., 1980; Gerba and McLeod, 1976). Silver, on the other hand, shows a relatively smooth transition from high to low values in a given transect (see Table 4.1). Consequently silver appears to be a more accurate and sensitive indicator of sewage transport and sewage inputs. Recent fecal coliform analyses in the water column (Bertold and Stewart, written communication, 1996) showed that the sewage plume is carried almost exclusively to the north, which further supports the conclusion of net unidirectional transport of the sewage. On both the flood and mixed tides the bacterial counts showed that the plume is typically located north of the outfall. However on the ebb tide, the plume was observed to the south but it did not reach as great a distance from the outfall as it did when it occupied the waters to the north. This behaviour is entirely consistent with the silver enrichment pattern seen in the sediments, which indicates predominant dispersion north of the outfall. The distributions of these various tracers fit well with the tidally-modulated deep current structure in Georgia Strait described by LeBlond et al. (1991). Dense water formed outside the Juan de Fuca Strait flows into the Strait of Georgia and spreads out northward and to the right. Water moves northward along the foreslope all year round as depths of inflow reach 200 m in the winter time and 350 m in the summer time. High sedimentary silver values extend northward from the Iona outfall into Burrard 94 476 3454 3453 180 3452 5431 5450 kn N 5449 5448 <aa' 5447 5446 * -476 477 kn E ' 478 479 3454 : 160 1.7 140 : 120 100 80 » 15.4 1.4 31 I • ! 63 L-'A 1100 <0.5 <0.5? Eo.3 <o.3 03 84 ! I 1 0 / 130 I / uof ua * + i 8.7 260; 15: !19: 477 kn E 478 J —I 5453 0 0.5 L0 KILOMETERS 5452 5451 BOTTOM CONTOURS REPRESENT WATER DEPTHS IN METRES BELOW THE CHS£ . DATUM AND ARE NOT NECESSARILY THE WATER DEPTHS AT. THE TIME OF SAMPING. DIFFUSERS LOCATED IN FINAL 505 n OF TWIN OUTFALLS 5449 METRIC MERCATTJR GRID 3448 • 1993 VALUES • 1994 VALUES 3447 FECAL COLIFORM COUNTS EXPRESSED AS MPN PER GRAM OF WET SEDIMENT S446 479 Figure 5.1 Distribution of fecal coliform in sediments near the Iona sewage outfall (GVRD,! 1995). 95 Inlet. Both distal Iona inputs and proximal discharges from other outfalls, including the Lions Gate treatment plant, are likely sources of the high silver concentrations in this area (BIEAP, 1997). Low values of silver (~ 250 ppb) in sediments near Britannia Mine, which are contaminated with other metals such as Cu and Zn (Drysdale, 1990), indicate that the mine is not a significant source of silver to either Howe Sound or outer Burrard Inlet. Although the silver-rich band on the foreslope tends to dominate appreciation of the Ag distribution in southern Georgia Strait it should be noted that enrichments of this metal are in fact found throughout the entire basin. Dating by Pb 210 on a sediment core (SG55; Figure 5.2) from the axial trough of the Strait indicates that silver enrichments appeared in the deposits sometime before 1950. A coincident increase in zinc implies that silver enrichments may have started as early as 1925 (Macdonald et al., 1991). These increases in silver predate the construction and operation of the Iona treatment plant which implies that the historic minor increases in silver throughout the Strait likely reflect general wastewater discharges from the city of Vancouver. Atmospheric emissions of silver may also have played a role; Ag is emitted during incineration of sewage sludge and smelting operations (Bowen, 1985) and these have occurred locally at the Lulu Island sewage treatment plant and at the A S A R C O Smelter in Tacoma, Washington. However, atmospheric inputs of silver in general are considered to be minor when compared to sewage inputs (Smith and Carson, 1977). 5.1.2 Sturgeon Bank The high silver values found nearshore and southward along Sea Island are consistent with the transport of sewage effluent towards shore on the high tide and with deflection to the south. Since fine-grained material tends to deposit near shore due to the tidal lag effect (Brown et al., 1989) the distribution of silver implies that the element is associated with fine-grained particles. Indeed, the silver distribution is similar to that of Corg on Sturgeon Bank. Because Corg is distributed hydrodynamically on the bank, this correspondence implies that the deposition of Ag is similarly controlled. Moreover, the absence of high silver values south of the jetty where treated sewage was discharged directly is consistent with the presence of strong currents in that area which result from the pile up of water due to winds. High shear velocities associated with these strong currents prevent the deposition of particles (GVRD, 1973). The high silver concentrations found at depth in core A G 17 located on the foreslope (Figure 4.3) suggest that sewage particles orginally discharged onto the mudflats at the end of the jetty also moved seaward and northward, and were eventually deposited on the foreslope. 96 0> > 3 0 2 4 6 8 1 10 12 14 Ln (excess 210Pb) 1.5 2 2.5 Figure 5.2 Ln (excess 210Pb) as a function of the cumulative mass in core SG55. 97 Increases at depth in core A G 17 predate the construction of the outfall, based on an estimated sedimentation rate of about 1 cm/year (Macdonald, written communication, 1996). This places deposits below 10 cm in the core as being pre-1988 and those above post-1988. The higher concentration of Ag found in the top 10 cm of this core is consistent with the increased addition of sewage particles to the area from the outfall in the last decade. 5.2 Other Controls on the Distribution of Silver 5.2.1 Grain Size Although the distribution of silver in Strait of Georgia sediments is primarily controlled by sewage discharges, grain size also plays an important role, particularly on the Fraser River delta and foreslope where sediment texture is extremely variable. High Si /Al ratios in coarse-grained coastal sediments typically reflect a higher proportion of quartz (Si02) in the deposits relative to clay minerals (Calvert, 1976). Because quartz is very resistant to physical weathering, it tends to be proportionately enriched in the coarser grain-size fractions. High Si /Al ratios of > 5 indicate the presence of coarse-grained material on the outer banks of Sturgeon and Roberts banks and east of the outfall along the foreslope (Figures 4.12 and 4.13). Lower ratios (~ < 3.5) are found in fine-grained sediments west of the outfall and in the deep waters of the Strait (Figure 4.12). Feeney (1995) found that both Si /Al and Corg correlated with grain size in Sturgeon Bank sediments. On the mudflats silver correlates to organic carbon (Figure 5.3) shows a similar distribution on Sturgeon Bank (Figures 4.2 and 4.15) and on Roberts Bank. Silver concentrations are naturally higher in finer grained sediments. For instance, silver concentrations in cores A12 (~ 50-60 ppb) and SG55 (~ 100 ppb) that represent coarse-grained and fine-grained end-members respectively show that lower values occur in the coarser material (Figure 4.3a). This is consistent with the low silver values reported for silicic rocks ~ 40 ppb and the higher values typically seen in marine muds (~ 100 ppb; Hamaguchi and Kuroda, 1959). Direct analyses of silver in various particle sizes confirms that the metal tends to be associated with the finer fraction (< 63 |im) (Figure 4.5). However in some samples from the Strait of Georgia relatively high values were found in the coarse-grained fraction. Similar results have previously been found in contaminated coastal sediments (Bloom and Crecelius, 1987; Lu and Chen, 1977; Ravizza and Bothner, 1996). Factors that could have produced the sporadically higher concentrations in the coarse fractions include: 1) an artifact resulting from 98 2000 1 ^nn L Sturgeon Bank r - ( h i g h A g ) # l—1—r o Strait ffl Diffuser • Sturgeon Bank (high Ag) -+ Sturgeon Bank (low Ag) -Sturgeon Bank - | (low Ag) • " " < > " " r2=0.88 0 o o 1 • • • • I • • ••• • 1 2 3 Corg (wt. %) Figure 5.3 Correlation between silver (Ag) and organic carbon (Corg) in Strait of Georgia surface sediments. 99 the presence of fine-grained particles in the dry-sieved coarse-fraction samples, and 2) the presence of silver-containing colloids which may have been bound to larger particles (Wen et al., 1997; Fisher etaL, 1995). 5.2.2 Association of Silver With Specific Sediment Phases The geochemistry of silver is not well known. Previous work suggests that organic matter and sulphides are the most important hosts for silver in marine sediments. Silver, a B-type metal is expected to precipitate as the sulphide under anoxic conditions, and indeed, enrichments of silver are observed in anoxic sediments (Koide et al., 1986). Silver is also known to be taken up by marine organisms (Reinfelder and Fisher, 1991; Wen-Xiong and Fisher, 1996; Luoma and Phillips, 1988; Fisher et al., 1995), phytoplankton (Sanders and Abbe, 1987), and the organic portion of sewage particles (Chapman et al., 1988). Furthermore, the vertical distribution of silver in sea water suggests that the element is involved in organic matter production and degradation (Martin et al., 1983; Flegal et al., 1995; Koide et al., 1986). Finally, adsorption experiments and sediment extractions indicate that oxide phases are typically a minor host for silver in marine sediments (Krauskopf, 1956; Davis and Leckie, 1978; Luoma and Bryan, 1981). Thus, several inorganic and biogenic phases in sediments can serve as significant hosts for silver. The potential influence of each in the Strait of Georgia will be discussed in the following sections. 5.2.2.1 Mn Oxides Manganese enrichments are observed in sediments underlying the deep waters of the Strait where M n / A l ratios are much greater than the average shale value ~ 92 (Figure 4.21). Ratios of M n / A l on the delta front and foreslope are similar to the average shale value due to high detrital inputs from the Fraser River. In coastal sediments a strong surface enrichment of Mn occurs as a result of diagenetic recycling (Shimmield and Pedersen, 1990; Calvert and Pedersen, 1996). Under reducing conditions at typically shallow subsurface depths, manganese is released to porewaters as M n + 2 which diffuses upward and is reprecipitated in the oxic zone as Mn02. Usually, the nearer reducing conditions are to the sediment surface, the greater the solid-phase surface Mn concentration. Diagenetic surface enrichments of this type are observed in cores SG4 and SG55 (Figure 4.22). The higher values of Mn found in core SG55 compared to SG4, suggest that the sedimentary redoxcline is closer to the surface in core SG55. 100 There is no evidence of an enrichment of Ag in the Mn-rich surface sediments in either of the two Georgia Strait cores (Figure 5.4). This is especially so in the relatively uncontaminated SG55. These observations provide very good evidence that Mn oxides are not a host for silver in Georgia Strait sediments, and probably in marine sediments in general. This conclusion is bolstered by the lack of any significant enrichment of silver in manganese nodules (Baturin, 1988). The lack of association of Ag with Mn02 is likely due to the negative charge of silver chloride complexes in seawater, which inhibits adsorption. 5.2.2.2 Fe Oxides In a similar manner to Mn, Fe is released from sediments under anoxic conditions (as Fe + 2) and is reprecipitated as Fe oxyhydroxides under oxic conditions. Iron concentrations in detrital material are higher than for Mn due to the common presence in sediments of such iron-rich minerals as chlorite (Calvert, 1976), which is a dominant component of the fine-grained fraction in the Strait of Georgia deposits (Pharo, 1976). Consequently concentrations of Fe in the sediments tend to be controlled by both texture and mineralogy (Figures 4.23 and 4.24), and as a result, Fe/Al ratios are equivocal in indicating the presence of iron oxide phases in sediments dominated by chlorite-rich detrital material. Thus, another element that is more specifically associated with Fe oxides in sediments but is rare in the detrital fraction, such as phosphorus, may provide a more useful tracer for the presence of Fe oxides. Although phosphorus in sediments is associated with both detrital material (as, for example, in apatite) and organic matter (Lucotte and d'Anglejan, 1983; Ormaza-Gonazalez and Statham, 1991) its occurrence in these phases is typically very minor. Phosphorus is also found in sewage wastes, where its concentration can be more significant due to the presence of detergents and fertilizer residues. However there is no discernable P enrichment in Georgia Strait sediments north of the outfall where silver is strikingly enriched. Indeed, ratios of P/Al are similar to the average shale value (~ 0.07 x 10^) over most of the Strait. Hence, the addition of sewage does not seem to have expressly enhanced the P concentration in sediments on the delta foreslope. P/Al ratios are higher in near-surface deposits in the deep basin, where diagenetic manganese enrichments are observed. Given the known affinity of FeOOH for P04~3, the high P /Al values imply that Fe oxide phases are indeed enriched in the oxic surface sediments in the deep basin of the Strait. Although organic carbon concentrations are are also higher in these sediments, there is no obvious surface enrichment of Corg implying that organic P is not responsible for the high P /Al ratios. 101 Thus, enrichments of P at the surface of several cores are consistent with the presence of Fe oxides, for example, in cores A O , and particularly in SG55, SG4 and AG54 (Figure 4.25). In core AG54, the increases in P/Al are matched by increases in Fe/Al (Figures 4.26 and 4.25). Despite this, the absence of commensurate enrichments of silver in the same cores (Figure 5.5) indicates that Fe oxides cannot be an important host of silver in Georgia Strait sediments. 5.2.2.3 Organic Matter and Sulphides Samples analyzed for this study from the anoxic sediments of Saanich Inlet, an intermittantly anoxic basin, show enriched silver concentrations of ~ 270 ppb (Table A3.10, Appendix 3). Such enrichments are of natural origin (Koide et al., 1986) and can be attributed to the reaction of dissolved Ag with dissolved HS", producing the highly insoluble Ag2S. Thus, given the low solubility of Ag2S, evidence that the silver-bearing Iona effluent comes in contact with the bottom sediments on occasion (Bertold and Stewart, written communication, 1996), and the expected anoxic character of the sediments under the plume, it is possible that dissolved silver may precipitate diagenetically as the sulphide in the near-outfall deposits. A simple calculation, however, shows that silver addition by this process is insignificant. Using a high dissolved Ag value for contaminated seawater (~ 300 pM; Sanudo-Wilhelmy and Flegal, 1992), which is similar to the maximum value of silver present in the Iona effluent (~ 74, 000 pM) (GVRD, 1994) after an initial rapid dilution of ~ 275 times (GVRD, 1989a), and given a discharge rate of 14 m3/s (GVRD, 1994) the amount of dissolved Ag introduced into the Strait in one year is ~ 7.14 x 10^ g. If all of this Ag was precipitated into the top 1 cm layer within an area defined by the 400 ppb contour, and given a sediment grain density of 2.6 g/cm^, an increase of only ~ 20 ppb over the natural sedimentary background concentration would occur. This increase is minor compared to the actual values found near the outfall which range from ~ 300 ppb to 700 ppb, some three to seven times the background. Thus, precipitation of silver sulphide cannot realistically account for the observed silver enrichments on the foreslope. Indeed, all that is needed to account for the Ag concentrations observed on the foreslope is for the sediments to consist of < 2% of sewage particles, which contain, on average, 27 ppm Ag (Ravizza and Bothner, 1996). Likewise Morel et al. (1975) calculated that the addition of ~ 1% sewage particles can account for the trace metal concentrations found in sediments near an outfall off the coast of California. 103 Adsorption experiments show that silver is strongly adsorbed to organic material (Krauskopf, 1967; Chapman et al., 1988) however this may be due to the presence of silver as A g + rather than negatively charged silver chloride complexes. Adsorption of silver to sediments is greater in low salinity water where A g + dominates than in seawater (Sanders and Abbe, 1987; 1989). In fact most silver adsorbed to sediments at low salinity is released at higher salinities. In contrast, only a small amount of silver adsorbed to phytoplankton at low salinity is released when the material is placed in solution of higher salinity. Silver is either incorporated into the cells or is strongly adsorbed (Sanders and Abbe, 1987; Reinfelder and Fisher, 1991; Wen-Xiong and Fisher, 1996; Luoma and Phillips, 1988) which suggests that organic material is a likely host for silver in sediments via the uptake and/or adsorption of silver by organisms rather than organic coatings or detrital organic material. 5.3 Other Tracers 5.3.1 Stable Isotopes of Carbon and Nitrogen S ^ N and 8l3c o rg isotopic signals are typically used to characterize marine and terrestrial organic inputs to coastal marine sediments (Owens and Law, 1989; Thornton and McManus, 1994; Shultz and Calder, 1976; Sackett and Thomson, 1963). Indeed, the distributions of S ^ N (Figures 4.6 and 4.8) and S^Corg (Figures 4.7 and 4.9) are consistent with the mixing of terrestrial organic material and marine organic material in the southern Georgia Strait. These indicators have also been used successfully to indicate the presence of sewage in coastal sediments. The use of these markers requires that sewage wastes have a distinct isotopic signal compared to the receiving environment. Sewage is characterized by isotopic ratios that are similar to terrestrial material, which limits the use of these markers in environments receiving significant terrestrial inputs (Sweeney and Kaplan, 1980a; 1980b; Sweeney et al., 1980; Peters et al., 1978; Burnett and Schaeffer, 1980). Sediments in the Strait of Georgia are dominated by input from the Fraser River sediments and consequently isotopes of carbon and nitrogen are unable to indicate the distribution of sewage in the delta-front sediments, as shown in Figures 4.7 and 4.9. Even in the best case scenario where sewage inputs would be deposited in sediments dominated by marine organic material the signal would not change significantly with the addition of only a few percent sewage particles:- .-Isotopically heavier values for both 8 ^ N (~ 6%c) and 5l3co rg (~ -2l%o) are found in the deep basin of the Strait and these ratios are similar to those reported for marine organic 105 material which has a 8 1 5 N of about 5-6%0 (Montoya, 1994) and a 5 1 3 C 0 r g of ~ -19%0 (Sackett and Thomson, 1963). Anomalously high S^Corg values found on Sturgeon Bank suggest that inputs from marsh plants and seaweeds are present. Seaweeds such as the benthic macrophytes Ulva lactuca and Entomoropha sp. have heavy 8 ^ C 0 r g ratios of about -10%o to -21%o (Simenstad and Wissmar, 1985) and occur on the bank (Luternauer and Murray, 1973). Such heavy values are attributed to lower fractionation of the isotopes during diffusion of CC»2 into the plants (Lajtha and Michener, 1994). Other factors which can affect the S ^ N signal in sediments, in addition to the general terrestrial or marine provenance of organic matter, include the isotopic value and concentration of nitrate used by primary producers and the number of trophic levels through which the deposited organic material has passed, each level enriching 8 ^ N by about 3.5%o (Thornton and McManus, 1994; Minigawa and Wada, 1984; Farrel et al., 1995; Altabet and Francois, 1994). With respect to 8^0, the C 0 2 concentration, the carbon fixation pathway, and the types of phytoplankton species can be important (Rau et a l , 1991; Hinga et al., 1994; Lajtha and Michener, 1994). However, none of these various influences is thought to be particularly important in the Strait of Georgia, in the face of the obvious overriding control of terrestrial inputs via the Fraser River, and they will therefore not be discussed in detail here. Given the dominance of the sedimentary load from the Fraser on the isotope ratio distributions near the Iona outfall, it can be concluded that neither 8l3co rg and 8 ^ N in sediments of the Strait of Georgia are useful as sewage tracers. In support of this conclusion, C/N weight ratios in foreslope sediments similarly show little evidence of being influenced by the input of sewage. Ratios on the delta and foreslope are generally > 10 and indicate the presence of mostly terrestrial material. Terrestrial material such as wood, bark, and twigs is relatively deplete in nitrogen but replete in carbon due to the secessity of plants on land to have a vascular structure to counter gravity. Thus, the C / N ratio in terrestrial organic materials ranges typically from 20-200 (Emerson and Hedges, 1988). In contrast, lower ratios in the central basin of the Strait of ~ 9 are more indicative of marine organic material (Figures 4.17 and 4.18). Marine organic matter such as phytoplankton contains a much higher content of nitrogenous compounds and is therefore characterized by a ratio of ~ 6 (Francois, 1987; Drysdale, 1990). Thus, the C /N distribution plot (Figure 4.17) even in the central basin of the Strait where the lowest ratios are only ~ 9 implies that a significant amount of terrestrial material is present. This is consistent with the observation by Parsons et al. (1970) that the amount of terrestrial material supplied to the Strait is about the same or more than the amount of marine organic matter produced in situ. 106 5.3.2 Trace Metals (Cu, Pb, and Zn) Trace metal values for Cu, Pb, and Zn on the foreslope before and after the discharge of effluent along the foreslope (i.e. prior to and post-1988) show no change in concentration (GVRD, 1996; Grieve and Fletcher, 1976). Concentrations of these metals in Strait of Georgia sediments are largely controlled by variations in sediment texture (Grieve and Fletcher, 1976; Feeney, 1995). Higher metal values are found in fine-grained sediments that deposit near shore and in the deep basin, while lower concentrations characterize the coarser grained deposits on the delta. The control of sediment texture on these metal levels is reflected in the similarity of their distributions to that of Si /Al (Figures 4.26,4.28, 4.30 and 4.12). Higher concentrations of these metals in the fine-grained fraction (Calvert, 1976; Grieve and Fletcher, 1976) result from the adsorption of positively charged metals to negatively charged clay minerals found in fine-grained muds. Trace metals such as Pb, Cu, and Zn show no enrichments that can be specifically ascribed to sewage in surface sediments of the Strait of Georgia (Figures 4.26, 4.28 and 4.30). Only minor enrichments of these metals are observed on Sturgeon Bank below the sediment surface where the silver values are the highest found in the study (~ 3.3 ppm) (Figure 4.32). Trace metals such as Pb, Cu and Zn have limited utility as tracers of sewage not only because these metals have high natural contents in detritus but also because other anthropogenic sources of these metals are significant. For example, Cu and Zn enrichments are observed in sediments contaminated with mine tailings in Howe Sound (Drysdale, 1990), and these tailings are a source of particulate Cu and Zn into the Strait (Macdonald et a l , 1991). Furthermore a greater impact is observed on lead contents as a result of the addition of Pb derived from gasoline and transported via the atmosphere (Veron et al., 1987; Macdonald et al., 1991). Indeed vertical profiles of lead in cores from the Strait (SG4) and Burrard Inlet (AG54) show high lead enrichments about 10 cm below the core surface. In more recent sediments a decrease in the Pb/Al ratio reflects the phasing out of Pb in gasoline which has occurred over the last two decades. 