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Perfluorinated compounds in landfill leachate from discarded carpets Shoaeioskouei, Saba 2012-12-31

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PERFLUORINATED COMPOUNDS IN LANDFILL LEACHATE FROM DISCARDED CARPETS by SABA SHOAEIOSKOUEI  B.Sc., Sharif University of Technology, 2010  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in The Faculty of Graduate Studies (Civil Engineering)  THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver)  June 2012  © Saba Shoaeioskouei, 2012  Abstract Perfluorinated compounds (PFCs) are a class of anthropogenic chemicals incorporated over six decades into a wide range of industrial and consumer-use products including surface treatments for carpets and textiles, paper and packaging, non-stick cookware, firefighting foams and insecticides. The extremely strong carbon-fluorine bond, "the strongest in organic chemistry", makes them thermally and chemically stable, and resistant to degradation. Several studies on toxicology of PFCs demonstrate negative health effects of these compounds. Some PFCs were added to the Stockholm convention on Persistent Organic Pollutants (POPs) in 2009, due to their persistence, toxicity, and widespread occurrence in the environment. Stainresistant carpets comprise a major part of global historical PFC production and use. Landfills are a major source of PFC emissions to the environment as final destinations for discarded consumer articles, including carpets. This thesis explores how various PFCs leach from carpets to landfill leachate, and how factors like temperature, pH and contacting efficiency affect the transfer of PFCs into aqueous media. Experiments were conducted in which a number of carpets manufactured in ~2000 to 2005 were contacted with landfill leachate and distilled water. Transfer of different PFCs into the aqueous phase increased with contacting time, with differences between 1 and 24 h much greater than between 24 and 168 h. A temperature increase from 5 to 35oC resulted in a significant increase in PFC leaching. Increasing the pH from 5 to 8 resulted in an increase followed by a decrease in leaching of most PFCs. The overall leaching rates of PFCAs into distilled water were somewhat greater than into landfill leachate. The majority of PFC exchange between carpets and leachate was more dependent on some factor (e.g. adsorption or desorption) rather than external mass transfer.  !  ii  Preface For all carpet and leachate samples in this study, sample extraction, clean-up and PFC analyses using LC/MS/MS were carried out at the Fisheries and Oceans Canada Institute of Ocean Sciences in Sidney, British Columbia by Dr. Jonathan Benskin, under the guidance of Dr. Michael Ikonomou.  !  iii  Table of Contents Abstract .........................................................................................................................................ii Preface ........................................................................................................................................ iii List of Tables ............................................................................................................................ viii List of Figures .............................................................................................................................. xi List of Abbreviations ................................................................................................................. xiv List of Chemicals ....................................................................................................................... xvi Acknowledgements ..................................................................................................................xvii Chapter 1: Introduction ................................................................................................................. 1 1.1 Problem statement............................................................................................................. 1 1.2 Objectives ......................................................................................................................... 4 1.3 Plan of this thesis .............................................................................................................. 4 1.4 Research contributions ...................................................................................................... 7 Chapter 2: Background and Literature Review ............................................................................ 8 2.1 Introduction and physical/chemical properties ................................................................. 8 2.2 Synthesis ......................................................................................................................... 13 2.3 Applications .................................................................................................................... 15 2.4 Toxicology and health effects ......................................................................................... 17 2.5 PFCs in Canada ............................................................................................................... 19 2.6 Sources and human exposure .......................................................................................... 21 2.7 Environmental fate and transport .................................................................................... 22 2.8 Perfluorinated compounds in carpets: from manufacturing to disposal ......................... 25 2.9 Leaching test procedures and factors affecting leaching rates........................................ 31  !  iv  Chapter 3: Materials and Methods.............................................................................................. 33 3.1 Introduction ..................................................................................................................... 33 3.2 Utilized materials ............................................................................................................ 34 3.2.1 Carpets..................................................................................................................... 34 3.2.2 High-pressure liquid chromatography (HPLC) grade water ................................... 34 3.3 Experimental set-up ........................................................................................................ 35 3.3.1 Bench-scale “end-over-end” contactor.................................................................... 35 3.3.2 Pilot-scale “end-over-end” contactor ...................................................................... 36 3.4 Experimental methodology ............................................................................................. 39 3.4.1 Carpet preparation ................................................................................................... 39 3.4.2 Leachate collection.................................................................................................. 41 3.4.3 Preliminary leaching experiments in the bench-scale “end-over-end contactor” ... 42 3.4.4 Final leaching experiments in the pilot-scale “end-over-end contactor” ................ 44 3.4.4.1 Effect of contact time .................................................................................... 47 3.4.4.2 Effect of rotation speed ................................................................................. 47 3.4.4.3 Effect of temperature..................................................................................... 47 3.4.4.4 Effect of pH .................................................................................................. 48 3.4.4.5 Individual carpets vs. composite ................................................................... 48 3.4.4.6 Contacting with distilled water ..................................................................... 49 3.5 Quality Assurance/Quality Control (QA/QC) procedures .............................................. 49 3.5.1 Leachate blank tests ................................................................................................ 49 3.5.2 Operational blank test ............................................................................................. 49 3.5.3 Base case experiments............................................................................................. 50 3.6 Carpet and leachate sample extraction (DFO-IOS) ........................................................ 50 !  v  3.6.1 Extraction of carpet samples ................................................................................... 50 3.6.2 Extraction of leachate samples ................................................................................ 52 3.7 Instrumental analysis (DFO-IOS) ................................................................................... 52 Chapter 4: Results and Discussion ............................................................................................. 56 4.1 Quality Assurance/Quality Control (QA/QC) ................................................................ 56 4.1.1 Leachate blank tests ................................................................................................ 56 4.1.2 Operational blank test ............................................................................................. 58 4.1.3 Base case experiments............................................................................................. 58 4.2 PFC concentrations in carpet samples ............................................................................ 60 4.3 Landfill leachate characterization ................................................................................... 63 4.4 Preliminary leaching experiments in bench-scale “end-over-end contactor” ................. 66 4.5 Final leaching experiments in pilot-scale “end-over-end contactor” .............................. 66 4.5.1 Mass conservation equations in leaching experiments ........................................... 66 4.5.2 Effect of contacting time on leaching rates ............................................................. 72 4.5.3 Effect of rotation speed on leaching rates ............................................................... 76 4.5.4 Effect of temperature on leaching rates................................................................... 78 4.5.5 Effect of pH on leaching rates ................................................................................. 85 4.5.6 Leaching rates of PFCs from samples of individual carpet compared to composite samples .................................................................................................................... 88 4.5.7 Leaching rates of PFCs to leachate compared to distilled water............................. 93 Chapter 5: Conclusions and Recommendations ....................................................................... 100 5.1 Conclusions ................................................................................................................... 100 5.2 Recommendations ......................................................................................................... 102 References ................................................................................................................................ 104  !  vi  Appendix A: Heat transfer between liquid in vessels and air ................................................... 117 Appendix B: Preliminary test results ........................................................................................ 121 Appendix C: Raw data and recoveries for carpet samples ....................................................... 125 Appendix D: Raw data, recoveries and characteristics of leachate samples ............................ 129  !  vii  List of Tables Table 2.1: PFCs analysed in this study (Giesy et al. 2010; OECD 2007) .................................. 10 Table 2.2: Properties of PFCs and their precursors .................................................................... 11 Table 2.3: Solubility and vapor pressure of perfluorinated carboxylic acids ............................. 12 Table 2.4: PFC exposure routes during usage of both mill-treated and spray-treated carpets ... 30 Table 2.5: Specifications of different landfill sites in Canada.................................................... 31 Table 3.1: Details of collected carpets ........................................................................................ 35 Table 3.2: Summary of leaching experiments conducted in pilot-scale contactor ..................... 45 Table 3.3: Leachate blank test conditions................................................................................... 50 Table 3.4: Method Detection Limits (MDLs) for different PFCs in leachate sample analysis .. 54 Table 3.5: Mass-labelled internal standards used in DFO-IOS lab ............................................ 55 Table 4.1: Concentrations of different PFCs in leachate blank samples for various test conditions.................................................................................................................................... 57 Table 4.2: Different PFC concentrations obtained for tests conducted under base-case conditions (time=6 h, pH=6, temperature=15oC and rotation speed=8 rpm). ............................ 59 Table 4.3: Mean, standard deviation and standard errors of PFC concentrations (all in ng/g) in carpet samples analysed in this study. ........................................................................................ 61 Table 4.4: Blank-corrected physical properties and chemical concentrations analysed for leachate immediately after collection and after 50 days of storage at 4oC. ................................ 64 Table 4.5: PFC concentrations in leachate. Mean values and standard deviations are calculated for each PFC.. ............................................................................................................................. 65  !  viii  Table 4.6: Net inputs and outputs of different perfluorinated compounds from carpet and leachate samples in six leaching tests. ........................................................................................ 68 Table 4.7: Mean PFC concentrations and their standard deviations in leachate samples after contacting with composite carpet samples at pH=6, temperature=15oC, rotation speed=8 rpm and certain contacting times. ...................................................................................................... 73 Table 4.8: Concentrations of remaining PFCs in composite carpet samples after 6 and 168 h contact with landfill leachate at pH=6, temperature=15oC and rotation speed=8 rpm............... 75 Table 4.9: Mean PFC concentrations and their standard deviations in leachate samples after contacting with composite carpet samples for 6 h at pH=6, temperature=15oC and varying rotation speeds (0, 4 and 8 rpm). ................................................................................................ 77 Table 4.10: Concentrations of PFCs leached from composite carpet samples to leachate at 5±1, 15±3 and 35±1oC, pH 6 and rotation speed 8 rpm for 2, 6 and 24 h contact time. ………80 Table 4.11: Mean and standard deviation of PFC concentrations (in ng/mL) in leachate after contacting with composite carpet samples at pH=6, temperature=15oC, rotation speed=8 rpm and solution pH of 5, 6, 7, and 8................................................................................................. 86 Table 4.12: PFC concentrations in leachate after contact with composite and individual carpets (N4, N5, N6, N7 and N8) at 15oC, pH 6 and rotation speed 8 rpm.. ............................................. 90 Table 4.13: PFC concentrations leached from composite carpet samples to both leachate and distilled water with pH of 5, 6, 7 and 8 after 6 h contact at temperature of 15oC and rotation speed of 8 rpm. ........................................................................................................................... 94 Table B.1: Preliminary tests - concentrations of different PFCs in leachate/distilled water after contacting with carpet fibre for 0.5, 1, 2, 4, 10, 24 and 72 h. ................................................... 122 Table B.2: Preliminary tests - concentrations of different PFCs in blank leachate samples after 0, 0.5, 24, and 72 h, at temperature of 21± 2oC, pH of 7.1 and rotation speed of 8 rpm. ......... 122 Table C.1: Raw data for carpet analysis for samples before and after contact with leachate or distilled water. Note that the experiments have been conducted in triplicate. ......................... 125 Table C.2: Recovery percentages for carpet samples before contact. ...................................... 128  !  ix  Table C.3: Efficiencies for extraction of different PFCs from carpet samples. ...................... 128 Table D.1: Recovery percentages for leachate samples. .......................................................... 129 Table D.2: Raw data for PFC amounts (ng) in leachate samples. Note that the sample IDs correspond to those introduced in Table D.1 (N.D. stands for non-detectable). ...................... 132 Table D.3: Initial and final pH, total dissolved solids (TDS) and electrical conductivity of leachate samples of different leaching experiments. ................................................................ 135 !  !  x  List of Figures Figure 1.1: Research plan ............................................................................................................. 6 Figure 2.1: Structure of PFCs and some of their precursors (adapted from Giesy et al. 2006).... 8 Figure 2.2: An example of an electrochemical fluorination process .......................................... 14 Figure 2.3: Key aspects of the electrochemical fluorination (right) and telomerization (left) processes ..................................................................................................................................... 15 Figure 2.4: Overview of significant points of PFC emissions from carpet manufacturing to end-of-life ................................................................................................................................... 29 Figure 3.1: Overall work flow of leaching experiments ............................................................. 33 Figure 3.2: Bench-scale “end-over-end contactor” .................................................................... 36 Figure 3.3: Pilot-scale “end-over-end contactor” ....................................................................... 37 Figure 3.4: (a) Plan-view of a single vessel and (b) side-view of pilot-scale end-over-end contactor (all dimensions are in mm) ......................................................................................... 38 Figure 3.5: Flowchart of final experiments ................................................................................ 39 Figure 3.6: Schematic of carpet mixing method (i.e. quartering) ............................................... 40 Figure 3.7: 100 g of composite carpet sample after preparation ................................................ 41 Figure 4.1: Concentrations of different PFCs in blank leachate after 6 h and 168 h at pH of 6, temperature of 15oC and rotation speed of 8 rpm ....................................................................... 58 Figure 4.2: Percentages by mass of each PFC in total PFCs present in raw leachate. Compounds along horizontal axis are in order of increasing number of carbon atoms for both PFCAs and PFSAs. ..................................................................................................................... 65 Figure 4.3: Net output PFC amounts vs. net input PFC amounts (presented in Table 4.6)... .... 70  !  xi  Figure 4.4: Concentrations of (a) PFBA, PFPA, PFHxA, PFHpA, PFOA (b) PFNA, PFDA, PFUnA, PFDoA, PFTA, (c) PFHxS, and PFOS in leachate samples after contacting with composite carpet samples at pH=6, temperature=15oC, rotation speed=8 rpm versus contact time.. ........................................................................................................................................... 74 Figure 4.5: Total PFC concentrations in leachate samples after contacting with composite carpet samples at pH=6, temperature=15oC and rotation speed=8 rpm, versus contact time .... 75 Figure 4.6: PFC concentrations in leachate samples after contacting with composite carpet samples for 6 h at pH=6, temperature=15oC and rotation speed of (a) 8 vs. 0 rpm, (b) 4 vs. 8 rpm and (c) 8 vs. 4 rpm. ............................................................................................................. 78 Figure 4.7: Concentrations of PFCAs in landfill leachate after contact with composite carpet for (a), (b) 2 h and (c), (d) 6 h vs. (1/T), where T is absolute temperature................................. 81 Figure 4.8: Leaching rates of PFTA from composite carpet samples to leachate at 5, 15 and 35oC after 2, 6 and 24 h contact time. ........................................................................................ 84 Figure 4.9: Leaching rates of (a) PFHxS and (b) PFOS from composite carpet to landfill leachate at 5, 15 and 35oC for 2, 6 and 24 h contact time. ......................................................... 85 Figure 4.10: Total concentrations of PFCAs and PFCs in leachate after contacting with composite carpet samples at pH=6, temperature=15oC, rotation speed=8 rpm and solution pH of 5, 6, 7, and 8. .......................................................................................................................... 87 Figure 4.11: Concentrations of different PFCs leached from composite carpet samples to leachate after 6 h contact time at temperature=15oC, rotation speed=8rpm and pH of 5, 6, 7, and 8…….… .............................................................................................................................. 88 Figure 4.12: “Experimental” vs. “Expected” PFCA leaching rates from composite carpet samples to landfill leachate at temperature 15oC, pH 6 and rotation speed 8 rpm. Parity line is shown to aid comparison. ........................................................................................................... 91 Figure 4.13: Percentage of initial PFCAs on different carpets appearing in landfill leachate after 6 h contact at pH 6, temperature 15oC and rotation speed 8 rpm. ...................................... 92 Figure 4.14: PFCA concentrations in distilled water versus blank-corrected PFCA concentrations in landfill leachate after 6 h contact with composite carpet samples at 15oC, rotation speed of 8 rpm and (a) pH=5, (b) pH=6, (c) pH=7, (d) pH=8. ..................................... 96  !  xii  Figure 4.15: PFCA concentrations in distilled water and blank-corrected landfill leachate after 6 h contact with composite carpet samples at 15oC, rotation speed of 8 rpm and (a) pH=5, (b) pH=6, (c) pH=7 and (d) pH=8 .................................................................................................... 98 Figure 4.16: (a) PFHxS and (b) PFOS concentrations in distilled water and blank-corrected landfill leachate after 6 h contact with composite carpet samples at 15oC, rotation speed of 8 rpm and solution pH of 5, 6, 7 and 8. ......................................................................................... 99 Figure A.1: Side-view of a single vessel .................................................................................. 118 Figure B.1: Concentrations of different PFCAs in leachate after contacting with carpet fibre for 0.5, 1, 2, 4, 10, 24 and 72 h.. ............................................................................................... 123 Figure B.2: Summation of PFCAs in leachate after contacting with carpet fibre for 0.5, 1, 2, 4, 10, 24 and 72 h. .................................................................................................................... 123 Figure B.3: Comparison of PFCA concentrations in blank-corrected landfill leachate and distilled water after 3 days of contact with carpet fibre at temperature of 21± 2oC, pH of 7.1 and rotation speed of 8 rpm. ..................................................................................................... 124 !  !  xiii  List of Abbreviations AFFF  aqueous fire fighting foam  BC  British Columbia  CEPA  Canadian Environmental Protection Agency  DFO-IOS  Fisheries and Oceans Canada Institute of Ocean Sciences  ECF  electrochemical fluorination  EPA  United States Environmental Protection Agency  FTCA  fluorotelomer carboxylic acid  FTUA  fluorotelomer unsaturated acid HDPE  HDPE  high density polyethylene  HPLC  high pressure liquid chromatography  IDL  instrument detection limit  LC/MS/MS  liquid chromatography-tandem mass spectrometry  MDL  method detection limit  MSW  municipal solid waste  PFC  perfluorinated compound  PFCA  perfluorocarboxylic acid  PFSA  perfluorosulfonate  POP  persistent organic pollutant  R2  Pearson's correlation coefficient  rpm  revolutions per minute  TCLP  toxicity characteristic leaching procedure  TDS  total dissolved solids  TOC  total organic carbon  !  xiv  UBC  University of British Columbia  WTP  water treatment plant  WWTP  wastewater treatment plant  !  xv  List of Chemicals 6:2 FTOH  6:2 fluorotelomer alcohol  8:2 FTOH  8:2 fluorotelomer alcohol  10:2 FTOH  10:2 fluorotelomer alcohol  N-EtFOSE  n-Methyl perfluorooctane sulfonamido ethanol  N-MeFOSE  n-Ethyl perfluorooctane sulfonamido ethanol  PFBA  perfluorobutanoic acid  PFBS  perfluorobutane sulfonate  PFDA  perfluorodecanoic acid  PFDoA  perfluoroundecanoic acid  PFDS  perfluorodecane sulfonate  PFHpA  perfluoroheptanoic acid  PFHxA  perfluorohexanoic acid  PFHxS  perfluorohexane sulfonate  PFNA  perfluorononanoic acid  PFOA  perfluorooctanoic acid  PFOS  perfluorooctane sulfonate  PFOSA  perfluorooctane sulfonamide  PFPA  perfluoropentanoic acid  PFTA  perfluorotetradecanoic acid  PFUnA  perfluoroundecanoic acid  POSF!  perfluorooctanesulfonyl fluoride!  !  