Occupational bioaerosol exposure in composting plants

Abstract

The worldwide waste treatment industry VEOLIA ENVIRONNEMENT carried out a bibliographical review of the occupational exposure to bioaerosols in composting plants, which is based on a literature survey conducted since 1993 by the French Health and Waste Network. Composting is an aerobic biological waste treatment. Bioaerosol released from composting contains mesophilic and thermophilic microorganisms. Bacteria, fungi, particularly Aspergillus fumigatus, and thermophilic actinomycetes are the most frequent microorganisms detected in the ambient air of composting plants. These microorganisms are known to be allergenic agents. Viruses and parasites have never been investigated in the air of composting plants. Microorganism concentrations in the air vary with the seasons, the type of composting process and the waste composted. Maximum microorganism concentrations (10 3-10 5 cfu/m 3) are detected in the loading area and during waste crushing and windrows turning. Mycotoxins produced by Aspergillus fumigatus or Penicillium that are present in the ambient air of some composting plants are correlated with high concentrations of fungi spores. High concentrations of Gram negative bacteria (10 3 cfu/m 3) (Klebsiella, Proteus, Xanthomonas, Serratia…) have sometimes been detected in the ambient air of composting plants. Endotoxin concentrations in the air range from 0,3 to 5,9 ng/m 3 depending on the season. Mean dust concentrations reached 3,1 mg/m 3 but dust concentration peaks have been measured during some handlings. Dust, endotoxins and (1-3)-β-D glucan concentrations are moderately correlated in one study. Therefore it could be interesting to quantify dust concentration as an indicator of bioaerosols exposure. Considering the variability of exposure factors, additional exposure studies would be helpful to better assess the biological risk regarding specific processes and work organisation in order to optimize preventive measures towards bioaerosols occupational exposure in composting plants.

Organically grown cannabis (Cannabis sativa L.) plants contain a diverse range of culturable epiphytic and endophytic fungi in inflorescences and stem tissues

“…In mushroom cultivation facilities that utilize varying sources of composts as a substrate, the occurrence of high numbers of airborne fungal spores has raised concerns over the potential for inhalation by workers and triggering asthma and other respiratory problems (Tanaka et al 2001;Ampere et al 2012). Similar findings were reported in compost manufacturing facilities, where human exposure to airborne spores was reported to be of potential concern (Forestier et al 2008;Wery 2014). In these environments, aerosols contained a range of fungi, including species of Aspergillus, Penicillium, Cladosporium, Alternaria, Mucor, Rhizopus, and Conidiobolus, among others (Wery 2014).…”