| Temporal Trends of Organochlorine Concentrations in Umbilical Cord Blood of Newborns from the Lower North Shore of the St. Lawrence River (Québec, Canada) Frédéric Dallaire, Éric Dewailly, Claire Laliberté, Gina Muckle, and Pierre Ayotte Public Health Research Unit, Laval University Medical Center, and Laval University, Québec, Canada Abstract
This study describes the time trends of organochlorines [OCs ; 14 polychlorinated biphenyls (PCBs) and 11 chlorinated pesticides] in umbilical cord plasma of newborns in a remote Canadian coastal population. We analyzed 408 cord blood samples collected between 1993 and 2000 for PCBs, chlordanes, dichlorodiphenyltrichloroethane (DDT) , dichlorodiphenyltrichloroethylene (DDE) , hexachlorobenzene (HCB) , and n-3 fatty acids. We also gathered information on the mothers (age, past and present residence, ethnic group, use of tobacco during pregnancy, and breast-feeding during previous pregnancies) . From 1993 to 2000, mean concentrations of PCBs, chlordanes, DDT/DDE, and HCB in cord blood decreased by 63%, 25%, 66%, and 69%, respectively (p < 0.0001) . Multiple regression analysis with the year of birth as the main independent variable yielded a strong significant exponential decrease for all contaminants (in all age and ethnic groups) . We detected no monthly or seasonal pattern. We used n-3 fatty acids concentration as a surrogate of maternal fish consumption. Fish consumption declined only slightly between 1993 and 2000, but this decrease did not contribute significantly to the reduction of OCs. These results show that prenatal exposure to persistent OCs has declined significantly between 1993 and 2000 in this population. Key words: aboriginal, chlorinated pesticides, coastal population, diet, environmental exposure, food contamination, human, newborn, polychlorinated biphenyls, pregnancy, seafood, time trend, umbilical cord blood. Environ Health Perspect 110:835-838 (2002) . [Online 9 July 2002] http://ehpnet1.niehs.nih.gov/docs/2002/110p835-838dallaire/ abstract.html Address correspondence to É. Dewailly, Public Health Research Unit, 2400 rue d'Estimauville, Beauport, Québec, Canada G1E 7G9. Telephone: (418) 666-7000. Fax: (418) 666-2776. E-mail: eric.dewailly@crchul.ulaval.ca We are indebted to G. Lebel for database management, to J.-P. Weber and É. Pelletier (Québec Toxicology Center) for OC analyses, to B. Holub for lipid analyses, and to the staff of Sept-Iles Hospital and Blanc Sablon Hospital for their useful assistance. We thank the Saint-Laurent Vision 2000 program for financial support. F.D. is supported by the Canadian Institutes of Health Research. Received 11 January 2002 ; accepted 8 February 2002.
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