xvi  Acknowledgements Dr. Loretta Li and Dr. John Grace, my knowledgeable research supervisors: I express my sincere gratitude and appreciation for your guidance, support, and encouragement throughout my entire Master’s journey. This dissertation would not have been possible without all your eternal patience, brilliant judgement and valuable advice, which inspired and motivated me from the very early stages of this research. Dr. Michael Ikonomou, Dr. Jonathan Benskin, and the staff of the Fisheries and Oceans Institute of Ocean Sciences (DFO-IOS): I owe my deepest gratitude to you for your knowledgeable advice, providing laboratory assistance, and all your support for my research chemical analyses. This thesis would have remained a dream had it not been for your patience in answering my many questions over emails about PFCs and analytical chemistry in my entire Master’s program. Dr. Gilles Hebrard: It gives me immense pleasure to acknowledge you for being there whenever I needed you. From carpet preparation and leachate collection for my experiments to providing advice for writing heat transfer and mass balance equations for my thesis, you were always helping me with a cheerful attitude. Honestly, this research would not have become reality if it were not for your invaluable advice, exceptional suggestions, encouragement and patience. Mark Rigolo, Paula Parkinson, Timothy Ma, Bill Leung, Harald Schrempp and the staff of the UBC Civil Environmental Engineering Lab and Workshop: I consider it an honor to work with you. Thank you for your time and effort for not only providing the necessary equipment for this research, but also making the Environmental Laboratory a convivial place to work.  !  xvii  Without your constructive comments, laboratory assistance, and practical knowledge, I could not have done any part of this ambitious research. The landfill operator: I extend my sincere appreciation to you, although I could not mention your name. Thank you for your assistance collecting huge amounts of leachate from your landfill. All my wonderful friends and colleagues: A very special and heartfelt thanks to all my friends whose unconditional friendship and faith gave me such a pleasant time while working at UBC. My parents: Your unconditional and unwavering support, endless love and dedication from across the miles inspired and motivated me in my darkest hours of this research. Thank you for your support and believing in me for my whole life. I also would like to show my deepest gratitude to NSERC (Natural Sciences and Engineering Research Council of Canada) and to the Fisheries and Oceans Institute of Ocean Sciences (DFO-IOS) for providing financial support for this research.  !  xviii  Chapter 1: Introduction 1.1  Problem statement  Perfluorinated compounds (PFCs) are a class of anthropogenic chemicals consisting of a fluorinated alkyl chain (4-14 carbons), with various functional groups attached (Corsini et al. 2012). Although PFCs include thousands of chemicals (Lindstrom et al. 2011), they are best known for two classes of substances, perfluorosulfonates (PFSA) and perfluorocarboxylic acids (PFCAs). These are degradation products or manufacturing residuals of fluorinated polymers and PFC precursors integrated into many consumer products (Giesy and Kannan 2002). Several unique physical and chemical properties such as water and stain repellency, thermal stability, and surfactant properties are imparted by the strong fluorine-carbon bond in these compounds (Kissa 2001). PFCs have been incorporated into a wide range of industrial and consumer-use products including paper and packaging, non-stick cookware, surface treatments for carpets and textiles, firefighting foams, floor polishes, and insecticides for the past six decades (Prevedouros et al. 2006; 3M Company 1999a; Paul et al. 2009). The same properties that make the PFCs industrially beneficial also tend to make them accumulative and persistent environmental contaminants (Stock et al. 2004). In recent years, detection of individual PFCs of very low concentrations (i.e. in range of ppb) has become possible through significant advances in analytical chemistry and application of high-performance liquid chromatography tandem mass spectrometry (Hansen et al. 2001; Sottani et al. 2002). This improvement has made it possible to detect even trace levels of PFCs, which are ubiquitous in environmental matrices including surface water, groundwater,  !  1  indoor and outdoor air, soil, sediment, wildlife, and human blood sera, even in remote locations (Ahrens et al. 2011; Paul et al. 2009; Olsen et al. 2005; Giesy and Kannan 2001). Several studies on toxicology and health effects of PFCs demonstrate negative health effects such as weight loss, increased liver weight, decreased thyroid hormone levels, and altered sex hormones in laboratory species and humans (Kennedy et al. 2004; Seacat et al. 2003). Due to their persistence, toxicity, and widespread occurrence in the environment, PFOS, its salts, and perfluorooctane sulfonyl fluoride (PFOSF) were added to Annex B of the Stockholm convention on Persistent Organic Pollutants (POPs) in May 2009, resulting in global restrictions on the application and production of these compounds (Stockholm Convention 2009; Karrman et al. 2006; Lindstrom et al. 2011). In Canada, the manufacture and exportation of PFOS-related compounds (except for limited applications) has been discontinued since 2002 (Canada Gazette part I 2006). Emissions of PFCs to the environment occur through direct and indirect means. Direct PFC releases (e.g. from PFC manufacturing facilities) comprise the majority of emissions (~9599% of total emissions), while indirect sources (e.g. from PFC residuals or degradation of precursors in consumer products) comprise small contributions (Russell et al. 2008; Prevedouros et al. 2006). Landfills are one of the point sources of PFC emissions to the environment as they are the final destination for many fluorochemicals widely incorporated in consumer articles. These PFCs might remain in the landfills for decades or more. Most current landfills are equipped with leachate collection systems. Leachate is then treated on-site or directed to a wastewater treatment plant (WWTP). Conventional treatment processes in a WWTP do not appear to influence the concentrations of PFCs contained in landfill leachate (Huset et al. 2008).  !  2  In a case study by Schultz et al. (2006) on 10 WWTPs, even higher concentrations of a few PFCs were observed in the effluent due to possible biodegradation of precursors. In addition, PFCs might be sorbed to bio-solids and sewage sludge in the WWTPs (Higgins et al. 2005) and return to landfills for disposal. Between 1970 and 2002, stain-resistant carpets comprised approximately 50% of global historical PFC production and use (Paul et al. 2009). In Canada, 57.8% of total PFCs were applied to fabric and carpets between 1997 and 2000 (Footitt et al. 2004). Carpet treatments may be applied by fiber manufacturers and carpet mills, or by customers after purchasing carpets. It has been estimated that nearly 53% of the PFCs applied as carpet treatments remain at the disposal time on average (3M Company 1999a). The most common disposal method for carpets at the end of their useful lives in many countries is landfilling. In Canada, more than 90% of discarded commercial and residential carpets were landfilled in 2010 (Canadian Carpet Recovery Effort 2010). After being landfilled, the PFCs in carpets may leach into the landfill leachate. Considerable research has been carried out to determine the PFC concentrations in biota and environmental matrices, and to assess the associated health risks. In recent years, a few studies have aimed to document the concentrations of PFCs in different landfill sites in Canada (Li et al., 2012), the United States (Huset et al. 2011), Germany (Busch et al. 2010), and Denmark (Kallenborn et al. 2004). In addition, concentrations of PFCs in different consumer products have been reported in several articles (Begley et al. 2005; Sinclair et al. 2007; Fiedler et al. 2010; Guo et al. 2009; Washburn et al. 2005). However, no studies have been published about how PFCs leach from consumer products to landfill leachates and enter the environment. Residential and commercial carpets are disposed in landfills, and PFCs,  !  3  even those no longer being manufactured, will continuously enter the environment in future years, making it crucial to understand how the PFCs in carpets leach into landfill leachate.  1.2  Objectives  The overall objective of this thesis is to comprehensively study the leaching of different polyand per-fluorinated compounds from discarded carpets into landfill leachate and to shed light on how these materials behave in landfills. Specific objectives of this study were: •  To determine the levels and types of PFCs and their precursors in old and new carpets;  •  To characterize and measure PFC concentrations of leachate from a landfill in western Canada;  •  To determine the leaching extent and leaching rate of different PFCs from used and unused carpets to landfill leachate;  •  To study the effect of changes in contact time, contacting efficiency, temperature and pH on leaching rates of different PFCs to landfill leachate and/or distilled water; and  •  To investigate if the rate of leaching of PFCs from carpets to landfill leachate is externally mass-transfer controlled.  1.3  Plan of this thesis  Chapter 2 provides a review of the chemical and physical properties of the compounds of interest, their manufacture, applications and environmental factors, and specifies their incorporation in, and leaching from, carpets. In order to achieve the objectives listed in the previous section, a number of leaching experiments were conducted, in which used and unused carpets were contacted with landfill leachate. To determine the leaching extent and leaching rate of different PFCs, carpet samples  !  4  were contacted with leachate for specific time periods under controlled pH and temperature conditions. In order to investigate the effect of different factors on PFC leaching rates, experiments were carried out at pH between 5 and 8, temperature between 5 and 35oC and varying contacting conditions. In addition to contacting carpet samples with leachate, a number of experiments were designed to contact carpets with distilled water, allowing PFC leaching rates to be determined in the absence of other agents, e.g. organic and inorganic matter, which may contribute to leaching. The experiments were conducted in two levels of preliminary tests and final tests. Since no previous data about leaching rates of PFCs were available in the literature, preliminary tests were included to provide an overview of the PFC leaching rates and of PFC expected levels in the aqueous media after contact with PFC-containing compounds. For more details about the leaching test procedures, see Chapter 3. The experimental results are presented in Chapter 4, and conclusions and recommendations in Chapter 5. Straight-chain perfluoroalkyl carboxylic acids (PFCAs) of 4 to 12 and 14 carbon atoms and straight-chain perfluoroalkyl sulfonates of 4, 6, 8, and 10 carbons were studied in this thesis. In addition to these PFCs, perfluorooctane sulfonamide (FOSA), an 8-carbon-length fluorinated sulfonamide was analysed. Figure 1.1 presents a flowchart of the research plan, including the tasks designed to realize the objectives of this study. The various steps in the tests are described in detail in Chapter 3, with results then appearing in Chapter 4.  !  5  Figure 1.1: Research plan  !  6  1.4  Research contributions  This study is intended to clarify the leaching extents and rates of different perfluorinated compounds and their precursors from waste materials to landfill leachate. The results are intended to contribute to a comprehensive understanding of whether or not PFC-containing waste could have a significant effect on leachate quality. In addition, the study sheds light on the parameters (e.g. pH and temperature) influencing the leaching of PFCs from waste, and ultimately to groundwater. These results would provide further information for regulators helpful in developing best management practices. This could aid in making decisions about more appropriate ways for disposal of PFC-containing waste and regulation of PFCs in consumer products to benefit both the environment and public health.  !  7  Chapter 2: Background and Literature Review 2.1  Introduction and physical/chemical properties  Poly- and per-fluorinated compounds involve a heterogeneous class of chemicals consisting of a fluorinated alkyl chain (4–14 carbons), with various functional groups attached (Corsini et al. 2012). In poly-fluorinated hydrocarbons, hydrogen atoms are replaced by fluorine atoms in multiple sites (e.g., telomer alcohols); while in perfluorinated species all of the hydrogen atoms are replaced by fluorine atoms (e.g., PFOS and PFOA) (Lindstrom et al. 2011). Figure 2.1 shows the chemical structures of two classes of PFCs and their precursors. Note that the perfluorinated carboxylic acids are expected to dissociate in the environment almost entirely to their anionic forms. Perfluorinated Compounds (PFCs)  Perfluorooctane sulfonate (PFOS)  Perfluorooctanoate (PFO-)  PFC Precursors  Perfluorooctyl sulfonamide R=CH2CH3, CH2CH2OH, CH2OH or H  Fluorotelomer Alcohol (FTOH) (x=3, 4, 7, 9 etc.)  Figure 2.1: Structure of PFCs and some of their precursors (adapted from Giesy et al. 2006)  !  8  PFCs are mostly comprised of a hydrophilic head of sulfonates or carboxylates and a hydrophobic tail of fluorinated carbon chain (Bhhatarai and Gramatica, 2011). Polyfluorinated sulfonamidoethanols (FOSEs) and telomer alcohols (FTOHs) are broadly used to incorporate perfluorinated alkyl groups into various polymeric materials. (NMeFOSE) and (N-EtFOSE) are two major sulfonamides incorporated into numerous fluoropolymers. The FTOHs are usually referred to as X:Y FTOH, with X showing the perfluorinated carbon atoms and Y representing non-substituted methylene groups. These compounds have elicited considerable attention recently since they are suspected to be precursors of (PFOS) and longer-chain PFCAs (Lei et al. 2004). Table 2.1 represents names, acronyms, Chemical Abstracts Services (CAS) numbers, chemical structures and molecular weights of different classes of PFCs of direct interest in this study. Most of the unique physical and chemical properties of PFCs are due to the extremely strong Carbon-Fluorine bond, labelled as "the strongest in organic chemistry" (O’Hagan 2008), with a Bond Dissociation Energy (BDE) of up to 544 kJ/mol (Lemal 2004). This strong bond is resistant to heat, strong acids and bases, oxidizing and reducing agents, photolysis, microbes, and metabolic processes (Schultz et al. 2003; Kissa 2001). Unfortunately, there is currently little information on the chemical-physical properties of most PFCs since their properties change with varying physical and chemical conditions. Experimental studies on physical/chemical properties of poly- and per- fluorinated compounds mainly focus on PFC precursors rather than PFSAs and PFCAs. Table 2.2 shows empirical results for vapor pressure and solubility of various PFC precursors from different studies. Differences between similar values are mostly due to different analytical methods and test conditions.  !  9  Table 2.1: PFCs analysed in this study (Giesy et al. 2010; OECD 2007) Group  Perfluoroalkyl Sulfonate  Compound name  Acronym  CAS No.  Molecular structure  Molecular wt. (g/mol)  Perfluorobutane sulfonate  PFBS  375-73-5  C4F9SO3H  300  Perfluorohexane sulfonate  PFHxS  355-46-4  C6F13 SO3H  400  Perfluorooctane sulfonate  PFOS  1763-23-1  C8F17 SO3H  500  Perfluorodecane sulfonate  PFDS  335-77-3  C10F21 SO3H  600  Perfluorobutanoic acid  PFBA  375-22-4  C3F7COOH  214  Perfluoropentanoic acid  PFPA  2706-90-3  C4F9COOH  264  Perfluorohexanoic acid  PFHxA  307-24-4  C5F11COOH  314  Perfluoroheptanoic acid  PFHpA  6130-43-4  C6F13COOH  364  Perfluorooctanoic acid  PFOA  335-67-1  C7F15COOH  414  Perfluorononanoic acid  PFNA  375-95-1  C8F17COOH  464  Perfluorodecanoic acid  PFDA  335-76-2  C9F19COOH  514  Perfluoroundecanoic acid  PFUnA  2058-94-8  C10F21COOH  564  Perfluorododecanoic acid  PFDoA  307-55-1  C11F23COOH  614  Perfluorotetradecanoic acid  PFTA  376-06-7  C13F27COOH  714  Perfluorooctane sulfonamide  FOSA  754-91-6  C8F17SO2NH2  499  Perfluoroalkyl Carboxylic Acid  Fluoroalkyl Sulfonamide  !  10  Table 2.2: Properties of PFCs and their precursors. Compound Name  PFOA  Perfluorooctanoic acid  C7F15COOH 335-67-1  4.2 7.0  Potassium perfluorooctane sulfonate  C8F17 SO3K 68391-09-3  0.0003 (20oC) (3M Company 2000a)  4:2 Fluorotelomer alcohol  CF3(CF2)3C2H4OH 2043-47-2  990 (25oC) (Dinglasan et al. 2004) 992 (25oC) (Stock et al. 2004) 1670 (25oC) (Lei et al. 2004)  6:2 Fluorotelomer alcohol  CF3(CF2)5C2H4OH 647-42-7  713 876  (25oC) (Stock et al. 2004) (25oC) (Lei et al. 2004)  2.93 3 227 254 270 53 140 144  (25oC) (Hekster et al. 2002) (21oC) (Kaiser et al. 2004) (25oC) (Lei et al. 2004) (25oC) (Stock et al. 2004) (25oC) (Dinglasan et al. 2004) (25oC) (Lei et al. 2004) (25oC) (Dinglasan et al. 2004) (25oC) (Stock et al. 2004)  PFOS, K  +  4:2 FTOH 6:2 FTOH  CF3(CF2)7C2H4OH 678-39-7  10:2 FTOH 10:2 Fluorotelomer alcohol  CF3(CF2)9C2H4OH 865-86-1  n-MeFOSE  n-Methyl perfluorooctane sulfonamido ethanol  n-EtFOSE  n-Ethyl perfluorooctane sulfonamido ethanol  Vapor Pressure (Pa)  CAS No.  8:2 Fluorotelomer alcohol  8:2 FTOH  !  Molecular Structure  Acronym  C8F17SO2N(CH3)C2H4O H 24448-09-7 C8F17SO2N(C2H5)C2H4 OH 1691-99-2  Solubility (mg/L)  (25oC) (Prevedouros et al. 2006) 9.5 (25oC) (Hekster et al. 2002) (25oC) (Hekster et al. 2002) 680 (25oC) (Ellefson 2001) 570 (25oC) (3M Company 2000a) 974  (22oC) (Liu and Lee 2007)  18.8 (22oC) (Liu and Lee 2007) 12-17 (25oC) (Hekster et al. 2002) 0.137 (21oC) (Kaiser et al. 2004) 0.14 (25oC) (Hekster et al. 2002) 0.006-0.885 (22oC) (Liu and Lee 2007)  0.002 (23oC) (Shoeib et al. 2004) 0.7 (25oC) (Lei et al. 2004)  N/A  0.009 (23oC) (Shoeib et al. 2004) 0.35 (25oC) (Lei et al. 2004)  0.151 (25oC) (Hekster et al. 2002)  11  From Table 2.2, it appears that the water solubilities of fluorotelomer alcohols are relatively low. Typically, the major structural feature influencing water solubility of fluorotelomer alcohols is the fluorocarbon chain length; higher chain length fluorotelomer alcohols have lower solubility (Liu and Lee 2007). The vapor pressures of fluorotelomer alcohols are usually higher than those of their parent alcohols; for example, 10:2 FTOH is 1000 times more volatile than dodecanol (Stock et al. 2004). Properties of most sulfonates and carboxylic acids are not yet available, even though knowledge of the physical and chemical properties of PFCs is crucial to study their environmental fate and transport, in particular their leachability in landfills. In order to fill this gap for PFC properties, software packages are utilized to estimate these properties and to give insight into understand the relative behavior of these compounds. Table 2.3 shows the solubility and vapor pressure of various carboxylic acids predicted by models based on theoretical molecular descriptors (Bhhatarai and Gramatica 2011). Table 2.3: Solubility and vapor pressure of perfluorinated carboxylic acids (adapted from Bhhatarai and Gramatica 2011). Name PFBA PFPA PFHxA PFHpA PFOA PFNA PFDA PFUnA PFDoA  !  Solubility (mg/L) 446.7 120.2 29.5 6.6 1.7 0.2 0.0 0.0 7.6x10-5  Vapor Pressure (Pa) 131.8 338.8 120.2 39.0 12.0 3.5 1.0 0.3 0.1  12  The vapor pressure of perfluorinated carboxylic acids decreases with increasing fluorocarbon chain length (Kaiser et al. 2005). The acids and their free salts are reasonably soluble in water and insoluble in lipids. Increasing the chain length decreases the aqueous solubility of these acids (Kaiser et al. 2006).  2.2  Synthesis  Two major manufacturing processes are adopted to produce fluorinated compounds: electrochemical fluorination (ECF) and telomerization (Kissa 2001). The former was established by Simons in 1944. 3M Company, the major manufacturer of POSF-based chemicals up to 2002, used this route after 1956 (3M Company 1950). In the ECF process, all hydrogen atoms of a straight chain hydrocarbon are substituted with fluorine atoms as a result of electricity-promoted reaction with hydrogen fluoride (Kissa 2001). The major target compound in this process is perfluorooctane sulfonyl fluoride (POSF). The ECF is a relatively impure process, leading to approximately 35-40% straight chain POSF, with the remainder being a mixture of branched and cyclic isomers, primarily from 4 to 9 carbons, as byproducts. The POSF product is used in a series of reactions to produce N-methyl and N-ethyl perfluorooctane sulfonamidoethanol (N-MeFOSE andN-EtFOSE), with historical applications in producing surface coatings for textiles and paper products (Paul et al. 2009; Olsen et al. 2005). An example of the ECF process is illustrated in Figure 2.2. Note that all compounds produced from POSF have the potential to degrade or transform to PFOS ultimately; therefore these materials may be considered to be “PFOS equivalents” (Lindstrom et al. 2011). From 1947 through 2002, most (80-90% in 2000) ammonium perfluorooctanoate (APFO) worldwide was manufactured through the ECF process (Prevedouros et al. 2006).  !  13  Figure 2.2: An example of an electrochemical fluorination process (adapted from Hekster et al. 2003). Haszeldine developed another method for producing perfluorinated compounds in 1964 (DuPont Company 1964; Rao and Baker 1994). This method, called Telomerization, was adopted first by the DuPont Company in the 1969s, and it has been used by AsahiGlass, AtoFina, Clariant, Daikin, and DuPont Companies since then (Hekster et al. 2003). In this process, fluorinated chemicals are produced by iterative reaction of perfluoroethyl iodide (telogen) with perfluoroethylene (taxogen), yielding perfluoroalkyl chains, which differ in length by CF2 CF2 (D’eon and Mabury 2011). The transfer of iodine produces a mixture of linear perfluorinated iodides (Paul et al. 2009). Reaction with ethylene yields fluorotelomer iodides (x:2 FTI), which can produce fluorotelomer alcohols (X:Y FTOH) after being hydrolyzed (D’eon and Mabury 2011). Unlike the ECF process, telomerization products are linear process compounds, containing a small percentage of branched products (Kissa 2001). Note that the final fluorinated polymers produced through both ECF and telomerization usually contain unreacted or partially reacted starting materials or intermediates, which end up in the final products (Olsen et al. 2005). Figure 2.3 presents the major characteristics of the ECF and telomerization processes for manufacturing perfluorinated compounds.  !  14  Telomerization  Electrochemical Fluorination (ECF)  Linear fluorocarbon chain  35-40% linear n-POSF  Even numbered chain length  Even and odd numbered chain lengths  6,8,10,12, and 14 carbon chain length  4 and up carbon chain lengths  Manufacturers: Dupont, Asahi glass, Daikin, Clariant  Manufacturers: 3M, Bayer, Miteni, etc. Now!used!for!PFBS/based! products!  Figure 2.3: Key aspects of the electrochemical fluorination (right) and telomerization (left) processes.  2.3  Applications  Poly- and perfluorinated compounds have been incorporated into a wide range of industrial and consumer products for the past six decades due to their unique physical and chemical properties. The major commercial applications of PFCs fall into these groups (3M Company 1999a; Prevedouros et al. 2006; Washburn et al. 2005): •  Surface treatments,  •  Paper and packaging protectors, and  •  Performance chemicals.  Surface treatments provide soil, water, and stain resistance to residential and commercial furnishings and apparel, lowering the surface energy of the material to which they are applied and significantly increasing the useful lifetime and sustaining the appearance of carpets,  !  15  fabric, leather and upholstery. The PFCs in surface treatment chemicals are primarily manufactured as high-molecular-weight polymers (mostly with a perfluorinated chain length of 8 carbons) and could be either N-MeFOSE or fluorotelomer based (D’eon and Mabury 2011). In 2004, Dupont (2004) announced that the major portion of its fluorotelomer-based commercial products (~80%) were fluorinated polymers applied as surface treatments, while only 20% were used as fluorosurfactants. Paper and packaging protectors are applied by paper mills and packaging manufacturers to food packaging and papers to improve their moisture and oil barrier properties. The phosphate esters of N-EtFOSE alcohol, acrylate copolymers of N-MeFOSE (3M Company 1999a), or low molecular weight mixtures of C6, C8, C10, and C12 flurotelomers are commonly used in the production of these chemicals (Begley et al. 2005). Performance chemicals are typically low-molecular-weight surface-active monomers (3M Company 1999a), preferentially with a perfluorinated chain length of six carbons (D’eon and Mabury 2011). These compounds could be used either directly in consumer products or as intermediates in manufacturing finished products. Fluorochemical surfactants normally result in surface tensions as low as 15-16 dynes/cm at concentrations of 100 ppm or less, making them suitable for applications in the mining and oil industries, carpet spot cleaners, insecticide raw materials, metal plating, and household additives (e.g. floor polishes). Besides surface tension reduction, some POSF-based performance chemicals have the ability to form tough and resilient foams, useful for production of Aqueous Fire Fighting Foams (AFFFs) to resist the action of high temperature or aggressive chemicals and vapors (3M Company 1999a,b). In addition to various fluorinated polymers, PFCs have direct commercial applications. PFOS can be incorporated in AFFFs, hydraulic fluids, and photolithography (OECD 2002; Paul et  !  16  al. 2009). No direct application of PFOA in commercial products has been reported; however the ammonium salts of PFOA are an essential processing aid in manufacturing of PTFE, the functional component of non-stick pans (D’eon and Mabury 2011; Prevedouros et al. 2006) and to a lesser extent in industrial applications in the electronic industry and as an anti-static additives (OECD 2002). Note that since PFOA degrades at the high temperatures applied in cookware manufacturing, non-stick pans do not contain any detectable PFOA (Washburn et al. 2005).  2.4  Toxicology and health effects  Several research studies have been conducted recently on the toxicological effects of PFCs and their concentrations in humans and wildlife. It is well known that both PFOA and PFOS can be easily absorbed orally; however it takes a long time for them to be eliminated or degraded in the human body, as well as in wildlife (Johnson et al. 1984; Kemper and Nabb 2005). Although the elimination rates of PFCs vary significantly among species (Olsen et al. 2005) and even between genders of a specific species (Kemper and Jepson 2003), the elimination potential decreases with increasing fluorinated carbon chain length (Lau et al. 2007). PFCs are highly bio-accumulative in humans and wildlife. Approaches for studying PFC bioaccumulation differ totally from those used to study other fat-soluble persistent organic pollutants; because PFCs have a high tendency to bind to protein albumin (Rayne et al. 2009; Kelly et al. 2009). This is why greater concentrations of PFCs have been observed in proteinrich tissues, specifically liver, kidney and blood serum (to a lesser extent) in both monitoring and laboratory studies (Quinete et al. 2009; Hundley et al. 2006; Seacat et al. 2002,2003). The bioaccumulation potential of PFCs depends greatly on the carbon chain length, as well as on  !  