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Title: Evaluation of the deposition, translocation and pathological response of brake dust with and without added chrysotile in comparison to crocidolite asbestos following short-term inhalation: Interim results

Chrysotile has been frequently used in the past in manufacturing brakes and continues to be used in brakes in many countries. This study was designed to provide an understanding of the biokinetics and potential toxicology following inhalation of brake dust following short term exposure in rats. The deposition, translocation and pathological response of brake dust derived from brake pads manufactured with chrysotile were evaluated in comparison to the amphibole, crocidolite asbestos. Rats were exposed by inhalation 6 h/day for 5 days to either brake dust obtained by sanding of brake-drums manufactured with chrysotile, a mixture of chrysotile and the brake dust or crocidolite asbestos. No significant pathological response was observed at any time point in either the brake dust or chrysotile/brake dust exposure groups. The long chrysotile fibers (> 20 μm) cleared quickly with T{sub 1/2} estimated as 30 and 33 days, respectively in the brake dust and the chrysotile/brake dust exposure groups. In contrast, the long crocidolite fibers had a T{sub 1/2} > 1000 days and initiated a rapid inflammatory response in the lung following exposure resulting in a 5-fold increase in fibrotic response within 91 days. These results provide support that brake dust derived from chrysotile containing brakemore » drums would not initiate a pathological response in the lung following short term inhalation. - Highlights: • We evaluated brake dust w/wo added chrysotile in comparison to crocidolite asbestos. • Persistence, translocation, pathological response in the lung and pleural cavity. • Chrysotile cleared rapidly from the lung while the crocidolite asbestos persisted. • No significant pathology observed at any time point in the brake-dust groups. • Crocidolite produced pathological response - Wagner 4 interstitial fibrosis by 32d.« less
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [4] ;  [5] ;  [6]
  1. Consultant in Toxicology, 1208 Geneva (Switzerland)
  2. Rogers Imaging, Needham, MA 02494 (United States)
  3. GSA Gesellschaft für Schadstoffanalytik mbH, D-40882 Ratingen (Germany)
  4. Fraunhofer Institute for Toxicology and Experimental Medicine, D-30625 Hannover (Germany)
  5. National Institute for Occupational Health, National Health Laboratory Service (South Africa)
  6. (South Africa)
Publication Date:
OSTI Identifier:
22439687
Resource Type:
Journal Article
Resource Relation:
Journal Name: Toxicology and Applied Pharmacology; Journal Volume: 276; Journal Issue: 1; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; AMPHIBOLE; ASBESTOS; COMPARATIVE EVALUATIONS; DEPOSITION; DUSTS; FIBERS; FIBROSIS; INFLAMMATION; INHALATION; LUNGS; PATHOLOGY; PLEURA; RATS