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Ecological Risk Assessments

Oregon DEQ is pleased to release Conducting Ecological Risk Assessments, September 2020 to aid cleanup site decisions. This directive explains DEQ's expectations for addressing ecological risk in accordance with Oregon Revised Statute (ORS 465.315(2)(a)) and Oregon Administrative Rule (OAR 340-122-0084(3)), and features the following key updates to DEQ's previous guidance (Guidance for Ecological Risk Assessment: Levels I, II, III, IV, April 1998, rev. December 2001): 
  • Re-structures the guidance into an Internal Management Directive format,
  • Streamlines the scoping section and exclusionary criteria, including the de minimis exclusion,
  • Updates ecological risk-based concentrations,
  • Provides clarity about the risk calculation process, specifically regarding cumulative risk and how to address sites of relatively low-medium complexity, and
  • Includes a companion internal management directive on decision unit characterization.
DEQ engaged a variety of external technical experts while developing this update, and welcomes continuous feedback for a clear and effective risk assessment process. The DEQ Cleanup Program will reference and treat this directive as a living document with purposeful tracking of stakeholder feedback to support process relevancy and consistent implementation.


Blair Paulik
Project Manager – Toxicologist