Perinatal exposure to persistant organic pollutants implications for human health

PERINATAL EXPOSURE TO PERSISTENT ORGANIC POLLUTANTS: IMPLICATIONS FOR HUMAN HEALTH TAN JING NATIONAL UNIVERSITY OF SINGAPORE 2008 PERINATAL EXPOSURE TO PERSISTENT ORGANIC POLLUTANTS: IMPLICATIONS FOR HUMAN HEALTH TAN JING (B.Eng., Wuhan University, China) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF CHEMICAL AND BIOMOLECULAR ENGINEERING NATIONAL UNIVERSITY OF SINGAPORE 2008 I would like to dedicate this thesis to my parents, family, and xiaobai Acknowledgements ACKNOWLEDGEMENTS First and foremost, I would like to express my deep and sincere gratitude to my supervisor, A/P Jeffrey P. Obbard, from the Division of Environmental Science and Engineering, National University of Singapore, for his guidance, support and encouragement all along my work. His scientific spirit, uprightness, dedication and cheerfulness have been greatly inspirational to me. It is his constructive criticisms and numerous corrections in my manuscripts getting the thesis in present form. Furthermore, I wish to express my heartfelt gratitude to Dr. Annamalai Loganath and Dr. Chong Yap Seng from the Department of Obstetrics and Gynecology, for providing laboratory facilities, offering help in volunteer recruitment and the valuable scientific advice in this work. And all these work would not have been possible without the volunteers who donated their blood, tissues, and house dust. I wish to thank all the participants, and the hard-working nurses-- Ms. Janie Foo and Ms. Lee Siew Yee for their help on sample collection. This study also benefited from valuable technical support of research group members of A/P Jeffrey P. Obbard. Special thanks must also go out to Li Qingqing who has been an excellent guider patiently assisting me through the research methodology and experimental techniques at the beginning of this work. I also want to sincerely thank Tan Yen Ling, Xiao Man, Ma Lingling, Zhang Jie, Stephane Bayen, Oliver Wurl for their very suggestion and inspiration, and Marvin Joseph Fonacier Montefr, Mathew i Acknowledgements Sini, Doan Thi Thai Yen, Dang The Cuong, Subramanian Karuppiah for their personal and technical support. The contribution of Cheng Si Min and Lin Wei Xiong, who have assisted me during their Final Year Project, is not forgotten. A special acknowledgement is given to Dr. Gong Yinhan from the Tropic Marine Science Institute for his help in bioassay study (even though the data are not in use here), and Dr. Tomas Gareth, and Prof. Kevin C. Jones, who helped me a lot during my training in the department of Environmental Science, Lancaster University in 2005. I am deeply grateful to the Ministry of Education of Singapore, the National University of Singapore for providing scholarship and offering the facilities for this PhD program. I also wish to thank the National Medical Research Council of Singapore for the financial support of the project. I would also like to acknowledge all the staff and technical personnel for facilitating the administrative aspects of my research! Last but not least, I am deeply indebted to my parents, family, and husband whose patient love and sustained encouragement enabled me to complete this work. ii Table of Contents TABLE OF CONTENTS ACKNOWLEDGEMENTS I TABLE OF CONTENTS .III SUMMARY VIII LIST OF TABLES XI LIST OF FIGURES .XIII NOMENCLATURE . XIV CHAPTER INTRODUCTION AND OBJECTIVES . 1.1 INTRODUCTION 1.2 RESEARCH OBJECTIVES . CHAPTER LITERATURE REVIEW 2.1 INTRODUCTION TO POPS . 2.2 ENVIRONMENTAL BEHAVIOR OF POPS 12 2.3 HUMAN EXPOSURE TO POPS . 14 2.3.1 Exposure pathways . 14 2.3.2 Prevalence of POPs in humans . 15 2.3.3 Perinatal exposure to POPs 17 2.3.4 Toxicological effects of POPs on humans 17 2.4 POPS IN SINGAPORE 18 2.5 ANALYSIS OF POPS 22 iii Table of Contents 2.5.1 Extraction of POPs . 22 2.5.2 Cleanup of extracts . 