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Topic: Chrysotile

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  Chrysotile - Wikipedia, the free encyclopedia
Chrysotile is an asbestiform sub-group within the serpentine group of minerals.
There are three known species of chrysotile: clinochrysotile (which is monoclinic), orthochrysotile (which is orthorhombic) and parachrysotile (which is also an orthorhombic polymorph).
Chrysotile, a form of asbestos, is a proven human carcinogen (List of IARC Group 1 carcinogens).
en.wikipedia.org /wiki/Chrysotile   (272 words)

 Asbestos Minerals,Chrysotile Asbestos,Asbestos Information,Asbestos Properties
Chrysotile asbestos, the fibrous variety of the mineral serpentine, is by far the most important type of asbestos.
Chrysotile and tremolite, which in pure form contain no iron, tend to be white, together with actinolite and anthophyllite are grouped together as "white asbestos" and classified as UN2590 (under the United Nations chemical ID numbering system).
Chrysotile is the only one in which the sheets are continuous and bend to form continuous tubes, which give the mineral the fibrous habit related to asbestos.
www.mineralszone.com /minerals/asbestos.html   (2087 words)

 Chrysotile and tremolite asbestos fibres in the lungs and parietal pleura of Corsican goats -- Dumortier et al. 59 (9): ...
Chrysotile and tremolite asbestos fibres in the lungs and parietal pleura of Corsican goats -- Dumortier et al.
Chrysotile and tremolite asbestos fibres in the lungs and parietal pleura of Corsican goats
the proportions of chrysotile and amphiboles are caused by a
oem.bmjjournals.com /cgi/content/full/59/9/643   (1928 words)

 NOPP - Addition of Chrysotile Asbestos to the PIC Procedure of the Rotterdam Convention
Pulmonary loading with chrysotile is proportional to duration and the intensity of asbestos exposure, but it is inversely proportional to the elapsed time since the last exposure, due to the lower biopersistance of chrysotile.
The biopersistance of chrysotile verses the amphiboles is actively debated because it is often used to justify why the potency, with respect to carcinogenicity, is less for chrysotile.
Calidria chrysotile fibres, a standard chrysotile used for testing, clear from the lung more rapidly, with a half life of 7 hours, for fibres longer than 20 µm (asbestos fibres with a length of less than 20 µm, are considered to be less persistent).
www.ec.gc.ca /nopp/docs/consult/Rotterdam/ca/en/chrysotileHealth-BG.cfm   (2957 words)

 Micro Analytical Laboratories, Inc.
Chrysotile fibers are formed by sheetlike crystals that roll into tight tubes and may exhibit several forms.
Chrysotile fibers are often obscured by other materials in the sample, such as clay, and only the ends of fibers may be exposed.
Chrysotile is also chemically resistant and has been used to make laboratory bench tops that prevent chemical stains.
www.labmicro.com /chrysotile.htm   (498 words)

 NOPP - Addition of Chrysotile Asbestos to the PIC Procedure of the Rotterdam Convention
Chrysotile, or white asbestos, of the phyllosilicates family, is the fibrous form of the mineral antigorite and is the sole member of the serpentine group.
Chrysotile is also used in friction products such as brake linings and clutch facings (7% of global uses) and in textiles, clothing and various other uses (3% of global uses).
Chrysotile represents about 99% of the world’s current asbestos production, which is estimated at 1.97 million tonnes in 2002.
www.ec.gc.ca /nopp/docs/consult/Rotterdam/ca/en/chrysotileBG.cfm   (1467 words)

 Chrysotile | Asbestos Resource Guide (via CobWeb/3.1 planetlab2.cs.umd.edu)   (Site not responding. Last check: 2007-11-07)
Chrysotile is a fibrous mineral which does not burn or rot.
This unique combination of properties makes chrysotile an extremely useful material which has been established, for many decades, as a major component of lightweight reinforced cement products, friction materials, high temperature seals and gaskets and a host of other applications.
Chrysotile has been known for over 2000 years, being used initially for cremation cloths, oil lamp wicks and other textiles.
www.asbestos-now.com.cob-web.org:8888 /chrysotile   (269 words)

 Chrysotile Asbestos - JustMeso.com
Chrysotile asbestos is a type of asbestos known to cause mesothelioma.
Chrysotile asbestos, or serpentine, is a polymorphous, magnesium-rich mineral that is typically found in metamorphic rocks.
Chrysotile asbestos was predominantly mined in Canada with only small amounts of the ore having been produced from mines in the United States.
www.justmeso.com /asbestos/chrysotile.html   (224 words)

 Chrysotile asbestos (EHC 203, 1998)   (Site not responding. Last check: 2007-11-07)
The deposition of inhaled chrysotile asbestos is dependent upon the aerodynamic diameter, the length and the morphology of the fibre.
Chrysotile is introduced into water by the weathering of chrysotile-containing rocks and ores, in addition to the effects of industrial effluents and atmospheric pollution (Canada Environmental Health Directorate, 1979).
Chrysotile is by far the predominant asbestos fibre consumed today, e.g., in the USA 98.5% asbestos consumption in 1992 was chrysotile (Pigg, 1994).
www.inchem.org /documents/ehc/ehc/ehc203.htm   (13936 words)

