SEDIMENT-TOXICITY ASSESSMENT AND CONTAMINANT-SOURCE TRACKING AT TWO WISCONSIN AREAS OF CONCERN (AOCS) AND NON-AOC COMPARISON TRIBUTARIES TO LAKE MICHIGAN
Great Lakes Areas of Concern (AOCs) are some of the most degraded areas within the Great Lakes basin. Two Lake Michigan AOCs, the Sheboygan River and Milwaukee Estuary, were listed, in part, because of sediment contaminated by polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and metals. In fall 2016, the U.S. Geological Survey collected composite samples of streambed sediment from 19 sites— 11 at the Sheboygan River and Milwaukee Estuary AOCs and 8 at non-AOC comparison sites. Sediment was analyzed for concentrations of PCBs, PAHs, and selected metals, along with midge and amphipod toxicity. Amphipod toxicity at the sites was found to be primarily related to PAHs and secondarily to metal concentrations in the sediment. Source tracking techniques, such as the comparison of PAH diagnostic ratios and proportional concentrations of PAH congeners in each sediment sample to published PAH sources, were used to estimate the most likely sources of PAHs to sediment at each AOC and non-AOC comparison site. The results from this study will be used to evaluate remediation progress and determine future remedial actions for improving contamination and toxicity to benthic invertebrates at these sites.
Hayley Olds (Primary Presenter/Author), U.S. Geological Survey, email@example.com;
Barbara Scudder Eikenberry (Co-Presenter/Co-Author), U.S. Geological Survey, firstname.lastname@example.org;
John Besser (Co-Presenter/Co-Author), U.S. Geological Survey, email@example.com;
Rebecca Dorman (Co-Presenter/Co-Author), U.S. Geological Survey, firstname.lastname@example.org ;