5.4 Past and Present Sedimentary Conditions 5.4.1 Historical Influences on Sturgeon Bank Before the construction of the Iona sewage treatment plant in 1962 the McDonald slough was open which prevented fine grained material from being deposited near site A O 107 (Grieve and Fletcher, 1976). This is reflected in core A O by the coarse material at depth which contains low silver concentrations. A slight increase in the silver content in the overlying sediments is consistent with the closing of the slough in 1962 to provide access to Iona Island. The closure resulted in the deposition of fine-grained material as strong currents from the river were no longer present and the area became a low energy environment. The subsurface silver peak in the core (Figure 4.32) can be attributed to the direct discharge of sewage into the subtidal zone during the period of 1962-1988. The decreased sewage inputs that began in 1988 account for the decline in the Ag content that is observed near the top of the core. High silver values (~ 3.3 ppm) found below the surface in core A O may have contributed to the azooic conditions that formed in this area. Concentrations greater than about 1-2 ppm Ag are considered to be above the threshold level for coastal environments (Bothner et al., 1994). The lower levels found near the surface of core A O may have allowed the repopulation of certain organisms to the area that has been observed recently (Arvai, 1997). 5.4.2 Steady-State Conditions In contrast to the variable profile of silver in core A O , which reflects historical changes in deposition, areal distributions of silver in the Strait of Georgia sediments have been relatively constant in recent years (Figure 4.3a). Indeed, concentrations of silver in samples taken from the same location but over a two year period have similar silver concentrations (Table A4.9, Appendix 4). Silver distributions in the upper portions of sediment cores from the Strait exhibit vertical profiles (Figure 4.3a) which implies that a balance has been reached between the deposition of sewage particles and natural sediments supplied by the Fraser River. The profile in core A G 17 also indicates that silver values are not increasing in the enriched zone on the foreslope. In general, supply from the Fraser swamps inputs from Iona which is reflected in the distribution of Cu, Pb, Zn and the isotopes, which are clearly dominated by detrital inputs on the delta and foreslope. At present, there is no indication of environmental degradation on the foreslope (GVRD, 1996). 108 Chapter 6. Summary and Conclusions The results of this thesis show that silver distributions in modern sediments of the Strait of Georgia are controlled primarily by sewage inputs. Patterns of high silver concentrations are consistent with the transport and deposition of silver enriched fine-grained sewage particles from the Iona sewage treatment plant. Effluent from this plant was discharged directly onto Sturgeon Bank from about 1963 to 1988 and from 1988 to the present from the deep outfall. Minor silver enrichments are found throughout the deeper waters of the Strait. Dating by Pb-210 in a core from the axial trough indicates that increases in silver in the deep basin started sometime before 1950. Silver concentrations are also affected by sediment grain size. Coarse-grained Ag-poor material effectively dilutes the silver signal in areas where high amounts of sand are accumulating, for example, on Sturgeon Bank and east of the outfall on the foreslope. Potential hosts of silver in marine sediments were examined through comparative analysis of silver to other elements. Surface enrichments of Mn/Al , Fe/Al and P /Al in sediment cores from the Strait are not paralleled by Ag enrichments, which indicates that M n oxides and Fe oxides are not significant hosts for silver in coastal sediments. However silver enrichments occur naturally under anoxic conditions, presumably by the precipitation or coprecipitation of the silver sulphide, but this mechanism cannot account for the high silver values on the foreslope. The input of sewage clearly remains the primary control. In contrast to silver, the distributions of b^N and S^Corg show no signals that can be attributed to sewage inputs. Rather, the distributions of these isotopic ratios reflect the relative amounts of terrestrial and marine organic material deposited in the area. Thus, these markers are ineffective as indicators of sewage inputs. Similarly, the distributions of the trace metals Cu, Pb, and Zn show no signals in surface sediments associated with sewage input. Only minor enrichments are observed below the sediment surface on Sturgeon Bank in an area severely impacted previously by sewage input. Significant amounts of Fraser River sediments on the foreslope effectively dilute the sewage particles such that there is no sign of enrichment of the sewage-borne trace metals. Silver, on the other hand, has such a high enrichment in sewage wastes compared to its detrital value that a small addition of sewage particles leads to significant enrichments. Thus silver is an extremely sensitive indicator of sewage wastes in coastal sedimentary environments and is useful for determining the direction of transport and the site of sediment deposition of sewage particles. High inputs of Fraser River sediments into the foreslope and Strait relative to the comparatively low input of sewage appear to be sufficient to ensure that sedimentary silver 109 concentrations are not increasing. This is shown by the vertical distribution of silver in modern sediments in cores from the Strait and the foreslope, and by invariant concentrations measured over at least two years in surface sediments on the delta front. 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Cores VG1-VG5 were collected on August 24, 1994; cores SG1-SG32 and SG33-SG59 were collected on May 23-25, 1995; and cores AG1-AG9, AG11, AG13-AG59 and grab samples AG10gs-AG13gs were collected on July 30-31, 1996. Core and surface samples from Sturgeon Bank were collected at low tide on July 12, 1995 (AO, A12, K A 1 , K A 2 , W6, W7, and W8) and on July 2,1996 (AO-96, A10, A12-96 and HC1 to HC17). Core samples were taken at sites A O , A12 and A10 only. A surface sample at A14 and an additional two cores from Roberts Bank (A10 and BPt-1) were collected on July 2,1996. Sample locations are shown in Figs. 1.1 and 1.2. Sampling sites on the mudflats of Sturgeon Bank and Roberts Bank were accessed by the Canadian Coast Guard hovercraft. Sampling locations, core lengths and water depths are listed in Tables A2.1 and A2.2, Appendix 2 and sample descriptions in Tables A3.1 and A3.2, Appendix 3. In addition to the cores collected for this study, an additional four cores (5903, 5904, 5911, and 5912) were collected by the Institute of Ocean Sciences in 1993 and another 22 surface collected by Simon Fraser University in 1995. Sample locations and descriptions are available Table A2.3, Appendix 2 and Table A3.3, Appendix 3. Cores from Strait of Georgia were collected with a lightweight gravity corer (Pedersen et al., 1985) designed to minimize the disturbance of the sediment/water interface. About 20 kg of lead weight was added to the corer to increase the penetration depth of the core barrel into the sediment. A butryate core barrel of 8 cm inner diameter and 8.8 cm outer diameter was used. The gravity corer was lowered to about 5 m off the sea floor and allowed to free fall into the sediments. Although the addition of weight increases the potential for disturbance at the sediment/water interface, the relatively clear water at the top of the sediment in the core barrel for most core samples indicated that disturbance of the sediment/water interface was minimal. Full length cores from from Sturgeon Bank and Roberts Bank were collected by inserting a 50 cm long core barrel into exposed sediments and removing the core barrel with a shovel. For surface samples a 5 cm long core ring was inserted into the exposed sediment and removed. Gravity cores were extruded on board after the supernatant was carefully removed so as not to disturb the sediment interface. Cores from the mudflats were extruded in situ or on 125 the side deck of the hovercraft. For all cores, sediment was extruded from the barrel and sectioned as follows: 1 cm for the top 10 cm, 2 cm for the next 20 cm and 5 cm to the end of the core. Cores were sampled to various lengths and remaining material was discarded. Core rings of 1 cm, 2 cm and 5 cm were used to measure the sediment interval. Sample intervals were separated from the core by pulling a plastic line between the top of the core barrel and the core ring inserting an acrylic sheet below the ring and removing the sheet with the sample on top. The edges of the sediment wafer were removed with a plastic spatula and the sample placed in labelled ziplock bag and frozen. The rings, spatula, and acrylic sheet were rinsed with distilled water before reusing for the next sample. Grab samples were collected with a Shipek sampler with a stainless steel bucket. This device was used at shallow locations in silt/sand sediment where the sediment would not remain in the gravity corer. Some fine sediment is lost during sampling with the grab sampler. A 2 cm core ring was pushed into the collected sediment, and the sub-sample was removed and frozen in a ziplock bag. Frozen bulk samples were dried in a Edwards 4K Modulyo freeze-drier. Dried samples were subsequently ground manually using a mortar and pestle and placed in labelled plastic vials. A 1.2 Inorganic Carbon Sediments were analyzed for inorganic carbon by coulometry using coulometrics 5030 and 5010 coulometers. Approximately 30-80 mg of dry, ground sediment was accurately weighed, placed into a glass test tube attached to a carbonate carbon apparatus, and acidified with ~ 5 ml of 10% hydrochloric acid. Evolved CO2 was transported in C02-free air to an AgN03-filled scubber to remove product gases such as HC1, CI2, SO2, and N O x that could potentially interfere with the analysis. CO2 generated from the sample was adsorbed in a coulometric cell containing ethanolamine and a colourimetric indicator. Ethanolamine reacts with the CO2 to form a strong titratable acid via CO2 + HO-CH2-CH2-NH2 — > HO-CH2-CH2-NH-COOH. The formation of the acid causes the blue indicator to fade and consequently causes the transmittance of a light beam directed through the cell to a detector to increase. A current is automatically switched on and a base is generated electrochemically at a silver electrode to neutralize the acid. Hyroxide ions (OH") are generated at a silver electrode by the reduction 126 of water: A g u —> A g + + e" H2O + e" —> 1/2H2 + OH-As the acid is neutralized by the base: HO-CH2-CH2-NH-COOH + OH" —> HO-CH2-CH2-NOO- +H2O the solution returns to its original color and the current is automatically turned off. The total current required for the titration is integrated electronically and displayed as ug C. Inorganic or carbonate carbon (%Cmorg) is calculated using the ug C as follows: %Qnorg= Csample - ug Cblank) * 100 sample weight (ug) Blanks and a CaC03 standard were run at the start and frequently during each batch of analyses. Mean blank values for coulometers 5010 and 5011 were 3.39 ug C and 4.30 ug C, respectively. The mean values of the CaC03 (12.00% C) standard were 11.93% and 11.85%, respectively. Approximately 10 mg of CaC03 standard was used for these accuracy checks. A set of six sub-samples from a single sediment sample (SG4 30-35) with 0.72 weight% CaC03 yielded relative standard deviations (Is) of 14.9% and 8.3% for models 5010 and 5011, respectively (Table A l . l ) . A1.3 Total Carbon, Nitrogen, and Sulphur Total carbon (C), nitrogen (N) and sulphur (S) were determined by gas chromatography using a Carlo-Erba CNS analyzer (model NA-1500). Approximately 20-50 mg of sediment sample was added to a tared tin cup containing some vanadium pentoxide (V2O5). Air was removed from the tin cup by crimping and compacting the tin cup. At this point an accurate weight of the sample in the cup was determined with a Mettler microbalance. Weighed tin cups were placed in a tray of up to a maximum of 38 samples and kept in a dessicator until analysis. For each tray 2 blanks and 10 standards were prepared. 127 Table A 1.1 Inorganic carbon analytical precision determined by analyzing six sub-samples from a single homogenized sample for each of the two coulometry systems. Inorganic carbon values are in weight percent. Model 5010 Model 5011 Sample (n=6) % Cinorg Sample (n=6) % Cinorg SG4 (30-35)a 0.084 SG4 (30-35)g 0.114 SG4 (30-35)b 0.085 SG4 (30-35)h 0.103 SG4 (30-35)c 0.081 SG4 (30-35)i 0.106 SG4 (30-35)d 0.074 SG4 (30-35)j 0.101 SG4(30-35)e 0.111 SG4 (30-35)k 0.091 SG4 (30-35)f 0.083 SG4 (30-35)1 0.091 Average 0.086 Average 0.102 Standard Deviation 0.013 Standard Deviation 0.008 RSD (%) 14.87 RSD (%) 8.28 128 Standards included 5 samples of sulfanamide (16.27% C, 41.84% N and 18.62% S), 2 samples each of the marine reference standards PACS-1 (3.69% C and 1.32% S) and MESS-1 (2.99% C and 0.72% S) and 1 sample of BCSS-1 (2.19% C and 0.36% S). Values are listed as weight percent. Weights used for the standards ranged from >0.05-2.0 mg for sulfanamide and 6.0-30.0 mg for the marine reference standards. Blanks consisted of tin cups containing an small amount of V2O5 which was added to each sample and standard to enhance the combustion of the sample in the analysis. Tin cups were added to a vertical quartz combustion tube, heated to 1000 °C, and flash combusted in a temporarily enriched atmosphere of oxygen. A pulse of high purity oxygen was introduced into the helium carrier gas that flowed constantly through the tube. Vanadium pentoxide acted as an oxygen donor to promote combustion and as a catalyst to convert sulphates to S02- Released combustion products (CO2, H2O, N O x and SO2), transported along in the carrier gas, were quantitatively oxidized in a section of WO3 on pure aluminum. Excess oxygen was removed and nitrogen oxides reduced to N2 in a section of copper heated to 650 °C. Quartz wool was placed before the copper to reduce the temperature of the gases. Water was removed by a filter containing magnesium perchlorate. Product gases N2, CO2 and SO2 were separated on a chromatographic column, heated to 80 °C, and detected by a thermal conductivity detector. The detector consists of a heated wire connected to a resistance measuring device. Detection is based on the differences in thermal conductivity of the product gas and carrier gas which results in heat being conducted away from a heated wire at different rates. A change in the temperature of the wire causes a change in the electrical resistance of the wire and it is this change in resistance that is used to detect the presence of a product gas (Robinson, 1995). The output signal is proportional to the concentration of the gas in the mixture. Calibration curves for nitrogen, carbon, and sulphur were prepared by plotting the amount of nitrogen, carbon, or sulphur in ug against the peak area in microvolts times seconds (micV*s) for the standards and blanks. Micrograms of the elements in the standards were calculated from the following equation, nitrogen is used as an example: mg Nstandard = weightstandard (mg) * % N 1000 100 Calibration curves were used to determine the percent N , C or S in the sample from the peak areas as follows: %Nsample = [(counts of N * slope) + intercept] * 100 weightsample * 1000 129 where the sample weight is in mg and the counts in micV* s. Analytical precision was determined by analyzing three sets of 6 sub-samples. Six sub-samples were taken from three different samples A O 4-5 cm, SG4 30-35 cm and AG54 30-35 which contain 0.85%, 1.60% and 1.36% by weight of carbon; 0.067%, 0.15% and 0.11% by weight of nitrogen; and 1.01%, 0.33% and 0.31% by weight of sulphur, respectively. The relative standard deviations for total carbon are 10.6%, 0.29% and 1.5%; for nitrogen 4.0%, 0.82% and 2.7%; and for sulphur 4.7% , 1.5% and 4.5%, respectively (Table A1.2). An average detection limit six times the standard deviation of the blank was determined to be -0.01% for C and N . This detection limit is similar to that reported by Verardo et al. (1990) for carbon. Organic carbon was determined by subtracting inorganic carbon from total carbon. Values for total carbon, total nitrogen, total sulphur, organic carbon were corrected for dilution by seasalt and are presented in Tables A4.1 and A4.5 in Appendix 4. A1.4 Major (Fe, Mn, Ti, Ca, K, Si, Al, Mg, P, Na) and Minor (Ba, Co, Cr, Cu, Mn, Ni, Pb, Rb, Sr, V, Y, Zn, Zr, I, Br, and Mo) Elements Major and minor elements were determined by X-ray fluorescence using an automated Philips PW 1400 X-ray fluorescence spectrometer controlled by a DEC PDT 11 computer. The analytical and sample preparation methods used followed those of Calvert et al. (1985). Components and instrument settings for each element are listed in Tables A1.3a and A1.3b. International rock standards were used to calibrate the spectrometer and to monitor the accuracy of the analyses. Measured values are listed in Tables A1.4, A1.5, A1.6, and A1.7 and are compared with the recommended values of Abbey (1983). The relative standard deviation of the measurements was determined from the analysis of various standards and was typically < 10% for major and minor elements except for Y , Pb and N i (Tables A1.8a, A1.9a, A 1.10 and A 1.11). Relative standard deviations of the elements determined using six sub-samples from given sediment samples from Howe Sound (Drysdale, 1990) and Sturgeon Bank (Feeney, 1995) are listed in Tables A1.8b and A1.9b. For elements with analytical lines of wavelengths shorter than the absorption edge of the heaviest matrix element (Fe), or atomic numbers greater than 27, the mass absorption coefficient at a given wavelength is inversely proportional to the intensity of the Compton scattered radiation of the primary X-ray beam (Reynolds 1963). For these elements, the analyte line was corrected for matrix adsorption using the amplitude of the Compton-scattered part of the incident Rh Ka radiation. 130 Table A 1.2 Total carbon, nitrogen, and sulphur analytical precision determined on six sub-samples of a given sample. Values are in weight percent. RSD=relative standard deviation. Sample Ctot Ntot Stot A O 4-5 0.78 0.064 1.01 0.84 0.068 1.03 0.81 0.067 1.03 0.80 0.063 0.96 1.03 0.069 0.95 0.87 0.070 1.07 Average 0.85 0.067 1.01 Standard 0.091 0.0027 0.047 Deviation RSD (%) 10.6 4.04 4.69 SG4 30-35 1.61 0.15 0.33 1.60 0.15 0.33 1.60 0.15 0.34 1.61 0.15 0.33 1.60 0.15 0.34 1.60 0.15 0.34 Average 1.60 0.15 0.33 Standard 0.0047 0.0012 0.0050 Deviation RSD (%) 0.29 0.82 1.50 AG54 30-35 1.33 0.11 0.30 1.34 0.11 0.29 1.34 0.11 0.30 1.37 0.11 0.30 1.36 0.11 0.31 1.39 0.11 0.33 Average 1.36 0.11 0.31 Standard 0.0203 0.23 0.014 Deviation RSD (%) 1.50 2.68 4.48 131 Table A1.3a) X R F instrument conditions for major elements; b) X R F instrument conditions for minor elements. a) Element Atomic Tube Crystal Counter Peak 2q (O) Bkg 2q (O) Collima Number k V raA -tor Si 14 60 40 T F 32.23 +2.3/-1.2 C A l 13 60 40 T F 37.88 +1.00 C Fe 26 60 40 L F 63.14 -1.60 c Ti 22 60 40 L F 86.35 +3.0/-1.0 c Ca 20 50 10 L F 113.34 +1.40 c K 19 60 40 L F 136.76 +2.00 F Mn 25 50 20 L F 63.14 -0.86 C Mg 12 30 60 T F 45.21 -1.20 C P 15 30 60 G F 141.12 -1.50 c b) Element Atomic Tube Crystal Counter Peak 2q (°) Bkg 2q (O) Collima Number kV mA -tor Ba 56 60 40 L F 87.19 +1.20 F Co 27 60 40 L F 77.90 +0.54/-0.54 F Cr 24 60 40 L F 69.52 +1.00 C Cu 29 60 40 L F/S 45.00 -0.62 F N i 28 60 40 L F/S 48.66 +1.2/-0.6 F Pb 82 60 40 L F/S 28.29 +0.5/-0.5 F Rb 37 60 40 L S 26.66 +0.4/-0.9 F Sr 38 60 40 L s 25.20 +0.6/-0.6 F V 23 60 40 L F 77.14 +4.0/-2.6 C Y 39 60 40 L S 23.83 +0.6/-0.6 F Zn 30 60 40 L F/S 41.78 0.72 F Zr 40 60 40 L S 22.56 +0.74/-0.74 F Na 11 30 60 T F 55.25 +3.4/-1.7 C Mo 42 60 40 L S 28.855 +0.4/0.0 F I 53 60 40 L S 12.35 +0.60/-0.60 F Br 35 60 40 L F/S 29.935 +1.1/-1.1 F A l l elements measured on the Ka line, except Ba and Pb (Lb) Crystals: L=lithium fluoride (200); T=thallium acid phthalate; G=germanium Counters: F=flow using 90% Ar and 10% CH4; S=scintillation Collimators: C=coarse (480 pjn); F=fine (160 um) 132 Table A 1.4 Accuracy of X R F analysis for major elements. Measured values are compared to the recommended value (R). Values are in weight percent of the oxide. Standard Fe Mn Ti Ca K Si A l Mg P Na JA2 JA2 JA2 JA2 4.34 4.34 4.34 4.41 0.08 0.08 0.08 0.08 0.4 0.4 0.4 0.41 4.51 4.51 4.45 4.53 1.54 1.51 1.56 1.47 25.73 25.68 25.8 26.63 8.24 8.36 7.68 8.24 4.6 4.51 4.63 4.64 0.06 0.07 0.07 0.08 2.71 2.64 2.72 2.43 JA2 (R) 4.34 0.08 0.4 4.5 1.5 26.37 8.16 4.58 0.06 2.31 A G V A G V A G V A G V 4.85 4.83 4.85 5.04 0.08 0.08 0.08 0.08 0.64 0.64 0.64 0.68 3.54 3.52 3.5 3.69 2.51 2.47 2.49 2.52 27.48 27.51 27.56 29.96 9.49 9.44 8.86 9.81 0.93 0.98 0.92 1.03 0.21 0.21 0.2 0.25 2.88 3.14 2.97 3.55 A G V (R) 4.73 0.07 0.63 3.53 2.42 27.48 9.07 0.92 0.21 3.16 JB3 JB3 JB3 8.24 8.24 8.34 0.14 0.14 0.15 0.85 0.85 0.86 7 7.02 7.1 0.61 0.62 0.62 23.86 23.81 23.9 9.3 9.48 8.97 3.19 3.21 3.11 0.14 0.14 0.13 1.71 2.05 2.1 JB3 (R) 8.27 0.14 0.86 7 0.65 23.82 9.01 3.13 0.13 2.03 JB2 JB2 JB2 10.04 10.03 10.06 0.17 0.17 0.17 0.7 0.7 0.7 7.08 7.1 7.1 0.34 0.36 0.34 24.95 24.85 24.91 8.08 8.11 7.73 2.84 2.71 2.8 0.04 0.04 0.04 1.72 1.9 1.79 JB2 (R) 9.97 0.17 0.71 7.02 0.35 24.89 7.75 2.79 0.04 1.51 B E N B E N B E N 9.04 9.04 9.04 0.15 0.15 0.15 1.58 1.58 1.58 10.12 10.13 10.02 1.17 1.17 1.2 18.19 18.2 18.36 5.36 5.41 5.03 7.98 8.02 7.98 0.46 0.46 0.46 2.13 2.29 2.16 B E N (R) 8.98 0.15 1.56 9.91 1.15 17.86 5.33 7.93 0.46 2.36 JA3 JA3 4.64 4.64 0.08 0.08 0.41 0.42 4.55 4.46 1.15 1.17 29.15 29.27 8.76 8.03 2.24 2.29 0.07 0.07 2.49 2.29 J A3 (R) 4.62 0.08 0.42 4.46 1.17 29.11 8.24 2.24 0.05 2.37 J B I A 6.25 0.11 0.76 6.58 1.14 24.69 7.68 4.84 0.13 1.77 J B I A (R) 6.33 0.11 0.77 6.65 1.16 24.5 7.65 4.72 0.11 2.03 JG3 2.56 0.05 0.3 2.64 2.15 31.34 8.1 1.14 0.07 2.83 JG3 (R) 2.58 0.05 0.29 2.64 2.19 31.45 8.19 1.08 0.05 2.94 133 Table A 1.5 Accuracy of X R F analysis of minor elements. Measured values are compared the recommended value (R). Values are in ppm. Standard Zr Y Sr Rb Pb Zn Cu Ni Co Mn V Cr Ba Na AGV 240 18 646 69 34 84 60 8.8 12 799 144 17 1227 3.63 AGV 275 26 772 79 45 100 68 12 12 891 142 20 1308 3.79 AGV 244 20 633 64 40 89 64 10 15 769 133 18 1197 3.59 AGV 234 21 635 62 36 84 58 7.8 15 800 132 19 1240 3.66 AGV 240 25 634 63 36 84 67 13 16 782 132 19 1206 3.63 AGV 245 15 635 64 24 86 62 11 15 793 137 20 1238 3.59 AGV 232 24 640 63 23 85 64 11 15 789 147 16 1206 3.76 AGV (R) 227 20 662 67 36 88 60 16 15 728 121 10 1226 4.26 G2 320 18 465 163 26 86 18 1 6 240 58 11 1956 3.97 G2 318 17 470 169 21 87 14 0 8 223 49 10 1841 3.90 G2 321 18 472 170 37 87 14 0 5 226 50 11 1891 3.94 G2 314 18 469 166 22 85 18 2 7 228 51 9 1870 4.11 G2(R) 309 11 478 170 30 86 11 3 5 265 36 9 1882 4.08 NIMG 265 132 5.5 320 42 48 6.3 25 6 128 2 1 35.4 3.27 NIMG 263 131 7.5 304 40 49 5.4 27 6 127 -17 1 33.2 3.29 NIMG 261 129 11 306 54 50 3.4 30 6 120 -17 -1.7 15.3 3.25 NIMG 262 135 12 298 37 49 7 27 6 129 2 2.2 27.3 3.35 NIMG (R) 300 143 10 320 