Benzene and toluene exposure in relation to their health effects among sky-train station guards in Bangkok, Thailand

Abstract

Background: Benzene (B) and toluene (T), contributed to short-term and long-term health hazards, are naturally emitted into the atmosphere through exhausts of vehicles. This cross-sectional study aimed to examine BT exposure concentrations and to investigate BT exposure health effects among sky train station security guards in Bangkok.

Methods: Charcoal Glass tube connected to active personal pump was used to collect benzene and toluene concentration during 8 working hours from 40 sky train security guards; 20 guards working at platform level and 20 guards working at ticket level.  Post shift urinary metabolites, trans, trans- muconic acid (t,t-MA) and hippuric acid (HA) were accessed. Questionnaires were collected from security guards at the end of work shift. Multiple logistic regression performed to find an association between BT exposure and their health effects. 

Results: The median concentration of benzene and toluene were 0.21 and 242.40 µg/m³. Statistical difference between ticket and platform level was not found. Post-shift urine t,t-MA and HA, were not correlated with their parent compounds. Benzene exposure was positively associated with fatigue. On contrary, an association between toluene exposure and health effects was not found after adjusted possible confounders.

Conclusion: Sky train security guards were exposed to low concentrations of BT, which could partially explain their low levels of adverse health effects.