Exposure to bioaerosols for wastewater treatment plant workers: Prioritization of the areas and tasks involving the greatest exposure, and prevention

Delphine Forestier; Élise Lecornet; Luc Mosqueron; Lucie Lambolez

doi:10.1684/ers.2012.0519



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Exposure to bioaerosols for wastewater treatment plant workers: Prioritization of the areas and tasks involving the greatest exposure, and prevention
Environnement, Risques & Santé. Volume 11, Number 2, 137-48, Mars-Avril 2012, Articles originaux
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Author(s) : Delphine Forestier, Élise Lecornet, Luc Mosqueron, Lucie Lambolez
Summary : Despite the lack of documentation, the biological risks related to bioaerosols in the wastewater treatment sector remain a fundamental issue. To optimise prevention of occupational risks, we conducted this study of exposure to bioaerosols among wastewater treatment plant workers. The concentrations in the air of different microorganisms and biological agents (culturable bacteria and fungi, Gram-negative bacteria, endotoxins and Legionella) were measured near the main treatment equipment at 5 different plants. Workers completed a descriptive questionnaire about their tasks and the time spent in each area. We used these results to construct a prioritization matrix of the areas and tasks that contribute most to exposure, by crossing the bioaerosol levels measured with the data collected on the workers’ activities. Pre-treatment equipment (either indoors or in confined areas), sludge dewatering equipment, and the tasks involving hosing down (with or without high pressure) were given top priority in terms of bioaerosol exposure. Recommendations to prevent exposure were defined, focussing especially on collective prevention, including pollutant capture at the source (selection of processes resulting in lower emissions, confinement, and equipment isolation with panes of glass or plastic curtains), maintenance of ventilation systems, and work organization to prevent workers from spending long periods in the areas where the highest concentrations are measured. When exposure is impossible to avoid in the priority areas, use of FFP2 masks is recommended. For hosing-down operations, it is recommended that workers systematically wear a mask, gloves, goggles and an overall.
Keywords : air microbiology, Legionella, occupational exposure, prevention, wastewater