The assessment of airborne bacterial contamination in three composting plants revealed site-related biological hazard and seasonal variations

Abstract

Aims: The purpose of this study was to evaluate the degree of bacterial contamination generated by three Italian composting plants (1, 2 and 3) in two different seasons and to assess the health risk for the employees. Methods and Results: Aerosols samples were collected with an agar impact sampler. Several plant sites and external upwind and downwind controls were examined. Total colony‐forming counts of mesophilic and thermophilic bacteria, actinomycetes and streptomycetes, Gram‐negatives, coliforms and sulfite‐reducers were determined. Selective media were used in order to isolate pathogenic bacteria. The levels of total mesophilic and thermophilic micro‐organisms ranged between 33 and >40 000 CFU m−3 in plant 1, 39 and 18 700 CFU m−3 in plant 2 and 261 and 6278 CFU m−3 in plant 3. Strains of Escherichia coli, Staphylococcus aureus and Clostridium perfringens were also found. Conclusions: The plants monitored in this study have proved to be sources of aerosolized bacteria. The activities involving mechanical movement of the composting mass and the indoor activities were of greatest potential risk. In all the studied plants, a statistically significant dependence was found between the bacterial contamination and the season for some or almost all the analysed parameters, but a clear seasonal trend could not be observed. Significance and Impact of the Study: This study provides broad evidence of bacterial aerosol dispersion and site‐related biological hazards that may be useful to the regional government to implement regulations on worker safety in composting plants.

Concentrations and Diversity of Microbes from Four Local Bioaerosol Emission Sources in Finland

“…These activities may be significant sources of potentially pathogenic microorganisms to the surrounding environment. [9][10][11] For example, Aspergillus fumigatus and actinomycetes have been shown to be present in emissions from composts. 3,12,13 Biological waste treatment processes may be located in the vicinity of residential areas, and because of the potential spread of microorganisms of fecal origin, they may be a cause of concern to nearby residents.…”

Characteristic and Concentration Distribution of Culturable Airborne Bacteria in Residential Environments in Beijing, China

“…Bioaerosol, defined as an airborne particle that is living or originate from living organisms, is one of the most important indoor air contaminants, and they contribute to about 5-34% of indoor air pollution (Srikanth et al, 2008). Exposure to bioaerosols might be responsible for a large part of respiratory diseases (such as rhinitis, asthma, and pneumonia) and other adverse health effects such as infections, hypersensitivity pneumonitis and toxic reaction (Gorny et al, 2002;Fracchia et al, 2006). As to airborne bacteria, they are important and abundant living component of atmospheric bioaerosols (Jaenicke, 2005).…”

Assessment of airborne bacteria and fungi in an indoor and outdoor environment

“…Exposure to bio-aerosols, containing airborne microorganisms and their by-products, can result in respiratory disorders and other adverse health effects such as infections, hypersensitivity pneumonitis and toxic reactions (Gorny et al, 2002;Fracchia et al, 2006). Fungi are common in indoor and outdoor environments and nearly 10 % of people worldwide have fungal allergy (Pasanen et al, 1996).…”