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EPA EcoBox

Phases of ERA - Risk Characterization

Risk characterization

Risk CharacterizationRisk characterization is the final phase of an ERA and is the culmination of the planning, problem formulation, and analysis of predicted or observed adverse ecological effects related to the assessment endpointsHelpassessment endpointsAn explicit expression of the environmental value to be protected, operationally defined as an ecological entity and its attributes.. During the risk characterization phase, risk assessors:

Risk managers use risk assessment results, along with other factors (e.g., economic or legal concerns), in making risk management decisions and as a basis for communicating risks to interested parties and the general public. The Guidelines for Ecological Risk Assessment (U.S. EPA 1998) note that the interface among risk assessors, risk managers, and interested parties during planning at the beginning and communication of risk at the end of the risk assessment is critical to ensure that the results of the assessment can be used to support a management decision.

After completion of the risk assessment, risk managers may consider whether follow-up activities are required. They may decide on risk mitigation measures, and then develop a monitoring plan to determine whether the procedures reduced risk or whether ecological recovery is occurring. Managers may also elect to conduct another planned tier or iteration of the risk assessment if necessary to support a management decision.

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Phase 3 of the ERA: Risk Characterization


Integrate exposure and stressor response profiles to evaluate the likelihood of adverse ecological effects associated with exposure to stressor(s) that includes discussion of lines of evidence and adversity of effects.

Who is involved?

Risk assessor(s), risk manager(s), and interested parties



Source: U.S. EPA 1998

The risk characterization phase within the overall ecological risk assessment process is illustrated below (adapted from U.S. EPA, 1998).

Planning/Problem Formulation

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  • U.S. EPA, 1998
  • U.S. EPA, 2012

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