The assessment of airborne bacterial and fungal contamination emitted by a municipal landfill site in Northern Poland

Airborne bacteria and fungi are important biological components of bioaerosol and play an important role in the conservation environmental. A microbiological study on bioaerosoles was carried out at the Municipal Waste Utilization Plant in Northern Poland and at points located beyond the facility at the distance of 150, 450, 1000 and 1250 m. The highest emission of bioaerosol occurred in the area of the waste landfill site and during compost pile turning. The total number of mesophilic bacteria, filamentous fungi and actinomycetes reached the values up to 104 CFU/m3. Strong air contamination with mannitol-positive and mannitol-negative staphylococci occurred remarkably more frequently in the area of the test facility than in the points beyond it. The number of indicator bacteria of Pseudomonas fluorescens was quite changeable and did not depend on a distance from pollutant emission source. The number of Escherichia coli rods remained at the low level of about 102 CFU/m3, and they were only isolated sporadically in the points beyond the landfill. The highest percentage of bacterial aerosol comprised Gram-positive cocci, and then Gram-positive bacilli. Mycological analyses confirmed the presence in the studied air of fungi with potentially allergic and mycotoxinogenic properties, such as: Aspergillus fumigatus, A. niger, A. terreus, Cladosporium herbarum and the genus Fusarium. The concentration level of microbial bioaerosol several times exceeded the threshold values recommended by the Polish Standards. The factors influenced the concentration of microorganisms in the tested air included the distance of the active landfill, weather conditions and the season.