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The relative risk for asbestos is listed as 2 based on how it was used 20 to 50 years ago (without differentiating whether it was chrysotile or amphibole asbestos). It is also interesting to note that arsenic and chromium have higher relative risks and that none of the other agents listed are banned.
The WHO also cites the more recent publication by Driscoll et al. (2005) in support of the statements entitled:
Driscoll T, Nelson Dl, Steenland K, Leigh J, Concha·Barrientos M, Fingerhut M, Prüss-Ustiln A: The global burden of non-malignant respiratory disease due to occupational airborne exposures. Am J Ind Med. 2005, 48;432-45,
In the paper by Driscoll et al. the authors cite the more recent and considerably more complete publication by Hodgson and Darnton (2000) on asbestos risk which differentiates chrysotile from amphibole asbestos and not the older paper by Steenland et al. (1996).
Driscoll et al. states that:
“This combined estimate is based on best estimates of risk of 400 per 100 000/fibre.year per ml for crocidolite, 65 per 100 000/fibre.year per ml for amosite and 2 per 100 000/fibre.year per ml for chrysotile, and the changing mixture of amphiboles and chrysotile that has characterised exposure 20 and 50 years ago [Hodgson and Darnton, 2000].”
In another publication from the WHO entitled:
Prüss-Ustiln A, Vickers C, Haefliger P, Bertollini B. Knowns and unknowns on burden of disease due to chemicals; a systematic review. Environmental Health. 2011, 10:9.
The authors state:
“The global burden of disease attributable to asbestos has been estimated to amount to 107,000 deaths and 1,523,000 DALYs for the three mentioned diseases in 2004.”
Prüss-Ustiln et al. (2011) cite three references in support of this statement. These include the Concha-Barrientos, et al. (2004) publication discussed above which clearly does not attribute the effect to chrysotile; the publication by Driscoll et al. (2005) which also clearly differentiates chrysotile effects from those from amphibole asbestos; and the WHO 2009 report entitled “Global health risks: mortality and burden of disease attributable to selected major risks4” which does not ever mention the word chrysotile.
In the paper by Prüss-Ustiln et al. (2011), chrysotile is also not ever mentioned in the text. Any possible relationship of the “107,000 deaths” to chrysotile is certainly not supported by this paper. The references cited by Prüss-Ustiln et al. (2011) for the 107,000 deaths per year are the same as mentioned above and are based upon the exposure to all types of asbestos (amosite, crocidolite and chrysotile asbestos) at the exposure concentrations that occurred 20 to 50 years ago.
From the publication by Hodgson and Darnton, 2000, based upon exposure levels 20-50 years ago and the analysis of studies as “chrysotile” which actually had exposures to amphibole asbestos (Bernstein et al., 2013), the calculated mesothelioma risk for chrysotile is 2 per 100 000/fibre.year per ml. As explained by Bernstein et al. (2013), with the elimination of amphibole use today and under the controlled use employed which greatly reduces potential exposure, the risk for mesothelioma today would be very low. Similarly, Ezzati et al. (2004) stated that: “little excess lung cancer is expected from low exposure levels”.
In addition the most recent evaluation of scientific evidence performed by the International Agency for Research on Cancer (IARC Monograph 100c) which stated that all forms of asbestos (chrysotile, crocidolite, amosite, tremolite, actinolite and anthophyllite) are carcinogenic to humans (Group 1) was also based upon exposure concentrations that occurred 20 to 50 years ago using studies as chrysotile only in which there was amphibole asbestos exposure. The IARC classification is a hazard classification based upon whether any study has reported an effect at any time and at any exposure concentration. It does not provide an assessment of risk today from exposure to chrysotile alone (with no amphibole asbestos) at exposure concentration that occur with controlled use.
The documents put forward by the WHO clearly do not support the statement that the 107,000 deaths per year are occurring today and provide no basis for attributing these to chrysotile.4 WHO, 2009 ISBN 978 92 4 156387 1
David Bernstein, Ph.D.
Bernstein D, Dunnigan J, Hesterberg T, Brown R, Velasco JA, Barrera R, Hoskins J, Gibbs A. 2013 Health risk of chrysotile revisited. Crit Rev Toxicol. 2013 Feb;43(2):154-83.
