Tri-Service Remedial Project Manager's Guide for Ecological Risk ...

Conceptual Model: 1 A series of working hypotheses of how the stressor might affect ecologicalcomponents. A description of an ecosystem or ecosystem components potentially at risk, andthe relationships between Measurement and Assessment Endpoints and exposure scenarios.Control: 1 A treatment in a toxicity test that duplicates all the conditions of exposure treatmentsbut contains no test chemical. The control is used to determine the response rate expected inthe test organism(s) in the absence of the test material.Correlation: 1 An estimate of the degree to which two sets of variables vary together.Caution: High correlation between a stressor and the response of an organism does notnecessarily mean cause and effect.Deposition: 1 The dispersion of any material by natural processes such as wind or water or bylying, placing, or throwing down the material.Depuration: 2Loss of a material from an organism due to elimination and degradation.Dose: 2 A measure of exposure. Examples: (1) the amount of chemical ingested. (2) theamount of chemical actually taken up or absorbed.Dose-Response Curve: 1 A curve, plotted as Dose versus Response, that is similar toconcentration-response curve except that the dose (i.e., the amount of chemical ingested, takenup, or absorbed) is known.EC x (Effective Concentration x ): 3 The concentration of a chemical that is estimated to cause atoxic effect on x% of test organisms. The duration of the exposure must be specified. Effectsmay be lethal or sublethal.Ecological Component: 1 Any part of the ecosystem, including individuals, populations,communities, and the ecosystem itself.Ecological Risk: 1 In the context of risk assessment, the expected frequency or probability ofundesirable (or “unacceptable adverse”) ecological effects resulting from exposure to known orexpected stressors.Ecological Risk Assessment: The qualitative or quantitative appraisal of the actual or potentialimpacts of stressors (i.e., contaminants) on plants and animals at a site, other than human anddomesticated species.Ecosystem: 1 The biotic community and abiotic environment within a specified location and time,including the chemical, physical and biological relationships among the biotic and abioticcomponents.Ecotoxicology: 2communities.The study of toxic effects on non-human organisms, populations, andEEC (Estimated or Expected Exposure Point or Environmental Concentration): 1 Theconcentration of material estimated as being likely to occur in environmental media to whichorganisms are exposed.Key Terms - 3