Dustiness and bio-aerosol exposure in sorting recyclable paper

Abstract

In Denmark recycling of household waste is a growing industry and recycled paper is the major source for the Danish pulp production. Paper for recycling may come from various sources including households and industry. The paper is collected separately, but the segregation process may not always be efficient and the paper may be high in microbial content. For workers sorting recyclable paper, data are few on personal exposure to bio-aerosols and a comparative study, therefore, was carried out to establish base-line information. Workers sorting clean paper (items of mail) were included for comparison. The data obtained were compared with data from the literature on exposure of waste collectors to bio- aerosols. The potential of recyclable paper to emit dust (dustiness) and micro-organisms was characterized in the laboratory using a rotating drum dustiness tester and mixed household waste was included for comparison. The study indicated that workers sorting recyclable paper were exposed to high levels of bio-aerosols compared to workers sorting clean paper. Workers sorting recyclable paper were exposed to bio-aerosols at similar or higher levels than workers collecting the paper. However, the exposure level was comparable with or lower than the levels seen in workers collecting mixed household waste. For dust and endotoxin the paper sorting workers were exposed to levels below existing or proposed occupational exposure limits (OELs), but for viable micro-organism exposure may exceed proposed OELs. Dustiness of recyclable paper was high in terms of dust and endotoxin compared with mixed household waste. With regard to viable bacteria, dustiness of paper was at the level of mixed household waste. In principle, paper collected for recycling should be low in microbial content leading to a low bio-aerosol exposure for workers handling the paper. However, recyclable paper may be high in microbial dustiness. This finding indicates low standards of separation in households and/or contamination of the collected paper from dirty containers or collection vehicles.