Modified and activated clinoptilolites ameliorate the cadmium and lead-induced genotoxicity in eukaryotic cells

The present research aimed to evaluate the potential of modified and activated clinoptilolite to mitigate the genotoxic effects of two heavy metals, lead (Pb) and cadmium (Cd), on a model system, Saccharomyces cerevisiae. The sodium-modified and activated clinoptilolites were kindly provided by prof. Yana Tzvetanova-Institute of Mineralogy and Crystallography "Acad. Ivan Kostov", Bulgarian Academy of Sciences. The material was collected from the volcanogenic sedimentary deposit "Beli Plast" (Eastern Rhodopes, Bulgaria). The 4- and 24-h adsorption capacity of the clinoptilolites was tested for the following solutions: PbCl₂ at a concentration of 0.5 mM (LD₂₀), CdCl₂-0,02 (LD₂₀), 0,04 (LD₅₀), 0,06 (LD₈₀) mM_, and a combination of both metals. Saccharomyces cerevisiae was used as a model organism. Cell survival studies revealed genotype-specific response to various Cd concentrations. Furthermore, data are obtained regarding the safety of the tested clinoptilolites at the cellular level. The adsorption capacity of the clinoptilolites was more pronounced for CdCl₂ than for PbCl₂. Based on measurements of superoxide anions and DNA double-strand breaks, effective adsorption was observed at both adsorption times. The heavy-metal-induced lipid peroxidation and reduced glutathione were also positively affected. Our results indicate that the 4-h clinoptilolite adsorption of a binary mixture Cd + Pb may lead to a reduction of the levels of superoxide anions and DNA double-strand breaks. Further experiments with different model systems may provide more detailed information on the positive effect of clinoptilolites on biological activity in heavy-metal decontamination strategies.