Are Lake Trout (Salvelinus namaycush) From Flathead Lake, Montana, USA “Safe” To Eat? An Integrated Mercury Risk Evaluation Study∗

∗Presented in part at Pacific Northwest Chapter of the Society of Environmental Toxicology and Chemistry (PNW-SETAC), 18th Annual Meeting, Port Townsend, WA, April 16–18, 2009

Abstract

This study focused on evaluating the appropriateness of the State of Montana consumption guidelines for Lake Trout (Salvelinus namaycush) from Flathead Lake, Montana, USA. This lake is jointly managed by the State and the Confederated Salish and Kootenai Tribes. Thousands of lake trout are harvested by the Tribes and donated to local food banks yearly. Samples from forty-eight lake trout were analyzed for mercury, selenium and polyunsaturated fatty acids (PUFAs). Models that seek to quantify the moderating or attenuating effects of both selenium and omega-3 (n-3) PUFAs on mercury toxicity were integrated with the US Environmental Protection Agency (EPA) methods for setting consumption guidelines in an attempt to better determine “safe” consumption recommendations. Omega-3 PUFAs benefits (neurodevelopmental and cardiovascular) were balanced with mercury detriment to yield a potential net health risk/benefit. Consumption of lake trout, of any size, failed to show any predicted neurodevelopmental benefits. However, small cardiovascular benefits were predicted for shorter fish. Selenium levels were not limiting. Data from this study indicates the State consumption guidelines may not be adequately protective for the general public, and new guidelines have been proposed. Separate, more conservative guidelines may be considered for the food bank users pending the outcome of an upcoming study.

Keywords:

• mercury
• lake trout
• risk
• selenium
• fatty acids

Acknowledgements

This work was funded by National Institutes of Health award # R25-GM076323 (National Institute of General Medical Sciences Research Initiative for Scientific Enhancement Program). Fish were provided by the Tribal Fisheries Program, Confederated Salish and Kootenai Tribes. Statistics consultation was provided by the Center for Biomedical Statistics, University of Washington.

Notes

∗Presented in part at Pacific Northwest Chapter of the Society of Environmental Toxicology and Chemistry (PNW-SETAC), 18th Annual Meeting, Port Townsend, WA, April 16–18, 2009