25 2.5.3 Gas chromatography separation and mass spectrometry detection . 27 2.5.4 Quality assurance/quality control . 29 CHAPTER GENERAL MATERIALS AND METHODS 34 3.1 SUBSTANCES ANALYZED . 35 3.2 SAMPLE COLLECTION AND STORAGE . 36 3.3 CHEMICAL ANALYSIS 37 3.3.1 Materials . 37 3.3.2 Extraction 38 3.3.3 Lipid determination . 40 3.3.4 Cleanup . 41 3.3.5 Analysis by gas chromatography coupled with mass spectrometry 43 3.4 QUALITY ASSURANCE/ QUALITY CONTROL . 44 3.4.1 Method validation . 44 3.4.2 QA/QC during sample preparation 45 3.4.3 Quality assurance for GC-MS analysis 45 3.5 STATISTICS ANALYSIS . 46 3.5.1 Descriptive statistics . 46 3.5.2 Multivariate data analysis 46 CHAPTER MULTIVARIATE DATA ANALYSES OF PERSISTENT ORGANIC POLLUTANTS IN MATERNAL ADIPOSE TISSUE IN SINGAPORE . 50 iv Table of Contents 4.1 INTRODUCTION 50 4.2 RESULTS AND DISCUSSION . 53 4.2.1 Variables from questionnaires 53 4.2.2 Concentrations of POPs . 56 4.2.3 Multivariate data analysis 59 4.3 CONCLUSIONS 70 CHAPTER TRANSPLACENTAL TRANSFER OF PERSISTENT ORGANIC POLLUTANTS AND THE PRENATAL EXPOSURE IN SINGAPORE 72 5.1 INTRODUCTION 72 5.2 SAMPLE INFORMATION 73 5.3 RESULTS AND DISCUSSION . 75 5.3.1 Levels of OCP, PCB and PBDE in fetal and maternal compartments . 75 5.3.2 Model of PLSR 82 5.3.3 Influential factors on TPT of POPs 85 5.3.4 The placenta: a surrogate for prenatal exposure assessment? 87 5.4 CONCLUSIONS 89 CHAPTER EXPOSURE TO PERSISTENT ORGANIC POLLUTANTS IN UTERO AND THE BIRTH OUTCOMES 90 6.1 INTRODUCTION 90 6.2 SAMPLE INFORMATION 92 6.3 RESULTS AND DISCUSSION . 94 6.3.1 Levels of OCP, PCB and PBDE in cord blood . 94 6.3.2 Models constructed . 99 v Table of Contents 6.3.3 Baby head circumference, length and Birth weight 103 6.3.4 Apgar score . 105 6.3.5 Baby gender 106 6.4 CONCLUSIONS 109 CHAPTER PERSISTENT ORGANIC POLLUTANTS IN BREAST MILK IN SINGAPORE: INFLUENTIAL FACTORS AND THE HEALTH RISKS OF INFANTS………………………………………………………………………… 111 7.1 INTRODUCTION 111 7.2 SAMPLE INFORMATION 112 7.3 RESULTS AND DISCUSSION . 114 7.3.1 Levels of POPs in breast milk . 114 7.3.2 Results of the partial least-squares regression analysis . 121 7.3.3 Factors affecting the transfer of POPs to breast milk 122 7.3.4 Health risk of breastfed infants . 129 7.4 CONCLUSIONS 131 CHAPTER PERSISTENT ORGANIC POLLUTANTS IN HOUSE DUST IN SINGAPORE AND THE HEALTH RISKS . 132 8.1 INTRODUCTION 132 8.2 MATERIALS AND METHODS . 134 8.2.1 Sample collection 134 8.2.2 Materials . 136 8.2.3 Chemical analysis . 137 8.2.4 Quality assurance/ Quality control . 137 vi Table of Contents 8.2.5 Statistical analysis 138 8.3 RESULTS AND DISCUSSION . 138 8.3.1 Levels of PBDEs in the house dust . 138 8.3.2 Concentrations of organochlorines in house dust 143 8.3.3 House characteristics and the levels of POPs 150 8.3.4 Health risks of exposure to POPs in Singapore 152 8.4 CONCLUSIONS 155 CHAPTER CONCLUSION AND FUTURE EFFORTS . 156 9.1 CONCLUSIONS OF THE STUDY 156 9.2 SUGGESTIONS FOR FUTURE WORK . 159 REFERENCES 162 APPENDIX A. 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Level, sources and toxicity of polychlorinated biphenyls in the Italian diet. Chemosphere 38, 2753-2765. 206 Appendix A APPENDIX A. PCB NOMENCLATURE CONVERSION TABLE (ADAPTED FROM FRAME ET AL. (1996)). Chlorine None positions 2’3’4’5’6’ 2’3’5’6’ 2’3’4’6’ 2’3’4’5’ 3’4’5’ 2’4’6’ 2’4’5’ 2’3’6’ 2’3’5’ 2’3’4’ 3’5’ 3’4’ 2’6’ 2’5’ 2’4’ 2’3’ 4’ 3’ 2’ None 11 15 13 23 40 22 20 16 24 47 42 28 25 17 25 52 49 44 31 26 18 26 54 53 51 46 32 27 19 10 34 77 71 70 66 56 37 35 33 12 35 80 79 73 72 68 58 39 36 34 14 234 128 107 105 89 87 85 82 60 55 41 21 235 133 130 111 109 94 92 90 83 63 57 43 23 236 136 135 132 113 110 96 95 91 84 64 59 45 24 245 153 149 146 138 120 118 102 101 99 97 74 67 48 29 246 155 154 150 148 140 121 119 104 103 100 98 75 69 50 30 345 169 168 167 164 162 157 127 126 125 124 123 122 81 78 76 38 2345 194 189 182 180 174 172 170 159 156 143 141 137 129 114 106 