Benzene Monitoring and S-Phenylmercapturic Acid Determination of Workers at Oil Sites in Congo-Brazzaville

The toxicity of benzene is well known, and its leukemia effect has established. It is a natural constituent of crude oil and the diseases related to its exposure are recognized as occupational diseases. Objective: To assess occupational exposure of benzene to workers in an oil and gas production company. Materials and Methods: Firstly, it was a descriptive, cross-sectional study which consisted of benzene atmospheric quantification in a sample individual measurement of a homogeneous exposure group of workers. Secondly, urinary assays of S-phenylmercapturic acid have been performed at the end of the shift in the selected workers. Results: The study has included 79 (47.88%) workers, 17 atmospheric samples were usable and 79 urinary assays at the end of the shift were performed. The average benzene concentration for all sites was 10 times lower than the regulatory average exposure value (1 ppm = 3.2 mg/m3): average: 0.122 pp, median: 0.053 ppm and range: 0.019 - 1.448 ppm. All 79 urinary assays of S-phenylmercapturic acid with a biological exposure index of less than 25 μg/g creatinine: mean: 0.70 μg/g creatinine, median: 0.52 μg/g creatinine and extends: 0.23 to 6.7 μg/g creatinine. Conclusion: Exposure was below to the limit value for benzene in both atmospheric metrology and biometrology. Therefore it is an occupational group with low exposure to benzene. Thus, the medical supervision will be adapted according to the potentially exposing tasks.