Risk Assessment for Fish, Invertebrates, and Unionids, Walnut Creek Indiana, Superfund Site

May 2005 – August 2006

  • Determine fish, invertebrate, and unionid community composition

  • Fish, Aquatic Macroinvertebrate Sampling

  • Tote-barge Electrofishing, EPA RBP Macroinvertebrate Collection Methods

  • Abundance, Trophic Classification, Species Richness, Fish Length and Weight

  • Fish Tissue Collection for Toxicity Testing

  • Ecological Risk Assessment

EcoAnalysts was contracted by Symbiont to assist in a risk assessment for the City of Warsaw, at the Walnut Creek Superfund site. EcoAnalysts’ primary responsibilities were to collect biological data, determine if biological communities differed from uncontaminated (reference) sites based on community indices (IBI, mIBI) and principal component analysis (PCA), assess risks to the biological community from site contamination (based on sediment and water quality samples), and prepare technical documentation for insertion into the final Risk Assessment report prepared by Symbiont.


Reference sites and impact sites were selected within the Walnut Creek and Tippecanoe River watersheds for habitat, fish, and macroinvertebrate collection to determine biological integrity at those sites. Tote barge electrofishing was used to collect fish. Fish were identified and tissues were collected from representative species. The EPA RBP methods were used to collect benthic macroinvertebrate samples. All samples were processed in the EcoAnalysts laboratory and taxa were identified to the lowest level possible. Habitat evaluation (HSI) was also performed at each site.

The client prepared a technical document; however, Ecoanalysts contributed sections on fish, mussel, invertebrate, and habitat conditions within the contaminated and reference sites. Contaminant levels were evaluated with respect to water and sediment quality standards for aquatic life.

Scott Mackey