86 61 2346 2356 23456 197 196 191 184 183 176 175 171 161 158 145 144 139 131 115 108 88 62 202 201 199 193 188 187 179 178 177 165 163 152 151 147 134 117 112 93 65 209 208 207 206 205 204 203 200 198 195 192 190 186 185 181 173 166 160 142 116 207 Appendix B APPENDIX B. GC-MS PARAMETERS IN SIM MODE. Mode EI a NCI Analyte Retention Quantification Confirmatory time (min) ion ion 7.3 to 10.8 217 219 trans-chlordane 21 373 375 cis- chlordane 21.8 373 375 p,p’-DDT 29 235 237 p,p’-DDD 26.6 235 237 p,p’-DDE 23.8 246 248 Tri-PCBs 9.6 to 13.6 256 258 tetra-PCBs 15.6 to 20 292 294 penta-PCBs 20 to 27.5 326 328 hexa-PCBs 24.8 to 34.6 360 362 hepta-PCBs 30 to 34.9 396 398 octa-PCBs 35 to 38.7 426 428 nona-PCBs 37.3 to 40 462 464 deca-PCB 41 496 498 9.5-18.6 79 81 18.5 487 489 HCHs PBDE except 209b PBDE 209c a : Obtained using GC program as described in Section 4, Chapter 3. b : Obtained using GC program as described in Section 4, Chapter 3. c : Obtained using GC program as described in Section 2.3, Chapter 8. 208 Publications PUBLICATIONS Journal Publications Tan J, Loganath A, Chong YS, Obbard JP. 2009. Exposure to Persistent Organic Pollutants in utero and Related Maternal Characteristics on Birth Outcomes: A Multivariate Data Analysis Approach. Chemosphere. 74: 428-433 Tan J, Li QQ, Loganath A, Chong YS, Xiao M, Obbard JP. 2008. Multivariate Data Analyses of Persistent Organic Pollutants in Maternal Adipose Tissue in Singapore. Environ Sci Technol 42: 2681-2687. Tan J, Loganath A, Chong YS, Obbard JP. 2008. Persistent persistent organic pollutants in human blood: A review of worldwide data and data for Singapore. Toxicological & Environmental Chemistry. 90: 837-859. Tan J, Cheng SM, Loganath A, Chong YS, Obbard JP. 2007. Polybrominated diphenyl ethers in house dust in Singapore. Chemosphere 66: 985-992. Tan J, Cheng SM, Loganath A, Chong YS, Obbard JP. 2007. Selected organochlorine pesticide and polychlorinated biphenyl residues in house dust in Singapore. Chemosphere 68: 1675-1682. Li QQ, Loganath A, Chong YS, Tan J, Obbard JP. 2006. Levels of persistent organic pollutant residues in human adipose and muscle tissues in Singapore. J Toxicol Environ Health A 69: 1927-1937. Li QQ, Loganath A, Chong YS, Tan J, Obbard JP. 2006. Persistent organic pollutants and adverse health effects in humans. J Toxicol Environ Health A 69: 1987-2005. Manuscripts - Provisionally Accepted/Submitted/Pending Tan J, Loganath A, Chong YS, Obbard JP. Persistent organic pollutants in human breast milk in Singapore: Influential factors and the health risks of infants. Journal of Toxicology and Environmental Health, Part A. Under review. Book chapters Obbard JP, Li QQ, Loganath A, Chong YS, Tan J, Bayen S. 2007. Chapter 16 Persistent Organic Pollutants and Adverse Health Effects in Humans in Singapore. In: Developments in Environmental Sciences: Elsevier, 721-752. Conference Publications/Presentations 209 Publications Tan J, Lin WX, Loganath A, Chong YS, Obbard JP. 2007. Persistent organic pollutants (POPs) in the inhabitants Singapore. Oral Presentation in Graduate Student Symposium in Department of Chemical and Biomolecular Engineering, NUS. Singapore. 210 [...]... there is still a lack of comprehensive understanding on the impact of human exposure to POPs in Singapore, particularly those pertaining to the health risks of fetuses and infants 1.2 Research Objectives Due to the paucity of data and knowledge gaps in Singapore, the aim of this research was to evaluate the human perinantal exposure to POPs, namely organochlorine pesticides (OCPs), polychlorinated biphenyls... (Brown et al., 1994; Hakk and Letcher, 2003) 2.3 2.3.1 Human Exposure to POPs Exposure pathways The exposure pathways to POPs for humans include food and water intake, dermal absorption, and inhalation of ambient air and airborne particles (Duarte-Davidson and Jones, 1994) Food consumption has been regarded as the most important route of exposure for the general population (Dougherty et al., 2000; Stefanelli... umbilical cord blood (Chapter 5); • To investigate the impact of POPs on fetal growth and development in the general population of Singapore by exploring the correlations between intrauterine exposure to POPs and the newborn birth outcome (Chapter 6); • To assess the potential risks of postnatal exposure to POPs on infants’ health via breastfeeding, and to explore the factors regulating the elimination... 