17  the attached functional group. Long-chain PFCAs and PFSAs have the highest bioaccumulation potential, with perfluorinated sulfonates more likely to accumulate than perfluorinated carboxylates of the same length (Martin et al. 2003). For example, the bioaccumulation rate of PFOA has been observed to be 20 times lower than for PFOS (Liu et al. 2011). Greater concentrations of PFCs in animals high in a food chain (i.e. top predators) compared with those in their diets provide strong evidence for bioaccumulation and biomagnification of PFCs (Giesy and Kannan 2001; Houde et al. 2006; Tomy et al. 2004). The trends for biomagnification potential in PFCs are similar to those for bioaccumulation; the highest biomagnifications have been observed for PFNA to PFUnA, as well as PFOS (Kelly et al. 2007; Houde et al. 2006). The potential toxicities of PFOS and PFOA in monkeys (Seacat et al. 2002), rats (Austin et al. 2003; Seacat et al. 2003), fish (Hoff et al. 2005; Martin et al. 2003), and humans (Olsen et al. 1999, 2003) have been widely characterized in recent years; however, less is known about the toxicology of PFCs of carbon chain lengths other than C-8 perfluorochemicals, (Lau et al. 2007). Early responses to exposure to PFOA and PFOS are reported to include reduced body weight, increased liver weight, and serum cholesterol and thyroid hormones reduction in experimental animals (Kennedy et al. 2004; Seacat et al. 2003). Studies examining hormone levels in workers reported an increase in serum estradiol levels among individuals with the highest PFOA serum levels (Olsen et al. 1998). A significant inverse association of serum PFOA concentrations with birth weight and birth length has been reported in Denmark (Fei et al. 2008). Notably increased diabetes mortality in occupationally exposed groups compared with non-exposed workers has also been observed (Lundin et al. 2009). Melzer et al. (2010)  !  18  reported a statistical increase in Odds Ratio (OR) of having thyroid disease in women with elevated blood PFOA concentrations. In addition, PFOA and PFOS are known to affect the immune system (White et al. 2011). In general, the toxicity behavior of PFCs follows similar trends as bioaccumulation; PFOS and its derivatives are more toxic than PFOA, and toxicity of PFCs increases with chain length (Jensen et al. 2008). Furthermore, linear PFCs show higher toxicities than their branched analogues (Kawashima et al. 1995). Studying the PFC levels in human blood sera has revealed some findings about general PFC exposure. A strong correlation between blood concentrations of PFOA and PFOS implies that similarities exist between human exposure pathways to these compounds (Apelberg et al. 2007). In addition, after 3M’s phase-out of the production of POSF-based compounds, a 60% decrease in PFOS concentrations and a 25% drop in PFOA concentrations were observed in blood samples collected in the United States over the 2000-2006 period (Olsen et al. 2008).  2.5  PFCs in Canada  Prior to 2002, most PFOS-based compounds in Canada were imported as raw chemicals and as components in products, formulations and manufactured items. The manufacture and exportation of these compounds was discontinued in 2002 (Canada Gazette part I 2006). The total amount of PFCs imported into Canada from 1997 to 2000 was estimated to be 600 tonnes, with PFOS-based substances comprising 43% of imported PFC compounds. As in many other countries, the main applications of these substances were as surface treatments, providing water, oil, soil and grease repellency for fabric, leather, paper and packaging, carpets and rugs, as well as AFFFs, and paint and coatings additives. Footitt et al. (2004) estimated the percentage of total fluorochemicals tonnages used for different applications in !  19  Canada between 1997 and 2000. Based on their study, 57.8% of total PFCs were used in fabric and carpets, 28.9% in paper and packaging products, 6% in AFFF products, and the remainder in other areas (e.g. processing aids, leather protection and polymer additives). The use of PFOS-based compounds in Canada dropped sharply after 2000, when the major global manufacturer of perfluorinated sulfonamides voluntarily phased-out of the manufacture of PFOS-based compounds. The only permitted applications of PFCs in Canada now are in metal plating, photography and photolithography, semiconductor industries, hydraulic fluids, papers and printing plates and, while current stocks last, PFOS-based AFFFs (Canada Gazette part II 2008). Although PFOS-based substances have not been manufactured in Canada since 2002 and importing them is limited to specific applications, there is a growing concern associated with increasing imports from Asia, especially in apparel products, since these may be a potential source of PFCs. Canada was the first government to ban three fluoropolymer stain repellents containing telomer alcohols in December 2004 (Renner et al. 2005). In addition, in July 2006, the ministers of the Environment and Health proposed to add PFOS and its salts to the List of Toxic Substances in Schedule 1 of the Canadian Environmental Protection Agency (CEPA) 1999 Act. Their final decision was published on the screening assessment of PFOS in the Canada Gazette, Part I, and (Canada Gazette part II 2008). On April 17th, 2008, the PFOS Virtual Elimination Act received Royal Assent and became law. The objective was to demonstrate the Government’s continuing commitment to virtually eliminate PFOS and to meet the requirements of the CEPA 1999 Act (Government of Canada 2009).  !  20  2.6  Sources and human exposure  PFC emission sources can be classified as direct and indirect sources. Direct sources include all environmental emissions resulting from PFC and polymer manufacturing, AFFF products, and consumer products in which the perfluorinated compounds and their derivatives are used. Indirect emissions might result from release of the PFCs in consumer products as unwanted manufacturing residuals, or degradation of POSF-based and fluorotelomer-based products, as well as fluorinated polymers (Prevedouros et al. 2006).  The concentration of the  fluorochemical residuals in commercial products is typically less than 1% (Olsen et al. 2005) and might include PFHxS, PFOSA, N-MePFOSE, and N-EtPFOSE in sulfonamide-based products, and PFOA and other perfluorinated carboxylic acids in telomere-based products (Parsons et al. 2008). Direct PFC releases comprise the majority of emissions, while indirect sources contribute little (Russell et al. 2008). The total emissions of PFCAs from 1951 to 2004 have been estimated to be between 3200 and 7300 tonnes, with indirect sources accounting for ~1-5% of the total (Prevedouros et al. 2006). Uncertainty exists in the assessment of indirect sources due to the complexity of the degradation mechanism for fluorinated polymers incorporated into commercial products and for fluorotelomer alcohols and perfluorinated sulfonamides contained as residuals in these substances (Myers et al. 2010). Degradation mechanisms of these compounds are considered in the next section. Human exposure might occur through the following mechanisms (Shoeib et al. 2011), which are similar to environmental emissions.  !  •  Directly from manufacturing and use of PFOA and PFOS in commercial products;  •  Atmospheric oxidation and breakdown of precursors that degrade to PFOS and PFOA;  •  Absorption of the precursors into the body and their metabolic transformation. 21  The main pathways of human exposure to PFOS, PFOA and their precursors include diet and drinking water (Vestegren and Cousins 2009), air inhalation, dust ingestion (Shoeib et al. 2011) and absorption from dermal contact (Fasano et al. 2006).  2.7  Environmental fate and transport  The strength of the carbon-fluorine bond is the key contributor to the unique physical and chemical properties of PFCs; however, it appears to be the major factor in restraining the biodegradability of PFCs. In general, perfluorinated compounds are more resistant to biodegradation than poly-fluorinated compounds. While neither PFOS nor PFOA show any aerobic biodegradation (Parsons et al. 2008), several recent investigations for determination of the environmental fate of FTOHs and perfluorinated sulfonamides have shown potential degradation pathways by which these compounds end up as PFCAs and PFSAs in the environment. Atmospheric oxidation (Ellis et al. 2004) and aerobic biodegradation, e.g. detected in microbial cultures (Dinglasan et al. 2004; Wang et al. 2005), liver tissues (Martin et al. 2005; Nabb et al. 2007) and rat models (Fasano et al. 2006) are considered the key PFC degradation pathways. The most important final product of FTOH transformation is a PFCA shorter by two carbon units than the parent FTOH (Dinglasan et al. 2004); low conversions (1-10%) are observed in activated sludge, mixed bacterial cultures, and mammalian metabolism, while higher conversions (up to 40%) could be obtained in aerobic soil samples (Wang et al. 2009). In addition to PFOA, the FTCAs and FTUCAs are two known intermediates in biodegradation of FTOH to PFCAs in all studies. Due to the somewhat shorter lifetimes of FTCAs in the environment, the FTUCAs are normally expected to be observed in environmental samples (Myers et al. 2010). Rapid biodegradation of 6:2 FTOH, the second dominant FTOH in fluorinated polymer products, occurs in both aerobic soils and  !  22  mixed bacterial culture with a degradation half-life of less than 2 days (Liu et al. 2010). Note that both even and odd chain length PFCAs are produced in biodegradation of FTOHs to PFCAs, although PFCAs resulting from the telomerization process comprise only even chain length PFCs (Liu et al. 2010). In the case of POSF-based precursors, N-EtFOSA, FOSA and FOSAA were formed in the first day as biodegradation products of N-EtFOSE in activated sludge, while PFOS appeared as the final degradation compound after 3 days (Rhoads et al. 2008). Unlike fluorotelomers and POSF-based precursors, few studies have been carried out to investigate the biodegradation of fluorinated polymers, the main active ingredients in manufacturing of commercialized products. In the environment, these polymers undergo sequential transformation to their poly-fluorinated components, and ultimately to PFCAs. However, a recent study by Van Zelm et al. (2008) has been reported that the emissions from fluoroacrylate polymers, one of the most important classes of PFCs in surface treatment products (3M Company 1999a; Rao et al. 1994), currently comprise a minor fraction of total PFOA emissions. Thus, degradation of the residuals in the polymeric products is the chief contributor to PFOA generated from fluorotelomer acrylate production and use. Note that the residual amounts of 8:2 FTOH and PFOA in the fluorotelomer acrylate polymers are typically 0.5 and 0.013% by weight respectively (Russell et al. 2008). Furthermore, hydrolysis of Fluoroacrylate polymer does not break down the ester linkage at pH of 4, 7 or 9 at 50oC (Dupont Company 2004). In urban areas, the presence of PFCs in food (Begley at al. 2005; Young et al. 2012; Fromme et al. 2009; Domingo 2012), air (Shoeib et al. 2004; Fraser et al. 2012; Shoeib et al. 2011), house dust (Liu et al. 2011; Shoeib et al. 2005), and drinking water (Skutlarek et al. 2006;  !  23  Lange et al. 2007) has been widely reported in the literature. In addition, PFCs have been studied in rivers, lakes and oceans worldwide have been studied. Typically high PFC concentrations are observed in regions with direct industrial emissions, since they have an impact on fresh water lakes and rivers, with concentrations ranging from 1-1000s ng/L (Saito et al. 2004; Skutlarek et al. 2006; Nakayama et al. 2010). In oceans, the concentrations of perfluorinated acids are approximately three orders of magnitude lower than in lakes and rivers (Yamashita et al. 2005). Trace levels of PFOA (N.D.-11.3 µg/L) and (0.3-7.5 µg/kg) have been detected in Canadian fresh water and fresh water sediments respectively (Environment Canada 2010). These findings are in agreement with negligible concentrations of PFOA and PFOS (i.e. 0.2 ng/L and N.D., respectively) detected in Vancouver and Calgary (Fuji et al. 2007). PFCs are ubiquitous in humans (Kannan et al. 2004), with much higher concentrations in occupationally exposed workers (Ehresman et al. 2007). In addition, PFCs occur widely in biota, especially in fish (Bossi et al. 2005), aquatic invertebrates (Kannan et al. 2001), fisheating birds (Kannan et al. 2001) and marine mammals (Houde et al. 2006; Butt et al. 2007). Moreover, fluorochemicals are detected widely in mammals, birds, and several other species, found only in remote regions (Paul et al. 2009; Olsen et al. 2005). Wastewater treatment plants (WWTPs) are a major point source for PFCs to the environment. Conventional WWTPs are not effective for removing PFCs; hence similar or even higher PFC concentrations have been reported in the effluent of WWTP in comparison to the influent (Huset et al. 2008; Schultz et al. 2006). The biotransformation of precursor compounds within the WWTP might be the chief contributor to increase concentrations of PFCAs and PFSAs in the influent. In the effluent from Canadian WWTP facilities, the concentration of PFOA  !  24  ranges from 0.007 to 0.055 µg/L (Environment Canada 2010). Landfills also play a critical role in the release of PFCs to soil, air, surface water and groundwater, as they are the final destination for many fluorochemicals used in consumer articles. Release of PFCs to the environment depends highly on the concentration of remaining PFCs at disposal time, landfilling practices and leachate collection systems. Leachates containing PFOS and PFOA are normally sent to municipal treatment facilities after collection; however, since these compounds are not removed from the influent of these facilities, they either pass directly into the downstream aquatic environment, or are contained in bio-solids, which are whether applied directly onto land or returned to the originating landfills (Environment Canada 2006). In a study on leachate samples from seven municipal landfills in the United States (Huset et al. 2011), PFCAs were the dominant compounds (~67%) in leachate, followed by PFSAs (~22%), perfluoroalkyl sulfonamides (~8%), and fluorotelomer sulfonates (~2.4%). Emissions to air also occur in municipal landfills due to volatilization of precursors contained in disposed compounds, or water-air transfer of watersoluble PFCs that have readily transferred to landfill leachate. In a recent study by Ahrens et al. (2011), FTOHs have been reported to be the major class (~93-98% of the ΣPFCs), with dominance of the even chain-length PFCAs in air for two solid waste landfill sites in Ontario. However, in the same study, PFOS contributed ~2% of the total emissions, possibly due to partitioning to landfill leachate, or strong sorption to landfill solids.  2.8  Perfluorinated compounds in carpets: from manufacturing to disposal  For over half a century, fluorinated compounds have been incorporated into carpet finishing treatments to provide stain resistance (Kissa 2001). The carpet treatments are applied by fiber manufacturers, carpet mills, and customers as post-application treatments under trade names  !  25  like Scotchgard® (from the 3M company), Teflon® Advance, Zonyl®, and Stainmaster® (from Dupont company), which are readily available at hardware and carpet retail stores. The primary “active ingredients” in carpet and textile treatments (e.g. ScotchGard and Stainmaster) are fluorinated polymers. Dupont’s carpet protector is typically a mixture containing both urethane and acrylic FTOH based copolymers (Dupont Company 2001). Scotchgard carpet protector contains a mixture of fluoroalkyl copolymers as well as other acrylic based polymers (3M Company 2003). The 3M carpet protection products contain approximately 15% fluoroalkyl polymers (Hekster et al. 2002). Upon application, these compounds are adsorbed or chemically bound to the treated textile. Figure 2.4 presents an overview of the significant points of contact where PFCs are used in carpets. Note that the flowchart describes the typical carpet product line, and not every product necessarily goes through all steps. The total environmental releases through the life cycle of a stain resistant carpet can be studied in three stages: •  Carpet treatment, •  Carpet mills and fiber manufacturers  •  Application of spray cans  •  Customer usage, and  •  Disposal.  Carpet mills and fiber manufacturers: Typically 0.05-0.5% by weight of fluorochemical is added to carpets to provide long-lasting repellency (Rao et al. 1994). Initial application of surface treatment products to uncut carpet or fiber through several methods including spray, foam, pad, or co-application might end up as PFC losses to air and wastewater. Furthermore, !  26  throughout shearing, cutting and other packaging operations, solid wastes are generated, which finally end up in landfills.  In addition to carpet and fiber manufacturers, PFC  treatments might be applied by professional carpet steam cleaners, showing similar wear patterns to mill-applied treatments (3M Company 1999a). Application of spray can products: Environmental releases during the application of these products depend on the size and shape of the carpet and accuracy of the applicator. The 3M Company estimated that the transfer efficiency across all sizes and shapes was ~66%; therefore 34% of the PFCs are initially released to air, with a potential for deposition (3M Company 2000b). In addition to losses during application, approximately 12.5% of the original spray contents remain in the can at the time of disposal; since a small percentage of these cans are recycled or incinerated, spray products represent a significant potential source of PFC release to landfills. Customer usage: Substantial release (up to 50%) of the flurochemical treatment is expected during the estimated nine-year average life of a carpet due to traffic and vacuuming (3M Company 2000b), with the release ending up in air and landfills. In a recent Japanese study (Liu et al. 2011), PFCAs were widely detected in vacuum cleaner dust samples, with the oddnumbered long-chain PFCAs (e.g. PFNA, PFUnDA, and PFTrDA) as the major components. PFC losses to wastewater treatment plants and possibly landfills (i.e. as biosolids) are also expected from steam cleaning. Table 2.4 presents PFC exposure routes during usage of both mill-treated and spray-treated carpets. Tittlemier et al. (2007) identified treated carpeting as the second major contributor to daily intake of PFCAs and PFOS after ingestion of food in a typical Canadian house. Disposal: On average, more than half (53%) of PFCs initially applied as carpet treatments  !  27  remain at the disposal time (3M 2000b). At this stage, used carpets are either incinerated or sent to landfills. During incineration, both acrylate polymer and other PFC residuals are completely destroyed (Yamada et al. 2005); however, in Canada, municipal incineration of solid waste represents approximately 5% of total solid waste disposal (Environment Canada 2006) and accounts for less than 10% of residential and commercial carpet removal in 2010 (Canadian Carpet Disposal Fact Sheet 2010). Degradation conditions in landfills extensively vary in temperature, as well as in available oxygen and moisture levels (Russell et al. 2008). Fluoropolymers have a negligible chance of degradation in the short term, since the biodegradation half-life of Fluoroacrylate polymer in aerobic soils has been estimated to be 1200-1700 years (Russell et al. 2008). Note that although the perfluoroacrylate polymers are not a significant source of emissions, they remain in landfill soils for long periods and possibly become the major emission source of PFCs after the phase-out of global PFC production (Van Zelm et al. 2008). The main releases from landfilled carpets to the environment are through residual PFCAs, PFSAs, or FTOH-based and sulfonamide-based precursors brought about by incomplete synthesis or lack of purification prior to marketing (Dinglasan et al. 2006). In a study by Dinglasan et al. (2006), free NMeFOSE was observed in a Scotchgard® carpet and rug protector manufactured pre-2002, while unbound telomer alcohols with chain lengths from 8 to 14 carbons (6:2 up to 12:2 FTOHs) were detected in a Teflon® Advance product. The extent of unbound residual PFOS, n-methyl and n-ethyl FOSA and N-MeFOSE and N-Et FOSE alcohols in 3M products is up to 1-2% (3M 1999a). For fluorotelomer acrylate, 0.5% by weight of 8:2 FTOH and 0.013% by weight of PFOA are normal in consumer products (Russell et al. 2008).  !  28  Figure 2.4: Overview of significant points of PFC emissions from carpet manufacturing to end-of-life.  !  29  Table 2.4: PFC exposure routes during usage of both mill-treated and spray-treated carpets (Source: Washburn et al. 2005) Article Group Mill treated carpet Solution treated carpet  Dermal contact  Ingestion via handmouth contact  Incidental ingestion of dust  Inhalation of particulates  Inhalation of vapor  Ingestion of contacted food  Inhalation of droplets  Yes  Yes  Yes  Yes  Yes  Yes  No  Yes  Yes  Yes  Yes  Yes  Yes  Yes  Due to high vapor pressure and low water solubility of the PFC precursors, the residual telomer or sulfonamide alcohols in carpets preferentially partition into air during the carpet life (Lei et al. 2004). Sulfonamide alcohols have a higher chance of remaining in the carpet surface in old carpets, since their vapor pressures are approximately 3 orders of magnitude lower than for FTOHs. The vapor pressures of precursor residuals are so high that most of them volatilize during the drying process in carpet mills (Buck et al. 2005). Therefore, the only compounds expected to mostly end up in the landfills from old carpets are residual PFCAs and PFSAs, which have low vapor pressures. Since these compounds are quite water soluble, transfer from old carpets to landfill leachate is very likely. The total annual amounts of PFC emissions to landfill leachates can be calculated by multiplying the average concentration of PFCs in leachate samples, which might have seasonal variations (Li et al. 2012), by the annual leachate flow. Table 2.5 shows the annual leachate flows, served populations, and total waste quantities from three different landfills in Canada.  !  30  Table 2.5: Landfill specifications of different landfill sites in Canada Landfill name and location  Leachate flow (m3/year)  Year  Population served  Total landfilled waste (tonnes)  Hope landfill, BC 1  107,000  2009  7,840  6,746  Vancouver landfill, BC 2  2,080,000  2011  1,060,000  1,299,279  Eastview landfill, ON (closed in 2003) 3  120,000  2010  Not available  No waste  1  From Hope Landfill 2009 Annual Report (2011)  2  From Vancouver Landfill 2010 Annual Report (2011)  3  From Eastview Road Landfill Site 2010 Annual Report (2011)  2.9  Leaching test procedures and factors affecting leaching rates  Although no studies have been published about leaching of PFCs from carpets into landfill leachate at this point, several experiments have been carried out on mechanisms of leaching of other compounds, most of which following directly the procedures of Toxicity Characteristic Leaching Procedure (TCLP) under the EPA SW846 Method 1311 (1992) (US EPA 2009). The TCLP method simulates contaminant leaching in MSW landfills, using a solution of acetic acid as an extraction fluid. Acetic acid is produced in landfills during anaerobic decomposition of waste. In addition to TCLP, other standards e.g. Synthetic Precipitation Leaching Procedure (SPLP) EPA Method 1312 (1994) and California’s Waste Extraction Test (WET) (1985) (US EPA 2009) are widely used in leaching studies (Townsend et al. 2004; Lincoln et al. 2007). Care must be taken while using different standard procedures since the composition of extraction fluids in different test methods might not always represent what is encountered in actual landfill conditions. For example, Jang and Townsend (2003) reported a dramatic difference between concentrations of leached lead using the TCLP  !  31  method and those measured using real landfill leachate. Real landfill leachate is preferred to simulated extraction fluids in batch leaching tests to provide more realistic landfill conditions. Many different factors such as waste type, analyte concentration is waste, solution pH and ionic strength, leaching test solid wt./liquid wt. ratio, samples size and contact time might have an impact on leaching amounts and rates (Townsend et al. 2004). For instance, noticeable increases in leachability of lead were reported at both low and high pH values, while minimum leachability was witnessed at neutral pH (Townsend et al. 2004). In addition to these factors, temperature is expected to alter the leaching rates of PFCs, whether by affecting the solubility of different PFCs (Bhhatarai and Gramatica 2011) or influencing the bacterial activity (Wang et al. 2008).  !  32  Chapter 3: Materials and Methods 3.1  Introduction  This chapter describes the experimental equipment, procedures, and analysis used to study the transfer of PFCs from carpets to aqueous media. All leaching experiments were conducted in bench- and pilot-scale “end-over-end” contactors. Figure 3.1 provides an overall flowchart of these experiments.  Figure 3.1: Overall work flow of the leaching experiments  !  33  3.2  Utilized materials  3.2.1 Carpets Carpet samples were the main constituent in all leaching experiments. A number of used and new carpets were collected from suppliers in Vancouver, thrift stores, and departments of UBC. Table 3.1 summarizes the approximate date of manufacture, appearance, fibre thickness, location of usage, and possible previous treatment types for each of the collected carpets. Carpets N1, N2, and N3 were not selected for this study due to their negligible concentrations of PFCs. Details of the PFC concentrations in each carpet sample are described in Section 4. The extraction and analysis methods for different PFCs are described in Sections 3.6 and 3.7 below. 