Thesis--Wisconsin. / Includes bibliographical references (leaves 94-97).

Orientador: Ines Joekes / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-07-26T15:05:12Z (GMT). No. of bitstreams: 1 Fachini_Adriano_D.pdf: 4058425 bytes, checksum: e946502c182bf056a8f070ada17bcbc3 (MD5) Previous issue date: 1999 / Doutorado

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The purpose of this study was to determine the factors affecting the acid degradation of chrysotile asbestos (Mg_3Si_2O_5(OH_4)) . Millions of tons of asbestos have found use in this country as insulative or ablative material. More than 95 percent of the asbestos in use is of the chrysotile variety. The remaining 5 percent is composed of various types of fibrous amphiboles. The inhalation of asbestos can lead to several diseases in humans. Asbestosis, lung cancer and mesothelioma are the most common afflictions associated with asbestos inhalation, and they may occur up to 40 years after the initial exposure. It has previously been reported that if more than 50 percent of the magnesium is removed from a chrysotile sample its carcinogenicity is reduced to nil. Several inorganic acids were studied to determine their ability to leach magnesium from chrysotile. It was found that the ability to leach magnesium was dependent upon the acidic anion in addition to the concentration of the acid. The ordering of the efficiency of the acids in their ability to remove magnesium from chrysotile was found to be HCl > H_2SO_4 > H_3PO_4 > HNO_3. Predictive equations were developed to allow the calculation of the amount of magnesium removed under various acid concentrations as a function of time and acid species. The effects of temperature and dissolved spectator cations upon the degradation process were also examined. There was no major effect on the amount of magnesium removed as a function of spectator cation concentration. An infrared method was also developed to allow the determination of the percent degradation of a chrysotile sample directly. The shifts in the positions of three silicate stretching peaks (1068 cm^-1, 948 cm^-1 and 715 cm^-1) and one magnesium oxygen stretching peak (415 cm"1) as a function of the percent magnesium removed were correlated to allow this determination.

A review of the literature relating to the diseases associated with exposure to asbestos is followed by a description of processes involving materials containing asbestos, and the men employed, in HJ Dockyard, Devonport. The development of preventive measures is explained, and details are given of the precautionary methods which have been introduced as a direct result of the present survey. An account is presented of an extensive survey of the dust concentrations occurring in most of the processes involving asbestos materials in the Dockyard. This survey shows the degree of risk to which men have probably been exposed in the past, and explains how many men, not previously thought to have been at risk, have been exposed to high dust concentrations. A detailed study of the clinical, radiological and physiological changes occurring in the men exposed to asbestos is described, and this is followed by a proportional mortality study of the lung and gastro-intestinal neoplasms occurring in Plymouth males. The report concludes with a general discussion of. the data.

Thesis (Ph.D. (Geography)(GIS and remote sensing)) --University of Limpopo, 2009 / Mining of the environment leaves scars of environmental damage and associated health consequences resulting from exploration, extraction and processing of minerals. These impacts tend to get worse during the post closure period on the abandoned derelict mines. The South African government is conducting environmental remediation on the mines which were abandoned by colonial mining companies. In this situation, monitoring and evaluation of such projects becomes a necessity to ensure sustainability of the mine rehabilitation process. However, the government did not have any plan and/or capacity to monitor the rehabilitation process. This study therefore utilizes remote sensing techniques to monitor the asbestos mine rehabilitation process at Mafefe and Mathabatha and to assess its effectiveness as short and long term strategies of environmental management. This research used Landsat Thematic Mapper (TM) images (1989 - 2004) to assess and monitor mine degradation and rehabilitation efforts in the study area. Two scenes were acquired for each year, representing both low peak and high peak growing periods. An image differencing method (NDVI) was used to assess the condition of vegetation in the study area.Results showed both positive and negative trends in vegetation growth. In order to understand the dynamics depicted from satellite images in the post mining phase, a field campaign was conducted to understand the reflective properties of the variables (vegetation species) used for mine rehabilitation. Results using leaf area index (LAI) and fraction of photosynthetically active radiation (fPAR) provides a proper reasoning for the type of positive environmental change reflected from satellite images. This therefore makes remote sensing an important tool for the limited field monitoring capacity for observing the dynamics of mining environments in the post closure phase. The image differencing method also helped in identifying areas that needs further rehabilitation.Despite the rehabilitation efforts, field evidence shows that traces of different asbestos minerals appear scattered even after the rehabilitation process has been conducted. This has not been properly reported since there was no effectively coordinated monitoring procedure in place to assess the progress of mine rehabilitation in mitigating asbestos pollution. This study therefore used in situ remote sensing techniques to spectrally differentiate various types of asbestos minerals with the aim of determining its potential in assessing asbestos pollution.Data generated from an X-Ray Diffraction and Scanning Electron Microscopy were also utilized for the identification and characterization of asbestos minerals in soil and water of the rehabilitated environments which were also examined using in situ remote sensing. An Analytical Spectral Devices (ASD) Field Spectrometer was used to collect spectra of asbestos minerals and that of soil and water samples for comparative analysis with laboratory results. Results showed that in situ remote sensing can play a significant role in monitoring the distribution of the asbestos minerals over rehabilitated surface areas. However, the spectral characteristics of asbestos minerals in the water bodies were not conclusive enough when compared to laboratory methods.Within the context of South Africa as a developing country, remote sensing is recommended as an important tool for periodic assessment and monitoring of mine rehabilitation. This will fill the gap created from the limited capacity within the government for monitoring and evaluation of asbestos mine rehabilitation. It is also the most cost effective method of conducting natural resource monitoring. / Department of Science and Technology, the CSIR SAC, University of Stellenbosch, and the Agricultural Research Council-Institute for soil, climate and water

