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PubMed1997

Coal mine workers' pneumoconiosis (CWP): in vitro study of the release of organic compounds from coal mine dust in the presence of physiological fluids.

Solvents like dichloromethane generally are used to yield exhausted extraction amounts of the organic compounds in coals. Leaching of coal mine dust by dichloromethane yields extracts with comparable amounts of alkanes, aromatics, and phenolic compounds. Dominantly phenolic compounds are leached from coal mine dust by aqueous solutions saturated in lecithin because of their high water solubility. High concentrations of phenolic compounds can be extracted from coal mine dust generated from low-rank coals. Phenolic compounds leached by fluids adapted to physiological conditions correlate with high cytotoxicities of the dust from low-rank coals. Adaptation of leaching fluids to physiological conditions allows a more realistic estimation of experiments. Coal mine dust with varying coal content of different ranks can be seen as a parameter reinforcing the cytotoxic potential of coal mine dust.

Body Fluids↗
PubMed1979

Health and environmental impacts of increased generation of coal ash and FGD sludges. Report to the Committee on Health and Ecological Effects of Increased Coal Utilization.

This paper focuses on the incremental impacts of coal ash and flue gas desulfurization (FGD) wastes associated with increased coal usage by utilities and industry under the National Energy Plan (NEP). In the paper, 1985 and 2000 are the assessment points using the baseline data taken from the Annual Environmental Analysis Report (AEAR, September 1977). In each EPA region, the potential mix of disposal options has been broadly estimated and impacts assessed therefrom. In addition, future use of advanced combustion techniques has been taken into account. The quantities of coal ash and FGD wastes depend on ash and sulfur content of the coal, emission regulations, the types of ash collection and FGD systems, and operating conditions of the systems and boiler. The disposal of these wastes is (or will be) subject to Federal and State regulations. The one key legal framework concerning environmental impact on land is the Resource Conservation and Recovery Act (RCRA). RCRA and related Federal and State laws provide a sufficient statutory basis for preventing significant adverse health and environmental impacts from coal ash and FGD waste disposal. However, much of the development and implementation of specific regulations lie ahead. FGD wastes and coal ash and FGD wastes are currently disposed of exclusively on land. The most common land disposal methods are inpoundments (ponds) and landfills, although some mine disposal is also practiced. The potential environmental impacts of this disposal are dependent on the characteristics of the disposal site, characteristics of the coal ash and FGD wastes, control method and the degree of control employed. In general, the major potential impacts are ground and surface water contamination and the "degradation" of large quantities of land. However, assuming land is available for disposal of these wastes, control technology exists for environmentally sound disposal. Because of existing increases in coal use, the possibility of significant environmental impacts, both regionally and nationally, exists regardless of whether the NEP scenario develops or not. Existing baseline data indicate that with sound control technology and successful development and implementation of existing regulatory framework, regional scale impacts are likely to be small; however, site-specific impacts could be significant and need to be evaluated on a case-by-case basis. Both Federal and privately-funded programs are developing additional data and information on disposal of FGD sludges and coal ash. Continuation of these programs will provide additional vital information in the future. However, further information in several areas if desirable: further data on levels of radionuclides and trace metals in these wastes: studies on biological impacts of trace metals; and completion of current and planned studies on disposal problems associated with advanced combustion techniques like fluid bed combustion.

Coal↗
PubMed2002

Mineral matter distribution on coal surface and its effect on coal wettability.

Coal is an organic sedimentary rock composed of organic macerals and mineral matter. As it is demonstrated in this paper the discrete mineralogical nature of coal largely influences the wetting of the coal surface by water. Both advancing and receding contact angles were measured using the captive-bubble technique with an automatic bubble shape analysis software. The distribution and amount of mineral inclusions on the coal surface were determined by scanning electron microscopy and examined using the image analysis system. To determine the amount and size distribution of mineral grains, the coal surface layer, on which the contact angles were measured, was separated from the larger piece used in the measurements by microslicing. The separated surface layer was subjected to a low-temperature ashing followed by particle size analysis. As expected, a significant scatter of contact angle values was obtained for the same coal samples. Increasing the amount of mineral matter on the coal surface reduced the value of both advancing and receding contact angles. Also, the scatter of contact angle values increased with the increasing mineral matter content from about 1 to 50 wt%. The results reveal that an important factor in analysis of contact angle variation on coal surfaces is the size of the hydrophilic mineral inclusions. Both the advancing and the receding contact angles decrease with increasing size of the mineral grains. Additionally, the scatter of contact angle values increase with increasing size of the mineral matter grains. Finally, the results of fractal dimension analysis of mineral matter grains distributed over the coal surface indicate that there is no significant effect from the shape of hydrophilic mineral inclusions on both advancing and receding contact angles.