Regional variations in German mesothelioma mortality rates: 2000–2010
Cancer Causes & Control (2014) Volume 25, Issue 5, pp. 615-624
Sara J. Schonfeld, Valerie McCormack, Mark J. Rutherford, Joachim Schüz
This is a study on geografical differences in mesothelioma mortality rates in two parts of Germany with data coming from the former West Germany which had access to amphibole sources from South Africa, while East Germany relied almost exclusively on chrysotile from Canada, and possibly other chrysotile-only sources.
As mesothelioma occurs many (≥30) years after asbestos exposure, contemporary rates likely reflect exposures in the 1960–1970s. During this period, political division between West and East Germany led to differences regarding the import and consumption of asbestos of asbestos fiber types, West germany having access to large imports of amohiboles, while East germany The authors focused in particular on regional variations in mesothelioma mortality rates in in 2000–2010. They calculated truncated (≥40 years) age-standardized mesothelioma mortality rates (ASRs40+) per 100,000 person-years. There were 12,854 mesothelioma deaths at ages ≥ 40 years in Germany during 2000–2010. ASRs40+ were higher in West (males 4.4; females 0.8) than East (males 1.7; females 0.6) Germany.
The authors conclude that these geographical differences in mesothelioma mortality rates are consistent with heterogeneous historical asbestos exposures. They suggest that differences may also exist for other asbestos-related cancers and should be investigated.
Incidentally, this study appears in line with many other studies confirming the vast difference with regard to the mesotheliomagenic potential between amphiboles and chrysotile. Among such studies are :
South African experience with asbestos related environmental mesothelioma: Is asbestos fiber type important?
Regulatory Toxicology and Pharmacology (2008) Volume 52, Issue 1, Supplement, pp. S92–S96
Neil Whitea, †, Gill Nelsonb, Jill
It well known that South Africa (SA),has mined and milled all three commercially important asbestos minerals. Proven cases of mesothelioma have been linked with environmental exposure to asbestos. In this study, the authors illustrate the importance of fiber type in the occurrence of environmental mesothelioma. Studies have reviewed the source of occupational or environmental asbestos exposure in 504 histologically proven cases of mesothelioma in. 23% of cases were thought to be related to environmental exposure to asbestos. The vast majority of these cases were related to exposure to crocidolite mining activities in the Northern Cape Province. No cases were reported with exposure to South African chrysotile.
In the vast majority of cases of mesothelioma, environmental exposure to asbestos occurred in the Northern Cape Province, in proximity to mines, mills and dumps where crocidolite was processed. Crocidolite appears to be far more mesotheliomagenic than amosite, and chrysotile has not been implicated in the disease. This is true for both occupationally and environmentally exposed individuals.
The health risk of chrysotile asbestos
Current Opinion in Pulmonary Medicine (2014) Vol. 20, No. 4, 389-392
This review clarifies the differences between the two mineral families (chrysotile and amphiboles) referred to as « asbestos » The author summarizes the scientific basis for understanding the important differences in the toxicology and epidemiology of these two minerals. Biopersistence studies and sub-chronic inhalation toxicology studies have shown that exposure to chrysotile at up to 5,000 times the current threshold limit value (0.1 fibers/cm3) produces no pathological response. These studies demonstrate as well that following short-term exposure the longer chrysotile fibers rapidly clear from the lung and are not observed in the pleural cavity. In contrast, short-term exposure to amphibole asbestos results quickly in the initiation of a pathological response in the lung and the pleural cavity.
The author concludes that the valuation of the toxicology and epidemiology studies of chrysotile indicates that it can be used safely under controlled use. In contrast, even short-term exposure to amphibole asbestos can result in disease.
The review is available here.
