PCBs and dioxin-like compounds in plasma of adult inuit living in Nunavik (Arctic Quebec)

Inuit people residing in the Arctic are unusually exposed to organochlorines through their traditional diet which includes large quantities of sea mammal fat. Recently, 499 Inuit adults from Nunavik (Arctic Quebec) participated in a large health survey and donated a blood sample for organochlorine and heavy metal analysis. Twenty pooled plasma samples were formed, each made of individual samples from the same age group, sex, and region of residence, to allow for dioxin-like compound determination. The mean total concentration of PCBs and dioxin-like compounds (the latter expressed in 2,3,7,8-TCDD toxic equivalents) were respectively 4.1 mg/kg lipids and 184.2 ng/kg lipids, compared to 0.13 mg/kg and 26.1 ng/kg lipids for three control pooled plasma samples from Southern Quebec. Total PCBs and dioxin-like compound concentrations were strongly correlated (r = 0.98; p < 0.0001), increased with age and were greater in men than in women. Although the body burdens of PCBs and dioxin-like compounds are close to those which induced adverse health effects in laboratory animals, dietary benefits from the sea-food based diet still outweigh the hypothetical health risks.