Steven R. Corsi Michelle A. Lutz Christopher G. Ingersoll Rebecca A. Dorman Christopher Magruder Matthew Magruder Austin K. Baldwin 2017 <p><span>High concentrations of polycyclic aromatic hydrocarbons (PAHs) in streams can be a significant stressor to aquatic organisms. To understand the likely sources and toxicity of PAHs in Milwaukee-area streams, streambed sediment samples from 40 sites and parking lot dust samples from 6 sites were analyzed for 38 parent PAHs and 25 alkylated PAHs. Diagnostic ratios, profile correlations, principal components analysis, source-receptor modeling, and mass fractions analysis were used to identify potential PAH sources to streambed sediment samples, and land-use analysis was used to relate streambed sediment PAH concentrations to different urban-related land uses. On the basis of this multiple lines-of-evidence approach, coal-tar pavement sealant was indicated as the primary source of PAHs in a majority of streambed sediment samples, contributing an estimated 77% of total PAHs to samples, on average. Comparison to the Probable Effect Concentrations and (or) the Equilibrium Partitioning Sediment Benchmark indicates that 78% of stream sediment samples are likely to cause adverse effects to benthic organisms. Laboratory toxicity tests on a 16-sample subset of the streambed sites using the amphipod </span><i>Hyalella azteca</i><span> (28-day) and the midge </span><i>Chironomus dilutus</i><span> (10-day) measured significant reductions in one or more biological endpoints, including survival, in 75% of samples, with </span><i>H. azteca</i><span> more responsive than </span><i>C. dilutus</i><span>.</span></p> application/pdf 10.1002/etc.3694 en Society of Environmental Toxicology and Chemistry Primary sources and toxicity of PAHs in Milwaukee-area streambed sediment article