An approach for estimating ecological risks from organochlorine pesticides to terrestrial organisms at rocky mountain arsenal

Abstract

Ecological risk assessment for bioaccumulative chemicals at hazardous waste sites like Rocky Mountain Arsenal (RMA) is challenging, particularly when the site is large and is characterized by heterogeneous environments and patterns of contamination. Because RMA is an National Priorities List site and a future wildlife refuge, an effective and practical risk assessment approach was required. This approach includes methods to estimate contaminant concentrations below detection limits, spatial and temporal integration, bioaccumulation, and toxicity criteria. Validation of the quantitative risk assessment approach was achieved through comparisons of observed versus predicted tissue concentration values, as well as evaluation of ecological endpoints relative to wildlife health. The results of the assessment based on this approach provide a realistic representation of observed conditions at RMA, and provide quantitative conclusions that are consistent with qualitative observations of the health and diversity of biota at RMA. In addition to supporting baseline risk assessment, the approach provides a useful framework for evaluation of future risk management alternatives.

Key Words:

• ecological risk assessment
• bioaccumulation factor
• dose‐based food‐web model
• dieldrin
• Rocky Mountain Arsenal

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