 NOPP - Addition of Chrysotile Asbestos to the PIC Procedure of the Rotterdam Convention
However, they determined that the lung-cancer risk among chrysotile workers continuously exposed to one chrysotile fibre per cubic centimetre of air (1 f/cc) is equivalent to the risk incurred by a person smoking two cigarettes a week.
Although, chrysotile is considered to be a less potent carcinogen when compared to the amphiboles, it is still considered a carcinogen, therefore its use is predominantly restricted to products with non-friable fibers, or fibers trapped in a solid matrix.
The objective of the responsible-use policy is to supply chrysotile only to those companies who are in compliance or which have provided formal written commitment and action plans to bring their operations into compliance with national regulations.
www.ec.gc.ca /nopp/docs/consult/Rotterdam/ca/en/chrysotileRM-BG.cfm   (3331 words)

 NTP: Abstract for TR-295 - Chrysotile Asbestos
The offspring from mothers exposed to SR chrysotile were similar in body weight to the controls at birth but were slightly smaller (13%) at weaning and remained so throughout their lifetimes.
Although not statistically significant (P=0.08) compared with concurrent controls (0/85), the incidence of these neoplasms was highly significant (P=0.003) when compared with the incidence of epithelial neoplasms (benign and malignant combined) of the large intestine in the pooled male control groups of all the NTP oral asbestos lifetime studies (3/524, 0.6%).
The cocarcinogenesis studies of 1,2-dimethylhydrazine dihydrochloride and IR chrysotile asbestos were considered inconclusive for determining whether IR chrysotile asbestos had either a tumor-enhancing or protective effect, although an increased incidence of neoplasms was observed in the kidneys of female rats exposed to DMH plus IR chrysotile as compared with those exposed to DMH alone.
ntp.niehs.nih.gov /index.cfm?objectid=07076FD7-F931-E4FC-2AC9E40653488694   (874 words)

 Asbestos - Malignant Mesothelioma Information
Chrysotile makes up approximately 90% to 95% of the asbestos contained in buildings of the United States.
Some researchers in the asbestos industry have made the claim that chrysotile asbestos is not dangerous because it is short and curly, and thus when inhaled, it is less likely to become lodged in the deepest parts of the lungs.
Also, animal studies have shown that when chrysotile is inhaled, it does become lodged in the deepest parts of the lungs and is not easily removed by the immune system.
www.allaboutmalignantmesothelioma.com /asbestos.htm   (548 words)

 Mesothelioma Cases - Chrysotile Asbestos in Drinking-Water
Results of cohort studies of workers almost exclusively exposed to chrysotile asbestos and considered by the Task Group to be most relevant to this evaluation are summarised in Table 23 and described in section
Studies that contribute less to our understanding of the effects of chrysotile, due primarily to concomitant exposure to amphiboles or to limitations of design and reporting, are presented in section
Available data on effects of exposure to chrysotile asbestos (specifically) in the general environment are restricted to those in populations exposed to relatively high concentrations of chrysotile asbestos in drinking-water, particularly from serpentine deposits or asbestos-cement pipe.
www.mesotheliomahelpcenter.com /6mesothelioma.htm   (788 words)

 Vitronectin adsorption to chrysotile asbestos increases fiber phagocytosis and toxicity for mesothelial cells -- Wu et ...
Vitronectin adsorption to chrysotile asbestos increases fiber phagocytosis and toxicity for mesothelial cells -- Wu et al.
Percent of adsorption of radiolabeled BSA and VN to crocidolite and chrysotile fibers.
X-ray photelectron spectroscopy and chemical study of the adsorption of biological molecules on chrysotile asbestos surface.
ajplung.physiology.org /cgi/content/full/279/5/L916   (5768 words)

 Types of Asbestos - Amphibole Asbestos, Serpentine Asbestos
Also called white asbestos, chrysotile asbestos is unique in that it has a serpentine fiber-formation (curled fibers) compared to the amphibole fiber-formation (straight, needle-like fibers) of the other five types.
Chrysotile asbestos is less friable than other types of asbestos, meaning that it is less-likely to be inhaled.
Because chrysotile asbestos is less likely to be inhaled, it is deemed the safest of the asbestos types; some evidence even suggests that chrysotile is harmless when inhaled.
www.phhlaw.com /PracticeAreas/PracticeAreaDescriptions112.asp   (318 words)

 Eliminating asbestos from fireproofing materials
Chrysotile asbestos is considered relatively nonreactive chemically, but several approaches for the chemical elimination of chrysotile have been reported (18–23).
These conditions are necessitated by chrysotile’s crystal structure (which consists of alternating layers of magnesia and silica) and by the incomplete removal of magnesia from the structure.
The cube composition was 63.3% gypsum, 25% vermiculite, and 11.7% chrysotile.
pubs.acs.org /hotartcl/ci/00/jun/block.html   (4728 words)

