What are EcoTox Thresholds?
A. The Superfund program has initiated a project to develop media-specific benchmark values for those chemicals commonly found in surface water, sediment and soil samples at sites (values for soil are still being developed). The values are referred to as Ecotox Thresholds (ETs), and are defined as media-specific contaminant concentrations above which there is sufficient concern regarding adverse ecological effects to warrant further site investigation. ETs are designed to provide Superfund site managers with a tool to efficiently identify contaminants that may pose a threat to ecological receptors and focus further site activities on those contaminants and the media in which they are found. ETs are meant to be used for screening purposes only; they are not regulatory criteria, site-specific cleanup standards, or remediation goals. For those chemicals with the potential to bioaccumulate to toxic levels in upper trophic wildlife (e.g., methyl mercury, PCBs, DDT, dioxins, and lead), these
