Evaluation of Chemical and Biological Methods for the Identification of Mutagenic and Cytotoxic Hazardous Waste Samples

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Abstract
To assist in the development of methods for identifying potentially hazardous wastes, we have conducted studies on the extraction of toxicants from several solid waste samples. The extracts were tested for toxicity by the Chinese hamster ovary (CHO) cytotoxicity test and for mutagenic potential in the Salmonella histidine reversion assay. A new technique was also employed that measured the mutagenicity of neat waste samples by coupling thin layer chromatography (TLC) with the Salmonella histidine reversion assay. The wastes selected for study were coke plant waste, herbicide manufacturing acetone-water effluent, and oil refining waste. Three extraction solvents—ethanol, dichloromethane (DCM), and dimethylsulfoxide (DMSO)—were chosen based on their solubility and compatibility with bioassay procedures. Each sample was divided into three parts and extracted with each of the three solvents separately. All extracts were tested in the Salmonella assay at five dose levels with five Ames tester strains in the presence and in the absence of an exogenous metabolizing system. The DMSO and DCM extracts were utilized for CHO cytotoxicity evaluations. The three neat waste samples and two extracts were assayed by the Salmonella/TLC technique. In addition to the biological assessments, the gross chemical parameters for each sample were determined. Results showed that coke plant waste and herbicide manufacturing acetone-water were mutagenic to S. typhimurium with the standard plate test. With the Salmonella/TLC technique, the coke plant waste was mutagenic and oil refining waste was both toxic and mutagenic. Oil refining waste was also toxic to CHO cells. Results of the gross chemistry determinations showed the three samples to have a wide range of solid content, total organic content, and extractables. Evaluation of the chemical extraction methods demonstrated few differences in extraction capabilities with respect to mutagenic activity.