Journal Article↗
PubMed2005

Effect of microwave pretreatment of coal for improvement of rheological characteristics of coal-water slurries.

Indian high-ash coal contains alpha-silica components of the mineral matter. When coal is transported in the form of a slurry, alpha-silica adds to the settling properties of coal and enhances erosion of pipelines. As such any technique that will contribute to changing the characteristics of mineral matter by selective demineralization is bound to supplement the knowledge of coal slurries in the science of rheology. One such method is the use of a novel microwave technology, which changes the alpha-silica to less harmful beta-silica. Thus microwave-treated coal slurry facilitates enhanced flow characteristics and abates the erosion problem in pipeline transport as well as in coal-slurry injection furnaces. This paper reports on the rheological study of closely sized coal particles of medium-volatile, low-ash, low-moisture cleans and high-ash rejects with and without microwave treatment. Viscosity of suspensions of microwave-treated coal was found to be less than that of untreated coal, in the case of both cleans and rejects. Microwave pretreatment thus reduces the viscosity and the pumping cost and opens a new outlook for pipeline transport. An attempt has been made to quantify the improvement of rheological characteristics due to microwave pretreatment.

Journal Article↗
PubMed1987

Microbially mediated leaching of low-sulfur coal in experimental coal columns.

The leaching of a low-sulfur bituminous coal was investigated with experimental coal columns subjected to simulated rainfall events. Leachates from the columns became dominated by iron-oxidizing bacteria as evidenced by specific enrichment cultures and measurements of CO(2) assimilation. Heterotrophic microorganisms were also present in the coal leachates, but their numbers and activity decreased with decreasing pH. This pattern could be reversed by increasing the pH of the coal with lime. Organosulfur-utilizing bacteria made up a substantial portion of the heterotrophic community. Measurements of microbial activity in coal cores indicated that although much of the microbial community remained associated with coal particles, the relative abundance of heterotrophs and autotrophs in leachate seemed to reflect that in coal cores. When bacterial growth was delayed by autoclaving coal samples, acid production and leaching of iron and sulfur were also delayed. Rapid leaching of materials from coal thus appears to be strongly dependent on the presence of the natural bacterial microflora.

Journal Article↗
PubMed1980

Report of health and environmental effects of increased coal utilization by the Committee on Health and Environmental Effects of Increased Coal Utilization.

The National Energy Plan announced by President Carter on April 29, 1977 proposed a significant increase in the utilization of the vast domestic deposits of coal to replace the dwindling supplies of oil and natural gas, and increasingly expensive oil from foreign sources, to meet national energy needs. At the same time, in recognition of possible adverse health and ecological consequences of increased coal production and use, the President announced that a special committee would be formed to study this aspect of the National Energy Plan. The Committee held a series of public meetings during November and December 1977 to review a number of special papers on particular problems associated with increased coal utilization. These papers, which were prepared by scientists of the US Environmental Protection Agency; the Department of Energy; the HEW National Institute for Occupational Safety and Health, and the National Institute of Environmental Health Sciences; New York University; and Vanderbilt University; provided essential background information for the deliberations of the Committee and were published in EHP Vol. 33, pp. 127-314, 1979. One paper by A. P. Altschuler et al. is published in this volume of EHP. The Committee's basic finding was that it is safe to proceed with plans to increase the utilization of coal if the following environmental and safety policies are adhered to:* Compliance with Federal and State air, water, and solid waste regulations* Universal adoption and successful operation of best available control technology on new facilities* Compliance with reclamation standards* Compliance with mine health and safety standards* Judicious siting of coal-fired facilitiesThe Committee concluded that, even with the best mitigation policies, there will be some adverse health and environmental effects from the dramatic increase in coal use. However, these will not impact all regions and individuals uniformly. The Committee identified six major areas of uncertainty and concern requiring further investigation if the nation is to minimize undesirable consequences of increased coal utilization now, and in the future. Two critical health issues of concern are air pollution health effects and coal mine worker health and safety. Two critical environmental issues are global effects of carbon dioxide in the atmosphere and acid fallout. Two additional important issues of concern are trace elements in the environment and reclamation of arid land.Finally, because of the inadequate data and methodology used in the study of these matters, the Committee strongly recommended the establishment of an improved national environmental data collection, modeling and monitoring system.

Air Pollutants↗
PubMed1997

Toxicity and occupational health hazards of coal fly ash (CFA). A review of data and comparison to coal mine dust.

