An ecological risk assessmentecological risk assessmentThe application of a formal framework, analytical process, or model to estimate the effects of human actions(s) on a natural resource and to interpret the significance of those effects in light of the uncertainties identified in each component of the assessment process. Such analysis includes initial hazard identification, exposure and dose-response assessments, and risk characterization. is the process for evaluating how likely it is that the environment may be impacted as a result of exposure to one or more environmental stressors such as chemicals, land change, disease, invasive species and climate change.

An ecological risk assessment includes 3 phases:

• Planning - Planning and Scoping process
  EPA begins the process of a Ecological risk assessment with planning and research.
   
• Phase 1 - Problem Formulation
  Information is gathered to help determine what, in terms of plants and animals, is at risk and what needs to be protected.
   
• Phase 2 - Analysis
  This is the determination of what plants and animals are exposed and to what degree they are exposed, and if that level of exposure is likely or not to cause harmful ecological effects.
   
• Phase 3 - Risk Characterization
  Risk characterization includes two major components: risk estimation and risk description. "Risk estimation" combines exposure profiles and exposure-effects. "Risk description" provides information important for interpreting the risk results and identifies a level for harmful effects on the plants and animals of concern.

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Uses of Ecological Risk Assessments

Every day, people face questions about environmental concerns, many of them related to plants, animals, ecosystems as a whole, and how we interact with them.

These questions may be about potential risks such as impacts on the aesthetic value of a place due to physical alterations, effects of pollution on endangered species, or the consequences of long-term release of contaminants to an ecosystem. For example:

• How would the construction of a dam impact fish populations in nearby water bodies?
• Can the residential or agricultural application of an insecticide end up harming an endangered bird species?
• Do contaminants in the environment from an abandoned industrial or mining facility significantly reduce the use of the site and to nearby areas?
• What is the risk of introducing a non-native oyster to an estuary?
• How does fertilizer runoff reduce oxygen levels in water bodies such as bays?
• Are some plants or animals more likely to be susceptible to environmental stressors because of factors such as age, genetics, body size, or differences among species?

A key part of EPA’s mission is understanding the potential effects of stressors such as those described above and managing risks from them in order to protect the health of the natural environment, and the natural resources that people rely on.

At EPA, ecological risk assessments are used to support many types of actions, including:

• regulation of hazardous waste sites, industrial chemicals, and pesticides;
• or the management of watersheds or
• other ecosystems affected by multiple chemical, physical, or biological stressors.

Ecological risk assessments can be used to predict the likelihood of future effects (prospective) or evaluate the likelihood that effects are caused by past exposure to stressors (retrospective).

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