BENZENE AND TOLUENE EXPOSURE IN RELATION TO THEIR HEALTH EFFECTS AMONG SKY-TRAIN STATION GUARDSIN BANGKOK THAILAND

The problem of air pollution in Bangkok has been exacerbated by increasingly crowded traffic and transportation, the major sources of pollution. As a result, Benzene and Toluene are commonly often emitted into the atmosphere through exhausts of vehicles and they can contribute to both short-term and long-term health hazards. The aim of this study has been narrowed down to examine Benzene and Toluene and health symptoms exposure among 40 sky train security guards of 20 electric sky train stations in Sukhumvit Line. The exposure of Benzene and Toluene was measured during time of work by using Charcoal Glass tube and personal air pump, for 8 hours, from 8 a.m. to 4 p.m. The collection of urine sampling method to determine metabolite of Benzene, t,t-muconic acid and metabolite of Toluene and hippuric acid follows the NIOSH method 8301. Urine was collected after work. The median concentration of Benzene and Toluene were lower than Time Weight Average (TWA), defined by OSHA and NIOSH, at 0.21(± 4.08) and 242.40 (± 17.11) µg/m3. In addition, the average concentration of Benzene urinary metabolites was higher than the BEIs (Biological Exposure Indices) which defined by ACGIH , 1.02 mg /g Cr of t,t-Muconic acid. In contrary, trans,trans Muconic acid, urinary metabolite of Toluene, was not exceeded the BEIs of ACGIH (269.32 mg/g Cr). BEIs of trans,trans-Muconic acid is defined at 500μg /g Cr and BEIs of Hippuric acid is defined at 1.6 g/g Cr. However, Benzene concentration was not positively correlated with concentration of its urinary metabolite, t,t-Muconic acid at 0.295 of p-value. Meanwhile, Toluene concentration was also not correlated with its urinary metabolite, Hippuric acid, in negative direction at p-value > 0.05. According to Benzene exposure and health symptoms association, increasing Benzene exposure was associated with fatigue occurrence (OR = 21.166; 95% CI, 1.297 – 345.494).