1991) γ-HCH, commonly referred to as Lindane, is used extensively for agricultural and public health purposes worldwide In organisms, the gamma isomer is biotransformed to conjugated chlorophenols and excreted rapidly from the body In contrast, β-HCH is metabolized very slowly and has a stronger tendency to become incorporated into food chains Therefore, beta isomer was found to be the most prevalent in... man-made chemicals have made to modern civilization, they are now known to have many undesirable adverse effects on the environment and human health POPs are highly resistant to degradative processes 1 Chapter 1: Introduction and Objectives and can readily bioaccumulate and biomagnify through the food chain to eventually reach peak levels in top predator species (Harrad, 2001) Humans are typically at the... POPs in human body Alimentary habit is ascertained to be one of the important indicators Age has also emerged as a predictor for the levels of pesticide and PCBs in human tissue, where an age-dependent accumulation of POPs has been observed in many studies (Kutz et al., 1991a) No such trend was observed for PBDEs, which is probably due to the relatively shorter half-lives of these compounds in the human. .. required, including analytical chemistry, physiology, toxicology, and statistical analysis Therefore, the following chapter reviews the available literature on the physico-chemical characteristics of POPs, their environmental behavior, the up -to- date findings on human exposure, the adverse effects of POPs on human health, and the analytical methods for POP detection in various matrices 6 Chapter 2: Literature... compounds, two kinds of by-products are formed, i.e polychlorinated dibenzo-p-dioxins (PCDDs) and -furans (PCDFs) which were later found to induce extreme toxicity to the environment and humans Recently, man-made brominated compounds, specifically, the brominated flame retardants (BFRs) have become a matter of escalating concern, due to their toxic effects on both wildlife and humans (Darnerud et al., 2001;... a database on human perinatal exposure of POPs in Singapore, and illustrated the transfer behavior of POPs between mother and fetus The study has advanced our scientific understanding on the vertical transmission of POPs between mother and fetus, and highlighted the need for further ix Summary epidemiological studies to further elucidate the relationship between POP exposure and human health x List... Therefore, the last objective of this study was: • To determine the prevailing levels of POPs in house dust, and to assess the health risks to children and adults in Singapore via ingestion and inhalation of contaminated house dust Finally, an overall health risk assessment was performed based on the available data considering all potential human exposure pathways (Chapter 8) 5 Chapter 1: Introduction . PERINATAL EXPOSURE TO PERSISTENT ORGANIC POLLUTANTS: IMPLICATIONS FOR HUMAN HEALTH TAN JING NATIONAL UNIVERSITY OF SINGAPORE 2008 PERINATAL EXPOSURE TO PERSISTENT. INTRODUCTION TO POPS 7 2.2 ENVIRONMENTAL BEHAVIOR OF POPS 12 2.3 HUMAN EXPOSURE TO POPS 14 2.3.1 Exposure pathways 14 2.3.2 Prevalence of POPs in humans 15 2.3.3 Perinatal exposure to POPs 17. EXPOSURE TO PERSISTENT ORGANIC POLLUTANTS: IMPLICATIONS FOR HUMAN HEALTH TAN JING (B.Eng., Wuhan University, China) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT