Inflammatory potential of dust from waste handling facilities measured as IL-8 secretion from lung epithelial cells in vitro

Objectives: Organic dust contains several different components which may ca use pulmonary effects, and many health problems have been associated with t he collection and recycling of organic waste. It is often difficult to obta in a precise measurement of the exposure to each component in dust, and org anic dust samples obtained from different workplaces may vary profoundly in composition. The aim of this study was to evaluate the inflammatory potent ial of dust from different waste handling plants. Furthermore, we set out t o investigate the role of endotoxin in the inflammatory potential of dust. Methods: Dust samples were obtained from four incineration plants, three sa mples from a plant sorting household waste, five paper-sorting plants, two mail centres, four bottle-sorting plants, and two combined paper-sorting an d composting plants. The samples were tested in a bioassay with the lung ep ithelial cell line A549, Cells were stimulated for 24h with dust samples at six concentrations, and subsequently the interleukin 8 (IL-8) secretion in to the growth medium was measured. The initial slope of the dose response c urves was used to calculate the potency factor (PF) of the dust samples, an d correction against positive control samples was used to reduce day-to-day variation. The concentration of endotoxin in the dust samples was measured by the limulus amebocyte lysate (LAL) assay. Results: The inflammatory potential of the dust samples for dust from the p aper- and mail-sorting plants showed a significantly lower PF as compared w ith dust from the plants handling mixed household waste. A significantly lo wer PF for the dust samples from the bottle-sorting plants (excluding one o utlier plant) compared with dust from the plants handling mixed household w aste was also found. No correlation was observed between the PF and the con centration of endotoxin in the samples. Conclusion: The PFs obtained seem to reflect the material handled, with mix ed household waste generating organic dust with the highest inflammatory po tentials. (C) 2000 British Occupational Hygiene Society. Published by Elsev ier Science Ltd. All rights reserved.