Evaluation of DNA damage in traffic police wardens of Pakistan due to cadmium and zinc.

Air quality in urban areas is generally poor especially at traffic intersections and roadsides due to continuous vehicular emissions comprising poly aromatic hydrocarbons, heavy metals, benzene, diesel soot etc. The objective of this study was to compare the primary DNA damage in traffic police wardens occupationally exposed to airborne Cd and Zn (exposed group) and educational institution with negligible exposure to airborne Cd and Zn (control group). Blood levels of Cd and Zn in traffic police wardens and control group were determined by Flame Atomic Absorption Spectroscopy (FAAS) and DNA damage was assessed by using Comet assay. The results of this study showed significantly higher amount of Cd (0.18±0.06mgL) and Zn (4.87±1.34mgL) in the blood of traffic police wardens as compared to control group and according to World Health Organization, these values are 18 and 3 times more to the permissible limit of Cd and Zn respectively in human blood. In addition, significantly higher numbers of DNA damaged cells (28±13%) were observed in traffic police wardens as compared to control group (3.6±2%). Comet tail length was found to be doubled (4.7±1.7μm) in traffic police wardens as compared to the control group (2±1.2μm). These results could be linked to the concentrations of Cd and Zn in blood of traffic police wardens. In conclusion, our results showed that accumulation of Cd and Zn was higher in traffic police wardens due to air pollution (Zn and Cd) and has more damaged DNA of traffic police wardens in Pakistan.