Selection of genotoxicity tests for risk assessment of effluents

Genotoxicity is one of the parameters within the whole effluent environmental risk procedure, an effect-based procedure developed in the Netherlands to supplement classical substance-specific risk assessment of effluents. To implement the genotoxicity parameter, one or more tests have to be selected for routine use on effluents. This paper deals with problems and considerations encountered during selection of genotoxicity tests. Tests were judged on: relevance, validation, detected genotoxic lesions, quantitative sensitivity, convenience, and cost-efficiency. Based on criterion detected genotoxic lesions and on criteria convenience and cost-efficiency, it is recommended to use at least a bacterial test which makes use of detection of the SOS pathway which is induced upon the occurrence of DNA damage. The criterion quantitative sensitivity is used in a laboratory study on effluent samples to select the most appropriate bacterial SOS pathway test. The range of detected genotoxic endpoints can be expanded by also including a more expensive test that detects clastogenesis and/or aneuploidy. In that case it seems wise first to establish the added value of such a test for the risk assessment of effluents, before deciding on further use. Furthermore, it is concluded that the presently available information on relevance and validation is of limited use for test selection. Finally, recommendations are made on test protocols and on pretreatment of effluent samples to optimize genotoxicity tests for effluent samples. Recommendations include data analysis, detection of the interference of cytotoxicity, extraction, the use of S9, concentration procedures, and filtration. © 2000 John Wiley & Sons, Inc. Environ Toxicol 15: 81–90, 2000