Comparative personal exposures to organic dusts and endotoxin

The aims of the study were to provide valid comparative data for personal e xposures to dust and endotoxins for different occupations and to calculate comparative data for the contamination of organic dusts with endotoxin. Nine different occupational settings were studied, drawn from the textile, agricultural and animal handling industries. Samples were collected by pers onal sampling techniques, using the Institute of Occupational Medicine (IOM ) sampling head, glass fibre filters and rechargeable sampling pumps. The d ust exposures were calculated by gravimetric analysis and using the calcula ted volume of air sampled were expressed as mg/m(3). Endotoxin exposures we re measured using a simple water extraction from the collected dusts, follo wed by a quantitative turbidimetric assay. Results were expressed as ng/m(3 ), using the calculated volume of air sampled. In addition, the levels of t he contamination of dusts with endotoxin for individual industries were exp ressed as ng/mg of collected dust. Two hundred and fifty nine samples, collected from 9 different industries a nd across 36 different sites were analysed. This represented a sampling rat e of 25% for the total work force. The average sampling time was 4.62 h. Fo r all the dusts collected; a significant correlation between the collected dust and endotoxin was seen (r = 0.7 and p < 0.001). The highest dust expos ures occurred during cleaning activities (grain handling: 72.5 mg/m(3)). Th e individuals exposed to the highest median level of dust and endotoxin wer e the animal handlers (poultry handlers, dust: 11.53 mg/m(3), endotoxin: 71 ,995 ng/m(3)). Weaving and mushroom cultivation had the lowest exposures fo r dust and endotoxins. The mostly highly contaminated dusts (median values expressed as ng of endotoxin per mg of collected dust) were found in the an imal handling (poultry: 1,030 ng/mg, swine: 152 ng/mg) and cotton spinning (522 ng/mg) industries; Processing of cotton and wool fibres was found to r educe the levels of contamination of dusts with endotoxin. In the study, valid comparative data for personal exposures to organic dust s and endotoxins have been presented. The highest exposures were found amon gst animal handlers and during cleaning activities. The results highlight t hat dust exposures are greater in a number of industries than the set expos ure standards. In addition, endotoxin exposures are found to be greater tha n levels at which harmful effects have been demonstrated. (C) 1999 British Occupational Hygiene Society. Published by Elsevier Science Ltd. All rights reserved.