This ECO Update builds on the standard approach to ERA (U.S. EPA 1997), by providing a framework for incorporating groundwater/surface-water (GW/SW) interactions into existing ERAs (see U.S. EPA 1997 and 2001a for an introduction to ecological risk assessment). The purpose of the ERA within the risk assessment process is to:

1. Identify and characterize the current and potential threats to the environment from a hazardous substance release;
2. Evaluate the ecological impacts of alternative remediation strategies; and
3. Establish cleanup levels in the selected remedy that will protect those natural resources at risk (U.S. EPA 1994a).

• ECO Update / Groundwater Foum Issue Paper: Evaluating Ground-Water/Surface-Water Transition Zones in Ecological Risk Assessments (PDF)(30 pp, 1 MB, 2008, 540-R-06-072)