Characterization and Health Risk Assessment of Volatile Organic Compounds in Gas Service Station Workers

Gas service station workers who work near volatile organic compounds (VOCs) sources, such as gasoline vapor emissions, and motor vehicle exhausts, may be exposed to highly elevated VOCs levels. This study investigates air samples from gas service stations in Thailand to evaluate the health risks following inhalation exposure. Personal air samplings were obtained at nine gas service stations in Chonburi, Thailand from October to December 2007. The concentrations of benzene, toluene, ethylbenzene, xylenes, and hexane in the air from the workplaces were significantly higher than in a control group of office workers (p<0.05). However, all VOCs in these air samples were lower than TWA limit of Thailand and the OSHA standard. Samples of urine, collected after 8-h work periods which were analyzed for VOCs metabolites, including t,t muconic acid, hippuric acid, mandelic acid and m-hippuric acid, demonstrate that the average levels of metabolites in gas service station workers and in controls were close, except for t,t muconic acid of gas service station workers which displayed higher levels than the in the controls. The lifetime cancer and noncancer risks for the workers exposed to VOCs were also assessed. Results show that all nine gas service stations in this study had a elevated lifetime cancer risk ranging from 53 to 630 per million, thus exceeding the “normal ” risk of 1 per million. For noncancer risks, the levels in all gas stations ranged between 0.03 and 0.4, which is well below the reference hazard level of 1.0. Benzene may the most important cause of both cancer and noncancer risk followed by 1,3 butadiene