Coal fly ashes (CFA) are complex particles of a variable composition, which is mainly dependent on the combustion process, the source of coal and the precipitation technique. Toxic constituents in these particles are considered to be metals, polycyclic aromatic hydrocarbons and silica. The purpose of this review was to study the in vitro and in vivo data on coal fly ash and relate the studied endpoints to the role of (crystalline) silica, considering its recent classification as a human carcinogen. For most of the effects coal mine dust was chosen as a reference, since it contains up to 10% of crystalline silica (alpha-quartz) and is well studied both in vivo and in vitro. Most studies on fly ash toxicity were not designed to elucidate the effect of its silica-content nor did they include coal mine dust as a reference. Taking this into account, both in vitro and in vivo experimental studies show lower toxicity, inflammatory potential and fibrogenicity of CFA compared to silica and coal mine dust. Although in vitro and in vivo studies suggest genotoxic effects of fly ash, the data are limited and do not clarify the role of silica. Epidemiological studies in fly ash exposed working populations have found no evidence for effects commonly seen in coal workers (pneumoconiosis, emphysema) with the exception of airway obstruction at high exposure. In conclusion, the available data suggest that the hazard of coal fly ash is not to be assessed by merely adding the hazards of individual components. A closer investigation of 'matrix' effects on silica's toxicity in general seems an obligatory step in future risk assessment on fly ashes and other particles that incorporate silica as a component.

Animals↗
PubMed2001

Comparative analysis of PAH:DNA adducts formed in lung of mice exposed to neat coal tar and soils contaminated with coal tar.

7H-Benzo[c]fluorene (benzo[c]fluorene) is a major DNA adduct forming component of coal tar in lung of mice. The present study evaluated the types of PAH:DNA adducts formed from different neat coal tar samples and soils contaminated with coal tar. Mice were fed diets containing coal tar either neat or as a contaminant in an environmental soil sample for 14 days, and the types of chemical:DNA adducts formed in lung were evaluated using 32P-postlabeling and HPLC analysis. Three major DNA adducts derived respectively from benzo[b]fluoranthene (B[b]F), benzo[a]pyrene (B[a]P), and benzo[c]fluorene were detected in three of the four neat coal tar samples evaluated. In contrast, only a single major DNA adduct derived from benzo[c]fluorene was observed with the remaining tar sample. Ingestion of coal tar contaminated soil resulted in DNA adducts primarily derived from benzo[c]fluorene and B[b]F; a B[a]P derived DNA adduct was not detected. The DNA adducts derived from benzo[c]fluorene and B[b]F but not B[a]P were also observed with animals fed methylene chloride extracts of three of these soils but not the one designated A1000H soil. However, the extract of A1000H resulted in a B[a]P:DNA adduct being detected along with adducts formed from B[b]F and benzo[c]fluorene. The selective formation of the benzo[c]fluorene:DNA adduct with coal tar contaminated soils indicates that the in vivo systemic bioavailability and/or metabolism of benzo[c]fluorene is relatively high when compared to other DNA adducting hydrocarbons within coal tar. Benzo[c]fluorene may play a critical role in the potential of contaminated soil to induce a toxicological response in animals.

Administration, Oral↗
PubMed2001

Monitoring the species of arsenic, chromium and nickel in milled coal, bottom ash and fly ash from a pulverized coal-fired power plant in western Canada.

The concentration of As, Cr and Ni and their speciation (As3+;5+, Cr3+;6+ and Ni0;2+) in milled coal, bottom ash and ash collected by electrostatic precipitator (ESP) from a coal fired-power plant in western Canada were determined using HGAAS, ICP-AES and XANES. The chemical fractionation of these elements was also determined by a sequential leaching procedure, using deionized water, NH4OAC and HCI as extracting agents. The leachate was analyzed by ICP-AES. Arsenic in the milled coal is mostly associated with organic matter, and 67% of this arsenic is removed by ammonium acetate. This element is totally removed from milled coal after extraction with HCI. Arsenic occurs in both the As3+ and the As5+ oxidation states in the milled coal, while virtually all (>90%) of the arsenic in bottom ash and fly ash appears to be in the less toxic arsenate (As5+) form. Both Ni and Cr in the milled coal are extracted by HCI, indicating that water can mobilize Ni and Cr in an acidic environment. The chromium is leached by water from fly ash as a result of the high pH of the water, which is induced during the leaching. Ammonium acetate removes Ni from bottom ash through an ion exchange process. Chromium in milled coal is present entirely as Cr3+, which is an essential human trace nutrient. The Cr speciation in bottom ash is a more accentuated version of the milled coal and consists mostly of the Cr3+ species. Chromium in fly ash is mostly Cr3+, with significant contamination by stainless-steel from the installation itself.

