Airborne Contaminants At Waste Treatment Plants

Abstract

Airborne contaminants in Finnish waste treatment plants were studied at two plants using mainly manual sorting and one incineration plant. Air samples were analysed for mesophilic and thermotolerant bacteria, mesophilic fungi, endotoxin, dust and heavy metals (lead, cadmium). The concentrations of mesophilic bacteria in the working air of the waste treatment plants were under 2 × 10⁴ colony forming units (cfu) m^-3 and the concentrations of mesophilic fungi were under 7 × 10⁴ cfu m^-3. There was no seasonal variation in the concentrations of bacteria, but the concentrations of fungi were highest in autumn at the waste incineration plant. The concentrations of microbes recorded with two sampling methods, the Andersen and Nuclepore filter methods, differed but were usually of the same order of magnitude. The identified bacteria did not include any potent pathogens. In manual sorting the level of organic dust reached 38 mg m^-3, whereas the 8-h hygiene limit value for organic dust is 5 mg m^-3 and the 15-min hygiene limit value is 10 mg m^-3. The endotoxin levels were all below 30 ng m^-3 and the concentrations of heavy metals were low.