The use of genetic bioassays to evaluate the environmental quality in a region under the influence of urban waste in Guaíba lake basin (Brazil)

The mussel species Limnoperna fortunei was chosen as biomonitoring organism in Guaíba Lake Basin, based on population data, distribution, and sensitivity. Previous in vitro and in vivo studies studies with Single Cell Gel Assay (SCGA) and Micronuclei test (MN) on this freshwater mussel showed that it is successful in biomonitoring studies, especially in urban pollution monitoring. This study evaluated two sampling sites in the Guaíba Lake (Guaíba PC e Guaíba BR), near urban waste discharges, and a control site (Itapu ) insight a preserved area, using L. fortunei individuals. Comparing to the control site, the Guaíba BR sample induced DNA damage in haemocytes of mussels sampled both in situ and exposed to laboratory conditions, whereas MN only in in situ collected mussels. This sample also presented the only surface water mutagenic result by Salmonella/microsome assay with TA98 in the presence of metabolic activation. Guaíba PC samples increased MN frequency in situ and in laboratory conditions comparing to the Itapu results. Metal influence seems to be less important than organic influence in genotoxic induction. These results confirm the strong urban influence in this region, showing that biomonitoring is a powerful tool to detect this kind of contamination in water bodies.