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Potential health impacts of burning coal beds and waste banks
International Journal of Coal Geology 59 (2004) 19 – 24 www.elsevier.com/locate/ijcoalgeo
Potential health impacts of burning coal beds and waste banks Robert B. Finkelman * U.S. Geological Survey, Mail Stop 956 National Center, 12201 Sunrise Valley Drive, Reston, VA 20192, USA Received 5 August 2003; accepted 4 November 2003 Available online 6 March 2004
Abstract Uncontrolled release of pollutants from burning coal beds and waste banks presents potential environmental and human health hazards. On a global scale, the emissions of large volumes of greenhouse gases from burning coal beds may contribute to climate change that alters ecosystems and patterns of disease occurrence. On regional and local scales, the emissions from burning coal beds and waste banks of acidic gases, particulates, organic compounds, and trace elements can contribute to a range of respiratory and other human health problems. Although there are few published reports of health problems caused by these emissions, the potential for problems can be significant. In India, large numbers of people have been displaced from their homes because of health problems caused by emissions from burning coal beds. Volatile elements such as arsenic, fluorine, mercury, and selenium are commonly enriched in coal deposits. Burning coal beds can volatilize these elements, which then can be inhaled, or adsorbed on crops and foods, taken up by livestock or bioaccumulated in birds and fish. Some of these elements can condense on dust particles that can be inhaled or ingested. In addition, selenium, arsenic, lead, tin, bismuth, fluorine, and other elements condense where the hot gaseous emissions come in contact with ambient air, forming mats of concentrated efflorescent minerals on the surface of the ground. These mats can be leached by rainwater and washed into local water bodies providing other potential routes of exposure. Although there are little data linking burning coal beds and waste banks to known health problems, a possibly analogous situation exists in rural China where mineralized coal burned in a residential environment has caused widespread and severe health problems such as fluorosis and arseniasis. D 2004 Elsevier B.V. All rights reserved. Keywords: Uncontrolled burning; Coal beds; Coal waste banks; Health problems
1. Introduction Coal combustion mobilizes large amounts of pollutants such as sulfur and nitrogen oxides (acidic gases), carbon dioxide, particulate matter, organic compounds, and potentially toxic trace elements such as arsenic, mercury, and selenium. Most modern coalfired power plants in the U.S. and elsewhere try to * Tel.: +1-703-648-6412; fax: +1-703-648-6419. E-mail address: [email protected] (R.B. Finkelman). 0166-5162/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.coal.2003.11.002
minimize the release of these pollutants into the atmosphere by: (1) selecting feed coals with low sulfur and ash contents; (2) controlling the combustion conditions; and (3) employing various post-combustion pollution control systems. Because none of these precautions apply to burning coal beds or to burning coal waste banks, these uncontrolled coal fires introduce large amounts of pollutants into the environment from thousands of sites around the world. It is difficult to think of a natural or anthropogenic process that has absolutely no societal ben-
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efit. Despite the destruction that they cause, volcanoes and forest fires have many beneficial effects. Industrial activity and coal-burning power plants may pollute the environment, but they produce useful products and essential electricity. Coal fires, both surface and in-ground, represent the rare phenomenon that is totally devoid of societal value. Among the problems caused by surface and inground coal fires are:
Visual blight and the loss of potentially valuable acreage; Destruction of the nearby ecosystem; Forest fires; Source of windblown dust and siltation of streams; Deterioration of cultural infrastructure by acid gases; Destruction of personal and public property; Disruption of families and communities; Physical hazards from collapse or explosion; Health hazard due to respiration of dust and aerosols, exposure to acid gases, potentially toxic trace elements, and organic compounds; Pollution of surface and ground water; Loss of valuable energy resources; Significant source of CO2, a major greenhouse gas.
The societal cost of the problems caused by burning surface and in-ground coal runs into the billions of dollars. As an example of only one aspect of the societal costs, Walker (1999) provides an estimate of the costs to extinguish the 150 or so coal fires in the U.S. at nearly US$675,000,000. The benefits of burning surface and in-ground coal are nil. This paper will describe some of the more likely human health problems that may be caused by burning coal beds and waste banks and illustrate some the clinical manifestations of these problems. Such a description will help us better understand the true societal cost of this problem and the benefits of extinguishing the fires. It must be stressed that, to the author’s knowledge, there have been no confirmed reports of these health problems attributed to burning coal beds or burning coal waste banks.
