Micronucleus test for monitoring the genotoxic potential of the surface water of Luján River (Argentina) using erythrocytes of Lithobates catesbeianus tadpoles

Lujan river is a peri-urban ecosystem dominated by urban, industrial and agricultural discharges, receiving contributions from about one hundred streams along its path. The toxicological quality of the surface water in the middle course of the river was monitored by means of the micronucleus (MN) test, using peripheral erythrocytes of Lithobates catesbeianus premetamorphic tadpoles. This cytogenetic assay was performed to evaluate the effects of a particular domestic/industrial effluent poured continuously into the river, by incubating the larvae for 6 days to water samples from two sites: upstream and downstream the point where the effluent is dumped. The positive control was a cyclophosphamide solution. Five seasonal samplings were conducted between 2007 and 2008. The physicochemical analyses and the values of three water quality indices showed a highly polluted condition of the river. The MN frequency in the erythrocytes of the larvae exposed to the river samples was significantly higher than that of negative controls in all the cases and, in most samples, without differences with respect to the positive controls or even higher. There were no significant differences in the frequency of MN between the two environmental samples. The results allowed showing the genotoxic potential of the Lujan river water.