40 50 12 8 4 — 2 12 120 3.36 W2 92 20 190 19 12 78 108 62 37 1223 259 100 189 2.35 W2 86 19 189 28 14 77 105 64 43 1204 248 98 184 2.30 W2 88 17 179 16 24 71 104 66 39 1227 263 97 176 2.41 W2 (R) 94 24 194 20 9 77 103 70 44 1300 262 93 182 2.14 MRG 101 16 271 0.1 16 198 131 187 89 1111 527 483 282 0.61 MRG 101 10 264 8 4.6 191 133 189 92 1098 541 469 281 0.6 MRG 99 9 264 5 6.8 192 133 190 92 1083 525 467 282 0.59 MRG (R) 108 14 266 9 10 191 134 153 87 1320 526 430 61 0.74 JG2 92 87 17 291 23.1 15.4 -4.3 14.9 7.1 145 -17 -2.5 -13 3.62 JG2 93 92 10 301 29.1 14 -3.9 16.9 5.8 141 -17 -1.9 -17 3.67 JG2* 97 89 16 297 32.8 12.7 0.4 2.1 4.3 — 3 7.6 67 3.54 BEN 271 22 1300 53 21 115 75 283 57 1396 273 362 1121 3.79 BEN (R) 265 30 1370 47 4 120 72 267 61 1548 235 360 1025 3 JB3 91.3 21 394 18 13.5 93 200 28.3 25.9 1343 386 62.7 299 2.8 JB3 (R) 99.4 28 395 13 5.5 106 198 38.8 36.3 — 383 60.4 251 1.1 GSP 516 38 241 254 44 109 38 13 9 264 64 10 1235 2.7 GSP (R) 500 29 240 250 54 105 33 9 7 326 54 12 1300 2.8 134 Table A1.6 Accuracy of X R F analysis of I and Br. Measured values are compared to the recommended value (R). Values are in ppm. Standard I Br IBR1 1035 1131 IBR1 1019 1119 IBR1 1031 1128 B3R1 1024 1112 IBR1 1021 1127 D3R1 1072 1121 IBR1 (R) 1028 1173 IBR2 521 661 IBR2 511 630 D3R2 511 621 IBR2 514 609 IBR2 506 617 IBR2 523 720 IBR2 (R) 514 587 IBR3 252 268 IBR3 252 251 IBR3 (R) 257 294 IBR4 135 168 IBR4 124 157 IBR4 119 146 IBR4 120 143 IBR4 120 144 IBR4 133 167 IBR4 (R) 128 147 IBR5 60 73 IBR5 61.8 71.2 D3R5 58.2 69.9 IBR5 55.1 71.5 IBR5 (R) 64.3 73.5 IBR6 26.3 26.1 D3R6 29.2 22.9 B3R6 28.7 23.2 D3R6 28 23 IBR6 (R) 32 37 IBR7 13.6 0.7 IBR7 13.1 2 IBR7 (R) 16 18 135 Table A 1.7 Accuracy of X R F analysis for Mo. Measured values are compared to the recommended value (R). Values are in ppm. Standard Mo GXR1 19.9 GXR1 19.4 GXR1 20.3 GXR1 21 GXR1 16.4 GXR1 16.5 GXR1 (R) 18 GXR2 2.3 GXR2 1.5 GXR2 1.8 GXR2 3.4 GXR2 (R) 2.1 GXR3 14.6 GXR3 16.3 GXR3 11.1 GXR3 (R) 6.6 GXR4 314.3 GXR4 304.6 GXR4 301.1 GXR4 306.3 GXR4 292.7 GXR4 (R) 310 GXR5 33.1 GXR5 33.9 GXR5 32.7 GXR5 33.4 GXR5 33.6 GXR5 (R) 31 GXR6 2.1 GXR6 1.5 GXR6 2.9 GXR6 1.7 GXR6 (R) 2.4 SGR1 29.7 SGR1 (R) 35.1 ASK2 54.3 ASK2 (R) 60 SDOl 135.3 SDOl 136.1 SDOl (R) 134 PACS 14.1 PACS 13.2 PACS 11.7 PACS (R) 12.3 136 Table A 1.8a) X R F instrument precision for major elements determined by analyzing the same standard sample throughout the analyses. Values are in weight percent of the oxide; b) RSD (%) for major elements determined by analyzing six sub-samples from a single homogenized sample (Drysdale, 1990; Feeney, 1995). a) Standard Fe Mn Ti Ca K Si A l Mg P Na JA2 4.34 0.08 0.4 4.51 1.54 25.73 8.24 4.6 0.06 2.71 JA2 4.34 0.08 0.4 4.51 1.51 25.68 8.36 4.51 0.07 2.64 JA2 4.34 0.08 0.4 4.45 1.56 25.8 7.68 4.63 0.07 2.72 JA2 4.41 0.08 0.41 4.53 1.47 26.63 8.24 4.64 0.08 2.43 Average 4.36 0.08 0.405 4.5 1.52 25.96 8.13 4.595 0.07 2.62 Standard 0.035 0 0.005 0.034 0.039 0.45 0.30 0.059 0.008 0.13 Deviation RSD% 0.80 0 1.24 0.77 2.58 1.738 3.76 1.29 11.7 5.14 A G V 4.85 0.08 0.64 3.54 2.51 27.48 9.49 0.93 0.21 2.88 A G V 4.83 0.08 0.64 3.52 2.47 27.51 9.44 0.98 0.21 3.14 A G V 4.85 0.08 0.64 3.5 2.49 27.56 8.86 0.92 0.2 2.97 A G V 5.04 0.08 0.68 3.69 2.52 29.96 9.81 1.03 0.25 3.55 Average 4.89 0.08 0.65 3.56 2.50 28.12 9.4 0.97 0.218 3.14 Standard 0.098 0 0.02 0.086 0.022 1.22 0.40 0.050 0.022 0.30 Deviation RSD (%) 2.0 0 3.1 2.4 0.89 4.3 4.2 5.2 10.2 9.5 b) Source Fe Mn Ti Ca K Si A l Mg P Na Drysdale 1.31 3.01 1.58 1.22 3.65 0.41 1.36 1.79 2.21 2.37 Feeney 1.57 0.43 0.36 0.88 0.38 0.42 1.17 3.12 5.71 137 Table A 1.9a) X R F instrument precision for minor elements determined by analyzing the same standard sample throughout the analyses. Values are in ppm. b) RSD (%) for minor elements determined by analyzing six sub-samples from a single homogenized sample (Drysdale, 1990; Feeney, 1995). a) Standard Zr Y Sr Rb Pb Zn Cu Ni Co Mn V Cr Ba Na A G V * 227 20 662 67 36 88 60 16 15 728 121 10 1226 4.26 A G V 240 18 646 69 34 84 60.2 8.8 12 799 144 17.2 1227 3.63 A G V 276 26 772 79 45 99.8 67.5 13.8 12 891 142 20.2 1308 3.79 A G V 245 20 633 64 40 89.4 63.7 10.4 15 769 133 17.5 1197 3.59 A G V 234 21 635 62 36 83.9 58.4 7.8 15 801 132 19 1240 3.66 A G V 240 25 634 63 36 84.5 66.9 13.1 16 782 132 19.1 1206 3.63 A G V 246 15 635 64 24 85.7 62.2 11.4 15 792 137 20 1238 3.59 A G V 232 24 640 63 23 85.3 64.1 10.8 15 789 147 15.6 1205 3.76 Average 245 21 656 66 34 88 63 11 14 803 138 18 1231 3.66 Standard 14.5 4.12 51.2 6.24 7.99 5.73 3.32 2.15 1.53 40.2 6.08 1.67 37.5. 0.08 Deviation RSD (%) 5.9 19 7.8 9.4 23 6.5 5.2 20 10 5.0 4.4 9.1 3.0 2.2 b) Source Zr Y Sr Rb Pb Zn Cu Ni Co Mn V Cr Ba Na Drysdale 1.30 4.85 1.00 3.75 10.7 4.25 5.20 9.85 12.2 0.95 2.25 6.65 1.35 0.35 Feeney 1.58 6.64 2.85 7.57 25.9 1.59 3.83 2.52 14.7 4.41 7.85 5.61 4.96 138 Table A L I O X R F instrumentprecision for I and Br determined by analyzing the standard sample throughout the analyses. Values are in ppm. Standard I Br IBR1 1035 1131 D3R1 1019 1119 IBR1 1031 1128 IBR1 1024 1112 IBR1 1022 1127 D3R1 1072 1121 Average 1034 1123 Standard Deviation 19.6 7.0 RSD (%) 1.89 0.62 IB R2 521 661 IBR2 511 630 IBR2 511 621 IBR2 514 609 D3R2 505 617 IBR2 523 720 Average 514 643 Standard Deviation 6.6 41.8 RSD (%) 1.29 6.50 IBR4 135 168 JJ3R4 124 157 IBR4 119 146 IBR4 120 143 IBR4 120 144 IBR4 133 167 Average 125 154 Standard Deviation 7.25 11.3 RSD (%) 5.80 7.33 139 Table A 1.11 X R F instrument precision for Mo determined by analyzing the same standard sample throughout the analyses. Values are in ppm. Standard Mo (ppm) GXR1 19.9 GXR1 19.4 GXR1 20.3 GXR1 21 GXR1 16.4 GXR1 16.5 Average 18.9 Standard Deviation 2.0 RSD (%) 10.5 I 140 For elements with analytical lines at longer wavelength than the Fe absorption edge (elements with atomic numbers < 27), the Compton peak is not proportional to mass absorption so matrix corrections on these elements were accomplished by taking a ratio of their peak amplitude to the intensity of an adjacent background wavelength. Corrections were also made for elements with analytical lines that overlapped those of another element: Ba and V on Cr; Rb on Y ; N i and Ti on V ; and Sr on Zr. Calcium was corrected for the addition of Ca by calcium carbonate by subtracting the weight percent of Ca as CaCC<3 from the weight percent of Ca determined by X R F . Major and minor element concentrations were corrected for bulk dilution by salt. Also concentrations of elements that are abundant in sea water were corrected for specific contributions from the seasalt present in each dried sediment sample. Most Mo values are below the detection limit of ~ 3 ppm (Francois, 1987) and most salt corrected Br values are near zero and not appropriate. Therefore, salt-corrected Br values are not listed. Major and minor element values are listed in Tables A4.3, A4.4, A4.6 and A4.7, Appendix 4. Al.4.1 Majors Preparation Glass discs were prepared for major element analysis based on a procedure outlined in Norrish and Hutton (1969). A sediment sample of 0.600 g was diluted with 3.600 g of Spectroflux 105 (47.03% L i 2 B 4 0 7 ; 36.63% L i C 0 3 ; 16.34% L a 2 0 3 ) . Samples from core SG55 from 9-12 cm, 14-20 cm, 35-65 cm were prepared with 0.400 g of sediment. Sample and flux were mixed in a platinum crucible and fused in a muffle furnace at 1100 °C for 30 minutes. Lanthanum oxide (La203) is used as a heavy absorber to increases the mass absorption of the sample which decreases differences in matrix effects between samples. The other two components in the flux reduce the melting temperature to ~ 700°C. After samples had cooled, Spectroflux 100 (L12B4O7) was added to the sample to make up for any weight loss during the fusion due to the presence of volatile components in the sample or flux such as water, CaCC»3 and organic matter. This is done to keep the sample to lanthanum ratio the same in samples as in standards used to calibrate the X R F instrument. The sample was remelted over a Meker burner in the fume hood and pressed into a disc using an aluminium mold and a brass plunger. The mold was preheated on the hot plate of the plunger at 400°C. The disc was left on the mold and covered with a glass bowl to cool in the fume hood. Glass discs were trimmed to fit sample holders of the X R F and stored in labelled plastic bags until analysis. 141 Al.4.2 Minors Preparation Pressed powder pellets were prepared for minor element analysis. Approximately 4.0 g of sample was compacted in a stainless steel die and covered with boric acid. For sample VG1 0-1 only one gram was used. The die was placed in a hydraulic press at 10 tons pressure for one minute. Pellets were labelled and placed in a box, with the boric acid side up to prevent contamination of the sediment from dust, until analysis by X R F . Several coarse-grained samples were mill ground so that compact, stable pellets could be formed. Samples that were mill ground include surface samples (0-1 cm) W6, W7, W8, K A 1 , K A 2 , and A12, the lowermost six samples from core A O and all samples from core A12. A1.5 Total Silver Silver was determined by isotope-dilution inductively-coupled plasma mass spectrometry (ID-ICP-MS) following microwave digestion of sediment samples in a strong acid cocktail. A V G Elemental Plasma Quad (VG Elemental, Surrey, UK) controlled by a Dell 486 computer with PQ Vision 4.1.1 software was used for the analyses. Instrument conditions are listed in Table A 1.12. The acid dilution isotope-digestion method was developed to determine low levels of Ag in marine sediments. Advantages of this technique are low detection limit, relatively simple sample preparation, greater precision and accuracy and no effect from variable sample recovery during preparation of the sample. Disadvantages of the method includes potentially isobaric interference from matrix elements, mass discrimination and memory effects during analysis and occasionally high blanks. The digestion procedures, isotope additions and instrumental technique used are described in detail in the following sections. Al.5.1 Digestion Method 1 Two digestion methods were used to prepare sample for ICP-MS analysis. The first method was used for samples with Ag concentrations less than about 100 ppb and the second method for samples with greater than 100 ppb of Ag. The second digestion method was preferred for several reasons: less sample and acids were used, time to prepare samples was reduced and potential exposure to air that may result in contamination was minimized. Although the second method offers several advantages, the detection limit for the sediment sample prepared by this method was higher (~ 85 ppb) than for the first method (~ 4 ppb and 142 Table A1.12 Instrument settings for Ag analysis by ICP-MS. Instrument Settings Value RF power (kW) 1350 Argon gas flow rate (1/min) Coolant flow rate 13.82 Auxiliary flow rate 0.699 Nebulizer flow rate 1.002 Operating pressure (mbar) Analyser 8.0 x 10"7 Intermediate 1.0 x 10- 4 Expansion 2.0 x 10° Ion lens setting Extraction 0.62 Collector 8.17 L I 8.1 L2 2.4 L3 4.7 L4 5.9 Pole bias 3.6 Resolution R 5.6 A M 3.4 Mass range 90-109 Detector mode Peak jumping Points per peak 1 Dwell time (ms) 10 Sample flow rate 0.6-0.7 ml/min Uptake time 85-90 seconds Total aquisition time 20 seconds 143 -31 ppb). The higher detection limit was due to the greater dilution of the sample (Table A1.13). Using the second digest for samples with < 100 ppb yielding blank signals as high as 10% of the analyte signal. Therefore, the first method was required to prepare samples with low Ag concentrations. Acids used in the digestions were of environmental grade quality and distilled and deionized water (DDW) was used. Each Teflon PFA digest vessel was first cleaned by adding ~ 10 ml of concentrated HNO3 and heating in a microwave. Vessels were sealed and placed in a C E M Digestion System 205 microwave oven at the following settings: 25 minutes/ 70% power/ 40 psi maximum pressure 60 minutes cool down Approximately, 250 mg of sample was accurately weighed in a plastic weighingdish and transferred to a clean lined teflon digestion vessel to which ~ 10 ml of concentrated . HNO3 acid was added. Approximately 0.5 g to 2.0 g of a working spike solution, enriched in 109Ag (99.7%),was accurately weighed and added to the digest vessel. Residue in the weighingdish was rinsed into the vessel to ensure that all of the spike was transferred. A predetermined weight of spike solution was added to each sediment sample so that the ratio of 109Ag to 107 Ag in the digest sample would be about 4 . Chiba et al. (1992) indicated that a ratio of 4 gave the best precision of Ag measured by ID-ICP-MS. A spike weight (k) was estimated by the following equation: k = CWsample S (6.674 * 10 1 0 ) where C is the estimated concentration, in ppb, of Ag in the sediment sample, S is the concentration of the working spike in moles/g and W s a mple the sample weight. Next, 4 ml of concentrated HC1 and 4 ml of concentrated HF were added to the vessel. Vessels were sealed and samples digested in the microwave at the following settings: 70 minutes/ 50% power/ 50 psi maximum pressure 60 minutes cool down Each run comprised 12 vessels, of which two to three were blanks and one was a reference standard. Liners were removed from the vessels and placed under heat lamps for ,144 Table A1.13 Detection limit of redigest solutions analyzed by ICP-MS for the column and on-line methods using digest methods 1 (250 mg) and 2 (10 mg). Procedure 3s (counts/s) D . L i n sample solution (ppb) Sample wt (g) Solution wt (g) Dilution factor D.L. in sediment (ppb) Column 5670 0.66 0.250 1 4 2.6 On-line (250 mg) 4251 0.52 0.250 15 60 4-31.2 On-line (10 mg) 4778 0.57 0.010 1.5 150 85.5 145 about 12 hours until the samples evaporated to dryness. This step removes residual HF, which etches quartz components of the ICP-MS. Liners were placed back into the digestion vessels and -15 ml of 0.5N HC1 added. Vessels were closed and samples redigested at the following settings: 30 minutes/ 65% power/ 40 psi maximum pressure 60 minutes cool down After cooling, the redigest samples were transferred to clean, labelled 15 ml HDPE (high density polyethylene) bottles and stored until analysis. Al.5.2 Digestion Method 2 In this method, sediment samples were digested in 6 ml Teflon PFA vials that were placed in the larger digestion vessels. The small vials were cleaned by adding ~ 1.5 ml of concentrated HC1 to each, placing two sealed vials into one digestion vessel that contained a teflon lid and 6 ml of water, and running through the following microwave program: 20 minutes/ 60% power/ 40 psi maximum pressure 30 minutes cool down Water was placed at the bottom of the large digest vessel to reduce the amount of energy reflected back to the magnetron (reflected energy can cause the magnetron to overheat which reduces its working life), and to increase the pressure and temperature outside the vial. This permits higher pressures to develop inside the vials (Kojima et al., 1992) which increases the efficiency of the digestion. Water also absorbs acid fumes that may have escaped from the vials. Vials were opened in a fumehood and rinsed with DDW. Next ~ 10 mg of sample were accurately weighed into a clean vial and ~ 50-300 mg of a ^ A g working spike were added. Sediment weights were kept above 5 mg and below 20 mg. For samples with low Ag concentrations (~ 100-200 ppb), higher sample weights were preferred. The spike weight was kept below 300 mg so that the volume in the vial was less than -1 .5 ml. At greater volumes, sample can be lost from vials during the digestion. 146 In a fumehood, ~ 0.4 ml each of concentrated HNO3, HC1 and HF were added to each vial. Typically for a set of 24 vials, 18 samples, four blanks and two standards were prepared, and digested using the following program: 30 minutes/ 60% power/ 50 psi maximum pressure 30 minutes cool down Vials were removed from the vessels and placed under heat lamps until the sample evaporated to dryness, about 5-7 hours. Then, ~ 1.5 ml of 0.5N HC1 was added to each vial and samples redigested in the microwave at the following settings: 20 minutes/ 60% power/ 40 psi maximum pressure 30 minutes cool down Samples were transferred to acid cleaned, labelled 1.5 ml conical polypropylene micro centrifuge tubes and stored until analysis. Al.5.3 ICP-MS Analysis Potentially interfering elements were removed from the sample matrix using an anion exchange resin, either using a column for each sample or an "on-line" method in which the resin is placed upstream from the plasma cell of the ICP-MS. A l l silver values presented in this paper were determined with the on-line method except for surface samples K A 2 , W7, W8, SG32, SG52, and core samples SG17, SG29 and SG42 for which the column procedure and direct analysis were used. A styrene-type quaternary ammonia resin (Dowex 1-X8,100-200 mesh, chloride) was used in both procedures. With this resin, Ag is effectively separated from interfering elements because of the interaction of the elements with the resin in various acid solutions. Silver adsorbs to the resin in dilute HC1 but not in any concentration of HNO3. Silver is weakly adsorbed to the resin in concentrated HC1. Niobium is only slightly adsorbed to the resin in HNO3 and dilute HC1. Zirconium is only slightly adsorbed to the resin in HNO3 and not adsorbed in dilute HC1. Consequently Ag in a 0.5 N HC1 solution adheres to the resin while Zr and Nb pass through. The sorbed Ag is eluted with HNO3. Analysis time with the on-line column procedure was about 9-10 minutes per sample. Standard reference materials were used to verify the accuracy of the procedure. 147 Measured and recommended values for marine sediment reference material MESS-2 and BCSS-1 and geological rock standards are presented in Table A 1.14. Relative standard deviations were determined for standards using six or more sub-samples and ranged from 8-18% (Is). Several tests were done throughout the early stages of the project to determine contamination sources and several steps were taken to reduce potential contamination. Overall analytical precision was determined by analyzing six sub-samples of SG55 8-9 cm on different days in different runs. The relative standard deviation was 0.8% for samples prepared in new vials and 7% for sample prepared in used vials. Both sample sets were prepared using digest method 2 and analyzed by on-line ICP-MS analysis. Despite cleaning, residual material may have been present in the used vials which resulted in the higher RSD for that sample set. A 1.5.4 Calculations Stable isotopes of Ag occur in almost equal abundance 10 7 Ag (51.839%) and 109Ag (48.161%). The ratio of the measured isotope signal was used to determine the concentration in ppb of Ag in the sample using the isotope dilution equation: C = S X Wspike * ^Ailspike * Agatomic weight * (Rsample z£spike ) * l x l O 9 107 Agnatuj-al WSample (Rnatural~ Rsample) where C = concentration of Ag (ppb) S = moles/g of Ag in the (working) spike solution Wspike = weight of spike added to the sample (g) 1 0 7 Ag S pi ] i e = abundance o f 1 0 7 A g in the spike = 0.3% 107Agnaturai = natural abundance o f 1 0 7 A g = 51.839% Agatomic weight = 107.8682 g/mole WSampie = weight of sediment sample (g) Rsample = the ratio o f 1 0 9 A g blank-corrected count rate to 1 0 7 Ag blank-corrected count rate in the sample Rspike = the ratio of 1 0 9 A g to 1 0 7 A g abundance in the spike = 99.7%/ 0.3% = 332.3333 Rnatural = natural ratio of 1 0 9 A g to 1 0 7 A g = 48.161%/ 51.839% = 0.92905 148 Table A1.14 Accuracy of the on-line ICP-MS procedure for standard samples digested by method 1 and method 2. Values are compared to the recommended value. Both marine sediment standards and geological standards were used. Each number represents a different sample. Values are in ppb. Reference Description Recommended Method 1 Method 2 Material Ag value (ppb) Digest (ppb) Digest (ppb) MESS-2 Marine 180+/- 20 181 186 sediment- 176 Beaufort Sea 171 BCSS-1 Marine 110+/- 30 111 104 sediment-Gulf 111 119 of St. Lawrence 138 Average 120 113 118 169 116 RSD 131 122 7.8 % 111 120 Sco-1 Analyzed Cody 134 129 138 Shale 145 132 129 139 186 133 137 Average 137 151 133 RSD 211 12.2% 136 181 145 157 169 RGM-1 Glass Mountain 108 96 122 Rhyolite 97 99 100 Average 97 115 125 RSD 125 18.2 % 156 STM-1 Analyzed 79 75 65 Nepheline 81 Syenite 98 QLO-1 Quartz Latite 64 56 63 56 129 149 Count rates of 107 and 109 of the sample were blank corrected by subtracting an average of the count rates for the full procedure blanks. Mass 109 to 107 count rates in samples were corrected for mass bias by multiplying the ratio by the mass bias correction factor: maSS bias = Rnatural -^measured where Rmeasured is the average ratio of 109Ag to 107Ag measured by ICP-MS in a 10 ppb spectrometric standard solution of Ag by ICP-MS. There is evidence that the mass bias correction factor can change throughout a the ICP-MS analysis and that changes are significant enough to change the concentrations of Ag calculated. For example, the concentration of Ag in six SG55 8-9 cm sub-samples were calculated using a mass bias determined at the beginning of a run and at the end. The actual samples were analyzed at the end of the analysis. Concentrations determined using the mass bias at the end of the run are ~ 17% lower than those calculated using the mass bias at the start of the run. The former concentrations using the mass bias determined at the end (the time the samples were run) is more similar to an average value determined for a different six sub-samples for SG55 8-9 determined using new vials. Values are listed in Tables A1.15a and A1.15b. Clearly, these results show that the mass bias can significantly change the calculated Ag concentration of a sample. Therefore, it is recommended that the mass bias be monitored throughout the ICP-MS analysis. Silver concentrations are presented on a salt free basis. Salt-corrected values for surface samples and cores are listed in Tables A4.1 and A4.5, Appendix 4. A few samples were taken from approximately the same location at different times during this study. These results are presented in Table A4.9. Surface sediment samples from other locations in British Columbia were analyzed and are presented in Table A4.10. These values are not salt corrected. 150 Table A l . 