Environmental Cleanup


Oregon environmental cleanup law and regulations require ecological risk assessments to determine what level a contaminated site needs to be cleanup to protect the environment. DEQ’s current Guidance for Ecological Risk Assessment was adopted in 1998, and updated in 2000 and 2001.

Ecological risk assessments consider the nature and extent of contamination, the presence of habitat for ecological receptors, current and reasonably likely future uses of land and beneficial uses of water, and other related factors. DEQ’s rules require that cleanup actions be based on the results of a baseline risk assessment, unless DEQ determines through screening that there could be no exceedance of acceptable risk levels. 
The current guidance provides a four-tiered risk assessment process that involves scoping, screening, baseline, and field baseline. The Level I Scoping process is intended to exclude sites from further ecological risk assessment that are obviously devoid of ecological important species or habitats, or where exposure pathways are obviously incomplete. Scoping involves a conservative qualitative determination as to whether there is reason to believe that ecologically important species or exposure pathways are potentially present on site or are in an area where facility-related contamination potentially migrated.

The Level II Screening process attempts to narrow the scope of subsequent site investigation and assessment activities by focusing on those contaminants and media posing potential risks to the environment. Level II guidance involves: 1) looking at site-specific information and scientific literature; 2) identifying site-specific ecological important wildlife and plants, exposure pathways between, and potential contaminants; and 3) conducting an initial evaluation of potential site-related risks. The guidance provides screening level values for soil, sediment, and water that are compared to site-specific concentrations to evaluate whether a site may to present unacceptable ecological risks. These values are not intended as cleanup levels.

The Level III Baseline risk assessment process provides the basis for determining the need for remediation and provides information necessary for the development of protective remedial alternatives. A baseline risk assessment involves a site-specific exposure analysis, ecological response analysis, and risk characterization. In practice, Level III Baseline risk assessments are rarely performed in Oregon.
The Level IV Field baseline assessment process is intended to refine, reduce uncertainties in, or validate the accuracy of the Level III assessment. Level IV involves site-specific analysis based on ecological field surveys, tissue analysis, or toxicity tests, rather than estimated and literature-derived data. In practice, a Level IV Field baseline assessment has not been performed in Oregon.
The current Guidance for Ecological Risk Assessment includes screening criteria for evaluating soil and surface water media, but does not contain criteria for sediment. In 2002, DEQ published comprehensive draft sediment guidance. However, that guidance was not finalized due to critical public comments. In 2007, DEQ adopted Guidance for Assessing Bioaccumulative Chemicals of Concern in Sediment.
DEQ recently signed the 2016 Regional Sediment Team’s Sediment Evaluation Framework, which provides a framework for assessing and characterizing sediment for dredge projects. DEQ is considering whether to incorporate SEF principles into future ecological risk assessment guidance.

Needs for guidance update

Stakeholders and DEQ staff have expressed concerns with DEQ’s current Guidance for Ecological Risk Assessment. The guidance has been said to be challenging to implement for several reasons. The guidance lacks clear criteria to direct timely and consistent decision-making. At times, the information collected following the current guidance does not provide risk assessors enough confidence to make risk assessment determinations. Nearly all ecological risk assessments conducted in Oregon have been limited to the Level I Scoping and Level II Screening, with only a few sites undergoing a Level III baseline assessment. The guidance includes some outdated screening level values that are not based on the latest science.

Consequently, DEQ has been working to identify guidance update needs and develop updated guidance. In 2014, DEQ convened the Ecological Risk Assessment Technical Workgroup, compromised of risk assessors and technical experts, to provide input aimed at improving the ecological risk assessment process in Oregon.

Technical workgroup

The workgroup was tasked with providing recommendations that:
  • Refine the Level I Scoping, Level II Screening, and Level III Baseline risk assessments process for terrestrial and aquatic habitats.
  • Consider the implications of adopting elements of the Washington Department of Ecology’s sediment standards for use in Oregon.
  • Consider whether DEQ should integrate the Regional Sediment Team’s Sediment Evaluation Framework, which was designed for dredging projects.
  • Evaluate if any rule changes should be considered to more effectively implement ecological risk assessments.

All of these efforts were not fully achieved.

In convening this workgroup, DEQ selected individuals with expertise in the technical details of ecological risk assessment who represent a range of entities both directly and indirectly affected by DEQ’s ecological risk assessment process.

External members:

  • John Toll, Windward Environmental
  • Madi Novak, Maul Foster & Alongi
  • Jeremy Buck, U.S. Fish and Wildlife Service, Oregon Fish & Wildlife Office
  • Heather Brunelle, Brunelle Environmental Consulting, LLC
  • Joe Goulet, U.S. Environmental Protection Agency
  • Arthur Buchan, Washington State Department of Ecology
  • Mark Dunn Lewis, Formation Environmental
  • Jeff Peterson, SLR International Corporation
Ex-officio members:
  • Jennifer Peterson, Oregon DEQ
  • Dan Hafley, Oregon DEQ

DEQ project team:

  • Bruce Gilles, DEQ Cleanup and Emergency Response Program Manager
  • Tiffany Johnson, Cleanup Program Policy Analyst

The workgroup’s final recommendations are contained in the Ecological Risk Assessment Technical Workgroup Recommendation Report (May 2017). This report is not intended to be guidance. The report is intended to provide overall high-level recommendations and examples for DEQ to consider as it develops updated guidance. Recommendations contained in the report are the opinion(s) of certain workgroup members, but not necessarily the opinion of all workgroup members or their respective organizations.

The workgroup developed a 3-staged terrestrial habitat ecological risk assessment framework and a 2-staged aquatic ecological risk assessment framework. The recommended framework is intended to provide more opportunities for sites to screen out or undergo cleanup actions earlier in the process, compared to current guidance, with the goal of making the process more cost-effectively and timely.

Key aspects of the framework includes criteria intended to improve data quality objectives, sampling approaches, data collection, screening level values, and decision points to help facilitate decision-making by obtaining high quality data to support decisions. The workgroup also recommends terrestrial habitat be excluded from further ecological risk assessment where the local land use designations does not require conservation or the habitat is smaller than 0.5-acre. Neither the land use nor habitat size exclusion applies where threatened and endangered species or critical habitat is potentially present on-site, or the site has a green overly zone designation. The recommended aquatic framework involves an initial habitat assessment, detailed habitat and ecological receptor surveys, and site modeling. The workgroup also recommends a Net Environmental Benefit Analysis be incorporated into the process to weigh cleanup alternatives and that DEQ allows for the use of Incremental Sampling Methodology to assess risks. 

The workgroup recommends DEQ conduct rulemaking to:

  • Revise the acceptable risk level for non-threaten and endangered species to replace the probability element of the rule with an approach focused on population exposure-response effect levels.
  • Revise the ecological benchmark value definition from a no-observed-adverse-effect-level and lowest-observed-adverse-effect-level to an exposure-response effect level.
  • Revise the rule to specifically allow use of net environmental benefit analysis. 

Next steps

DEQ is currently considering the workgroup’s recommendations and stakeholders’ comments to develop interim policies and updated guidance.


Tricia Atkins, Cleanup Grants and Guidance Coordinator