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Waste and Cleanup Risk Assessment

Ecological: Risk Characterization

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Risk characterization is the final step of the ecological risk assessment process and includes two major components: risk estimation and risk description.

Risk estimation combines exposure profiles and exposure-effects. Exposure profiles are descriptions of the patterns (spatial and temporal) of how particular contaminants come in contact with specific species of plants or animals. Exposure-effects are how contaminants affect (toxicity) the plants or animals that have come into contact with those contaminants.

Risk description provides information important for interpreting the risk results and identifies a level for harmful effects on the plants and animals that may have been affected. A key to risk description for Superfund sites is the documentation of environmental contamination levels that bound the threshold for adverse effects on the assessment endpoints (some characteristic of the plants and/or animals that are to be protected). The risk description can also provide information to help the risk manager judge the likelihood and ecological significance of the estimated risks.

Documents | EPA Links | External Links


  1. Ecological Risk Assessment and Risk Management Principles for Superfund Sites, Issuance of Final Guidance (PDF) (9 pp, 1MB,  About PDF)
    (October 7, 1999)

  2. Ecological Risk Assessment Guidance for Superfund: Process for Designing and Conducting Ecological Risk Assessments - Interim Final
    EPA 540-R-97-006 (June, 1997)
    These proposed guidelines are EPA's first Agency-Wide Ecological Risk Assessment Guidelines. They are broad in scope, providing general principles and providing numerous examples to show how ecological risk assessment can be applied to a wide range of systems, stressors, and biological spatial/temporal scales.

  3. Ecological Assessment of Superfund Sites: An Overview (PDF) (8 pp, 67K,  About PDF)
    Eco Update (December, 1991)
    This EcoUpdate bulletin describes the components of the ecological risk assessment process and how they fit into the Remedial Investigation/Feasibility Study process.

  4. ECO Update Bulletin Series
    EcoUpdates are a series of bulletins which provide information on various aspects of Ecological Risk Assessments, including toxicity testing, the role of the Biological Technical Assistance Group (BTAG), field studies, and screening level risk assessments.

  5. Environmental Protection Agency (EPA) Risk Characterization Program (1995)

  6. Guidance on Cumulative Risk Assessment. Part 1. Planning and Scoping
    Science Policy Council. U.S. Environmental Protection Agency, Science Policy Council (July 3, 1997).

  7. Guidance on Risk Characterization for Risk Managers and Risk Assessors (1992)

  8. Guidelines for Ecological Risk Assessment
    EPA/630/R-95/002F (April, 1998)
    These Agency-wide guidelines are provided to improve the quality and consistency of EPA's ecological risk assessments. The Guidelines expand on and replace the 1992 report Framework for Ecological Risk Assessment.

  9. Policy for Use of Probabilistic Analysis in Risk Assessment
    -- Guiding Principles for Monte Carlo Analysis
    -- Science Policy Council Handbook: Risk Characterization (PDF) (189 pp, 9MB,  About PDF)

  10. Supplement to Part A: Community Involvement in Superfund Risk Assessments (1999)
    The purpose of this guidance document is to provide the site team--risk assessor, remedial project manager (RPM), and community involvement coordinator--with information to improve community involvement in the Superfund risk assessment process.

  11. Risk Assessment Guidance for Superfund (RAGS) Volume III - Part A: Process for Conducting Probabilistic Risk Assessment (2001)

  12. Role of the Ecological Risk Assessment in the Baseline Risk Assessment (PDF) (2 pp, 180K,  About PDF) OSWER Directive 9285.7-17 (August 12, 1994)
    Describes the process and purpose of baseline ecological risk assessments, which, if required, come after screening level risk assessments.

  13. Role of Screening Level Risk Assessment and Refining COCs (Chemicals or Contaminants of Concern) in Baseline Ecological Risk Assessment (PDF) (4 pp, 364K,  About PDF) (2001)
    This EcoUpdate bulletin describes the process and purpose of the screening level ecological risk assessment, which is the first steps in a ecological risk assessment at a site, and how the list of COCs can be refined to include only those contaminants that may pose a risk.

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EPA Links

  1. EPA Region 5 Ecology Technical Center Ecological Risk Assessment
    Overview of ecological risk assessment process in Superfund, regional case studies, toxicity profiles, and regional contacts.


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External Links

  1. Oak Ridge National Laboratory - Ecological Risk Analysis: Tools and Applications

  2. Oak Ridge National Laboratory: Toxicology and Risk Analysis Section
    This EcoUpdate bulletin describes the components of the ecological risk assessment process and how they fit into the Remedial Investigation/Feasibility Study process.

  3. PCB Review by Heidi Fieldler  Link to EPA's External Link Disclaimer

  4. Spatial Analysis and Decision Assistance  Link to EPA's External Link Disclaimer
    Spatial Analysis and Decision Assistance is a freeware program developed at the University of Tennessee with funding from EPA, NRC, and DOE that provides comprehensive risk assessment tools in a spatial modeling environment. Risk assessors can use SADA to perform traditional risk assessment PRG calculations, PRG screens, and forward human health calculations for one or more contaminants. Users have complete control over all toxicological data, physical properties, and landuse/pathway exposure parameters to create site specific risk assessments. In addition, the risk models are integrated with SADA's spatial analysis tools, decision frameworks,and sample design strategies allowing users drive a risk based characterization from a preliminary initial sample design through a final feasibility study. In addition, SADA allows users to import their own site or region specific screening or decision threshold values separately from SADA’s own risk modeling tools.

  5. U.S. DOE’s Biota Dose Assessment Committee Provides a graded approach for evaluating radiation doses to aquatic and terrestrial biota

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