The asbestos resources in Turkey should be exploited in a carefully planned manner for two reasons: (1) to minimize the health hazards associated with the mining and processing of asbestos, and (2) to avoid wasteful exploitation for the sake of making profit. Its consumption should be optimized by using it for the critical applications only, where its unique properties are essential. Turkey's asbestos resources and alternative minerals to asbestos should be exploited to assist in its economic development. However Turkey must control the environmental and occupational hazards associated with the production of these commodities if it is to avoid the loss experience of other developed countries. The hazards associated with the use of asbestos in many noncritical applications have raised the demands for substitute materials which are less hazardous. Turkey is in a position of developing and marketing many of the substitute materials by exploiting some of its industrial minerals.

Current methods for the detection and quantitation of airborne asbestos are either tedious, time consuming, subjective, or too expensive for routine analysis. A FT-IR spectroscopic method for the identification and quantitation of airborne asbestos samples provides a relatively inexpensive, fast, and non-subjective alternative for routine analysis.Three methods are investigated for the separation of the asbestos fibers from the matrix of the collection filter, (a mixed cellulose ester) for infrared analysis: spectral subtraction, chemical digestion, and ashing. Problems associated with the handling of asbestos (sample loss and contamination), and band anomalies encountered during spectral subtractions are discussed.Calibration curves are presented using the asbestos Si-O absorptions to quantitate the amount of asbestos. The spectral subtraction method yields linear calibration curves down to 0.3% asbestos by weight (6 mg) for tremolite asbestos. Tremolite and amosite asbestos calibration curves are linear down to 8 µg and 3 µg asbestos respectively using the ashing method.The spectral subtraction method and the ashing method are applied to NIOSH prepared PAT samples previously analyzed by phase contrast microscopy.The spectra are analyzed for asbestos by band identity, and once identified, quantitated from the appropriate calibration curve. / Department of Chemistry

The dimensions of airborne fibres collected at various stages of fibre processing in mines and mills producing crocidolite, amosite and chrysotile asbestos were measured by using light optical and electron microscopy. Airborne fibres of different asbestos types had markedly different size and shape distributions. For a given asbestos type, airborne fibres collected at various stages of processing differed in their size distributions but the differences were considerably less than between fibre types. Most of the airborne fibres to which miners and millers were exposed were short, thin and thus respirable. The proportions of long fibres in the air of crocidolite and chrysotile mines and mills were small compared to those in amosite mining and milling environments. The physical parameters which best differentiated crocidolite fibres from other asbestos fibre types were aspect ratio, which was higher, and proportions of long thin fibres (0.06 - 0.2 (mu)m in diameter and > 5 (mu)m in length). Median mass of amosite fibres was more than 108 and 13 times higher than the median mass of chrysotile and crocidolite fibres respectively. Median true diameter of amosite fibres was approximately 4 and 3 times higher than median true diameters of chrysotile and crocidolite fibres respectively. Median true length of amosite fibres was more than 4.5 and 1.9 times higher than median true lengths of chrysotile and crocidolite fibres respectively. / The differences in size and shape of airborne fibres have important implications for setting of work environmental standards and explaining differences in health risks associated with different fibre types.