US EPA

The Proposed Guidelines for Ecological Risk Assessment were published in the Federal Register on September 9, 1996 (61 FR 47552) for a 90 day public review and comment period. The Proposed Guidelines are being developed to improve the quality of and consistency among EPA's ecological risk assessments. As a next step in a continuing process of ecological risk guidance development, the Proposed Guidelines expand upon the widely-used EPA report Framework for Ecological Risk Assessment, and EPA intends to prepare more detailed guidance in specific areas in the future. Risk assessors and risk managers at EPA are the primary audience for this document, although others outside the Agency (e.g., Agency contractors, state agencies, and other interested parties) may find the Proposed Guidelines to be useful.

Note: following review by EPA's Science Advisory Board and the public, this document was revised to become final Guidelines for Ecological Risk Assessment in 1998.

Ecological risk assessment is a process for organizing and analyzing data, information, assumptions, and uncertainties to evaluate the likelihood that one or more stressors are causing or will cause adverse ecological effects. Ecological risk assessment provides risk managers with a tool for considering available scientific information when selecting a course of action, in addition to other factors that may affect their decision (e.g., social, legal, political, or economic).

Ecological risk assessment includes three phases (problem formulation, analysis, and risk characterization). Within problem formulation, important areas include identifying goals and assessment endpoints, preparing a conceptual model, and developing an analysis plan. The analysis phase involves evaluating exposure to stressors and the relationship between stressor levels and ecological effects. In risk characterization, key elements are estimating risk through integration of exposure and stressor-response profiles, describing risk by discussing lines of evidence and determining ecological adversity, and preparing a report.

A major theme of the Proposed Guidelines is the interactions between risk assessors and risk managers at the beginning and end of the risk assessment process. In problem formulation, the Proposed Guidelines emphasize the complementary roles of assessors and managers in determining the scope and boundaries of the assessment and selecting endpoints that will be the focus of the assessment. The risk characterization section discusses estimating, interpreting, and reporting risks and applies an ecological perspective to recent Agency policy encouraging clear, transparent, reasonable, and consistent risk characterizations. The interface between risk assessors and risk managers is critical for ensuring that the results of the assessment can be used to support a management decision.