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EPA EcoBox

Phases of ERA - Analysis



According the Guidelines for Ecological Risk Assessment (U.S. EPA 1998), during the analysis phase, risk assessors:

The products from the analysis phase are two profiles, one for exposure and one for stressor response. These products provide the basis for risk characterization.

Appendix D to the 1998 Guidelines for Ecological Risk Assessment (U.S. EPA, 1998) provides examples of the types of products developed during the analysis phase.

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Exposure Characterization

Exposure characterization describes sources of stressors, stressor distribution in the environment, and ecological receptor contact or co-occurrenceHelpco-occurrenceExposure that is not the result of direct contact with a stressor, but occurs when a stressor, due to its spatial or temporal proximity to a receptor, results in significantly altered receptor response. with stressors.

The goal of the exposure characterization step is to produce a summary exposure profile that:

The exposure profile provides a complete picture of how, when, and where exposure occurs or has occurred. It is developed by evaluating sources and releases of the stressor, distribution of the stressor in the environment, and extent and pattern of contact with the stressor.

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Ecological Effects Characterization

Ecological effects characterization evaluates stressor-response relationships or evidence that exposure to stressors causes an observed response. To characterize ecological effects, the assessor:

The goal of the ecological effects characterization step is to produce a summary stressor-response profile. The profile is used to identify receptors that are affected by stressor and characterize the nature and intensity of the effect(s).

Where appropriate, the stressor-response profile will identify the time scale for recovery and causal information that links the stressor with observed effects.

The stressor-response profile also describes how changes in measures of effects relate to changes in assessment endpoints and discusses the uncertainties and assumptions associated with the analysis.

The exposure profile is combined with a stressor-response profile to estimate risks.

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Phase 2 of the ERA: Analysis


Provide the information necessary for determining or predicting ecological responses to stressors under exposure conditions of interest. Analysis connects problem formulation with risk characterization.

Who is involved?

Risk assessor(s) (in consultation with Risk Manager)



Source: U.S. EPA 1998

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

Planning/Problem Formulation


  • U.S. EPA 1998.

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