Potential health hazards associated with exposures to asbestos-containing drywall accessory products: A state-of-the-science assessment
Critical Reviews in Toxicology (2012) Vol. 42, No. 1 , Pages 1-27
Amanda D. Phelka1, Brent L. Finley2
In this review on the risk assocated with the presence of asbestos as an ingredient in most industrial and consumer drywall accessory products such as patching compounds. The authors mention that in 1977, the Consumer Product Safety Commission (CPSC) had issued a ban of consumer patching compounds containing “respirable, free-form asbestos” based on their prediction of exceptionally high rates of asbestos-related diseases among individuals using patching compounds for as little as a few days.
The authors provide a comprehensive review and analysis of the scientific studies assessing fiber type and dimension, toxicological and epidemiological endpoints, and airborne fiber concentrations associated with joint compound use. They conclude that:
Asbestos Content of Heavy Equipment Brake-Wear Debris and Associated Airborne Exposure During Brake Work
Society of Toxicology 53rd Annual Meeting and ToxExpo Phoenix, AZ. March 23-27, 2014
Grespin, M.E., E.D. Donovan, R.J. Ward, A.K. Madl, and B.L. Finley
EVOLUTION OF WORLD PRODUCTION AND CONSUMPTION OF ASBESTOS
|MAJOR PRODUCERS IN 2012|
|WORLD CONSUMPTION IN 2011 AND 2012|
Toxicology and Applied Pharmacology (2014) Vol 276, No. 1, pp. 28-46
David M. Bernstein, Rick Rogers, Rosalina Sepulveda, Peter Kunzendorf, Bernd Bellmann, Heinrich Ernst, James I. Phillips
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 T1/2 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 T1/2 > 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 brake drums would not initiate a pathological response in the lung following short term inhalation.
Posted online on January 9, 2014. (doi:10.3109/08958378.2013.845273)
James O. Rasmuson1, Victor L. Roggli2, Fred W. Boelter3, Eric J. Rasmuson1, and Charles F. Redinger4
A study conducted to compare retrospective exposure assessment (REA) and asbestos lung burden assessment (LBA). Both REA and pathology assessment (LBA) are reliable and complementary predictive methods to characterize asbestos exposures. Correlation analysis between the two methods effectively validates both REA methodology and LBA procedures within the determined precision, particularly for cumulative amphibole asbestos exposures since chrysotile fibers, for the most part, are not retained in the lung for an extended period of time.
Journal of Immunotoxicology
Posted online on October 28, 2013. (doi:10.3109/1547691X.2013.847510)
Aaron Ferro1, Christian Nash Zebedeo2, Chad Davis2, Kok Whei Ng2, and Jean C. Pfau2
This srudy aims to demonstrate that while exposure to amphibole asbestos has been associated with production of autoantibodies in mice and humans, and increases the risk of systemic autoimmune disease, epidemiological studies of chrysotile exposure have not indicated a similar induction of autoimmune responses. To demonstrate this difference in controlled exposures in mice, serum ANA/ENA (antinuclear antibodies/extractable nuclear antigens) were analysed following chalenges with both amphibole and chrysotile.
Overall, the results suggest that, while there may be an inflammatory response to both forms of asbestos, there is an autoimmune response in only the amphibole-exposed, but not the chrysotile-exposed mice. These data have critical implications in terms of screening and health outcomes of asbestos-exposed populations.
Critical reviews in Toxicology, October 2012, Vol. 42, No. 9 , Pages 703-731
Ellen P. Donovan1, Brooke L. Donovan1, Meg A. McKinley1, Dallas M. Cowan2, Dennis J. Paustenbach1
In this review article, the authors have conducted a literature review in order to characterize reported cases of asbestos-related disease among household contacts of workers occupationally exposed to asbestos. In some 60 articles, cases of asbestos-related disease are described and thought to be caused by para-occupational exposure, over 65% of these cases were in persons who lived with workers classified as miners, shipyard workers, insulators, or others involved in the manufacturing of asbestos-containing products, with nearly all remaining workers identified as craftsmen. 98% of the available lung samples of the persons with diseases indicated the presence of amphibole asbestos. The authors indicate that the literature is dominated by case reports, the majority of which involved household contacts of workers in industries characterized, generally, by high exposures to amphiboles or mixed mineral types. The available data do not implicate chrysotile as a significant cause of disease for household contacts.
