4.1 This guide assumes that a decision has been made that an ecological risk assessment is required for a contaminated site. In some cases, this decision could be made before any site data are collected.

4.2 The selection of assessment endpoints (defined as ecological values to be protected) and measurement endpoints (ecological characteristics related to the assessment endpoints) is a critical step in conducting an ecological risk assessment. Endpoint selection identifies those effects which are ecologically significant and not merely those that are adverse, thus providing a more rational and defensible basis for making risk and remedial decisions.

4.3 This guide provides an approach for identifying, selecting and using assessment and measurement endpoints in an ecological risk assessment for a contaminated site. This guide has been developed because there is no universal, simple measure of ecological health analogous to measures used in human health risk assessment. Assessment and measurement endpoints have to be identified and selected from a variety of individual circumstances on a stressor-, ecosystem- and scale-specific basis. It is important to recognize that a diverse set of ecological endpoints could be required for a specific site.

4.4 This guide is intended to be used primarily by a biologist, ecologist, ecotoxicologist, or a team of environmental scientists during problem formulation and work plan development prior to initiating data collection activities at a contaminated site (3-8, 10).

4.5 Ecological risk assessment is usually an iterative process. In many circumstances it proceeds as a series of tiers, that is, desktop/screening, preliminary, and detailed/focused phases. This guide can be used to refine or modify assessment and measurement endpoints developed in earlier phases of the process.

4.6 This guide can be used whenever assessment and measurement endpoints must be identified and selected following an initial or preliminary problem formulation/planning phase:

4.6.1 Analysis phase (exposure assessment, hazard/effects assessment, stress/dose-response assessment;

4.6.2 Risk characterization phase; or

4.6.3 Remediation phase and possible subsequent ecological monitoring.

4.7 This guide is intended to be used in the evaluation of baseline conditions (current and future) and in the evaluation of conditions resulting from remedial actions or corrective measures.

This guide deals with an approach to identification, selection, and use of ecological endpoints (both assessment and measurement endpoints) that are susceptible to the direct and indirect effects of both chemical and non-chemical stressors and agents associated with wastes and contaminated media at specific sites under current and future land uses. It does not address assessment and measurement endpoints for non-site specific studies (for example, chemical specific or regional risk assessments) or measurements in abiotic media (soil, water, or air). Conditions of the site and risk assessment that should be considered in identifying and selecting assessment and measurement endpoints include stressor characteristics, ecosystem types, spatial scale, temporal scale, ecological organization, and functionality/values. The following subsections present a partial listing of representative measurement endpoints: measurement endpoints representing ecosystem assessment endpoints, measurement endpoints representing community assessment endpoints, measurement endpoints representing population assessment endpoints, and measurement endpoints representing individual organism assessment endpoints. Other general considerations, desirable characteristics of assessment and measurement endpoints, candidate site-related ecological receptors, candidate assessment endpoints, specific steps in identifying, selecting and using assessment and measurement endpoints, addressing uncertainties in the identification and selection of assessment and measurement endpoints, documenting the selection of assessment and measurement endpoints.

1.1 This guide covers an approach to identification, selection, and use of ecological endpoints (both assessment and measurement endpoints) (1-8)² that are susceptible to the direct and indirect effects of both chemical and non-chemical stressors or agents associated with wastes and contaminated media at specific sites under current and future land uses. It does not address assessment and measurement endpoints for non-site specific studies (for example, chemical-specific or regional risk assessments) or measurements in abiotic media (soil, water, or air).

1.2 This guide addresses only the identification, selection, and use of assessment and measurement endpoints, not the full range of activities that occur in an ecological assessment or ecological risk assessment at a contaminated site (1, 3-8). These activities are addressed in other ASTM guides and references provided at the end of this guide.

1.3 This guide is intended to identify assessment and measurement endpoints to be used for screening, preliminary, focused, detailed, and quantitative ecological risk assessments conducted in a linear or iterative fashion (3, 8). This is a partial, incomplete listing of possible levels of assessment. In a tiered ecological risk assessment, it may be necessary to redefine ecological endpoints when planning to collect more data or when additional site data are obtained and evaluated.

1.4 This guide is intended to be used by trained biologists, ecologists, and ecotoxicologists familiar with risk assessment, and ecological and ecotoxicological concepts.

1.5 This guide (including Appendix X1) consists of a series of options or instructions and does not recommend a specific course of action or provide detailed guidelines to be followed at all sites. See 2.2.2 of Regulations Governing ASTM Technical Committees.³

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.