15a) Analytical precision of the on-line ICP-MS procedure using digest method 2 with new and used vials. Two different values were determined for each of the samples digested in the used vials. The first value was determined using a mass bias from the start of the analysis and a second using a mass bias determined at the end of the analysis; b) mass bias values determined at the start and end of the analysis. a) Sample Method 2 digest- Method 2 digest - used vials new vials Mass bias calculated Mass bias calculated at start (0.9867) at end (1.1161) SG55 8-9 118 132 112 Ag (ppb) 119 142 120 117 134 115 120 132 114 119 123 106 119 150 128 Average (ppb) 119 136 115 Standard deviation 1 9 7 (ppb) RSD (%) 0.87 6.9 6.5 b) Sample 107Ag 109Ag 109/107 Mass bias 10 ppb Ag Start 74156 69651 0.9392497 75364 71434 0.9481185 74365 69898 0.9374103 Average 0.9415928 0.9867 10 ppb Ag End 20161 16687 0.8276871 20118 16842 0.8371608 Average 0.8324239 1.1161 151 A 1.6 Role of Particle Size Eleven dried and unground samples were separated by sieving into three grain size fractions > 125 pirn, 63-125 p:m (fine sand) and < 63 pirn (mud) and each fraction was analyzed for silver. Samples that covered a range of coarse to fine material were chosen. Sample sizes ranged from ~ 3.5 g to 20 g. Samples were disaggregated with a clean paint brush in the 125 pm sieve and gently agitated. The same procedure was used for the underlying 63 p:m sieve. The retained fractions were weighed and the percentage of each grain size fraction determined in each sample. Grain size fractions were placed in plastic vials until digestion and analysis. Results are listed in Table A4.11. Values are not salt corrected. Stainless-steel sieves were used throughout this exercise; their was no evidence that the sieves contaminated the size fractions with silver. Other samples were also separated into the grain size fractions mentioned above but were not analyzed for silver. The percentage of the > 125 pm, 63-125 pm and < 63 p:m are listed in Table A4.11 in Appendix 4. A 1.7 Lead An aliquot of a sample or blank prepared for silver analysis was diluted with 2N HNO3 and analyzed for Pb by ICP-MS. A 1 ml aliquot was used for samples digested in the large containers and 0.2 ml was used for samples digested in the small containers. An aliquot of 100 ppb indium (In), either 1 ml or 0.2 ml, was added and the solution diluted about tenfold with 2N HNO3. Indium was used as an internal standard to correct for changes in the sensitivity of the ICP-MS during analysis (Taylor and Garbarino, 1991). Instrument settings are listed in Table A1.16. Standard solutions of approximately 2.5 ppb, 5 ppb, 10 ppb, 15 ppb and 20 ppb were prepared by diluting a spectrometric standard solution of 1000 ug/ml of Pb with 2N HNO3, and spiking with 100 ppb indium to bring the In level to ~ 10 ppb, the same as in the samples and blanks. A l l solutions were accurately weighed. Lead concentrations in samples and blanks were determined using a linear calibration curve of blank-corrected lead 208 count rates versus the concentration of Pb in the standards. Lead 208 count rates were used because this is the most abundant naturally-occuring isotope of Pb and the counts were highest. Changes in the sensitivity of the ICP-MS were obviated by normalizing the Pb 208 count rates (cr) to In count rates as follows: 152 Table A 1.16 Instrument settings for Pb analysis by ICP-MS. Instrument Settings Value RF power (kW) 1350 Argon gas flow rate (1/min) Coolant flow rate Auxiliary flow rate Nebulizer flow rate 13.82 0.699 1.002 Operating pressure (mbar) Analyser Intermediate Expansion 8.0 x 10- 7 1.0 x 10"4 2.0 x 10 0 Ion lens setting Extraction Collector L I L2 L3 L4 Pole bias 0.62 8.17 8.1 2.4 4.7 5.9 3.6 Resolution R A M 5.6 3.4 Mass range 115-208 Detector mode Peak jumping Points per peak 1 Dwell time (ms) 10 Uptake time 15-20 seconds Total aquisition time 20 seconds 153 2 0 8 P b cr corr in = 2 0 8 P b cr * 1 1 5 In cr in the first sample analyzed 1 1 5 In c r c o r r i n the sample, blank or standard Variability in In count rates caused by varying In concentrations in the solutions were corrected for as follows: us i n crCOrr = 1 1 5 I n c r * In cone, of the first sample analyzed In cone, of the sample, blank or standard Corrected counts for the standards were then blank-corrected by subtracting the average of three 208pb corrected counts of a 2N HNO3 solution spiked with In. Lead concentrations in the samples were determined using the calibration curve and then that concentration, in ppb, used to determine the concentration of lead in the sediment sample in ppm as follows: Pb sediment (ppm) = Pb s a m p le (ppb) * DF * Weight A g sample digest Ig) Weight sediment sample (g) where DF is the dilution factor of the Ag sample-digest aliquot. Finally, Pb concentrations of the samples were blank corrected by subtracting the average Pb concentration of the blanks from the sample Pb concentration. Marine sediment samples and geological standards were analyzed to determine the accuracy of the procedure for 1 ml (digest method 1) and 0.2 ml aliquots (digest method 2). The results are listed in Table A1.17. Standard values are generally lower for samples prepared with the small vessels since some solution was lost from the container during digestion. The detection limit is 1.0 ppb (1.0 ppm in the sample). Six sub-samples of a single sample were analyzed for both procedures and yielded an RSD of 3.3% for digest method 1 and 5.6% for digestion method 2 (Table A1.18). Lead was also determined by X R F ; however the RSD using that approach is much greater than the ICP-MS method so the Pb values determined by ICP-MS were used in this study. Concentrations were corrected for dilution by seasalt and are presented in Table A4.1 and A4.5, Appendix 4. 154 Table A l . 17 Accuracy of the ICP-MS analysis of Pb using digest methods 1 and 2. Values of the marine sediment standards and geological standards are compared to the recommended value. Each number represents a different sample. Values are in ppm. Reference Recommend Digest Digest Material ed value method 1 method 2 (ppm) MESS-2 21.9 +/- 3.4 21.2 22.8 20.9 20.8 21.3 18.0 BCSS-1 22.7 +/- 3.4 21.4 21.2 21.4 21.2 25.8 18.9 21.5 18.2 21.4 16.6 20.1 19.7 18.8 18.6 16.9 ScO-1 31 42.1 32.9 41.0 27.4 18.4 27.2 25.5 24.1 22.3 22.0 RGM-1 24 27.8 17.3 31.4 20.4 21.2 21.5 29.7 21.8 STM-1 17.7 17.2 21.3 24.9 QLO-1 20.4 25.0 18.2 BCR-1 13.6 14.2 10.6 9.1 9.9 10.4 9.9 12.2 14.5 155 Table A 1.18 Analytical precision for Pb analysis. Digest in large Digest in small containers-same day vials-same day (n=6) (n=6) SG55 8-9 cm 22.78 18.58 21.93 18.95 21.55 17.57 20.63 19.06 21.33 20.03 21.46 17.17 Average (ppm) 21.61 18.56 Standard Dev (ppm) 0.71 1.05 RSD (%) 3.30 5.64 156 A 1.8 Seasalt Corrections Al.8.1 Chlorinity Chlorinity was determined titrimetrically by a method outlined in Drysdale (1990). Approximately 100 mg of sediment was weighed directly into a plastic centrifuge tube, 5 ml of distilled water were added and the tube was held on a vortex stirrer for about 1 minute to dissolve the salts. Samples were centrifuged using a Sorvall T600B Centrifuge for 10 minutes at 3, 000 rpm. One ml of supernatant was transferred to a 10 ml glass beaker containing a magnetic stir bar, 2 ml of distilled water and 100 ul of K2Cr04. The glass beaker was set on a Corning PC-353 stirrer and the mixture titrated with AgN03 dispensed from a Gilmont microburette until the end point, which was indicated by a color change from yellow to red. A red precipitate of Ag2Cr04 forms once all the halides in the sample have been precipitated with Ag (Millero and Sohn, 1982). The volume of AgN03 required was recorded. Three mixtures were prepared and titrated for each sample and an average volume of A g N 0 3 used to calculate the percent chloride in the sample. A solution of NaCl with a known amount of CI was used to standardize the AgN03. Approximately 100 ul NaCl (0.086061 M) was added to each of five 10 ml glass beakers which contained a magnetic stir bar, 2 ml of distilled water, and 100 ul of indicator solution. These mixtures were titrated and an average value of the A g N 0 3 volume required was used to calculate the concentration of the A g N 0 3 as follows: A g N 0 3 molarity ~ NaClypiume * NaClm oi a rity AgN0 3 v o lume where volume and molarity units are ml and mole/1, respectively. It is important that air bubbles are cleared from the microburette as otherwise the volume of A g N 0 3 added will be incorrect. After each analysis the tip of the microburette was rinsed with distilled water and a small amount dispensed to prevent contamination of the next sample. The burette was completely refilled with AgN03 before the next titration. The chloride content in a given sediment sample was calculated as: %C1 = A g N Q 3 v o i * AgNQ 3 m o i a r i tv * ml of water * Gnomic weight * 100 samplevoiume * sampleweight * 1000 157 %C1 = A g N O w * A g N O ^ ^ ^ i ^ * 5ml * 35.45g/mole * 100 lml * sampleweight * 1000ml/l where volume and molarity units are ml and mole/1. Al.8.2 Salt Correction Weight percent chloride was determined to correct the sediment concentrations of some elements (Na, Mg, Ca, K , Br, S, and Sr) for the contribution of these ions from seawater. Elemental concentrations, as weight percent or ppm, were corrected using the following general formula: Element correct = Element m e a s u r e d - [(FJemeni s^ j a^)*(%Clme a Sured)] CI seawater where Elementseawater is the element concentration in seawater and Cl" s e awater the chlorine content in seawater. Specific formulas are: %NaC Orrect=Nam e a s u r ed - (0.556 * %C1) %MgCorTect=Mgmeasured " (0.067 * %C1) %Ca c o rrecFCam easured - (0.021 * %C1) %Kcorrect=KmeaSured - (0.02 * %C1) %Scorrect=Smeasured - (0.04679 * %C1) p p m B r c o r r e c t = B r m e a s u r e d - (34.8 * %C1) ppmSr c o r r e c t = S r m e a s u r e d - (4.13 * %C1) Finally, all elements were corrected for dilution by bulk seasalt using: Elementgait f r e e = Elementmeasured or correct * 100 [100-1.82 (%C1)] A l l major and minor element data are presented on a salt-free basis and are listed in Append 4. Chloride values are listed in Tables A4.1 and A4.5, Appendix 4. 158 A 1.9 Carbon and Nitrogen Isotopes Carbon and nitrogen isotopes were analyzed separately by gas chromatrography-mass spectrometry using a VG-Isotech Prism mass spectrometer in both cases and a Carlo-Erba 1106 C H N elemental analyzer for carbon isotope ratios and a Fisons NA-1500 CNS analyzer for nitrogen isotope ratios. Approximately 35 ug of nitrogen was required for S ^ N analysis. Approximately 10-40 mg and 50-250 mg of sediment were used for fine-grained and coarse-grained samples, respectively. Samples were weighed into tared tin cups on a Mettler M3 balance, and the cups folded closed and placed in a plastic holder until analysis. Samples prepared for S^Coj-g anayses were treated with 10% H C l to remove inorganic carbon. About 200 mg of sediment were placed in a 20 ml glass scintillation vial and ~ 5 ml of 10% H C l acid was added. The vials were kept in an oven at ~ 50°C for ~ 2 days until the samples were dry. Then about 5-15 mg (fine-grained) and 20-50 mg (coarse-grained) were weighed into tin cups. About 100 ug of organic carbon was required for each analysis. Tin cups were closed and samples stored in a plastic holder until analysis. Gases produced by flash combustion in the elemental analyzer were transported by a helium stream through copper wire at 650 °C to reduce N O x to N2 and through magnesium perchlorate to remove water. An additional trap to remove CO2 was used during the nitrogen isotope analyses. The gases were separated by a chromatographic column at 50 °C, and introduced to the mass spectrometer as "pure" CO2 and N2. The abundance of carbon isotopes and were determined from the mass ratios 45/44 and 46/44, relative abundances of the nitrogen isotopes 1 4 N and 1 5 N were determined from the ion peaks of N2+ at mass numbers 28 ( l 4 N l 4 N ) , 29 ( 1 4 N 1 5 N ) and 30 ( ^ N ^ N ) . Values are reported as delta values in units of parts per thousand (%o) and calculated with the following formula: d value= (R^amriezEstandard) X 1000 s^tandard The standard for nitrogen is air and for carbon is PDB (Peedee Belemnite). Reference materials and blanks were run periodically to calibrate the system. Samples analyzed for 5 1 5 N before September 1,1995 were corrected for a change in the 8 ^ N value of the reference material NBS-1 and NBS-2 by subtracting 0.8%o so that values determined after September 1,1995 could be compared. Six sub-samples of a single sample were prepared and 159 analyzed to determine the precision of the procedure. This was done twice for both analyses and results are listed in Table A1.19. Precision estimates for 8 ^ N ranged from ± 0.15%o (Is) for 5903-22 to ± 0.4%o (Is) for SG29 0-1 cm. For 8 1 3 C o r g the respective estimates were ± 0.14%o (Is) and ± 0.03%o (Is). A l l 8 1 5 N and 8 1 3 C o r g are listed in Tables A4.1 and A4.5, Appendix 4. ALIO Pb-210 Samples from cores SG55, AO, SG17, SG29 and SG42 were analyzed for 2 1 0 P b by Flett Research Ltd. (Winnipeg, Manitoba) by a procedure outlined in Eakins and Morrison (1978). 210pb has a have life of 22.26 years and is useful for estimating dates and accumulation rates over the last 100 years. 2 1 0 p b is a radionuclide formed in the decay series of uranium-238. Samples were analyzed for 210pD D y measuring the activity of the alpha emitting daughter, 210p o > based on the assumption that the daughter is in secular equilibrium with 210pD j n other words, the rate of supply of 210p o f r o m the decay of 210pb j s equal to the rate of loss of 2 1 0 P o from its decay to 2 0 6 P b (Libes, 1992). The half-life of 2 1 0 P o is 138.4 days. The uncertainty in the 210po counts is approximatey ~ 4% for SG55, ~ 20% for A O and ~ 7% for SG17, 29, and 42. A sedimentation rate was determined only for core SG55. Values of 210po from cores AO, SG17, SG29 and SG42 were too low to obtain a useful sedimentation rate. Excess 2 1 0 P b was determined in core SG55 by subtracting a value from the bottom of the core from the sediment samples and correcting that value for dilution by seawater. Depth was converted to total cumulated mass to correct for compaction using porosity. Porosity (0) was determined from percent chloride through the following equations: 0 = V w a t e r / ( V w a t e r + V s olids) 0 = W w a t e r / (WWater + Wj0lids) Dwater Dwater Dsolids where V is the volume, W the weight, and D the density. The density of water and solids is taken as 1.02 g/cm 3 and 2.6 g/cm 3, respectively. Weight of the water for a one gram sediment sample was determined by: WWater =%£lx 1QQ0 X 1.80655%O X W s e d i m e n t 100 S 160 Table A 1.19 Analytical precision estimate for and 8 l 3 Corg analysis determined by analyzing six sub-samples of a given sample. Sample 8 1 3 C (%o) 8 ! 5 N (%O) SG29 4-5 cm -23.18 2.53 -23.5 2.65 -23.14 3.53 -23.33 2.39 -23.37 2.91 -23.42 2.84 Average -23.32 2.81 Standard Deviation 0.14 0.40 5903-22 -23.182 6.471 -23.17 6.392 -23.204 6.582 -23.198 6.639 -23.262 6.816 .' -23.198 6.683 Average -23.202 6.597 Standard Deviation 0.032 0.152 161 where %C1 is weight percent of chloride determined by titration with AgNC«3. Salinity (S) is 31.17 and W is the weight in grams. Then the cumulated mass (z) in g/cm^ determined by: n z = I [ D s o l i d s (l-0i)zi] i=l where D is density, 0i porosity of the sediment interval and zj the depth interval. The In (excess 210pb) w a s plotted versus the cumulation for each sample and a linear equation taken for samples below the mixed layer. Assuming that the flux of 210pb a n d the sedimentation rate were constant a mass accumulation rate (s) in g/cm^/yr was determined from the slope of the linear equation: ln(excess2 1 0Pb) = In A - In A° = -lz s where the slope is -1/s and 1 is the 210pb decay constant (0.0311/yr). Sedimentation rate (s') in cm/yr was determined from the following equation: S' = s/(Dsolids(l-0o)) where 00 is the porosity at the sediment/water interface (~ 0.86) and D s o l i d s is the density of the solids (2.6 g/cm 3). A sedimentation rate in g/cm2yr and cm/yr was determined from the bottom three points in the core to be ~ 0.26 g/cm2yr and 0.72 cm/yr. Values for 210p o a r e listed in Tables A1.20 and A 1.21. 162 Table A1.20 Data for 2 1 0 P b analysis of cores AO, SG17, SG29, and SG42. Sample Depth Interval (cm) ^ 0 p 0 (dpm/g) A O 0-1 1.54 1-2 1.43 2-3 1.06 3-4 0.92 4-5 0.86 6-7 0.65 9-10 0.97 14-16 0.84 22-24 0.30 30-32 0.57 SG17 0-1 4.03 1-2 3.60 2-3 4.00 3-4 3.78 4-5 3.94 5-6 3.36 6-7 3.53 SG29 0-1 3.95 1-2 3.94 2-3 4.07 3-4 4.61 4-5 4.45 5-6 4.26 6-7 3.82 SG42 0-1 5.87 1-2 5.14 2-3 5.62 3-4 5.11 4-5 5.69 5-6 5.71 6-7 5.18 163 Table A1.21 Data for 2 1 0 p b analysis of core SG55. Sample Depth Interval (cm) Cumulative mass (g/cm2) 210p 0 (dpm/g) Excess 2 10p D (dpm/g) (salt correct) SG55 1-2 0.76 12.89 11.52 2-3 1.15 12.41 10.96 3-4 1.54 12.88 11.46 4-5 1.97 11.95 10.39 5-6 2.39 10.85 9.22 7-8 3.23 10.67 9.04 9-10 4.11 9.77 8.01 16-18 7.72 5.87 3.87 26-28 12.17 5.08 3.03 60-65 - 2.24 -164 Appendix 2: Sample Locations 165 Table A2.1 Location and water depth of cores and grab samples (gs) collected from the Strait of Georgia. Date of collection and core length are indicated. Water depths for cores SGI, SG2, SG56, AG51, and AG59 were determined from a bathymetry map of the Strait of Georgia (L/C-3463), Canadian Hydrographic Service. Core Date Latitude (N) Longitude (W) Water Depth (m) Core length (cm) VG1 24-Aug-94 49 12.120 123 20.092 176 50 VG2 24-Aug-94 49 11.902 123 22.313 238 40 VG3 24-Aug-94 49 10.423 123 22.214 230 35 VG4 24-Aug-94 49 11.82 123 28.36 327 40 VG5 24-Aug-94 49 14.57 123 33.66 359 32 SGI 23-May-95 49 1.90 123 26.40 321 7 SG2 23-May-95 49 7.11 123 29.99 355 50 SG3 23-May-95 49 11.0 123 31.99 352 7 SG4 24-May-95 49 12.934 123 32.144 352 45 SG5 24-May-95 49 15.49 123 32.52 253 7 SG6 24-May-95 49 14.996 123 26.04 253 7 SG7 24-May-95 49 12.498 123 25.995 300 7 SG8 24-May-95 49 10.4 123 25.984 250 7 SG9 24-May-95 49 10.457 123 20.257 170 7 SG10 24-May-95 49 10.435 123 19.039 130 7 SG11 24-May-95 49 10.357 123 18.539 110 7 SG12 24-May-95 49 10.450 123 18.191 90 7 SG13 24-May-95 49 10.484 123 17.816 71 7 SG14 24-May-95 49 10.532 123 17.779 50 7 SG15 24-May-95 49 11.960 123 17.810 52 7 SG16 24-May-95 49 11.937 123 18.019 72 7 SG17 24-May-95 49 11.901 123 18.159 90 7 SG18 24-May-95 49 11.930 123 18.581 110 7 SG19 24-May-95 49 11.890 123 18.938 131 7 SG20 24-May-95 49 11.869 123 20.023 170 7 SG21 24-May-95 49 12.53 123 19.79 160 7 SG22 24-May-95 49 12.56 123 18.70 130 7 SG23 24-May-95 49 12.55 123 18.30 108 7 SG24 24-May-95 49 12.55 123 18.07 90 7 SG25 24-May-95 49 12.55 123 17.89 70 7 SG26 24-May-95 49 12.56 123 17.75 50 7 SG27 24-May-95 49 13.04 123 17.65 50 7 SG28 24-May-95 49 13.01 123 17.76 70 7 SG29 24-May-95 49 13.015 123 17.95 91 7 SG30 24-May-95 49 12.996 123 18.188 109 7 SG31 24-May-95 49 12.988 123 18.644 131 7 SG32 24-May-95 49 12.997 123 19.503 170 7 SG39 24-May-95 49 13.989 123 17.469 50 7 SG40 24-May-95 49 14.000 123 17.594 69.5 7 SG41 24-May-95 49 13.991 123 17.776 90 7 SG42 24-May-95 49 14.000 123 18.023 111 7 166 Core Date Latitude (N) Longitude (W) Water Depth (m) Core Length (cm) SG43 24-May-95 49 13.980 123 18.300 130 7 SG44 24-May-95 49 13.995 123 19.145 170 7 SG45 24-May-95 49 15.011 123 19.210 170 7 SG46 24-May-95 49 15.019 123 18.499 130 7 SG47 24-May-95 49 14.975 123 18.120 110 7 SG48 24-May-95 49 15.004 123 17.855 90 7 SG49 24-May-95 49 15.048 123 17.632 71 7 SG50 24-May-95 49 15.062 123 17.406 50 7 SG51 24-May-95 49 18.004 123 20.814 166 35 SG52 24-May-95 49 17.52 123 23.510 258 45 SG53 24-May-95 49 16.938 123 26.191 151 40 SG54 25-May-95 49 19.222 123 49.989 415 7 SG55 25-May-95 49 17.060 123 49.952 414 65 SG56 25-May-95 49 14.789 123 50.112 263 7 SG57 25-May-95 . 49 17.00 123 39.93 275 7 SG58 25-May-95 49 15.06 123 39.97 388 10 SG59 25-May-95 49 12.50 123 40.06 373 7 AG1 30-Jul-96 49 09.5 123 20.29 171 2 AG2 30-M-96 49 09.48 123 19.36 130 2 AG3 30-Jul-96 49 09.5 123 18.83 114 2 AG4 30-Jul-96 49 09.5 123 18.26 92 2 AG5 30-Jul-96 49 09.51 123 17.84 72 2 AG6 30-Jul-96 49 09.49 123 17.6 50 2 AG7 30-Jul-96 49 09.47 123 17.46 31 2 AG8 30-M-96 49 10.5 123 17.58 31 2 AG9 30-Jul-96 49 11.95 123 17.61 32 2 AGlOgs 30-Jul-96 49 12.61 123 17.6 41 2 AG11 30-M-96 49 12.57 123 17.57 30 2 A G l l g s 30-Jul-96 49 12.57 123 17.57 30 2 AG12gs 30-Jul-96 49 12.52 123 17.53 20 2 AG13 30-Jul-96 49 13.12 123 17.46 20 2 AG13gs 30-M-96 49 13.12 123 17.46 20 2 AG14 30-Jul-96 49 13.03 123 17.49 29 2 AG15 30-Jul-96 49 13.02 123 17.54 41 2 AG16 30-M-96 49 13.06 123 17.59 50 2 AG17 30-M-96 49 13.07 123 17.9 89 31 AG18 30-Jul-96 49 14.01 123 17.39 50 1 A G 19 30-Jul-96 49 14.03 123 17.328 40 1 AG20 30-Jul-96 49 14.002 123 17.282 31 1 AG21 30-Jul-96 49 14.024 123 17.233 20 1 AG22 30-Jul-96 49 15.1 123 17.153 20 1 AG23 30-Jul-96 49 15.07 123 17.2 30 1 AG24 30-M-96 49 15.018 123 17.284 40 1 AG25 30-Jul-96 49 15.048 123 17.39 51 1 167 Core Date Latitude (N) Longitude Water Depth Core Length (W) (m) (cm) AG26 30-Jul-96 49 15.505 123 17.12 21 1 AG27 30-Jul-96 49 15.514 123 17.18 30 1 AG28 30-Jul-96 49 15.499 123 17.263 40 1 AG29 30-Jul-96 49 15.50 123 17.40 50 1 AG30 30-Jul-96 49 15.532 123 17.584 66 1 AG31 30-Jul-96 49 15.533 123 17.923 85 1 AG32 30-Jul-96 49 15.503 123 18.317 110 1 AG33 30-Jul-96 49 15.507 123 18.802 133 1 AG34 30-M-96 49 15.47 123 19.4 171 1 AG35 30-M-96 49 15.482 123 19.843 197 1 AG36 30-M-96 49 16.544 123 20.636 200 1 AG37 30-M-96 49 16.527 123 20.036 167 1 AG38 30-M-96 49 16.493 123 19.399 130 1 AG39 30-M-96 49 16.534 123 18.897 107 1 AG40 30-Jul-96 49 16.531 123 18.323 87 1 AG41 30-M-96 49 16.487 123 17.963 69 1 AG42 30-M-96 49 16.498 123 17.572 47.8 1 AG43 30-M-96 49 16.505 123 17.392 40 1 AG44 30-M-96 49 16.470 123 17.204 30 1 AG45 30-Jul-96 49 16.537 123 17.069 18 1 AG46 30-Jul-96 49 18.064 123 17.360 120 1 AG47 30-Jul-96 49 18.0 123 19.36 154 1 AG48 30-Jul-96 49 18.0 123 22.11 242 1 AG49 30-Jul-96 49 17.99 123 24.25 247 1 AG50 30-Jul-96 49 18.0 123 26.46 160 1 AG51 30-Jul-96 49 18.98 123 26.54 20 1 AG52 30-Jul-96 49 19.01 123 24.35 176 1 AG53 30-Jul-96 49 19.0 123 22.1 248 1 AG54 30-Jul-96 49 19.0 123 19.66 154 67 AG55 30-Jul-96 49 19.13 123 17.66 130 1 AG56 30-Jul-96 49 19 123 15.05 91 1 AG57 30-Jul-96 49 18.02 123 15.05 73 1 AG58 31-M-96 49 18.0 123 12.6 33 1 AG59 31-M-96 49 19.035 123 12.606 40 1 168 Table A2.2 Location of cores collected from Sturgeon Bank and Roberts Bank. Date of collection and core length are indicated. Cores were sampled at low tide when the surface was exposed to the atmosphere. Core Date Latitude (N) Longitude (W) Core Length (cm) AO 12-M-95 49 12.899 123 12.488 32 K A 1 12-M-95 49 12.251 123 13.728 2 K A 2 12-M-95 49 11.892 123 13.927 2 A12 12-M-95 49 9.14 123 12.598 24 W6 12-M-95 49 12.48 123 13.66 2 W7 12-M-95 49 11.57 123 14.34 2 W8 12-Jul-95 49 10.189 123 14.399 2 BPt-1 2-Jul-96 49 3.0 123 8.5 36 A10 2-Jul-96 49 11.501 123 13.292 31 AO-96 2-M-96 49 12.899 123 12.488 31 A12-96 2-Jul-96 49 9.14 123 12.598 1 A14 2-M-96 49 5.73 123 12.35 1 HC1 2-Jul-96 49 12.5 123 15.09 1 HC2 2-Jul-96 49 13.05 123 14.95 1 HC3 2-Jul-96 49 13.49 123 14.95 1 HC4 2-Jul-96 49 13.99 123 14.96 1 HC5 2-Jul-96 49 14.38 123 14.96 1 HC6 2-Jul-96 49 12.7 123 13.03 1 HC7 2-Jul-96 49 12.5 123 13.67 1 HC8 2-Jul-96 49 12.41 123 14.15 1 HC9 2-M-96 49 12.28 123 14.7 1 HC10 2-M-96 49 12.58 123 12.75 1 HC11 2-M-96 49 12.4 123 13.11 1 HC12 2-M-96 49 12.17 123 13.35 1 HC13 2-Jul-96 49 12.01 123 13.77 1 HC14 2-M-96 49 12.5 123 12.37 1 HC15 2-Jul-96 49 12.31 123 12.53 1 HC16 2-M-96 49 12.11 123 12.69 1 HC17 2-Jul-96 49 11.82 123 12.82 1 169 Table A2.3 Location of cores and surface samples collected by the Institute of Ocean Sciences ("59" cores) and Simon Fraser University. Date of collection is indicated. Water depths for the "59" cores and coordinates for samples W l - l a , Wl-2a, Wl-3a, BPt-la, BPt-2a, BPt-3a, A14a-1 and A14b-1 were determined from a bathymetry map of the Strait of Georgia (L/C-3463), Canadian Hydrographic Service. Core Date Latitude (N) Longitude (W) 5903 (STN A) 3-Nov-93 49 17.5 123 23.5 5904 (STN 17) 2-Nov-93 49 16.85 123 22.1 5912 (STN 31) l-Nov-93 49 15.41 123 23.57 5911 (STN 21) 2-Nov-93 49 14.12 123 21.8 W l - l a Jul-Aug-95 49 4.70 123 11.80 Wl-2a Jul-Aug-95 49 4.10 123 13.00 Wl-3a Jul-Aug-95 49 3.50 123 14.35 W6-1 Jul-Aug-95 49 12.48 123 13.66 W7-1 Jul-Aug-95 49 11.57 123 14.34 W8-1 Jul-Aug-95 49 10.189 123 14.399 W9-1 Jul-Aug-95 49 9.34 123 14.34 W10-1 Jul-Aug-95 49 8.35 123 14.19 BPt-la Jul-Aug-95 49 2.85 123 8.0 BPt-2a Jul-Aug-95 49 2.40 123 8.7 BPt-3a Jul-Aug-95 49 2.00 123 9.3 A0-1 Jul-Aug-95 49 12.899 123 12.488 AO-2 Jul-Aug-95 49 12.899 123 12.488 A0-3 Jul-Aug-95 49 12.899 123 12.488 AlO-1 Jul-Aug-95 49 11.501 123 13.292 A10-2 Jul-Aug-95 49 11.501 123 13.292 A12-1 Jul-Aug-95 49 9.14 123 12.598 A14-1 Jul-Aug-95 49 5.73 123 12.35 A14-2 Jul-Aug-95 