Posted online on October 17, 2013. (doi:10.3109/01913123.2013.821194)
Ronald F. Dodson, PhD1, Eugene J. Mark, MD2, and Lee W. Poye, BS3 1Dodson Environmental Consulting, Inc. and ERI Environmental Consulting, Inc., Tyler, Texas USA
This present case study reports on tissue burden of fibrous dust in a person who used a vermiculite material (Zonolite) as an attic insulator some 50 years prior to her death. The exposure occurred in her private residencies. She potentially had exposures to wall board/joint compounds during renovations. She additionally was reported to occasionally be involved in occupational activity, including drilling holes in presumed asbestos-containing electrical boxes. Tissue burden analysis revealed the presence of noncommercial amphibole asbestos fibers and consistent presence in the lung and lymph samples of Libby amphibole fibers. The findings of Libby amphibole fibers in human tissue can be attributed to exposure to Libby vermiculite. This is an illustration that analytical transmission electron microscopy can distinguish these structures from “asbestos” fibers. The findings also indicate that a population of these structures is biodurable and retained in the tissue years after first/last exposure.
Emily Goswami; Valerie Craven; David L Dahlstrom; Dominik Alexander; Fionna Mowat
Int J Environ Res Public Health 10, 5629 (2013)
This review offers a meta-analysis that evaluates epidemiologic studies of asbestos-related disease or conditions (mesothelioma, lung cancer, and pleural and interstitial abnormalities) among domestically exposed individuals and exposure studies that provide either direct exposure measurements or surrogate measures of asbestos exposure.
The studies are limited with regard to lung cancer (n = 2). Several exposure-related studies describe results from airborne samples collected within the home (n = 3), during laundering of contaminated clothing (n = 1) or in controlled exposure simulations (n = 5) of domestic exposures, the latter of which were generally associated with low-level chrysotile-exposed workers. Lung burden studies (n = 6) were also evaluated as a surrogate of exposure. In general, available results for domestic exposures are lower than the workers' exposures. Recent simulations of low-level chrysotile-exposed workers indicate asbestos levels commensurate with background concentrations in those exposed domestically.
Inhalation Toxicology, August 2013, Vol. 25, No. 9 , Pages 517-524
Pilar Eguía-Aguilar1, Mario Pérezpeña-Díazconti1, and Francisco Arenas-Huertero1,2
Ferruginous bodies (FBs) are iron-coated entities that form in the body around inorganic fibers or other particulates. Studies of FB have been conducted consistently in the lungs of adults but have not been explored in children during the past 20 years. The objective of this study was to quantify the FBs, classify them as to morphological type and conduct a mineralogical analysis using the energy dispersive X-ray microanalysis (EDXA) with samples obtained from 72 autopsies performed on children.
Three grams of lung tissue were digested in commercial bleach, and all the FB found were quantified. The FB from the positive cases was analyzed by EDXA. Results show that 17% of cases presented FB with a median concentration of 5.7 ferruginous bodies per gram of dry weight (FB/g). Larger quantities of FB were recovered from the lungs of rural residents, at concentrations of 11.33 FB/g. Ten cases of children under 5 years of age also presented 5.7 FB/g, but none of these groups showed significant differences when compared to populations of children residing in Mexico City or to children over 5 years of age (p > 0.05). Type-1 FB was the predominant morphological form present. All FBs were aluminosilicates. It can be concluded that Mexican children retain FBs at low concentrations. All the cores of the FB analyzed in this study were aluminosilicates. Only one contained kaolinite, while the other 10 consisted of some kind of feldspar or clay-like mineral and may thus reflect intramural exposure in children.
Ultrastructural Pathology : Posted online on October 17, 2013.
Ronald F. Dodson, PhD1, Eugene J. Mark, MD2, and Lee W. Poye, BS3
This is a case study reporting on tissue burden of fibrous dust in a women who used a vermiculite material (Zonolite) as an attic insulator some 50 years prior to her death.
