Assessment of Odorous Compounds and Benzene, Toluene, Ethylbenzene, and Xylene Health Risk in the Vicinity of a Mixed Waste Landfill

Background: Landfilling causes significant environmental pollution by contaminating the soil, water, and air.Although benzene, toluene, ethylbenzene, and xylene (BTEX) exposure in urban and industrial areas is well-documented, studies on BTEX levels and associated health risks in landfill environments remain limited.Objectives: This study assessed air pollutants originating from unmanaged landfills and leachate in nearby residential areas to establish baseline data for landfill management and environmental policy.Methods: BTEX sampling was conducted during three seasons: winter (February 28~March 2), spring (May 27~28), and summer (September 10~11).A total of 18 samples were collected at each site during the day (14:00~16:00) and at night (20:00~22:00).Odor compounds were sampled only during spring and summer.Hazard quotients (HQ) were calculated for BTEX and odor compounds, while cancer risks (CR) were assessed for benzene and ethylbenzene.To assess pollutant variability from rainfall, cumulative rainfall in the study area was analyzed using Korea Meteorological Administration data.Results: Although average BTEX concentrations showed no substantial differences between the study and control areas, maximum concentrations were generally higher in the study area.Hazard quotients (HQs) for BTEX were below 1, indicating a low non-carcinogenic risk.However, the excess lifetime cancer risks (ELCRs) for benzene and ethylbenzene exceeded the threshold of 1.0E-06 under worst-case scenarios, suggesting a potential cancer risk from long-term exposure.Among odor compounds, ammonia (HQ=25.04)and hydrogen sulfide (HQ=20.88)exceeded regulatory limits, suggesting a high likelihood of odor-related discomfort and potential health effects. Conclusions:In the worst-case scenarios, the estimated ELCRs for benzene and ethylbenzene were 13 and 28 cases per million, respectively.Odor compound levels exceeded regulatory limits in both landfill and residential areas, indicating potential health risks and the necessity for mitigation.