History of Inuit community excretion of polychlorinated biphenyls recorded in sewage lake sediments

Abstract

Exposure to polychlorinated biphenyls (PCBs) is high among the Inuit resulting from ingestion of contaminated wild "country" foods. These contaminants originate in urban/industrial areas and reach the Arctic by long-range atmospheric transport. Ingested PCBs eventually equilibrate into various body components, including feces, which become an indication of body burden. Bulk domestic sewage residue from a community will accumulate PCBs from feces; long-term accumulated sediments from a sewage treatment system are a historical indicator of changes in community-wide PCB excretion. In this study, sediment cores were collected from the domestic sewage treatment lake, known as Annak, for the Inuit Hamlet of Sanikiluaq, Canada (established 1967), and were dated (Pb-210, Cs-137) and analyzed for 127 PCB congeners. We focused our attention on the 47 congeners that were observed consistently. Atmospheric and local inputs to a nearby lake accounted for local background. PCB inputs from sewage grew rapidly from the late 1960s until 1990. The maximum 47 congener SigmaPCB excretion occurred in approximately 1989 (11116 ng person(-1)d(-1)); all sewage PCB inputs were dominated by PCB 153, PCB 138 and PCB 180. PCB ingestion from a Sanikiluaq food survey in 1989 for 11 of the most highly concentrated PCB congeners (7270 ng person(-1)d(-1)) was the same as our excretion estimate for the same congeners (7348 ng person(-1)d(-1)) that year, suggesting that by the late 1980s, the ingested amount of PCB was similar to what was excreted every day, although the latter is a reflection of body burden and not short-term exposure.