Bioaerosol Exposure and Health Risk Assessment at a Municipal Material Recovery Facility in Arak, Iran

Introduction: Municipal solid waste (MSW) sorting facilities are sources of airborne biological contaminants. Occupational exposure to bioaerosols, including bacteria and fungi, poses potential health risks for waste workers, especially in poorly ventilated, high-activity areas. This study aimed to assess airborne concentrations of bacteria and fungi across key operational areas of an MSW sorting facility and to evaluate the associated non-carcinogenic health risks using a quantitative health risk assessment (HRA) model. Methods: Between April and May 2024, air samples were collected from four indoor sampling sites and one outdoor control site using impaction methods. Concentrations of culturable airborne bacteria and fungi were determined and compared with international guideline values. A US EPA-based HRA model was employed to estimate chronic daily intake (CDI) and hazard quotient (HQ) values. Results: Bacterial concentrations ranged from 16 to 4128 CFU/m3, and fungal concentrations from 22 to 1120 CFU/m3. The manual sorting station exhibited the highest levels of bioaerosols. Calculated HQs for bacterial exposure exceeded the acceptable limit (HQ > 1.0) at multiple sites, particularly at the manual sorting line (HQ = 2.87), indicating potential non-carcinogenic health effects. Fungal exposure remained within acceptable limits. Indoor-to-outdoor (I/O) ratios confirmed significant indoor sources of bioaerosols. Conclusion: This study emphasizes the importance of improved ventilation, personal protective equipment, and bioaerosol monitoring. Also, utilizing health risk assessments to environmental analysis is a key strategy for minimizing health risks associated with exposure in the waste management industry.