Airborne fungal pollution at waste application facilities

Abstract

This study aims to evaluate airborne mesophilic and thermophilic fungal concentrations and types at a wastewater treatment plant (WWTP) and a biosolid landfill, in Egypt. Air samples were collected at 200 m upwind, and on-site and 300 m downwind by using liquid impinger sampler, calibrated to draw 12.5 L/min, for 20 min. Fungal concentrations ranged between 427–7 280 CFU/m3 for mesophilic and 0–3,968 CFU/m3 for thermophilic fungi. The concentrations exceeded the suggested occupational exposure limit value of 500 CFU/m3. Aspergillus fumigatus represented ~34.9–55 % and 60.4–71.4 % of the total mesophilic and thermophilic fungi, respectively. Significant differences were observed between the upwind and downwind concentrations at both waste facilities, and between on-site and downwind fungal concentrations (P ≤ 0.01) at the landfill, and only for thermophilic fungal concentrations at the WWTP (P ≤ 0.05). Higher fungal diversity was found at the landfill site. A. terreus, A. ochraceus, Acremonium, Geotrichum, Aureobasidium, Sepedomium, and Trichophyton were only detected at the landfill sites. Fungal concentrations positively correlated with temperature. Higher concentrations were observed at wind speed 3 m/s at the landfill. Wind speed positively affected concentrations at the landfill. The regression model showed that relative humidity was a significant determinant of fungal concentrations 300 m downwind distances. Waste application facilities increase fungal concentrations on-site which may consequently deteriorate air quality in the nearby areas.