Detection of DNA damage in lead (Pb) exposed city traffic wardens in Pakistan

Lead (Pb) is one of the toxic metals and is commonly used in industries. It affects multiple systems and has role in the production of reactive oxygen species (ROS). The objective of the present study was to determine Pb levels and to detect DNA damage in traffic wardens of Lahore, Pakistan. A total of 90 subjects were selected including 60 traffic wardens working in field and 30 working in administrative zones. The wardens who were working in field were considered as cases (exposed by the lead polluted environment) while the wardens in the administrative offices (less exposed to polluted environment) were labeled controls. Venous blood samples were collected for Pb and comet assay. In cases, the levels of Pb were 18.76±8.84 μg/dL (Mean±SD) that was higher than controls, 12.00±3.552 (p 0.000). Tail moment (TM) in cases (0.583±1.960) and controls (0.0453±0.108) significantly differed (p 0.004). There was no change in %DNA in tail and head (p 0.136). The parameters for DNA damage assessment including Comet length (CL) and Tail length (TL) were also found higher in cases than controls. Correlation of lead with other biochemical parameters including liver functions, renal functions and lipid profiles was carried out to assess the various organs/systems. The correlation was established with creatinine showing statistically significant value (p 0.019). Our findings elaborate a mild raise of lead levels in exposed group. There was no significant difference in comet length between cases and controls. Also, minor or no differences were observed in different biochemical parameters between cases and controls. These findings demonstrate dramatic improvement over the results from the study done previously in 2005 and may be attributed to the success of having lead-free petroleum as motor fuel.    Key words: Lead, DNA damage, single cell gel electrophoresis, traffic wardens.