POTENTIAL FOR HUMAN EXPOSURE TO TOXAPHENE THROUGH CONSUMPTION OF GREAT LAKES FISH Prepared for the Great Lakes Consortium by the Wisconsin Department of Health Services

Concerns have been raised about the presence of the bioaccumulating pesticide toxaphene in the tissues of Great Lakes fish. Toxaphene, banned in the U.S. since 1990, is an environmentally persistent chlorinated hydrocarbon mixture of over 670 chemical congeners. Current fish consumption advisories issued in the Great Lakes states focus on concentrations of PCBs and mercury in fish. The Great Lakes Consortium is now considering whether toxaphene should also influence fish consumption advisories. In this report, an exposure assessment was conducted using toxaphene concentrations in Great Lakes fish tissue collected and analyzed from 2010-2012 by the Departments of Natural Resources of Michigan, Minnesota, and Wisconsin. The exposure assessment addressed several consumption frequencies used to issue consumption advice (unrestricted, 1 meal/week, 1 meal/month, 6 meals/year, and no consumption). Scenarios assumed a 70 kg adult and proper fish cleaning and cooking techniques. Due to the absence of an EPA-issued reference dose (RfD) for toxaphene, toxicology studies were reviewed and used to calculate a comparable value of 1.11 × 10-4 mg/kg-day. Highest toxaphene exposures resulted from consumption of siscowett lake trout from Lake Superior, which should be restricted to 1 meal/week. No other type of fish from either Lake Superior or Lake Michigan required toxaphene-driven restrictions. It was concluded that fish consumption advisories currently in place to address exposures to mercury and PCBs would also be protective of toxaphene exposures. Therefore, no revisions to current consumption advisories are recommended.