3.2.2 High-pressure liquid chromatography (HPLC) grade water HPLC grade water was used in the experiments to minimize the level of contamination. The suspended solids of tap water were first removed by pre-filtration. A Barnstead Thermolyne (Model A1013-B) water still was then used to evaporation and condensate the pre-filtered water. The distilled water was then collected in two 45 L high density polyethylene (HDPE) bottles and fed to a Synergy UV Millipore system. Finally, ultrapure HPLC grade water with resistance of 18.2 MΩ.cm at 25oC and pH of 7.65 was obtained from the UBC Department of Civil Engineering.  !  34  Table 3.1: Details of collected carpets No.  Source  Approximate Date of Manufacture  Physical conditions  Fibre thickness (mm)  N1  Carpet retailer  2011  Brand new, unused  20  Treatment by Scotchgard at carpet mill  N2  Carpet retailer  2011  Brand new, unused  10  Treatment of fibre by Dupont products (Stainmaster)  2011  Brand new, unused  10  Treatment of fibre by Dupont products (Stainmaster) “Highly stain resistant” on the label, one of the very recent products  2005  Maintained in boxes in the warehouseunused  10  Treatment of carpet through a heatand-force actuated cohesion process – Contains high MW polymers – no further info provided  10  Treatment of carpet through a heatand-force actuated cohesion process – Contains high MW polymers – no further info provided  N3  Carpet retailer  N4  Commercial carpet used in UBC CHBE building when it was opened.  N5  Used in UBC Pulp and Paper Centre when some offices were upgraded.  ~2000  N6  Thrift store  N/A, ~2000  N7  Thrift store  N/A, ~2000  N8  Commercial collected by UBC APSC  N/A  3.3  Maintained in boxes in the warehouseunused and clean Contains heavy dust- used conditions Contains heavy dust- used conditions Unused and clean  15  15  10  Previous treatments  Unknown, possible treatment by mills, steam cleaners, or aerosol sprays Unknown, possible treatment by mills, steam cleaners, or aerosol sprays Unknown, possible treatment by carpet mill or fibre manufacturer  Experimental set-up  3.3.1 Bench-scale “end-over-end contactor” Preliminary tests were carried out in the initial experiments in a small Dayton bench-scale “end-over-end contactor” model 5X412. This contacting apparatus, shown in Figure 3.2, holds 12 x 500 mL HDPE bottles and rotates at rotation rates from 0 to 25 revolution(s) per minute. The rotation speed was set to 8 rpm during the preliminary tests. The HDPE bottles  !  35  were rinsed with methanol and air-dried prior to the experiments to remove possible PFC contamination.  Figure 3.2: Bench-scale “end-over-end contactor” 3.3.2 Pilot-scale “end-over-end contactor” The results from preliminary leaching tests allowed the conditions for the final tests to be chosen in a more effective way. Details of the analysis are provided in Section 3.7. All final experiments were conducted in the custom-built “pilot-scale end-over-end contactor”, shown in Figure 3.3. Details of the design and operation of this facility are given by Danon-Schaffer (2010). This contacting device included 5 parallel cylindrical vessels, each simultaneously contacting carpets with leachate, in most cases, at a rotational speed of 8 revolutions per minute (rpm). !  36  Rotation promoted contact between carpet and leachate by creating turbulence and forcing liquid to flow through the pieces of carpet. The rotation speed was changed by a transformer changing the input voltage to the electric motor as required. The contactor was built and assembled by the UBC Department of Chemical and Biological Engineering workshop in 2005. Each vessel has an inner diameter of 82 mm and an inside length of 900 mm, providing a capacity of ~ 5 L for each vessel. More details about the rotator are provided in Figure 3.4.  Figure 3.3: Pilot-scale “end-over-end contactor”  !  37  A 1-inch (25 mm) ball valve is located at the bottom of each vessel for sub-sampling. All  components of the apparatus were fabricated from food-grade stainless steel to minimize adsorption of PFCs onto the vessel walls.  (a)  (b)  Figure 3.4: (a) Plan-view of a single vessel and (b) side-view of pilot-scale end-over-end contactor (all dimensions are in mm). Unlike the preliminary tests, whole pieces of carpet (i.e. fibres attached to their backings) were utilized for the final tests, better representing what is encountered in real landfill situations. Figure 3.5 provides a flow chart of the final leaching experiments. Altogether this included 30 contacting tests carried out in duplicate.  !  38  Figure 3.5: Flowchart of final experiments  3.4  Experimental methodology  3.4.1 Carpet preparation Particle size is one of the most important factors affecting leaching rates (Townsend et al. 2004). In preliminary tests, where only carpet fibres were utilized, carpet fibres was simply separated from the attached backings. The separated carpet fibres were then mixed thoroughly by hand to improve the homogeneity of the matrix. In the final tests, where carpet fibres were not separated from backings, carpet samples were cut with a Microtop industrial cutting machine into 20 x 20 mm squares in order to maintain the consistency in all experiments. In order to examine more realistic conditions where several carpets might enter the landfill at the same time, composite carpet samples were tested in some contacting experiments. Nitrile gloves were employed to handle carpet samples. To ensure homogeneity of the carpet !  39  samples, a method similar to quartering (split sampling) was used to thoroughly mix the carpet pieces, with this method applied separately for each carpet type (i.e. N4, N5, N6, N7, and N8). The steps to mix and prepare carpet samples were as follows: a. On a clean surface, all carpet pieces were divided into quarters and the contents of each quarter were mixed thoroughly. Care was taken to ensure that the surface was not contaminated with PFCs. b. Two quarters were then mixed together to form halves. c. The two halves were then combined and blended to form a more homogeneous matrix. This procedure was repeated 10 times for each type of carpet. Figure 3.6 shows a schematic of the quartering method.  Figure 3.6: Schematic of carpet mixing method (i.e. quartering). Thereafter, 100 g composites of N4, N5, N6, N7 (22.5 wt. % each), and N8 (10 wt. %) were weighed, mixed, and stored in clean plastic bags, which did not contain any PFCs. The proportions where chosen based on the availability of each carpet. In addition to composites, 2 x 100 g of each individual carpet were also stored in plastic bags. Figure 3.7 shows a photo of a composite carpet sample.  !  40  Figure 3.7: 100 g of composite carpet sample after preparation. 3.4.2 Leachate collection The leachate was collected by the author on Jan 30th, 2012 from an urban landfill in Canada1, which accepted municipal waste as well as residuals and sludge from WWTPs and Water Treatment Plants (WTPs). The landfill was equipped with a double ditch leachate collection system, where the inner ditch collected the leachate and the outer one water. The leachate was pumped to a WWTP for treatment. Prior to sampling, 20 L HDPE carboys were rinsed first with HPLC grade water followed by methanol and air-dried afterwards. Nitrile gloves were used for sample handling. Approximately 270 L of leachate was collected from the landfill’s leachate well using a bailer and transferred to the carboys. In order to minimize any changes in leachate quality as a result of biological activity or evaporation of volatile precursors, samples were shipped to the UBC  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 1!The identity of the landfill cannot be disclosed because of a confidentiality agreement with the landfill operator.! !  41  Department of Civil Engineering immediately after collection and stored in a 4 - 6oC walk-in fridge. The leachate was characterized for pH, conductivity and Total Dissolved Solids (TDS) by the author before being stored in the fridge. A ϕ 44 Beckman pH meter (Model PHI 44) was used for the pH measurements. Prior to each use, the instrument was calibrated using buffer solutions with pH of 4, 7 and 10. For conductivity and TDS measurement, a PioNneer 30 portable conductivity meter was used, which was calibrated with a KCl standard with a known electric conductivity prior to each use. The fresh leachate was also preserved and characterized for Total Organic Carbon (TOC) and total metals including Al, As, Be, Ca, Fe, Mg and Zn. by the UBC Environmental Engineering Laboratory. The EPA Standard Methods 5310B (2000) and 3120 (1999) were followed to characterize the TOC and total metals of the leachate respectively (US EPA 2009). 3.4.3 Preliminary leaching experiments in the bench-scale “end-over-end contactor” The main objective of the preliminary tests was to determine the leaching of PFCs from carpet to leachate and distilled water at different contact times. Carpet N5, an unused carpet with an approximate manufacture date of 2000, was used for the preliminary tests. Analysis of a sample of this carpet prior to the leaching experiments demonstrated high concentrations of PFCs (~543 ng of ΣPFCAs per g of carpet) in this carpet. Detailed information on the analysis methods is provided in Section 3.7. In the preliminary tests, the carpet backings were separated from the fibres, and only the fibres were utilized. The leachate was collected by Li (2011) from a landfill2 serving a large urban area. This leachate had been stored in a 15 L !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! The identity of the landfill cannot be disclosed because of a confidentiality agreement with the landfill operator.! 2!  !  42  HDPE carboy since being collected in August 2010 at -20oC to prevent changes in the PFC concentrations. Storing at this temperature is one the most appropriate ways of PFC sample preservation (Leeuwen et al. 2007), stopping bacterial activity causing biodegradation and preventing losses from evaporation of volatile PFCs, e.g. sulfonamides. Two days prior to starting, the frozen leachate was removed from the fridge to thaw at room temperature (21oC). During the preliminary experiments, the carboy was stored in a 4 - 6oC walk-in fridge. 400 mL aliquots of leachate were collected in 500mL HDPE bottles after shaking the carboys thoroughly by hand for 30 s. Before introducing carpet samples to the leachate, the bottles were left in the room for 2 h in order to reach room temperature. Otherwise, the creation of a temperature profile might impact the results. Carpet samples were next added to the bottles with a solid/liquid (w/w) ratio of 1:20 and placed in the contactor, rotating at a speed of 8 rpm. The carpet-leachate contact times ranged from 0.5 h to 3 days. Since the leaching rates were expected to decrease as time passed (because of a decrease in concentration gradient), shorter sampling time intervals were chosen at the beginning of experiments than the end. Due to the high cost of analysis, only 2 experiments were carried out in triplicate. All preliminary tests were conducted at 21± 2oC. In addition to leaching of PFCs from carpets to the leachate, the biodegradation of precursors of the leachate was a possible contributor to the increase in PFC concentration in the leachate. Therefore, 10 experiments were conducted to monitor possible changes of PFC concentrations in landfill leachate at various time intervals from 0.5 h to 3 days. At the end of each run, a 45 mL aliquot of each sample was passed through a 200 µm stainless steel mesh and collected in a 50 mL polypropylene centrifuge tube. The mesh had been washed with methanol and air-dried prior to each test to prevent from contamination. It  !  43  successfully separated the floating carpet fibres from the liquid. The pH, electrical conductivity and total dissolved solids of the leachate were then measured and recorded. The tubes were filled up to 90% of their total volume, leaving a 5 mL headspace to prevent cracking the tubes due to expansion of their contents while stored in fridge at -20oC. The samples were shipped to the Department of Fisheries and Oceans Canada Institute of Ocean Sciences (DFO-IOS) in Sidney, BC in coolers packed with ice for extraction and analysis. 3.4.4 Final leaching experiments in the pilot-scale “end-over-end contactor” The leaching tests conducted in the pilot-scale “end-over-end contactor” followed a method similar to the EPA Toxicity Characteristic Leaching Procedure (TCLP), described in Section 2.9. Table 3.2 summarizes the leaching experiments carried out in the pilot-scale end-overend rotating apparatus. In each experiment, 100 g of composite or individual carpet was cut, mixed (as explained in section 3.4.1) and added to each vessel, together with 4 L of leachate or distilled water. A headspace of ~20% of the total vessel volume (i.e. ~1 L) was provided in each test. The solid/liquid ratio (wt./wt.) was 1:40 in all tests. The results from the preliminary tests implied that higher solid/liquid ratios might need dilution for the analysis, while lower values might have led to concentrations below the limit for detection of some PFCs.  !  44  Table 3.2: Summary of leaching experiments conducted in pilot-scale end-over-end contactor. Type of Experiment  Effect of contact time Effect of rotation speed Effect of pH  Contact with distilled water  Individual carpets vs. composite  Effect of temperature 1  Contact time (h)  pH  Wt. liq./ wt. carpet  1 2 6 24 168 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 2 24 6 2 24  6 6 6 6 6 6 6 6 5 7 8 6 5 6 7 8 6 6 6 6 6 6 6 6 6 6 6 6  40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40  Carpet  Liquid  Composite Composite 1 Composite 1 Composite 1 Composite 1 Composite 1 Composite 1 Composite 1 Composite 1 Composite 1 Composite 1 Composite 1 Composite 1 Composite 1 Composite 1 Composite N4 N5 N6 N7 N8 1 Composite 1 Composite 1 Composite 1 Composite 1 Composite 1 Composite 1 Composite  Leachate Leachate Leachate Leachate Leachate Leachate Leachate Leachate Leachate Leachate Leachate Leachate Water Water Water Water Leachate Leachate Leachate Leachate Leachate Leachate Leachate Leachate Leachate Leachate Leachate Leachate  1 1  Rotation speed (rpm) 8 8 8 8 8 0 4 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8  Average temperature (oC) 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 5 5 5 35 35 35  Mixture of carpet samples, including 22.5 (wt. %) each of N4, N5, N6, N7, and 10 (wt.%) of N8.  In order to explore the effect of pH, temperature and rotation speed on PFC leaching rates, a base condition was set for the experiments, and all conditions were varied around the corresponding specific value. The base condition included:  !  •  Contact time: 6 h,  •  pH: 6, one of the most common pH values for landfill leachates,  •  Temperature: room temperature (~15 ± 3oC), 45  •  Rotation speed: 8 revolutions per minute,  •  Solid/liquid mass ratio: 1:40,  •  Carpet type: Composite.  Prior to starting each test, a leachate carboy was taken out of the fridge and shaken thoroughly by hand for 30 s to obtain a homogeneous matrix. Precisely 4 L of leachate was then transferred to a 5L HDPE container, which had previously been rinsed in order by hot water and soap, HPLC water, and methanol, then air-dried. The initial pH of the collected leachate was ~7. Glacial acetic acid, an organic acid formed during the anaerobic decomposition of organic compounds in landfills, was applied to the leachate to reduce the pH to 6 ± 0.05. Pure glacial acetic acid (99.7%) from Fisher Scientific was first diluted with HPLC grade water to obtain a diluted solution of 10% acetic acid. This diluted solution was then used to reduce the pH of 1L leachate sample by trial and error through a method similar to titration. Approximately 3.5 mL of diluted acetic acid were required to reduce the leachate pH from 7 to 6, so that ~15 mL of diluted acetic acid was added to 4L of leachate. The pH was measured and recorded next to ensure a pH of 6±0.05. The electrical conductivity and TDS were also recorded. The container was then left for 2 hours to reach room temperature before transferring the leachate to the “end-over-end contactor” vessels through a HDPE funnel, which had previously been rinsed with methanol and then air-dried. The temperature of the room in which the experiments were conducted was subject to fluctuations throughout the tests. When the doors were opened in winter, sudden temperature drops (down to ~8oC) were witnessed. Despite the extent of these changes, the leaching rates were not affected significantly as long as these changes did not have a noticeable intermediate-term effect on the mean temperature of room, which was 15±3oC for the majority of tests. This is because of  !  46  a time lag between changes in temperature of the ambient air and the temperature of the aqueous media due to the heat transfer resistance and thermal inertia, mainly from the steel walls of the vessels. See Appendix A an analysis of the time lag and energy balance equations for this system. The experiments summarized in Table 3.2 are discussed below. Note that at the end of all leaching tests, 45 mL aliquots of corresponding samples were collected and stored following the same procedure as discussed in Section 3.3.1. 3.4.4.1  Effect of contact time  Composite carpets were contacted with leachate samples separately for 0.5, 1, 2, 6, 24, and 168 h, each in duplicate. This range of contact times was chosen based on the preliminary test results in which the concentrations of most PFCs appeared to approach their asymptotic values after 3 days of contact. As discussed previously, the time intervals between sampling at the beginning of the tests were shorter than towards the end. These experiments were carried out at room temperature with a rotation speed of 8 rpm. 3.4.4.2 Effect of rotation speed It is assumed that the rotation provides enhanced contact between the carpet particles and aqueous media; this assumption was verified by conducting tests with three different rotation speeds: 0 (static), 4, and 8 rpm. These tests were carried out at the base case conditions, except that the rotation speed was varied. 3.4.4.3 Effect of temperature To explore the effect of temperature on leaching rates of various PFCs and their precursors, 100 g of composite carpet sample was contacted with 4L landfill leachate over a temperature  !  47  range of 5-35oC, covering the temperature range of most municipal solid waste (MSW) landfills. The upper limit indicates the generation of heat as a result of waste oxidation. Due to the high cost of analysis, the leaching experiments were conducted at two temperatures: 5±1, and 35±1oC. The temperature was maintained during the period of experiments by placing the contactor at a walk-in temperature chamber at the UBC Environmental Engineering Laboratory. The contactor was placed in the chamber 14-15 h prior to each test so that all vessels reached the desired temperature. 3.4.4.4  Effect of pH  The pH of the leachate used in the experiments was ~7. To study the effect of pH on leaching rates, the pH was changed over the range of 5 to 8, which covers the pH for most MSW landfills. Typically, the leachate of younger landfills have lower pH and, with time, increases in pH tend to occur for landfill leachates (Slomczynska and Slomczynski 2004). Reagent grade glacial acetic acid was used to reduce the leachate pH to 5±0.05 and 6±0.05, whereas reagent grade sodium hydroxide was applied to increase the leachate pH to 8±0.05. To obtain a pH of 7±0.05, the leachate was used, with no acid or base added. Although no data were available about leaching rates of PFCs and the affecting factors, the effect of pH on other compounds e.g. metals were explored previously. In a study by Warner and Solomon (1990), the leaching rates of arsenic, chromium and copper were increased up to certain point by increasing pH, but decreased by further increasing the pH. 3.4.4.5 Individual carpets vs. composite Some experimental runs were designed to compare the leaching of PFCs from individual carpets with leaching from composite carpets. 100 g of each carpet sample (N4, N5, N6, N7, and N8) were contacted with 4 L of leachate in duplicate. These tests were carried out at room !  48  temperature with a rotational speed of 8 rpm. 3.4.4.6 Contacting with distilled water PFC leaching rates were explored in the absence of other agents e.g. organic and inorganic matter, metals, etc. This set of experiments was also intended to shed light on how the PFCs enter the aqueous media. HPLC grade water was used in these experiments to minimize crosscontamination. Similar to the experiments in section 3.4.3.4, the pH of distilled water was adjusted to 5±0.05, 6±0.05, 7±0.05, and 8±0.05 using glacial acetic acid or sodium hydroxide.  3.5 Quality Assurance/Quality Control (QA/QC) procedures 3.5.1 Leachate blank tests Leachate blank tests were conducted using 4 L of leachate with no pieces of carpet added. These tests were carried out to rule out possible changes in PFC concentration in leachate as a result of degradation of precursors during experiments and storage. A single leachate blank was associated with each set of experiments (except for the tests conducted with distilled water and for exploring the effect of pH). Table 3.3 represents the conditions of the leachate blank tests. 3.5.2 Operational blank test A single blank test was conducted with HPLC grade water. The objective was to determine the degree of probable cross-contamination from use of the sampling containers or tubes, sample handling, storage, and transportation. The blank test was carried out in the contacting device for 6 hours at 8 rpm and at room temperature. The pH, conductivity, and total dissolved solids were measured and recorded before and after each test.  !  49  Table 3.3: Leachate blank test conditions. Blank sample No.  Experiment type  Duration (h)  pH  Rotation speed (rpm)  Temperature (oC)  B.1  Effect of contact time  168  6  8  15 ± 3  B.2  Effect of rotation rate  6  6  8  15 ± 3  B.3  Effect of temperature  6  6  8  35 ± 1  6  6  8  15 ± 3  6  6  8  20 ± 1  B.4 B.5  Individual carpets vs. mixture Additional leachate blank test  3.5.3 Base case experiments A single base case experiment was carried out for each set of tests (except for one conducted with distilled water). Since the operational conditions in all of the base case experiments were similar, the results of these five tests provide an indication of the precision of the entire test series. QA/QC procedures for extraction and analysis are described in Sections 3.6 and 3.7.  3.6  Carpet and leachate sample extraction (DFO-IOS)  Extraction and clean-up of the samples are essential elements in concentrating and purifying the extract prior to analysis. The extraction and analysis of the samples in this study were performed at the Fisheries and Oceans Canada Institute of Ocean Sciences in Sidney, BC, by Dr. Jonathan Benskin under the guidance of Dr. Michael Ikonomou. Two different methods were used for extraction and analysis of carpet and leachate samples. This section describes each extraction method. 3.6.1 Extraction of carpet samples PFCs from carpet samples were extracted by the method described by L’Empereur et al.  !  50  (2008), with all carpet samples extracted in triplicate. Two, 2x2 cm carpet pieces were used for each extraction (approximately 5 g). Carpets were weighed and placed into a 50 ml polypropylene tube, then spiked with 22.5 ng of mass-labelled internal standards (13C4 PFBA, 13  C2 PFHxA,  13  C4 PFOA,  13  C5 PFNA,  13  C2 PFDA,  13  C4 PFOS). Internal standards were  applied to correct for the loss of analyte during sample preparation or sample inlet once required. The spiked carpets were allowed to sit for a few minutes until the solvent dried. Next, the extraction was carried out by adding 15 mL of methanol to the carpets for five times. After each stage of extraction with methanol, the centrifuge tubes were shaken in a vortex shaker for ~15 minutes. The extracts were reduced under nitrogen to a final volume of 45 mL and then spiked with 22.5 ng recovery standard (500 µg of a 500 ppb standard). The solution was then vortex-mixed and a portion of the extract was transferred to a 300 µL PP microvial for analysis by HPLC-MS/MS. In order to assess % recoveries, a spike-recovery experiment was performed in triplicate by spiking native PFC and precursor standards onto a blank carpet (containing no PFC), allowing it to dry, and then extracting with the above method. In addition, untreated carpet samples were extracted with the same method to determine any major problem with recovery of the analytes of interest. Extraction efficiency experiments were carried out for all carpet samples by performing a sixth methanol extraction, and analysing it separately. These experiments were conducted to confirm that all PFCs were extracted in the first five methanol extractions. Extraction efficiencies for each carpet were calculated through the following equation:  !  51  Extraction Efficiency (%) = [Analyte concentration obtained from the first five extractions/ Analyte concentration detected in the 6th methanol extract] x 100  3.6.2 Extraction of leachate samples The leachate extraction procedure was adopted from a previously developed USEPA method (US EPA 2011) for 45 mL leachate samples. Prior to extraction, the pH of samples was checked. Since all samples displayed a pH of 6 to 7, no pH adjustment was made. All samples and blanks were spiked with 2 ng of isotopically-labelled internal standards (13C4 PFBA, 13C2 PFHxA, 13C4 PFOA, 13C5 PFNA, 13C2 PFDA, 13C4 PFOS). SPE cartridges (Oasis® WAX 6cc, 500mg 30 µm) were conditioned with 5 mL of 0.3% NH4OH in methanol, 5 mL of 0.1M formic acid, and 5 mL of reagent HPLC-grade water prior to loading. Samples were vortexmixed, then loaded drop-wise (5 mL/min) under vacuum. After loading, the cartridges were washed with 5 mL of 20% methanol and 80% of 0.1 M formic acid in reagent water. The cartridges were dried under vacuum and eluted with 4 mL of 0.3% NH4OH in methanol afterwards. The extracted solution was spiked with recovery standard (2 ng 13C2FDUEA) and a portion was transferred into a conical vial for analysis by HPLC-MS/MS.  3.7 Instrumental analysis (DFO-IOS) The PFCs were analysed by liquid chromatography tandem mass spectrometry (LC/MS/MS) at the Fisheries and Oceans Canada Institute of Ocean Sciences (DFO-IOS) in Sidney, BC. A Dionex P680 HPLC using a Waters XTerra C18 (5 µm, 4.6 mm x 30 mm) reversed-phase column equipped with a Waters Opti-Guard C18 1 mm guard cartridge was utilized to separate the target analytes. In addition, the PFCs in the pump were separated from PFCs in  !  