Polychlorinated Biphenyl Concentrations in Fish from Lake Michigan Tributaries and a Preliminary Risk Assessment Concerning their Consumption by Sport and Tribal Fishermen

Human and environmental health continues to be threatened by persistent organic pollutants in the Great Lakes ecosystem. Polycholorinated biphenyls (PCBs) are considered one of the most toxic contaminants in the Great Lakes due to their recalcitrance, bioaccumulation, lipid solubility, and adverse health effects. The three main questions examined in this research were: 1) Do PCB concentrations vary between largemouth bass (Micropterus salmoides), northern pike (Esox Lucius), smallmouth bass (Micropterus dolomieu), and walleye (Sander vitreus) in west Michigan tributaries of Lake Michigan; 2) Do PCB concentrations vary on a watershed level among Manistee Lake, Muskegon Lake, Pentwater Lake, Tippy Pond, and White Lake; and 3) What are the risk levels associated with fish consumption by members of Little River Band of Ottawa Indians (LRBOI) and sport fishermen for the watersheds and fish species examined? Fish samples from Manistee Lake and Tippy Pond were caught via hook and line by members of LRBOI during 2004-2006 and 2008-2009. Fish samples from Muskegon, Pentwater, and White lakes were taken via boat electrofishing by the Michigan Department of Environmental Quality and the Annis Water Resources Institute during 2003-2006 and 2008-2009. The basins were chosen for their extensive use for recreational and tribal fishing. Fish were fileted, homogenized in a grinder and lipids from 20-g samples were extracted. Negative chemical ionization gas chromatography/mass spectrometry, gas chromatography with an electronic capture detector, and gas chromatography/high resolution mass spectrometry were used to measure PCB congener concentrations the fish tissue samples. Because of the variable methods in PCB congener measurements, PCB congeners were cross referenced and only the congeners that were found across all three methods were used in the statistical portions of the study. For the exposure and risk assessments, only those congeners that were measured and found in Aroclor 1254 were used for total PCB exposure calculations. The results showed that walleye were significantly higher in PCB content than largemouth bass, northern pike and smallmouth bass (p \u3c 0.05). Walleye were significantly higher in lipid content (p \u3c 0.05), which was linked to the high PCB content. Fish from Manistee Lake were significantly higher than Muskegon Lake, Pentwater Lake, Tippy Pond, and White Lake (p \u3c 0.05). In addition, exposures of sport anglers exceeded the reference dose of Aroclor 1254 in Manistee Lake with walleye from Manistee and White Lakes more than 10x the reference dose. Exposures of tribal members (LRBOI) exceeded 10x the reference dose in all species from Manistee Lake and walleye from Muskegon and White Lake. The risk assessment results suggest that basin specific consumption advisories should be considered for high risk groups