Comparison of Benzene Exposure and Health Effect Among Roadside Occupations in Maptaphut Area Rayong Province

Abstract

The comparison/research was aimed to study the relationship of benzene exposure and adverse health effects of people with roadside occupations in the Maptaphut area, Rayong Province, Thailand. The study used three instruments : 1) an interview-questionnaire verified for validity content by three occupational health and safety and toxicology professionals, and a coefficient reliability of Cronbach’s coefficient alpha, which was 0.947, 2) data collected at the benzene-concentration monitoring stations, and 3) high performance liquid chromatography (HPLC), which was used to analyze trans,trans-muconic acid levels, which is a biomarker for high-level benzene exposure. The study group comprised 80 subjects exposed to roadside benzene-gas-station employees, motorcycle-taxi drivers, traffic police and roadside food vendors; 20 office workers served as the comparative non-exposed group. Descriptive statistics, Repeated Measures Analysis of Variance (ANOVA), and One-way ANOVA, were used for data analysis.

The results showed that two thirds of the study subjects were male. The average age was 38.38 10.39 years. The subjects lived near Sukhumvit Road (38%), a major thorough fare. The average working day was 7-8 hours (an average of 46.02 hours per week). They are did not use respiratory personal protective equipment (PPE) at work (73.7%). The subjects had smoked tobacco (17%), while had been exposed to second-hand smoke (57%). The average daily concentration of benzene in the air was 10.93 10.50 ug/m3. The mean concentrations of urinary trans, trans-muconic acid, at end of a working day among the exposed group (gas-station employees, motorcycle-taxi drivers, traffic police and roadside food vendors), were 115.26 142.64, 40.56 52.15, 46.12 93.83, and 32.42 59.31 µmg/g Cr, respectively. The mean concentration among the non-exposed office group was 5.50 22.54 µmg/g Cr. Three comparisons of urinary trans,trans-muconic acid levels revealed significant differences ( < 0.05). The levels found among gas-station employees and motorcycle-taxi drivers were significantly different ( = 0.002 and  = 0.008, respectively). Members of the exposed group reported headache (67.5%) and dizziness (61.2%). It is recommended that people in these occupations wear the correct type of respiratory PPE at work, to reduce occupational exposure to volatile organic compounds (VOCs), and that they should undergo urinary trans,trans-muconic acid level monitoring annually.