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(80-62) Detection strategies for the mutagenic potential of aquatic sediments and bioassay-directed identification of contaminants (ISIS). Vahl, Hans Heinrich*,1, Westendorf, Johannes1, 1 Dept. of Toxicology, Medical School, University of Hamburg, Vogt-Koelln-Str. 30, Hamburg, Germany ABSTRACT- Concern has been growing about potential adverse effects of genotoxins on aquatic biota and public health through contamination of drinking water supplies, recreational waters or edible aquatic species. In the aquatic environment, toxic compounds including many genotoxic agents are accumulated in sediments and suspended particulate matter. Genotoxicity testing of environmental samples requires a highly sensitive assay with high specificity. Three bacterial genotoxicity assays (Salmonella microsome assay, Ara forward mutation assay, and umu assay) were extensively applied to a variety of different aquatic samples (river and lake suspended solids, sediments and water, marine sediments, and drinking water). The two mutagenicity assays (Salmonella and Ara assay) proved to be most sensitive, the Ara assay being more sensitive to many samples than the Salmonella assay. In addition to sediment extraction procedures, a solid phase test was developed for the two mutagenicity assays in order to detect mutagenic effects of compounds that are not available to the extraction solvents used. This solid phase test showed an equal mutagenic potential as the extraction methods for the most samples, pointing out some samples with reduced or enhanced bioavailability of mutagens compared to the extraction methods. An accompanying chemical target analysis showed hot spots of anthropogenic contamination which were in accordance with the mutagenic potential found. A new approach is a bioassay-directed fractionation and identification network, ISIS (identification of sediment bound contaminants from North Sea and Baltic), one part of which is the Ara assay. This non-target analysis of sediment extracts is applied to those samples and fractions which show a mutagenic potential. The mutagenic potential of North sea and Baltic sediments was found in several fractions and sub-fractions, indicating combined effects in the unfractionated extracts. Compounds participating in these effects occur in the fraction where polyaromatic hydrocarbons (PAHs) and hetero-PAHs were found. Key words: comparison of genotoxicity assays, Arabinose resistance forward mutation assay, bioassay-directed chemical analysis, sediment contamination |
