Petrol exposure and DNA integrity of peripheral lymphocytes.

Abstract

To determine the effect of petrol exposure on DNA integrity in peripheral blood lymphocytes among petrol attendants and a non-exposed comparison population. This cross-sectional study included 101 fuel station employees and 50 office-based non-exposed workers in Durban, South Africa. Participants were interviewed using a validated questionnaire. Genomic DNA was extracted from peripheral lymphocytes for the benzo(a)pyrene diol epoxide (BPDE)-DNA adduct assay (ELISA), and DNA damage was determined using the comet assay and reported as percentage tail DNA. The exposed (n=101) and non-exposed participants (n=50) varied with regard to age, housing, smoking, and proximity to industry and petrol stations. Among the exposed, the mean duration of employment in the fuel industry was 5.8years (SD=4.6), and among those pumping fuel (n=75), the mean metric tons of petrol pumped in the past 12months per worker was 199.2 (SD=88.9). The mean percentage tail DNA varied significantly between exposed and non-exposed groups: 23.8% (SD=13.3) and 8.1% (SD=1.8) (p<0.01), respectively. A significant difference existed between the groups for BPDE-DNA adducts: 30.0ng/ml (SD=12.7) and 18.1ng/ml (SD=18.2) (p<0.0001), respectively. Regression models, adjusting for cigarette smoking, age, and sex, showed a 16.5 greater percentage tail DNA among the exposed compared to non-exposed (95% CI11.8-21.1%), while the exposed group had a 12.9ng/ml greater increase in BPDE-DNA adducts has compared to the unexposed (95% CI7.2-18.7ng/ml). Cigarette smoking resulted in almost a 3.5% increase in percentage tail DNA. Our study adds to the literature that long-term, low-dose exposure to vehicular fuels is likely to result in altered DNA integrity and genotoxicity among petrol attendants. These results strengthen the case that these workers must be afforded appropriate protection to prevent serious adverse outcomes.