49 5.73 123 12.35 A14-3 Jul-Aug-95 49 5.73 123 12.35 A14a-1 Jul-Aug-95 49 5.60 123 14.10 A14b-1 Jul-Aug-95 49 5.30 123 15.80 170 Appendix 3: Sample Descriptions 171 Table A3.1 Description of core and grab samples (gs) collected from the Strait of Georgia. Sample Depth Interval Description VG1 0-1 0-1 cm Light brown, fine-grained throughout core VG2 0-1 0-1 cm Light brown, fine grained VG3 0-1 0-1 cm Light brown, fine grained VG4 0-1 0-1 cm Light brown, fine grained VG5 0-1 0-1 cm Brown, fine-grained SGI 0-1 0-1 cm Brown, fine-grained, worm tubes, good interface SG2 0-1 0-1 cm Brown, patches of reddish brown (Mn02)fine-grained, worm tubes, grey 9-10 cm, black, 22-24 cm, fine black particles 30-35 cm SG3 0-1 0-1 cm Areas of reddish brown (MnC«2), good interface, a live clam at 2-3 cm SG4 0-1 0-1 cm Good interface, fine fluff, worm at 3-4 cm, dark grey at 6-7 cm, dark grey-black at 40-45 cm SG5 0-1 0-1 cm Brown, fluffy, good interface, worm tubes, heart urchin at 1-2 cm SG6 0-1 0-1 cm Brown/grey SG7 0-1 0-1 cm Full half shell at 4-5 cm SG8 0-1 0-1 cm Brown/grey, worm at 1-2 cm SG9 0-1 0-1 cm Grey/green, worm tube down to 15 cm, worm at 4-5 cm SG10 0-1 0-1 cm SG11 0-1 0-1 cm Disturbed interface, worm at 2-3 cm SG12 0-1 0-1 cm Tilted interface, worm tube SG13 0-1 0-1 cm Good interface (slightly tilted), worm tube SG14 0-1 0-1 cm Grit SG15 0-1 0-1 cm Clam at 4-5 cm, black grit and sand at 5-6 cm SG16 0-1 0-1 cm Slanted interface, worm tube at 3-4 cm, worms at 4-6 cm SG17 0-1 0-1 cm Slumped interface,worm, putrid smell at 1-2 cm, black grey at 6-7 cm SG18 0-1 0-1 cm Fine dark material at 3-4 cm, worm at 6-7 cm SG19 0-1 0-1 cm Good interface, worm at 1-2 cm SG20 0-1 0-1 cm Fine grained, interface disturbed, worm tubes visible above the surface SG21 0-1 0-1 cm SG22 0-1 0-1 cm Brown/grey, interface slanted slightly, pieces of wood, fine fibres SG23 0-1 0-1 cm Worm tube, fine fibres ( -1.5 cm) from 1-4 cm | 172 Sample Depth Interval Description SG24 0-1 0-1 cm Brown, fluffy, black spot at 2-4 cm, wood fibres at 3-4 cm, grit at 5-6 cm, worms 6-7 cm SG25 0-1 0-1 cm Sand, black/grey at 1-2 cm, shells and worms at 2-3 cm SG26 0-1 0-1 cm Sand and worm at 2-3 cm SG27 0-1 0-1 cm Grit, clam shells at 1-2 cm, twig and wood fibres at 5-6 cm SG28 0-1 0-1 cm Shells at 4-5 cm SG29 0-1 0-1 cm Slanted interface, wood at 5-6 cm SG30 0-1 0-1 cm SG31 0-1 0-1 cm SG32 0-1 0-1 cm SG39 0-1 0-1 cm Shells SG40 0-1 0-1 cm Shells SG41 0-1 0-1 cm SG42 0-1 0-1 cm SG43 0-1 0-1 cm SG44 0-1 0-1 cm Heart urchin at 2-3 cm SG45 0-1 0-1 cm Worm tubes from 1-7 cm SG46 0-1 0-1 cm SG47 0-1 0-1 cm SG48 0-1 0-1 cm Wood debris at 4-5 cm, worm at 15 cm to 40 cm SG49 0-1 0-1 cm SG50 0-1 0-1 cm Grit SG51 0-1 0-1 cm Piece of black solid material-like charcoal, solid material at 4-5 cm, wood from 6-10 cm, worm (slug-like) at 24-26, worm (white with red spots on its side) at 28-30 cm SG52 0-1 0-1 cm Fine-grained brown sediment, throughout core SG53 0-1 0-1 cm Heart urchin at 2-3 cm, worm at 9-10 cm SG54 0-1 0-1 cm A few organisms SG55 0-1 0-1 cm Fine-grained brown, FeMn oxides, sloped interface, light brown and fine-grained sediment throughout core except 4-5 cm and 35-40 some black areas (FeS), at bottom of core dark sediment SG56 0-1 0-1 cm Brown, FeMn oxides, fine material, a few organisms, worm and worm tubes at 5-6 cm SG57 0-1 0-1 cm Solid worm tube at 2-4 cm, grey and olive green sediment at 4-7 cm SG58 0-1 0-1 cm Brown fluff (Fe Mn oxides), greenish sediment at 1-2 cm SG59 0-1 0-1 cm Brown fluff (FeMn oxides) 173 Sample Depth Interval Description AG1 0-2 0-2 cm Clay AG2 0-2 0-2 cm Clay AG3 0-2 0-2 cm Clay AG4 0-2 0-2 cm Clay, shells AG5 0-2 0-2 cm Clay AG6 0-2 0-2 cm Clay, shells AG7 0-2 0-2 cm Clay AG8 0-2 0-2 cm Clay AG9 0-2 0-2 cm Clay, shells AGlO-gs 0-2 cm Silt, dark grey particles, wood, shells A G 11 0-2 0-2 cm Silt, dark grey particles, white shells A G l l - g s 0-2 cm Silt, dark grey particles, white shells AG12-gs 0-2 cm Silt, dark grey particles, white shells-larger in size A G 13 0-2 0-2 cm Silty clay AG13-gs 0-2 cm Silty clay AG14 0-2 0-2 cm Silty clay AG15 0-2 0-2 cm Silty clay, white shells A G 16 0-2 0-2 cm Silty clay A G 17 0-1 0-1 cm Fine-grained, shell AG17 1-2 1-2 cm Fine-grained, shell A G 17 2-3 2-3 cm Fine-grained, shell A G 17 3-4 3-4 cm Fine-grained, shell A G 17 4-5 4-5 cm Fine-grained, shell AG17 5-6 5-6 cm Fine-grained, shell A G 17 6-7 6-7 cm Fine-grained, wood (removed) AG17 7-8 7-8 cm Fine-grained, shell, pebble (~5 mm) (removed) AG17 8-9 8-9 cm Fine-grained, shells AG17 9-10 9-10 cm Fine-grained, shells AG17 10-12 10-12 cm Fine-grained, shells AG17 12-14 12-14 cm Fine-grained AG17 14-16 14-16 cm Fine-grained AG17 16-18 16-18 cm Fine-grained AG17 18-20 18- 20 cm Fine-grained AG17 20-22 20-22 cm Fine-grained, shells AG17 22-24 22-24 cm Fine-grained A G 17 24-26 24-26 cm Fine-grained AG17 26-28 26-28 cm Fine-grained AG17 28-31 28-31 cm Fine-grained 174 Sample Depth Interval Description AG18 0-1 0-1 cm Silty clay AG19 0-1 0-1 cm Silty clay AG20 0-1 0-1 cm Silty clay AG21 0-1 0-1 cm Silty clay, dark grey particles, a piece of charcoal, fibres AG22 0-1 0-1 cm Silty clay AG23 0-1 0-1 cm Silty clay AG24 0-1 0-1 cm AG25 0-1 0-1 cm Twig AG26 0-1 0-1 cm Twigs, charcoal AG27 0-1 0-1 cm Twigs, wood, shells AG28 0-1 0-1 cm Wood fibres AG29 0-1 0-1 cm Twigs, shells, fishbone AG30 0-1 0-1 cm Pieces of wood (removed) AG31 0-1 0-1 cm Silty clay, shells, wood AG32 0-1 0-1 cm Clay, dark grey particles AG33 0-1 0-1 cm Clay, dark grey particles AG34 0-1 0-1 cm Fine-grained AG35 0-1 0-1 cm Fine-grained AG36 0-1 0-1 cm Fine-grained AG37 0-1 0-1 cm Fine-grained AG38 0-1 0-1 cm Fine-grained AG39 0-1 0-1 cm Fine-grained AG40 0-1 0-1 cm Charcoal, rock chip (removed) AG41 0-1 0-1 cm Clay, shells, wood AG42 0-1 0-1 cm Wood (removed two pieces) AG43 0-1 0-1 cm Wood, shells AG44 0-1 0-1 cm Dark grey particles, wood, shells AG45 0-1 0-1 cm Fine-grained AG46 0-1 0-1 cm Fine-grained AG47 0-1 0-1 cm Fine-grained AG48 0-1 0-1 cm Fine-grained AG49 0-1 0-1 cm Fine-grained AG50 0-1 0-1 cm Fine-grained AG51 0-1 0-1 cm Fine-grained AG52 0-1 0-1 cm Fine-grained AG53 0-1 0-1 cm Fine-grained 175 Sample Depth Interval Description AG54 0-1 0-1 cm Fine-grained, brown AG54 1-2 1-2 cm Fine-grained, worm tubes, yellow-orange spots, wood or worm AG54 2-3 2-3 cm Fine-grained, shells, wood or worm AG54 3-4 3-4 cm Fine-grained, shell, yellow-orange spots, fir tree needle AG54 4-5 4-5 cm Fine-grained, yellow-orange spots AG54 5-6 5-6 cm Fine-grained, yellow-orange spots around tube holes AG54 6-7 6-7 cm Fine-grained, yellow-orange spots around tube holes AG54 7-8 7-8 cm Fine-grained, yellow-orange spots around tube holes AG54 8-9 8-9 cm Fine-grained, a few yellow-orange colored pieces of clay AG54 9-10 9-10 cm Fine-grained, a few yellow-orange colored pieces of clay AG54 10-12 10-12 cm Fine-grained, one yellow-orange spot, wood/worm AG54 12-14 12-14 cm Fine-grained, wood or worm AG54 14-16 14-16 cm Fine-grained, orange color AG54 16-18 16-18 cm Fine-grained AG54 18-20 18- 20 cm Fine-grained AG54 20-22 20-22 cm Fine-grained AG54 22-24 22-24 cm Fine-grained AG54 24-26 24-26 cm Fine-grained AG54 26-28 26-28 cm Fine-grained AG54 28-30 28-30 cm Fine-grained AG54 30-35 30-35 cm Fine-grained AG54 35-40 35-40 cm Fine-grained AG54 40-45 40-45 cm Fine-grained AG54 45-50 45-50 cm Fine-grained AG54 50-55 50-55 cm Fine-grained AG54 55-60 55-60 cm Fine-grained AG54 60-65 60-65 cm Fine-grained AG54 65-67 65-67 cm Fine-grained, fibres AG55 0-1 0-1 cm Fine-grained AG56 0-1 0-1 cm Fine-grained AG57 0-1 0-1 cm Fine-grained AG58 0-1 0-1 cm Fine-grained, shells AG59 0-1 0-1 cm Fine-grained, shells 176 Table A3.2 Description of core samples collected from Sturgeon Bank and Roberts Bank. Sample Depth Interval Description A O 0-1 0-1 cm Light brown, fine-grained, shell A O 1-2 1-2 cm Pale brown, fine-grained A O 2-3 2-3 cm Fine-grained, black specks throughout rest core A O 3-4 3-4 cm Fine-grained, clay-silt A O 4-5 4-5 cm Fine-grained A O 5-6 5-6 cm Fine-grained, shells A O 6-7 6-7 cm Fine-grained, shells A O 7-8 7-8 cm Silty clay A O 8-9 8-9 cm Silty clay A O 9-10 9-10 cm Silty clay A O 10-12 10-12 cm Silty clay A O 12-14 12-14 cm Silty clay, wood A O 14-16 14-16 cm Silt, wood A O 16-18 16-18 cm Clay A O 18-20 18- 20 cm Silty clay A O 20-22 20-22 cm Fine sand-silt, wood A O 22-24 22-24 cm Fine sand A O 24-26 24-26 cm Fine sand A O 26-28 26-28 cm Fine sand A O 28-30 28-30 cm Fine sand A O 30-32 30-32 cm Fine sand, wood A12 0-1 0-1 cm Sand A12 1-2 1-2 cm Sand A12 2-3 2-3 cm Sand A12 3-4 3-4 cm Sand A12 4-5 4-5 cm Sand, shells A12 5-6 5-6 cm Sand A12 6-7 6-7 cm Silty sand A12 7-8 7-8 cm Sandy silt, wood fibres A12 8-9 8-9 cm Silty sand, wood, shells A12 9-10 9-10 cm Silty sand, wood A12 10-12 10-12 cm Sandy silt A12 12-14 12-14 cm Silt A12 14-16 14-16 cm Sandy silt, wood fibres, shell A12 16-18 16-18 cm Sandy silt, shells A12 18-20 18- 20 cm Silt, shell A12 20-22 20-22 cm Silt A12 22-24 22-24 cm 177 Sample Depth Interval Description KA10-1 0-1 cm Silty clay K A 2 0-1 0-1 cm Silty sand W6 0-1 0-1 cm Silty clay W7 0-1 0-1 cm Sand W8 0-1 0-1 cm Sand BPt-1 0-1 0-1 cm Brown, sand BPt-1 3-4 3-4 cm Dark grey (black), silt BPt-1 14-16 14-16 cm Dark grey (black, some brown), clay BPt-1 31-36 31-36 cm Dark grey, very fine sand, shells A10 0-1 0-1 cm Medium sand, brown, seaweed near the location A10 3-4 3-4 cm Medium sand, brown A10 14-16 14-16 cm Medium sand, grey, shell A10 26-31 26-31 cm Medium sand, dark grey AO 0-1 0-1 cm Clay, brown, (grey tube holes) AO 3-4 3-4 cm Clay, light grey, some black AO 14-16 14-16 cm Silt, dark grey some black AO 26-31 26-31 cm Medium sand, dark grey, some black A12 0-1 0-1 cm Sand A14 0-1 0-1 cm Clay H C l 0-1 0-1 cm Sand HC2 0-1 0-1 cm Sand HC3 0-1 0-1 cm Sand HC4 0-1 0-1 cm Sand HC5 0-1 0-1 cm Sand HC6 0-1 0-1 cm Fine sand HC7 0-1 0-1 cm Clay HC8 0-1 0-1 cm Clay-some silt, shells HC9 0-1 0-1 cm Silt, black particles HC10 0-1 0-1 cm Clay, shells HC11 0-1 0-1 cm Clay HC12 0-1 0-1 cm Clay-some silt HC13 0-1 0-1 cm Fine sand HC14 0-1 0-1 cm Clay-some silt HC15 0-1 0-1 cm Clay-some silt, near airport runway lights HC16 0-1 0-1 cm Clay-silt, shell HC17 0-1 0-1 cm Clay, shells, near marsh grass, green foam on the surface 178 Table A3.3 Description of core and surface samples collected by the Insitute of Ocean Sciences ("59" cores) and Simon Fraser University. Sample Depth Interval Description 5903-01 0-1 cm Fine-grained 5903-02 1-2 cm Fine-grained 5903-03 2-3 cm Fine-grained 5903-04 3-4 cm Fine-grained 5903-05 4-5 cm Fine-grained 5903-06 5-6 cm Fine-grained 5903-07 6-7 cm Fine-grained 5903-08 7-8 cm Fine-grained 5903-09 8-9 cm Fine-grained 5903-11 10-12 cm Fine-grained 5903-13 14-16 cm Fine-grained 5903-15 18-20 cm Fine-grained 5903-17 22-24 cm Shell, pebble 5903-19 26-28 cm Dense particles (-0.5 mm) 5903-21 30-35 cm Dense particles 5903-22 35-40 cm Dense particles 5903-23 40-45 cm 5903-24 45-50 cm 5904-01 0-1 cm 5904-02 1-2 cm Shell, fine fibres 5904-03 2-3 cm Fine fibres, granule (-3x5 mm) 5904-04 3-4 cm Shells 5904-05 4-5 cm 5904-06 5-6 cm 5904-07 6-7 cm Shells, dense particles (- lxlmm), pebble (~7xl0mm) 5904-08 7-8 cm 5904-09 8-9 cm 5904-11 10-12 cm Dark brown fibres 5904-13 14-16 cm 5904-15 18-20 cm Dark brown fibres 5904-17 22-24 cm 5904-19 26-28 cm Brown fibres, wood 5904-21 30-35 cm Shells, fine fibres 5904-22 35-40 cm Shells, dense particles 5904-23 40-45 cm 5904-24 45-50 cm Dense particles 179 Sample Depth Interval Description 5911-01 0-1 cm 5911-02 1-2 cm 5911-03 2-3 cm Shell 5911-04 3-4 cm 5911-05 4-5 cm 5911-06 5-6 cm 5911-07 6-7 cm 5911-08 7-8 cm Shell 5911-09 8-9 cm 5911-11 10-12 cm Shell 5911-13 14-16 cm Shell, dense particles 5911-15 18-20 cm Full half shell 5911-17 22-24 cm Shell 5911-19 26-28 cm 5911-21 30-35 cm 5911-22 35-40 cm 5911-23 40-45 cm 5911-24 45-50 cm 5912-01 0-1 cm Wood fibres 5912-02 1-2 cm Piece of wood and wood fibres 5912-03 2-3 cm 5912-04 3-4 cm 5912-05 4-5 cm 5912-06 5-6 cm Wood fibres 5912-07 6-7 cm Wood fibres 5912-08 7-8 cm 5912-09 8-9 cm 5912-11 10-12 cm Shell, wood, dense particles 5912-13 14-16 cm Shell, wood, pebble 5912-15 18-20 cm Wood, dense particles 5912-17 22-24 cm Shell, wood, dense particles 5912-19 26-28 cm Shell, wood, dense particles 5912-21 30-35 cm Pebble 5912-22 35-40 cm Shell, wood 5912-23 40-45 cm Fine-grained 5912-24 45-50 cm Fine-grained 180 Sample Depth Interval Description W l - l a Surface Fine Wl-2a Surface Sand Wl-3a Surface Sand W6-1 Surface Silt W7-1 Surface Sand W8-1 Surface Sand W9-1 Surface Sand W10-1 Surface Sand BPt-la Surface Fine BPt-2a Surface Fine BPt-3a Surface Fine AO-1 Surface Fine AO-2 Surface Fine AO-3 Surface Fine A10-1 Surface Sand A10-2 Surface Sand A12-1 Surface Sand A14-1 Surface Fine A14-2 Surface Fine A14-3 Surface Fine A14a-1 Surface Sand A14b-1 Surface Fine 181 Appendix 4: Data 182 Table A4.1 Ag, Pb, 8 1 3 Corg, 8 1 5 N , Corg, Cinorg, total carbon, nitrogen and sulphur, C /N and CI in surface samples from the Strait of Georgia. Values are on a salt free basis, except for chlorine and isotopes of carbon and nitrogen. Isotopes of carbon are relative to PDB and nitrogen to air. The detection for N was approximately 0.05% (<D.L.=less than detection limit). Sample Ag (ppb) Pb-lCP (ppm dl5N(0/00) dl3C(0/00) Corg (wt. %) Cinorg (wt. %) Ntot (wt. %) Ctot (wt. %) Stot (wt. %) C/N CI (wt. %) 5903 273 21.81 5.84 -23.12 1.72 0.11 o.n * 1.83 0.08 10.04 3.51 5904 212 24.45 5.50 -23.02 1.86 0.11 0.16 1.97 0.10 11.73 2.99 5911 238 16.33 6.20 -23.01 1.80 0.12 0.18 1.91 0.07 9.88 3.55 5912 215 17.19 5.74 -23.79 2.64 0.10 0.20 2.74 0.07 13.17 4.59 VG1 223 4.48 -22.35 1.69 0.11 0.22 1.80 0.13 7.86 4.05 VG2 300 15.15 5.25 -22.13 1.81 0.10 0.18 1.90 0.17 9.81 3.34 VG3 234 14.11 4.47 -22.25 1.74 0.12 0.18 1.86 0.14 9.91 4.10 VG4 224 15.31 5.70 -22.15 1.82 0.08 0.19 1.90 0.14 9.38 3.88 VG5 203 16.45 5.68 -21.76 1.98 0.08 0.22 2.05 0.13 9.13 4.98 SGI 178 13.61 5.34 -21.70 1.53 0.10 0.17 1.63 0.14 8.94 2.73 SG2 187 15.09 5.59 -22.05 1.71 0.10 0.19 1.82 0.13 9.18 3.50 SG3 181 16.08 5.36 -21.89 1.80 0.10 0.20 1.90 0.10 9.09 4.28 SG4 184 16.53 5.53 -21.84 1.63 0.10 0.19 1.74 0.09 8.40 4.45 SG5 254 16.98 4.44 -21.97 1.73 0.08 0.19 1.81 0.09 9.18 4.46 SG6 201 16.26 5.48 -22.15 1.62 0.09 0.17 1.71 0.09 9.48 3.86 SG7 213 15.24 5.59 -21.95 1.93 0.09 0.21 2.03 0.08 9.20 4.49 SG8 209 14.59 5.53 -22.22 1.44 0.09 0.16 1.54 0.10 9.25 2.99 SG9 231 13.81 4.77 -22.56 1.45 0.13 0.15 1.58 0.10 9.42 3.32 SG10 291 14.28 4.81 -22.60 1.32 0.22 0.15 1.54 0.10 8.57 3.02 SG11 301 15.65 4.45 -22.96 1.33 0.14 0.14 1.48 0.09 9.70 2.86 SG12 356 13.03 4.57 -23.05 1.25 0.15 0.13 1.40 0.10 9.90 2.45 SG13 267 11.12 4.12 -23.41 0.95 0.11 0.09 1.06 0.06 10.60 1.76 SG14 174 8.07 3.63 -23.76 0.94 0.12 0.09 1.07 0.07 10.95 1.51 SG20 248 14.13 5.02 -22.46 1.85 0.09 0.18 1.95 0.18 10.12 2.86 SG19 330 13.87 4.98 -22.62 1.73 0.08 0.17 1.81 0.16 10.21 2.87 SG18 436 14.19 4.14 -22.93 1.51 0.11 0.15 1.62 0.13 10.14 2.47 SG17 524 12.51 3.42 -23.25 1.34 0.11 0.12 1.45 0.11 11.27 2.07 SG16 447 12.19 3.2 -23.34 1.03 0.09 0.10 1.12 0.09 10.68 1.55 SG15 289 10.22 3.25 -23.47 0.98 0.10 0.09 1.08 0.12 10.73 1.30 SG21 264 13.69 4.52 -22.42 1.94 0.12 0.19 2.06 0.18 10.43 3.03 SG22 426 13.18 4.58 -22.69 1.94 0.11 0.18 2.05 0.17 10.88 3.02 SG23 743 14.75 3.83 -23.07 1.49 0.12 0.14 1.61 0.09 10.57 2.23 SG24 724 14.94 3.14 -23.48 1.08 0.09 . 0.10 1.17 0.09 11.30 1.48 SG25 497 11.76 2.52 -23.66 1.10 0.11 0.09 1.21 0.09 12.86 1.32 SG26 268 9.17 3.24 -23.70 0.61 0.10 0.06 0.71 0.02 10.02 2.34 SG32 287 14.47 4.55 -22.31 1.76 0.07 0.18 1.84 0.15 9.63 3.42 SG31 450 14.47 3.76 -22.34 1.59 0.08 0.16 1.68 0.10 10.25 2.90 SG30 850 15.63 4.38 -23.05 1.50 0.10 0.15 1.61 0.13 10.23 2.69 SG29 771 15.53 2.664 -23.32 1.94 0.12 0.11 2.05 0.14 17.00 2.07 SG28 555 10.94 3.05 -22.74 1.54 0.11 0.14 1.65 0.19 11.36 1.50 SG27 410 11.31 2.83 -22.70 1.25 0.09 0.10 1.34 0.15 12.03 1.37 SG44 280 22.27 4.62 -22.57 1.69 0.09 0.16 1.78 0.12 10.50 3.02 SG43 438 16.18 4.15 -23.03 1.51 0.12 0.14 1.63 0.12 10.72 2.79 SG42 606 15.67 3.87 -22.99 1.54 0.13 0.15 1.67 0.12 10.08 2.75 SG41 635 20.57 3.26 -23.34 1.36 0.11 0.13 1.46 0.13 10.58 . 1.90 SG40 567 12.79 2.57 -23.64 1.12 0.13 0.11 1.25 0.10 10.60 1.74 SG39 399 11.76 2.94 -23.40 0.95 0.08 0.09 1.04 0.13 10.91 1.46 183 Sample Ag (ppb) Pb-ICP (ppm) J15N (0/00) J13C (0/00) Corg (wt. %) Cinorg (wt. %) Ntot (wt. %) Ctot (wt. %) Stot (wt. %) C/N CI (wt. %) SG45 279 15.60 4.53 -22.59 1.71 0.09 0.17 1.80 0.13 10.26 2.67 SG46 454 14.84 4.42 -22.67 1.61 0.07 0.15 1.68 0.12 10.91 2.80 SG47 686 14.85 3.3 -23.19 1.42 0.15 0.14 1.57 0.12 10.41 2.32 SG48 630 13.80 3.38 -23.84 1.25 0.09 0.11 1.34 0.09 11.89 1.82 SG49 544 11.85 3.81 -23.53 0.81 0.34 0.09 1.15 0.08 9.04 1.62 SG50 430 11.31 3.49 -23.66 2.01 0.10 0.18 2.11 0.26 11.10 1.65 SG51 255 19.64 4.91 -22.68 0.89 0.08 0.07 0.97 0.01 12.79 3.04 SG52 262 20.24 4.8 -22.41 1.71 0.10 0.15 1.82 0.14 11.25 3.41 SG53 188 20.74 5.25 -22.04 1.71 0.08 0.18 1.79 0.11 9.77 3.51 SG54 140 20.83 6.11 -21.17 2.31 0.10 0.26 2.41 0.16 9.01 7.91 SG55 104 14.07 5.78 -21.95 2.06 0.08 0.24 2.14 0.15 8.72 3.71 SG56 129 24.47 6.02 -21.54 2.64 0.07 0.27 2.71 0.12 9.93 5.61 SG57 139 20.73 5.55 -21.77 1.76 0.08 0.19 1.84 0.14 9.41 4.51 SG58 160 18.11 5.77 -21.67 1.95 0.07 0.20 2.02 0.15 9.73 5.50 SG59 142 19.32 5.62 -21.62 1.97 0.08 0.22 2.05 0.09 9.17 5.05 A O 1,303 21.96 3.79 -22.81 1.59 0.06 0.05 1.64 0.36 33.70 0.66 KA1 321 12.85 4.91 -21.95 0.49 0.10 <D.L. 0.59 0.03 0.39 KA2 96 4.55 -22.04 0.44 0.03 <D.L. 0.47 0.03 0.27 W6 449 14.18 4.81 -22.25 0.64 0.08 <D.L. 0.72 0.07 0.42 W7 49 14.18 2.71 -21.59 0.14 0.01 <D.L. 0.16 0.02 0.27 W8 51 2.85 -21.97 0.12 0.01 <D.L. 0.13 0.01 0.26 A12 65 2.68 -22.18 0.20 0.01 <D.L. 0.21 0.02 0.29 Wl- la 142 0.85 0.04 0.10 0.89 0.03 8.86 0.28 Wl-2a 76 6.99 0.35 0.03 <D.L. 0.38 0.00 0.27 Wl-3a 55 6.82 0.12 0.02 <D.L. 0.14 0.00 0.30 W6-1 447 0.41 0.04 <D.L. 0.45 0.03 0.29 W7-1 46 10.01 0.19 0.01 <D.L. 0.20 0.00 0.29 W8-1 47 4.63 0.13 0.01 <D.L. 0.14 0.00 0.29 W9-1 53 5.40 0.13 0.00 <D.L. 0.14 0.00 0.36 W10-1 51 6.25 0.14 0.03 <D.L. 0.17 0.00 0.30 BPt-la 196 1.62 0.19 0.18 1.81 0.07 8.87 0.66 BPt-2a 129 1.15 0.12 0.12 1.28 0.04 9.97 0.58 BPt-3a 119 1.15 0.14 0.14 1.29 0.04 8.21 0.53 AO-1 1,074 0.76 0.04 0.08 0.80 0.02 9.25 0.38 AO-2 1,500 0.91 0.05 0.10 0.96 0.13 9.40 0.36 AO-3 868 0.83 0.03 0.09 0.86 0.14 9.6 0.35 A10-1 63 9.61 0.19 0.01 <D.L. 0.20 0.00 0.29 A10-2 62 8.54 0.18 0.02 <D.L. 0.20 0.00 0.33 A12-1 42 11.89 0.14 0.01 <D.L. 0.15 0.00 0.36 A14-1 109 0.57 0.05 <D.L. 0.62 0.01 0.27 A14-2 112 0.61 0.06 0.06 0.67 0.00 10.49 0.32 A14-3 129 0.69 0.11 0.06 0.80 0.00 10.93 0.28 A14a-1 61 9.56 0.21 0.02 <D.L. 0.23 0.00 0.32 A14b-1 101 0.50 <D.L. 0.50 0.00 0.30 BPt-1 79 10.76 4.62 -22.98 0.72 0.13 <D.L. 0.85 0.05 0.66 A10 55 9.52 4.42 -20.88 0.26 < D.L. 0.26 0.01 0.33 AO-96 888 19.30 4.23 -22.91 1.01 0.08 0.09 1.09 0.16 10.74 0.66 A12-96 49 9.09 4.65 -21.55 0.19 <D.L. 0.19 0.01 0.32 A14 113 7.41 2.67 -24.70 0.68 0.04 <D.L. 0.72 0.02 0.25 HC1 67 5.09 3.08 -21.45 0.2C 0.02 <D.L. 0.21 0.02 0.42 HC2 56 7.44 3.72 -22.12 0.16 0.01 <D.L. 0.16 0.01 0.38 HC3 53 7.52 3.82 -22.41 0.14 <D.L. 0.15 0.01 0.38 HC4 45 7.63 4.62 -22.92 0.15 <D.L. 0.15 O.OO 0.43 HC5 44 5.2C 2.97 -21.92 COS 0.01 <D.L. 0.09 0.02 0.29 184 Sample ^g;(ppb) >b (ppm) J15N (0/00) dl3C(0/00) "org (wt. %) "inorg (wt. %) Ntot (wt. %) Ctot (wt. %) Stot (wt. %) ~/N JoC\ HC6 345 10.83 4.71 -21.01 0.25 <D.L. 0.25 0.04 0.49 HC7 289 13.50 4.39 -22.85 0.79 0.04 0.07 0.83 0.08 11.12 0.60 HC8 265 10.95 4.24 -22.54 0.48 0.03 <D.L. 0.51 0.03 0.46 HC9 | 112 8.79 3.77 -22.63 0.24 0.01 <D.L. 0.25 0.02 0.37 HC10 1,436 14.30 4.29 -23.06 0.92 0.04 0.08 0.96 0.17 11.32 0.59 HC11 585 18.12 4.33 -22.78 0.80 0.04 0.07 0.84 0.08 11.48 0.59 HC12 628 13.05 4.28 -22.30 0.60 0.03 <D.L. 0.63 0.04 0.39 HC13 92 10.91 4.55 -21.08 0.24 0.01 <D.L. 0.25 0.01 0.39 H C l 4 513 10.35 4.47 -22.34 0.63 0.04 0.06 0.67 0.10 11.44 0.43 HC15 434 23.61 4.41 -22.35 0.63 0.03 0.06 0.66 0.09 10.33 0.43 HC16 417 11.50 4.35 -22.19 0.45 0.02 <D.L. 0.47 0.06 0.35 HC17 : 540 12.89 4.36 -22.44 0.81 0.04 0.08 0.86 0.12 10.00 0.44 AG1 218 12.34 3.9 -23.35 1.59 0.09 0.14 1.68 0.15 11.12 2.57 AG2 245 13.01 3.66 -23.44 1.57 0.07 0.13 1.64 0.12 11.98 2.20 AG3 ; 285 13.38 3.8 -23.66 1.65 0.08 0.14 1.73 0.14 11.99 2.63 AG4 ! 315 12.70 3.1 -23.80 1.47 0.08 0.12 1.55 0.11 12.04 2.14 AG5 i 322 13.00 2.85 -23.77 1.21 0.18 0.11 1.39 0.10 10.87 1.79 AG6 240 8.62 3.14 -23.95 0.99 0.05 0.08 1.04 0.09 12.85 1.34 AG7 150 8.94 3.4 -23.84 0.88 0.04 0.07 0.92 0.06 13.18 1.23 AG8 . 124 8.19 2.5 -24.57 0.44 0.45 0.06 0.89 0.06 7.09 1.25 AG9 222 9.45 2.92 -23.91 1.09 0.07 0.09 1.15 0.12 12.45 1.59 AGlOgs '< 127 5.46 2.15 -24.09 0.39 0.03 <D.L. 0.41 0.13 0.69 AG11 ', 196 13.00 2.99 -24.03 0.57 0.04 <D.L. 0.61 0.06 0.90 AGllgs i 127 5.73 0.36 0.04 <D.L. 0.41 0.11 0.66 AG12 143 7.03 3.05 -23.91 0.58 0.06 <D.L. 0.64 0.08 0.76 AG13 163 7.49 3.45 -23.45 0.71 0.12 0.06 0.83 0.06 11.46 1.03 AG13gs 222 9.38 3.34 0.7 0.08 <D.L. 0.78 0.06 0.96 A G 14 ! 231 9.07 3.7 -23.78 0.83 0.06 0.07 0.89 0.08 11.73 1.16 AG15 1 403 9.38 3.14 -23.76 0.95 0.06 0.09 1.01 0.11 10.81 1.44 A G 16 436 8.26 2.53 -23.71 1.05 0.05 0.09 1.10 0.12 11.50 1.48 AG17 ! 698 12.38 3.04 -23.96 1.3 0.09 0.11 1.39 0.15 12.22 1.83 AG18 > 497 11.46 3.12 -23.79 1.19 0.08 0.10 1.27 0.12 11.42 1.87 AG19 383 12.40 3.55 -23.83 0.91 0.12 0.08 1.03 0.10 10.92 1.32 AG20 363 12.78 3.36 -23.85 0.87 0.06 0.07 0.93 0.08 12.30 1.22 AG21 225 11.58 4.53 -23.69 0.81 0.05 0.06 0.86 0.07 12.55 1.16 AG22 196 10.82 4.12 -23.95 0.92 0.03 0.06 0.96 0.12 16.21 0.89 AG23 1 246 10.14 4.24 -23.62 0.97 0.04 0.07 1.02 0.07 13.74 1.26 AG24 321 11.79 3.35 -23.91 0.82 0.05 0.06 0.87 0.06 13.45 1.21 AG25 564 11.99 3.67 -23.69 0.99 0.05 0.08 1.03 0.08 12.19 1.41 AG26 202 11.73 3.33 -24.48 1.03 0.06 0.06 1.08 0.12 16.70 1.18 AG27 241 9.93 3.36 -24.26 0.82 0.03 <D.L. 0.85 0.07 17.31 0.90 AG28 j 342 8.04 4.01 -23.82 0.93 0.06 0.07 0.99 0.07 13.54 1.42 AG29 385 10.56 3.64 -23.81 0.87 0.05 0.07 0.92 0.06 13.16 1.22 AG30 371 13.30 3.85 -23.95 0.80 0.00 0.06 0.80 0.06 14.17 0.88 AG31 357 10.19 4.22 -23.92 1.23 0.09 0.08 1.31 0.10 16.16 1.12 AG32 591 19.90 4.82 -23.72 1.46 0.13 0.13 1.59 0.16 11.44 0.86 AG33 ; 366 15.61 5.31 -23.59 1.30 O.OS 0.12 1.39 0.10 11.15 2.35 AG34 ; 310 17.13 6.01 -23.21 1.7C 0.11 0.16 1.81 0.13 10.80 2.84 AG35 223 18.54 5.1S -23.02 1.75 O.OS o.n 1.85 0.11 10.58 3.64 AG36 i 246 18.57 6 -23.03 1.64 0.08 0.16 1.72 0.10 10.42 3.88 AG37 ' 347 15.8S 5.8' -22.83 1.7C 0.11 o.r 1.81 0.11 10.24 3.48 AG38 357 12.5' 5.0S -23.3C 1.52 0.1C 0.13 1.62 0.1C 11.37 2.89 AG39 [ 453 13.51: 3.9* -23.43 1.68 0.11 0.13 1.8C 0.08 12.76 2.28 AG40 51C 17.66 4.11 -24.3: 1.4i 0.1 0.1C 1.56 0.0' 13.96 1.79 185 Sample Ag (ppb) Pb(ppm) dl5N(0/00) dl3C (0/00) Corg (wt. %) Cinorg (wt. %) Ntot (wt. %) Ctot (wt. %) Stot (wt. %) C/N %C1 AG41 454 14.51 3.56 -24.34 1.13 0.12 0.08 1.26 0.08 14.11 1.37 AG42 338 11.39 3.45 -24.02 1.00 0.12 0.06 1.12 0.08 16.59 1.21 AG43 268 11.96 3.76 -24.23 1.01 0.13 0.06 1.15 0.07 17.63 1.05 AG44 297 10.15 3.68 -24.23 0.88 0.13 0.06 1.01 0.07 15.61 1.05 AG45 168 11.18 3.22 -24.51 0.84 0.18 <D.L. 1.02 0.08 0.98 AG46 367 16.42 4.46 -23.68 1.55 0.12 0.14 1.67 0.09 11.38 2.73 AG47 303 20.47 4.95 -23.09 1.66 0.12 0.15 1.78 0.09 10.99 3.26 AG48 297 19.01 4.62 -23.01 1.49 0.09 0.14 1.58 0.09 10.72 3.24 AG49 291 23.22 5.05 -23.20 1.66 0.09 0.16 1.75 0.09 10.42 3.10 AG50 285 18.18 5.07 -22.70 1.73 0.08 0.17 1.82 0.09 10.19 3.67 AG51 279 20.31 5.36 -22.80 1.79 0.10 0.18 1.89 0.10 9.91 3.92 AG52 273 17.46 5.43 -22.85 1.80 0.09 0.18 1.89 0.13 10.27 3.88 AG53 267 16.73 4.89 -22.95 1.71 0.09 0.16 1.79 0.10 10.51 3.97 AG54 391 17.66 5.51 -23.07 1.75 0.10 0.17 1.86 0.11 10.27 4.12 AG55 531 18.87 5.12 -23.48 1.89 0.10 0.16 1.99 0.14 11.53 3.62 AG56 619 17.77 4.95 -23.80 1.54 0.12 0.13 1.66 0.10 11.72 2.58 AG57 547 12.40 4.32 -23.75 1.39 0.15 0.12 1.55 0.09 11.63 2.20 AG58 461 14.25 4.58 -23.69 1.36 0.14 0.12 1.50 0.09 11.36 2.20 AG59 548 17.63 4.52 -23.98 1.47 0.15 0.11 1.62 0.10 13.82 2.06 186 Table A4.2 Minor element data and I/Corg ratios for surface samples from the Strait of Georgia. Values for I/Corg ratios are multiplied by 10 4. Values are on a salt free basis and units of ppm. The detection for Mo was approximately 3 ppm (<D.L.