Health risk assessment of heavy metals, BTEX and polycyclic aromatic hydrocarbons (PAHs) in the workplace in a secondary oil re-refining factory

Document Type : Original Article


1 Department of Environmental Engineering, Tehran West Branch, Islamic Azad University, Tehran, Iran

2 Environment and Energy Department, Science and Research Branch, Islamic Azad University, Tehran, Iran

3 Department of Environmental Engineering, Science and Research Campus, Islamic Azad University, Ahvaz, Iran

4 School of Environment, College of Engineering, University of Tehran, Tehran, Iran

5 Department of Earth and Environmental Science, Irving K. Barber School of Arts and Sciences, The University of British Columbia, Okanagan Campus, 1177 Research Road, Kelowna, BC, VIV 1V7, Canada

6 Department of Environmental Pollution, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran


The present study aimed to evaluate the health risk of heavy metals (iron, zinc, cadmium, arsenic, nickel, lead, and mercury), benzene, toluene, ethylbenzene and xylene (BTEX), and polycyclic aromatic hydrocarbons (PAHs) in the workplace in a secondary oil re-refining factory. In this descriptive, cross-sectional study, samples were collected and analyzed using the NIOSH 1501 method at eight sampling points with determined concentrations of BTEX, 16Ʃ PAHs, and heavy metals. The concentration of each pollutant was evaluated based on the type of workers (packaging/filtration). The risk assessment of the contaminants was carried out using the RAIS software, and the risk of non-carcinogenic compounds was estimated based on the reference respiratory concentration (mg/m3). The results showed that the lifetime cancer risk index (LCR) cumulative risk of the heavy metals was within the definitive risk range at all the sampling points. The highest carcinogenic risk of LCR belonged to arsenic at sampling point H (filtration chamber), and the highest cumulative carcinogenic risk of the total contaminants in the environmental sampling points belonged to sampling point H. At all the sampling points, the LCR carcinogenic risk accumulation for the hydrocarbon compounds was within the definitive range. The maximum cumulative lifetime cancer risk for the hydrocarbon compounds was evaluated in filtration (point B), and the most hazardous carcinogens were arsenic, benzo(a)pyrene, and naphthalene. The proposed risk assessment method was observed to be comprehensive, and its results could be used for corrective and controlling measures and the prioritization of risk reduction resources.


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