Air Pollution↗
PubMed1990

Contrasting bronchoalveolar leukocyte responses in rats inhaling coal mine dust, quartz, or titanium dioxide: effects of coal rank, airborne mass concentration, and cessation of exposure.

The aim of this study was to determine the bronchoalveolar leukocyte response to airborne coal mine dust; quartz and titanium dioxide were used as positive and negative controls, respectively. Groups of rats were exposed to airborne mass concentrations of 10 and 50 mg/m3 of the dusts for 7 hr/day, 5 days/week and their bronchoalveolar space was lavaged at time points between 2 and 75 days of exposure, to assess the leukocyte response. This study revealed time-dependent and airborne mass concentration-dependent recruitment of neutrophils and macrophages into the bronchoalveolar region with coal mine dust inhalation but no real difference in the magnitude of the response between coal mine dusts from collieries mining coal of different rank and quartz content although the maximum quartz content in the dusts used was 6%. The inflammatory response was much less than that produced by quartz, at similar airborne mass concentrations, and more than that produced by titanium dioxide which was, in general, a poor inflammogen in the rat lung. Groups of rats were exposed to the airborne dusts for 32 or 75 days, then removed from the exposure chambers, and allowed to recover by breathing room air for a further 64 days. During this recovery period there was marked progression of the leukocyte response with quartz and persistence of the response with coal mine dust. Chronic recruitment of leukocytes to the lungs of individuals inhaling coal mine dust is likely to be an important factor in the development of coal workers' pneumoconiosis.

Administration, Inhalation↗
PubMed2001

Boiler briquette coal versus raw coal: Part II--Energy, greenhouse gas, and air quality implications.

The objective of this paper is to conduct an integrated analysis of the energy, greenhouse gas, and air quality impacts of a new type of boiler briquette coal (BB-coal) in contrast to those of the raw coal from which the BB-coal was formulated (R-coal). The analysis is based on the source emissions data and other relevant data collected in the present study and employs approaches including the construction of carbon, energy, and sulfur balances. The results show that replacing R-coal with BB-coal as the fuel for boilers such as the one tested would have multiple benefits, including a 37% increase in boiler thermal efficiency, a 25% reduction in fuel demand, a 26% reduction in CO2 emission, a 17% reduction in CO emission, a 63% reduction in SO2 emission, a 97% reduction in fly ash and fly ash carbon emission, a 22% reduction in PM2.5 mass emission, and a 30% reduction in total emission of five toxic hazardous air pollutant (HAP) metals contained in PM10. These benefits can be achieved with no changes in boiler hardware and with a relatively small amount of tradeoffs: a 30% increase in PM10 mass emission and a 9-16% increase in fuel cost.

Air Pollution↗
PubMed1992

Patterns of coal workers' pneumoconiosis in Appalachian former coal miners.

To aid in diagnostic chest film interpretation of coal workers' pneumoconiosis, a composite profile of common radiologic patterns was developed in 98 Appalachian former coal miners who were diagnosed as having coal miner's pneumoconiosis and who applied for black lung benefits. The mean age was 61 years, with a lifetime coal mine dust exposure of 18.7 years. Results showed that chest radiographs of coal workers' simple pneumoconiosis contained small irregular linear opacities more frequently (47%) than small rounded opacities. Sparse profusion of all small opacities was the rule. Small opacities involved two out of six lung zones simultaneously 39% of the time while other combinations occurred less frequently. Lower zones were involved more frequently than upper ones. Thickened pleura occurred in 18% of radiographs. Other frequent radiographic abnormalities were parenchymal calcifications (19%), marked emphysema (12%), and inactive tuberculosis (12%). Calcification of the aortic knob, a degenerative process reflecting age, occurred in 9%. Only one instance of complicated coal workers' pneumoconiosis (progressive massive fibrosis) was encountered (0.7%). Many of the descriptive features of coal workers' pneumoconiosis noted in the literature were not observed in this study. Only one instance of complicated pneumoconiosis was encountered.

Appalachian Region↗
PubMed1982

New coal tar extract and coal tar shampoos. Evaluation by epidermal cell DNA synthesis suppression assay.