=less than detection limit). Note that iodine values less than 10 ppm are unreliable. Sample Zr Y Sr Rb Pb Zn Cu Ni Co Mn V Cr Ba I I/Corg (» lE+04) Mo 5903 125 19 267 76 29 127 56 50 16 895 154 110 583 93 54 <D.L 5904 140 18 298 62 10 110 40 44 16 1,278 147 104 562 89 48 <D.L 5911 139 18 264 73 21 117 43 49 13 849 156 116 584 96 53 <D.I_ 5912 125 16 292 72 13 111 46 48 18 1,616 147 n o 583 137 52 <D.L VG1 147 17 303 86 39 108 57 53 10 1,028 171 133 655 92 54 <D.L VG2 135 20 251 70 21 113 42 46 15 691 144 111 540 85 47 <D.L VG3 142 23 255 78 12 106 37 45 15 745 143 117 554 76 43 <D.L VG4 134 26 267 73 25 115 40 46 18 1,019 148 111 562 113 62 <D.L VG5 114 17 283 68 14 121 47 48 18 3,809 151 103 551 165 84 <D.L SGI 145 23 274 61 26 106 38 40 14 701 144 103 523 86 56 <D.L SG2 131 20 279 62 18 114 42 52 15 1,985 154 114 547 120 70 <D.L SG3 123 20 275 73 10 116 42 44 16 2,168 160 112 523 129 71 <D.L SG4 124 19 270 72 15 116 39 50 19 1,821 174 117 585 127 78 <D.L SG5 126 21 261 67 28 117 46 51 16 1,163 173 113 576 U l 64 <D.L SG6 129 16 275 76 25 118 44 52 16 1,109 177 121 628 105 65 <D.L SG7 133 23 274 63 18 115 45 53 18 1,221 151 113 531 135 70 <D.L SG8 146 22 271 67 16 109 42 46 17 708 162 122 592 69 48 <D.L SG9 146 22 272 59 9 109 42 49 13 718 159 133 609 61 42 <D.L. SG10 147 23 273 73 23 112 49 53 19 717 168 132 637 58 44 <D.L. SG11 149 21 261 73 4 107 43 51 17 680 163 128 628 47 35 <D.U SG12 156 19 266 72 11 113 45 53 15 649 150 131 638 42 33 <D.L SG13 179 17 285 63 19 98 40 48 17 663 139 128 637 19 20 <D.L SG14 170 25 270 54 9 92 34 51 16 681 137 138 634 19 20 <D.L SG20 145 21 263 69 8 112 45 53 15 656 168 126 629 59 32 <D.L SG19 146 22 265 76 15 109 47 52 11 719 168 133 658 67 39 <D.L SG18 155 27 266 66 18 112 48 53 16 636 165 130 670 41 27 <D.L SG17 166 21 268 65 9 104 47 55 15 671 164 145 665 24 18 <D.L. SG16 183 20 272 58 17 91 39 50 18 621 153 139 650 21 20 <D.L SG15 170 22 283 51 17 89 36 46 16 619 151 153 657 17 17 <D.L. SG21 140 22 257 64 12 111 49 47 15 648 163 122 613 66 34 <D.L SG22 143 24 254 68 22 113 50 55 17 659 172 127 656 58 30 <D.L SG23 156 19 263 ' 71 17 117 52 50 17 626 159 138 659 43 29 <D.L SG24 172 22 278 58 15 99 46 46 14 583 144 138 624 25 23 <D.L SG25 151 18 274 52 8 90 38 39 13 569 136 123 606 13 12 <D.L SG26 152 20 275 49 6 79 30 40 13 566 134 130 588 20 33 <D.L SG32 136 20 267 70 15 110 43 48 16 787 174 126 619 88 50 <D.L SG31 i43 25 261 77 9 112 49 53 20 685 175 132 659 63 40 <D.L SG30 155 21 267 76 30 114 55 51 19 655 173 133 656 49 32 <D.L SG29 170 20 265 62 14 106 49 50 17 633 170 155 665 31 16 <D.L SG28 174 22 269 52 14 92 35 42 16 602 157 157 638 18 12 <D.L SG27 175 22 276 56 6 85 32 42 16 612 154 151 642 15 12 <D.L. SG44 140 21 253 71 24 118 44 53 15 663 162 126 624 73 43 <D.L SG43 148 22 254 62 15 118 51 55 14 628 158 128 626 52 34 <D.L SG42 153 21 267 70 15 115 56 52 17 640 157 131 638 60 39 <D.L SG41 164 24 264 66 9 106 50 51 15 635 171 140 659 29 21 <D.L SG40 178 21 279 64 22 94 44 50 13 592 156 143 647 22 20 <D.L. SG39 178 22 275 49 8 95 44 46 15 616 155 140 647 21 22 <D.L 187 Sample Zr Y Sr Rb Pb Zn Cu Ni Co Mn V Cr Ba I I/Corg(*lE+04) Mo SG46 148 20 252 73 15 114 49 54 13 681 167 129 684 63 39 <D.L. SG47 155 29 266 71 14 114 51 52 14 646 171 136 671 43 31 <D.L. SG48 165 22 270 57 18 103 54 53 19 613 162 145 674 32 26 <D.L. SG49 168 21 274 54 16 93 42 43 14 606 156 143 619 25 31 <D.L. SG50 191 24 279 47 14 85 37 48 14 603 154 140 631 19 9 <D.L. SG51 129 22 266 69 22 114 48 50 19 707 171 123 635 94 105 <D.L. SG52 123 20 262 70 17 117 52 51 14 876 168 116 599 84 49 <D.L. SG53 125 19 294 78 25 120 50 47 18 1,054 165 109 599 151 88 <D.L. SG54 93 23 333 82 20 141 52 51 20 16,743 147 86 456 291 126 10 SG55 97 21 299 76 19 133 45 56 23 9,475 171 94 549 189 92 <D.L. SG56 96 23 298 71 23 157 55 55 28 5,028 162 96 527 250 95 <D.L. SG57 111 24 275 77 26 135 51 56 19 2,207 164 112 611 160 91 <D.L. SG58 110 22 268 73 10 121 44 55 18 4,220 174 106 565 164 84 <D.L. SG59 107 17 288 71 5 129 46 52 18 6,222 177 104 580 185 94 <D.L. A O 191 22 281 58 23 105 46 46 14 597 147 151 661 11 7 <D.L. KA1 227 19 281 43 8 84 26 44 36 614 135 164 592 11 22 <D.L. KA2 225 19 271 28 10 71 14 35 43 673 132 166 537 6 13 <D.L. W6 165 16 274 50 10 88 30 40 60 644 126 125 598 12 19 <D.L. W7 215 23 275 34 12 66 14 37 54 759 131 191 534 5 36 <D.L. W8 167 16 266 26 8 59 11 36 62 636 111 134 529 5 41 <D.L. A12 80 18 253 29 16 61 12 27 117 644 104 91 504 9 44 <D.L. 188 Table A4.3 Major element data for surface samples from the Strait of Georgia. Values are on a salt free basis and in units of weight percent. Sampl Fe Mn Ti Ca K Si Al Mg P Na 5903 4.26 0.07 0.45 1.50 1.46 25.93 7.72 1.66 0.14 1.78 5904 3.76 0.09 0.44 1.66 1.36 27.00 7.31 1.39 0.12 1.94 5911 4.21 0.07 0.47 1.56 1.54 26.61 7.51 1.60 0.13 2.04 5912 4.09 0.12 0.45 1.55 1.37 26.55 7.50 1.49 0.16 1.98 VG1 4.21 0.07 0.50 1.63 1.38 26.96 7.86 1.78 0.14 1.79 VG2 4.16 0.06 0.49 1.57 1.36 26.25 7.55 1.58 0.12 1.44 VG3 4.02 0.06 0.49 1.68 1.31 26.83 7.52 1.60 0.12 1.53 VG4 4.19 0.07 0.48 1.54 1.40 26.08 7.41 1.50 0.14 2.08 VG5 4.24 0.29 0.45 1.35 1.24 25.35 7.50 1.58 0.14 1.31 SGI 3.76 0.06 0.48 1.68 1.40 26.62 7.28 1.47 0.11 2.01 SG2 4.24 0.15 0.47 1.52 1.29 26.80 7.75 1.59 0.13 1.78 SG3 4.19 0.17 0.47 1.44 1.23 25.73 7.32 1.58 0.14 1.56 SG4 4.34 0.13 0.46 1.38 1.40 25.43 7.06 1.46 0.13 1.43 SG5 4.19 0.08 0.46 1.39 1.31 25.63 7.51 1.58 0.12 0.74 SG6 4.46 0.08 0.49 1.63 1.39 26.72 7.85 1.66 0.14 1.84 SG7 4.11 0.09 0.48 1.49 1.13 25.84 7.24 1.58 0.14 1.44 SG8 3.87 0.05 0.49 1.66 1.33 26.31 7.13 1.44 0.11 1.74 SG9 3.89 0.05 0.4S 1.63 1.33 26.04 7.19 1.59 0.12 1.38 SG10 4.04 0.06 0.51 1.68 1.41 26.87 7.62 1.62 0.12 1.92 SG11 4.03 0.06 0.49 1.69 1.51 26.27 7.39 1.53 0.11 1.72 SG12 3.91 0.05 0.49 1.75 1.53 26.62 7.39 1.58 0.11 1.55 SG13 3.48 0.05 0.46 1.84 1.35 28.06 6.76 1.48 0.09 1.34 SG14 3.47 0.06 0.46 1.81 1.54 28.71 6.68 1.48 0.08 1.49 SG20 3.98 0.05 0.49 1.58 1.40 25.68 7.40 1.44 0.12 1.45 SG19 4.17 0.06 0.49 1.62 1.50 25.61 7.33 1.50 0.12 1.39 SG18 4.12 0.05 0.50 1.64 1.48 26.23 7.56 1.64 0.11 1.71 SGI 7 3.85 0.05 0.49 1.77 1.42 27.61 7.27 1.61 0.10 1.14 SG16 3.47 0.05 0.47 1.99 1.45 28.75 6.70 1.41 0.09 2.10 SG15 3.26 0.05 0.45 1.94 1.38 29.45 6.46 1.47 0.09 1.49 SG21 4.04 0.05 0.48 1.58 1.51 25.55 7.31 1.50 0.11 1.73 SG22 4.18 0.05 0.49 1.63 1.56 26.54 7.64 1.67 0.12 1.78 SG23 3.85 0.05 0.50 1.70 1.55 27.03 7.54 1.76 0.10 1.93 SG24 3.36 0.05 0.47 1.91 1.43 28.66 7.08 1.48 0.09 1.46 SG25 3.05 0.05 0.43 1.94 1.37 29.49 6.73 1.34 0.08 1.92 SG26 2.94 0.04 0.42 1.94 1.27 32.06 6.37 1.13 0.08 1.18 SG32 4.06 0.06 0.48 1.55 1.41 25.43 7.22 1.58 0.12 1.11 SG31 4.22 0.05 0.49 1.63 1.58 26.51 7.65 1.74 0.13 1.57 SG30 4.02 0.05 0.50 1.68 1.56 26.81 7.67 1.59 0.11 1.76 SG29 3.83 0.05 0.50 1.89 1.47 28.28 7.42 1.62 0.10 1.26 SG28 3.35 0.05 0.47 2.02 1.53 28.75 6.57 1.48 0.09 1.83 SG27 3.37 0.05 0.47 1.91 1.34 29.57 6.71 1.42 0.09 1.45 SG44 4.17 0.05 0.49 1.51 1.41 25.79 7.47 1.62 0.11 1.02 SG43 4.10 0.05 0.48 1.63 1.65 25.58 7.25 1.63 0.11 1.46 SG42 3.96 0.05 0.49 1.64 1.52 26.41 7.53 1.68 0.12 1.22 SG41 3.80 0.05 0.49 1.78 1.66 . 27.21 7.25 1.62 0.09 1.69 SG40 3.50 0.05 0.48 1.90 1.52 28.07 6.79 1.48 0.09 1.78 SG39 3.31 0.05 0.47 1.88 1.43 27.82 6.43 1.47 0.09 1.77 189 Sample Fe Mn Ti Ca K Si Al Mg P Na SG45 4.10 0.05 0.48 1.52 1.47 25.91 7.53 1.71 0.11 1.39 SG46 4.13 0.05 0.49 1.62 1.64 26.48 7.67 1.66 0.12 2.11 SG47 3.90 0.05 0.49 1.76 1.58 26.72 7.42 1.57 0.11 1.74 SG48 3.74 0.05 0.49 1.78 1.50 27.67 7.27 1.66 0.10 1.42 SG49 3.26 0.05 0.46 2.48 1.37 28.43 6.58 1.41 0.10 1.65 SG50 3.31 0.05 0.48 1.94 1.34 29.66 6.80 1.41 0.10 1.76 SGS1 4.09 0.06 0.46 1.53 1.52 25.73 7.52 1.62 0.12 1.26 SG52 4.15 0.07 0.46 1.52 1.48 25.85 7.51 1.53 0.13 1.62 SG53 4.21 0.08 0.45 1.49 1.34 25.40 7.50 1.55 0.12 1.42 SG54 4.08 1.42 0.41 1.18 1.11 23.56 6.92 1.58 0.13 0.95 SG55 4.22 0.79 0.42 1.24 1.27 23.51 6.44 1.81 0.12 2.50 SG56 4.28 0.38 0.43 1.25 1.18 24.52 7.25 1.76 0.11 1.31 SG57 4.29 0.16 0.46 1.31 1.38 25.35 7.65 1.75 0.13 1.70 SG58 4.38 0.34 0.45 1.29 1.18 25.31 7.37 1.85 0.13 -0.66 SG59 4.29 0.48 0.44 1.29 1.37 24.55 7.25 1.52 0.14 1.61 A O 3.76 0.05 0.52 1.89 1.45 30.26 7.35 1.55 0.11 1.85 KA1 3.14 0.05 0.51 1.95 1.26 31.60 5.92 1.41 0.08 1.79 KA2 3.23 0.05 0.51 1.86 1.10 32.99 5.37 1.28 0.07 1.73 W6 3.21 0.05 0.45 1.73 1.27 31.26 6.16 1.37 0.09 1.53 W7 3.52 0.07 0.63 2.21 0.95 32.30 5.41 1.35 0.07 1.79 W8 2.59 0.05 0.40 1.68 1.01 33.74 5.34 1.07 0.06 1.63 A12 3.11 0.06 0.37 1.98 0.95 32.79 5.65 1.19 0.07 1.76 190 Table A4.4 Minor and major element to aluminum ratios for surface samples from the Strait of Georgia. Values are multiplied by 10 4 except for Ag/Al , T i /A l , and P /Al which are multiplied by 1(A lfj3, and lfj3, respectively. Values are listed on a salt free basis. Sample Ag/Al plE+06) Pb/Al Zr/Al Y/Al Sr/Al Rb/Al Zn/Al Cu/AI Ni/Al Co/Al Mn/Al V/Al Cr/Al Ba/Al 5903 3.54 2.82 16.17 2.52 34.58 9.78 16.39 7.22 6.50 2.10 116 19.92 14.28 75.52 5904 2.89 3.34 19.20 2.50 40.71 8.54 15.09 5.51 5.96 2.20 175 20.11 14.21 76.84 5911 3.17 2.17 18.55 2.42 35.08 9.72 15.51 5.76 6.57 1.79 113 20.76 15.47 77.69 5912 2.87 2.29 16.65 2.14 38.96 9.63 14.82 6.09 6.43 2.39 215 19.58 14.60 77.75 VG1 2.84 0.00 18.70 2.10 38.51 10.93 13.69 7.21 6.78 1.33 131 21.81 16.90 83.34 VG2 3.98 2.01 17.91 2.61 33.28 9.31 15.03 5.53 6.07 2.00 92 19.06 14.69 71.52 VG3 3.12 1.88 18.91 3.12 33.93 10.35 14.06 4.90 6.04 2.03 99 19.00 15.56 73.75 VG4 3.02 2.07 18.08 3.48 36.07 9.87 15.54 5.44 6.25 2.42 137 19.98 14.92 75.81 VG5 2.71 2.19 15.19 2.32 37.78 9.09 16.15 6.22 6.41 2.40 508 20.08 13.72 73.47 SGI 2.44 1.87 19.91 3.14 37.66 8.41 14.57 5.25 5.46 1.92 96 19.81 14.10 71.86 SG2 2.41 1.95 16.88 2.58 36.02 7.95 14.71 5.36 6.66 1.93 256 19.89 14.68 70.59 SG3 2.47 2.20 16.76 2.75 37.61 9.91 15.90 5.69 5.95 2.24 296 21.89 15.36 71.43 SG4 2.60 2.34 17.49 2.73 38.19 10.16 16.38 5.52 7.12 2.76 258 24.69 16.52 82.84 SG5 3.38 2.26 16.73 2.80 34.83 8.93 15.63 6.12 6.77 2.12 155 23.01 15.08 76.71 SG6 2.56 2.07 16.44 2.06 35.03 9.66 15.07 5.65 6.63 1.99 141 22.58 15.47 80.05 SG7 2.95 2.10 18.38 3.17 37.77 8.69 15.83 6.22 7.29 2.51 169 20.88 15.65 73.31 SG8 2.94 2.05 20.53 3.04 37.95 9.37 15.29 5.92 6.39 2.33 99 22.68 17.17 83.07 SG9 3.21 1.92 20.26 3.12 37.88 8.23 15.09 5.90 6.78 1.86 100 22.08 18.50 84.71 SG10 3.82 1.87 19.26 2.96 35.82 9.64 14.73 6.43 6.92 2.47 94 22.01 17.30 83.64 SG11 4.07 2.12 20.12 2.88 35.35 9.87 14.54 5.77 6.94 2.31 92 22.05 17.38 84.98 SG12 4.81 1.76 21.07 2.62 35.96 9.72 15.24 6.13 7.19 2.09 88 20.32 17.68 86.31 SG13 3.94 1.64 26.51 2.52 42.14 9.33 14.48 5.98 7.05 2.45 98 20.53 18.97 94.29 SG14 2.60 1.21 25.43 3.72 40.41 8.09 13.71 5.03 7.59 2.42 102 20.51 20.70 94.80 SG20 3.35 1.91 19.67 2.80 35.53 9.38 15.07 6.13 7.10 2.07 89 22.73 17.08 85.06 SG19 4.51 1.89 19.96 2.98 36.13 10.43 14.89 6.47 7.14 1.54 98 22.94 18.18 89.85 SGI 8 5.76 1.88 20.56 3.61 35.22 8.76 14.84 6.41 7.05 2.13 84 21.86 17.22 88.53 SG17 7.20 1.72 22.88 2.83 36.92 8.92 14.35 6.50 7.50 2.13 92 22.53 19.92 91.47 SG16 6.66 1.82 27.34 2.93 40.52 8.72 13.51 5.86 7.52 2.67 93 22.84 20.74 97.02 SG15 4.47 1.58 26.36 3.47 43.83 7.89 13.84 5.61 7.10 2.47 96 23.32 23.68 101.62 SG21 3.61 1.87 19.21 2.98 35.15 8.73 15.25 6.75 6.43 2.10 89 22.27 16.69 83.92 SG22 5.58 1.72 18.74 3.11 33.23 8.9 14.74 6.55 7.16 2.21 86 22.45 16.62 85.88 SG23 9.86 1.96 20.68 2.55 34.97 9.45 15.53 6.89 6.64 2.30 83 21.07 18.27 87.52 SG24 10.20 2.11 24.36 3.14 39.31 8.19 14.06 6.43 6.56 1.92 82 20.36 19.56 88.24 SG25 7.38 1.75 22.50 2.68 40.65 7.69 13.31 5.60 5.72 1.93 85 20.25 18.24 90.04 SG26 4.21 1.44 23.91 3.21 43.09 7.73 12.36 4.74 6.28 2.02 89 21.03 20.45 92.31 SG32 3.97 2.00 18.90 2.76 36.96 9.63 15.23 6.01 6.59 2.22 109 24.10 17.45 85.71 SG31 5.88 1.89 18.67 3.30 34.10 10.05 14.59 6.44 6.96 2.59 90 22.87 17.21 86.10 SG30 11.10 2.04 20.21 2.78 34.82 9.87 14.89 7.14 6.62 2.47 85 22.57 17.40 85.59 SG29 10.40 2.09 22.94 2.66 35.73 8.29 14.22 6.59 6.72 2.23 85 22.88 20.94 89.59 SG28 8.45 1.67 26.55 3.29 40.97 7.97 14.00 5.35 6.34 2.49 92 23.90 23.95 97.15 SG27 6.11 1.68 26.09 3.28 41.14 8.4 12.63 4.80 6.32 2.43 91 22.87 22.48 95.68 SG44 3.75 2.98 18.74 2.76 33.91 9.5 15.84 5.95 7.08 2.01 89 21.69 16.83 83.52 SG43 6.04 2.23 20.38 3.01 35.07 8.52 16.28 6.97 7.62 1.98 87 21.77 17.63 86.27 SG42 8.06 2.08 20.31 2.84 35.45 9.26 15.25 7.48 6.95 2.29 85 20.85 17.47 84.81 SG41 8.75 2.84 22.68 3.28 36.35 9.05 14.60 6.96 7.01 2.04 88 23.56 19.29 90.83 SG40 8.35 1.88 26.26 3.07 41.15 9.49 13.80 6.45 7.39 1.90 87 23.05 21.01 95.30 SG39 6.20 1.83 27.62 3.39 42.79 7.57 14.82 6.82 7.08 2.36 96 24.17 21.71 100.61 191 Sample Ag/Al (*lE+06) Pb/Al Zr/Al Y/Al Sr/Al Rb/Al Zn/Al Cu/Al Ni/Al Co/Al Mn/Al V/Al Cr/Al Ba/Al SG45 3.70 2.07 17.75 2.56 34.60 10.64 15.38 6.40 7.43 1.68 94 23.03 16.59 84.54 SG46 5.92 1.93 19.28 2.61 32.81 9.48 14.90 6.44 7.08 1.76 89 21.77 16.81 89.18 SG47 9.25 2.00 20.95 3.86 35.93 9.53 15.35 6.83 7.05 1.94 87 23.09 18.32 90.46 SG48 8.66 1.90 22.63 2.99 37.09 7.85 14.10 7.36 7.29 2.62 84 22.22 19.92 92.68 SG49 8.27 1.80 25.47 3.16 41.60 8.22 14.10 6.37 6.56 2.11 92 23.73 21.79 93.99 SG50 6.32 1.66 28.12 3.47 41.00 6.86 12.43 5.41 7.00 2.02 89 22.62 20.53 92.81 SG51 3.39 2.61 17.16 2.87 35.33 9.12 15.22 6.38 6.69 2.46 94 22.79 16.32 84.39 SG52 3.49 2.69 16.41 2.67 34.85 9.38 15.59 6.90 6.79 1.83 117 22.39 15.39 79.70 SG53 2.51 2.77 16.63 2.55 39.24 10.37 16.05 6.65 6.33 2.37 141 21.99 14.49 79.90 SG54 2.03 3.01 13.47 3.33 48.15 11.84 20.33 7.46 7.40 2.90 2420 21.29 12.41 65.85 SG55 1.62 2.19 15.08 3.32 46.40 11.86 20.64 6.95 8.75 3.53 1472 26.59 14.65 85.33 SG56 1.78 3.37 13.24 3.20 41.04 9.86 21.68 7.60 7.57 3.92 694 22.40 13.26 72.66 SG57 1.82 2.71 14.57 3.12 35.92 10.02 17.64 6.68 7.26 2.42 288 21.44 14.58 79.84 SG58 2.17 2.46 14.86 3.04 36.31 9.87 16.38 5.95 7.40 2.50 572 23.60 14.39 76.63 SG59 1.96 2.66 14.78 2.37 39.69 9.74 17.74 6.41 7.11 2.54 858 24.47 14.37 80.00 A O 17.70 2.99 26.01 3.03 38.17 7.96 14.25 6.24 6.31 1.94 81 20.00 '20.56 89.94 KA1 5.43 2.17 38.40 3.20 47.56 7.29 14.13 4.36 7.40 6.13 104 22.83 27.68 100.14 KA2 1.80 0.00 41.93 3.50 50.49 5.18 13.19 2.56 6.60 8.04 125 24.51 30.83 100.05 W6 7.30 2.30 26.80 2.67 44.47 8.16 14.22 4.91 6.46 9.80 104 20.53 20.22 97.08 W7 0.91 2.62 39.72 4.29 50.87 6.25 12.12 2.60 6.92 10.02 140 24.13 35.30 98.56 W8 0.96 1.49 31.34 2.99 49.85 4.94 11.11 1.99 6.69 11.54 119 20.85 25.10 99.06 A12 1.16 2.83 14.09 3.13 44.79 5.16 10.72 2.17 4.83 20.64 114 18.49 16.08 89.36 192 Sample Fe/Al Ti/Al (*lE+03) Ca/Al K/Al Si/Al Mg/Al P/Al (*lE+03) Na/Al 5903 0.55 58.87 0.15 0.19 3.36 0.21 17.51 0.23 5904 0.51 59.84 0.18 0.19 3.69 0.19 16.42 0.27 5911 0.56 63.11 0.15 0.20 3.54 0.21 17.39 0.27 5912 0.55 60.16 0.16 0.18 3.54 0.20 20.95 0.26 VG1 0.54 63.38 0.16 0.18 3.43 0.23 17.38 0.23 VG2 0.55 64.28 0.17 0.18 3.48 0.21 16.01 0.19 VG3 0.54 65.51 0.17 0.17 3.57 0.21 16.32 0.20 VG4 0.57 64.37 0.17 0.19 3.52 0.20 19.00 0.28 VG5 0.56 60.63 0.15 0.17 3.38 0.21 19.19 0.17 SGI 0.52 65.86 0.19 0.19 3.66 0.20 15.77 0.28 SG2 0.55 61.13 0.15 0.17 3.46 0.21 16.84 0.23 SG3 0.57 64.80 0.15 0.17 3.51 0.22 18.74 0.21 SG4 0.61 64.67 0.15 0.20 3.60 0.21 18.83 0.20 SG5 0.56 61.71 0.15 0.17 3.41 0.21 15.82 0.10 SG6 0.57 62.42 0.17 0.18 3.40 0.21 17.94 0.23 SG7 0.57 66.67 0.16 0.16 3.57 0.22 19.02 0.20 SG8 0.54 69.34 0.19 0.19 3.69 0.20 15.53 0.24 SG9 0.54 67.40 0.17 0.18 3.62 0.22 16.14 0.19 SG10 0.53 66.62 0.13 0.19 3.53 0.21 16.37 0.25 SG11 0.55 66.77 0.16 0.20 3.56 0.21 14.96 0.23 SG12 0.53 66.17 0.17 0.21 3.60 0.21 15.44 0.21 SG13 0.52 68.73 0.22 0.20 4.15 0.22 13.34 0.20 SG14 0.52 69.17 0.21 0.23 4.30 0.22 12.09 0.22 SG20 0.54 65.82 0.17 0.19 3.47 0.19 16.18 0.20 SG19 0.57 67.33 0.18 0.20 3.50 0.21 16.34 0.19 SGI 8 0.55 65.55 0.17 0.20 3.47 0.22 13.90 0.23 SGI 7 0.53 67.68 0.19 0.20 3.80 0.22 14.35 0.16 SG16 0.52 70.84 0.25 0.22 4.29 0.21 14.07 0.31 SG15 0.50 70.31 0.25 0.21 4.56 0.23 13.84 0.23 SG21 0.55 65.09 0.16 0.21 3.49 0.20 15.17 0.24 SG22 0.55 64.72 0.17 0.20 3.47 0.22 15.10 0.23 SG23 0.51 66.33 0.17 0.21 3.59 0.23 13.89 0.26 SG24 0.48 66.16 0.23 0.20 4.05 0.21 13.31 0.21 SG25 0.45 63.88 0.24 0.20 4.38 0.20 11.96 0.29 SG26 0.46 65.81 0.25 0.20 5.03 0.18 12.87 0.18 SG32 0.56 66.41 0.18 0.19 3.52 0.22 16.76 0.15 SG31 0.55 64.48 0.18 0.21 3.46 0.23 16.85 0.21 SG30 0.52 64.93 0.17 0.20 3.50 0.21 14.36 0.23 SG29 0.52 67.95 0.20 0.20 3.81 0.22 12.83 0.17 SG28 0.51 72.25 0.25 0.23 4.38 0.22 12.98 0.28 SG27 0.50 70.50 0.24 0.20 4.40 0.21 14.00 0.22 SG44 0.56 65.37 0.16 0.19 3.45 0.22 14.84 0.14 SG43 0.57 66.16 0.17 0.23 3.53 0.22 15.85 0.20 SG42 0.53 65.39 0.16 0.20 3.51 0.22 15.87 0.16 SG41 0.52 67.63 0.20 0.23 3.75 0.22 13.09 0.23 SG40 0.52 71.13 0.22 0.22 4.13 0.22 13.94 0.26 SG39 0.52 73.72 0.25 0.22 4.33 0.23 13.94 0.27 193 Sample Fe/Al Ti/Al (*lE+03) Ca/Al K/Al Si/Al Mg/Al P/Al (*lE+03) Na/Al SG45 0.55 63.62 0.16 0.20 3.44 0.23 15.24 0.18 SG46 0.54 64.25 0.18 0.21 3.45 0.22 16.19 0.28 SG47 0.53 65.83 0.17 0.21 3.60 0.21 14.75 0.23 SG48 0.51 67.32 0.20 0.21 3.80 0.23 13.65 0.20 SG49 0.50 69.44 0.21 0.21 4.32 0.21 15.03 0.25 SG50 0.49 70.84 0.24 0.20 4.36 0.21 14.55 0.26 SG51 0.54 61.61 0.17 0.20 3.42 0.21 16.59 0.17 SG52 0.55 61.27 0.16 0.20 3.44 0.20 16.73 0.22 SG53 0.56 60.64 0.17 0.18 3.39 0.21 16.17 0.19 SG54 0.59 59.72 0.12 0.16 3.41 0.23 19.16 0.14 SG55 0.66 64.92 0.15 0.20 3.65 0.28 18.91 0.39 SG56 0.59 58.93 0.14 0.16 3.38 0.24 14.75 0.18 SG57 0.56 59.74 0.14 0.18 3.31 0.23 17.40 0.22 SG58 0.59 60.51 0.14 0.16 3.43 0.25 17.75 SG59 0.59 60.09 0.14 0.19 3.39 0.21 19.89 0.22 A O 0.51 70.99 0.23 0.20 4.12 0.21 15.63 0.25 KA1 0.53 86.73 0.27 0.21 5.34 0.24 14.12 0.30 KA2 0.60 94.19 0.33 0.20 6.14 0.24 12.25 0.32 W6 0.52 73.54 0.24 0.21 5.07 0.22 14.28 0.25 W7 0.65 116.82 0.40 0.18 5.97 0.25 12.96 0.33 W8 0.49 75.50 0.31 0.19 6.31 0.20 10.67 0.30 A12 0.55 66.18 0.35 0.17 5.81 0.21 13.21 0.31 194 Table A4.5 Ag, Pb, S^Corg, 8 1 5 N , Corg, Cinorg, total carbon, nitrogen and sulphur, C / N and CI in core samples from the Strait of Georgia. Values are on a salt free basis, except for chlorine and isotopes of carbon and nitrogen. Isotopes of carbon are relative to PDB and nitrogen to air. The detection for N was approximately 0.05% (<D.L.=less than detection limit). Core Ag (ppb) Pb(ppm) dl5N (0/00) dl3C(0/00) Corg (wt. %) Cinorg (wt %) Ntot (wt. % Ctot (wt. % Stot (wt. %) C/N CI (wt. %) 5903-1 0-1 273 21.81 6.64 -23.12 1.72 0.11 0.17 1.83 0.08 10.04 3.51 5903-2 1-2 257 32.00 6.35 -23.08 1.75 0.10 0.17 1.84 0.06 10.33 2.95 5903-3 2-3 306 6.48 -23.13 1.77 0.12 0.17 1.88 0.06 10.24 2.62 5903-4 3-4 269 23.00 6.54 -23.14 1.66 0.12 0.17 1.77 0.05 10.02 2.57 5903-5 4-5 272 6.50 -23.27 1.46 0.12 0.15 1.57 0.01 9.57 2.42 5903-6 5-6 273 23.00 6.17 -23.08 1.65 0.12 0.16 1.76 0.05 10.17 2.41 5903-7 6-7 272 6.55 -23.18 1.74 0.11 0.17 1.85 0.06 10.05 2.28 5903-8 7-8 267 31.00 5.68 . -23.29 1.80 0.11 0.18 1.91 0.05 9.91 2.03 5903-9 9-10 265 6.35 -23.19 1.80 0.11 0.19 1.91 0.09 9.62 2.08 5903-11 10-12 251 25.00 6.32 -23.32 1.65 0.11 0.16 1.76 0.12 10.20 2.02 5903-13 14-16 28.00 5.98 -23.39 1.80 0.12 0.19 1.92 0.11 9.32 1.93 5903-15 18-20 241 24.00 6.05 -23.33 1.50 0.18 0.15 1.67 0.15 9.90 2.03 5903-17 22-24 40.00 5.80 -23.38 1.54 0.13 0.15 1.67 0.25 10.35 1.88 5903-19 26-28 6.45 -23.34 1.57 0.11 0.15 1.68 0.13 10.37 2.06 5903-21 30-35 6.16 -23.28 1.50 0.12 0.15 1.63 0.13 10.35 1.81 5903-22 35-40 6.33 -23.20 1.44 0.11 0.14 1.56 0.16 10.32 2.04 5903-23 40-45 214 6.22 -23.13 1.42 0.12 0.14 1.54 0.19 10.04 1.97 5903-24 45-50 24.00 6.46 -22.97 1.39 0.12 0.14 1.52 0.23 9.84 1.63 VG10-1 223 4.48 -22.35 1.69 0.12 0.17 1.80 0.13 9.79 4.05 VG1 1-2 235 4.88 -22.64 1.63 0.12 0.17 1.75 0.10 9.85 3.33 VG1 2-3 238 4.70 -22.79 1.54 0.13 0.15 1.67 0.12 10.05 2.47 VG1 3-4 239 5.01 -22.73 1.56 0.13 0.16 1.69 0.11 9.76 2.16 VG1 4-5 233 4.94 -22.78 1.55 0.12 0.15 1.67 0.12 10.30 2.02 VG1 5-6 225 4.82 -22.78 1.60 0.12 0.16 1.72 0.12 10.17 2.03 VG1 6-7 236 4.23 -22.78 1.55 0.14 0.16 1.68 0.12 9.98 1.94 VG1 7-8 236 4.49 -22.88 1.56 0.13 0.16 1.69 0.12 10.04 1.91 VG1 8-9 227 4.49 -22.76 1.54 0.12 0.15 1.66 0.12 10.20 1.71 VG1 9-10 240 4.73 -22.86 1.52 0.12 0.14 1.64 0.14 10.49 1.60 VG1 10-12 1.47 0.14 0.14 1.60 0.12 10.53 1.62 VG1 12-14 235 4.18 -23.19 1.47 0.12 0.14 1.59 0.13 10.77 1.67 VG1 14-16 229 1.53 0.11 0.14 1.65 0.15 10.89 1.77 VG1 16-18 4.26 -23.3 1.53 0.13 0.14 1.66 0.14 10.65 1.82 VG1 18-20 1.57 0.14 0.15 1.71 0.16 10.49 1.54 VG1 20-22 224 4.69 -22.97 1.58 0.13 0.15 1.71 0.16 10.75 1.64 VG1 22-24 1.54 0.14 0.15 1.68 0.18 10.42 1.54 VG1 24-26 4.83 -22.95 1.51 0.14 0.14 1.66 0.17 10.47 1.59 VG1 26-28 230 1.46 0.14 0.14 1.60 0.19 10.66 1.71 VG1 28-30 4.46 -23.04 1.45 0.15 0.14 1.59 0.19 10.53 1.70 VG1 30-35 1.43 0.15 0.13 1.58 0.19 10.67 1.58 VG1 35-40 236 4.85 -23.12 1.43 0.14 0.14 1.57 0.17 10.54 1.67 VG1 40-45 1.36 0.13 0.13 1.49 0.19 10.80 1.50 VG1 45-50 4.83 -23.06 1.34 0.14 0.12 1.48 0.20 10.94 1.62 SG4 0-1 199 12.47 5.53 -21.84 1.63 0.10 0.19 1.74 0.09 8.40 4.45 SG4 1-2 191 14.38 5.93 -22.24 1.91 0.10 0.21 2.00 0.15 8.98 3.61 SG4 2-3 199 13.11 5.85 -22.37 1.90 0.09 0.21 1.99 0.12 8.95 3.00 195 Core Ag (ppb) Pb (ppm) dl5N (0/00) dl3C (0/00) Corg (wt. %) Cinorg (wt. %) Ntot (wt. %) ctot (wt. %; Stot (wt. %) C/N CI (wt. %] SG4 3-4 201 14.37 5.91 -22.16 1.90 0.10 0.21 2.00 0.13 8.98 2.83 SG4 4-5 188 15.93 5.40 -22.23 1.85 0.09 0.20 1.94 0.16 9.08 2.86 SG4 5-6 197 15.61 5.64 -22.49 1.78 0.09 0.19 1.88 0.13 9.57 2.70 SG4 6-7 223 22.50 6.18 -22.36 1.81 0.09 0.20 1.90 0.18 9.14 2.78 SG4 7-8 235 16.71 5.67 -22.41 1.87 0.07 0.20 1.95 0.19 9.37 2.90 SG4 8-9 187 18.29 5.52 -22.45 1.86 0.08 0.20 1.93 0.21 9.39 2.83 SG4 9-10 214 24.49 5.78 -22.6 1.79 0.09 0.19 1.89 0.20 9.22 2.79 SG4 10-12 1.79 0.08 0.19 1.86 0.20 9.51 2.72 SG4 12-14 5.79 -22.57 1.75 0.08 0.19 1.83 0.20 9.42 2.43 SG4 14-16 213 25.28 1.80 0.08 0.19 1.87 0.22 9.61 2.43 SG4 16-18 5.69 -22.67 1.71 0.09 0.18 1.80 0.22 9.43 2.54 SG4 18-20 207 26.60 1.71 0.09 0.18 1.80 0.23 9.29 2.57 SG4 20-22 203 25.16 6.10 -22.45 1.72 0.08 0.18 1.80 0.20 9.55 2.60 SG4 22-24 207 31.71 1.73 0.06 0.18 1.80 0.21 9.77 2.57 SG4 24-26 5.49 -22.49 1.67 0.08 0.17 1.75 0.21 9.70 2.45 SG4 26-28 253 27.65 1.65 0.08 0.17 1.73 0.22 9.74 2.33 SG4 28-30 5.56 -22.57 1.61 0.10 0.16 1.71 0.24 9.84 2.36 SG4 30-35 205 25.41 1.58 0.09 0.16 1.67 0.24 9.99 2.22 SG4 35-40 5.27 -22.65 1.66 0.10 0.17 1.76 0.25 9.94 2.14 SG4 40-45 204 25.69 5.21 -22.59 1.66 0.07 0.17 1.73 0.25 9.82 1.88 SG17 0-1 584 13.80 3.42 -23.25 1.34 0.11 0.12 1.45 0.11 11.27 2.07 SG17 1-2 582 14.20 3.39 -23.85 1.15 0.14 0.10 1.30 0.12 11.23 1.52 SGI 7 2-3 535 15.80 3.43 -23.77 1.13 0.15 0.10 1.28 0.14 11.28 1.41 SGI 7 3-4 529 15.70 3.51 -23.70 1.10 0.14 0.10 1.24 0.15 11.38 1.25 SG17 4-5 595 15.60 3.27 -23.82 1.06 O.n 0.09 1.22 0.14 11.16 1.19 SGI7 5-6 516 15.40 3.74 -23.70 1.06 0.16 0.09 1.22 0.14 11.14 1.13 SG17 6-7 582 15.30 3.55 -23.89 1.10 0.15 0.10 1.25 0.13 11.59 1.13 SG29 0-1 736 15.83 2.66 -23.32 1.31 0.12 0.11 1.43 0.15 11.56 1.78 SG29 1-2 695 16.75 3.25 -24.00 1.26 0.12 0.10 1.38 0.16 12.00 1.51 SG29 2-3 707 15.75 3.35 -23.85 1.26 0.11 0.11 1.37 0.18 11.53 1.35 SG29 3-4 705 15.79 3.33 -23.80 1.17 0.15 0.10 1.32 0.20 11.36 1.26 SG29 4-5 854 16.88 3.34 -23.80 1.21 0.11 0.10 1.32 0.21 12.13 1.22 SG29 5-6 703 16.64 3.41 -23.98 1.35 0.11 0.10 1.47 0.18 13.47 1.25 SG29 6-7 723 15.84 3.11 -23.91 1.20 0.13 0.10 1.33 0.17 11.71 1.26 SG42 