52  the samples by two Waters Xterra C18 (5 µm, 4.6 mm x 30 mm) columns, linked in series and placed upstream of the injector. In the initial conditions, the mobile phase consisted of 10% solvent A (100% MeOH) and 90% solvent B (0.1% ammonium hydroxide/ 0.1% ammonium acetate). The gradient elution program was: 0-1 min, 90% B, increase to 0% B by 8 min, maintain at 0% B until 12 min, return to stating conditions by 12.1 min, equilibrate for 4 min. Throughout the injection, the flow rate was held constant at 250 µL/min. Analysis of the samples was performed by an API 5000Q triple-quadrupole mass spectrometer (AB Sciex, Concord, ON, Canada) operating in negative ion Multiple Reaction Monitoring (MRM) mode. For each analyte, one or two precursor-production transitions were monitored. For the first 4.0 min of each run, the flow was diverted from the mass spectrometer by a Vici Valco diverter valve. The source temperature was 400°C. In order to target and quantify the analytes, Analyst v. 1.5.1 software was used. Weighted (1/x) linear regression calibrations were used to determine the concentration ranges. Analyte concentrations were then determined with respect to the mass-labelled internal standards, shown in Table 3.5. Each batch consisted of 12 samples. Four blanks (methanol) and one calibration standard (1 ppb) were processed between each batch. Method detection limits (MDLs) were assigned as 3 standard deviations above the mean blank levels. In cases when the blanks displayed non-detectable analyte concentration levels, the MDL was set equal to the instrument detection limit (IDL). The IDL was determined from the analyte peak response with a signal-to-noise ratio of 3:1. The MDL values in the analysis of leachate samples are summarized in Table 3.4. For purpose of statistical analysis, values of 0.5 MDL were assigned for the analytes for which the concentrations were below MDL. Since the extracted carpet weights were not equal for all samples, the measured MDL values  !  53  for carpet samples were sample-specific, i.e. each individual sample had a unique MDL. Thus the MDLs are not summarized in this section and were directly applied to the data reported in Section 4.1 where required. Table 3.4: Method Detection Limits (MDLs) for different PFCs in leachate sample analysis. PFC PFBA PFPA PFHxA PFHpA PFOA PFNA PFDA PFUnA  MDL (ng/mL) 0.019 0.077 0.125 0.080 0.887 0.381 0.013 0.009  PFC (continued) PFDoA PFTA PFBS PFHxS PFOS PFDS FOSA ---  MDL (ng/mL) 0.009 0.009 0.003 0.008 0.008 0.003 0.001 ---  Adopting internal standards in the analysis is essential to obtain data of as high a quality as possible in ultra-trace analysis. Under ideal conditions, each analyte should have an individual mass-labelled internal standard for maximum quantification accuracy. In this study, mass-labelled internal standards were available for 7 of the 18 PFCs of interest. Analytes with corresponding mass-labelled standards are highlighted by a (*) sign in Table 3.5. These analytes are expected to have the highest precision and accuracy in analyses. The mass-labelled internal standards could also be used for quantification of the remaining 11 analytes, for which the mass-labelled standards are lacking (e.g.  13  C2-PFHxA for  quantification of PFHpA). The mass-labelled internal standards are assigned to these analytes based on similarities in physical and chemical properties of the compounds, such as chemical structure and functional groups.  !  54  Table 3.5: Mass-labelled internal standards used in DFO-IOS lab. PFC *  Mass-labelled internal standard  PFBA  13  PFPeA  13  PFHxA  13  PFHpA  13  *  PFOA  13  *  PFNA  13  *  PFDA  13  PFUnA  13  PFDoA  13  PFTA  13  PFBS  13  PFHxS  13  *  PFOS  13  PFDS  13  FOSA  13  *  C4-PFBA  C4-PFBA  C2-PFHxA C2-PFHxA C2-PFOA C5-PFNA C2-PFDA C2-PFDA C2-PFDA C2-PFDA  C4-PFOS C4-PFOS C4-PFOS  C2-PFOA C4-PFOS  * Analytes for which mass-labelled internal standards are available in this study.  .  !  55  Chapter 4: Results and Discussion 4.1 Quality Assurance/Quality Control (QA/QC) 4.1.1 Leachate blank tests Concentrations of PFCs undergo changes over time due to biodegradation of precursors in raw leachate (See Section 3.5.1). Measured PFC levels in blank leachate samples (i.e. leachate samples having no contact with carpet) for different test conditions are summarized in Table 4.1. Samples are tagged with the same labels as in Table 3.3. Note that since a set of duplicate samples was available for blank leachate at a pH of 6, temperature of 15oC and contact time of 6 h, both mean and standard deviation values are provided. Figure 4.1 compares concentrations of PFCs of interest in blank leachate after 6 and 168 h at a pH of 6 and a temperature of 15oC. Except for PFBA, detected levels of PFCs were higher after 168 h than after 6 h, suggesting that biodegradation of precursors in blank leachate samples resulted in more PFC generation as time passed.  !  56  Table 4.1: Concentrations of different PFCs in leachate blank samples for various test conditions and pH of 6 in all cases. Underlined numbers show that corresponding PFC concentration was below MDL, and a value of 0.5 MDL was assigned. Test Type  Sample No.  PFBA  PFPA PFHxA PFHpA PFOA PFNA PFDA PFUnA PFDoA PFTA  PFBS PFHxS PFOS PFDS FOSA  B.2 (ng/mL)  0.054  0.329  0.201  0.097  0.044  0.191  0.019  0.004  0.007  0.010  0.001  0.046  0.053  0.002  0.000  0.120  0.538  0.345  0.114  0.044  0.191  0.010  0.004  0.005  0.012  0.001  0.063  0.073  0.002  0.000  0.087  0.434  0.273  0.106  0.044  0.191  0.015  0.004  0.006  0.011  0.001  0.055  0.063  0.002  0.000  0.047  0.148  0.102  0.012  0.000  0.000  0.006  0.000  0.001  0.002  0.000  0.012  0.014  0.000  0.000  0.065  0.605  0.357  0.134  0.044  0.191  0.026  0.011  0.019  0.021  0.011  0.064  0.068  0.002  0.003  0.124  0.115  0.159  0.117  0.044  0.191  0.033  0.019  0.016  0.018  0.001  0.052  0.059  0.002  0.000  0.071  0.338  0.373  0.093  0.044  0.191  0.011  0.003  0.007  0.014  0.006  0.060  0.062  0.002  0.000  0.009  0.038  0.324  0.079  0.044  0.191  0.013  0.004  0.005  0.004  0.001  0.057  0.081  0.002  0.000  B.4 • 6h (ng/mL) • 8 rpm Mean • 15oC (ng/mL) 1  S.Dev (ng/mL) • • • • • • • • •  168 h B.1 8 rpm (ng/mL) o 15 C 6h B.3 8 rpm (ng/mL) o 35 C 6h B.5 8 rpm (ng/mL) 20oC  • 0h 1  !  Mean (ng/mL)  Standard deviation, in ng/mL.  57  Analyte concentration (ng/mL)  0.7  6 h (Mean) 168 h  0.6 0.5 0.4 0.3 0.2 0.1 0.0  4-6 carbon PFCAs  7-9 carbon PFCAs  10-13 carbon PFCAs  PFSAs and FOSA  Figure 4.1: Concentrations of different PFCs in blank leachate after 6 and 168 h at pH of 6, temperature of 15oC and rotation speed of 8 rpm. 4.1.2 Operational blank test A single operational blank test with distilled water was conducted for 6 h at a pH of 6, temperature of 15oC and rotational speed of 8 rpm in order to ensure that no crosscontamination occurred. Concentrations of all analytes of interest in this sample were below the corresponding MDL, indicating that there was negligible cross-contamination during the experimental runs, sample handling, storage, extraction and analysis. 4.1.3 Base case experiments Table 4.2 summarizes the PFC concentrations leached from composite carpets to landfill leachate at base case conditions of pH 6, temperature 15oC, and rotation speed 8 rpm carried out in the pilot-scale “end-over-end contactor”. Data obtained from 0.5 MDL are excluded. Altogether, there were 5 samples at the base case conditions, providing a much greater sample !  58  Table 4.2: Different PFC concentrations obtained for tests conducted under base-case conditions (time=6 h, pH=6, temperature=15oC and rotation speed=8 rpm). Mean, standard deviation and standard error of mean are also included. No. Base Case. 1 (ng/mL) Base Case. 2 (ng/mL) Base Case. 3 (ng/mL) Base Case. 4 (ng/mL) Base Case. 5 (ng/mL) Mean (ng/mL)  PFBA  PFPA PFHxA PFHpA PFOA PFNA PFDA PFUnA PFDoA PFTA  0.133  0.685  2.005  1.632  0.563  0.829  0.405  0.085  0.328  0.610 0.5MDL 0.062  0.104 0.5MDL  0.132  0.740  1.360  1.321  0.407  0.679  0.324  0.122  0.219  0.412 0.5MDL 0.049  0.060 0.5MDL 0.5MDL  0.145  0.666  1.510  1.549  0.434  0.774  0.362  0.099  0.242  0.607 0.5MDL 0.066  0.077 0.5MDL  0.001  0.126  0.714  1.557  1.672  0.506  0.921  0.560  0.154  0.394  0.807 0.5MDL 0.070  0.102 0.5MDL  0.003  0.145  0.656  1.034  1.303  0.426  0.726  0.372  0.108  0.295  0.564  0.013  0.052  0.077 0.5MDL  0.001  0.136  0.692  1.493  1.495  0.467  0.786  0.405  0.114  0.296  0.600  0.003  0.060  0.084 0.5MDL  0.001  0.035  0.352  0.173  0.065  0.094  0.092  0.026  0.070  0.141  0.006  0.009  0.019  0.000  0.001  0.016  0.157  0.078  0.029  0.042  0.041  0.012  0.031  0.063  0.002  0.004  0.008  0.000  0.000  Standard 0.009 deviation(ng/mL) Standard error of 0.004 mean (ng/mL)  !  PFBS PFHxS PFOS  PFDS  FOSA 0.001  59  size obtained over several weeks of experimentation, than for the other data. No systematic variation with time is apparent in the data. The standard errors for PFC concentrations in Table 4.13 are small enough that the entire experimental series can be regarded as providing accurate and reproducible data.  4.2 PFC concentrations in carpet samples The concentrations of PFCs of interest in five different used and unused carpets are shown in Table 4.3. Note that since each carpet sample was extracted and analysed in triplicate, the mean value, standard deviation and standard error are displayed for each sample. The raw data and extraction efficiencies provided by the DFO-IOS lab are presented in Appendix C. Based on the data in Table 4.3, possible treatments for each carpet are proposed below: N4 : Very high concentrations of perfluorinated carboxylic acids (over 1000 ng/g of ΣPFCAs), which are residuals or degradation products of fluorotelomer alcohols (D’eon and Mabury 2011), indicate probable application of a Dupont Stainmaster product on this mill-treated carpet, which is primarily a mixture of both urethane and acrylic FTOH-based copolymers (Dupont Company 2001). Very low (~2 ng/g) concentrations of perfluorinated sulfonates, which are not typically present in Dupont Stainmaster products (Dupont Company 2001), support this assessment. PFHpA is the major contributor to PFC in this carpet (28% of total), followed by PFNA, PFPA and PFHxA, with these PFCAs accounting for more than 75% of the total PFC content of this carpet.  !  60  Table 4.3: Mean, standard deviation and standard errors of PFC concentrations (all in ng/g) in carpet samples analysed in this stud Underlined numbers show that corresponding PFC concentrations were below MDL, and a value of 0.5 MDL was assigned. No. Conc.  PFPA PFHxA PFHpA PFOA PFNA  PFDA PFUnA PFDoA PFTA  PFBS  PFHxS PFOS  PFDS  FOSA  9.0  171.8  160.6  302.0  57.9  185.7  91.8  22.5  30.2  21.80  0.1  0.1  2.0  0.1  0.0  1  S.Dev  2.9  1.8  6.0  20.7  1.9  3.2  1.8  1.2  0.5  1.5  0.0  0.0  0.4  0.0  0.0  2  S.E.M  1.7  1.0  3.5  12.0  1.1  1.8  1.1  0.7  0.3  0.9  0.0  0.0  0.2  0.0  0.0  Mean  3.8  55.7  94.7  150.8  38.0  104.3  54.7  19.9  10.3  11.6  0.1  4.74  4.5  0.1  0.1  S.Dev  1.5  2.7  5.3  8.3  2.2  4.6  3.8  1.5  0.5  2.0  0.0  0.83  0.8  0.0  0.0  S.E.M  0.9  1.6  3.1  4.8  1.2  2.6  2.2  0.8  0.3  1.1  0.0  0.5  0.4  0.0  0.0  Mean  8.5  102.3  170.6  122.7  103.5  125.9  273.6  81.4  180.4  291.6  3.0  0.4  76.6  1.0  13.8  S.Dev  1.5  17.9  38.8  24.9  16.3  16.4  36.3  8.7  64.5  86.4  4.8  0.3  16.2  0.9  0.2  S.E.M  0.9  10.3  22.4  14.4  9.4  9.5  21.0  5.0  37.2  49.9  2.8  0.2  9.4  0.5  0.1  Mean  2.4  7.7  32.3  46.7  9.7  28.9  12.4  3.3  1.8  2.90  0.2  0.4  26.5  0.2  0.1  S.Dev  0.0  8.5  3.4  39.1  2.9  5.2  2.8  1.4  0.7  0.4  0.0  0.2  3.7  0.0  0.00  S.E.M  0.0  4.9  2.0  22.6  1.7  3.0  1.6  0.8  0.4  0.2  0.0  0.1  2.1  0.0  0.00  Mean  2.4  7.7  1.1  1.2  0.2  0.5  0.23  0.2  0.1  0.2  0.1  0.1  2.1  0.1  0.0  S.Dev  0.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0  1.8  0.0  0.0  S.E.M  0.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0  1.0  0.0  0.0  Composite (Mean)  5.6  76.7  103.2  140.1  47.1  100.1  97.3  28.6  50.1  73.8  0.8  1.3  24.9  0.3  3.2  N7  N6  N5  N4  Mean  N8 3  PFBA  1  Standard Deviation Standard Error of Mean 3 PFC concentrations in composite carpet have been calculated based on the following formula (as discussed in Chapter 3): Mean Composite = 0.225 x (Mean N4 + Mean N5 + Mean N6 + Mean N7) + 0.1 x Mean N8 2  !  61  N5: Perfluorinated carboxylic acids in this mill-treated carpet are similar to PFCAs in carpet N4, but their concentrations are roughly half those in N4. Like N4, this carpet might have been treated with a Dupont Stainmaster product. PFHpA is the major component in this carpet (27% of total). N6 : This relatively old carpet contains significant amounts of both perfluorinated carboxylic acids and sulfonates. It has the highest PFC content among the carpets tested in this study: 44% more PFCs than N4, 3 times more than N5, 10 times more than N7 and 38 times more than N8. The presence of both PFCAs and PFSAs and their high concentrations in this carpet suggest that it was treated several times with different products. Higher concentrations of PFCAs compared to PFSAs and FOSA might be due to earlier treatments with Scotchgard, which contains NMeFOSE and perfluorosulfonate precursors (Dinglasan et al. 2006), followed by more recent treatments with Dupont Stainmaster products. N7 : This old and dusty carpet seems to have been treated several times with different products, but its low concentrations of PFCs suggest that several years have passed since the last treatment. PFHpA and PFHxA account for more than half of the PFC content of this carpet. N8 : Very low levels of PFCs (less than 20 ng/g of ΣPFCs) were detected in this carpet. Except for PFOS and PFPA, the PFC concentrations, displayed in Table 4.3, are simply the 0.5 Method Detection Limit (MDL) values of each of the corresponding analytes since no signal was detected when analysing the carpet samples for these PFCs.  !  62  Note that all extraction efficiencies of carpet samples in this study were more than 95%, suggesting that at least 95% of the PFCs were completely extracted from the carpet samples. For extraction efficiencies, see Table C.3 Appendix C.  4.3 Landfill leachate characterization Table 4.4 summarizes characterization results for pH, electrical conductivity, total dissolved solids (TDS), metals and total organic carbon (TOC) of leachate samples immediately after collection from the landfill and after 50 days of storage at 4oC. The physical and chemical characteristics of the leachate samples do not appear to have changed notably during storage at this temperature. PFC concentrations in leachate are presented in Table 4.5. Except for PFHxA, the background concentrations of PFCs in the urban landfill leachate sample are very low, in some cases below the method detection limits (MDL), where a value of 0.5MDL was assigned to the corresponding PFC. Figure 4.2 shows the percentage of each analyte in the leachate. Items along the x-axis are sorted in order of increasing number of carbon atoms in the PFCA and PFSA structure. Note that the major component of the leachate is PFHxA (38.0% of total PFCs), followed by PFNA (22.4%) and PFOS (9.5%). Among PFCAs present in the landfill leachates, perfluorinated carboxylic acids with 6 to 9 carbon atoms in their fluorinated chain are more dominant than PFCAs, with higher numbers of carbon atoms. This could be related to two factors: First, as discussed in Section 2.1, water solubilities of PFCAs decrease with increasing molecular weight, so that PFCAs with fewer carbon atoms have a higher tendency to solubilize in aqueous media. Second, perfluorinated compounds with 6 to 8 carbon atoms are preferred in manufacturing of polymeric materials and surfactants (D’eon and Mabury 2011), making their  !  63  corresponding PFCAs (as residuals in fluorinated polymers) dominant in commercial products and ultimately in landfill leachate. Table 4.4: Blank-corrected physical properties and chemical concentrations analysed for leachate immediately after collection and after 50 days of storage at 4oC. Test type  Analysed Parameters  pH Physical Conductivity (µs/cm) tests Total dissolved solids (TDS) (mg/L) As Be Cd Ca Cr Co Cu Fe Pb Mg Mn Metals Mo (mg/L) Ni Se Zn Sr Al Na K Ag Ba Sb Sn Organics Total organic carbon (mg/L) (TOC)  !  Leachate after collection 7.03 1392  Leachate after 50 days storage at 4oC 7.05 1402  674  678  0.000 0.000 0.011 91.880 0.007 0.006 0.028 9.673 0.008 21.740 0.600 0.011 0.000 0.035 0.039 0.496 1.049 95.340 18.200 0.000 0.182 0.025 0.051  0.000 0.000 0.005 85.088 0.001 0.004 0.031 9.096 0.011 22.100 0.432 0.009 0.017 0.047 0.075 0.519 0.645 99.206 36.647 0.000 0.195 0.036 0.039  66.0  71.4  64  Table 4.5: PFC concentrations in leachate. Mean values and standard deviations are calculated for each PFC. The Underlined numbers show that the corresponding PFC concentrations were below MDL and values of 0.5 MDL were assigned. Leachate Sample No.  Perfluorinated sulfonates (PFASs) and sulfonamide (FOSA) (ng/mL)  Perfluorinated carboxylic acids (PFCAs) (ng/mL) PFNA  PFDA  Leachate (1)  0.009  0.038  0.292  0.025  0.044  0.191  0.009  0.005  Leachate (2)  0.009  0.038  0.334  0.102  0.044  0.191  0.014  Leachate (3)  0.009  0.038  0.346  0.111  0.044  0.191  Mean (1,2,3) Standard deviation  0.009  0.038  0.324  0.079  0.044  0.000  0.000  0.028  0.047  0.000  Analyte Content Percentage (%)  PFBA PFPA PFHxA PFHpA PFOA  PFUnA PFDoA  PFTA  PFBS  PFHxS  PFOS  PFDS  FOSA  0.005  0.004  0.001  0.047  0.064  0.002  0.000  0.005  0.005  0.004  0.001  0.066  0.091  0.002  0.000  0.015  0.004  0.005  0.004  0.001  0.057  0.087  0.002  0.000  0.191  0.013  0.004  0.005  0.004  0.001  0.057  0.081  0.002  0.000  0.000  0.003  0.000  0.000  0.000  0.000  0.009  0.015  0.000  0.000  45 40 35 30 25 20 15 10 5 0  4-6 carbon PFCAs 7-9 carbon PFCAs  10-13 carbon PFCAs  PFSAs and FOSA  Figure 4.2: Percentages by mass of each PFC in total PFCs present in raw leachate. Compounds along the horizontal axis are in order of increasing number of carbon atoms for both PFCAs and PFSAs. !  65  4.4 Preliminary leaching experiments in bench-scale “end-over-end contactor” As noted in Chapter 3, the leaching experiments were carried out in two phases: preliminary tests and final tests. Since a few tests were carried out in the first phase (i.e. preliminary tests) and the outcomes were similar to those of final leaching tests, the preliminary test results are not discussed here. Appendix B summarizes the preliminary test results.  4.5 Final leaching experiments in pilot-scale “end-over-end contactor” The final leaching tests were intended to measure the leaching rates of different PFCs from carpet samples to real landfill leachate or distilled water for various contact times and operating conditions. Results are provided in this section. 4.5.1 Mass conservation equations in leaching experiments In order to verify the mass conservation of different PFCs in leaching experiments, mass balance equations are applied to a few cases. Generally, for a certain species in a system, a mass balance can be written as:  [Net input to the system] + [Generation due to chemical reaction] = [Net output] + [Consumption due to chemical reaction] + [Accumulation rate] To apply this approach to the leaching experiments, the following assumptions are made for the “system”, consisting of the carpet pieces and leachate in contact: •  [Net PFC input to the system] = [PFC input in carpet sample] + [PFC in leachate initially]  •  [Net PFC output from the system] = [PFC remaining on the carpet after contact] + [PFC in the leachate after contact with carpet]  !  66  •  Degradation and other reactions are ignored, given the limited duration of the experiments.  •  It is assumed that no accumulation occurred in the system.  Six carpet samples were analysed after contact with leachate/distilled water, and mass balances were applied to them. Table 4.6 shows the net inputs and outputs of different perfluorinated compounds in these tests, as well as PFC inputs and outputs from carpet samples and leachate/distilled water separately. Plotting the net output PFC amounts against net input PFC amounts resulted in regression lines with slopes between 0.68 and 0.88, and correlation coefficient (R2) values > 0.91 (indicating a good fit between the linear function and the experimental data), shown in Figure 4.3. Linear regression lines with slopes <1 in these charts suggest that, except in a few cases, the total amounts of PFCs decreased during the leaching experiments. Degradation of PFC precursors increases total PFCA and PFSA concentrations and would not explain a reduction in total PFC amounts. In addition, PFCAs and PFSAs do not appear to undergo degradation at low temperatures (5 to 35oC). A possible reason for the observed decline in PFC amounts is transferring of dusts containing PFCs from carpet samples to aqueous media, which might have settled at the bottom of tubes or have separated by filtration prior to extraction and analysis. In addition, some PFCs from carpets might have been adsorbed onto fine particles in the leachate, which settled in the tubes or were separated by filtration. A different trend was observed for PFBA net inputs and outputs. Unlike other PFCAs, in all mass balance equations in leachate samples (Mass balance No. 1, 2, 4, 5 and 6), the net output of PFBA was higher than the net input. Generation of PFBA as a result of biodegradation of PFC precursors, in particular 6:2 FTOH (Liu et al., 2010), during the experiments was  !  67  Table 4.6: Net inputs and outputs of different perfluorinated compounds from carpet and leachate samples in six leaching tests. Test condition Analysed parameters PFBA PFPA PFHxA PFHpA PFOA PFNA PFDA PFUnA PFDoA PFTA PFBS PFHxS PFOS PFDS FOSA  !  Mass Balance.1 Carpet input(ng) -Liquid: leachate Leachate input (ng) -Carpet: Carpet output (ng) Composite -Time: 168 h Leachate output (ng) -pH: 6 -Rotation: 8 rpm Net PFC input (ng) Net PFC output (ng) -Temp. : 15oC  464  7593 10309  36  152  1295  316  177  24  934  1122  2519  608  3741  8492  9500  500  14001 4705 10006 9731  2858  5010  7379  76  116  2281  20  310  17  20  16  4  226  323  8  1  1081 2889 3398  920  1278  1865  76  291  1102  31  221  2608 3825 1841  836  1916  3960  4  216  176  8  9  7745 11604  14318 4882 10770 9781  2876  5030  7375  80  343  2605  28  311  632  4675  9614  12019 3689 6714 5239  1756  3194  5825  80  508  1279  39  230  Mass Balance.2 Carpet input(ng) -Liquid: leachate Leachate input (ng) -Carpet: Carpet output (ng) Composite -Time: 6 h Leachate output (ng) -pH: 6 -Rotation: 0 rpm Net PFC input (ng) Net PFC output (ng) -Temp. : 15oC  464  7593 10309  14001 4705 10006 9731  2858  5010  7379  76  116  2281  20  310  36  152  1295  316  177  17  20  16  4  226  323  8  1  124  1933  3566  5230  2042 3969 5234  1777  2691  3597  76  56  1239  21  322  810  2311  4257  5456  1685 2693 2060  456  635  500  4  248  396  8  5  500  7745 11604  14318 4882 10770 9781  2876  5030  7395  80  343  2605  28  311  934  4244  7824  10687 3728 6662 7294  2234  3327  4097  80  304  1635  29  328  Mass Balance.3 Carpet input(ng) -Liquid: water Leachate input (ng) -Carpet: Carpet output (ng) Composite -Time: 6 h Leachate output (ng) -pH: 7 -Rotation: 8 rpm Net PFC input (ng) -Temp. : 15oC Net PFC output (ng)  464  7593 10309  14001 4705 10006 9731  2858  5010  7379  76  116  2281  20  310  36  152  248  160  177  16  20  28  4  16  16  8  1  62  1740  3148  4815  1656 3456 4417  1206  1969  2288  76  246  1055  20  275  353  3483  4818  7175  1754 4103 2453  508  831  2199  4  56  276  8  6  500  7745 10557  14161 4882 10770 9759  2874  5030  7407  80  132  2297  28  311  416  5223  7967  11991 3410 7559 6870  1715  2800  4488  80  302  1332  28  282  Mass Balance.4 Carpet input(ng) -Liquid: leachate Leachate input (ng) -Carpet: Carpet output (ng) Composite -Time: 6 h Leachate output (ng) -pH: 6 -Rotation: 8 rpm Net PFC input (ng) -Temp. : 20oC Net PFC output (ng)  464  7593 10309  14001 4705 10006 9731  2858  5010  7379  76  116  2281  20  311  36  152  1295  316  177  17  20  16  4  226  323  8  1  163  2238  3972  5812  2308 5647 5599  1637  2959  4407  76  81  1313  19  295  551  8930  6191  6191  1769 3180 1530  478  1377  3495  4  278  433  8  1  500  7745 11604  14318 4882 10770 9781  2876  5030  7395  80  343  2605  28  311  714 11168 10163  12003 4077 8827 7129  2115  4336  7902  80  359  1746  27  295  764  764  50  50  764 28.00  764  50  68  Table 4.6 (Continued): Net inputs and outputs of different perfluorinated compounds from carpet and leachate samples in six leaching tests. Test condition Analysed parameters PFBA PFPA PFHxA PFHpA PFOA PFNA PFDA PFUnA PFDoA PFTA PFBS PFHxS PFOS PFDS FOSA Mass Balance.5 Carpet input(ng) -Liquid: leachate Leachate input (ng) -Carpet: Carpet output (ng) Composite -Time: 6 h Leachate output (ng) -pH: 6 -Rotation: 8 rpm Net PFC input (ng) Net PFC output (ng) -Temp. : 5oC Mass Balance.6 Carpet input (ng) -Liquid: leachate Leachate input (ng) -Carpet: Carpet output (ng) Composite -Time: 24 h Leachate output (ng) -pH: 6 -Rotation: 8 rpm Net PFC input (ng) Net PFC output (ng) -Temp. : 35oC  !  464  7593 10309  2858  5010  7379  76  116  2281  20  310  36  152  1295  316  177  17  20  16  4  226  323  8  1  141  2304  4843  7423  2547 5164 5454  1462  2339  3559  76  98  1326  20  263  879  3669  5227  6319  1745 2604 1378  393  1494  3884  4  291  443  8  3  500  7745 11604  14318 4882 10770 9781  2876  5030  7395  80  343  2605  28  312  1020 5974 10071  13742 4292 7768 6832  1856  3834  7444  80  390  1769  28  266  464  7593 10309  14001 4705 10006 9731  2858  5010  7379  76  116  2281  20  310  36  152  1295  316  177  764  17  20  16  4  226  323  8  1  9  444  923  1946  782  2511 3091  772  1490  2025  76  115  1034  19  170  854  4200  9068  11464 3131 4910 2181  1009  1471  4123  4  182  187  8  12  500  7745 11604  14318 4882 10770 9781  2876  5030  7395  80  343  2605  28  312  863  4644  13410 3914 7421 5272  1782  2962  6149  80  298  1221  27  183  9992  14001 4705 10006 9731 764  50  50  69  Mass Balance No. 2  Mass Balance No. 1 14000 Net PFC output (ng)  14000 Net PFC output (ng)  12000 10000 8000 6000 4000 2000  12000 10000 8000 6000 4000 2000  0  y = 0.7456x - 193.85 R² = 0.94492  0  Net PFC input (ng)  y = 0.6764x + 27.344 R² = 0.97167  Mass Balance No. 4  Mass Balance No. 3 14000  12000 Net PFC output (ng)  Net PFC output (ng)  14000 10000 8000 6000 4000 2000  12000 10000 8000 6000 4000 2000  0  y = 0.7645x - 272.96 R² = 0.97549  0  Net PFC input (ng)  y = 0.8766x + 153.14 R² = 0.91126  14000 Net PFC output (ng)  Net PFC output (ng)  14000 12000 10000 8000 6000 4000  12000 10000 8000 6000 4000  2000  2000  0  0  Net PFC input (ng)  Net PFC input (ng)  Mass Balance No. 6  Mass Balance No. 5  y = 0.8548x - 105.24 R² = 0.96186  Net PFC input (ng)  y = 0.8201x - 458.2 R² = 0.93529  Net PFC input (ng)  Figure 4.3: Net output PFC amounts vs. net input PFC amounts (presented in Table 4.6). The “Mass Balance No.” on top of each chart corresponds to the numbers in Table 4.6. Each point displays the amount of a specific PFC in both the input and output of the system.  !  70  probably the major contributor to the observed elevated PFBA outputs. Note that this trend only occurred in leachate media; in distilled water, the PFBA output was lower than the input, because unlike landfill leachate, distilled water contained no PFC precursors. Generally, in all mass balances, the highest net PFC inputs and outputs were observed for PFHpA among the perfluorinated carboxylic acids (PFCAs), and for PFOS among the perfluorinated sulfonates (PFSAs).  !  71  4.5.2 Effect of contacting time on leaching rates As discussed in Section 3.4.4, experiments were performed where composite carpet samples were contacted with landfill leachate for contacting time intervals of 1 to 168 h in the pilotscale end-over-end contactor. Table 4.7 summarizes the results for leaching rates of different PFCs in five contacting time periods. Since all tests were in duplicate, the mean values and standard deviations are included in Table 4.7. Generally for PFCAs, a concentration increase was observed in leachate samples from 1 to 168 h, as shown in Figures 4.4(a) and 4.4(b). From Figure 4.4, except for PFPA and PFTA, all PFCA concentrations underwent a rapid initial increase followed by a slower increase during the 168 h contacting, i.e. leaching rates were higher for the first few hours compared to the last hours. Some PFCAs appear to have approached an equilibrium concentration after seven days of contact, while for others, considerable changes were witnessed in the PFC concentration gains between 24 h and 168 h. PFHxA, PFHpA, PFOA, PFNA, PFDA, and PFUnA were subject to minor (10% or less) concentration increases between 1 and 7 days, and it appears that these compounds either reached equilibrium (PFNA and PFDA), or nearly reach equilibrium shortly (PFHxA, PFHpA, PFOA, and PFUnA). The concentration of PFBA after the first day was ~14 times higher than at the beginning of the tests, while only an 18% increase in PFBA concentration was observed in the following 6 days. The observed trend for PFDoA was similar to that for PFBA. PFTA showed an unusual apparent decrease in concentration between 6 and 24 h, followed by a significant increase between 1 and 7 days.  !  72  Table 4.7: Mean PFC concentrations and their standard deviations in leachate samples after contacting with composite carpet samples at pH=6, temperature=15oC, rotation speed=8 rpm and certain contacting times. Underlined numbers show that corresponding PFC concentration was below MDL, and a value of 0.5 MDL was assigned. Time (h) 1  2  6  24  168 1  Parameter PFBA PFPA PFHxA PFHpA PFOA PFNA PFDA PFUnA PFDoA PFTA Mean (ng/ml)  PFBS PFHxS PFOS PFDS FOSA  0.009 0.475  0.846  0.773  0.044  0.455  0.321  0.078  0.161  0.182  0.009  0.051  0.070  0.002 0.000  S.Dev  0.000 0.124  0.029  0.030  0.011  0.036  0.004  0.003  0.012  0.006  0.003  0.004  0.006  0.000 0.000  Mean (ng/mL)  0.068 0.754  1.191  1.379  0.425  0.729  0.360  0.111  0.213  0.330  0.001  0.075  0.092  0.002 0.001  S.Dev  0.011 0.291  0.141  0.100  0.029  0.050  0.009  0.026  0.049  0.066  0.000  0.004  0.007  0.000 0.000  Mean (ng/mL)  0.133 0.713  1.682  1.476  0.485  0.754  0.364  0.104  0.274  0.511  0.001  0.056  0.082  0.002 0.001  S.Dev  0.001 0.039  0.456  0.220  0.111  0.106  0.057  0.026  0.077  0.141  0.000  0.009  0.031  0.000 0.000  Mean (ng/mL)  0.136 1.267  1.988  2.016  0.588  0.924  0.424  0.180  0.288  0.450  0.005  0.057  0.061  0.002 0.003  S.Dev  0.016 0.028  0.133  0.087  0.043  0.009  0.042  0.007  0.012  0.041  0.006  0.003  0.008  0.000 0.000  Mean (ng/mL)  0.161 0.871  2.152  2.234  0.633  0.921  0.431  0.191  0.410  0.848  0.001  0.051  0.042  0.002 0.002  S.Dev  0.012 0.091  0.041  0.199  0.027  0.050  0.041  0.026  0.098  0.202  0.000  0.005  0.003  0.000 0.000  1  1  1  1  Standard deviation, also in ng/mL.  Table 4.8: Concentrations of remaining PFCs in composite carpet samples after 6 and 168 h contact with landfill leachate at pH=6, temperature=15oC and rotation speed=8 rpm.  !  Time (h)  PFBA (ng/g)  PFPA (ng/g)  PFHxA (ng/g)  PFHpA (ng/g)  PFOA (ng/g)  PFNA (ng/g)  PFDA (ng/g)  PFUnA PFDoA (ng/g) (ng/g)  PFTA (ng/g)  PFBS (ng/g)  PFHxS (ng/g)  PFOS (ng/g)  PFDS (ng/g)  FOSA (ng/g)  6  1.63  22.38  39.72  58.12  23.08  56.47  55.99  16.37  29.59  44.07  0.11  0.87  10.24  0.11  2.95  168  0.79  3.34  11.23  25.20  10.81  28.89  33.98  9.20  12.79  18.65  0.09  2.92  12.26  0.09  2.22  73  Analyte Concentration (ng/mL)  (a) 2.5 2  PFBA 1.5  PFPA PFHxA  1  PFHpA PFOA  0.5 0 0  20  40  60  80  100  120  140  160  180  Contact Time (h)  Analyte Concentration (ng/mL)  (b) 1 0.8  PFNA PFDA  0.6  PFUnA 0.4  PFDoA PFTA  0.2 0 0  20  40  60  80  100  120  140  160  180  Contact Time (h)  (c) Analyte concentration (ng/ mL)  0.1 0.08 0.06  PFHxS PFOS  0.04 0.02 0 0  20  40  60  80  100  120  140  160  180  Contact time (h)  Figure 4.4: Concentrations of (a) PFBA, PFPA, PFHxA, PFHpA, PFOA (b) PFNA, PFDA, PFUnA, PFDoA, PFTA, (c) PFHxS, and PFOS in leachate samples after contacting with composite carpet samples at pH=6, temperature=15oC, rotation speed=8 rpm versus contact time. PFBS, PFDS, and FOSA are not included because their concentrations were below or slightly above MDLs. !  74  A different trend was witnessed for all perfluorinated sulfonates and FOSA, as well as PFPA; the concentration decreased between 2 and 168 h for PFHxS and PFOS, and between 6 and 24 h for PFPA. For PFHxS and PFOS, this concentration decrease appears to have been due to reverse mass transfer of analytes i.e. from leachate to carpet. Table 4.8 displays changes in concentrations of PFCs in carpet samples between 6 and 168 h at 15oC. The table indicates that concentrations of all PFCAs in carpet decreased significantly from 6 to 168 h as a result of mass transfer to the leachate, while PFHxS and PFOS in carpet samples experienced an increase in concentration during this period, consistent with possible migration of PFHxS and PFOS from carpets to leachate. Figure 4.5 shows the overall changes of total PFC concentrations in the 1-168 h period. The total amounts of PFCs are equal to the summations of leached PFC concentrations shown in Figure 4.4 (a), (b) and (c), which are mostly controlled by the PFCs shown in Figure 4.4 (a) and (b), since PFCAs were the dominant PFCs in the leachate. The best fitted line in this plot  Σ PFC concentration (ng/mL)  (i.e. y = 0.95 ln(x) + 4.67) is very close to a logarithmic equation line. 12 10 8 6 4 2 0  y = 0.9496 ln(x) + 4.6677 R² = 0.89889  Time (h)  Figure 4.5: Total PFC concentrations in leachate samples after contacting with composite carpet samples at pH=6, temperature=15oC and rotation speed=8 rpm, versus contact time.  !  75  4.5.3 Effect of rotation speed on leaching rates Table 4.9 summarizes leaching rates of different PFCs to landfill leachate for identical pH, temperature, and contact times, with rotational speed of the pilot-scale “end-over-end contactor” varying between 0 – 8 revolutions per minute (rpm). With the experiments were carried out in duplicate, the mean and standard deviations are displayed in Table 4.9. It appears that except for PFTA, varying the rotation speed, i.e. the extent of mixing the contents of vessels, did not affect the leaching rates significantly. The slopes of linear regression lines which best fit the leaching rates at “8 rpm versus 0 rpm”, and “4 rpm versus 0 rpm”, shown in Figure 4.6 (a) and 4.6 (b) respectively, are close to 1, implying that the leaching rates were not significantly dependent on rotation. There are two principal mechanisms of mass transfer between subsystems: diffusion and convection. For no rotation, only diffusion occurs, whereas convective transport augments external mass transport when there is rotation. For all species tested except PFTA, rotation appears to have had little or no effect on the leaching rate, showing that the leaching rates were dependent on some factor (e.g. adsorption or desorption) other than external mass transfer. For PFTA, as labelled in Figure 4.6, a significant increase was observed due to rotation, whether at 4 rpm or 8 rpm. The leached PFTA concentrations in the leachate with rotation were almost 5 times higher than without rotation, suggesting that external mass transfer played a dominant role in determining the overall mass exchange of PFTA between carpets and leachate. Note that PFTA leaching rates were almost equal at 4 rpm and 8 rpm, suggesting that external mass transfer was favorable enough at either rotation speed, for the overall rate to be no longer external mass transfer controlled. !  76  Table 4.9: Mean PFC concentrations and their standard deviations in leachate samples after contacting with composite carpet samples for 6 h at pH=6, temperature=15oC and varying rotation speeds (0, 4 and 8 rpm). Underlined numbers show that corresponding PFC concentration was below MDL, and a value of 0.5 MDL was assigned. Rate Parameter PFBA 0 rpm  4 rpm  8 rpm 1  !  PFPA PFHxA PFHpA PFOA PFNA PFDA PFUnA PFDoA PFTA  PFBS PFHxS PFOS PFDS FOSA  0.194  0.594  1.229  1.376  0.445  0.650  0.494  0.113  0.150  0.116  0.012  0.064  0.105  0.002 0.001  S.Dev  0.013  0.022  0.233  0.016  0.034  0.033  0.030  0.002  0.012  0.013  0.016  0.002  0.008  0.000 0.000  Mean (ng/mL)  0.271  0.723  1.690  1.822  0.535  0.855  0.439  0.161  0.289  0.637  0.001  0.067  0.110  0.002 0.002  S.Dev  0.014  0.053  0.049  0.164  0.055  0.037  0.028  0.021  0.069  0.097  0.000  0.000  0.000  0.000 0.000  Mean (ng/mL)  0.145  0.661  1.386  1.551  0.430  0.750  0.367  0.104  0.269  0.585  0.007  0.059  0.077  0.002 0.001  0.000  0.007  0.176  0.002  0.006  0.034  0.007  0.007  0.038  0.030  0.009  0.010  0.000  0.000 0.000  Mean (ng/ml) 1  1  1  S.Dev  Standard deviation, also in ng/mL.  77  (b) 2.0 PFC Concentration at 4 rpm (ng/mL)  PFC Concentration at 8 rpm (ng/mL)  (a) 1.8 1.6 1.4 1.2 1.0 0.8  PFTA  0.6 0.4 0.2 0.0  0.0  0.2  0.4  0.6  0.8  1.0  1.2  1.4  1.6  y = 1.0797x + 0.0271 PFC Concentration at 0 rpm (ng/mL) R² = 0.92324  1.8 1.6 1.4 1.2 1.0 0.8  PFTA  0.6 0.4 0.2 0.0 0.0  0.2  0.4  0.6  0.8  1.0  1.2  1.4  1.6  y = 1.2783x + 0.0345 PFC Concentration at 0 rpm (ng/mL) R² = 0.93758  PFC Concentration at 8 rpm (ng/mL)  (c) 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6  PFTA  0.4 0.2 0.0 0.0  0.2  0.4  y = 1.172x + 0.0075 R² = 0.99504  0.6  0.8  1.0  1.2  1.4  1.6  PFC Concentration at 4 rpm (ng/mL)  Figure 4.6: PFC concentrations in leachate samples after contacting with composite carpet samples for 6 h at pH=6, temperature=15oC and rotation speed of (a) 8 vs. 0 rpm, (b) 4 vs. 8 rpm and (c) 8 vs. 4 rpm. 4.5.4 Effect of temperature on leaching rates PFC leaching rates at two temperatures, 5±1oC and 35±1oC, were obtained for contact times of 2, 6 and 24 h between composite carpet and leachate samples. The results are shown in Table 4.10. PFC leaching rates at 15oC are also included in Table 4.10.  !  78  Table 4.10: Concentrations of PFCs leached from composite carpet samples to leachate at 5±1, 15±3 and 35±1oC, pH 6 and rotation speed 8 rpm for 2, 6 and 24 h contact time. PFC concentrations of blank leachate are also included in the last line. Underlined numbers show that corresponding PFC concentration was below MDL, and a value of 0.5 MDL was assigned. Temp. (oC)  (5±1)oC  (15±3)oC  (35±1) oC  Raw Leachate  Time PFBA PFPA PFHxA PFHpA PFOA PFNA PFDA PFUnA PFDoA PFTA PFBS PFHxS PFOS PFDS FOSA (h) (ng/ml) (ng/ml) (ng/ml) (ng/ml) (ng/ml) (ng/ml) (ng/ml) (ng/ml) (ng/ml) (ng/ml) (ng/ml) (ng/ml) (ng/ml) (ng/ml) (ng/ml) 2  0.126  0.570  0.923  1.011  0.349  0.561  0.372  0.163  0.299  0.548  0.001  0.075  0.091  0.002  0.001  6  0.127  0.793  1.073  1.372  0.393  0.573  0.322  0.090  0.323  0.798  0.001  0.068  0.093  0.002  0.000  24  0.128  0.790  1.197  1.587  0.457  0.755  0.289  0.106  0.341  0.858  0.007  0.067  0.066  0.005  0.000  2  0.068  0.754  1.191  1.380  0.425  0.729  0.361  0.112  0.213  0.330  0.001  0.075  0.092  0.002  0.001  6  0.133  0.713  1.682  1.476  0.485  0.754  0.364  0.104  0.274  0.511  0.001  0.056  0.082  0.002  0.001  24  0.136  1.109  1.988  2.016  0.588  0.924  0.424  0.180  0.288  0.450  0.005  0.057  0.061  0.002  0.004  2  0.135  2.088  1.546  1.892  0.562  0.956  0.560  0.168  0.345  0.708  0.001  0.073  0.097  0.002  0.000  6  0.123  1.199  1.600  1.899  0.511  0.923  0.457  0.128  0.241  0.556  0.006  0.050  0.075  0.002  0.001  24  0.244  1.020  2.330  2.910  0.742  1.143  0.529  0.222  0.334  0.910  0.001  0.048  0.050  0.002  0.002  0  0.009  0.038  0.324  0.079  0.044  0.191  0.013  0.004  0.005  0.004  0.001  0.057  0.081  0.002  0.000  ! ! ! ! ! ! ! !  !  79  As noted in Section 4.5.3, except for PFTA, leaching rates of PFCs are not mass transfer controlled, but are likely adsorption/desorption controlled, in which case it is expected that the PFC adsorption/desorption rate constants are proportional to e-Ea/RT according to the “Arrhenius law”: -Ea/RT  k = ko e  (4.1)  The Arrhenius equation, in brief, gives the dependence of k (rate constant) on T (absolute temperature, i.e. in Kelvin) and EA (activation energy), where R is the gas constant. In addition, assuming a first order reaction for species A, one can expect: (rA) = k (CA, equilibrium – CA) where for species A, (rA) is the leaching rate, k is a rate constant, CA,  (4.2) equilibrium  is the  equilibrium concentration and CA is the concentration in the leachate. Substituting for k from Equation (4.1) in Equation (4.2) and taking natural logarithm of both sides results in: ln [rA/ ko (CA, equilibrium – CA)] = - (EA / RT)  (4.3)  Therefore, the results for ln (CA/CA, equilibrium) could be plotted against (1/T) in an Arrhenius plot, with the slope being equal to - (EA / R). However, the equilibrium concentration of species A (i.e. CA, equilibrium) is very likely temperature dependent, but the data for this are not available in this study. Experiments should be conducted in the future to determine the equilibrium concentrations of PFCs in different temperatures. In plots similar to Arrhenius plot, the PFCA concentrations in landfill leachate after contact with composite carpet samples for 2, 6 and 24 h are plotted versus (1/T), where T is the absolute temperature (i.e. in Kelvin), as shown in Figure 4.7. Note that for each contact time, PFCAs of 4-8 carbon atoms and 9-13 carbon atoms are plotted separately. !  80  PFHxA 2  PFHpA PFOA  1.5 1 0.5  0.0033  0.0034  0.0035  PFNA PFDA  PFPA  2.5  0 0.0032  (b) 2 h contact time, PFCAs of 9-13 carbon atoms  PFBA Analyte concentration (ng/mL)  Analyte concentration (ng/mL)  (a) 2h contact time, PFCAs of 4-8 carbon atoms  1.2  PFUnA  1  PFDoA PFTA  0.8 PFTA  0.6 0.4 0.2 0 0.0032  0.0036  0.0033  0.0034  0.0035  0.0036  1/T (K-1)  1/T (K-1)  !  ! PFPA 2  PFHxA PFHpA  1.5  PFOA 1  0.5  0 0.0032  0.0033  0.0034 1/T (K-1)  0.0035  0.0036  (d) 6 h contact time, PFCAs of 9-13 carbon atoms  PFBA Analyte concentration (ng/mL)  Analyte concentration (ng/mL)  (c) 6 h contact time, PFCAs of 4-8 carbon atoms  PFNA PFDA  1  PFUnA 0.8  PFDoA  PFTA  PFTA  0.6 0.4 0.2 0 0.0032  0.0033  0.0034  0.0035  0.0036  1/T (K-1)  ! Figure 4.7: Concentrations of PFCAs in landfill leachate after contact with composite carpet for (a), (b) 2 h and (c), (d) 6 h vs. (1/T), where T is absolute temperature. Leaching experiments were conducted at pH 6, rotation speed 8 rpm and temperature 5, 15 and 35oC (Figure continued on next page).  !  !  81  (e) 24 h contact time, PFCAs of 4-8 carbon atoms  Analyte concentration (ng/mL)  PFHxA 2.5  PFHpA PFOA  2 1.5 1 0.5  0.0033  0.0034 1/T (K-1)  0.0035  0.0036  Analyte concentration (ng/mL)  PFPA  3  0 0.0032  (f) 24 h contact time, PFCAs of 9-13 carbon atoms  PFBA 1.2 1 0.8  PFNA PFDA PFUnA PFDoA PFTA  PFTA  0.6 0.4 0.2 0 0.0032  0.0033  0.0034  0.0035  0.0036  1/T (K-1)  Figure 4.7 (continued): Concentrations of PFCAs in landfill leachate after 24 h contact with composite carpet vs. (1/T), where T is absolute temperature. Leaching experiments were conducted at pH 6, rotation speed 8 rpm and temperature 5, 15 and 35oC.  !  82  From Figure 4.7, it appears that the leaching rates of PFPA, PFHxA, PFHpA, PFNA and PFDA underwent a decrease with increasing (1/T); in other words, the leaching rates of these PFCAs increased with temperature, as expected for adsorption- /desorption-controlled transfer. On the other hand, PFBA, PFOA, PFUnA and PFDoA experienced little concentration changes with temperature, suggesting that temperature did not significantly affect the transfer rates of these compounds. For PFTA, however, a totally different trend was observed, as seen in Figure 4.7. Since PFTA was the only analyte for which the transport was externally mass transfer controlled, the effect of temperature on leaching rates of PFTA is discussed separately in this section. Figure 4.8 shows the concentrations of PFTA in landfill leachate after 2, 6 and 24 h contact with composite carpet at pH 6, rotation speed 8 rpm and temperature 5, 15 and 35oC. From Figure 4.8, it appears that PFTA increased from 0 to 2 h at all temperatures (i.e. 5, 15 and 35oC), with the highest concentration observed at 35oC. At 5oC a slight increase in PFTA concentration was observed from 2 to 24 h. At 15oC after a minor decrease in PFTA levels between 2 and 6 h, a slight increase was observed from 6 to 24 h. However at 35oC not only the observed decrease in PFTA level after 2 h was more significant than the decrease observed at 15oC, but also this drop in concentration occurred earlier compared to 15oC (at which the smaller decrease occurred after 6 h), implying higher transfer rates at 35 oC. Note that this trend could not be confirmed unless more data at various times from 0 to 168 h were available.  !  83  Analyte concentration (ng/mL)  PFTA  5C  1.2  15 C  1 35 C  0.8 0.6 0.4 0.2 0 0  5  10  15  20  25  30  Time (h)  Figure 4.8: Leaching rates of PFTA from composite carpet samples to leachate at 5, 15 and 35oC after 2, 6 and 24 h contact time. These leaching experiments were conducted at pH 6 and rotation speed 8 rpm. Trends for variation of PFSA leaching rates differed from those observed in PFCAs. Since concentrations of PFBS, PFDS, and FOSA were close to or below the MDLs, only leaching rates of PFHxS and PFOS are discussed in this section. Concentrations of PFHxS in leachate were similar after 2 h of contact with carpet samples at 5, 15 and 35oC, but decreased abruptly from 2 to 6 h, as shown in Figure 4.9 (a). The greatest rate of PFHxS concentration decrease from 2 to 6 h was observed at 35oC, followed by 15 and 5oC respectively. From 6 to 24 h, the concentration of PFHxS at all temperatures remained almost constant. The higher rate of PFHxS loss in leachate at the higher temperatures suggests that temperature speeds up the partitioning of PFHxS from leachate to carpet (i.e. reverse direction transfer). For PFOS, shown in Figure 4.9 (b), a steep concentration decrease was observed from 2 to 24 h, with the greatest rate of analyte decline at 35oC, followed by 15 and 5oC respectively. Similar to PFHxS in the range of 5 to 35oC, higher temperatures accelerated PFOS transfer.  !  84  (b)  15 C 35 C  0.07  0.06  0.05  0.04 0  5  10  15  PFOS  5C  PFHxS  0.08  20  25  Time (h)  30  Analyte concentration (ng/mL)  Analyte concentration (ng/mL)  (a)  5C  0.1  15 C  0.09  35 C  0.08 0.07 0.06 0.05 0.04 0  5  10  15  20  25  30  Time (h)  Figure 4.9: Leaching rates of (a) PFHxS and (b) PFOS from composite carpet to landfill leachate at 5, 15 and 35oC for 2, 6 and 24 h contact time. The leaching experiments were conducted at pH 6 and rotation speed 8 rpm. 4.5.5 Effect of pH on leaching rates A series of tests was carried out to determine the effect of pH on leaching rates of different PFCs. Table 4.11 summarizes the concentrations of PFCs in leachate samples after contact with composite carpet samples for 6 h at a rotational speed of 8 rpm in the pilot-scale “endover-end contactor” at varying pH values of 5, 6, 7 and 8. With the experiments were conducted in duplicate, the mean and standard deviation values are included in the Table 4.11. Generally, increasing the leachate pH from 5 to 6 and 6 to 7 resulted in an increase in total concentrations of PFCs, as well as total PFCAs, as shown in Figure 4.10. However, further increasing the pH from 7 to 8 caused a decline in the total concentrations of PFCs and PFCAs. This trend is very similar to that observed by Warner and Solomon (1990) for leaching rates of metals into solutions of varying pH (see Section 3.4.4.4).  !  85  Table 4.11: Mean and standard deviation of PFC concentrations (in ng/mL) in leachate after contacting with composite carpet samples at pH=6, temperature=15oC, rotation speed=8 rpm and solution pH of 5, 6, 7, and 8. Underlined numbers show that the corresponding PFC concentrations were below MDL, and values of 0.5 MDL were assigned in these cases. pH Parameter PFBA 5  6  7  1  1  1  8 1  1  !  PFPA PFHxA PFHpA PFOA  PFNA  PFDA PFUnA PFDoA PFTA  PFBS  PFHxS PFOS PFDS FOSA  Mean  0.143  0.725  1.331  1.544  0.461  0.717  0.396  0.136  0.369  0.712  0.001  0.066  0.078  0.002 0.002  S.Dev  0.015  0.037  0.017  0.055  0.035  0.095  0.013  0.024  0.048  0.077  0.000  0.001  0.004  0.000 0.000  Mean  0.130  0.700  1.781  1.652  0.535  0.875  0.483  0.128  0.361  0.709  0.001  0.066  0.103  0.002 0.002  S.Dev  0.005  0.021  0.317  0.028  0.040  0.065  0.110  0.037  0.047  0.139  0.000  0.006  0.001  0.000 0.001  Mean  0.222  0.628  1.656  1.893  0.540  0.937  0.514  0.181  0.313  0.727  0.005  0.080  0.092  0.002 0.002  S.Dev  0.012  0.031  0.094  0.160  0.040  0.086  0.074  0.030  0.044  0.018  0.005  0.001  0.004  0.000 0.000  Mean  0.171  0.543  1.290  1.458  0.431  0.840  0.474  0.173  0.244  0.487  0.008  0.063  0.087  0.002 0.004  S.Dev  0.016  0.027  0.099  0.105  0.011  0.032  0.015  0.013  0.008  0.025  0.010  0.006  0.000  0.000 0.001  Standard deviation, also in ng/mL.  86  Σ PFCs  Concentration (ng/mL)  8  Σ PFCAs 7.5  7  6.5  6 5  6  7  8  pH  Figure 4.10: Total concentrations of PFCAs and PFCs in leachate after contacting with composite carpet samples at pH=6, temperature=15oC, rotation speed=8 rpm and solution pH of 5, 6, 7, and 8. As shown in Figure 4.10, total concentrations of leached PFCAs were very close to total concentrations of PFCs. Perfluorinated sulfonates (PFSAs) comprised ~2.5% of total PFC concentrations in leachate in this study. Concentrations of different PFCs in leachate after 6 h of contact between composite carpet samples and leachate at 15oC and varying pH are displayed in Figure 4.11. Compounds along the x-axis have been arranged in order of increasing number of carbon atoms in the fluorinated chain. Except for a few PFCs, the highest leaching rates were observed for a pH of 7, and in a few cases, at pH 6. Concentrations of PFHpA, PFNA, PFDA, PFUnA, PFTA, and PFHxS reached their highest levels at pH of 7, while the greatest concentrations of PFBA, PFHxA, and PFOS were detected at a pH of 6. PFPA and PFDoA followed a different trend, as more acidic solutions resulted in greater leaching rates for these two PFCAs. The leaching behaviour of PFBS, PFDS, and FOSA are not discussed here because of their concentrations being below or slightly above MDL levels so that these data are not sufficiently accurate to draw valid conclusions. !  87  Analyte concentration (ng/mL)  2.0  pH = 5  1.8  pH = 6 pH = 7  1.6  pH = 8  1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0  4-6 carbon PFCAs  7-9 carbon PFCAs  10-13 carbon PFCAs  PFSAs and FOSA  Figure 4.11: Concentrations of different PFCs leached from composite carpet samples to leachate after 6 h contact time at temperature=15oC, rotation speed=8 rpm and pH of 5, 6, 7, and 8. 4.5.6  Leaching rates of PFCs from samples of individual carpet compared to the  composite samples Some experimental runs were designed to compare leaching from composite and individual carpets (N4, N5, N6, N7 and N8) with landfill leachate, to determine the leaching rates of different PFCs (See Section 3.4.4.5). Because observed PFC concentrations in the leachate included both PFCs leached from carpet samples and PFCs present in the background leachate, the results were corrected with leachate blanks and are summarized in Table 4.12.  !  88  The procedure for blank-correction was as follows: [PFC concentration leached from carpet to leachate] = [Final PFC concentration in the leachate after contact with carpet] – [Concentration of PFCs in the leachate without any carpet present after the same time (6 h) at the same temperature] Through this method, comparison between PFC leaching rates from individual and composite carpets was made feasible. For leachate blank samples, see Section 4.1.1. Since composite carpet samples were composed of N4, N5, N6, N7 (22.5 wt. % each), and N8 (10 wt. %), it is expected that if there are no synergistic effects, the PFC leaching rates from composite carpet samples would match that from a weighted average, i.e. from: [PFC concentration leached from composite carpet] = 0.225 × [Summation of PFC concentrations leached from carpets N4, N5, N6 and N7] + 0.1 × [PFC concentrations leached from carpet N8]  The “Expected PFCA leaching rates from composite carpets” based on this equation are plotted against the “Experimental PFCA leaching rates from composite carpets” in Figure 4.12. The results for perfluorinated sulfonates are not included because most concentrations were below the MDL. There are significant differences between the measured and expected data. Except for PFPA, highlighted in Figure 4.12, the discrepancy appears to be greater with increasing concentration. The expected concentration for PFPA was ~4 times greater than the experimental concentration.  !  89  Table 4.12: PFC concentrations in leachate after contact with composite and individual carpets (N4, N5, N6, N7 and N8) at 15oC, pH 6 and rotation speed 8 rpm. Tabulated concentrations are final concentrations in leachate after correcting for concentration of PFCs in leachate with no carpet and identical time, temperature and rotation speed. Carpet Parameter PFBA No. Mean 0.261 (ng/ml) N4 1 S.Dev 0.051 N5  N6  N7  N8  Mixed 1  !  