Stuck in the Mud: Multiple Causes of Ecological Risk in Sediment

Assessment of potential ecological risk to benthic organisms inhabiting these sediments is often necessary to determine risk-based remedial cleanup goals. In some cases, these ecological risk assessments (ERAs) can be relatively straightforward, focusing only on the visual presence of tar or sheen in sediment cores or on PAH concentrations linked to unacceptable risk thresholds. However, ERAs can also be complicated by the presence of other contaminants, and/or the presence of multiple physical stressors not related to former MGP operations. These complications can arise for several reasons: • The site is located near an urban waterway with many other active or historical industries and their impacts, including metals, pesticides, or PCBs.