Model Estimates Bioaccumulation of Total PCBs, Dioxin-Furan TEQs, and Total Mercury in Mink Liver Based on Concentrations in Lake Ontario Water

We used stable isotope analysis and a bioaccumulation model to estimate concentrations of total polychlorinated biphenyls (PCBs), dioxin-furan toxic equivalents (TEQs), and total mercury (Hg) in mink and to compare predicted ranges with their chemical concentrations in mink liver (PCB, TEQ) and brain (Hg). Actual concentrations were within predicted bounds for total PCB, dioxin-furan TEQ, and Hg except in two cases (lowest PCB and highest Hg) which were very close to predicted bounds. Based on ¹⁵N analysis, the trophic level of mink ranged from 3.4 to 3.9. Animals at the upper end of the range were exposed to Lake Ontario water and its food web, whereas those at the lower end were captured at inland locations. Because of the complexity of wetland (an important habitat for mink in this study) food webs with pelagic, littoral, and terrestrial carbon sources and overlapping ¹³C signatures, whether the origins of mink diets were aquatic or terrestrial could not be determined. We have established a nondestructive biomonitoring tool to reasonably estimate concentrations of total PCBs, TEQs and total Hg in mink tissues as concentrations of these chemicals change in their water supply.