ECOTOXICOLOGICAL STUDIES USING MODIFIED AMES BIOASSAY

Health and environmental risk assessment of river and wastewaters base d on single chemicals is limited by the number of chemicals that can b e identified and to those chemicals for which toxicity and mutagenicit y data exist. In this study Salmonella/microsome mutagenicity assay wa s evaluated as a potentially useful biomonitoring system for river wat er and wastewater. Standard assay was modified to allow testing of up to 2.5 ml of nonconcentrated water sample and by introducing 90 minute s of preincubation. Mutagenic activity of nonconcentrated samples was compared to the mutagenic activity of XAD-2 extracts of the same sampl es. Eighteen river water samples, two wastewater samples and one sampl e of water leaking from municipal waste dump were tested. Mutagenicity was detected in three nonconcentrated river water samples, both nonco ncentrated wastewater samples and in the sample of the water leaking f rom the municipal waste dump. The mutagenic profiles of nonconcentrate d samples were different from the mutagenic profiles of the XAD-2 extr acts. The modified method was sensitive enough to detect mutagens pres ent in more polluted river water (class IV), in wastewaters and in wat er leaking from the municipal dump. For the assessment of the impact o f the mutagenic river and wastewaters on the environment, calculations from the results of nonconcentrated samples should be used as it seem s that calculations from the results of the extracts are leading to th e underestimation of mutagenic potency. Mutagenic profiles of the extr acts are a useful guide for further chemical and biological analysis t o trace the sources of the mutagens and to introduce measures to reduc e them. Copyright (C) 1996 IAWQ.