Subsistence fish consumption in rural Alaska: Using regional monitoring data to evaluate risk and bioavailability of dietary methylmercury

Abstract

On average, Alaskans in rural communities consume over three times the Federally recommended maximum weekly fish ingestion rate (IR), the overwhelming majority of which is Pacific salmon. Results of statewide monitoring efforts consistently show that Pacific salmon from Alaska have low concentrations of mercury, yet concerns regarding dietary exposure to methylmercury (MeHg) and other aquatic contaminants continue to contribute to declining subsistence fish consumption rates in rural communities. Therefore, the goal of the present study was to use statewide biomonitoring datasets and regional fish IRs to quantitatively evaluate potential risk from dietary MeHg exposure via subsistence consumption of salmon from Alaska. Hazard Indices (HIs) did not exceed 1 for any of the groups evaluated, indicating negligible risk for the average Alaskan subsistence consumer. Selenium health benefit values (HBV_Se) of various fish species from AK were also calculated, with positive results for all commonly consumed subsistence species. Additionally, mercury concentrations in the hair of Alaskan women were evaluated as a proxy for dietary MeHg exposure. Results reveal that Alaskan women of childbearing age have substantially lower hair Hg concentrations than their counterparts in other large-scale biomonitoring studies, despite similar fish IRs. Collectively, results of the present study suggest that MeHg in Pacific salmon does not pose an unacceptable hazard for the average subsistence consumer in Alaska.

Keywords: Alaska; Biomonitoring; Fish consumption; Mercury; Selenium health benefit; Subsistence.