The exposure occurred in two construction/renovation projects in her private residencies. She potentially had exposures to wall board/joint compounds during renovations. The tissue burden analysis revealed the presence of noncommercial amphibole asbestos fibers and consistent with the presence in the lung and lymph samples of Libby amphibole fibers. The findings of Libby amphibole fibers in human tissue can be attributed to exposure to Libby vermiculite. There is no report of chrysotile fibers accumulation in her lung tissues. This study illustrates that analytical transmission electron microscopy can distinguish these structures from "asbestos" fibers, and indicates that a population of these structures is biodurable and retained in the tissue years after first/last exposure.
Journal of Immuntoxicoloy
Posted online on October 28, 2013. (doi:10.3109/1547691X.2013.847510)
Aaron Ferro1, Christian Nash Zebedeo2, Chad Davis2, Kok Whei Ng2, and Jean C. Pfau2
1Pacific Northwest University of Health Sciences, College of Osteopathic Medicine, Yakima, WA, USA and 2Idaho State University, Department of Biological Sciences, Pocatello, ID, USA
It is known that exposure to amphibole asbestos has been associated with production of autoantibodies in mice and humans, and also increases the risk of systemic autoimmune disease.
Eight months after the final treatments with amphiboles and chrysotile, the authors exanined the changes in serum antinuclear antibodies (ANA), antibodies to extractable nuclear antigens (ENA), serum cytokines, and immunoglobulin isotypes. The results show that amphiboles, but not chrysotile, asbestos increases the frequency of ANA/ENA in mice. Amphibole and chrysotile both increased multiple serum cytokines, but only amphibole increased IL-17, an interleukin which induces the production of pro-inflammatory cytokines. Overall, the results suggest that, while there may be an inflammatory response to both forms of asbestos, there is an autoimmune response in only the amphibole-exposed, but not the chrysotile-exposed mice.
Crit Rev Toxicol. 2012; 42(9):703-31 (ISSN: 1547-6898)
Donovan EP; Donovan BL; McKinley MA; Cowan DM; Paustenbach DJ, ChemRisk LLC, San Francisco, CA 94105, USA. email@example.com
In this review article, the authors have covered over 200 published articles where some Nearly 60 articles described cases of asbestos-related disease thought to be caused by para-occupational exposure. Over 65% of these cases were in persons who lived with workers classified as miners, shipyard workers, insulators, or others involved in the manufacturing of asbestos-containing products, with nearly all remaining workers identified as craftsmen. 98% of the available lung samples of the persons with diseases indicated the presence of amphibole asbestos. Eight studies provided airborne asbestos concentrations during (i) handling of clothing contaminated with asbestos during insulation work or simulated use of friction products; (ii) ambient conditions in the homes of asbestos miners; and (iii) wearing previously contaminated clothing. This review indicates that the literature is dominated by case reports, the majority of which involved household contacts of workers in industries characterized, generally, by high exposures to amphiboles or mixed mineral types. The available data do not implicate chrysotile as a significant cause of disease for household contacts.
Ann Occcup Hyg (2012) Vol 56, 660-670,
Barbieri GP, Mirabelli D, Somigliana A, Cavone C, Merler E
Epidemics of malignant mesothelioma are occurring among inhabitants of Casale Monferrato and Bari never employed in the local asbestos-cement (AC) factories. Analysis was performed by a scanning electron microscope equipped with X-ray microanalysis wet (formalin-fixed) lung tissue samples from eight mesothelioma patients who lived in Casale Monferrato or Bari and underwent surgery.
The lung fibre burden ranged from 110 000 to 4 300 000 fibres per gram of dry lung (f/g) and was >1 000 000 f/g in three subjects. Of the eight mesothelioma cases, only amphibole fibres were detected in four cases, and mixed fiber types were detected in the other four cases. Environmental exposures had ceased at least 10 years before samples were taken.
The authors conclude that environmental exposure to a mixture of asbestos fibres may lead to a high lung fibre burden of amphiboles years after exposure cessation.
