DNA single strand break analysis in mononuclear blood cells of petrol pump attendants.

DNA single strand breaks, including DNA adducts that lead to alkali-labile sites, were measured in peripheral mononuclear blood cells of 35 petrol pump attendants by alkaline filter elution. Blood samples from petrol pump attendants were taken on Monday and Friday. Additionally, DNA single strand breaks of smoking and non-smoking control persons were examined. For the smoking (n = 12) and the non-smoking controls (n = 20) a mean normalized elution rate of 1.49 +/- 0.52 (mean value +/- 95% confidence interval) and 1.32 +/- 0.28, respectively, was obtained. The difference between smoking and non-smoking controls was not statistically significant (U test). An increase in DNA single strand breaks from Monday to Friday was detected for non-smoking petrol pump attendants with a daily working time of more than 4 h at the pump station. Their mean normalized elution rate increased from 1.08 on Monday to 1.89 on Friday. This difference was statistically significant (P < 0.05; Wilcoxon test for paired data), although the 95% confidence interval was large on Friday (0.43 on Monday; 1.23 on Friday). However, no significant increase was found for non-smoking petrol pump attendants who were on duty for less than 4 h per day at the pump station. No statistically significant increase in DNA single strand breaks could be detected for smoking petrol pump attendants whether they were pumping gasoline for more or for less than 4 h per day.