Characterization and Health Risk Assessment of Airborne Fungi in a Semiunderground Municipal Wastewater Treatment Plant

Abstract

Municipal wastewater treatment plants (WWTPs) are recognized as the significant source of fungal aerosols, which pose a significant threat to human health globally. Herein, the occurrences characterization, community structure, and health risk assessment of airborne fungi were investigated from a semiunderground WWTP. The concentrations of culturable fungi emitted into the air from the WWTP ranged from 30.6 to 1431.1 colony forming units (CFU)/m³, with primary and biochemical treatments constituting the principal sources of emission (P < 0.05). Diversity analysis revealed seasonal and facility-dependent fluctuations in culturable fungal communities. Approximately 13.5% of the total airborne fungal genera detected in the WWTP were culturable. Some airborne fungi in the WWTP with relatively low abundance but high cultivability, such as Cladosporium, Trichoderma, Neurospora, Filobasidium, and Hannaella, tended to be overlooked because of their limited presence in airborne environments. We also developed a health risk assessment method for fungi, utilizing seven indicators to characterize the risk posed by fungal pathogens from multiple perspectives, providing a comprehensive evaluation of potential health impacts. The simulated risk values of the air outlet and biochemical treatment exceeded those of other treatment facilities, with median risks of 2.2 × 10² and 1.4 × 10², respectively. Consequently, management strategies should prioritize enhanced controls for fungal aerosols to mitigate the risk of disease transmission.