engleski

Genotoxic properties of coagulant developed by using red mud and waste base as raw materials

Water extracts of the coagulant produced from red mud and waste base, and the waste mud remaining after waste water treatment by this new product, were studied in order to confirm its non-toxicity, prior to commercial production and usage and also to discover safe wasy for the handling and disposal of the remaining waste material. For the toxicity investigation, the determination of frequency of the cell survival, Ames assay, micronucleus assay and cell proliferation (expressed as mitotic index) were used. The same techniques were employed for the toxicity testing of the different concentrations of metal salts (zinc and lead nitrate) because these two elements were present in the high amounts in waste water treated with new coagulant. Two strains of Salmonella typhimurium, TA98 and TA100, were used for cytotoxicity assay and Ames assay, while cytogenetic investigations were performed on human peripheral blood lymphocytes. Water extracts of the coagulant and its waste mud were not cytotoxic or mutagenic for bacterial strains in presence/absence of metabolic activator. Negative results were obtained when cytogenetic assays were conducted. Lead nitrate was not cytotoxic on bacterial strains in the concentration range of 1-100 mg/mL, while zinc nitrate was cytotoxic at concentrations higher than 25 mg/mL. The results of Ames assay for nontoxic concentrations of these metals were negative. The number of micronuclei was significantly increased after the treatment lymphocytes in whole blood with 100 mg/mL of zinc nitrate, as well as 10 and 100 mg/mL of lead nitrate. Linear dose-dependent increases were obtained for both salts. Simila results were found on the basis of mitotic index.

genotoxicity; red mud; Salmonella typhimurium; Ames test

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