The project was a feasibility study of the effectiveness of a mammalian cell cytotoxicity assay and a mammalian cell mutagenesis assay for monitoring the toxicity and mutagenicity of influent and effluent wastewater at treatment plants. In the cytotoxicity assay, ambient samples of raw sewage were substantially cytotoxic but secondary effluent samples were not toxic enough to establish an LC50 value. In the mutagenesis assays, the early Mill Creek ambient samples of raw and secondary effluent were mutagenic but the ambient samples from the later Mill Creek sampling were not mutagenic. The data suggest that the cytotoxic and mutagenic activities of the ambient waste-water samples are near the limits of detection of the two assays. When the samples had high biological activity, there was an observable response. With the exception of alkaline extracts of the second Mill Creek samples, all concentrated extracts from the samples were cytotoxic and mutagenic to some degree. The single Muddy Creek influent was not as toxic or mutagenic as the Mill Creek influent on either sampling date.

"EPA 600/2-89/031." References. "June 1989." "Dolloff F. Bishop, project officer." Microfiche.