0-1 697 15.67 3.87 -22.99 1.54 0.13 0.15 1.67 0.12 10.08 2.75 SG42 1-2 715 16.43 4.03 -23.39 1.47 0.13 0.14 1.61 0.14 10.62 2.05 SG42 2-3 681 17.15 3.82 -23.45 1.40 0.13 0.13 1.53 0.17 10.82 1.89 SG42 3-4 724 17.46 3.96 -23.54 1.46 0.11 0.14 1.57 0.17 10.07 1.81 SG42 4-5 642 17.20 4.11 -23.57 1.41 0.13 0.12 1.54 0.16 11.78 1.72 SG42 5-6 691 18.04 4.11 -23.50 1.31 0.14 0.12 1.45 0.17 11.09 1.37 SG42 6-7 618 17.41 3.96 -24.71 1.34 0.14 0.12 1.48 0.15 10.81 1.59 SG55 0-1 127 14.07 5.78 -21.95 2.06 0.08 0.24 2.14 0.15 8.72 3.71 SG55 1-2 134 6.13 -21.65 2.06 0.08 0.23 2.14 0.09 8.86 3.97 SG55 2-3 131 6.33 -21.65 2.03 0.06 0.23 2.09 0.10 9.00 3.80 SG55 3-4 144 6.34 -21.62 2.07 0.08 0.23 2.15 0.07 9.05 3.79 SG55 4-5 140 6.28 -20.55 1.96 0.08 0.22 2.04 0.07 8.88 3.49 SG55 5-6 121 5.96 -21.46 1.94 0.07 0.22 2.01 0.10 9.01 3.52 SG55 6-7 129 6.14 -21.62 1.92 0.07 0.21 1.99 0.12 9.04 3.42 SG55 7-8 134 6.04 -21.61 1.93 0.09 0.21 2.02 0.13 9.02 3.57 SG55 8-9 125 6.31 -21.72 1.89 0.14 0.21 2.03 0.13 8.80 3.37 196 Core Ag (ppb) Pb (ppm) dl5N (0/00) dl3C (0/00) Corg (wt. %) Cinorg (wt. %) Ntot (wt. %) ctot (wt. %; Stot (wt. %) C/N CI (wt. %: SG55 9-10 6.15 -21.9 1.91 0.09 0.22 2.00 0.13 8.86 3.25 SG55 10-12 141 1.87 0.09 0.21 1.96 0.16 8.83 3.08 SG55 12-14 5.47 -22.02 1.84 0.08 0.20 1.92 0.14 9.21 3.37 SG55 14-16 142 1.89 0.08 0.20 1.97 0.18 9.37 3.23 SG55 16-18 5.63 -21.92 1.95 0.06 0.20 2.01 0.14 9.85 3.26 SG55 18-20 122 1.82 0.08 0.20 1.90 0.20 9.21 3.22 SG55 20-22 6.15 -21.82 1.79 0.09 0.20 1.88 0.17 9.12 3.31 SG55 22-24 116 1.85 0.09 0.20 1.93 0.19 9.22 3.25 SG55 24-26 5.82 -21.8 1.86 0.07 0.20 1.93 0.24 9.19 3.32 SG55 26-28 108 1.81 0.08 0.20 1.89 0.22 9.15 3.25 SG55 28-33 5.84 -21.66 1.78 0.12 0.20 1.90 0.23 9.04 3.36 SG55 33-35 1.70 0.10 0.19 1.80 0.28 8.88 3.45 SG55 35-40 5.91 -21.72 1.62 0.09 0.19 1.71 0.21 8.76 3.37 SG55 40-45 98 1.58 0.09 0.19 1.67 0.25 8.32 3.13 SG55 45-50 5.43 -21.14 1.57 0.08 0.19 1.65 0.30 8.38 3.09 SG55 50-55 1.51 0.08 0.19 1.60 0.31 8.11 3.03 SG55 55-60 92 6.19 -21.08 1.45 0.08 0.17 1.54 0.31 8.33 3.08 SG55 60-65 1.53 0.10 0.18 1.63 0.42 8.35 3.07 A12 0-1 65 8.84 2.68 -22.18 0.20 0.01 <D.L. 0.21 0.02 0.29 A12 1-2 60 9.85 0.37 0.01 <D.L. 0.38 0.05 0.26 A12 2-3 53 8.12 0.33 0.01 <D.L. 0.34 0.04 0.25 A12 3-4 71 10.65 0.25 0.02 <D.L. 0.26 0.05 0.26 A12 4-5 63 8.72 0.36 0.02 <D.L. 0.39 0.09 0.23 A12 5-6 86 10.56 0.41 0.02 <D.L. 0.43 0.08 0.26 A12 6-7 77 9.58 0.33 0.02 <D.L. 0.35 0.10 0.27 A12 7-8 89 10.46 0.20 0.03 <D.L. 0.24 0.03 0.26 A12 8-9 117 10.33 0.21 0.08 <D.L. 0.30 0.06 0.29 A12 9-10 65 8.91 0.24 0.01 <D.L. 0.25 0.03 0.29 A12 10-12 104 10.55 0.38 0.03 <D.L. 0.42 0.11 0.36 A12 12-14 88 9.45 0.22 0.03 <D.L. 0.25 0.04 0.33 A12 14-16 81 8.61 0.28 0.03 <D.L. 0.31 0.07 0.30 A12 16-18 87 0.21 0.03 <D.L. 0.24 0.04 0.30 A12 18-20 57 8.72 0.13 0.10 <D.L. 0.23 0.04 0.29 A12 20-22 80 0.20 0.02 <D.L. 0.22 0.05 0.31 A12 22-24 56 0.20 0.03 <D.L. 0.23 0.08 0.32 AO 0-1 1303 21.96 3.79 -22.81 1.59 0.06 <D.L. 1.64 0.36 0.66 AO 1-2 2185 31.12 3.35 -23.84 1.46 0.05 <D.L. 1.51 0.80 0.44 AO 2-3 3101 43.50 3.13 -24.32 1.05 0.02 <D.L. 1.08 0.85 0.36 AO 3-4 3325 59.84 2.80 -24.65 1.18 0.01 <D.L. 1.19 1.22 0.40 AO 4-5 2207 30.75 2.63 -24.23 0.84 0.02 0.07 0.86 1.00 13.91 0.40 AO 5-6 1272 19.25 3.02 -24.50 0.66 0.07 <D.L. 0.73 0.94 0.35 AO 6-7 1039 18.26 2.64 -24.28 0.67 0.13 <D.L. 0.80 1.26 0.36 AO 7-8 766 15.76 3.18 -24.09 0.34 0.05 <D.L. 0.38 0.64 0.30 AO 8-9 608 13.85 2.98 -24.60 0.50 0.05 <D.L. 0.55 0.80 0.33 AO 9-10 579 15.43 2.94 -24.74 0.74 0.08 <D.L. 0.82 1.08 0.39 AO 10-12 2.41 -24.98 1.03 0.06 <D.L. 1.09 1.26 0.38 AO 12-14 185 11.90 2.81 -24.95 2.21 0.04 <D.L. 2.26 1.18 0.42 AO 14-16 3.28 -24.73 1.48 0.06 <D.L. 1.54 0.89 0.57 AO 16-18 260 17.66 3.86 -24.63 1.24 0.06 <D.L. 1.30 0.76 0.86 AO 18-20 3.65 -24.39 0.39 0.03 <D.L. 0.42 0.31 0.49 AO 20-22 69 0.16 0.01 <D.L. 0.18 0.13 0.36 AO 22-24 2.04 -23.96 0.14 0.00 <D.L. 0.15 0.06 0.34 197 Core Ag (ppb) Pb (ppm) dl5N (0/00) dl3C (0/00) Corg (wt. %) Cinorg (wt. %) Ntot (wt. %) Ctot (wt. %) Stot (wt. %) C/N CI (wt. %) AO 24-26 56 7.99 0.12 0.00 <D.L. 0.13 0.05 0.33 AO 26-28 2.21 -23.57 0.17 0.00 <D.L. 0.17 0.07 0.33 AO 28-30 53 0.16 0.00 <D.L. 0.17 0.06 0.31 AO 30-32 2.12 -23.57 0.16 0.00 <D.L. 0.16 0.05 0.35 AG17 0-1 698 12.38 3.04 -23.96 1.30 0.09 0.11 1.39 0.15 12.22 1.83 AG17 1-2 669 16.27 3.22 -24.14 1.26 0.09 0.10 1.35 0.16 12.99 1.51 AG17 2-3 669 15.79 3.84 -24.17 1.21 0.07 0.10 1.28 0.16 12.59 1.43 A G 17 3-4 648 10.59 3.76 -24.21 1.23 0.08 0.10 1.31 0.19 12.54 1.39 AG17 4-5 779 15.52 2.60 -24.13 1.16 0.18 0.10 1.34 0.18 11.73 1.35 AG17 5-6 660 16.31 2.95 -23.58 1.57 0.09 0.18 1.66 0.18 8.80 1.23 AG17 6-7 593 10.47 3.85 -24.17 1.20 0.11 0.10 1.31 0.19 12.46 1.05 AG17 7-8 584 19.25 3.77 -24.17 1.22 0.07 0.10 1.29 0.18 12.49 1.21 A G 17 8-9 446 19.95 4.14 -24.14 1.26 0.08 0.10 1.34 0.24 13.07 1.26 AG17 9-10 396 12.37 4.19 -24.52 1.17 0.09 0.10 1.26 0.16 11.90 1.29 AG17 10-12 381 18.35 3.66 -24.02 1.16 0.08 0.09 1.24 0.17 13.08 1.21 AG17 12-14 369 21.33 4.71 -24.05 1.15 0.08 0.09 1.24 0.18 12.99 1.29 AG17 14-16 322 15.71 4.00 -24.06 1.14 0.09 0.09 1.22 0.17 12.52 1.23 AG17 16-18 322 20.20 4.47 -24.05 1.14 0.09 0.09 1.23 0.18 13.09 1.34 A G 17 18-20 320 19.40 4.73 -24.14 1.09 0.09 0.08 1.18 0.19 12.80 1.30 A G 17 20-22 314 13.41 4.96 -24.20 1.07 0.08 0.08 1.15 0.20 13.31 1.15 A G 17 22-24 302 19.74 3.87 -24.20 0.98 0.09 0.07 1.07 0.18 13.63 1.17 AG17 24-26 432 18.77 4.15 -24.10 1.02 0.07 0.08 1.09 0.18 12.89 1.24 AG17 26-28 331 12.71 4.72 -24.15 1.01 0.08 0.08 1.09 0.20 12.63 1.16 AG17 28-31 340 7.50 3.89 -24.25 0.98 0.08 0.08 1.06 0.18 12.61 1.16 AG54 0-1 391 17.66 5.51 -23.07 1.75 0.10 0.17 1.86 0.11 10.27 4.12 AG54 1-2 458 27.47 5.54 -23.21 1.85 0.10 0.16 1.96 0.11 11.26 3.08 AG54 2-3 433 19.14 5.15 -23.35 1.74 0.11 0.15 1.85 0.15 11.24 2.52 AG54 3-4 429 19.06 5.48 -23.27 1.63 0.11 0.15 1.74 0.15 10.98 2.31 AG54 4-5 428 19.19 5.29 -23.32 1.62 0.10 0.15 1.73 0.12 10.81 2.19 AG54 5-6 429 20.87 4.99 -23.20 1.58 0.10 0.14 1.68 0.14 10.91 1.77 AG54 6-7 496 19.80 5.80 -23.22 1.56 0.10 0.14 1.66 0.14 10.81 2.06 AG54 7-8 484 24.50 5.44 -23.21 1.56 0.11 0.14 1.66 0.13 11.19 1.96 AG54 8-9 443 24.19 5.77 -23.17 1.54 0.10 0.14 1.64 0.14 10.68 1.91 AG54 9-10 446 25.18 4.89 -23.34 1.53 0.10 0.14 1.63 0.15 11.12 1.86 AG54 10-12 346 32.55 5.69 -23.22 1.56 0.10 0.14 1.66 0.15 11.28 1.83 AG54 12-14 319 32.45 5.51 -23.30 1.53 0.10 0.14 1.64 0.19 11.03 1.88 AG54 14-16 332 19.09 4.52 -23.49 1.63 0.13 0.13 1.76 0.18 12.43 1.95 AG54 16-18 327 31.96 4.82 -23.32 1.47 0.12 0.13 1.59 0.19 11.25 1.92 AG54 18-20 331 32.51 5.18 -23.41 1.47 0.12 0.13 1.59 0.20 10.97 1.96 AG54 20-22 326 23.15 5.06 -23.45 1.41 0.12 0.12 1.53 0.22 11.47 2.03 AG54 22-24 328 33.79 5.56 -23.57 1.11 0.12 0.10 1.23 0.18 10.83 1.82 AG54 24-26 324 37.04 5.58 -23.54 1.41 0.13 0.12 1.54 0.22 11.65 1.81 AG54 26-28 340 34.39 5.82 -23.64 1.39 0.13 0.12 1.52 0.26 11.17 1.68 AG54 28-30 347 31.96 5.32 -23.62 1.36 0.13 0.12 1.49 0.25 11.81 1.67 AG54 30-35 346 31.01 5.46 -23.46 1.28 0.12 0.11 1.40 0.23 11.33 1.82 AG54 35-40 338 31.23 6.32 -23.40 1.32 0.12 0.12 1.45 0.26 11.25 1.80 AG54 40-45 272 29.13 6.11 -23.39 1.27 0.12 0.12 1.39 0.23 10.60 1.73 AG54 45-50 217 25.50 6.17 -23.21 1.23 0.11 0.11 1.34 0.22 10.99 1.79 AG54 50-55 216 23.39 6.02 -23.08 1.29 0.12 0.11 1.41 0.24 11.61 1.81 AG54 55-60 184 24.46 6.18 -23.07 1.17 0.12 0.11 1.29 0.24 10.42 1.58 AG54 60-65 164 23.59 6.72 -23.54 1.15 0.11 0.11 1.26 0.24 10.44 1.87 198 Core Ag (ppb) Pb(ppm) dl5N(0/00) dl3C (0/00) Corg (wt. %) Cinorg (wt. %) Ntot (wt. %) Ctot (wt. %) Stot (wt. %) C/N CI (wt. %) BPt-1 0-1 79 10.76 4.62 -22.98 0.72 0.13 <D.L. 0.85 0.08 0.66 BPt-1 3-4 78 9.47 4.22 -22.50 0.59 0.11 <D.L. 0.70 0.06 0.55 BPt-1 14-16 96 10.23 3.00 -24.05 0.77 0.13 <D.L. 0.91 0.15 0.54 BPt-1 31-36 91 8.82 1.94 -23.73 0.32 0.11 <D.L. 0.42 0.09 0.49 A10 0-1 55 9.52 4.42 -20.88 0.26 0.00 <D.L. 0.26 0.02 0.33 A10 3-4 58 10.02 5.02 -21.09 0.20 0.02 <D.L. 0.22 0.02 0.31 A10 14-16 136 13.28 4.53 -22.37 0.22 0.00 <D.L. 0.22 " 0.08 0.29 A10 26-31 45 8.23 2.53 -23.75 0.12 0.01 <D.L. 0.13 0.06 0.35 AO 0-1 888 19.30 4.23 -22.91 1.01 0.08 0.09 1.09 0.19 10.74 0.66 AO 3-4 1739 35.38 3.78 -24.14 1.04 0.06 0.08 1.10 0.39 12.52 0.45 AO 14-16 506 10.40 3.50 -24.40 0.41 0.04 <D.L. 0.45 0.55 0.40 AO 26-31 70 7.01 3.97 -23.84 0.13 0.05 <D.L. 0.18 0.06 0.36 199 Table A4.6 Minor element data and I/Corg ratios for core samples from the Strait of Georgia. Values are on a salt free basis and in units of ppm. Cores 5903, A G 17 and AG54 were not analyzed. Note that iodine values less than 10 ppm are unreliable. Core Zr Y Sr Rb Pb Zn Cu Ni Co Mn V Cr Ba I I/Corg (*lE+04) Mo VG10-1 147 17 303 86 39 108 57 53 1C 1.028 171 133 655 92 54 <D.L. VG1 1-2 145 18 260 85 11 114 47 52 14 697 165 130 628 92 56 <D.L. VG1 2-3 147 21 264 77 21 115 43 51 17 661 168 132 646 83 54 <D.L. VG1 3-4 142 21 263 71 19 114 44 51 16 657 175 132 635 77 49 <D.L. VG1 4-5 147 20 256 76 8 116 43 51 17 655 170 133 657 78 50 <D.L. VG1 5-6 145 23 261 71 16 111 46 51 17 642 169 130 634 83 52 <D.L. VG1 6-7 149 21 258 72 17 113 44 55 19 647 166 130 635 83 54 <D.L. VG1 7-8 150 22 260 78 7 116 45 53 14 619 165 126 614 86 55 <D.L. VG1 8-9 144 24 260 74 14 109 38 54 16 644 175 129 635 69 45 < D . L VG1 9-10 148 22 255 72 7 113 48 54 18 643 172 129 646 71 47 <D.L. VG1 10-12 147 26 251 71 26 115 45 57 16 648 170 130 624 62 42 <D.L. VG1 12-14 143 19 262 70 8 117 47 55 17 649 171 131 658 59 40 <D.L. VG1 14-16 148 20 247 69 17 116 47 54 18 663 174 136 646 60 39 <D.L. VG1 16-18 147 22 245 72 10 116 42 52 17 648 171 127 663 64 42 <D.L. VG1 18-20 153 24 243 69 17 115 40 51 14 622 164 126 621 69 44 <D.L. VG1 20-22 149 19 241 68 17 111 43 51 16 627 167 130 641 66 42 <D.L. VG1 22-24 152 22 243 69 23 112 44 50 14 641 171 135 663 66 43 <D.L. VG1 24-26 153 21 246 76 13 114 48 52 17 643 172 135 664 59 39 <D.L. VG1 26-28 144 26 246 65 11 117 43 51 16 632 169 129 652 54 37 <D.L. VG1 28-30 151 18 245 72 21 114 47 51 17 668 176 134 676 56 38 <D.L. VG1 30-35 154 25 248 73 20 112 44 53 17 652 168 135 664 58 41 <D.L. VG1 35-40 148 22 240 75 9 118 49 53 18 658 172 137 660 54 38 <D.L. VG1 40-45 153 20 243 77 18 118 46 55 13 660 175 135 670 49 36 <D.L. SG4 0-1 124 19 270 72 15 116 39 50 19 1,821 174 117 585 127 78 <D.L. SG4 1-2 128 19 255 64 21 123 44 52 13 954 169 113 568 124 65 <D.L. SG4 2-3 126 19 259 67 16 121 42 55 13 925 172 119 580 119 63 <D.L. SG4 3-4 123 21 255 76 14 124 43 52 15 883 169 117 588 113 59 <D.L. SG4 4-5 129 19 250 71 18 124 49 52 19 836 164 112 583 105 57 <D.L. SG4 5-6 126 19 242 67 16 127 48 48 16 825 170 118 590 96 54 <D.L. SG4 6-7 132 23 242 67 16 122 45 49 16 771 162 116 547 92 51 <D.L. SG4 7-8 132 18 239 72 17 125 48 51 15 775 162 115 578 97 51 <D.L. SG4 8-9 129 20 242 72 13 124 46 49 17 767 166 116 591 90 48 <D.L. SG4 9-10 126 17 245 69 22 123 44 50 21 724 161 116 576 88 49 <D.L. SG4 10-12 130 22 239 67 19 122 43 50 16 749 164 120 595 79 44 <D.L. SG4 12-14 131 22 244 65 21 121 44 50 17 729 161 115 584 77 44 <D.L. SG4 14-16 133 18 238 74 22 124 45 48 19 741 159 117 551 75 42 <D.L. SG4 16-18 128 20 234 75 24 128 46 54 21 762 166 117 582 76 44 <D.L. SG4 18-20 128 21 238 77 27 129 49 54 19 770 162 115 591 75 44 <D.L. SG4 20-22 132 22 241 85 22 136 46 55 17 740 161 114 580 81 47 <D.L. SG4 22-24 130 19 233 81 15 132 49 55 16 753 164 117 590 72 41 <D.L. SG4 24-26 129 20 236 75 25 136 44 59 19 775 173 119 621 73 44 <D.L. SG4 26-28 131 20 227 72 27 135 48 55 18 766 164 116 599 61 37 <D.L. SG4 28-30 128 27 238 73 26 138 47 61 14 785 165 116 601 65 40 <D.L. SG4 30-35 134 19 237 78 27 132 45 55 19 804 166 116 612 65 41 <D.L. SG4 35-40 135 25 238 63 19 132 45 56 18 847 164 116 600 62 37 <D.L. SG4 40-45 128 26 242 69 16 133 48 54 19 1,034 173 121 626 67 41 <D.L. 200 Core Zr Y Sr Rb Pb Zn Cu Ni Co Mn V Cr Ba I I/Corg (*lE+04) Mo SG17 0-1 166 21 268 65 9 104 47 55 16 671 164 145 665 24 18 <D.L. SG17 1-2 165 21 264 69 11 105 49 55 19 602 148 136 640 27 23 <D.L. SG17 2-3 173 27 261 74 17 114 47 53 17 621 156 138 668 26 23 <D.L. SG17 3-4 164 25 260 79 18 113 48 55 15 618 153 140 659 21 19 <D.L. SGI 7 4-5 165 23 258 70 13 112 45 54 17 632 158 136 685 20 19 <D.L. SGI7 5-6 162 22 254 61 7 111 47 55 18 613 156 134 668 22 21 <D.L. SG17 6-7 167 23 258 70 18 109 47 56 14 586 147 129 650 22 20 4 SG29 0-1 169 20 265 61 14 105 49 50 16 630 169 155 662 31 24 <D.L. SG29 1-2 171 20 268 73 18 113 57 51 16 596 149 135 630 26 20 <D.L. SG29 2-3 175 21 262 76 16 117 57 53 17 616 156 140 663 27 22 <D.L. SG29 3-4 168 23 253 67 12 113 53 57 17 600 157 136 672 21 18 <D.L. SG29 4-5 169 21 257 72 11 113 51 56 17 607 154 137 668 22 18 <D.L. SG29 5-6 174 22 259 68 17 113 52 50 22 611 155 137 661 25 18 <D.L. SG29 6-7 175 24 255 74 14 111 52 55 16 595 151 135 638 24 20 <D.L. SG42 0-1 153 21 267 70 15 115 56 52 17 640 157 131 638 60 39 <D.L. SG42 1-2 151 22 258 75 14 117 53 52 15 621 160 129 644 47 32 <D.L. SG42 2-3 148 24 254 73 6 122 55 56 16 624 158 132 664 35 25 <D.L. SG42 3-4 153 21 253 77 11 119 53 59 16 613 158 129 664 36 25 <D.L. SG42 4-5 155 29 247 75 23 118 50 57 17 608 155 130 650 37 26 <D.L. SG42 5-6 150 29 256 75 13 120 53 57 18 621 161 131 664 34 26 <D.L. SG42 6-7 149 25 257 73 20 119 54 56 18 627 163 130 655 33 25 <D.L. SG55 0-1 97 21 299 76 19 133 45 56 23 9,475 171 94 549 189 92 <D.L. SG55 1-2 105 20 276 76 30 135 52 56 23 5,137 196 109 609 172 83 <D.L. SG55 2-3 110 20 249 65 17 140 49 52 21 4,030 188 106 575 152 75 <D.L. SG55 3-4 109 18 274 75 25 143 49 53 19 4,842 191 108 574 146 70 <D.L. SG55 4-5 105 22 256 74 18 139 46 53 23 5,254 196 111 600 137 70 <D.L. SG55 5-6 105 16 251 72 27 145 51 54 21 5,103 193 109 606 138 71 <D.L. SG55 6-7 111 13 242 76 12 146 51 57 20 4,775 190 108 587 120 62 <D.L. SG55 7-8 105 23 249 68 18 152 52 55 23 5,735 183 108 578 120 62 3 SG55 8-9 109 20 238 77 19 149 54 55 22 5,917 186 105 572 127 67 <D.L. SG55 9-10 108 22 236 74 24 153 51 59 22 5,370 187 107 569 121 63 <D.L. SG55 10-12 108 19 242 74 20 153 50 57 23 4,234 185 108 576 115 62 <D.L. SG55 12-14 111 22 244 71 28 157 54 60 22 4,247 192 112 603 111 60 <D.L. SG55 14-16 110 17 240 69 28 156 54 55 24 3,994 186 108 598 106 56 <D.L. SG55 16-18 110 22 242 80 18 148 54 57 23 3,926 199 116 633 102 53 <D.L. SG55 18-20 109 21 243 79 32 145 53 56 23 4,158 187 110 609 105 58 <D.L. SG55 20-22 108 23 241 78 21 149 51 52 24 4,448 186 106 566 103 57 <D.L. SG55 22-24 110 19 240 73 25 146 50 56 25 4,427 192 107 614 105 57 3 SG55 24-26 109 18 236 69 29 144 53 55 26 4,326 183 108 597 103 55 <D.L. SG55 26-28 107 22 236 86 21 139 53 54 22 4,773 194 114 622 100 55 5 SG55 28-33 106 19 242 82 18 136 53 52 23 6,008 186 107 589 95 53 <D.L. SG55 33-35 110 20 235 80 16 134 50 56 22 4,390 180 106 616 97 57 5 SG55 35-40 107 19 241 83 17 129 51 56 23 3,830 179 102 590 110 68 <D.L. SG55 40-45 110 21 237 79 22 124 48 55 24 3,689 187 107 613 102 64 <D.L. SG55 45-50 108 19 244 78 10 117 46 56 21 3,559 188 105 592 102 65 <D.L. SG55 50-55 112 . 20 241 79 11 115 48 56 25 3,391 187 103 589 88 58 <D.L. SG55 55-60 107 21 240 75 15 114 40 59 22 3,873 185 103 601 98 67 <D.L. SG55 60-65 111 22 235 71 12 120 45 56 21 4,102 187 109 613 93 61 5 201 Core Zr Y Sr Rb Pb Zn Cu Ni Co Mn V Cr Ba I I/Corg (*lE+04) Mo A12 0-1 80 18 253 29 16 61 12 27 117 644 104 91 504 9 44 <D.L. A12 1-2 95 20 257 29 3 64 13 35 48 668 115 116 501 7 20 4 A12 2-3 92 15 257 30 4 61 7 28 132 595 102 96 516 0 0 <D.L. A12 3-4 123 17 256 32 2 66 13 31 120 576 107 104 513 3 14 <D.L. A12 4-5 110 18 259 35 1 67 11 31 68 560 108 106 553 3 9 <D.L. A12 5-6 112 14 264 33 17 64 13 32 52 542 108 105 551 3 8 <D.L. A12 6-7 113 16 256 36 13 60 10 27 101 550 109 107 530 6 19 <D.L. A12 7-8 114 16 260 33 12 68 13 34 95 524 105 100 521 2 10 <D.L. A12 8-9 122 14 270 41 10 70 16 29 137 543 111 101 545 7 31 <D.L. A12 9-10 108 13 260 28 10 62 14 30 111 494 100 87 518 5 19 <D.L. A12 10-12 130 17 262 47 3 74 21 39 112 544 114 106 583 7 18 <D.L. A12 12-14 141 18 262 40 15 69 17 35 114 525 106 106 554 7 33 <D.L. A12 14-16 130 15 265 33 12 68 23 36 81 541 111 107 563 2 8 <D.L. A12 16-18 120 13 252 36 18 63 20 33 71 550 111 107 546 6 29 <D.L. A12 18-20 111 17 270 40 7 58 15 32 109 563 104 98 529 5 39 <D.L. A12 20-22 125 16 258 36 6 64 17 38 86 586 112 112 586 5 26 <D.L. A12 22-24 142 20 256 32 3 58 23 31 138 594 112 124 572 7 33 <D.L. AO 0-1 191 22 281 58 23 105 46 46 14 597 147 151 661 11 7 <D.L. AO 1-2 187 20 270 57 36 120 61 49 17 560 145 159 639 9 6 <D.L. AO 2-3 176 19 262 67 29 129 71 54 15 597 151 154 670 7 7 <D.L. AO 3-4 173 21 273 54 34 129 63 50 15 569 144 161 663 8 7 <D.L. AO 4-5 171 14 273 56 36 120 56 46 13 576 145 172 645 5 6 <D.L. AO 5-6 165 20 277 53 25 106 47 53 16 613 151 157 643 3 5 <D.L. AO 6-7 175 18 266 55 18 101 36 49 15 600 148 153 629 4 5 <D.L. AO 7-8 160 20 270 49 18 93 34 45 17 580 142 153 615 6 18 <D.L. AO 8-9 171 21 271 53 23 97 34 49 16 605 148 159 640 6 13 <D.L. AO 9-10 166 19 270 48 19 96 34 46 16 612 148 152 615 9 12 <D.L. AO 10-12 164 20 280 49 15 84 31 42 18 583 135 160 623 4 4 <D.L. AO 12-14 151 18 273 52 4 82 28 44 15 543 131 151 613 7 3 <D.L. AO 14-16 161 21 261 61 10 100 41 51 18 599 144 139 651 10 7 <D.L. AO 16-18 152 21 249 73 27 133 60 70 22 668 171 139 693 13 10 <D.L. AO 18-20 144 15 269 41 9 74 24 38 12 537 127 130 606 0 0 <D.L. AO 20-22 150 17 270 35 10 59 33 35 52 472 102 111 555 5 29 <D.L. AO 22-24 166 18 269 36 12 60 25 33 63 463 104 116 559 3 23 <D.L. AO 24-26 156 13 262 44 5 59 14 32 61 451 102 109 543 6 47 <D.L. AO 26-28 144 19 259 35 -2 57 14 34 37 474 107 124 580 2 13 <D.L. AO 28-30 152 18 270 34 11 59 12 34 46 481 105 120 562 2 12 <D.L. AO 30-32 155 19 271 39 4 58 12 35 38 477 109 126 560 5 34 <D.L. 202 Table A4.7 Major element data for core samples from the Strait of Georgia. Values are on a salt free basis and in units of weight percent. Cores 5903 and VG1 were not analyzed. Core Fe Mn Ti Ca K Si Al Mg P Na SG4 0-1 4.34 0.13 0.46 1.38 1.40 25.43 7.06 1.46 0.13 1.43 SG4 1-2 4.50 0.07 0.48 1.40 1.40 26.56 7.49 1.78 0.12 1.53 SG4 2-3 4.30 0.07 0.46 1.41 1.56 25.84 7.06 1.68 0.12 2.04 SG4 3-4 4.53 0.07 0.49 1.40 1.44 26.29 7.37 1.67 0.10 1.12 SG4 4-5 4.33 0.07 0.47 1.40 1.53 26.13 7.36 1.80 0.11 1.20 SG4 5-6 4.42 0.07 0.47 1.44 1.67 26.39 7.38 1.76 0.11 2.11 SG4 6-7 4.37 0.07 0.48 1.44 1.66 26.52 7.36 1.63 0.10 1.78 SG4 7-8 4.25 0.06 0.48 1.41 1.53 26.01 7.21 1.60 0.09 1.92 SG4 8-9 4.36 0.07 0.48 1.47 1.60 26.47 7.26 1.61 0.10 1.84 SG4 9-10 4.24 0.06 0.47 1.40 1.56 25.89 7.24 1.48 0.09 1.48 SG4 10-12 4.41 0.06 0.49 1.47 1.69 26.61 7.42 1.57 0.10 1.99 SG4 12-14 4.33 0.06 0.48 1.49 1.63 26.42 7.37 1.63 0.09 1.88 SG4 14-16 4.24 0.06 0.48 1.50 1.58 26.41 7.31 1.56 0.09 1.85 SG4 16-18 4.28 0.06 0.48 1.45 1.70 26.71 7.47 1.69 0.10 1.84 SG4 18-20 4.29 0.06 0.47 1.40 1.56 26.15 7.25 1.61 0.10 1.54 SG4 20-22 4.30 0.06 0.48 1.40 1.58 26.57 7.43 1.68 0.09 1.67 SG4 22-24 4.31 0.06 0.48 1.38 1.51 26.10 7.22 1.59 0.09 1.63 SG4 24-26 4.40 0.06 0.48 1.40 1.62 26.69 7.32 1.66 0.10 1.81 SG4 26-28 4.40 0.06 0.49 1.45 1.78 27.22 7.43 1.70 0.10 2.17 SG4 28-30 4.61 0.06 0.49 1.46 1.65 27.60 7.71 1.79 0.10 1.70 SG4 30-35 4.24 0.06 0.49 1.42 1.48 26.13 7.20 1.69 0.09 1.57 SG4 35-40 4.28 0.06 0.48 1.47 1.62 26.37 7.16 1.54 0.09 1.62 SG4 40-45 4.40 0.08 0.49 1.46 1.56 26.59 7.31 1.70 0.10 1.44 SG170-1 3.85 0.05 0.49 1.77 1.42 27.60 7.27 1.61 0.10 1.14 SG17 1-2 3.91 0.05 0.50 1.75 1.55 28.30 7.17 1.66 0.09 1.76 SG17 2-3 3.80 0.05 0.50 1.80 1.73 28.00 7.01 1.53 0.09 1.53 SGI7 3-4 3.84 0.05 0.50 1.76 1.67 27.80 7.08 1.62 0.10 1.81 SGI 7 4-5 4.02 0.05 0.49 1.75 1.72 27.90 7.06 1.67 0.09 1.64 SG17 5-6 3.79 0.05 0.48 1.74 1.72 27.80 6.93 1.75 0.09 1.79 SGI 7 6-7 3.74 0.05 0.49 1.77 1.73 28.00 6.87 1.62 0.10 1.67 SG290-1 3.81 0.05 0.50 1.89 1.46 28.13 7.38 1.63 0.09 1.42 SG29 1-2 3.78 0.05 0.49 1.82 1.74 27.61 6.75 1.66 0.09 1.81 SG29 2-3 3.84 0.05 0.49 1.83 1.78 27.28 6.76 1.64 0.09 1.75 SG29 3-4 3.87 0.05 0.50 1.79 1.58 27.37 7.00 1.68 0.10 1.69 SG294-5 3.86 0.05 0.50 1.77 1.67 27.56 6.99 1.67 0.09 1.66 SG29 5-6 3.81 0.05 0.50 1.75 1.64 27.45 6.81 1.64 0.09 1.48 SG29 6-7 3.77 0.05 0.50 1.75 1.61 27.45 6.94 1.67 0.09 1.52 SG42 0-1 3.96 0.05 0.49 1.64 1.52 . 26.41 7.53 1.68 0.12 1.22 SG42 1-2 4.48 0.06 0.52 1.71 1.64 27.75 8.22 1.70 0.11 1.55 SG42 2-3 4.15 0.05 0.50 1.68 1.83 27.09 7.23 1.64 0.10 2.05 SG42 3-4 4.05 0.05 0.50 1.65 1.75 26.95 7.27 1.79 0.09 1.75 SG42 4-5 4.27 0.05 0.49 1.64 1.75 26.62 7.19 1.81 0.10 1.59 SG42 5-6 4.26 0.05 0.49 1.68 1.79 27.00 7.21 1.72 0.10 1.67 SG42 6-7 4.31 0.06 0.50 1.70 1.85 27.52 7.36 1.72 0.11 1.69 203 Core Fe Mn Ti Ca K Si Al Mg P Na SG55 0-1 4.22 0.79 0.42 1.24 1.27 23.51 6.44 1.81 0.12 2.50 SG55 1-2 4.41 0.38 0.44 1.22 1.38 25.10 6.91 1.90 0.11 2.01 SG55 2-3 4.54 0.33 0.45 1.23 1.51 24.81 6.78 1.72 0.08 1.12 SG55 3-4 4.35 0.37 0.44 1.23 1.46 24.32 6.57 1.69 0.12 1.21 SG55 4-5 4.44 0.43 0.45 1.24 1.37 24.38 6.56 1.73 0.11 0.60 SG55 5-6 4.39 0.39 0.44 1.23 1.51 24.47 6.61 1.76 0.10 1.16 SG55 6-7 4.40 0.36 0.45 1.24 1.41 24.62 6.58 1.78 0.09 1.44 SG55 7-8 4.22 0.43 0.44 1.21 1.36 24.01 6.45 1.62 0.10 1.17 SG55 8-9 4.22 0.44 0.43 1.20 1.41 24.37 6.70 1.70 0.09 1.07 SG55 9-10 4.45 0.43 0.45 1.25 1.46 25.00 7.13 1.91 0.11 1.31 SG55 10-12 4.31 0.32 0.46 1.23 1.47 24.53 7.04 1.87 0.10 1.10 SG55 12-14 4.28 0.31 0.45 1.23 1.41 24.84 6.88 1.72 0.09 1.38 SG55 14-16 4.27 0.30 0.45 1.25 1.48 24.86 7.21 1.92 0.11 1.15 SG55 16-18 4.40 0.30 0.45 1.67 1.56 25.41 7.20 1.83 0.11 1.12 SG55 18-20 4.70 0.32 0.46 1.26 1.57 26.07 7.42 1.93 0.11 1.76 SG55 20-22 4.74 0.35 0.46 1.27 1.56 26.38 7.35 1.86 0.10 1.61 SG55 22-24 4.37 0.33 0.44 1.21 1.51 23.41 6.28 1.69 0.09 0.85 SG55 24-26 4.27 0.33 0.45 1.22 1.51 25.23 6.92 1.94 0.09 1.26 SG55 26-28 4.48 0.35 0.45 1.26 1.57 25.40 6.90 1.72 0.09 1.63 SG55 28-33 4.46 0.45 0.45 1.27 1.48 26.06 7.27 1.92 0.09 1-.67 SG55 33-35 4.17 0.32 0.43 1.20 1.60 23.94 6.47 1.62 0.08 1.04 SG55 35-40 4.57 0.31 0.46 1.26 1.58 26.14 7.62 1.87 0.10 1.93 SG55 40-45 4.32 0.29 0.46 1.20 1.53 25.19 7.18 1.84 0.09 0.96 SG55 45-50 4.37 0.27 0.46 1.23 1.56 24.42 6.89 1.81 0.11 1.15 SG55 50-55 4.28 0.26 0.44 1.26 1.64 24.94 7.09 1.81 0.11 1.83 SG55 55-60 4.52 0.30 0.44 1.25 1.58 23.85 6.64 1.63 0.10 1.16 SG55 60-65 4.65 0.33 0.46 1.30 1.61 25.94 7.23 1.82 0.11 1.08 A12 0-1 3.11 0.06 0.37 1.98 0.95 32.79 5.65 1.17 0.07 1.76 A12 1-2 2.83 0.05 0.36 1.90 0.96 33.30 5.67 1.16 0.08 1.58 A12 2-3 2.87 0.05 0.39 1.80 1.05 33.91 5.66 1.14 0.08 2.21 A12 3-4 2.78 0.05 0.38 1.65 1.01 33.99 5.69 1.10 0.07 1.67 A12 4-5 2.75 0.05 0.36 1.65 1.07 33.59 5.68 1.20 0.07 1.57 A12 5-6 2.69 0.05 0.36 1.64 1.08 33.79 5.61 1.13 0.06 1.75 A12 6-7 2.72 0.05 0.36 1.67 1.07 33.25 5.51 1.04 0.07 1.65 A12 7-8 2.78 0.05 0.38 1.70 1.07 33.82 6.00 1.03 0.07 1.53 A12 8-9 2.82 0.05 0.34 1.83 1.23 32.75 5.68 0.97 0.09 1.89 A12 9-10 2.64 0.05 0.35 1.62 1.09 33.41 5.52 1.04 0.06 1.73 A12 10-12 2.82 0.04 0.37 1.61 1.13 32.51 5.81 1.12 0.06 1.94 A12 12-14 2.74 0.04 0.37 1.66 1.19 32.82 5.77 1.17 0.07 1.64 A12 14-16 2.98 0.05 0.39 1.63 1.16 33.45 6.14 1.15 0.07 1.66 A12 16-18 2.71 0.04 0.36 1.55 1.12 32.75 5.64 1.06 0.06 1.79 A12 18-20 2.71 0.05 0.34 1.83 1.15 34.62 5.82 1.11 0.07 1.81 A12 20-22 2.87 0.05 0.39 1.65 1.14 33.14 5.92 1.13 0.06 1.54 A12 22-24 2.74 0.05 0.39 1.65 1.15 32.77 5.78 1.09 0.07 1.52 AO 0-1 3.76 0.05 0.52 1.89 1.33 30.26 7.35 1.54 0.11 1.85 AO 1-2 3.43 0.05 0.50 1.82 1.28 29.75 7.02 1.39 0.09 1.54 AO 2-3 3.57 0.05 0.48 1.72 1.41 28.87 6.92 1.39 0.09 1.60 AO 3-4 3.25 0.05 0.48 1.73 1.34 29.96 6.80 1.40 0.08 1.59 AO 4-5 3.48 0.05 0.48 1.74 1.32 30.26 6.88 1.49 0.08 1.54 AO 5-6 3.46 0.05 0.48 1.87 1.28 29.65 6.83 1.45 0.08 1.69 AO 6-7 3.51 0.05 0.47 1.87 1.28 30.33 6.72 1.40 • 0.07 1.58 AO 7-8 3.45 0.05 0.46 1.76 1.20 30.63 6.44 1.29 0.07 1.53 204 Core Fe Mn Ti Ca K Si Al Mg P Na AO 8-9 3.47 0.05 0.48 1.75 1.21 31.13 6.55 1.33 0.08 1.52 AO 9-10 3.67 0.05 0.48 1.81 1.34 30.41 6.73 . 