Critical Review in Toxicology. January 2012, Vol. 42, No. 1 , Pages 1-27
Amanda D. Phelka1, Brent L. Finley2
1ChemRisk LLC, Chicago, IL, USA2
ChemRisk LLC, San Francisco, CA, USA
Until the late 1970s, chrysotile asbestos was an ingredient incorporated in most industrial and consumer drywall accessory products manufactured in the US. In 197. Prediction of exceptionally high rates of asbestos-related diseases among individuals using patching compounds for as little as a few days had led the Consumer Product Safety Commission (CPSC) to issue a ban of consumer patching compounds containing "respirable, free-form asbestos" Although hundreds of thousands of workers and homeowners handling these products may have experienced exposure to asbestos prior to the ban, there has been no systematic effort to summarize and interpret the information relevant to the potential health effects of such exposures. The review is meant to provide a comprehensive review and analysis of the scientific studies assessing fiber type and dimension, toxicological and epidemiological endpoints, and airborne fiber concentrations associated with joint compound use. The authors find that asbestos in drywall accessory products is primarily short fiber (< 5 µm) chrysotile, that estimated cumulative chrysotile exposures experienced by workers and homeowners are below levels known to be associated with respiratory disease, and mortality studies of drywall installers have not demonstrated a significantly increased incidence of death attributable to any asbestos-related disease.
The authors state that contrary to the alarmist predictions of the CPSC, the current weight of evidence does not indicate any clear health risks associated with the use of asbestos-containing drywall accessory products.
Inhalation Toxicology. October 2011, Vol. 23, No. 12 , Pages 681-688
Gary M. Marsh1, Ada O. Youk1, Victor L. Roggli2
1Department of Biostatistics, Graduate School of Public Health, Center for Occupational Biostatistics and Epidemiology,
University of Pittsburgh, Pittsburgh, PA, USA
2Department of Pathology, Duke University Medical Center, Durham, NC, USA
The authors investigated the lung levels of commercial and non-commercial amphiboles (principally tremolite as a marker for chrysotile asbestos) in brake repair workers with mesothelioma. 15 persons whose only known exposure to asbestos was through brake repair work were investigated to evaluate whether case-reported duration of employment as a brake repair worker predicted lung levels of commercial amphiboles or tremolite. The authors found that their data provided no evidence that duration of employment as a brake repair worker was a predictor of lung levels of tremolite or commercial amphiboles. Their findings also suggest that elevated lung levels of tremolite in the lungs of brake repair workers with elevated levels of amphiboles arose from concurrent exposures to commercial amphibole and chrysotile asbestos in occupational settings other than brake repair work. The weight of the scientific evidence does not support a role for occupational exposure to brake dust and other friction products in the development of mesothelioma.
Int J Hyg Environ Health. 2013 Jul 20. pii: S1438-4639
Bourgault MH, Gagné M, Valcke M.
Institut national de santé publique du Québec (INSPQ), Montréal, Québec, Canada.
Electronic address: firstname.lastname@example.org.
Recent published data on asbestos environmental concentrations in Thetford Mines, a mining city in Quebec, Canada, provided an opportunity to undertake a prospective cancer risk assessment in the 'general population' exposed to these concentrations. This 'general population' includes smokers and non-smokers, mining as well as non-occupationaly exposed population. Using an updated Berman and Crump dose-response model for asbestos exposure, the authors selected population-specific potency factors for lung cancer and mesothelioma. These factors were evaluated on the basis of population-specific cancer data attributed to the studied area's past environmental levels of asbestos. they also used more recent population-specific mortality data along with the validated potency factors to generate corresponding inhalation unit risks. These unit risks were then combined with recent environmental measurements made in the mining town to calculate estimated lifetime risk of asbestos-induced lung cancer and mesothelioma. Depending on the chosen potency factors, the lifetime mortality risks varied between 0.7(best estimate) and 2.6(upper bound) per 100,000 for lung cancer, and between 0.7 and 2.3 per 100,000 for mesothelioma.
The authors concluded that the estimated lifetime cancer risk for both cancers combined is close to Health Canada's threshold for "negligible" lifetime cancer risks.
