Occupational exposure and genotoxicity among Ethekwini Municipality petrol attendants.

Abstract

Background Benzene, a constituent of petrol, is classified as a Group 1 carcinogen. Once benzene enters the human body, its breakdown products, benzene oxide (BO) and 1.4 benzoquinone (BQ), have the ability to interact with DNA and proteins. Hydroquinone (HQ), a metabolite of benzene, has the ability to produce toxicity in the bone marrow once it interacts with phenol. The effects of genotoxicity are seen in a metabolizing gene (CYP2E1), detoxification genes (NQO1 and GSTT1), and in DNA-repair gene (XRCC1). Purpose To determine whether occupational exposure among eThekwini Municipality petrol attendants is associated with DNA damage. Methods This analytic cross sectional study included 151 participants that comprising of 75 high-exposed petrol attendants, 26 low-exposed workers from eight petrol stations within the city of Durban, and 50 office-based controls from University of KwaZulu-Natal. Researcher administered validated questionnaires were used to establish an association between DNA tail length via comet assay and the volume of petrol pumped in the past year, adjusting for various covariates through multivariate modelling. Results The median duration of employment in the petroleum industry was 4.5 years (range: 1-14 years) among the 26 low exposed and 5 years (range: 1-27 years) among 75 high-exposed pet-rol attendants. The median volume of petrol pumped by the 75 petrol attendants was 182 metric tons in the past year (range: 18-573 tons). The median tail lengths were 60.5μm (range: 18-149) for the high exposed, 89.5μm (range: 24-124) for the low exposed and 56 μm (range: 14-80) for the unexposed. Wilcoxin rank test, showed a statistically significant association between job title and tail length among the exposed and unexposed group. Mann Whitney test showed alcohol consumption to have a significant influence on the level of DNA damage. The multi-variate analysis showed a statistically significant association between job category, smoking, alcohol consumption and comet tail length. Conclusion Occupational exposure was associated with an increased comet tail length among the exposed group compared to the unexposed. Cumulative exposure of volume of petrol pumped over one year duration had no significant dose related risk and was not associated with an increase in DNA damage.