1-51 0.07 1.57 AO 10-12 3.28 0.05 0.46 1.88 1.24 31.87 6.38 1.35 0.07 • 1.72 AO 12-14 3.12 0.05 0.43 1.77 1.17 32.10 6.12 1.42 0.06 1.86 AO 14-16 4.05 0.05 0.46 1.87 1.43 31.64 7.10 1.49 0.08 1.77 AO 16-18 4.68 0.06 0.52 1.62 1.55 26.06 7.80 1.85 0.08 1.38 AO 18-20 2.87 0.04 0.41 1.65 1.12 31.29 5.96 1.20 0.07 1.37 AO 20-22 2.58 0.04 0.39 1.63 1.07 33.60 5.63 1.14 0.07 1.65 AO 22-24 2.91 0.05 0.44 1.73 1.04 34.80 5.97 1.14 0.07 1.76 AO 24-26 2.70 0.04 0.45 1.70 0.96 33.40 5.62 1.06 0.06 1.49 AO 26-28 2.93 0.05 0.45 1.73 1.03 34.64 5.86 1.12 0.07 1.67 AO 28-30 3.16 0.05 0.42 1.71 1.11 36.27 6.06 1.07 0.07 1.74 AO 30-32 3.11 0.05 0.45 1.77 1.03 35.26 5.98 1.14 0.06 1.39 AG17 0-1 4.13 0.06 0.49 1.67 1.69 29.14 7.33 1.83 0.09 1.96 AG17 1-2 4.11 0.06 0.50 1.66 1.75 28.05 6.87 1.73 0.10 1.22 A G 17 2-3 4.12 0.06 0.50 1.69 1.72 29.49 7.45 1.80 0.10 1.90 AG17 3-4 4.02 0.06 0.49 1.58 1.69 28.78 7.35 1.81 0.09 2.02 A G 17 4-5 4.16 0.06 0.50 1.37 1.85 29.47 7.48 1.79 0.10 2.02 AG17 5-6 4.40 0.06 0.51 1.64 1.74 27.95 7.18 1.75 0.10 1.20 A G 17 6-7 4.33 0.06 0.50 1.56 1.82 29.59 7.81 1.79 0.09 2.05 AG17 7-8 4.33 0.06 0.51 1.64 1.97 29.67 7.75 1.80 0.10 2.01 A G 17 8-9 4.61 0.06 0.52 1.78 1.88 29.83 8.08 1.82 0.10 1.64 AG17 9-10 4.33 0.06 0.52 1.46 1.90 29.85 7.66 1.91 0.10 1.62 AG17 10-12 4.31 0.06 0.50 1.49 1.94 28.42 7.78 1.84 0.09 2.11 AG17 12-14 4.32 0.06 0.48 1.45 1.91 28.58 7.69 1.92 0.09 1.92 AG17 14-16 5.08 0.06 0.54 1.65 2.11 31.14 8.42 1.84 0.10 1.86 AG17 16-18 4.29 0.06 0.48 1.46 1.90 27.72 7.44 1.87 0.09 1.55 A G 17 18-20 4.41 0.06 0.49 1.47 1.88 28.17 7.64 1.84 0.10 1.70 AG17 20-22 4.45 0.06 0.49 1.56 1.91 29.15 7.91 1.86 0.09 1.90 A G 17 22-24 4.32 0.05 0.50 1.48 1.83 28.35 7.80 1.91 0.10 2.01 A G 17 24-26 4.72 0.06 0.50 1.62 1.83 30.01 8.38 1.88 0.10 1.93 A G 17 26-28 4.69 0.06 0.51 1.60 2.03 30.41 8.22 1.83 0.10 1.91 AG17 28-31 4.47 0.06 0.50 1.58 1.94 27.93 7.51 1.81 0.09 1.60 AG54 0-1 4.76 0.08 0.45 1.19 1.68 25.38 7.25 2.00 0.18 1.45 AG54 1-2 5.47 0.07 0.50 1.39 1.91 29.82 8.88 1.98 0.19 2.00 AG54 2-3 4.65 0.06 0.46 1.25 1.88 27.18 7.84 1.98 0.13 2.01 AG54 3-4 5.02 0.06 0.48 1.32 2.01 28.13 8.20 1.92 0.13 1.57 AG54 4-5 4.75 0.06 0.47 1.26 1.88 27.40 8.02 1.93 0.13 1.86 AG54 5-6 4.58 0.06 0.46 1.25 1.82 27.13 7.96 1.97 0.12 2.10 AG54 6-7 AG54 7-8 4.69 0.06 0.45 1.17 1.77 26.67 7.91 1.92 0.11 1.63 AG54 8-9 4.58 0.06 0.47 1.22 1.86 27.22 7.95 2.01 0.11 2.02 AG54 9-10 4.65 0.06 0.47 1.23 1.93 27.85 8.09 1.99 0.11 1.97 AG54 10-12 4.54 0.06 0.46 1.21 1.83 26.96 8.01 1.99 0.10 1.83 AG54 12-14 4.77 0.06 0.46 1.25 1.94 25.62 7.23 1.86 0.09 1.01 AG54 14-16 4.60 0.06 0.45 1.15 1.92 26.97 7.77 1.93 0.09 1.91 AG54 16-18 4.53 0.06 0.45 1.16 1.93 26.55 7.64 1.99 0.09 1.89 AG54 18-20 5.18 0.06 0.50 1.36 1.90 29.69 8.82 1.93 0.10 1.83 AG54 20-22 4.60 0.06 0.45 1.19 1.73 27.54 8.08 1.94 0.10 1.42 AG54 22-24 4.47 0.06 0.46 1.19 1.76 26.24 7.60 1.94 0.09 1.78 AG54 24-26 4.56 0.06 0.46 1.17 1.79 27.54 8.15 1.96 0.10 2.22 AG54 26-28 4.54 0.06 0.47 1.16 1.74 27.00 8.00 1.95 0.09 1.84 205 Core Fe Mn Ti Ca K Si Al Mg P Na AG54 28-30 4.66 0.06 0.46 1.23 1.80 27.04 8.02 1.93 0.09 1.59 AG54 30-35 4.56 0.06 0.46 1.34 1.95 27.95 8.13 1.98 0.10 1.83 AG54 35-40 4.66 0.06 0.47 1.22 1.89 27.13 8.10 2.01 0.09 1.75 AG54 40-45 4.56 0.06 0.46 1.19 1.89 25.84 7.72 2.03 0.09 1.47 AG54 45-50 4.61 0.06 0.46 1.22 1.88 26.69 7.97 2.01 0.09 2.05 AG54 50-55 4.67 0.06 0.46 1.15 2.03 27.21 8.31 2.03 0.09 1.81 AG54 55-60 4.59 0.06 0.46 1.16 2.09 26.95 8.15 1.97 0.09 2.03 AG54 60-65 4.61 0.06 0.45 1.21 2.04 27.17 8.25 2.04 0.09 1.89 206 Table A4.8 Minor and major element to aluminum ratios for core samples from the Strait of Georgia. Values are multiplied by 10 4 except for Ag/Al , T i /A l , and P/Al which are multiplied by 10 6 ,10 3 , and 10 3, respectively. Values are listed on a salt free basis. Core Ag/Al (*lE+06) Pb/Al Zr/Al Y/Al Sr/Al Rb/Al Zn/AI Cu/AI Ni/Al Co/Al Mn/Al V/Al Cr/Al Ba/Al SG4 0-1 2.8: 1.7' 17.4S 2.72 3i 10.16 16.38 5.5; 7.12 2.76 258 24.6S 16.52 82.84 SG4 1-2 2.5-1 1.92 17.15 2.52 31 8.4S 16.44 5.92 6.9C 1.67 127 22.51 15.12 75.89 SG4 2-3 2.81 1.86 17.77 2.71 3' 9.43 17.13 6.0C 7.7' 1.86 131 24.30 16.78 82.11 SG4 3-4 2.73 1.95 16.65 2.85 35 10.31 16.86 5.85 7.0S 2.09 120 22.99 15.91 79.74 SG4 4-5 2.55 2.16 17.49 2.55 34 9.61 16.80 6.5S 7.02 2.62 114 22.31 15.21 79.26 SG4 5-6 2.66 2.11 17.13 2.54 33 9.02 17.21 6.53 6.51 2.11 112 23.00 16.00 79.90 SG4 6-7 3.03 3.06 17.88 3.18 33 9.13 16.59 6.07 6.60 2.16 105 21.96 15.70 74.35 SG4 7-8 3.27 2.32 18.28 2.49 33 9.93 17.37 6.61 7.06 2.02 108 22.48 15.91 80.18 SG4 8-9 2.57 2.52 17.76 2.80 33 9.92 17.09 6.27 6.78 2.34 106 22.87 16.01 81.36 SG4 9-10 2.96 3.38 17.37 2.39 34 9.58 17.02 6.10 6.84 2.87 100 22.18 16.04 79.61 SG4 10-12 17.46 2.92 32 9.02 16.47 5.83 6.79 2.20 101 22.10 16.17 80.20 SG4 12-14 17.72 2.95 33 8.77 16.35 6.03 6.77 2.24 99 21.89 15.64 79.19 SG4 14-16 2.92 3.46 18.14 2.42 32 10.06 16.92 6.11 6.54 2.66 101 21.74 15.95 75.31 SG4 16-18 17.10 2.68 31 10.11 17.17 6.12 7.22 2.77 102 22.25 15.65 77.87 SG4 18-20 2.85 3.67 17.71 2.88 33 10.61 17.84 6.77 7.51 2.56 106 22.32 15.83 81.51 SG4 20-22 2.73 3.39 17.79 3.00 32 11.46 18.30 6.23 7.46 2.35 100 21.64 15.39 78.08 SG4 22-24 2.86 4.39 18.04 2.64 32 11.15 18.30 6.84 7.62 2.19 104 22.76 16.16 81.69 SG4 24-26 17.55 2.74 32 10.26 18.54 5.99 8.06 2.64 106 23.67 16.29 84.81 SG4 26-28 3.40 3.72 17.59 2.68 31 9.75 18.12 6.49 7.43 2.40 103 22.01 15.55 80.62 SG4 28-30 16.59 3.47 31 9.46 17.96 6.05 7.86 1.79 102 21.39 15.09 77.92 SG4 30-35 2.85 3.53 18.61 2.64 33 10.89 18.39 6.24 7.70 2.64 112 23.04 16.16 85.09 SG4 35-40 18.85 3.46 33 8.76 18.46 6.23 7.7S 2.57 118 22.86 16.24 83.70 SG4 40-45 2.79 3.51 17.55 3.58 33 9.43 18.26 6.56 7.39 2.63 142 23.68 16.56 85.62 SG17 0-1 8.03 1.90 22.88 2.83 37 8.92 14.35 6.50 7.50 2.13 92 22.53 19.92 91.47 SG17 1-2 8.12 1.98 23.06 2.94 37 9.57 14.69 6.83 7.65 2.70 84 20.72 18.97 89.32 SGI 7 2-3 7.63 2.25 24.72 3.78 37 10.61 16.25 6.70 7.61 2.40 89 22.22 19.66 95.31 SG17 3-4 7.47 2.22 23.17 3.58 37 11.09 15.95 6.77 7.71 2.11 87 21.63 19.73 93.03 SGI 7 4-5 8.43 2.21 23.44 3.20 37 9.96 15.85 6.33 7.63 2.35 90 22.40 19.30 96.99 SG17 5-6 7.44 2.22 23.42 3.17 37 8.78 15.96 6.76 7.89 2.56 88 22.46 19.35 96.30 SG17 6-7 8.47 2.23 24.26 3.40 38 10.24 15.83 6.88 8.09 2.07 85 21.35 18.76 94.67 SG290-1 9.97 2.14 22.94 2.66 36 8.29 14.22 6.59 6.72 2.23 85 22.88 20.94 89.59 SG29 1-2 10.30 2.49 25.37 2.97 40 10.84 16.70 837 7.61 2.38 88 22.00 19.98 93.27 SG29 2-3 10.47 2.32 25.89 3.16 39 11.19 17.27 8.44 7.79 2.46 91 23.10 20.69 98.19 SG29 3-4 10.07 2.26 24.03 3.29 36 9.58 16.13 7.63 8.20 2.44 86 22.39 19.39 95.97 SG29 4-5 12.22 2.42 24.14 3.00 37 10.35 16.12 7.24 8.03 2.41 87 22.08 19.52 95.58 SG29 5-6 10.32 2.44 25.52 3.28 38 10.00 16.64 7.64 7.35 3.29 90 22.73 20.08 97.09 SG29 6-7 10.41 2.28 25.21 3.39 37 10.68 16.00 7.54 7.97 2.37 86 21.83 19.48 91.95 SG42 0-1 9.25 2.09 20.31 2.84 35 9.26 15.25 7.48 6.95 2.29 85 20.85 17.47 84.81 SG42 1-2 8.69 2.00 18.33 2.70 31 9.14 14.23 6.48 6.29 1.82 76 19.49 15.65 78.32 SG42 2-3 9.43 2.38 20.53 3.27 35 10.11 16.93 7.59 7.68 2.21 86 21.83 18.24 91.84 SG42 3-4 9.96 2.41 21.01 2.91 35 10.56 16.35 7.27 8.13 2.18 84 21.73 17.72 91.32 SG42 4-5 8.93 2.39 21.55 3.99 34 10.37 16.37 6.91 7.93 2.37 85 21.58 18.15 90.40 SG42 5-6 9.59 2.50 20.81 3.97 36 10.46 16.66 7.31 7.85 2.49 86 22.29 18.21 92.04 SG42 6-7 8.40 2.36 20.18 3.41 35 9.94 16.13 7.27 7.65 2.48 85 22.101 17.68 88.92 207 Core Ag/Al (*lE+06) Pb/Al Zr/Al Y/Al Sr/Al Rb/Al Zn/Al Cu/Al Ni/Al Co/Al Mn/Al V/Al Cr/Al Ba/Al SG55 0-1 1.97 15.08 3.32 46 11.86 20.64 6.95 8.75 3.53 1472 26.59 14.65 85.33 SG55 1-2 1.93 15.22 2.88 40 10.93 19.54 7.53 8.15 3.38 743 28.39 15.72 88.04 SG55 2-3 1.93 16.23 3.01 37 9.64 20.64 7.18 7.69 3.03 595 27.69 15.65 84.77 SG55 3-4 2.19 16.54 2.73 42 11.39 21.78 7.46 8.08 2.83 738 29.14 16.51 87.42 SG55 4-5 2.13 16.01 3.34 39 11.33 21.19 7.00 8.07 3.52 801 29.93 16.84 91.38 SG55 5-6 1.83 15.81 2.46 38 10.86 21.87 7.68 8.11 3.15 772 29.21 16.52 91.60 SG55 6-7 1.96 16.92 1.98 37 11.54 22.18 7.79 8.67 3.05 726 28.93 16.40 89.17 SG55 7-8 2.07 16.23 3.60 39 10.56 23.62 8.10 8.57 3.58 889 28.33 16.69 89.53 SG55 8-9 1.86 16.26 3.04 35 11.50 22.27 8.06 8.19 3.34 883 27.75 15.75 85.33 SG55 9-10 15.20 3.12 33 10.38 21.43 7.20 8.22 3.07 754 26.22 15.06 79.90 SG55 10-12 2.00 15.36 2.71 34 10.45 21.74 7.11 8.10 3.21 602 26.30 15.37 81.92 SG55 12-14 16.16 3.14 35 10.32 22.80 7.83 8.68 3.25 617 27.89 16.25 87.60 SG55 14-16 1.97 15.20 2.33 33 9.60 21.59 7.50 7.67 3.28 554 25.80 14.99 82.91 SG55 16-18 15.31 3.12 34 11.07 20.58 7.56 7.98 3.15 546 27.63 16.10 88.00 SG55 18-20 1.65 14.67 2.81 33 10.63 19.57 7.19 7.56 3.05 561 25.28 14.90 82.17 SG55 20-22 14.71 3.17 33 10.57 20.21 6.92 7.02 3.26 605 25.28 14.48 77.03 SG55 22-24 1.84 17.51 3.01 38 11.67 23.16 8.02 8.86 3.92 705 30.60 17.05 97.67 SG55 24-26 15.68 2.61 34 10.01 20.76 7.70 7.92 3.80 625 26.43 15.60 86.23 SG55 26-28 1.57 15.45 3.25 34 12.40 20.08 7.65 7.82 3.16 691 28.09 16.57 90.13 SG55 28-33 14.63 2.57 33 11.30 18.78 7.23 7.20 3.18 827 25.59 14.72 81.06 SG55 33-35 17.00 3.05 36 12.41 20.66 7.74 8.61 3.38 679 27.82 16.45 95.23 SG55 35-40 14.03 2.50 32 10.91 16.98 6.69 7.33 2.97 503 23.52 13.44 77.51 SG55 40-45 1.36 15.32 2.89 33 11.03 17.29 6.67 7.65 3.28 513 26.01 14.86 85.29 SG55 45-50 15.73 2.78 35 11.35 16.99 6.73 8.13 3.11 516 27.23 15.27 85.91 SG55 50-55 15.78 2.78 34 11.10 16.19 6.78 7.90 3.46 478 26.36 14.54 83.07 SG55 55-60 1.39 16.07 3.13 36 11.30 17.14 5.95 8.92 3.26 583 27.82 15.56 90.53 SG55 60-65 15.35 3.09 32 9.84 16.58 6.19 7.77 2.93 568 25.87 15.10 84.86 A12 0-1 1.16 1.57 14.09 3.13 45 5.16 10.72 2.17 4.83 20.64 114 18.49 16.08 89.36 A12 1-2 1.06 1.74 16.77 3.49 45 5.05 11.27 2.32 6.10 8.42 118 20.28 20.53 88.36 A12 2-3 0.94 1.44 16.21 2.58 45 5.33 10.87 1.21 4.95 23.32 105 18.01 16.89 91.26 A12 3-4 1.25 1.87 21.52 2.95 45 5.59 11.52 2.28 5.45 21.00 101 18.79 18.29 90.10 A12 4-5 1.11 1.53 19.30 3.16 46 6.19 11.72 2.00 5.50 11.93 98 18.98 18.65 97.32 A12 5-6 1.54 1.88 20.04 2.58 47 5.86 11.44 2.28 5.77 9.20 97 19.27 18.72 98.38 A12 6-7 1.40 1.74 20.52 2.95 47 6.55 10.94 1.73 4.98 18.31 100 19.84 19.37 96.23 A12 7-8 1.49 1.74 19.01 2.59 43 5.52 11.25 2.18 5.67 15.85 87 17.52 16.67 86.79 A12 8-9 2.05 1.82 21.39 2.46 48 7.27 12.33 2.80 5.06 24.11 96 19.46 17.85 95.89 A12 9-10 1.18 1.61 19.53 2.38 47 5.02 11.16 2.46 5.41 20.15 90 18.08 15.75 93.78 A12 10-12 1.78 1.82 22.41 2.96 45 8.00 12.70 3.57 6.69 19.28 94 19.61 18.27 100.24 A12 12-14 1.52 1.64 24.43 3.19 45 7.00 11.90 2.98 6.09 19.73 91 18.37 18.30 96.08 A12 14-16 1.33 1.40 21.12 2.38 43 5.44 11.06 3.77 5.88 13.21 88 18.11 17.37 91.74 A12 16-18 1.55 21.30 2.28 45 6.32 11.21 3.55 5.91 12.58 98 19.72 18.95 96.87 A12 18-20 0.99 1.50 19.07 2.94 46 6.81 9.97 2.59 5.46 18.79 97 17.82 16.80 90.98 A12 20-22 1.36 21.14 2.68 44 6.09 10.87 2.92 6.40 14.46 99 18.91 18.86 98.92 A12 22-24 0.97 24.60 3.50 44 5.57 10.04 4.04 5.39 23.92 103 19.29 21.45 98.98 AO 0-1 17.72 2.99 26.01 3.03 38 7.96 14.30 6.24 6.31 1.94 81 20.00 20.60 89.90 AO 1-2 31.13 4.43 26.62 2.91 38 8.10 17.10 8.73 6.96 2.46 80 20.60 22.70 91.00 AO 2-3 44.81 6.29 25.40 2.71 . 38 9.72 18.70 10.20 7.78 2.17 86 21.90 22.20 96.80 AO 3-4 48.88 8.80 25.44 3.02 40 7.95 19.00 9.23 7.31 2.15 84 21.10 23.60 97.40 AO 4-5 32.07 4.47 24.78 2.06 40 8.09 17.40 8.20 6.75 1.93 84 21.10 24.90 93.80 AO 5-6 18.62 2.82 24.18 2.99 41 7.76 15.50 6.91 7.73 2.28 90 22.10 22.90 94.10 AO 6-7 15.45 2.72 25.98 2.74 40 8.14 15.10 5.30 7.23 2.19 89 22.10 22.70 93.60 AO 7-8 11.90 2.45 24.91 3.11 42 7.59 14.40 5.22 6.93 2.70 90 22.00 23.80 95.50 208 Core Ag/Al (*lE+06) Pb/Al Zr/Al Y/Al Sr/Al Rb/Al Zn/Al Cu/AI Ni/Al Co/Al Mn/Al V/Al Cr/Al Ba/Al AO 8-9 9.28 2.12 26.08 3.23 41 8.14 14.90 5.19 7.54 2.43 92 22.60 24.30 97.70 AO 9-10 8.60 2.29 24.59 2.83 40 7.14 14.30 5.00 6.88 2.35 91 22.00 22.60 91.40 AO 10-12 25.73 3.11 44 7.70 13.20 4.89 6.60 2.81 91 21.10 25.10 97.70 AO 12-14 3.03 1.95 24.64 2.87 45 8.47 13.40 4.58 7.13 2.50 89 21.40 24.70 100.00 AO 14-16 22.68 2.93 37 8.60 14.10 5.84 7.23 2.52 84 20.30 19.60 91.70 AO 16-18 3.33 2.26 19.48 2.73 32 9.38 17.10 7.63 8.93 2.88 86 21.90 17.90 88.90 AO 18-20 24.11 2.59 45 6.94 12.40 4.10 6.33 1.96 90 21.20 21.80 102.00 AO 20-22 1.23 26.67 3.06 48 6.17 10.40 5.90 6.29 84 18.10 19.70 98.50 AO 22-24 27.84 3.04 45 6.04 9.99 4.13 5.60 78 17.40 19.50 93.60 AO 24-26 1.00 1.42 27.80 2.29 47 7.88 10.50 2.53 5.75 80 18.20 19.40 96.60 AO 26-28 24.64 3.29 44 5.89 9.76 2.47 5.82 81 18.20 21.20 98.90 AO 28-30 0.88 25.10 2.89 44 5.59 9.72 1.99 5.64 79 17.30 19.80 92.70 AO 30-32 25.86 3.11 45 6.54 9.64 1.93 5.89 80 18.20 21.10 93.70 AG17 0-1 9.53 1.69 AG17 1-2 9.75 2.37 AG17 2-3 8.98 2.12 AG17 3-4 8.82 1.44 A G 17 4-5 10.42 2.08 AG17 5-6 9.19 2.27 AG17 6-7 7.59 1.34 AG17 7-8 7.53 2.48 AG17 8-9 5.53 2.47 AG17 9-10 5.18 1.62 AG17 10-12 4.90 2.36 AG17 12-14 4.80 2.78 AG17 14-16 3.83 1.87 AG17 16-18 4.33 2.72 AG17 18-20 4.18 2.54 AG17 20-22 3.96 1.69 AG17 22-24 3.88 2.53 AG17 24-26 5.15 2.24 AG17 26-28 4.03 1.55 AG17 28-31 4.53 1.00 AG54 0-1 5.39 2.43 AG54 1-2 5.16 3.10 AG54 2-3 5.52 2.44 AG54 3-4 5.23 2.32 AG54 4-5 5.34 2.39 AG54 5-6 5.39 2.62 AG54 6-7 AG54 7-8 6.12 3.10 AG54 8-9 5.58 3.04 AG54 9-10 5.52 3.11 AG54 10-12 4.31 4.06 AG54 12-14 4.41 4.49 AG54 14-16 4.27 2.46 AG54 16-18 4.28 4.18 AG54 18-20 3.75 3.69 AG54 20-22 4.03 2.86 AG54 22-24 4.31 4.44 AG54 24-26 3.97 4.54 AG54 26-28 4.25 4.30 209 Core Ag/Al (*lE+06) Pb/Al Zr/Al Y/Al Sr/Al Rb/Al Zn/Al Cu/AI Ni/Al Co/Al Mn/Al V/Al Cr/Al Ba/Al AG54 28-30 4.32 3.98 AG54 30-35 4.26 3.81 AG54 35-40 4.18 3.86 AG54 40-45 3.52 3.77 AG54 45-50 2.73 3.20 AG54 50-55 2.60 2.81 AG54 55-60 2.26 3.00 AG54 60-65 1.98 2.86 210 Core Fe/Al Ti/Al (*lE+03) Ca/Al K/Al Si/Al Mg/Al P/Al (*lE+03) SG4 0-1 0.61 64.67 0.15 0.20 3.60 0.21 18.83 SG4 1-2 0.60 64.25 0.14 0.19 3.55 0.24 15.59 SG4 2-3 0.61 65.51 0.15 0.22 3.66 0.24 16.34 SG4 3-4 0.61 66.02 0.14 0.19 3.57 0.23 13.11 SG4 4-5 0.59 63.59 0.15 0.21 3.55 0.24 14.39 SG4 5-6 0.60 64.06 0.15 0.23 3.58 0.24 14.30 SG4 6-7 0.59 65.21 0.15 0.22 3.60 0.22 13.12 SG4 7-8 0.59 66.73 0.16 0.21 3.61 0.22 12.79 SG4 8-9 0.60 66.16 0.17 0.22 3.65 0.22 13.31 SG4 9-10 0.59 64.57 0.15 0.22 3.58 0.20 12.07 SG4 10-12 0.59 65.47 0.16 0.23 3.59 0.21 13.62 SG4 12-14 0.59 64.67 0.17 0.22 3.58 0.22 12.39 SG4 14-16 0.58 66.02 0.17 0.22 3.61 0.21 12.48 SG4 16-18 0.57 64.79 0.15 0.23 3.58 0.23 12.87 SG4 18-20 0.59 65.04 0.15 0.21 3.61 0.22 13.89 SG4 20-22 0.58 65.23 - 0.15 0.21 3.58 0.23 11.72 SG4 22-24 0.60 66.16 0.16 0.21 3.61 0.22 12.68 SG4 24-26 0.60 65.11 0.15 0.22 3.64 0.23 13.72 SG4 26-28 0.59 65.68 0.16 0.24 3.66 0.23 13.49 SG4 28-30 0.60 64.18 0.15 0.21 3.58 0.23 13.01 SG4 30-35 0.59 67.69 0.16 0.21 3.63 0.24 12.64 SG4 35-40 0.60 67.03 0.16 0.23 3.68 0.21 12.04 SG4 40-45 0.60 67.07 0.17 0.21 3.64 0.23 13.60 SG17 0-1 0.53 67.68 0.19 0.20 3.80 0.22 14.35 SG17 1-2 0.55 69.66 0.18 0.22 3.95 0.23 13.15 SGI 7 2-3 0.54 71.06 0.19 0.25 3.99 0.22 12.78 SGI 7 3-4 0.54 70.14 0.18 0.24 3.93 0.23 13.87 SG17 4-5 0.57 69.43 0.17 0.24 3.95 0.24 12.64 SG17 5-6 0.55 69.74 0.17 0.25 4.02 0.25 12.85 SGI 7 6-7 0.54 71.29 0.18 0.25 4.08 0.24 14.27 SG29 0-1 0.52 67.95 0.20 0.20 3.81 0.22 12.83 SG29 1-2 0.56 73.01 0.21 0.26 4.09 0.25 13.95 SG29 2-3 0.57 72.77 0.22 0.26 4.04 0.24 13.91 SG29 3-4 0.55 71.88 0.19 0.23 3.91 0.24 14.04 SG29 4-5 0.55 71.88 0.20 0.24 3.94 0.24 12.77 SG29 5-6 0.56 72.98 0.20 0.24 4.03 0.24 13.78 SG29 6-7 0.54 72.50 0.19 0.23 3.96 0.24 13.52 SG42 0-1 0.53 65.39 0.16 0.20 3.51 0.22 15.87 SG42 1-2 0.55 62.84 0.15 0.20 3.37 0.21 13.78 SG42 2-3 0.57 68.69 0.17 0.25 3.75 0.23 14.38 SG42 3-4 0.56 68.18 0.17 0.24 3.71 0.25 13.03 SG42 4-5 0.59 68.85 0.17 0.24 3.70 0.25 13.79 SG42 5-6 0.59 68.18 0.17 0.25 3.74 0.24 14.27 SG42 6-7 0.59 67.90 0.17 0.25 3.74 0.23 14.65 211 Core Fe/Al Ti/Al (*lE+03) Ca/Al K/Al Si/Al Mg/Al P/Al (*lE+03) SG55 0-1 0.66 64.92 0.15 0.20 3.65 0.28 18.91 SG55 1-2 0.64 63.54 0.14 0.20 3.63 0.27 15.65 SG55 2-3 0.67 66.51 0.15 0.22 3.66 0.25 11.76 SG55 3-4 0.66 67.66 0.15 0.22 .3.70 0.26 17.85 SG55 4-5 0.68 68.29 0.15 0.21 3.72 0.26 16.34 SG55 5-6 0.66 65.88 0.15 0.23 3.70 0.27 14.81 SG55 6-7 0.67 67.99 0.15 0.21 3.74 0.27 14.14 SG55 7-8 0.65 68.55 0.14 0.21 3.72 0.25 15.19 SG55 8-9 0.63 64.83 0.11 0.21 3.64 0.25 13.88 SG55 9-10 0.62 62.57 0.13 0.20 3.51 0.27 14.97 SG55 10-12 0.61 64.98 0.13 0.21 3.49 0.27 14.46 SG55 12-14 0.62 65.86 0.14 0.20 3.61 0.25 13.51 SG55 14-16 0.59 62.67 0.14 0.21 3.45 0.27 14.78 SG55 16-18 0.61 62.87 0.20 0.22 3.53 0.25 14.83 SG55 18-20 0.63 62.68 0.13 0.21 3.52 0.26 15.00 SG55 20-22 0.65 62.49 0.13 0.21 3.59 0.25 13.27 SG55 22-24 0.70 69.96 0.15 0.24 3.73 0.27 14.03 SG55 24-26 0.62 65.43 0.14 0.22 3.64 0.28 12.75 SG55 26-28 0.65 65.54 0.14 0.23 3.68 0.25 13.44 SG55 28-33 0.61 62.38 0.12 0.20 3.59 0.26 12.79 SG55 33-35 0.65 67.26 0.13 0.25 3.70 0.25 12.96 SG55 35-40 0.60 60.36 0.12 0.21 3.43 0.25 13.43 SG55 40-45 0.60 63.71 0.12 0.21 3.51 0.26 12.88 SG55 45-50 0.63 67.27 0.14 0.23 3.54 0.26 15.43 SG55 50-55 0.60 62.62 0.14 0.23 3.52 0.25 14.98 SG55 55-60 0.68 66.96 0.15 0.24 3.59 0.25 14.63 SG55 60-65 0.64 63.26 0.13 0.22 3.59 0.25 15.35 A12 0-1 0.55 66.18 0.35 0.17 5.81 0.21 13.21 A12 1-2 0.50 62.68 0.33 0.17 5.87 0.20 13.92 A12 2-3 0.51 69.19 0.31 . 0.19 5.99 0.20 13.95 A12 3-4 0.49 66.62 0.28 0.18 5.97 0.19 11.55 A12 4-5 0.48 63.57 0.28 0.19 5.91 0.21 11.57 A12 5-6 0.48 63.40 0.28 0.19 6.03 0.20 10.95 A12 6-7 0.49 65.60 0.29 0.19 6.04 0.19 12.74 A12 7-8 0.46 63.20 0.26 0.18 5.63 0.17 11.69 A12 8-9 0.50 60.45 0.27 0.22 5.76 0.17 16.21 A12 9-10 0.48 63.29 0.29 0.20 6.05 0.19 11.12 A12 10-12 0.48 64.36 0.26 0.19 5.59 0.19 10.58 A12 12-14 0.47 64.84 0.27 0.21 5.69 0.20 11.42 A12 14-16 0.49 62.86 0.25 0.19 5.45 0.19 12.16 A12 16-18 0.48 63.10 0.26 0.20 5.81 0.19 10.12 A12 18-20 0.47 58.03 0.26 0.20 5.95 0.19 11.32 A12 20-22 0.48 65.12 0.26 0.19 5.59 0.19 10.37 A12 22-24 0.47 66.74 0.27 0.20 5.67 0.19 11.39 AO 0-1 0.51 70.99 0.23 0.18 4.12 0.21 15.63 AO 1-2 0.49 71.43 0.24 0.18 4.24 0.20 12.53 AO 2-3 0.52 69.75 0.24 0.20 4.17 0.20 12.70 AO 3-4 0.48 70.12 0.25 0.20 4.40 0.21 12.28 AO 4-5 0.51 70.18 0.24 0.19 4.40 0.22 12.14 AO 5-6 0.51 69.74 0.24 0.19 4.34 0.21 11.57 AO 6-7 0.52 70.00 0.21 0.19 4.51 0.21 11.11 AO 7-8 0.54 72.07 0.25 0.19 4.76 0.20 11.59 212 Core Fe/Al Ti/Al (*lE+03) Ca/Al K/Al Si/Al Mg/Al P/Al (*lE+03) AO 8-9 0.53 73.66 0.24 0.18 4.75 0.20 12.07 AO 9-10 0.55 70.84 0.23 0.20 4.52 0.22 9.79 AO 10-12 0.51 71.91 0.27 0.20 5.00 0.21 11.71 AO 12-14 0.51 71.09 0.27 0.19 5.25 0.23 10.07 AO 14-16 0.57 64.86 0.24 0.20 4.46 0.21 11.19 AO 16-18 0.60 67.13 0.18 0.20 3.34 0.24 10.23 AO 18-20 0.48 69.01 0.26 0.19 5.25 0.20 11.08 AO 20-22 0.46 69.65 0.28 0.19 5.97 0.20 11.70 AO 22-24 0.49 73.82 0.29 0.17 5.83 0.19 11.78 AO 24-26 0.48 79.44 0.30 0.17 5.95 0.19 10.94 AO 26-28 0.50 76.12 0.29 0.18 5.91 0.19 11.23 AO 28-30 0.52 68.61 0.28 0.18 5.98 0.18 10.86 AO 30-32 0.52 75.64 0.29 0.17 5.90 0.19 10.28 AG17 0-1 0.56 66.87 0.23 0.23 3.98 0.25 12.94 AG17 1-2 0.60 72.69 0.24 0.26 4.08 0.25 14.38 AG17 2-3 0.55 66.86 0.23 0.23 3.96 0.24 13.22 AG17 3-4 0.55 66.08 0.21 0.23 3.91 0.25 12.79 AG17 4-5 0.56 66.57 0.18 0.25 3.94 0.24 13.17 AG17 5-6 0.61 70.89 0.23 0.24 3.89 0.24 14.30 AG17 6-7 0.55 64.14 0.20 0.23 3.79 0.23 11.96 AG17 7-8 0.56 65.64 0.21 0.25 3.83 0.23 12.67 AG17 8-9 0.57 63.81 0.22 0.23 3.69 0.23 12.72 AG17 9-10 0.56 67.33 0.19 0.25 3.90 0.25 12.84 AG17 10-12 0.55 63.80 0.19 0.25 3.65 0.24 12.04 AG17 12-14 0.56 63.10 0.19 0.25 3.72 0.25 12.21 AG17 14-16 0.60 64.05 0.20 0.25 3.70 0.22 12.19 AG17 16-18 0.58 64.43 0.20 0.26 3.73 0.25 12.63 A G 17 18-20 0.58 64.26 0.19 0.25 3.69 0.24 12.87 AG17 20-22 0.56 61.89 0.20 0.24 3.68 0.23 11.83 AG17 22-24 0.55 63.62 0.19 0.24 3.64 0.24 12.58 AG17 24-26 0.56 59.99 0.19 0.22 3.58 0.22 11.72 AG17 26-28 0.57 62.59 0.19 0.25 3.70 0.22 11.94 AG17 28-31 0.59 66.05 0.21 0.26 3.72 0.24 11.87 AG54 0-1 0.66 61.63 0.16 0.23 3.50 0.28 25.36 AG54 1-2 0.62 56.52 0.16 0.22 3.36 0.22 21.88 AG54 2-3 0.59 59.31 0.16 0.24 3.47 0.25 16.92 AG54 3-4 0.61 58.73 0.16 0.24 3.43 0.23 15.55 AG54 4-5 0.59 58.38 0.16 0.23 3.42 0.24 15.87 AG54 5-6 0.58 57.56 0.16 0.23 3.41 0.25 15.29 AG54 6-7 AG54 7-8 0.59 57.34 0.15 0.22 3.37 0.24 14.30 AG54 8-9 0.58 58.62 0.15 0.23 3.43 0.25 13.66 AG54 9-10 0.57 58.32 0.15 0.24 3.44 0.25 13.41 AG54 10-12 0.57 57.29 0.15 0.23 3.37 0.25 12.40 AG54 12-14 0.66 63.49 0.17 0.27 3.54 0.26 13.12 AG54 14-16 0.59 57.59 0.15 0.25 3.47 0.25 11.65 AG54 16-18 0.59 59.31 0.15 0.25 3.47 0.26 11.83 AG54 18-20 0.59 57.09 0.15 0.22 3.37 0.22 11.80 AG54 20-22 0.57 55.44 0.15 0.21 3.41 0.24 12.33 AG54 22-24 0.59 60.34 0.16 0.23 3.45 0.26 11.87 AG54 24-26 0.56 57.01 0.14 0.22 3.38 0.24 12.18 AG54 26-28 0.57 58.71 0.15 0.22 3.37 0.24 11.81 213 Core Fe/Al Ti/Al (*lE+03) Ca/Al K/Al Si/Al Mg/Al P/Al (*lE+03) AG54 28-30 0.58 57.78 0.15 0.22 3.37 0.24 11.78 AG54 30-35 0.56 57.16 0.17 0.24 3.44 0.24 12.21 AG54 35-40 0.58 58.16 0.15 0.23 3.35 0.25 11.70 AG54 40-45 0.59 59.36 0.15 0.25 3.35 0.26 11.68 AG54 45-50 0.58 58.34 0.15 0.24 3.35 0.25 11.89 AG54 50-55 0.56 55.17 0.14 0.24 3.27 0.24 11.40 AG54 55-60 0.56 56.82 0.14 0.26 3.31 0.24 11.03 AG54 60-65 0.56 54.94 0.15 0.25 3.30 0.25 10.96 214 Table A4.9 Silver concentrations for surface sediments from the same site but sampled in different years. Year and month of sampling are indicated with the month in brackets. Each value represents a different sample. Values are in ppb. Sample locations are listed in Appendix 2. Sample 5903 was collected in 1993 by the Institute of Ocean Sciences and samples 1995* were collected by Simon Fraser University. Date AO A10 A12 A14 W6 W7 W8 SG29/ SG27/ SG39/ SG50/ 5903/ AG17 AG16 AG18 AG25 SG52 1993 (11) 273 1995 (7-8) 1303 63 65 109 449 49 51 771 410 399 430 262 1995* (7- 1074 62 42 112 447 46 47 1500 129 868 1996 (7) 888 55 49 113 289 698 436 497 564 215 Table A4.10 Silver concentrations in ppb for surface sediments from other locations in British Columbia. Samples from Saanich Inlet, a seasonally anoxic basin, were sampled from the middle of the inlet with samples SAG1,SAG3 and SAG4 from near the head of the inlet (Francois, 1987). Howe Sound is located north of the Strait of Georgia, samples KD71 and KD74 are located near Britannia Mine and KD18 is located northeast of Bowen Island in the outer basin of Howe Sound (Drysdale, 1990). lervis and Knight Inlets are located up the coast and are oxic inlets. Indian Arm is located to the northeast of Vancouver and connects to Burrard Inlet. Sample Ag JV7 0-1 (Jervis Inlet) 200 KN1 0-0.5 (Knight Inlet) 134 KD18 0-2 (Howe Sound) 229 KD71 0-2 (Howe Sound) 246 KD74 0-2 (Howe Sound) 134 STN18 0-2 (Indian Arm) 816 STN35 0-2 (Indian Arm) 1073 SAG1 (Saanich Inlet) 266 SAG3 (Saanich Inlet) 197 SAG4 (Saanich Inlet) 233 SAG26 (Saanich Inlet) 159 216 Table A4.11 Silver concentrations in ppb for particle size fractions for various samples. Other samples were separated into the same particle size fractions and used to determine relationships between particle size and elemental data. >125 nm 63-125 urn <63 p:m Sample Total Ag wt. % Ag (ppb) wt. % Ag (ppb) wt. % Ag (ppb) SG56 2-3 cm 130 0 0 - 100.00 153 SG32 269 0.03 295 0.91 825 94.91 419 SG31 426 0.17 445 1.76 417 98.07 469 AG17 675 0.77 260 7.91 672 88.74 1047 AG16 424 3.99 355 23.08 399 69.92 566 AG14 226 1.66 431 41.42 240 54.86 301 AG13 160 2.81 273 40.07 176 54.62 206 HC16 414 11.55 1330 42.58 310 41.75 531 HC2 56 98.63 56 0.57 164 0.18 484 A14 112 30.11 100 26.74 156 42.23 138 A12-96 49 89.73 58 9.61 105 0.57 157 SG21 - 0 - 1.34 - 98.66 -SG23 , - 0.67 - 3.43 - 95.73 -SG26 - 42.59 - 18.26 - 6.37 -A O - 3.96 - 12.57 - 83.48 -K A 1 - 11.63 - 54.60 - 33.77 -K A 2 - 47.86 - 45.71 - 6.43 -W6 - 9.58 - 50.99 - 39.36 -W7 - 65.32 - 33.99 - 0.69 -W8 - 81.46 - 17.71 - 0.83 -A12 - 97.18 - 2.41 - 0.14 -217 

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