Background/Question/Methods   The Duwamish River is an industrial waterway and EPA Superfund site in Seattle, WA where we determined concentrations of contaminants across multiple sites within the estuarine lower river to examine impacts on benthic invertebrates. Our past work assessed how restoration efforts affected water quality (DO, pH, temperature, salinity, etc.) and community measures (plankton abundance and diversity). We built on that work through routine monitoring of isopod, amphipod, and polychaete populations to establish how densities and individual sizes varied across sites. To investigate relationships among invertebrates, aquatic environmental conditions, and contaminant concentrations, we measured pyrethroid pesticides across the same set of sites over time.

Results/Conclusions   Preliminary results suggest we are capable of detecting pyrethroid presence within the sites studied, and could explore relationships with invertebrate densities, sizes, and behaviors. In particular, through experiments focused on individual isopod feeding and growth rates, we quantified how stress reduced isopod consumption of detritus. We found differences in contaminant concentrations among study sites, with potential sources from Combined Sewer Overflow inputs contributing. This project will further examine how contaminants vary across sites and over time, with additional chemicals to be explored, and specific impacts on benthic invertebrate densities, sizes, and relevant behaviors with consequences for other food web components.