摘要：Exposing to the high-level of BTXs concentration can occur in the oil-dependent industries and may cause considerable adverse impacts on the health of employees. The main objective of the present study firstly is determining the exposure of petrochemical and oil depot workers to benzene, toluene, ortho and methyl xylenes, and p-xylene (BTXs), and secondly is estimating the lifetime cancer risk (LCR) and non-carcinogenic risk using the hazard quotient (HQ). This cross-sectional study is conducted on 85 workers at petrochemical (34 subjects) and oil depot (51 subjects) industries of Iran in 2016. In order to determine the exposure concentrations of BTXs, through inhaling way, individual sampling was carried out according to the NIOSH 1501 method. Then, estimating LCR of benzene, and non-carcinogenic risk of benzene, toluene, ortho and methyl xylenes, and p-xylene, using the HQ, has been conducted regards to criteria recommended by USEPA. The mean exposure concentration of benzene among the oil depot workers was higher than the petrochemical workers, but this difference was not statistically significant (P = 0.162). The mean exposure concentration of benzene in the oil depot workers (2.1 ± 2.53 mg/m3) was higher than the occupational exposure limits provided by the American conference of governmental industrial hygienists (ACGIH_TLV = 1.67 mg/m3). The mean concentration of toluene in the exposed workers of the oil depot (46.81 ± 22.43 mg/m3) was higher than the exposed workers of petrochemical (41.83 ± 30.06 mg/m3), but this difference was not statistically significant (P = 0.412). The results of carcinogenic and non-carcinogenic risk assessment revealed high-risk exposure level in the both investigated groups. The mean LCR of benzene in the oil depot workers was higher than the petrochemical workers (1.681E-3 and 1.163E-3, for the oil depot and petrochemical, respectively). The LCR of benzene and HQ of BTXs in the both investigated groups were higher than the reference values. In order to reduce occupational exposure to BTXs in the investigated oil depot and petrochemical, control measures should be taken in the future, as soon as possible.