 Asbestos Nations Block Placement of Chrysotile on Danger List
Canada requested that the chrysotile asbestos decision be postponed to allow for completion of its national consultations on the issue.
Chrysotile is the only kind of asbestos mined in Canada, and both asbestos producers and Health Canada claim it can be used safely if it is properly processed.
Lung cancer is caused by chrysotile, anthophyllite, amosite, and crocidolite asbestos in asbestos workers who smoke cigarettes.
www.ens-newswire.com /ens/nov2003/2003-11-18-02.asp   (1315 words)

 9 Questions and Answers on Chrysotile and Health - Law Firm Paul, Hanley & Harley LLP Attorneys Berkeley, California
The authors indicate that their study supports a former finding of a possible adaptive clearance of chrysotile and conclude that their findings support the hypothesis that adverse effects are associated rather with the fibres that are retained (amphiboles), than with the ones being cleared (largely chrysotile).
The authors indicate: “Thus the general results of this mortality survey suggest that the population of the chrysotile asbestos-cement factory studied are not at any excess risk in terms of total mortality, all cancer mortality, cancers of the lung and the bronchus, or gastrointestinal cancers”.
Studies undertaken in areas where chrysotile cement materials are widely used show that their contribution to the presence of chrysotile fibres in the environment is not significant.
www.phhlaw.com /CM/Articles/Articles53.asp   (3683 words)

 Chrysotile Asbestos - Chrysotile Fibres, Chrysotile Exposure
The slopes of the relationship between cumulative exposure to chrysotile and the relative risk of lung cancer are summarized in Table 23 for those studies that reported this information.
The slopes of 0.01 and 0.03 reported for the two studies of the chrysotile-exposed textile workers conducted on overlapping populations, as well as the slope of 0.007 from one of the two plants (plant 2) of cement workers in the study of Hughes et al.
The relationship between chrysotile exposure and lung cancer risk was observed to be virtually unaffected by control for exposure to mineral oils in these analyses.
www.mesotheliomahelpcenter.com /4-a-mesothelioma.htm   (775 words)

 Reports, publications   (Site not responding. Last check: 2007-11-07)
Professor Langer considered the transformation of the chrysotile fibre subjected to high temperatures, and examined its concentration in a garage where asbestos-containing brake pads were used.
Using heating studies and milling as an approximation of thermal and mechanical shear stress that chrysotile is subjected to on a brake lining, biological blunting is shown to begin at much lower temperature than expected.
By objecting to the inclusion of chrysotile, these numerous producing and consuming countries have indicated to the whole world that this natural fibre, can and is, being used safely and responsibly.
www.ass-chrysotile.ru /reports.htm   (2012 words)

 Asbestos and Libby Health- The Science
Asbestos is the name given to a group of six different fibrous minerals (amosite, chrysotile, crocidolite, and the fibrous varieties of tremolite, actinolite, and anthophyllite) that occur naturally in the environment.
Amphibole asbestos fibers are generally brittle and often have a rod- or needle-like shape, whereas chrysotile asbestos fibers are flexible and curved.
Chrysotile, also known as white asbestos, is the predominant commercial form of asbestos; amphiboles are of minor commercial importance.
www.umt.edu /Libbyhealth/science/online_resources/atsdr_asbestos.htm   (4293 words)

 Burnham Brown - Attorneys at Law, Oakland, California   (Site not responding. Last check: 2007-11-07)
Chrysotile is the sixth type of silicate mineral grouped under the heading “asbestos” but, in fact, has significantly different properties from the other five as it is part of the serpentine group of minerals.
The chrysotile defense helps to insert the smoking gun into the courtroom discussion, in the sense that it presents evidence of amphiboles as a much more toxic and carcinogenic material used by the plaintiff and a much more likely cause of his or her disease.
The chrysotile defense allows the defense to undermine the credibility of Plaintiffs’ experts who are willing to go out on a limb and claim no difference between chrysotile and amphibole in the face of overwhelming evidence to the contrary.
www.burnhambrown.com /publications/article.cfm?pubid=101   (4016 words)

 Ultramafic-hosted Chrysotile Asbestos - Mineral Deposit Profiles, B.C. Geological Survey
Chrysotile asbestos deposits are generally considered to be syntectonic and to form during the later stages of deformation.
Chrysotile stability field; proximity to a fault that is active during change in the orientation of stress field; limited subsequent deformation and no subsequent medium to high grade metamorphism after the asbestos formation.
The chrysotile forms as the result of fluid flow accompanied by deformation where water gains access to partly or wholly serpentinized ultramafics along fault and shear zones.
www.em.gov.bc.ca /Mining/Geolsurv/MetallicMinerals/MineralDepositProfiles/Profiles/M06.htm   (1757 words)

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