Acute health effects of a fire associated with asbestos-containing fallout.
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BACKGROUND: In September 1994 in a disused leather factory in Tranmere, Wirral, England, there was a fire associated with asbestos-containing fallout in an urban area. This study aimed to describe the acute health effects of this acute environmental incident. METHODS: Descriptive epidemiology of acute health effects of the fire was based on solicitors' letters from compensation claimants, hospital admissions for asthma and other respiratory diseases, accident and emergency records, occupational health records of fire-fighters and police, reports of cases by general practitioners (GPs), and geographical location of calls for help and claimants. RESULTS: Sixteen thousand people lived in the area worst affected by fallout. There were 344 claimants. Eighty-six per cent of claimants had a health complaint, with a total of 728 symptoms or diseases reported to be a consequence of the fire. Seventy per cent of complaints related to the respiratory tract, with 33 per cent of claimants noting sore throat, 31 per cent cough, 9 per cent exacerbated asthma, 8 per cent breathing problems and 13 per cent headaches. The number of hospital admissions for asthma and other lung diseases 1 day, 2 days, 7 days and 28 days after the date of the incident tended to be lower in the year of the fire than in other years. Within 72 h of the fire no cases connected with the fire were seen in the local accident and emergency unit. The geographical location of calls for help to the environmental health department was different from that for compensation claimants. CONCLUSIONS: Hundreds of people sought compensation for the acute health consequences of the fire. Many symptoms or diseases in 344 people were attributed to the fire, but there is no hard evidence to suggest that these were directly due to the fire, although some may have been indirectly attributable to it. (+info)
The quantitative risks of mesothelioma and lung cancer in relation to asbestos exposure.
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Mortality reports on asbestos exposed cohorts which gave information on exposure levels from which (as a minimum) a cohort average cumulative exposure could be estimated were reviewed. At exposure levels seen in occupational cohorts it is concluded that the exposure specific risk of mesothelioma from the three principal commercial asbestos types is broadly in the ratio 1:100:500 for chrysotile, amosite and crocidolite respectively. For lung cancer the conclusions are less clear cut. Cohorts exposed only to crocidolite or amosite record similar exposure specific risk levels (around 5% excess lung cancer per f/ml.yr); but chrysotile exposed cohorts show a less consistent picture, with a clear discrepancy between the mortality experience of a cohort of xhrysotile textile workers in Carolina and the Quebec miners cohort. Taking account of the excess risk recorded by cohorts with mixed fibre exposures (generally<1%), the Carolina experience looks uptypically high. It is suggested that a best estimate lung cancer risk for chrysotile alone would be 0.1%, with a highest reasonable estimate of 0.5%. The risk differential between chrysotile and the two amphibole fibres for lunc cancer is thus between 1:10 and 1:50. Examination of the inter-study dose response relationship for the amphibole fibres suggests a non-linear relationship for all three cancer endpoints (pleural and peritoneal mesotheliomas, and lung cancer). The peritoneal mesothelioma risk is proportional to the square of cumulative exposure, lung cancer risk lies between a linear and square relationship and pleural mesothelioma seems to rise less than linearly with cumulative dose. Although these non-linear relationships provide a best fit ot the data, statistical and other uncertainties mean that a linear relationship remains arguable for pleural and lung tumours (but not or peritoneal tumours). Based on these considerations, and a discussion fo the associated uncertainties, a series of quantified risk summary statements for different elvels of cumulative exposure are presented. (+info)
Increased expression of epidermal growth factor receptor in rat pleural mesothelial cells correlates with carcinogenicity of mineral fibres.
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Asbestos fibres have been shown to stimulate the mitogen-activated protein kinase signalling cascade in rat pleural mesothelial (RPM) cells after autophosphorylation of the epidermal growth factor receptor (EGFR). We examined if mineral fibres with known carcinogenicity can be discriminated from materials with less or no carcinogenicity by their ability to up-regulate expression of EGFR protein in RPM cells in vitro. Crocidolite and erionite, two fibrous preparations with marked potential to induce mesothelioma, were associated with increases in EGFR protein expression over sham controls, whereas chrysotile asbestos and milled (non-fibrous) crocidolite did not. Intense patterns of EGFR protein expression were linked to RPM cells phagocytosing long fibres. To determine the role of EGFR expression in these cells, we assessed cell proliferation using an antibody against proliferating cell nuclear antigen (PCNA) in combination with an antibody against EGFR. In these co-localization studies, cells showed intense staining for EGFR protein 24 h before being PCNA positive at 48 h. These results suggest that carcinogenic fibres induce EGFR and initiate cell signalling cascades in mesothelial cells, leading to cell proliferation and carcinogenesis. (+info)
Amphibole fibres in Chinese chrysotile asbestos.