Coal tar therapy has been used for many years in the treatment of scaling skin diseases, including psoriasis and eczema. Previous studies of the potential effectiveness of tar have utilized phototoxic erythema assays with long-wave ultraviolet light (UV-A). However, in clinical use, coal tar is rarely used with UV-A, particularly for scalp disease. Therefore, we investigated a nonphototoxic approach to evaluate different coal tar products. Coal tar was found to suppress epidermal cell DNA synthesis in the hairless mouse model, and this is the basis for the assay presented. Using the epidermal cell DNA synthesis suppression assay, we observed that crude coal tar and a new extract of crude coal tar were equally effective and that a concentration gradient effect was achieved. In addition, four commercial coal tar shampoos assayed varied greatly in their ability to suppress epidermal cell DNA synthesis. One shampoo was washed after ten minutes and no significant alteration of suppressive effect was seen.

Animals↗
PubMed1997

Respiratory symptoms and spirometry in experienced coal miners: effects of both distant and recent coal mine dust exposures.

The goal of this study was to determine whether respiratory symptoms were associated with the lower concentrations of respirable coal mine dust that were required by the U.S. Coal Mine Health and Safety Act (CMHSA) of 1969. The subjects were 1,866 male miners who had participated in the National Study of Coal Workers' Pneumoconiosis (NSCWP) and been tested at least twice, initially in either Round 1 (R1) (1969-71) or Round 2 (R2) (1972-75) and then finally in Round 4 (R4) (1985-88). Self-reported information elicited with a standardized questionnaire was used to determine the presence at the final round (i.e., R4) of chronic bronchitis, shortness of breath, and wheeze. Cumulative coal mine dust exposure was characterized for both the pre- and post-CMHSA periods. Controlling for age and other potential confounders, increased risks for the symptoms were associated with higher levels of both measurements of exposure. Moreover, the adverse effects of the lower, post-CMHSA exposure were evident for shortness of breath and wheeze especially among subjects who had little pre-CMHSA coal mining experience. These findings provide additional evidence of the limitations of the current 2.0 mg/m3 coal mine dust standard to prevent respiratory disease.

Adult↗
PubMed1983

Role of nitrosation in the mutagenic activity of coal dust: a postulation for gastric carcinogenesis in coal miners.

The mutagenicity of coal dust solvent extracts with and without nitrosation was studied using the Salmonella/microsome assay system. Coal dust solvent extracts were either non-mutagenic or very weakly mutagenic with S9 activation. High mutagenic activities, however, were found when extracts of bituminous, subbituminous, and lignite coal dusts were reacted with nitrite under an acidic condition. Formation of mutagens from coal dust extracts by nitrosation was highest at pH 3.2 and decreased with increasing pH in the reaction mixture. Mutagenic activity appeared to be independent of metabolic activation. The mutagens formed from nitrosation of coal dust extracts induced frameshift mutations. The results reported here may have possible implications for the explanation of an elevated incidence of gastric cancer in coal miners.

Coal↗
PubMed2003

As, Hg, and Se flue gas sampling in a coal-fired power plant and their fate during coal combustion.

As, Hg, and Se are the most volatile elements in the flue gas from a coal-fired power plant. Significant amounts of these elements cause an undesired direct gaseous emission, which leads to a serious environmental health risk. The main focus of this study is to evaluate the possibility of simultaneous sampling of these volatile elements using an accurate official method for Hg (the most volatile element). A study of As, Hg, and Se emissions from a 1400 MW coal-fired power plant equipped with electrostatic precipitators (ESPs) was carried out for the combustion of a mixture of two types of coal. Simultaneous sampling of coal, bottom ash, fly ash, flue gas, and particles associated with the gas phase has been performed. Flue gas has been sampled by the Ontario Hydro Method Sampling Train, an ASTM method for Hg speciation. This sampling method was tested for As and Se sampling. As and Se determinations have been performed by HG-AAS, and Hg has been determined by CV-AAS. The results were used to examine the following: overall mass balances, relative distribution of these elements in the coal-fired power plant; As, Hg, and Se concentrations in coal and combustion residues; and predominant oxidation state for Hg in flue gas. The mass balances obtained for As, Hg, and Se were satisfactory in all cases; nevertheless, relative enrichment values in fly ash for As and Se were low; therefore, we concluded that As sampling in flue gas can be conducted by application of the Ontario Hydro Method; nevertheless Se released in the gas phase is not completely collected by this sampling train. Application of this sampling method allowed for performance of Hg speciation. The results indicated that Hg(II) was the predominant species in flue gas. It has also been proved that 24%, more than 99.8%, and 90% for As, Hg, and Se in the stack emissions, respectively, were in the gaseous phase.

Air Pollutants↗