Measurement of benzene and other volatile organic compounds: implications for its inhalation health risk associated with the workers at a fuel station in Delhi

Abstract

Exposure to benzene and other volatile organic compounds (VOCs) like toluene, ethylbenzene, o-, m-, and p-xylene (BTEX) at a fuel station is hazardous for the workers. This study aims to estimate the health risk for worker due to the exposure of BTEX after implementation of vapour recovery system (VRS) at fuel stations. Air samples were collected using low-flow sampling pump as per NIOSH method by using Tenax (sorbent) tubes and charcoal (sorbent) tubes. Target compounds were extracted using acetone and analysed by gas chromatography equipped with flame ionization detector (FID). The cancer risk (CR) and hazard quotient (HQ) were estimated to assess the cancer and non-cancer risk following the United States of Environmental Protection Agency (USEPA) updated methodology. The average concentration of VOCs at the fuel station is found in the order toluene > benzene > xylene > ethylbenzene which may be attributed to the composition of fuel (petrol/diesel). Benzene is the most carcinogenic among BTEX, which is found to be 217 ± 9 µg m⁻³ and 158 ± 9 µg m⁻³ in the month of November 2021 using Tenax sorbent and charcoal sorbent tubes, respectively. The high concentration observed using Tenax sorbent may be attributed to its high adsorption efficacy than charcoal due to larger surface area and porosity. The 7-month average CR value of benzene was 9 × 10⁻⁴ using Tenax sorbent and exceeds the acceptable range of 1 × 10⁻⁶. CR of benzene exposure at the fuel station under study is also compared with that of outdoor ambient air exposure. Benzene measurement data for the same duration was taken from nearby online monitoring station of Delhi Pollution Control Committee (DPCC) PUSA to estimate CR value for outdoor ambient air benzene exposure. The value of HQ for benzene was observed > 1 which exceeds the acceptable value and hence increased the non-cancer health risk also. Hazard index (HI) value for BTEX is also greater than 1 which indicates adverse health effects of benzene and other VOCs at the fuel station. The high CR and HQ values for benzene are a matter of concern for fuel station workers.