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Levels of Mercury in Fish from the Northeast US
Citation:
Melnyk, L., J. Lin, J. Lazorchak, D. Kusnierz, K. Pugh, AND M. Stover. Levels of Mercury in Fish from the Northeast US. ISES ISIAQ 2019 Joint Annual Meeting, Kaunas, LITHUANIA, August 18 - 22, 2019.
Impact/Purpose:
The research conducted for this study highlights the contamination of mercury in fish that are potentially consumed by humans and wildlife. The daily consumption rates were calculated to ensure a safe level for both humans and wildlife. Current health advisories are sufficient to protect humans, except for sea lamprey which contained the most mercury of all species tested. This information is valuable to communities who rely on subsistence fishing and to those wanting to protect wildlife.
Description:
Rivers in the Northeast are home to spawning anadromous and non-migratory fish that are caught and consumed by subsistence fisherman. Fish have been barred from entering some rivers by dams constructed during an industrial boon that occurred over 100 years ago. With dam removal as an effort to restore ecological health of the river system, anadromous fish are again entering rivers and are available for consumption. The safety of human and wildlife consumers is paramount, so the levels of mercury were measured in tissue of six species of migratory fish (Alewife, American Shad, Blueback Herring, Rainbow Smelt, Striped Bass, and Sea Lamprey), as well as, in the roe of one species (American Shad) for two consecutive years (2017 and 2018). The resultant mercury levels were compared to reference doses as established in the US Integrated Risk Information System and wildlife values. Mercury concentrations ranged from around 10 µg/kg in roe samples to around 650 µg/kg in Sea Lamprey. An average person of body weight 70 kg could safely consume between 0.4 and 6 oz (11 and 170 g) of fish fillet daily, depending on species. The roe contained the least amount of mercury, and therefore, could be safely consumed at levels over 20 oz per day. Sea lamprey contained the highest amounts of mercury for both seasons of sampling. Current health advisories near the study are set at sufficient levels to protect fishermen from harmful consumption of the fish species, except for sea lamprey. Based upon a consumption wildlife value of 70 mg/kg for Mink and 100 mg/kg for Otter, consumption of Alewife, Striped Bass and Sea Lamprey pose a risk to Mink. Consumption of Rainbow Smelt, Striped Bass and Sea Lamprey pose a risk to Otters. It was determined that Sea Lamprey, with consistently higher concentrations of mercury than the other species analyzed, pose a health risk if consumed at levels greater than 0.5 oz/d (14 g/d).