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Ten chrysotile bulk samples originating from six Chinese chrysotile mines were studied for amphibole fibres. Five of the mines operate on ultramafic rocks whereas one exploits a dolomite-hosted deposit. The asbestos fibre content in lung tissue was examined from seven deceased workers of the Shenyang asbestos plant using these raw materials. The bulk samples were pretreated with acid/alkali-digestion, and thereafter, scanning and transmission electron microscopy, X-ray microanalysis, selected area electron diffraction and X-ray powder diffractometry were used to identify the minerals. Sample preparation of lung tissue involved drying and low-temperature ashing. All of the bulk samples contained amphibole fibres as an impurity. The amphibole asbestos contents were between 0.002 and 0.310 w-%. Tremolite fibres were detected in every sample but anthophyllite fibres were present only in the sample originating from the dolomite-hosted deposit. In comparison, anthophyllite (71%), tremolite (9%) and chrysotile (10%) were the main fibre types in the lung tissue samples indicating faster pulmonary clearance of chrysotile fibres. The total levels ranged from 2.4 to 148.3 million fibres (over 1 microm in length) per gram of dry tissue, and they were consistent with heavy occupational exposure to asbestos. (+info)
Man-made respirable-sized organic fibers: what do we know about their toxicological profiles?
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Man-made organic fibers (MMOFs) have been manufactured for over 50 years. Until recently, there have been few concerns raised regarding the safety of organic fiber dusts. This is due, in large part, to the perception that the dimensions of most, if not all, of these products were too large to be inhaled into the distal lungs of workers, i.e., were considered to be nonrespirable. A brief review of some of the issues related to organic fiber toxicology is presented herein. Some of the organic fiber-types used in commerce are identified and some fundamental tenets of fiber toxicology are discussed. In addition, the European Union, in their recent consideration for banning chrysotile asbestos fibers, evaluated some organic fiber substitutes and compared them to the hazards of asbestos. A brief review of their conclusions is described below. Finally, the results of some recent studies assessing the mechanisms of biodegradability of para-aramid respirable-sized, fiber-shaped particulates (RFP) are presented. Para-aramid (p-aramid) RFP are the most extensively-studied respirable organic fiber-type and RFP is the new term which describes respirable-sized organic fibers (ECETOC, 1996) (1). The results of these studies provide clues regarding the mechanism(s) of p-aramid RFP shortening in the lungs of exposed animals, and may be relevant for humans. (+info)
Airborne fiber concentration and size distribution of mineral fibers in area with serpentinite outcrops in Aichi prefecture, Japan.
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Airborne fiber concentrations and size distributions of both asbestos and nonasbestos fibers were determined at property boundaries of 4 serpentinite quarries producing crushed stone (quarry property boundary), 10 sites within 10 km of the area with serpentinite outcrops (serpentinite area), and 2 sites in a reference area. The asbestos was identified in 7 rock and 3 soil samples collected in the serpentinite area. The geometric means of airborne concentrations of asbestos and nonasbestos fibers longer than 0.2 microm in length were: 384 and 447 fibers/liter (f/L) in the quarry property boundary (in operation), 12 and 124 f/L in the quarry property boundary (in closed), 5 and 103 fibers/liter in the serpentinite area, and less than 2 and 59 fibers/liter in the reference area, respectively. There was a significant difference in airborne concentrations of both asbestos and nonasbestos fibers among the areas. Ttremolite/actinolite were found with chrysotile in the stones. Airborne concentrations of tremolite/actinolite were higher than those of chrysotile at the quarry property boundary and in the serpentinite area. Tremolite/actinolite were also found in the soils. There was no significant difference among the areas in the arithmetic means of fiber size distribution of both asbestos and nonasbestos fibers. (+info)
Retrospective view of airborne dust levels in workplace of a chrysotile mine in Ural, Russia.
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The Bazhenovskoye chrysotile asbestos deposit has been exploited for 115 years. All the technological operations in the quarry are accompanied by the formation of high-dispersion asbestos-containing aerosols. The dust concentrations at the miner's working places for the last 30 years (1970-2000) were at or below the Russian MACs(m.s.) level (4.0 mg/m3). The seasonal precipitation amount in the deposit area causes a rise in dust content in certain periods. The maximum density of asbestos respirable fibres exceeded 2.7 f/cm3. All the identified fibres belonged to chrysotile asbestos, and no amphibole asbestos, such as tremolite asbestos, has been identified. An excessive dust level remains, despite the dust content level decrease, at the work sites of oversized lump drillers and unloaders, and oncopathology heightened risk remains in these occupational groups, as a result. (+info)
The carcinogenicity of chrysotile asbestos--a review.
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The world production of asbestos has been declining dramatically in recent years, particularly in Europe and the United States. However, increases have occurred in Asian nations and chrysotile is the dominant fiber used. Important uses are in cement products, wallboards, friction products and textiles. From studies in the United States and Great Britain, chrysotile has been shown to increase the risk of lung cancer and to produce mesothelioma in exposed workers. (+info)