Release of hazardous substances at a contaminated site and subsequent dispersion into the environment may cause adverse effects to living organisms, habitats, and natural resources. Based on technical policy decisions potentially affected communities and major feeding guilds as well as their representative species can be identified and characterized.
Receptor: Ecological receptors includes any living organisms other than humans, the habitat which supports such organisms, or natural resources which could be adversely affected by environmental contaminations resulting by a release at or migration from a site. Typical receptor categories may be:
Habitat: Ecological habitats are defined as area or type of environment in which organisms and biological populations normally live or interact.
Natural Resources: Natural systems with intrinsic value to the public, regardless of actual current or planned future use of the resource such as species and communities that are important in maintaining the integrity and biodiversity of the environment.
Chemical Stressor: Contaminant that can induce an adverse ecological response
The identification and characterization of relevant ecological receptors and habitats that are valued at a site based on technical policy decisions, such as:
§ Special protection of species or communities by law or regulations,
§ Commercially or culturally important resources,
§ Communities of regional or national importance,
§ Communities with high aesthetic quality,
and is dependent upon site-specific factors allowing that a chemical stressor contacts an ecological receptor long enough and at a sufficient intensity to cause an adverse effect.
A detailed identification and characterization of ecological receptors consists of information on the identity of communities (e.g., soil invertebrates, benthic invertebrates) and major feeding guilds (e.g., omnivorous mammals, piscivorous birds) and their representative species, which are supported by habitats on an affected property. The existence of relevant receptors indicates the potential to be exposed by a released contaminant. But it does not imply that a receptor is adversely affected.
Ecological communities are a collection of plant and animal populations living in the same habitat in which the various species interact with one another. These communities consist of soil invertebrates, terrestrial vegetation, benthic invertebrates, water column invertebrates, algae, and rooted aquatic vegetation.
The designation "feeding guilds" refers to broad groups of related ecological receptors (e.g., piscivorous birds) that represent the variety of species potentially exposed to contaminants at an affected property. Feeding guilds are based on a shared function within an ecosystem (i.e., same feeding strategy), similar potential for exposure, and physiological and/or taxonomic similarity. Identification and characterization of these ecological receptors is used to define food webs specific to potentially impacted habitats.
Representative species, also called “measurement receptors”, may not actually occur at the affected property, but may be used to represent those within the feeding guild or community that may feed on an affected property. The selection of representative species or measurement receptors based on several factors, such as:
Examples of data sources and general information available for identification of ecological receptors are:
American Society for Testing and Materials (2002):
Guide for Risk-Based Corrective Action for Protection of Ecological Resources.
for Ecological Risk Assessment at Hazardous Waste Sites and Permitted
Facilities Part A. Overview.
Department of Toxic Substances Control. Human and Ecological
Efroymson, R.A., G.W. Suter II, B.E. Sample and D.S. Jones (1997):
Remediation Goals for Ecological Endpoints.
Suter, G.W., II. (1995):
Guide for Performing
Screening Ecological Risk Assessments at DOE Facilities.
for Conducting Ecological Risk Assessments at Remediation Sites in
Exposure Factor Handbook. Office of Research and Development.
Ecological Risk Assessment
Guidance for Superfund: Process for Designing and Conducting Ecological Risk
Assessments. Interim Final. Environmental
for Ecological Risk Assessment.
Risk Assessment Forum.