What is Ecological Risk Assessment?
Risk Assessment in Superfund
An important part of an investigation of a Superfund site is the Remedial
(cleanup) Investigation and Feasibility Study (RI/FS). The RI/FS process
is designed to help determine what, if any, action should be taken at a Superfund
site. The purpose of the Remedial Investigation (RI) portion is to determine
what contaminants are associated with the site and how large an area is contaminated.
An important part of the RI is the risk assessment. All Superfund site risk
assessments should be comprised of two parts, a human health risk assessment
and an ecological risk assessment. The purpose of the Feasibility Study (FS)
is to evaluate the choices of a remedy to address site-related risks. Only
wildlife is considered in an Ecological Risk Assessment (ERA); domesticated
animals or domesticated plants are excluded from the ERA. The process for
performing an ERA is described in detail in the Ecological
Risk Assessment Guidance for Superfund, Process for Designing and Conducting
Ecological Risk Assessments (EPA 540-R-97-006). The main steps of an ERA
are outlined in the Eight-step Overview found
on this website.
Definition of Ecological Risk Assessment (ERA)
Ecological Risk Assessment is defined as "A process that evaluates the likelihood that adverse ecological effects are occurring or may occur as a result of exposure to one or more stressors" (U.S. EPA 1992b). As used in Superfund, the phrase "ecological risk assessment" means an investigation into the actual or potential impacts of contaminants from a hazardous waste site on plants and animals other than humans or domesticated species. A risk does not exist unless: (1) the contaminant has the ability to cause an adverse effect and (2) a plant or animal can come in contact with a contaminant long enough and at a high enough concentration that the contaminant causes an adverse effect.
Goals of the Ecological Risk Assessment (ERA)
There are four main goals of an ecological risk assessment (ERA):
- To determine whether harmful effects are likely for wild animals or plants exposed to site related hazardous chemicals; these harmful effects are referred to as a significant risk;
- If there is significant risk, to calculate a protective cleanup level that would reduce the risk to wild animals or plants;
- To determine the potential impact of cleanup activities on the habitats, plants, or animals; and
- To provide information that can be used as a baseline for long-term biological monitoring programs to determine if the cleanup is effective.