ASSESSMENT OF OXIDATIVE STRESS AND ANTIOXIDANT STATUS AMONG PETROL STATIONS’ WORKERS EXPOSED TO BENZENE IN ZAGAZIG CITY

Abstract

Background: The main environmental source of benzene exposure is vehicle exhaust emissions and evaporation losses of petrol at petrol filling stations. Activation of benzene and its reactive metabolites leads to continuous production of reactive oxygen species (ROS), which damages DNA, RNA, and proteins by chemical reactions. Aim & Objectives: This study aims to promote health of petrol stations’ workers occupationally exposed to benzene in their daily work with the following objectives: (1)Assess trans,trans-muconic acid (ttMA) level in urine as a biological marker for benzene exposure (2) Estimate the extent of oxidative stress by measuring the Malondialdehyde (MDA) level in blood (3) Assess the activity of erythrocytes superoxide dismutase (SOD) enzyme (4) Identify the personal and occupational risk factors that may be associated with level of (MDA) detected, activity of (SOD) enzyme and level of (ttMA) in studied groups. Subjects & Methods: A cross sectional study was conducted among 43 male workers exposed to Benzene in 6 petrol stations present in Zagazig City. A control group of 40 male service workers, not exposed to Benzene were selected from the Faculty of Medicine in Zagazig University. All workers were subjected to a structured questionnaire included questions about (Personal and socio-demographic data- Occupational history- Oxidative stress questionnaire) and laboratory investigations to measure Trans,trans-muconic acid, Malondialdehyde and Superoxide Dismutase. Results: Results of this study showed that there is a high statistically significant difference regarding the level of (ttMA) & (MDA) which is higher among exposed compared to control group, while the level of (SOD) is statistically lower among exposed group. There is a high statistical significant difference concerning the level of (MDA) among smokers and non-smokers in exposed group as it is higher among smokers compared to non-smokers. Results also showed that there is statistically significant difference regarding the effect of work duration on the level of (ttMA), (MDA) and (SOD) among exposed group, as levels of (ttMA) & (MDA) increased with increased work duration while (SOD) level decreased with increased work duration. There is also a high statistically significant difference between level of (MDA) and chronic emotional stress among exposed group as (MDA) level increased with the increase of emotional stress. Conclusion: It was clear from this study that refueling procedure is an important source of exposure to benzene for the filling station workers who had higher level of benzene metabolites than control and the study also supports the hypothesis that Benzene and its metabolites induce oxidative stress which may plays a role in benzene-initiated toxicity.
Keywords: Oxidative stress, Antioxidants, Petrol station, Benzene