Occupational exposure of diesel station workers to BTEX compounds at a bus depot

Abstract

Diesel fuel is known to emit pollutants that have a negative impact on environmental and human health. In developing countries like South Africa, attendants are employed to pump fuel for customers at service stations. Attendants refuel vehicles with various octane unleaded fuel, lead-replacement petrol and diesel fuel, on a daily basis. Attendants are at risk to adverse health effects associated with the inhalation of volatile organic compounds released from these fuels. The pollutants released include benzene, toluene, ethylbenzene and xylenes (BTEX), which are significant due to their high level of toxicity. In this study, a risk assessment of BTEX was conducted at a diesel service station for public buses. Using Radiello passive samplers, it was found that benzene concentrations were above recommended international standards. Due to poor ventilation and high exposure duration, the average benzene concentration over the sampling campaign exceeded the US Environmental Protection Agency's chronic inhalation exposure reference concentration. Lifetime cancer risk estimation showed that on average there is a 3.78 × 10-4 cancer risk, corresponding to an average chronic daily intake of 1.38 × 10-3 mg/kg/day of benzene exposure. Additionally, there were incidences where individuals were at potential hazard risk of benzene and toluene that may pose non-carcinogenic effects to employees.

Figure 1

Radiello passive sampler positions in the (a) fuel bay and (b) workshop. Passive samplers were positioned equidistant as possible, at 2 m heights. (Overhead roofs and front walls have been made transparent for viewing purposes. Offices are displayed as white boxes). The fuel bay is adjacent to the workshop at the bus depot.

Figure 2

Cancer risk and hazard quotient (combined benzene, toluene and xylene hazard quotients) as compared to number of years employed.