Investigating the respiratory and systemic effects of exposure to BTEX among municipal solid waste workers

Abstract

Workers at municipal solid waste (MSW) facilities may be exposed to a range of volatile organic compounds (VOCs). This study aimed to evaluate the potential systemic and respiratory effects, as well as to conduct cancer and non-cancer health risk assessments, associated with exposure to an important group of VOCs—Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX)—among MSW workers. For this purpose, 48 air samples were collected from an MSW facility (36 samples from the landfill and 12 samples from the transfer station) and from a green space serving as the control area (n = 6), located in Hamedan, in the west of Iran, during the spring and summer of 2019. Additionally, 60 individuals (30 in the exposure group and 30 in the control group) underwent testing for inflammatory markers, blood factors, and respiratory function. The highest levels of all BTEX compounds were detected at the transfer station, while the lowest concentrations were found at the green space. The mean concentrations of total BTEX compounds were 127 μg/m³, 42 μg/m³, and 4 μg/m³ for air samples collected from the transfer station, the landfill, and the green space, respectively, with Toluene being the dominant pollutant at all sampling sites. While all BTEX compound concentrations remained below the Reference Concentration (RfC) and Threshold Limit Value (TLV), high lifetime cancer risks (LCRs) for Benzene and Ethylbenzene were observed at certain sampling locations, particularly at the transfer station and the active zone of landfill, with LCR values exceeding acceptable thresholds. Biological monitoring of workers indicated that working at sites with higher concentrations of BTEX adversely impacted blood biomarkers and respiratory function. This emphasizes the need for more effective protective strategies to minimize exposure and address associated occupational hazards.