Crit Rev Toxicol, 2013; 43(2): 154-183 (Open Access)
David Bernstein, Jacques Dunnigan, Thomas Hesterberg, Robert Brown, Juan Antonio Legaspi Velasco, Raul Barrera, John Hoskins, and Allen Gibbs (OPEN ACCESS)
Abstract : This review provides a basis for substantiating both kinetically and pathologically the differences between chrysotile and amphibole asbestos. Chrysotile, which is rapidly attacked by the acid environment of the macrophage, falls apart in the lung into short fibers and particles, while the amphibole asbestos persist creating a response to the fibrous structure of this mineral. Inhalation toxicity studies of chrysotile at non-lung overload conditions demonstrate that the long (>20µm} fibers are rapidly cleared from the lung, are not translocated to the pleural cavity and do not initiate fibrogenic response. In contrast, long amphibole asbestos fibers persist, are quickly (within 7d} translocated to the pleural cavity and result in interstitial fibrosis and pleural inflammation. Quantitative reviews of epidemiological studies of mineral fibers have determined the potency of chrysotile and amphibole asbestos for causing lung cancer and mesothelioma in relation to fiber type and have also differentiated between these two minerals. These studies have been reviewed in light of the frequent use of amphibole asbestos. As with other respirable particulates, there is evidence that heavy and prolonged exposure to chrysotile can produce lung cancer. The importance of the present and other similar reviews is that the studies they report show that low exposures to chrysotile do not present a detectable risk to health. Since total dose over time decides the likelihood of disease occurrence and progression, they also suggest that the risk of an adverse outcome may be low with even high exposures experienced over a short duration.
(Accepted 2 March 2013)
Available online : www.cancerepidemiology.net
J. Schüz a,*, S.J. Schonfeld a, H. Kromhout b, K. Straif c, S.V. Kashanskiy d, E.V. Kovalevskiy e, I.V. Bukhtiyarov e, V. McCormack a
a Section of Environment and Radiation, International Agency for Research on Cancer, Lyon, France
b Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
c Section of IARC Monographs, International Agency for Research on Cancer, Lyon, France
d Yekaterinburg Medical Research Center for Prophylaxis and Health Protection in Industrial Workers, Yekaterinburg, Russian Federation
e Scientific Research Institute of Occupational Health of the Russian Academy of Medical Sciences, Moscow, Russian Federation
The authors from France, the Netherlands and Russia have begun fieldwork on a retrospective cohort study of employees of one of the world’s largest chrysotile mine and mills, situated in Asbest, Russia. The primary aim of the study is to better characterize and quantify the risk of cancer mortality in terms of (i) the dose - response relationship of exposure with risk; (ii) the range of cancer sites affected, including female - specific cancers; and (iii) effects of duration of exposure and latency periods. This information will should help in understanding of the scale of the impending cancer burden due to chrysotile, including if chrysotile use ceased worldwide forthwith. In this publication, the authors describe the scientific rationale for conducting this study and the main features of its study design.
J. Hazard. Mater. 252-253, 390-400 (2013)
Martin Radvanec; Lubomír Tuček; Ján Derco; Katarína Cechovská; Zoltán Németh
This article presents a procedure and experimental results of artificial carbonatization, applied in to asbestos cement (eternit). The wet crushed and pulverized asbestos cement is first thermally modified at 650°C. Then the chrysotile fibers are easily and completely reacted with a mixture of CO2 and water, producing new Mg-rich carbonates - hydromagnesite and magnesite: Applying this methodology, the asbestos-bearing waste can be stabilized and environmentally friendly permanently deposited. This procedure may be a way of neutralizing of extreme pH values (around 12) at large eternit dumps. Simultaneously, the artificial carbonatization of chrysotile asbestos by applying CO2 offers an alternative way for permanent elimination of a part of industrial CO2 emissions, thus contributing to multiple benefits of this methodology.
Recent Results Cancer Res. 189, 79 (2011)
Volker Neumann; Stefan Löseke; Andrea Tannapfel. German Mesothelioma Register, University Hospital Bergmannsheil, Bochum, Germany. email@example.com
A study was conducted at the German Mesothelioma Registry in Bochum, Germany on the relationship between mesothelioma and asbestos exposure. The study was based on the fact that mineral analysis of lung tissue can provide valuable information for the research of asbestos-related diseases and for assessment of exposure.
