Pascal Pageau | PubMed Health

PubMed2006

Bioaerosols in peat moss processing plants.

Peat moss is organic matter colonized by large numbers of microorganisms. Storage prior to its processing may result in massive microbial growth. These biological contaminants can become airborne during processing. Our goals were (a) to evaluate concentrations of bioaerosols (inhalable dust, molds, bacteria) in peat moss processing plants that used dust removing systems, and (b) to evaluate the presence of these microorganisms in peat moss. Fourteen plants from Eastern Canada were visited; 3 plants operated all year (all-year mixing plants), and 11 plants functioned only during summer months (seasonal). Air samples were taken throughout the day at different work sites using IOM cassettes for inhalable dust and All-Glass Impinger-30 samplers and Andersen six-stage impactors for microorganisms. Samples of nonprocessed and bagged peat moss (solid material) were also taken and analyzed. A total of 25 work sites for air sampling and 33 solid material samples were analyzed. Air samples contained up to 441.7 mg/m3 of inhalable dust and up to 1.0 x 10(8) CFU/m3 mesophilic molds and 3.3 x 10(5) CFU/m3 bacteria. Seasonal plants were more contaminated with molds and dust than all-year mixing plants. Sieving sites were the most highly contaminated work sites. Airborne dust concentration was significantly correlated with molds and bacteria. Up to 3.8 x 10(7) CFU/g (dry weight) and 4.8 x 10(7) CFU/g (dry weight) molds and bacteria, respectively, were found in the solid material samples. Airborne contaminants did not correlate with solid material content. Despite the use of dust removing systems, peat moss processing plants contain very large amounts of microbially contaminated bioaerosols that do not correlate with the quality of the processed peat. Efficiency of dust removing systems could influence the contamination levels.

Air Pollutants, Occupational↗

PubMed2006

Sensitization to airborne molds and its health effects in peat moss processing plant workers.

The goal of this study was to evaluate the incidence of sensitization to the major molds found in peat dust in workers exposed to stored peat moss and the health impact of this sensitization. Air samples from each plant were obtained to measure the levels of airborne molds, bacteria, and dust. There were 189 workers from 14 peat moss processing plants (3 all-year mixing plants and 11 seasonal plants) recruited for the study. The subjects completed a symptoms questionnaire, underwent spirometric measurements and skin-prick tests, and gave venous blood samples. Blood samples from 43 nonexposed control subjects were also taken. A similar percentage of smokers from both plant types was observed. Twenty-eight percent of the workers tested had a positive serum reaction to at least one of the tested molds. The percentage of positive workers varied from plant to plant, going from none in 4 plants to 14 out of 21 for 1 plant. This variability was not correlated with the airborne levels of molds. FEV tended to be lower in the workers with positive antibodies compared with seronegative workers. IgG positive frequency was higher for those workers employed in the all-year plants, and workers from those plants had lower FEV/FVC than seasonal plant workers. Seasonal plants were more contaminated with molds than all-year mixing plants, suggesting that the duration of exposure may trigger more sensitization than the level of exposure. We conclude that there is a high incidence of mold sensitization in peat moss factory workers and that this sensitization may have a negative respiratory health impact.

Adult↗