Recent Evidence on Biopersistence of Chrysotile in comparison with Amphiboles and Substitutes like Cellulose, Ceramic Glass wool, etc.
There is recent evidence on Biopersistence of Chrysotile fibre which shows that “Chrysotile” fibre gets cleared from lungs in approximately 11 days as compared to other fibres like, Amosite, Cellulose, Ceramic, Aramid Stone Wool, Glass wool and Crocidolite which take 39 – 1000 days for clearance.
The Study has been undertaken by Dr. David Bernstein, Consultant in Toxicology, Geneva, Switzerland, Dr. Rick Rogers, Rogers Imaging Corporation, Needham , Massachusetts and Dr. Paul Smith, Research & Consulting Company Ltd. Switzerland .
The final results through 1 year after cessation of exposure clearly establish that Chrysotile asbestos, a serpentine mineral to be notably different from amphibole asbestos such as amosite, crocidolite and tremolite in that Chrysotile once inhaled is rapidly removed from the lung while the amphiboles persist. This has been demonstrated for three different Chrysotile samples from Canada , the United States and Brazil .
These results fully support the differentiation of Chrysotile from amphiboles reported in recent evaluation of available epidemiological studies. This study has been published in the Journal Inhalation Toxicology, 2004. A comparative Biopersistence data (half-time lung clearance) is given below:
|CHRYSOTILE||APPROX. 11 days||(1)|
|CERAMIC FIBRES (RCF 1)||60 days||(4)|
|STONE WOOL (MMVF21)||46 days||(5)|
|GLASS WOOL (MMVF10)||39 days||(5)|
- The three recent studies by Bernstein et al
- Bernstein et al (1999) 7 th Int. Symp. Part Toxicol. Maastrich
- Muhle & Bellman (1997) Ann. Occup. Hyg. 41:184-188
- Bellman et al (2000) Toxicol. Sci.54:237-250
- Franhofer Institute (1998) Report, Hannover , August 1998
- Bernstein, et al (1996) Inhalation Toxicology 8:345-385