Their analysis of lung tissue for asbestos burden led the authors to state that « The predominant fiber-type identified by electron microscopy in patients with mesothelioma is amphibole asbestos (crocidolite or amosite). »
This review provides a basis for substantiating both kinetically and pathologically the differences between chrysotile and amphibole asbestos. Chrysotile, which is rapidly attacked by the acid environment of the macrophage, falls apart in the lung into short fibers and particles, while the amphibole asbestos persist creating a response to the fibrous structure of this mineral. Inhalation toxicity studies of chrysotile at non-lung overload conditions demonstrate that the long (420 mm) fibers are rapidly cleared from the lung, are not translocated to the pleural cavity and do not initiate fibrogenic response. In contrast, long amphibole asbestos fibers persist, are quickly (within 7 d) translocated to the pleural cavity and result in interstitial fibrosis and pleural inflammation. Quantitative reviews of epidemiological studies of mineral fibers have determined the potency of chrysotile and amphibole asbestos for causing lung cancer and mesothelioma in relation to fiber type and have also differentiated between these two minerals. These studies have been reviewed in light of the frequent use of amphibole asbestos. As with other respirable particulates, there is evidence that heavy and prolonged exposure to chrysotile can produce lung cancer. The importance of the present and other similar reviews is that the studies they report show that low exposures to chrysotile do not present a detectable risk to health. Since total dose over time decides the likelihood of disease occurrence and progression, they also suggest that the risk of an adverse outcome may be low with even high exposures experienced over a short duration.
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David M. Bernstein, Ph.D
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Occupational exposure to relatively pure chrysotile within permissible levels was not associated with a significant increase in lung cancer or with mesothelioma. Decreased overall mortality of workers indicates a healthy worker effect, which – together with the relatively small cohort size – could have prevented small risks to e detected.
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A careful examination of studies shows that this statement is grossly misleading and represents only selective parts of the scientific info.
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Are Perceptions Related to FACTS?
This document is a rapid overview of the recent scientific studies that support a controlled approach for the use of chrysotile and puts in perspective the pitfalls of over regulation.
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Why so much emotion?
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IBE - Opinion Paper
Asbestos on the carcinogenic substances list
Scientists re-establish facts
The health effects of chrysotile: Current perspective based upon recent data
David M. Bernstein, John A. Hoskins
Chrysotile as a Cause of Mesothelioma: An Assessment Based on Epidemiology
Charles M. Yarborough, Exponent, Inc., New York, New York, USA
The Toxicological Response of Brazilian Chrysotile Asbestos: A Multidose Subchronic 90-Day Inhalation Toxicology Study with 92-Day Recovery to Assess Cellular and Pathological Response
By: David M. Bernstein, Rick Rogers, Paul Smith, Jörg Chevalier
Inhalation Toxicology, Second Edition
By: David M. Bernstein
An Exposure Study of Bystanders and Workers During the Installation and Removal of Asbestos Gaskets and Packing
by: Carl Mangold, Katherine Clark, Amy Madl and Dennis Paustenbach
CASITILE, THE NEW ASBESTOS: Time to clear the air and save £20 billion
By: Professor John Bridle and Sophie Stone MSc BSc (Hons)
Understanding Chrysotile Asbestos: A New perspective Based upon Current Data
By: David M. Bernstein
The toxicological response of Brazilian chrysotile asbestos : A multi-dose sub-chronic 90-day inhalation toxicology study with 92 day recovery to assess cellular and pathological response.
By: David M. Bernstein
Alarm rising in Denmark over plastic piping
Environment Daily 1395, 28/02/03
Special Report: Asbestos-Cement Pipe
Chrysotile Asbestos-Cement (a/c) pipe has been used in water distribution systems around the world for more than 70 years. More than 2.5 million kilometres of a/c pipe are in use world wide. As this Special Report demonstrates, a/c pipe is cost effective, energy efficient, durable and safe.
This Special Report takes a look at some of the key studies conducted over the last 30 years and reviews the evidence relating to the nature of mesothelioma risks, their association with exposure to the different asbestos fibres, as well as findings that a significant percentage of cases appear to be unrelated to asbestos exposure.