WP14 Uncertainty Analysis in Risk Assessment: Influences on Decision-making
Wednesday, 16 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(MAH-1117-816607) Ecological Risk Assessment and its Application in Remediation Analysis.

Mahato, M, Roy, M,

ABSTRACT- Ecological Risk Assessment (ERA) is a tool that is limited by the certainty in the ecological data, but is becoming increasing an important factor in a site′s remedy/decision making process. Due to the complexity of ecological systems and their interactions with the multiple stressors, the antagonistic and synergetic effects of stressors are still unknown and in many ways ecological risk assessment is in a primitive stage and the uncertainty is addressed by using conservative assumptions. Use of a backcalculation of the Hazard Quotients (HQ) equation to determine a clean up goal may lead to a value potentially not reasonable or achievable. For example, a clean up value could be much lower than the background value. Prior to back calculating a clean up value, a weight of evidence analysis on the HQ value should be conducted such as an evaluation uncertainty factors or other exposure assumptions. Application of the same analytical tool to every problem will not lead to ′smart′ solution for potential risk at a site. The ERA process should be considered as part of the investigation process in determining site impacts, and all site specific factors should be evaluated in determining site clean-up goals. It is important to identify ecological stakeholders and have the goals of the ERA program defined early in the planning process and refined through the process. There should be an understanding of the ecological services for the site, and an appreciation for any potential enhancement of services. Stakeholders should understand the actual risk calculations, assumptions used in the process, as well as cost of the investigation and potential clean up options. The application of the risk values can be tempered with an understanding of the site, site services, environmental toxicity, fate of contaminants in the environment as well as understanding how the human health assessment fits into the site.

Key words: ERA, Application, Remediation, Analysis