PFPA PFHxA PFHpA PFOA PFNA PFDA PFUnA PFDoA PFTA  PFBS PFHxS PFOS PFDS FOSA  1.162  3.332  5.620  1.008  2.303  0.482  0.047  0.094  0.161  0.000  0.029  0.018  0.000 0.000  0.034  0.375  0.079  0.042  0.133  0.039  0.000  0.008  0.006  0.000  0.003  0.007  0.000 0.000  0.381  1.003  1.213  0.768  0.286  0.299  0.190  0.057  0.168  0.052  0.000  0.002  0.000  0.000 0.000  S.Dev  0.080  0.267  0.559  0.148  0.036  0.121  0.039  0.018  0.162  0.012  0.000  0.012  0.011  0.000 0.000  Mean (ng/mL)  0.210  0.499  1.196  0.601  0.575  0.414  0.942  0.313  1.312  2.612  0.013  0.012  0.088  0.000 0.010  S.Dev  0.071  0.132  0.172  0.052  0.026  0.016  0.002  0.016  0.062  0.308  0.021  0.005  0.002  0.000 0.001  Mean (ng/mL)  0.235  0.679  0.390  0.672  0.186  0.100  0.101  0.039  0.034  0.071  0.003  0.026  0.017  0.000 0.000  S.Dev  0.041  0.200  0.077  0.230  0.044  0.052  0.017  0.000  0.000  0.004  0.006  0.006  0.007  0.000 0.000  Mean (ng/mL)  0.034  0.259  0.000  0.087  0.035  0.000  0.000  0.000  0.041  0.134  0.032  0.051  0.297  0.000 0.000  S.Dev  0.050  0.067  0.061  0.062  0.022  0.000  0.007  0.000  0.022  0.083  0.049  0.012  0.060  0.000 0.000  Mean (ng/mL)  0.061  0.216  0.908  1.436  0.390  0.559  0.342  0.092  0.253  0.537  0.005  0.006  0.012  0.000 0.001  0.004  0.054  0.254  0.332  0.012  0.034  0.023  0.017  0.051  0.021  0.009  0.015  0.003  0.000 0.000  Mean (ng/mL) 1  1  1  1  1  S.Dev  Standard deviation, also in ng/mL.  90  Experimental PFCA leached from composite carpet to leachate (ng/mL)  1.6 PFHpA  1.4 1.2 1.0  PFHxA  0.8 PFTA  0.6  PFNA PFDA PFOA  0.4 0.2  PFPA  PFDoA  PFUnA PFBA  0.0 0.0  0.2  0.4  0.6  0.8  1.0  1.2  1.4  1.6  1.8  2.0  Expected PFCA leached from composite carpet based on weighted average(ng/mL)  Figure 4.12: “Experimental” vs. “Expected” PFCA leaching rates from composite carpet samples to landfill leachate at temperature 15oC, pH 6 and rotation speed 8 rpm. Parity line is shown to facilitate comparison. In addition to the differences observed between “expected” and “experimental” PFC leaching rates from composite carpets to landfill leachate, which were probably due to synergistic effects between individual carpets in composite samples, the percentage of initial PFCs in the individual and composite carpets appearing in the landfill leachate after 6 h contact at pH 6, temperature 15oC and a rotation speed 8 rpm apparently differed, as shown in Figure 4.13. Since PFCA levels in carpet N8 were close to or below their MDL, their corresponding percentages are excluded from Figure 4.13. The percentages were determined from the following procedure:  !!  [Blank-corrected PFCA concentration in leachate after contacting with the carpet for 6 h] × leachate vol. ×100(%) Initial concentration of PFCA in carpet × carpet weight  !  !  91  N4  Analyte percentage leached to landfill leachate (%)  400  N5 N6 N7 Composite  300  200  100  0  Figure 4.13: Percentage of initial PFCAs on different carpets appearing in landfill leachate after 6 h contact at pH 6, temperature 15oC and rotation speed 8 rpm.  !  92  Percentages observed for PFBA in N4, N5 and N7, and for PFPA in N7 in Figure 4.13 exceed 100%. These unusual percentages are probably due to low initial concentrations of PFBA in N4, N5 and N7, and PFPA in N7, making the denominator of the above equation low compared to the numerator and resulting in high percentages. These close-to-MDL concentrations are not sufficiently accurate to draw valid conclusions. For other PFCAs, the observed percentages for N7 and N4 were greater than for N5 and N6. Furthermore, the percentages for composite carpet samples were low enough to confirm the observed trend of lower “experimental” concentrations than “expected” concentrations for composite carpets (See Figure 4.12). Various methods of PFC treatment application on carpet surface could be a possible reason for the observed differences. In addition, dust may be a significant source of PFCs (Liu et al. 2011), especially for carpets N6 and N7, which were very dusty. The observed leaching rates in these carpets could indicate partitioning from the dust particles into the leachate, in addition to leaching from fibres. Moreover, since adsorption/desorption appear to have played a dominant role in determining the overall mass exchange between carpets and leachate except for PFTA, occupation of the adsorption sites on carpet samples by dust particles might have affected the leaching rates. 4.5.7 Leaching rates of PFCs to leachate compared to distilled water PFC leaching rates from composite carpets to landfill leachate and distilled water at pH of 5, 6, 7 and 8 at 15oC are summarized in Table 4.13 for a rotation speed of 8 rpm and contact time of 6 h. Note that PFC concentrations for landfill leachate are corrected by concentrations of corresponding PFCs in the original leachate (with no carpet present) after 6 h at 15oC. Concentrations displayed in Table 4.13 are the mean values of tests conducted in duplicate.  !  93  Table 4.13: PFC concentrations leached from composite carpet samples to both leachate and distilled water with pH of 5, 6, 7 and 8 after 6 h contact at temperature of 15oC and rotation speed of 8 rpm. Tabulated concentrations are final concentrations in leachate after correcting for concentration of PFCs in leachate with no carpet and identical time, temperature and rotation speed, displayed in the last row. pH  Parameter  Leachate (ng/mL) 5 Water (ng/mL) Leachate (ng/mL) 6 Water (ng/mL) Leachate (ng/mL) 7 Water (ng/mL) Leachate (ng/mL) 8 Water (ng/mL) Blank leachate after 6 h (ng/mL)  !  PFBA  PFPA PFHxA PFHpA PFOA  PFNA  PFDA PFUnA PFDoA PFTA  PFBS  PFHxS  PFOS PFDS FOSA  0.061  0.323  1.025  1.442  0.416  0.526  0.382  0.132  0.363  0.700  0.000  0.009  0.015  0.000 0.002  0.081  0.857  1.316  2.197  0.500  1.000  0.586  0.103  0.250  0.606  0.000  0.017  0.089  0.003 0.001  0.054  0.288  1.227  1.509  0.426  0.656  0.447  0.123  0.312  0.695  0.000  0.011  0.027  0.000 0.003  0.071  0.989  1.316  1.973  0.468  1.037  0.632  0.130  0.217  0.474  0.011  0.012  0.077  0.002 0.002  0.140  0.226  1.349  1.791  0.496  0.746  0.501  0.177  0.307  0.715  0.001  0.023  0.028  0.000 0.002  0.087  0.853  1.263  1.929  0.429  1.013  0.603  0.129  0.204  0.551  0.000  0.013  0.071  0.002 0.001  0.089  0.141  0.984  1.356  0.387  0.648  0.460  0.169  0.238  0.475  0.005  0.006  0.024  0.000 0.089  0.076  0.865  1.438  2.107  0.469  1.121  0.636  0.161  0.142  0.345  0.000  0.020  0.078  0.002 0.002  0.087  0.434  0.273  0.106  0.044  0.191  0.015  0.004  0.006  0.011  0.001  0.055  0.063  0.002 0.000  94  Two approaches are taken in this section to compare the leaching rates into landfill leachate and into distilled water: First, leaching rates in both media are compared to determine the overall correlation between leaching into leachate and distilled water and to determine whether or not the relationship is pH-dependent. Second, leaching rates of different PFCs are compared one-by-one at different pH values to rule out species-specific correlations between leaching rates into landfill leachate and into distilled water. Since the PFC concentrations in the original landfill leachate (with no carpet present) changed with time, it is essential to use blank-corrected PFC concentrations in order to compare the leaching rates into landfill leachate and distilled water (See Section 4.5.6 for blank-correction procedure). Figure 4.14 displays concentrations of different PFCAs in distilled water after 6 h contact with composite carpet samples at temperature of 15oC, rotation speed of 8 rpm and different values of pH plotted against the blank-corrected PFCA concentrations in landfill leachate under identical contacting conditions. Leaching data for perfluorinated sulfonates are excluded in Figure 4.14 because of their very low concentrations. Parity lines are shown to aid the comparison. Distilled water appears to have a higher tendency to leach the PFCs than landfill leachate at pH 5 and pH 8. On the other hand, for a pH of 6 and 7, the leaching rates to landfill leachate tended to be higher.  !  95  (b)  pH=5  pH=6  2.5  PFCA leached to distilled water (ng/mL)  PFCA leached to distilled water (ng/mL)  (a)  2.0 1.5 1.0 0.5  2.0 1.5 1.0 0.5 0.0  0.0 0.0  0.5 1.0 1.5 PFCA leached to leachate (ng/mL)  0.0  2.0  (d)  pH=7  pH=8 PFCA leached to distilled water (ng/mL)  1.5 1.0 0.5 0.0 0.5  1.0  (c)  2.0  0.0  0.5  1.0  1.5  PFCA leached to leachate (ng/mL)  1.5  2.0  PFCA leached to leachate (ng/mL)  2.5 PFCA leached to distilled water (ng/mL)  2.5  2.0  2.5 2.0 1.5 1.0 0.5 0.0 0.0  0.5  1.0  1.5  2.0  PFCA leached to leachate (ng/mL)  ! Figure 4.14: PFCA concentrations in distilled water versus blank-corrected PFCA concentrations in landfill leachate after 6 h contact with composite carpet samples at 15oC, rotation speed of 8 rpm and (a) pH=5, (b) pH=6, (c) pH=7, (d) pH=8. Parity lines are shown to aid comparison. Figure 4.15, displays blank-corrected PFCA concentrations in landfill leachate and distilled water for different solution pHs. Compounds are again arranged along the x-axis in order of increasing number of carbon atoms in the fluorinated chain. In most cases, more lowermolecular-weight PFCAs (i.e. PFBA, PFPA, PFHxA, PFHpA, PFOA, PFNA, and PFDA) transferred to distilled water than to landfill leachate. This trend appeared to be reversed for  !  96  the higher-molecular-weight compounds, with PFUnA being the transition compound where concentrations were similar. Since the concentrations of PFCAs of lower molecular weight in blank leachate were greater than those of the PFCAs of higher molecular weight (see Table 4.13), the concentration driving force for analyte transfer in landfill leachate was lower for low-molecular-weight compounds in this study, resulting in less transfer into landfill leachate than into distilled water for lower-molecular-weight PFCAs. This might be the reason for the witnessed trend change for PFCAs of higher molecular weight than PFUnA. Note that the trend discussed above was clear for solution pH of 5, 6 and 8. For pH 7, however, no specific trend was observed, as shown in Figure 4.15 (c). Another reason for the difference in PFC leaching rates to landfill leachate and distilled water might be due to leachate impurities. Organic and inorganic matter, humic substances, surfactants and solvents, which are known to be present in landfill leachate, might influence the leaching of PFCs. Among perfluorinated sulfonates, PFHxS and PFOS are discussed. Like PFCAs, the maximum blank-corrected PFHxS concentration in landfill leachate was observed at pH 7, as shown in Figure 4.16 (a); at pH 5 and 8, levels of PFHxS in distilled water were significantly higher than in blank-corrected leachate, and at pH 6, these levels were almost equal. For PFOS, displayed in Figure 4.16 (b), analyte concentrations in distilled water were higher than blank-corrected concentrations in landfill leachate at all pHs examined.  !  97  (a) pH = 5  (b) pH = 6  Leachate  2.5  Distilled water  2.0 1.5 1.0 0.5  Concentration (ng/mL)  Concentration (ng/mL)  2.5  0.0  1.5 1.0 0.5 0.0  (d) pH = 8  (c) pH = 7  2.5  2.5  Concentration (ng/mL)  Concentration (ng/mL)  2.0  2.0 1.5 1.0 0.5  2.0 1.5 1.0 0.5 0.0  0.0  !!  ! 4-6 carbon PFCAs  7-9 carbon PFCAs  10-13 carbon PFCAs  4-6 carbon PFCAs  7-9 carbon PFCAs  10-13 carbon PFCAs  Figure 4.15: PFCA concentrations in distilled water and blank-corrected landfill leachate after 6 h contact with composite carpet samples at 15oC, rotation speed of 8 rpm and (a) pH=5, (b) pH=6, (c) pH=7 and (d) pH=8.  !  98  (b) PFOS 0.1  0.025  Concentration (ng/mL)  Concentration (ng/mL)  (a) PFHxS  0.02 Leachate  0.015 0.01  Distilled water  0.005 0  0.08 0.06 0.04 0.02 0  5  6  7 pH  8  5  !  6  7  8  !  pH  Figure 4.16: (a) PFHxS and (b) PFOS concentrations in distilled water and blankcorrected landfill leachate after 6 h contact with composite carpet samples at 15oC, rotation speed of 8 rpm and solution pH of 5, 6, 7 and 8.  !  99  Chapter 5: Conclusions and Recommendations 5.1 Conclusions The major findings from the analysis of perfluorinated compounds in carpet and landfill leachate/distilled water samples before and after contacting experiments may be summarized as follows: • Used and unused carpet samples manufactured in 2005 and before contained significant amounts of PFCs. Carpet samples manufactured in 2005, five years after the voluntary phase-out of PFOS manufacturing by the 3M Company in 2000 and three years after discontinuing PFOS manufacture in Canada in 2002, contained negligible PFOS. However carpets manufactured in 2000 and before (prior to PFOS ban) contained substantial amounts of both perfluorinated carboxylic acids and sulfonates. • PFHxA was the dominant PFC in raw landfill leachate, comprising ~38.0% of the total. PFNA and PFOS were also strongly present, representing ~22.4% and ~9.5% of the total PFCs in leachate respectively. • A notable increase in concentration of PFCAs in leachate samples was observed from 1 to 168 h of contact between composite carpet samples and leachate. Differences between 1 and 24 h were much greater than between 24 and 168 h of contact time. Concentrations of several PFCAs in this study stayed nearly constant between 24 and 168 h, suggesting that an equilibrium was reached between PFCs in carpets and landfill leachate. • Perfluorinated sulfonates underwent a decrease in leaching from 2 to 168 h contacting time due to reverse mass transfer, i.e. analyte transfer from leachate to carpet samples. An increase in concentrations of these compounds in carpet samples between 6 and 168 h of contacting with landfill leachate confirmed this finding. !  100  • Increasing the temperature from 5 to 35oC notably increased the transfer rates of most PFCs between carpet samples and landfill leachate. • The leaching rates of most PFCs increased, followed by a decrease, with leachate pH increasing from 5 to 8. The maximum leaching rates were detected at pH of 7 for most PFCs, while a few reached maxima at a pH of 6. • Except for PFTA, rotation had little or no effect on leaching rates, suggesting that the leaching rates were dependent on some factor (e.g. adsorption or desorption) other than external mass transfer. • The leaching rates of PFTA increased significantly due to rotation, suggesting that external mass transfer was the major contributor to the overall mass exchange of PFTA between carpets and leachate. • The overall leaching rates of PFCs into distilled water were somewhat higher than into landfill leachate. • Transfer of PFCAs with molecular weights lower than PFUnA (i.e. from PFBA with molecular weight of 214 g/mol to PFUnA with molecular weight of 564 g/mol) to distilled water was greater than to landfill leachate. For higher-molecular-weight PFCAs (i.e. PFDoA and PFTA with molecular weight of 714 g/mol) the trend reversed. Assuming that the major mass transfer mechanism for PFCAs leaching was based on the concentration driving force, greater concentrations of lower-molecular-weight PFCAs in blank leachate resulted in lower concentration driving forces, explaining why the leaching rates of these PFCAs to distilled water was higher than for landfill leachate. •  Mass balances applied to six leaching tests displayed net PFC outputs of 12 to 32% lower than net inputs in the leaching experiments. This could be due to dislodgement of dust  !  101  particles from carpets, especially from carpets N6 and N7 (old and dusty carpets), which might settle in the leachate sampling tubes or separate from leachate samples through filtration, and result in under-estimation of the final PFC concentrations in landfill leachate or distilled water samples.  5.2 Recommendations Key recommendations for future work are as follows: • The data provided in this study were preliminary. In addition, no information was available in the literature for comparison. These gaps should be filled by future work in order to obtain a better understanding of PFCs leaching from consumer products to landfill leachates and ultimately to groundwater. • In order to obtain better consistency in the results, more standardized methodologies for the analysis of PFCs as well as sample extraction and clean-up should be utilized in the future. Also it would be useful to include PFC precursors, especially fluorotelomer alcohols, in the analysis in order to keep track of generation or consumption of different PFCs through degradation pathways. • In this study, the number of tests was limited. Obtaining further data for effect of different factors on PFC leaching rates in future would be useful to derive more reliable conclusions. • Extending the time range for contact between carpets and leachate in future would be beneficial, as it would help to estimate the time required for each PFC to reach equilibrium. Also extending the contact time would be helpful in estimating long-term PFC leaching rates in landfills. • Further analysis of other landfill leachate constituents that possibly affect the PFC leaching !  102  rates into aqueous media would help to shed light on the agents contributing to different leaching rates into leachate and distilled water. • Experiments should be designed to measure the equilibrium concentrations of PFCs in landfill leachate at different temperatures, in order to facilitate the application of Arrhenius law on leaching rates to determine the temperature-dependence of PFC leaching. • Dust particles might be a significant source of PFCs. 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To figure out whether the dominant resistance is on the outside or inside of the vessel, the Biot modulus is calculated as follows: Biot modulus = Bi =  !! !  (A.1)  h : Natural convection heat transfer coefficient for air, ~ 25 W/m2.oC (Holman 1976) s : Characteristic dimension of the body, which is equal to half-thickness for a plate. Since the vessel could be assumed as a plate with thickness of 34 mm, s = 34/2 = 17 mm = 0.017 m. k : Thermal conductivity of the vessel. According to AK Steel Corporation (2007), for stainless steel 316, k is ~ 16.2 W/m.oC. The Biot modulus from Equation (A.1) is: Bi =  !"#!×!!.!"#! !".!  = 0.026  (A.2)  Very low values for Biot number (i.e. less than 0.1) indicate negligible internal-conduction resistance in comparison with surface-convection resistance (Holman 1976). With this assumption, Equation (A.3) represents heat transfer between liquid and its surrounding air, based on the “lumped capacitance” method. Note that this method is utilized when the temperature changes uniformly under a cooling or warming convective flow, i.e. temperature gradients are negligible inside the object. hair A (Tatm-Tliq) dt = ( Mvessel Cpvessel + Mliq Cpliq) dT  !  (A.3)  117  The constant values in the Equation (A.3) are discussed below. Note that the calculated numbers are based on one vessel. Convection Heat Transfer Coefficient for Air: According to Holman (1976), the natural convection heat transfer coefficient for air (hair) is 5-25 W/m2.oC in case of free convection. Since there was air movement when the doors where opened, and it is a “worst-case value”, hair has been assumed to be 25 W/m2.oC. Surface Area of Vessel: Each vessel is divided into three regions and the surface area for each region has been calculated separately. Figure A.1 shows a side-view of a single vessel.  Figure A.1: Side-view of a single vessel AMain cylinder: Π. 900. 82. 10-6 = 231.73 x 10-3 (m2) ATop end:  {[Π. (150)2/4] + [Π. 28. 150] + [Π. (1502 – 822)/4]} x 10-6 = 43.24 x 10-3 (m2)  ABottom end: {[Π. (82)2/4] + [Π. 14. 150] + [Π. (1502 – 822)/4]} x 10-6 = 24.26 x 10-3 (m2) ATotal :  !  (231.73 + 43.24 + 24.26) x 10-3 = 299.23 x 10-3 (m2)  118  Vessel Mass: The mass of a single vessel has been measured by a scale and equals to 18.1 kg. The vessel ends were included in measuring the weight. Cp of Vessel: The specific heat capacity of Stainless Steel 316 in the range of 0-100oC is 0.50 kJ/kg.oC (AK Steel Corporation 2007). Liquid Mass: Since the vessels were filled up to 80% of their capacity in all experiments, the Mliq ≈ 4 kg. Cp of Leachate: It is assumed that the specific heat capacity of leachate is similar to water (Cpliq = 4.2 kJ/kg.K). Substituting these numbers simplifies equation (A.3) to: !!"# !"!!"# !!!"#!! (!!"#!!!"#)  = 4.75 x 10-4  (A.4)  Finally differentiation from equation (A.4) results in: Ln!  (!!"#!!!!!!"#)! (!!"#!!!!!"#)!  = 4.75 x 10-4 t  (A.5)  Note that the initial condition for temperature is as follows: at t1 = 0 , Tliq = T1 liq (initial liquid temperature) Solving Equation (A.5) for liquid temperature as a function of time: Tliq = Tatm – [(Tatm – Tliq 1) (e -4.75 x 10^4 t )]  (A.6)  The final liquid temperature after a sudden temperature change in room temperature at a specific time could be calculated through Equation (A.6). In addition, the “thermal time constant”, which represents the time required for the system’s step response to reach ~63.2% of its final value in a lumped system is calculated as follows: Thermal time constant = [(Mvessel Cpvessel + Mliq Cpliq) / (hA)]  (A.7)  Substituting for the Mvessel, Cpvessel, Mliq, Cpliq, h and A from the previous part results in:  !  119  Thermal time constant = [(18.1 × 500 + 4 × 4200) / (25 × 0.299)] = ~3458 s = ~58 min Therefore, almost one hour is required for the vessel contents to reach ~63.2 % of the final temperature. This time constant suggests that the apparatus will not show short-term temperature fluctuations due, for example, to opening of a window or door, but that the temperature will stabilize to a new room temperature after several hours.  !  120  Appendix B: Preliminary test results The results for preliminary tests are summarized in this section. As noted in Chapter 3, these leaching tests were conducted with carpet fibre at temperature of 21± 2oC, pH of 7.1 and rotation speed of 8 rpm. The concentrations of different PFCs in leachate/distilled water after contacting with carpet fibre for 0.5, 1, 2, 4, 10, 24 and 72 h are summarized in Table B.2. Figure B.1 also shows the concentrations of different PFCs in leachate after contacting with carpet fibre for 0.5, 1, 2, 4, 10, 24 and 72 h. From Figure B.1, all PFCA concentrations underwent a rapid initial increase followed by a slower increase during the 72 h of contacting. Among the PFCAs of interest in this study, PFBA, PFHpA and PFOA appear to have approached an equilibrium, since minor concentration changes were observed between 1 and 3 days. PFPA and PFHxA were subject to notable concentration increases between 1 and 3 days, suggesting that they still need some more contact time to reach equilibrium. An unusual decrease in concentration was observed for PFNA between 1 to 3 days. Figure B.2 also shows the total concentrations of PFCAs in leachate after 0.5, 1, 2, 4, 10, 24 and 72 h contact with carpet fibre, suggesting that the total concentrations of PFCAs increased from 0.5 to 72 h. Concentrations of different PFCs in blank leachate samples after 0, 0.5, 24, and 72 h, at temperature of 21± 2oC, pH of 7.1 and rotation speed of 8 rpm, shown in Table B.2, suggest that concentrations of most PFCs underwent changes over time due to biodegradation of precursors present in landfill leachate. Figure B.3 compares the PFCA concentrations in blank-corrected landfill leachate and distilled water after 3 days of contact with carpet fibre at temperature of 21± 2oC, pH of 7.1 and rotation speed of 8 rpm.  !  121  Table B.1: Preliminary tests - concentrations of different PFCs in leachate/distilled water after contacting with carpet fibre for 0.5, 1, 2, 4, 10, 24 and 72 h. The experiments were conducted at temperature of 21± 2oC, pH of 7.1 and a rotation speed of 8 rpm. ! Media time (h)  Leachate /Fibre  Water /Fibre *  PFBA (ng/L)  PFPA PFHxA PFHpA PFOA (ng/L) (ng/L) (ng/L) (ng/L)  PFNA (ng/L)  PFDA PFUnA PFDoA PFTA (ng/L) (ng/L) (ng/L) (ng/L)  PFBS PFHxS PFOS (ng/L) (ng/L) (ng/L)  PFDS (ng/L)  *  0.5  645  1698  2192  1935  1292  1658  957  430  58  28  96  221  95  1  422  1881  3176  3810  1953  2000  1114  281  60  21  92  164  96  *  BMDL! *BMDL!  2  450  2130  3591  5129  2319  2743  1122  306  54  17  96  147  87  *  BMDL! *BMDL!  4  635  2716  5674  7163  3702  3505  2050  475  111  30  78  140  96  *  BMDL! *BMDL!  10  946  3802  6751  10445  4352  4874  1949  557  106  21  96  124  82  *  BMDL! *BMDL!  24  1370  5970  10034  16674  5949  6891  2116  683  96  16  84  82  64  *  BMDL! *BMDL!  72  1714  7589  13403  17294  5772  5900  1860  477  64  11  74  41  37  *  BMDL *BMDL  72  1173  6471  11401  16830  5711  7600  2649  1099  235  36  3  BMDL  35  *  BMDL *BMDL  *  1  FOSA (ng/L) BMDL  Below Method Detection Limit.  Table B.2: Preliminary tests - concentrations of different PFCs in blank leachate samples after 0, 0.5, 24, and 72 h, at temperature of 21± 2oC, pH of 7.1 and a rotation speed of 8 rpm.  0  PFBA (ng/L) 0  0.5  1  Leachate/ Fibre  Media time (h)  *  !  PFPA PFHxA PFHpA PFOA (ng/L) (ng/L) (ng/L) (ng/L) 146 272 495 154 220  312  539  148  PFNA (ng/L) 268 274  PFDA PFUnA PFDoA PFTA (ng/L) (ng/L) (ng/L) (ng/L) 16 11 4 0.5 17  14  1  *  PFBS PFHxS PFOS (ng/L) (ng/L) (ng/L) * BMDL 99 242  BMDL *BMDL  24  24  134  511  466  160  261  14  15  2  0.5  *  72  72  263  1084  556  190  323  19  18  2  0.4  *  123  BMDL  117  BMDL  126  PFDS (ng/L) 182  FOSA (ng/L) * BMDL  175  *  BMDL  246  190  *  BMDL  263  216  *  BMDL  237  Below Method Detection Limit.  122  ! ! 20000 PFHpA  18000  PFBA PFC Concentration (ng/L)  16000  PFPA  14000  PFHxA  12000  PFOA  10000  PFNA  8000 6000 4000 2000 0 0  10  20  30  40 Time (h)  50  60  70  80  ! Figure B.1: Concentrations of different PFCAs in leachate after contacting with carpet fibre for 0.5, 1, 2, 4, 10, 24 and 72 h. The experiments were conducted at temperature of 21± 2oC, pH of 7.1 and rotation speed of 8 rpm.  60000  Σ PFCAs (ng/L)  50000 40000 30000 20000 10000 0 0.5  1  2  4  10  24  72  Time (h)  Figure B.2: Summation of PFCAs in leachate after contacting with carpet fibre for 0.5, 1, 2, 4, 10, 24 and 72 h. The experiments were conducted at temperature of 21± 2oC, pH of 7.1 and rotation speed of 8 rpm.  !  123  !  18000 16000 14000  Concentration (ng/L)  12000 10000 8000  Water Leachate  6000 4000 2000 0  Figure B.3: Comparison of PFCA concentrations in blank-corrected landfill leachate and distilled water after 3 days of contact with carpet fibre at temperature of 21± 2oC, pH of 7.1 and rotation speed of 8 rpm.  !  