USEPA REGION 4
- Avatar designed a field sampling and ecological risk assessment approach.
- Potential Ecological Data Gaps Technical Memorandum
- Narcosis Approach to assessing potential ecological risks to benthic communities
- Baseline Ecological Risk Assessment (BERA)
- Field Sampling and Sediment Toxicity Testing
Avatar designed a field sampling and ecological risk assessment approach for this former creosote manufacturing plant. The Baseline Ecological Risk Assessment (BERA) documented the potential exposure and consequent risk to ecological receptors using the Holcomb Creosote Site. The site was divided into four ecological exposure areas: Facility Area; Landfarm; Unnamed Tributary and associated wetlands; and Dobbins Pond.
The technical approach was negotiated with and agreed to by EPA Region 4, after the development of Potential Ecological Data Gaps Technical Memorandum. One aspect of which was that Avatar convinced EPA to use the narcosis approach to assessing potential ecological risks to benthic communities in the large wetland complex and recreational lake, thereby reducing the need for widespread sediment sampling.
In addition to traditional surface soil, sediment and surface water chemistry collection, biological tissue (whole body fish) was collected from Dobbins Pond and submitted for chemical analysis, and sediment toxicity tests were conducted for the Unnamed tributary and Wetlands Complex, and Dobbins Pond. These additional analyses provided extra lines of evidence for the associated exposure areas and helped to substantially reduce the uncertainty of any estimated ecological risk.