Level of DNA Damage in Lead-Exposed Workers

Lead plays a significant role in modern industry. This metal is related to a broad range of physiological, biochemical and behavioural dysfunctions. The genoto-xic effects of lead have been studied both in animals and humans in in vitro systems but results were contradictory. The aim of this study was to investigate the association between DNA damage and occupational exposure to lead in workers. The study population consisted of 62 employees of metalworks exposed to lead in the southern region of Poland. The control group consisted of 26 office workers with no history of occupational exposure to lead. The concentration of lead (PbB) and zincprotoporphyrin (ZPP) in blood samples were measured. The DNA damage was analyzed in blood lymphocytes using alkaline comet assay. The level of DNA damage was determined as the percentage of DNA in the tail, tail length and tail moment. The lead exposure indicators were significantly higher in lead exposed group: PbB about 8.5 times and ZPP 3.3 times. Also, the percentage of DNA in the tail (60.3 ± 14 vs. 37.1 ± 17.6), comet tail length (86.9 ± 15.49 vs. 73.8 ± 19.12) and TM (57.8 ± 17.82 vs. 33.2 ± 19.13) were significantly higher in the study group when compared with the controls; however, the difference between the subgroups was only 5-10%. Years of lead exposure positively correlated with all comet assay parameters (R=0.21-0.41). Both mean and current PbB and ZPP were correlated with tail DNA % and TM (R = 0.32; R=0.33; R=0.24; R=0.26 and R=0.34; R=0.33; R=0.28 and R = 0.28, respectively). This study shows that occupational exposure to lead is associated with DNA damage and confirmed that comet assay is a rapid, sensitive method suitable for biomonitoring studies.