DNA damage in workers exposed to lead using comet assay

Abstract

Lead (Pb) is a ubiquitous and toxic metal. Secondary Pb recovery unit workers are prone to possible occupational Pb exposure. Hence, this investigation was conducted to assess the genotoxic effect of Pb exposure in these workers. In the study, 45 workers were monitored for DNA damage in blood leucocytes. Simultaneously 36 subjects were used as control group in this study. All the subjects were estimated for Pb content in whole blood by ICP-MS. The alkali single cell gel electrophoresis assay (comet assay) was adopted for detecting the DNA damage. The air inside the premises of the unit had Pb concentrations of 4.2 μg/m 3. The level of DNA damage was determined as the percentage of cells with comets. The mean Pb content was found to be significantly higher in the study group (248.3 μg/l) when compared with the controls (27.49 μg/l). Significantly more cells with DNA damage (44.58%) were observed in the study group than in the control persons (21.14%). Smoking had a significant effect on DNA damage in the control group whereas an insignificant effect was noticed in the exposed workers. Study as well as the control group failed to show a significant effect on DNA damage with age ( P>0.05). Pb content and years of exposure significantly correlated with DNA damage in the study group ( r=0.602, r=0.690; P<0.01). The increased levels of DNA damage observed in the exposed workers, justifies the use of the comet assay for the evaluation of genotoxic effects in humans exposed to Pb.