Occupational exposure of petroleum depot workers to BTEX compounds

Benzene, toluene, ethylbenzene and xylene [BTEX] are the most important toxic volatile compounds in the air and could be easily absorbed through the respiratory tract. In recent years, the risk of exposure to BTEX compounds, especially benzene as a carcinogen, has been considered in petroleum depot stations. To assess the occupational exposure of petroleum depot workers in Iran to BETX compounds. After completing a questionnaire and assessing occupational exposure to BETX compounds, 78 [46 exposed and 32 non-exposed] depot workers were randomly selected to participate in this study. Air sampling and analysis of BTEX was conducted according to the NIOSH method No. 1501. Analysis of urinary hippuric acid, as an indicator of toluene exposure, was carried out according to NIOSH method no. 8300. Personal monitoring of the high exposure group to BTEX compounds was repeated to verify the results obtained in the first phase of the monitoring. Among the 9 operating groups studied, occupational exposure to benzene and toluene was higher in quality control and gasoline loading operators - the median exposure ranged from 0.16 to 1.63 ppm for benzene and 0.2 to 2.72 ppm for toluene. Median exposure of other group members to BTEX compounds was below the detection limit of analytical method [0.07, 0.06, 0.05, and 0.05 ppm, respectively]. The level of toluene exposure measured showed correlation with neither post-shift urinary hippuric acid [Spearman's rho = 0.128, p=0.982] nor with the difference between post- and pr-shift urinary hippuric acid [Spearman's rho=0.089, p=0.847] in depot operational workers. Gasoline loading operators are exposed to a relatively high level of benzene

[Assessment of occupational exposure to total dust and crystalline silica in construction workers of metro, Tehran]

Exposure to crystalline silica in the construction workers such as miners and diggers are widespread. Exposure to respirable silica [quartz] can results in silicosis. The goal of this study was to determine the contribution of each workers and component task to total dust and respirable quartz exposure in the tunnel of metro. The assessment of crystalline silica and total dust was performed according to standard procedure [NIOSH 7601]. Both total dust and quartz levels were high. The results of total dust in the digging process [37.63 +/- 0.76 mg/m[3]] were higher than in the cement work [9.88 +/- 0.80 mg/m[3]]. The maximum 8 h time-weight average concentration for quartz was found among the digging workers [0.407 +/- 0.006 mg/m[3]], followed by the barbed workers [0.11 +/- 0.008 mg/m[3]]. It can be concluded that the total dust contains high amounts of crystalline silica and it is responsible for the occupational exposure to quartz in construction workers. Thus, it is to be expected that the construction workers will suffer negative health effects due to exposure to the quartz dust