Navy Human Health Risk Assessment Web Site

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Glossary

Select a letter from the list below to view other definitions.

A B C D E F G H I L M N O P R S T U V W

Ecological Receptor
see Receptor.

Ecological Risk
In the context of risk assessment, the expected frequency or probability of undesirable (or unacceptable adverse) ecological effects resulting from exposure to known or expected stressors (EPA 1997).

Ecological Risk Assessment (ERA)
The process that evaluates the likelihood that adverse ecological effects may occur or are occurring as a result of exposure to one or more stressors.

Ecological Risk Assessment Technical Assistance Team (ERTAT)
The team established by the Navy to provide technical support, including document review, to Navy sites conducting ecological risk assessments.

Ecology
The science that studies the relationship of living organisms to each other and to their environment.

Ecosystem
The biotic community and abiotic environment within a specified location and time including the chemical, physical and biological relationships among the biotic and abiotic components (EPA 1997).

Ecotoxicity Profile
Describes the toxic mechanisms of action for the exposure routes being evaluated and the dose or environmental concentration that causes a specified adverse effect to biota.

Ecotoxicology
The science that deals with toxic effects on nonhuman organisms, populations, and communities.

Environment
Water, air, land, and all plants and man and other animals living therein, and the interrelationships which exist among them (ORNL 1999a). The CERCLA definition is defined as: (1) navigable waters, the waters of the contiguous zone, and the ocean waters of which the natural resources are under the exclusive management authority of the United States under the Magnuson-Stevens Fishery Conservation and Management Act; and (2) any other surface water, ground water, drinking water supply, land surface or subsurface strata, or ambient air within the United States or under the jurisdiction of the United States.

Environmental Restoration (ER)
Process of assisting the recovery and management of the environment to pre-violation conditions.

Exposure Estimate
Either the maximum environmental concentration or the calculated dose estimate, when divided by the screening ecotoxicology value provides the hazard quotient.

Exposure Evaluation (or Assessment)
The process of measuring or estimating the intensity, frequency, and duration of exposure to an agent currently present in the environment; or estimating hypothetical exposures that might arise from the release of new chemicals into the environment (ORNL 1999a).

Exposure Pathway
The course a chemical or physical agent travels from a source to an exposed organism. Each exposure pathway includes a source, an exposure point, and an exposure route. Transport/exposure media (e.g., air, and water) also are included if the exposure point differs from the source (EPA 1997).

Exposure Routes
A point of contact/entry of a contaminant from the environment into an organism (e.g., inhalation, ingestion, dermal absorption) (EPA 1997).

Exposure Scenario
A set of assumptions concerning how an exposure takes place, including assumptions about the exposure setting, stressor characteristics, and activities of an organism that can lead to exposure (EPA 1992).

Last Modified: 02/27/2003

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