Genomic damage induced by the widely used fungicide chlorothalonil in peripheral human lymphocytes

Chlorothalonil is an important broad spectrum fungicide widely used in agriculture, silviculture, and urban settings. As a result of its massive use, chlorothalonil was found in all environmental matrices, with consequent risks to the health of terrestrial and aquatic organisms, as well as for humans. We analyzed the effects of chlorothalonil on human lymphocytes using in vitro chromosomal aberrations (CM) and micronuclei (MNi) assays. Lymphocytes were exposed to five concentrations of chlorothalonil: 0.600 mu g/mL, 0.060 mu g/mL, 0.030 mu g/mL, 0.020 mu g/mL, and 0.015 mu g/mL, where 0.020 and 0.600 mu g/mL represent the ADI and the ARfD concentration values, respectively, established by FAO/WHO for this compound; 0.030 and 0.060 mu g/mL represent intermediate values of these concentrations and 0.015 mu g/mL represents the ADI value established by the Canadian health and welfare agency. We observed cytogenetic effects of chlorothalonil on cultured human lymphocytes in terms of increased CM and MNi frequencies at all tested concentrations, including the FAO/WHO ADI and ARfD values of 0.020 and 0.600 mu g/mL, respectively, but with exception of the Canadian ADI value of 0.015 mu g/mL. Finally, no sexes differences were found in the levels of CM and MNi induced by different chlorothalonil concentrations. Similarly, the mitotic index and the cytokinesis-block proliferation index did not show any significant effect on the proliferative capacity of the cells, although at the chlorothalonil concentration of 0.600 mu g/mL the P-values of both indices were borderline.