Accumulation of microorganisms on work clothes of workers collecting different types of waste – A feasibility study

Abstract

Electrostatic dust cloths have previously been used to study microorganisms in settled dust by placing the cloths horizontally on surfaces (called Electrostatic Dust Collectors, EDC). In this study, we investigate whether the same cloths, henceforth called ‘E-Cloths’, can be used to study accumulation of microorganisms and endotoxin on workers’ clothes. This was studied as current methods have limitations. It was examined for waste collection workers, as their work environment is associated with elevated exposure to microorganisms and endotoxin. Each worker received a kit with a T-shirt with an attached E-Cloth on the front, a instruction letter, and a questionnaire. Workers wore the T-shirts during the next two workdays. Unaffected by waste type collected, it was possible to measure the accumulation of bacteria, fungi, and endotoxin from the work environment on the E-Cloths. Geometric mean concentration of 9 × 106 CFU bacteria/m2, 1 × 107 CFU fungi/m2, and 4 × 104 endotoxin units/m2 were found. In total, 100 different bacterial and 25 fungal species were found. The genus Bacillus (with 18 species) and Brevibacterium aurantiacum were among the dominating bacteria. For fungi, Penicillium brevicompactum, P. commune, Penicillium italicum, and Aspergillus niger were most often found. Importantly, mainly environmental bacteria and fungi had accumulated on the E-Cloths and only few skin-related bacterial species were present, showing that accumulation had happened from the work exposure and not workers’ skin. In conclusion, the T-shirts with an E-Cloth can be used as a self-administered method for measurement of accumulation of microorganisms and endotoxin from the work environment on waste collection workers’ clothes.