Cytogenetic monitoring of occupationally exposed workers in a petroleum refinery

A monitoring study was carried out on petroleum refinery workers that are exposed to a wide range of petroleum-derived hydrocarbons and chemical substances (benzene, aliphatic and polycyclic aromatics hydrocarbons, hydrogen sulphide, sulphur dioxide and heavy metals) to investigate the risk of occupational exposure to carcinogens. In this project, a cytogenetic investigation (by using the cytokinesis-block micronucleus assay) was performed on a group of exposed subjects and on a control group adequately selected and matched for gender and age. Subjects were divided into two sub-groups: smokers and non-smokers to investigate the possible effects (synergistic/additive/antagonist) of smoke intake on DNA damage. Out of about 500 exposed subjects enrolled in the study, we selected by using a questionnaire proposed by the International Commission Protection against Environmental Mutagens and Carcinogens, and questions concerning the individual occupational exposure to benzene 61 male subjects (43 non-smokers, 18 smokers) (mean age = 39 years). Despite the security measures taken, the exposed group showed a significantly higher frequency of genetic damage (BNMN 7.3‰±4.9) when compared to the control group (BNMN 4‰±2.5) (p < 0.0001). Interestingly, the frequencies of BNMN found were significantly higher in exposed non-smokers (BNMN 8.9‰±4.9) than in exposed smokers (BNMN 3.7‰±2.00) (p < 0.0001) suggesting a possible protective role of smoking. These results are indicative of a potential genotoxic risk and corroborate the need to increase safety measures to avoid exposure. Acknowledgement: This research has been supported by Ministry of Public Health Project (PMS/024/2003) “Occupational benzene exposure: development of advanced biosensors for environmental monitoring”.