Geno and cytotoxicologic assessment of wastewater effluents with mussel micronucleus assay and with flow cytometric sperm toxicity assay a comparison

Abstract

Several pharmaceutical drugs have potential harmful effect on wildlife such as aquatic toxicity, genotoxicity, or endocrine disruption effect. Removal rates of pharmaceuticals from municipal sewage during waste water treatment is questionable, several studied drugs are insufficiently or not removed while passing through the sewage treatment plants (STP).The analytical monitoring of potentially harmful drugs and especially drug residues in influent and effluent of STP are rather costly and not always possible on a day to day basis. Toxicity bioassays, on the other hand, are relatively cost-effective short-term tests, estimating the aggregate genotoxicity of the samples on different taxonomic levels. In our study the cyto-and genotoxicity of the pre-treated potentially pharmaceutical containing influent and the effluent sample of a Hungarian STP were estimated with mussel (Unio pictorum) micronucleus (MN) assay and flow cytometric boar spermatozoa assay. The influent induced in the flow cytometric assay significant changes in mitochondrial transmembrane potential, oxidative DNA lesions and DNA fragmentation, but no significant genotoxic effect was detected by the MN assay. These results point to deficiencies of present wastewater treatment systems and remind us to choose carefully among available toxicity assays.