Standard Guide for Selection of Resident Species as Test Organisms for Aquatic and Sediment Toxicity Tests

Importancia y uso:

5.1 The USEPA's policy for whole-effluent monitoring stresses, an integrated approach to toxicity testing (1, 5) tests and other measures of toxicity, should be systematically employed and should be related to certain aquatic-system factors, such as the type of habitats available (benthic and water column), flow regime, and physicochemical quality of the site water and sediment. The determination of toxicity is generally accomplished with a few surrogate species for four major reasons: a regulatory agency can compare test results between sites and over time in order to help prioritize enforcement efforts, tests using these species are relatively inexpensive since the organisms can be cultured year-round under laboratory conditions, the reliability of test methods utilizing surrogate species is better established than for other species, and surrogate species are better integrated into toxicity identification evaluations than other species. For regulatory purposes, under the National Pollution Discharge Elimination System (NPDES), USEPA considers it unnecessary to conduct whole effluent toxicity tests with resident or indigenous species (6). An alternate testing procedure protocol is provided by USEPA for validating toxicity methods using species not already approved (6,7). In systems where surrogate species are not found, erroneous predictions might be obtained of environmental impact or water and sediment quality impairment based on toxicity tests using surrogate species (8).

5.2 This guide is intended to assist researchers and managers in selecting appropriate resident species for site-specific toxicity assessments. This guide could be used to select a resident species for use in predicting the potential toxic effects of a substance in certain types of aquatic environments. Another use might be for selecting a number of indigenous species from the aquatic community, that when tested, might indicate potential toxic effects of the test substance or material on the ecological integrity of that community. Selection of a suitable test species is very important because species might respond quite differently to toxic compounds (9). Species suggested as test organisms by regulatory agencies might not occur in the receiving waters of interest and their sensitivity to a toxic substance might not be representative of the sensitivity exhibited by resident species. Since aquatic ecosystem structure and function is often determined by a few key species (10, 11, 12, 13), toxicological tests with these resident species might be very important.

5.3 This guide can be used in the selection of representative test species for certain site-specific assessments, such as the Resident-Species Criteria Modification Procedure (1), the Recalculation Procedure (14), and ecological risk assessment studies.

5.4 This guide can be used as a general framework for researchers who desire to develop or modify existing toxicity test methods for previously untested species.

5.5 Researchers in countries other than the United States and Canada might obtain useful information from this guide regarding potential test species or test methods for sites of local interest.

Subcomité:

E50.47

Referida por:

E2455-25, E1706-25, E3163-24, E1367-03R23

Volúmen:

11.09

Número ICS:

13.060.45 (Examination of water in general)

Palabras clave:

aquatic toxicity testing; bioassessment; indigenous species; resident species; sediment toxicity testing; site-specific monitoring;