Organochlorine levels in maternal and umbilical cord blood plasma in Arctic Canada

Abstract

A baseline for exposure to organochlorine and metal contaminants has been established for mothers and newborns in the Northwest Territories and Nunavut areas of Arctic Canada. Maternal and umbilical cord blood plasma organochlorine levels are described for Inuit, Dene, Métis, Caucasian and Other non-Aboriginal participants. Overall, 523 women volunteered to participate by giving their written informed consent between May 1994 and June 1999, resulting in the collection of 386 maternal blood samples, 407 cord blood samples and 351 maternal/cord pairs. Nearly half of all the participants regularly smoked cigarettes, including 77% of the Inuit participants. Maternal and cord results are presented for PCBs (as Aroclor 1260 and 14 congeners) and organochlorine pesticides, including p, p′-DDT, p, p′-DDE, beta-hexachlorocyclohexane (β-HCH), hexachlorobenzene (HCB), cis and trans nonachlor, heptachlor epoxide, oxychlordane, mirex, dieldrin and toxaphene. Maternal PCB levels (as Aroclor 1260) averaged 4.42 (±9.03) μg/l in Inuit, which was 3.3 times higher than those found in Dene/Métis, and 3.4 times higher than levels in Caucasians. Mean DDE levels were 2.8 times higher in the Other non-Aboriginal group (Chinese, Filipino, East Indian and multiple ethnicity) than in the Inuit group, at 3.99 μg/l and 1.42 μg/l, respectively. Cord blood PCB levels (as Aroclor 1260) averaged 1.16 (±2.42) μg/l for Inuit participants, which was 3.3–4 fold higher than the other ethnic groups. PCBs, p, p′-DDE and hexachlorobenzene were detected in all maternal samples, and p, p′-DDE was detected in all cord samples. Regression coefficients for maternal/cord pairs are presented for selected organochlorines. Other results from this study, including maternal and cord metals data, will be presented elsewhere.