Introduction
Composting, otherwise known as green waste recycling, is a growing industrial sector. Whilst the environmental benefits of recycling activities are well-established, there is currently only a limited understanding of the potential adverse health effects of exposure to occupational hazards such as bioaerosols. It is thought that bioaerosol exposure may induce or exacerbate respiratory illness, but little is known about which components are responsible or which workers are most vulnerable.
Methods
A cross-sectional study examining the prevalence of respiratory symptoms in the UK industrial composting workforce was undertaken. Exposure studies were conducted at one indoor and one outdoor site to examine total microbial and fungal counts, as well as thermophilic bacteria and fungi present during agitative composting activities. A health questionnaire was subsequently administered to a volunteer sample of compost workers across six companies, who were also tested by skin prick test and blood for sensitisation to bioaerosol components and common aeroallergens. The questionnaire was evaluated using a principal component analysis (PCA).
Results
Exposure measurements confirmed the sites were ones in which workers had bioaerosol exposure consistent with that observed previously in the industry. Workers reported symptoms including rhinitis, conjunctivitis, cough, wheeze and shortness of breath. Workers with more than 10 years in the industry had a higher prevalence of ocular irritation. No differences were seen according to site type (indoor/outdoor), Aspergillus sensitisation status, or whether workers were mono or polysensitised by IgE to any of the aeroallergens tested in the study. The PCA condensed the questionnaire from 46 to 37 items.
Conclusion
The higher prevalence of ocular symptoms in those workers having been in the industry for more than 10 years is of concern for which the implications merit further study. These include the progression to clinical disease affecting the lower airways and wider systemic disease. Findings from this study do not suggest that those workers sensitised to Aspergillus fumigatus or other aeroallergens reported more symptoms, but further inferences are limited by the cross-sectional design.
