Introduction: Exposure to Volatile Organic Compounds (VOCs) has been a major concern for the scientific community in recent decades. These compounds are emitted as gases from certain solids or liquids and include a variety of chemicals, some of which may have short- and long-term adverse health effects. VOCs are emitted by a wide array of products numbering in the thousands, including paints, varnishes, wax, many cleaning, disinfecting, cosmetic, degreasing, and hobby products, as well as fuels. The chemical diversity of VOCs can cause both cancerous and non-cancerous health effects. Among the numerous VOCs, Benzene, Toluene, Ethylbenzene, and Xylene (collectively known as BTEX) are the major contributors, which have adverse effects such as headaches, eye irritation, weakness, fatigue, insomnia, respiratory problems, and carcinogenicity. The Environmental Protection Agency (EPA) has identified 189 air pollutants, of which97 are VOCs. Benzene, in particular, is a well-known carcinogen. The International Agency for Research on Cancer (IARC) has classified Benzene as a Group 1 carcinogen due to its strong link to leukemia. Long-term exposure to high levels of benzene in the air can cause leukemia, particularly acute myeloid leukemia. Exposure to VOCs, especially Benzene, can occur through inhalation, ingestion, and skin contact. Therefore, this study evaluates the cancer risk of benzene in the South Pars region, a major hub for natural gas extraction and petrochemical industries in Iran.
Materials and Methods: Data were collected using passive sampling methods from January 2020 to January 2021 across ten sampling stations located in both industrial and residential zones. Samples were analyzed using GC (Gas Chromatography), and the maximum, minimum, and average concentrations were calculated over the one-year period. Results showed that the average annual concentration of benzene fluctuated between 1.4 µg/m³ (at sampling satation NO.8) and 26.3 µg/m³ (at sampling satation NO. 2). This average annual concentration served as the basis for cancer risk assessment. According to the locations of the sampling stations, which are located in three industrial zones and seven in residential areas, including two near schools, exposure assumptions such as daily exposure time (ET), exposure frequency (EF), exposure duration (ED), and average lifespan were considered for seven population groups to calculate cancer risk.
Results: Findings showed that cancer risk from benzene is higher for non-resident industrial workers compared to resident workers. Moreover, urban-official areas posed significantly higher risks for permanent residents and industrial workers living in those areas than for people who only commuted there during working hours. Despite the maximum Benzene concentrations being recorded at industrial sampling stations, the cancer risk in residential-urban areas is high due to longer exposure time (ET), exposure frequency (EF), and exposure duration (ED) for the native population compared to satellite workers, even though the levels are within the Department of Environment (DOE) of Iran's limits. The maximum level of Benzene cancer risk in the urban area for native people is 23 x 10⁻⁶, for non-resident industrial workers in the industrial zone is 22 x 10⁻⁶, and for industrial employees who live in urban areas is 15.6 x 10⁻⁶.
Discussion: Therefore, because of the high level of Benzene cancer risk for industrial employees, it is necessary to reduce Benzene emissions from industries located around Sampling Station No. 2 immediately and effectively. Moreover, it is essential to implement an action plan for the residential-urban population, similar to the specific monitoring plan for staff health in the industrial units.