Mutagenicity and toxicity of water extracts from the Sora river area.

The present study was conducted on the waters of the Sora river and effluents entering to the river. The samples were extracted with XAD-2 resin at different pH and tested for mutagenicity with the modified Ames test using strains S. typhimurium TA98 and TA100. The majority of the mutagenic activity of the samples was found in the neutral pH fraction of the extracts. Strain TA98 in the presence of metabolic activation was the most sensitive condition of mutagenicity. Of the eleven sample extracts, six were positive; neutral fractions of the effluent from wastewater treatment plant, the water leaching from the municipal dump, the water from the lake lying beneath the dump and the untreated effluent, and acid fractions of two samples taken directly from the river. The water leaching from the municipal dump was also mutagenic and toxic without previous extraction. Mutagenic responses before and after extraction of this sample indicate that components responsible for mutagenicity were partly extracted in the neutral fraction. The toxicity of water samples and extracts was tested with Microtox assay, and acid fractions of the extracts were more toxic than the neutral fractions. Comparing the toxicity to the mutagenicity data indicates that components responsible for toxic and mutagenic response were at least partly separated between acid and neutral fraction respectively.