Exposure of Workers of Municipal Landfill Site to Bacterial and Fungal Aerosol

Abstract

The present research was aimed at assessing the quality of air in work environment of the municipal landfill site in Toruń. Air samples were collected in the outdoor space (operating landfill cell, technological square), and in indoor space (sorting station, weighing station, social room) using the impaction method. The microbiological air testing included determining the number of airborne mesophilic bacteria and molds. Bacterial strains were identified with appropriate API tests; molds were identified according to their macro and micro characteristics. In outdoor air, the highest average concentration of mesophilic bacteria were recorded at the operating landfill cell (1361 colony forming unit (CFU)/m3). The highest average concentrations of molds were recorded at the technological square (1179 CFU/m3). In indoor air, the highest average concentration of investigated microorganisms (bacteria: 10 707 CFU/m3, molds: 12 471 CFU/m3) were recorded in the sorting facility. The concentration of microorganisms in the outdoor air depended on the season (p < 0.05), but did not depend on the sampling site, while in the indoor air depended on the sampling site (p < 0.05) but did not depend on the season. Bioaerosol emitted in municipal facility was the source of bacterial (Bacillus subtilis, Pseudomonas aeruginosa) and fungal species (Aspergillus fumigatus, Madurella grisea, Penicillium manfferei, Scedosporium apiospermium, Cryptococcus neoformans), posing a health risk for humans. However Gram‐negative bacteria constituted only a small fraction of the isolated microorganisms. The highest risk of exposure to biological agents was determined in the sorting station. The majority of the outdoor air samples were classified as uncontaminated. The results emphasize the need for regular monitoring of microbiological tests in indoor and outdoor air of municipal landfill sites as well as for control strategies in order to protect workers at landfill.