Exposure, symptoms and airway inflammation among sewage workers.

The purpose of the study was to determine the associations between dust, endotoxins and bacterial exposure, and health effects in sewage workers. Exposure of 19 workers handling dry sludge and 25 other sewage workers was measured. Controls were office workers from compost and sewage plants. Spirometry, acoustic rhinometry and nitric oxide in exhaled air were performed before and after exposure were measured. CRP was measured in blood samples. It was found that workers handling dry sludge were exposed to higher levels of dust and endotoxins than other workers and reported more airway and systemic symptoms than controls. Compared to controls, FEV(1)/FVC was 0.12 lower in workers handling dry sludge and 0.05 lower in other sewage workers. Nose irritation, cough and headache were more prevalent in workers handling dry sludge (ORs 2.3-23), and together with unusual tiredness associated with endotoxins and/or dust, ORs 2.9-34 for-10-fold increases in exposure. Cross-shift decreases of nasal dimensions were larger in workers handling dry sludge than controls and were associated with dust and endotoxin exposure. It was concluded that workers handling dry sludge were higher exposed to endotoxins and dust than other sewage workers and also reported more respiratory and systemic symptoms. Exposure-response relationships were found for nasal dimensions, nose irritation and systemic symptoms.