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(½) 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(½)>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 brake drums would not initiate a pathological response in the lung following short term inhalation.
Consultant in Toxicology, 1208 Geneva, Switzerland. Electronic address: davidb@itox.ch.
David M
DM
Bernstein
Rogers Imaging, Needham, MA 02494, USA. Electronic address: rarogers5@yahoo.com.
Rick
R
Rogers
Rogers Imaging, Needham, MA 02494, USA.
Rosalina
R
Sepulveda
GSA Gesellschaft für Schadstoffanalytik mbH, D-40882 Ratingen, Germany. Electronic address: Peter.Kunzendorf@GSA-Ratingen.de.
Peter
P
Kunzendorf
Fraunhofer Institute for Toxicology and Experimental Medicine, D-30625 Hannover, Germany.
Bernd
B
Bellmann
Fraunhofer Institute for Toxicology and Experimental Medicine, D-30625 Hannover, Germany. Electronic address: Heinrich.ernst@item.fraunhofer.de.
Heinrich
H
Ernst
National Institute for Occupational Health, National Health Laboratory Service, South Africa; Department of Biomedical Technology, Faculty of Health Sciences, University of Johannesburg, South Africa. Electronic address: jim.phillips@nioh.nhls.ac.za.
James I
JI
Phillips
D000818:Animals; D017638:Asbestos, Crocidolite / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics / Q000633:toxicity; D017632:Asbestos, Serpentine / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics / Q000633:toxicity*; D001195:Asbestosis / Q000276:immunology / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D055598:Chemical Phenomena; D004195:Disease Models, Animal; D004391:Dust / Q000032:analysis; D006207:Half-Life; D007221:Industry; D019570:Inhalation Exposure / Q000009:adverse effects*; D008168:Lung / Q000737:chemistry / Q000187:drug effects* / Q000276:immunology / Q000648:ultrastructure; D008297:Male; D008422:Materials Testing; D018986:Motor Vehicles; D009784:Occupational Diseases / Q000139:chemically induced / Q000276:immunology / Q000473:pathology / Q000517:prevention & control; D011482:Protective Devices / Q000009:adverse effects*; D051381:Rats; D017208:Rats, Wistar; D020545:Respiratory Mucosa / Q000737:chemistry / Q000187:drug effects / Q000276:immunology / Q000648:ultrastructure; D014018:Tissue Distribution; D023382:Toxicity Tests, Acute
D017632:Asbestos, Serpentine; D004391:Dust; D017638:Asbestos, Crocidolite
Amphibole asbestos; Brake dust; Chrysotile; Inhalation toxicology; Lung/pleura; Pathology