124  Appendix C: Raw data and recoveries for carpet samples Table C.1: Raw data for carpet analysis for samples before and after contact with leachate or distilled water. Note that the experiments were conducted in triplicate, with tabulated values being the average of the three determinations. Weight (g)  PFBA (ng/g)  PFPA (ng/g)  PFHxA (ng/g)  PFHpA (ng/g)  PFOA (ng/g)  PFNA (ng/g)  PFDA (ng/g)  PFUnA (ng/g)  PFDoA (ng/g)  PFTA (ng/g)  PFBS (ng/g)  PFHxS (ng/g)  PFOS (ng/g)  PFDS (ng/g)  FOSA (ng/g)  1.00  75.21  74.37  83.98  89.38  87.69  84.32  104.55  101.18  71.92  86.85  61.97  72.43  81.62  75.13  96.96  1.00  113.37  93.00  90.35  80.96  78.92  90.35  100.97  106.29  73.52  89.46  72.81  79.36  87.95  70.95  115.15  1.00  94.34  91.89  93.30  80.00  89.53  100.00  118.87  112.26  76.60  100.94  69.25  70.38  96.23  81.70  122.64  Blk carpet 1  1.14  7.10  23.27  3.30  3.58  0.73  1.52  0.70  0.62  0.32  0.63  0.46  0.72  0.69  0.46  0.15  Blk carpet 2  1.24  6.54  21.43  3.04  3.30  0.67  1.40  0.65  0.57  0.30  0.58  0.43  0.66  0.63  0.42  2.81  Blk carpet 3  1.08  7.54  24.70  3.50  3.80  0.77  1.61  0.75  0.65  0.34  0.67  0.49  0.76  0.73  0.49  2.36  N4  3.88  12.37  170.10  165.72  324.74  58.76  188.66  93.81  21.47  29.90  20.03  0.14  0.21  1.54  0.14  0.07  N4-A  3.87  6.72  173.60  153.97  297.08  55.80  186.00  91.45  23.77  30.74  22.78  0.14  0.21  2.16  0.14  0.07  N4-B  3.80  8.05  171.80  162.06  284.14  59.19  182.32  90.24  22.23  29.99  22.60  0.14  0.22  2.29  0.14  0.08  N5  3.70  3.95  56.52  89.78  151.70  35.69  108.98  50.30  18.85  9.73  9.73  0.14  3.79  3.70  0.14  0.08  N5-A  4.24  5.29  57.84  100.33  142.12  38.48  99.86  56.66  19.19  10.48  13.64  0.12  5.34  4.77  0.12  0.07  N5-B  3.48  2.33  52.62  94.02  158.71  39.97  104.08  57.22  21.51  10.67  11.56  0.15  5.09  5.15  0.15  0.08  N6  1.83  10.08  115.62  215.34  149.04  121.64  138.63  267.40  79.45  165.48  304.66  8.49  0.68  95.34  0.29  14.03  N6-A  2.18  7.02  109.22  146.40  99.59  98.67  131.71  312.53  90.87  251.03  370.81  0.24  0.38  67.92  0.74  13.63  N6-B  1.97  8.50  81.93  150.13  119.59  90.08  107.38  240.71  73.79  124.68  199.49  0.27  0.04  66.67  2.04  13.74  N7  3.10  2.62  16.88  34.86  83.93  12.88  34.54  15.56  4.33  2.56  3.36  0.17  0.27  28.83  0.17  0.09  N7-A  3.81  2.13  6.98  33.61  38.34  7.25  24.26  10.82  3.94  1.68  2.78  0.14  0.56  28.36  0.14  0.08  N7-B  3.46  2.34  6.33  28.43  50.27  8.99  27.74  10.78  1.74  1.08  2.55  0.15  0.24  22.22  0.15  0.08  N8  3.16  2.57  8.41  1.19  1.29  0.26  0.55  0.25  0.22  0.12  0.23  0.17  0.26  3.51  0.17  0.09  Description Blank Carpet-1 (spiked) Blk Carpet-2 (spiked) Blk carpet-3 (spiked)  !  125  Table C.1 (Continued): Raw data for carpet analysis for samples before and after contact with leachate or distilled water. ! Description  Weight (g)  PFBA (ng/g)  PFPA (ng/g)  PFHxA (ng/g)  PFHpA (ng/g)  PFOA (ng/g)  PFNA (ng/g)  PFDA (ng/g)  PFUnA (ng/g)  PFDoA (ng/g)  PFTA (ng/g)  PFBS (ng/g)  PFHxS (ng/g)  PFOS (ng/g)  PFDS (ng/g)  FOSA (ng/g)  N8-A  3.87  2.09  6.86  0.97  1.06  0.21  0.45  0.21  0.18  0.10  0.19  0.14  0.21  2.71  0.14  0.07  N8-B  3.41  2.38  7.79  1.11  1.20  0.24  0.51  0.24  0.21  0.11  0.21  0.15  0.24  0.16  0.15  0.08  5.34  1.52  22.84  40.43  68.89  22.28  51.67  55.60  13.29  29.76  37.81  0.10  0.15  13.55  0.10  2.64  4.79  1.49  12.61  23.18  23.18  14.95  23.39  43.23  18.36  26.94  34.67  0.11  0.17  13.95  0.11  3.15  4.66  2.23  22.55  43.38  64.85  24.05  44.02  58.19  21.69  24.05  35.43  0.11  1.69  14.75  0.11  3.89  4.92  1.65  4.25  11.71  29.48  11.26  33.96  33.96  9.66  10.31  17.06  0.11  4.35  12.73  0.11  2.07  6.58  0.38  2.96  10.09  19.61  9.32  23.71  33.14  7.96  16.26  20.06  0.08  0.82  11.28  0.08  2.46  6.00  0.35  2.82  11.88  26.50  11.85  29.00  34.84  9.98  11.78  18.84  0.09  3.58  12.78  0.09  2.12  4.94  2.29  30.97  57.49  80.77  27.13  64.17  56.68  17.11  17.79  30.97  0.11  2.35  13.48  0.11  2.37  4.73  1.72  12.44  39.13  63.24  20.60  44.84  49.92  9.96  28.13  34.90  0.11  0.17  13.87  0.11  2.58  5.40  1.94  25.74  48.69  78.69  28.70  45.92  57.03  16.81  24.25  40.92  0.10  0.60  15.55  0.10  2.96  4.72  2.16  24.36  39.19  56.78  22.67  60.59  53.18  16.29  19.72  26.27  0.11  1.28  13.07  0.11  3.26  6.04  1.34  13.74  27.32  42.05  15.50  31.46  43.54  8.64  21.52  23.18  0.09  0.14  10.02  0.09  2.85  4.79  1.69  15.88  31.10  37.36  15.72  29.64  43.41  10.48  20.52  20.77  0.11  0.17  7.99  0.11  3.24  4.41  1.88  22.60  36.04  65.05  18.47  42.61  45.56  17.07  17.04  24.71  0.12  7.39  13.51  0.12  2.18  4.79  1.70  5.55  0.79  0.85  0.17  0.36  0.17  0.15  0.87  0.15  0.11  0.17  2.11  0.11  0.06  5.08  1.60  5.24  0.32  0.81  0.16  0.34  0.16  0.14  0.65  0.14  0.10  0.16  2.34  0.10  0.06  4.50  1.19  5.91  0.84  0.73  0.18  0.38  0.18  0.16  0.90  0.16  0.12  0.18  1.98  0.12  0.06  7.83  1.04  6.41  12.41  15.84  6.32  22.22  23.88  8.40  9.53  17.37  0.07  1.27  4.96  0.07  0.67  6.30  1.29  4.37  8.28  20.97  9.04  29.22  39.39  8.61  16.68  18.42  0.08  0.94  12.90  0.08  2.05  Rotation:0rpm Time: 6h Rotation:0rpm Time: 6h (A) Rotation:0rpm Time: 6h (B) Time:168 h Rotation:0rpm Time:168 h Rotation:0rpm(A) Time:168 h Rotation:0rpm(B) Time: 6h Temp: 5C Time: 6h Temp: 5C (A) Time: 6h Temp: 5C (B) Carpet contacted w/ N62, 6hr, 20C Distilled water pH:7 Distilled water pH:7 (A) Distilled water pH:7 (B) Carpet N8 Time:6h Carpet N8 Time:6h (A) Carpet N8 Time:6h (B) Time: 24 h Temp: 35 C Time: 24 h Temp: 35 C (A)  !  126  Table C.1 (Continued): Raw data for carpet analysis for samples before and after contact with leachate or distilled water. ! Weight (g)  PFBA (ng/g)  PFPA (ng/g)  PFHxA (ng/g)  PFHpA (ng/g)  PFOA (ng/g)  PFNA (ng/g)  PFDA (ng/g)  PFUnA (ng/g)  PFDoA (ng/g)  PFTA (ng/g)  PFBS (ng/g)  PFHxS (ng/g)  PFOS (ng/g)  PFDS (ng/g)  FOSA (ng/g)  4.77  1.70  3.38  8.85  20.48  9.36  30.84  37.98  8.75  19.87  22.45  0.11  1.12  12.32  0.11  2.41  5.50  1.48  4.11  9.21  21.11  8.79  24.93  35.30  8.30  18.09  20.01  0.10  0.67  9.39  0.10  1.97  6.38  1.27  3.93  7.43  18.96  5.64  18.33  18.02  4.59  10.37  23.03  0.08  1.80  4.04  0.08  1.44  Reagent Blank  1.00  8.11  26.57  3.77  4.09  0.83  1.73  0.80  0.70  0.37  0.72  0.53  0.82  0.79  0.53  0.29  Reagent Blank A  1.00  8.11  26.57  3.77  4.09  0.83  1.73  0.80  0.70  0.37  0.72  0.53  0.82  0.79  0.53  0.29  Reagent Blank B  1.00  8.11  26.57  3.77  4.09  0.83  1.73  0.80  0.70  0.37  0.72  0.53  0.82  0.79  0.53  0.29  Reagent Blank  1.00  8.11  26.57  3.77  4.09  0.83  1.73  0.80  0.70  0.37  0.72  0.53  0.82  0.79  0.53  0.29  5.25  1.57  18.55  46.14  59.29  23.64  54.91  57.39  19.45  35.65  67.30  0.10  1.14  12.53  0.10  2.23  4.58  1.17  24.23  33.84  58.28  22.92  53.92  57.41  13.38  33.40  38.64  0.12  0.18  17.11  0.11  3.36  4.72  1.72  5.63  0.80  0.89  0.18  1.00  1.06  0.51  0.48  0.76  0.11  0.17  0.14  0.11  0.06  6.04  1.34  13.74  27.32  42.05  15.50  31.46  43.54  8.64  21.52  23.18  0.09  0.14  10.02  0.09  2.85  4.79  1.69  15.88  31.10  37.36  15.72  29.64  43.41  10.48  20.52  20.77  0.11  0.17  7.99  0.11  3.24  4.41  1.88  22.60  36.04  65.05  18.47  42.61  45.56  17.07  17.04  24.71  0.12  7.39  13.51  0.12  2.18  Description Time: 24 h Temp: 35 C (B) Time: 24 h Temp: 35 C (C) Time: 24 h Temp: 35 C (D)  Time:6 h Temp: 20C Time:6 h Temp: 20C (A) Time:6 h Temp: 20C (B) Distilled water pH:7 Distilled water pH:7 (A) Distilled water pH:7 (B)  ! ! !  !  127  Table C.2: Recovery percentages for carpet samples before contact. ! 13  13  C-PFHxA Accuracy (%)  13  C-PFOA Accuracy (%)  13  13  C-PFNA Accuracy (%)  13  Sample Name  C-PFBA Accuracy (%)  C-PFDA Accuracy (%)  C PFOS Accuracy (%)  N4-A  68  142  243  157  152  173  N4-B  73  126  241  136  123  149  N4-C  87  152  264  161  156  154  Mean (N4)  76  140  249  151  144  159  S.Dev (N4)  10  13  13  13  18  13  N5-B  100  150  175  143  172  133  N5-A  126  166  218  169  186  165  N5-C  57  54  63  55  52  61  Mean (N5)  94  123  152  122  137  119  S.Dev (N5)  35  60  80  60  74  53  N6-A  138  142  159  159  162  155  N6-B  58  45  67  53  53  61  N6-C  130  120  152  189  144  154  Mean (N6)  109  102  126  134  120  123  S.Dev (N6)  44  51  52  71  58  54  N7-A  175  173  195  148  198  179  N7-B  183  152  212  167  195  242  N7-C  264  179  251  216  240  173  Mean (N7)  207  168  219  177  211  198  S.Dev (N7)  49  14  29  35  25  38  N8-A  158  200  145  88  64  132  N8-B  138  140  126  80  61  104  N8-C  64  53  66  64  63  64  Mean (N8)  120  131  112  77  63  100  S.Dev (N8)  50  74  41  12  2  34  Table C.3: Efficiencies for extraction of different PFCs from carpet samples. Sample No. PFBA PFPA PFHxA PFHpA PFOA PFNA PFDA PFUnA PFDoA PFTA PFBS PFHxS PFOS PFDS FOSA *  E.E (%) N4  100  100  99  99  100  99  99  100  100  100  100  100  95  100  100  E.E (%) N5  100  100  100  99  100  98  98  98  100  100  100  100  94  100  100  E.E (%) N6  100  100  98  98  100  98  98  97  98  99  100  100  99  100  100  E.E (%) N7  100  100  100  96  100  98  100  100  100  100  100  100  99  100  100  E.E (%) N8  100  100  100  100  100  100  100  100  100  100  100  100  99  100  100  !!!!!!!!!!!!!!!!!!!!!!!!!!!!*  !  Extraction Efficiency  128  Appendix D: Raw data, recoveries and characteristics of leachate samples Table D.1: Recovery percentages for leachate samples. 13 CPFBA 13CPFHxA 13CPFOA 13CPFNA 13CPFDA 13CPFOS Accuracy Accuracy Accuracy Accuracy Accuracy Accuracy (%) (%) (%) (%) (%) (%)  Media/Carpet  Sample ID  Time (h)  pH  Temp (oC)  Rot. speed (rpm)  Lab Blank 1  N/A  N/A  N/A  N/A  N/A  109  98  95.7  101  85.4  87.1  Lab Blank 2  N/A  N/A  N/A  N/A  N/A  130  99.4  99.5  122  125  109  Lab Blank 3  N/A  N/A  N/A  N/A  N/A  129  96.5  121  128  135  119  Leachate Blank 1  N/A  N/A  N/A  N/A  N/A  80.5  73.5  113  129  127  97  Leachate Blank 2  N/A  N/A  N/A  N/A  N/A  57.8  52.2  89.7  106  102  75.3  Leachate Blank 3  N/A  N/A  N/A  N/A  N/A  59.2  55.2  93.6  107  111  77.8  Leach Spike 1  N/A  N/A  N/A  N/A  N/A  60.4  57.7  86.2  99  106  68.6  Leach Spike 2  N/A  N/A  N/A  N/A  N/A  51.8  55.4  97.7  105  103  74.3  Leach Spike 3  N/A  N/A  N/A  N/A  N/A  51.1  54.6  93.2  107  118  77.9  Leachate/Composite  L1  2  6  15  8  55.2  67  85.9  96.1  81.8  84.2  Leachate/Composite  L2  1  6  15  8  90.6  97.3  121  130  133  102  Leachate/Composite  L3  1  6  15  8  98.5  103  133  150  151  120  Leachate/Composite  L6  24  6  15  8  44.3  56  74.4  72.6  102  62.2  Leachate/Composite  L7  24  6  15  8  49.2  60.4  82.8  87.1  98.7  69.9  Leachate/Composite  L8  6  6  15  8  57.2  76.9  99.3  104  102  72.4  Leachate/Composite  L9  6  6  15  8  70.7  83.2  113  126  115  122  Leachate/Composite  L10  2  6  15  8  55.3  79.9  97.7  97.8  106  61.3  MeOH  MeOH  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  MeOH  MeOH  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  1 ppb  1 ppb  N/A  N/A  N/A  N/A  84.8  93.4  91.8  94.9  84.8  89  MeOH  MeOH  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  MeOH  MeOH  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  Leachate/Composite  L11  6  6  15  0  48.5  66.6  80.9  93  88.4  63  Leachate/Composite  L12  6  6  15  0  58.6  70.9  95.6  96.9  87.4  65.6  Blank Leachate  L13  168  6  15  8  58  57  81.4  89.6  77.3  61.7  Leachate/Composite  L14  168  6  15  8  32.4  57  80.4  86.7  81.6  50.7  Leachate/Composite  L15  168  6  15  8  52.5  80.2  100  107  101  67.5  Leachate/Composite  L16  6  7  15  8  48.4  74.4  90.7  104  90  67.4  Leachate/Composite  L17  6  7  15  8  27.2  52.3  70  66.9  59.7  50.3  Leachate/Composite  L18  6  5  15  8  53.4  71  122  111  98.7  67.7  Leachate/Composite  L19  6  5  15  8  64.6  64.4  86.6  80.1  63.2  48.3  Leachate/Composite  L20  6  6  15  8  40.6  92.8  128  130  120  81.7  Leachate/Composite  L21  6  5  15  8  120  128  132  125  96.7  92.9  Leachate/Composite  L22  6  6  15  8  54.1  76.7  93.8  100  95.8  62.5  Leachate/Composite  L23  6  8  15  8  54.7  84.8  104  106  102  93  !  129  Table D.1 (Continued): Recovery percentages for leachate samples.! !  !  !  Rot. 13CPFBA 13CPFHxA 13CPFOA 13CPFNA 13CPFDA 13CPFOS Temp speed Accuracy Accuracy Accuracy Accuracy Accuracy Accuracy (oC) (rpm) (%) (%) (%) (%) (%) (%)  Media/Carpet  Sample ID  Time (h)  pH  Leachate/Composite  L24  6  8  15  8  60.6  75.6  123  127  112  101  Leachate Blank  L25  6  6  15  8  75.7  88  128  138  119  96.5  Water/Composite  L26  6  7  15  8  119  138  132  121  106  123  Water/Composite  L27  6  8  15  8  64.9  101  99.4  96.5  80.3  60.9  Water/Composite  L28  6  5  15  8  121  131  137  129  98.2  76.5  Water/Composite  L29  6  8  15  8  92.5  143  129  117  104  85.2  Leachate Blank  L30  6  6  15  8  45.2  55.5  96  98.6  94.2  71.1  MeOH  MeOH  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  MeOH  MeOH  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  1 ppb  1 ppb  N/A  N/A  N/A  N/A  77.9  104  124  117  105  105  MeOH  MeOH  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  MeOH  MeOH  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  Water/Composite  L31  6  6  15  8  94.5  119  124  117  98.2  76.5  Water Blank  L32  6  N/A  15  8  66.8  97.5  96.5  103  83.7  79  Water/Composite  L33  6  6  15  8  113  139  134  127  106  77.6  Water/Composite  L34  6  7  15  8  88.2  158  142  130  105  77.6  Leachate Blank  L35  6  6  15  8  41.8  54.2  97.3  101  93.9  71.7  Leachate/Composite  L36  24  6  35  8  64.6  106  125  116  86.2  60.2  Leachate/Composite  L37  24  6  35  8  52.9  70.3  79.5  75.1  65.6  53.1  Leachate/Composite  L38  2  6  35  8  70.9  75.2  116  115  94  72.2  Leachate/Composite  L39  2  6  35  8  66.1  79.8  134  127  106  75.1  Leachate/Composite  L40  2  6  5  8  49.4  70.8  96.2  96  82.8  83  Leachate/Composite  L41  24  6  5  8  57.7  96.8  128  136  121  88.9  Leachate/Composite  L42  24  6  5  8  48.5  72.2  87.3  83.3  83.1  67.1  Leachate/Composite  L43  6  6  35  8  51.3  73.5  116  108  96.7  90.7  Leachate/Composite  L44  6  6  35  8  67.2  112  112  111  92.9  75.1  Leachate/Composite  L45  6  6  15  8  54  85.1  128  139  140  88.6  Leachate Blank  L46  6  6  15  8  46.5  64.8  100  113  105  80.5  Leachate/Composite  L47  6  6  5  8  74.6  90.5  135  128  99.7  88.5  Leachate/Composite  L48  6  6  5  8  80.9  72.3  124  114  84.2  82.1  Leachate/Composite  L49  2  6  5  8  53.2  71.8  94  96.2  96.8  74.3  Leachate/ N6  L50  6  6  15  8  69.4  64.6  89.2  94.1  87  71.8  Leachate/N7  L51  6  6  15  8  33.7  37  56.1  50.2  45.7  46.4  Leachate/N7  L52  6  6  15  8  43.5  47.2  57.2  56.5  50.7  47.2  Leachate/N8  L53  6  6  15  8  97.4  89.6  105  79.7  41.5  85  Leachate/N8  L54  6  6  15  8  122  119  141  91.6  57  51.6  !  130  Table D.1 (Continued): Recovery percentages for leachate samples. ! Rot. 13CPFBA 13CPFHxA 13CPFOA 13CPFNA 13CPFDA 13CPFOS speed Accuracy Accuracy Accuracy Accuracy Accuracy Accuracy (rpm) (%) (%) (%) (%) (%) (%)  Media/Carpet  Sample ID  Time (h)  pH  Temp (oC)  Leachate/N4  L55  6  6  15  8  55.8  123  123  111  76.4  98.7  Leachate/N4  L56  6  6  15  8  81.5  132  146  137  106  114  Leachate/N5  L57  6  6  15  8  54  68.4  103  108  103  78.2  Leachate/N5  L58  6  6  15  8  17.3  24.7  42.1  38.2  32.4  27.6  Leachate/ N6  L59  6  6  15  8  49.4  56.6  84.9  83.1  79  82.2  Leachate/ Composite  L60  6  6  15  4  60.4  87.3  112  106  109  120  Leachate/ N6  L61  6  6  20  8  77.4  59.6  120  112  82.5  72.7  Blank Leachate  L62  6  6  15  8  67.4  76.7  125  140  123  90.6  Leachate/ Composite  L63  6  6  15  4  48.5  53.5  79  80.8  75.7  67.5  !  131  Table D.2: Raw data for PFC amounts (ng) in leachate samples. Note that the sample IDs correspond to those introduced in Table D.1 (N.D. stands for non-detectable).  !  !  Sample ID  PFBA (ng)  PFPA (ng)  PFHxA (ng)  PFHpA (ng)  PFOA (ng)  PFNA (ng)  PFDA (ng)  PFUnA (ng)  PFDoA (ng)  PFTA (ng)  PFBS (ng)  PFHxS (ng)  PFOS (ng)  PFDS (ng)  FOSA (ng)  L1  2.78  25.2  59.4  66.7  20.5  31.9  16.3  5.97  11.4  17.3  N.D.  3.56  5.41  N.D.  0.0241  L2  N.D.  26.2  40.4  37  12.9  22.4  15.1  3.76  7.12  8.26  0.494  2.5  4.12  N.D.  0.0194  L3  N.D.  17.9  38.2  34.8  12.1  19.9  14.7  3.53  7.86  8.6  0.31  2.25  5.83  N.D.  0.0251  L6  5.62  58  93.9  93.7  27.9  41.4  17.8  7.9  12.6  19  N.D.  2.66  5.1  N.D.  0.126  L7  6.63  56.3  85.5  88.2  25.2  42  20.5  8.36  13.4  21.6  0.418  2.48  5.6  N.D.  0.125  L8  6.22  32  93.6  76.2  26.3  38.7  18.9  4.74  15.3  28.5  N.D.  2.91  6.32  N.D.  0.0342  L9  6.03  33.8  62.1  60.3  18.6  31  14.8  5.57  10  18.8  N.D.  2.25  3.62  N.D.  0.0208  L10  3.45  43.7  49.7  59.6  18.4  34.8  16.7  4.23  8.11  12.9  N.D.  3.27  5.13  N.D.  0.0287  MeOH  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  MeOH  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  1 ppb  4.1  3.8  3.97  4.17  4.16  4.05  4.37  5.42  4.81  5.68  4.06  4.23  4.18  3.69  4.46  MeOH  N.D.  N.D.  194  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  MeOH  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  L11  8.59  28.3  64.7  64.4  21.8  29.1  21.9  5.17  6.59  4.93  1.09  3.03  7.12  N.D.  0.0677  L12  9.33  26.6  49  62.8  19.4  31  23.7  5.25  7.31  5.75  N.D.  2.85  6.32  N.D.  0.0621  L13  3.04  28.3  16.7  6.25  5.87  0.895  1.23  0.531  0.865  1  0.503  3  3.2  N.D.  0.0424  L14  7.25  44.5  101  113  31  45.5  21.9  9.96  22.8  47.1  N.D.  2.58  4.92  N.D.  0.111  L15  7.9  37.7  102  97.9  28.7  41.4  18.8  8.06  15.9  33  N.D.  2.23  4.55  N.D.  0.0989  L16  10.5  29.7  72.6  81.3  23.4  40  21.1  7.28  12.9  32.6  N.D.  3.66  6.5  N.D.  0.0696  L17  9.6  27.3  77.6  90.4  25.6  45  25.5  9.11  15.5  33.3  0.357  3.55  7.56  N.D.  0.0893  L18  5.85  31.1  59.7  66.9  19.4  28.9  17.2  5.31  14.9  29.2  N.D.  2.88  8.53  N.D.  0.0709  L19  7.05  34.5  60.6  72.7  22.3  36  18.6  7.02  18.5  35.2  N.D.  3.03  4.95  N.D.  0.0774  L20  6.72  30.8  69.9  71.7  20.1  35.8  16.7  4.6  11.2  28.1  N.D.  3.06  4.53  N.D.  0.0502  !  132  Table D.2 (Continued): Raw data for PFC amounts (ng) in leachate samples. Note that the sample IDs correspond to those introduced in Table D.1 (N.D. stands for non-detectable).  !  !  Sample ID  PFBA (ng)  PFPA (ng)  PFHxA (ng)  PFHpA (ng)  PFOA (ng)  PFNA (ng)  PFDA (ng)  PFUnA (ng)  PFDoA (ng)  PFTA (ng)  PFBS (ng)  PFHxS (ng)  PFOS (ng)  PFDS (ng)  FOSA (ng)  L21  3.18  38.9  60.8  101  22.9  45.5  26.5  4.3  11.4  27.3  N.D.  0.643  3.46  0.18  0.0161  L22  5.83  33  72  77.3  23.4  42.6  25.9  7.11  18.2  37.3  N.D.  3.17  7.66  N.D.  0.154  L23  8.34  24  62.3  70.2  20.1  39.5  21.2  8.35  10.9  23.1  N.D.  3.09  5.76  N.D.  0.155  L24  7.37  25.9  56.2  63.7  19.5  37.6  22.3  7.54  11.5  21.6  0.684  2.66  5.26  N.D.  0.17  L25  2.52  15.3  9.33  4.52  3.93  0.491  0.892  0.197  0.323  0.447  N.D.  2.14  2.78  N.D.  N.D.  L26  4.05  39.9  55.2  82.2  20.1  47  28.1  5.83  9.52  25.2  N.D.  0.649  4.53  N.D.  0.0693  L27  3.68  41.4  71.7  101  23  53.3  31.8  7.8  6.74  18.1  N.D.  0.972  5.37  N.D.  0.127  L28  4.19  39.9  60.2  101  23.1  46.4  27.4  5.2  11.6  28.4  N.D.  0.894  3.94  N.D.  0.0347  L29  3.29  38.4  61  93.3  20.2  50  26.9  7.05  6.35  13.7  N.D.  0.857  3.78  N.D.  0.118  L30  6.54  30.9  18.8  14.3  8.42  7.26  5.74  1.93  1.88  1.35  N.D.  2.27  3.02  N.D.  0.0245  MeOH  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  MeOH  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  1 ppb  3.93  4.03  3.94  4.02  4.19  3.92  4.05  4.45  N.D.  6.24  3.92  3.99  4.06  2.49  3.9  MeOH  N.D.  N.D.  N.D.  80.5  22.9  38.6  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  MeOH  N.D.  N.D.  41.7  130  37.7  60.2  23.9  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  N.D.  L31  3.12  45.2  58.9  87.7  20.4  47.5  27.3  5.38  8.92  21.2  0.529  0.491  4.08  N.D.  0.0743  L32  N.D.  N.D.  N.D.  0.391  N.D.  0.174  0.02  0.01  0.183  0.335  N.D.  N.D.  N.D.  N.D.  N.D.  L33  3.5  47.3  61.7  96.8  23.4  49.5  31.8  6.75  11.4  23.1  0.47  0.618  4.63  N.D.  0.0997  L34  4.02  39  61.7  96.4  19.6  46.7  27.7  6.11  9.38  25.8  N.D.  0.589  3.59  N.D.  0.0537  L35  3.26  15.6  17.2  4.28  4.21  0.272  0.512  0.143  0.327  0.655  0.289  2.75  3.49  N.D.  N.D.  L36  12.7  45.9  111  137  32.5  49.1  23.8  8.92  13.9  37.2  N.D.  2.31  8.64  N.D.  0.0891  L37  9.99  49.1  106  134  36.6  57.4  25.5  11.5  17.2  47.6  N.D.  2.13  8.31  N.D.  0.124  L38  5.23  66.1  73  89.6  27.5  43.4  27  7.91  16.2  31.9  N.D.  3.28  6.04  N.D.  0.041  L39  4.29  67.1  71.9  87.7  25.2  46.2  25.5  7.79  16.1  34.5  N.D.  3.61  7.44  N.D.  0.0438  !  133  Table D.2 (Continued): Raw data for PFC amounts (ng) in leachate samples. Note that the sample IDs correspond to those introduced in Table D.1 (N.D. stands for non-detectable). ! Sample ID  PFBA (ng)  PFPA (ng)  PFHxA (ng)  PFHpA (ng)  PFOA (ng)  PFNA (ng)  PFDA (ng)  PFUnA (ng)  PFDoA (ng)  PFTA (ng)  PFBS (ng)  PFHxS (ng)  PFOS (ng)  PFDS (ng)  FOSA (ng)  L40  3.1  22.5  36.8  47.6  15.7  26.4  19.6  8.39  15.9  27.2  N.D.  3.6  5.23  N.D.  L41  1.11  34.8  51.7  69.3  20.5  31.7  11.5  4.35  12.2  36.4  0.585  2.78  3.27  0.373  0.00819  L42  3.34  38.7  59.6  78.3  22  38.5  15.4  5.5  19.5  43.4  N.D.  3.44  7.1  N.D.  0.0106  L43  6.4  48.5  74.1  82.8  23.6  43.7  20.9  6.44  12.8  28.6  0.542  2.04  7.13  N.D.  0.0362  L44  5.38  55.7  73.6  92.4  23.6  41.6  21.3  5.44  9.53  22.8  N.D.  2.54  5.67  N.D.  0.0249  L45  6.65  30  57.7  71  19.5  33.2  17  4.96  13.5  25.8  0.614  2.38  4.08  N.D.  0.0474  L46  5.61  25.1  16.1  5.32  4.55  0.792  0.477  0.196  0.251  0.577  N.D.  2.95  3.82  N.D.  N.D.  L47  1.54  31.3  39.3  54.5  16.4  23.2  14  3.85  12.8  32  N.D.  2.91  4.43  N.D.  0.016  L48  3.74  41  58.4  70.6  19.5  29.1  15.4  4.4  16.7  36.2  N.D.  3.26  6.36  N.D.  0.0109  L49  3.43  30.4  48.8  46.3  16.7  25.7  15  6.75  11.9  23.7  N.D.  3.37  5.08  N.D.  0.0423  L50  15.3  44.6  63.6  34.1  29.4  28.4  44.1  14.1  62.8  120  N.D.  3.32  10.2  N.D.  0.487  L51  13.2  44.7  34.4  42.9  12  15  5.77  1.95  1.87  3.93  N.D.  3.98  8.23  N.D.  N.D.  L52  16.2  44.4  30.1  28.6  9.34  11.9  4.79  2  1.88  3.77  N.D.  N.D.  6.65  N.D.  N.D.  L53  6.95  32.6  9.65  10.7  4.34  0.844  0.801  N.D.  2.89  9.45  N.D.  5.21  3.29  N.D.  N.D.  L54  3.69  28.2  13.6  6.66  2.93  0.479  0.224  N.D.  1.45  4.02  N.D.  4.87  2.2  N.D.  N.D.  L55  17  71.2  166  259  48.5  116  21  2.28  4.22  7.94  N.D.  3.91  1.99  N.D.  N.D.  L56  14.2  71.2  164  262  47.3  111  24.2  2.36  4.88  7.82  N.D.  3.87  2.33  N.D.  N.D.  L57  23.9  66.9  49.5  44.3  16.2  26.2  10.5  3.33  2.72  3.29  N.D.  2.43  2.14  N.D.  N.D.  L58  23.70  72.71  51.28  34.87  13.92  18.45  8.00  2.17  13.20  2.55  N.D.  2.27  1.58  N.D.  N.D.  L59  15.2  49.1  72.2  29.6  26.7  26.4  42.4  14.6  56.7  110  N.D.  2.9  9.01  N.D.  0.407  L60  13.2  32.2  77.7  80.1  23.3  38.9  19.7  6.87  11.3  26.7  N.D.  3.17  5.46  N.D.  0.0966  L61  6.48  105  72.8  72.8  20.8  37.4  18  5.63  16.2  41.1  N.D.  3.28  6.16  N.D.  0.00824  L62  5.89  5.45  7.55  5.56  4.32  1.3  1.58  0.88  0.752  0.857  N.D.  2.45  3.22  N.D.  0.00224  L63  11.9  34.6  78.5  88.2  26.1  40.1  20.9  8.03  15.4  32.1  N.D.  3.06  7.07  N.D.  0.102  !  !  134  Table D.3: Initial and final pH, Total Dissolved Solids (TDS) and electrical conductivity of leachate samples of different leaching experiments.  Leachate/Composite  Time (h) 1  Leachate/Composite  1  18  Leachate/Composite  2  17  Leachate/Composite  2  Leachate/Composite Leachate/Composite Leachate/Composite  Media/Carpet  !  Mean Rotation Temp. (oC) Speed (rpm) 18 8  1  (pH)i  3  2  (pH)f  (TDS)i 4(TDS)f 5(Cond)i (mg/L) (mg/L) (µs/cm) 680 743 1403  6  (Cond)f (µs/cm) 1500  5.94  6.35  8  5.95  6.34  679  752  1400  1517  8  5.95  6.45  675  734  1385  1485  17  8  5.98  6.48  674  745  1375  1502  6  17  8  5.98  6.35  661  759  1366  1528  6  17  8  6.01  6.39  663  774  1366  1557  24  15  8  6.03  6.48  676  797  1389  1605  Leachate/Composite  24  15  8  6.03  6.47  675  801  1387  1612  Leachate/Composite  168  14  8  5.9  6.38  690  815  1402  1650  Leachate/Composite  168  14  8  5.89  6.42  689  806  1401  1632  Blank Leachate  168  14  8  5.91  6.1  675  673  1372  1370  Leachate/Composite  6  15  0  5.9  6.16  686  748  1414  1511  Leachate/Composite  6  15  0  5.91  6.15  684  746  1410  1506  Leachate/Composite  6  15  4  5.90  6.18  679  734  1400  1510  Leachate/Composite  6  15  4  5.93  6.21  683  753  1410  1528  Leachate/Composite  6  16  8  6.04  6.25  659  783  1348  1575  Leachate/Composite  5  16  8  5.08  5.73  658  936  1346  1871  Leachate/Composite  5  16  8  5.07  5.75  661  925  1352  1845  Leachate/Composite  7  16  8  7.01  7.04  676  734  1381  1480  Leachate/Composite  7  16  8  6.99  6.99  678  743  1382  1497  Blank Leachate  6  16  8  6.06  6.29  670  670  1379  1355  Leachate/Composite  8  16  8  7.95  7.53  766  816  1564  1640  Leachate/Composite  8  16  8  8.05  7.48  723  781  1479  1573  Leachate/Composite  6  14  8  6.04  6.46  674  771  1386  1554  Water/Composite  5  15  8  4.95  6.5  33.3  131  71.7  273  Water/Composite  5  15  8  4.92  6.35  35  161  76.5  333  Water/Composite  6  15  8  5.92  7.02  0.9  83.6  3  175.2  Water/Composite  6  15  8  5.94  7.1  0.7  81.2  2.53  170.1  Water/Composite  7  14  8  7.01  7.43  0.4  76  1.96  161  Water/Composite  7  14  8  7.05  7.5  0.2  88  0.74  184  Water/Composite  8  14  8  8.05  7.32  0  102.8  0.54  215  Water/Composite  8  14  8  8.08  7.45  0  81.6  0.53  172  Blank Leachate  6  15  8  6.04  6.38  672  685  1384  1406  Leachate/N4  6  14  8  5.9  6.32  671  717  1399  1450  Leachate/N4  6  14  8  5.91  6.33  673  709  1403  1434  Leachate/N5  6  14  8  5.9  6.28  674  703  1406  1424  Leachate/N5  6  14  8  5.9  6.26  674  696  1405  1410  Leachate/N6  6  14  8  5.92  6.4  668  826  1390  1658  Leachate/N6  6  14  8  5.94  6.42  667  831  1388  1670  Leachate/N7  6  14  8  5.91  6.31  669  816  1392  1642  Leachate/N8  6  15  8  5.9  6.32  680  723  1412  1459  135  Table D.3 (Continued): Initial and final pH, Total Dissolved Solids (TDS) and electrical conductivity of leachate samples of different leaching experiments. Mean Rotation Temp. (oC) Speed (rpm) 15 8 8 15  3  (TDS)i 4(TDS)f 5(Cond)i (mg/L) (mg/L) (µs/cm) 679 729 1410 677 766 1391  6  Leachate/N8 Leachate/Composite  Time (h) 6 6  Blank Leachate  6  15  8  5.92  6.2  679  678  1410  1371  Leachate/Composite  6  5  8  5.92  6.27  676  746  1410  1544  Leachate/Composite  6  5  8  5.93  6.3  679  723  1416  1488  Leachate/Composite  2  5  8  5.91  6.13  676  735  1410  1532  Leachate/Composite  2  5  8  5.92  6.12  675  739  1406  1541  Leachate/Composite  24  5  8  5.91  6.24  677  793  1411  1650  Leachate/Composite  24  35  8  5.93  6.26  677  792  1411  1649  Leachate/Composite  6  35  8  5.94  6.36  691  796  1427  1607  Leachate/Composite  6  35  8  5.92  6.34  680  791  1402  1596  Leachate/Composite  2  35  8  5.91  6.25  667  765  1356  1542  Leachate/Composite  2  35  8  5.94  6.3  683  774  1386  1561  Leachate/Composite  24  35  8  5.93  6.37  679  792  1385  1601  Leachate/Composite  24  35  8  5.92  6.38  682  781  1392  1579  Blank Leachate  6  20  8  6.01  6.22  685  678  1420  1369  Blank Leachate  6  6.19  686  690  1417  1411  Media/Carpet  8  1  (pH)i 5.93 6.03  2  (pH)f 6.28 6.47  35 5.94 Initial pH measured before starting the experiment. 2 Final pH measured at the end of the experiment. 3 Initial Total Dissolved Solids (TDS) measured before starting the experiment. 4 Final Total Dissolved Solids (TDS) measured at the end of the experiment. 5 Electrical Conductivity measured before starting the experiment. 6 Electrical Conductivity measured at the end of the experiment.  (Cond)f (µs/cm) 1471 1544  1  !  !  136  

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