Chromosomal aberration and single cell gel electrophoresis (Comet) assay in the longitudinal risk assessment of occupational exposure to pesticides

In recent years the use of pesticides in agriculture has been increasing st eadily, At present there are more than 1000 chemicals classified as pestici des. Therefore, the widespread use of pesticides and their potential geneti c hazard suggests that evaluation of their genotoxicity should be extended using the newer assays now available. In the present study chromosomal aber ration analysis and the alkaline single cell gel electrophoresis (Comet) as say were used to evaluate the extent of DNA damage and DNA repair in periph eral blood lymphocytes of subjects employed in pesticide production, In ord er to determine possible primary genotoxic effects in workers blood samples were taken after an 8 month long period of exposure to a complex mixture o f pesticides. To detect the possible occurrence of DNA repair in lymphocyte s of the same subjects the second blood sample was taken after an 8 month l ong period of absence from the pesticide exposure zone. Regardless of the p eriod of sampling, in the exposed group statistically significantly increas ed numbers of aberrant cells, chromatid and chromosome breaks, acentric fra gments and dicentric chromosomes compared with the controls were found. Aft er the workers had spent 8 months out of the pesticide exposure zone the nu mber of aberrant cells and all types of chromatid and chromosome aberration s decreased significantly compared with sampling after the high exposure pe riod, but it still remained significantly higher in comparison with the con trol group. After the period of high exposure to a mixture of pesticides st atistically significantly increased levels of DNA damage in the Comet assay in terms of tail length and tail moment were found. After the workers were removed from production for 8 months both Comet assay end-points decreased significantly compared with the first sampling point, but they remained in creased compared with the control.