ASBESTOS FIBER TYPE AND LENGTH IN LUNGS OF CHRYSOTILE TEXTILE AND PRODUCTION WORKERS: Fibers Longer Than 18 m
Authors: Andrédufresne, Bruce W. Case; McDonald, A.D.; McDonald, J.C.; Sébastien, Patrick
Source: Inhalation Toxicology, Volume 12, Supplement 1 to issue 10, 1 October 2000 , pp. 411-418(8)
Publisher: Informa Healthcare
Abstract:Excess lung cancer risk for a cohort of chrysotile textile plant workers was many times the risk observed in a cohort of chrysotile miners/millers. The latter had greater exposure to chrysotile/tremolite. A previous lung burden study confirmed this excess exposure in miners/millers and showed littledifference in fiber length. Selection of too short a fiber length cut-off (5 mum or more) in the previous study could have masked differences in lung-retained fiber length. In this follow-up, we counted only those intrapulmonary fibers exceeding 18 mum in length. Lung fiber concentration and dimension were assessed by transmission electron microscopy (TEM) and energy-dispersivex-rayspectrometry (EDS) for autopsy samples from 64 textile workers and 43 chrysotile miners and millers. These long fibers were significantly more concentrated in the lungs of chrysotile miners and millers, consistent with their greater exposure. However, when only these longest fibers were compared, there was a somewhat greater mean and median intrapulmonary fiber length for chrysotile textile workers (mean fiber length, all fiber types combined, 25.2 ± 10.2 mum vs. 22.9 ± 6.6 mum in miners/millers, p < .001; medians 21.6 vs. 20, p < .05). Despite their lesser apparent lung cancer risk, chrysotile, tremolite, total amphibole, and total long fiber asbestos concentrations were all highest in the lungs of miners/millers. Twenty-two of 64 textile workers had lung content of crocidolite and/or amosite (32.5% of 508). These amosite/crocidolite fibers were present in the lungs of workers who ceased employment prior to the first use of such fibers recorded in this industry.The results suggest that (1) asbestos fiber length differences cannot explain the difference in lung cancer risk excess and slope between cohorts and (2) the experience of textile workers should not be used to assess risk of lung cancer in miners, cement workers, and friction product workers, regardless of fiber type.
Document Type: Research article
Publication date: 2000-10-01