2. History and extent Naturally occurring in-ground coal fires undoubtedly occurred soon after the first coal beds were exposed at the earth’s surface several hundred million years ago. Fission track evidence from the Powder River Basin (Heffern and Coates, 1997) and China (Zhang and Kroonenberg, 1996) indicate that inground coal was burning several million years ago. Natural processes such as lightning strikes started those fires, either directly or indirectly by causing forest and prairie fires that ignited the coal beds exposed at the surface. Moreover, some low-rank coals have a tendency to spontaneously combust when exposed to oxygen. Walker (1999) offers a good discussion of the principal factors involved in selfheating and combustion of coal. The occurrence of uncontrolled coal fires increased following the advent of coal mining because of the increased amount of coal being exposed to oxygen and because of fires associated with the mining activity as well as accidental and intentional fires started on coal waste piles. Many of these fires are ephemeral or intermittent, but some burning coal beds are enormous, consuming many acres and burning for many decades. For example, Heffern and Coates (1997) state that clinker, the baked or melted rock product of burning coal beds, covers about 1600 miles2 of the Powder River Basin. They estimate that this represents about 30 to 40 billion tons of burned coal and that there may have been about 10 times more clinker that has been eroded. The fire in the Jharia coal field in India has been burning since 1916 and the fire that caused the depopulation of Centralia, PA has been burning since 1962. Neither fire shows any signs of abating. Uncontrolled coal fires have been reported from many countries including the U.S., Canada, China, Australia, India, Indonesia, South Africa, England, Germany, Poland, Czech Republic, Russia, Ukraine, Turkey, Thailand, and other countries (Walker, 1999). Unfortunately, few accurate inventories of the coal fires exist. Unofficial estimates from the U.S. Office of Surface Mining indicate that, despite many years of concerted efforts to extinguish these fires, there are still approximately 150 uncontrolled surface and underground coal fires in the U.S. (A.E. Whitehouse, 2003, personal communication).
R.B. Finkelman / International Journal of Coal Geology 59 (2004) 19–24
3. Limited reporting of health effects Despite the abundant literature on the causes of these fires, their environmental impacts, and the efforts to extinguish them, relatively little has been written about the human health impacts of burning coal beds and waste banks. The only report of health problems caused directly by coal bed fires comes from the Jharia Coal Field in India. Stracher (2002), quoting Anupma Prakask, notes that pollution from the burning coal beds are causing people to suffer from asthma, chronic bronchitis, skin disease, and lung disease. The Indian Government has initiated a large-scale relocation plan so that people can escape the high concentration of toxic gases and particulates generated by this and other coal fires. There are several possible explanations for the scarcity of reports on health problems attributed to coal fires. The gross environmental devastation caused by these fires may have deflected attention from the human health problems that they cause. It is possible that the manifestations of the health problems are relatively subtle and have not attracted attention. It is also possible that the health problems caused by these fires are, indeed, very rare. Walker (1999, p.25) addresses this issue by saying: The long-term influence of uncontrolled fires on population health can be difficult to measure, given the masking effect provided by other factors. By their very location, coal mine fires often occur in areas that already have high coal usage, either directly or for power generation, while social practices such as tobacco smoking may also disguise adverse health effects from fire emissions. Thus, for example, the incidence of chronic obstructive pulmonary disease and lung cancer in coal mining areas in China may be related in part to emissions from uncontrolled fires but it is also undoubtedly a result of traditional domestic cooking practices (which use open coal or coke stoves) and cigarette smoking. . . Nevertheless, it would be prudent for researchers studying burning coal beds and waste banks to be aware of the potential health problems that can be
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associated with these phenomena and to be aware of some of the clinical signs that may indicate the existence of these problems.
4. Potential health impacts Virtually all studies characterizing the emissions from coal combustion have focused on the emissions from industrial and commercial coal-fired boilers (EPA, 1996). Few studies have monitored the effluents from residential coal combustion and fewer still have tried to determine the pollutants emitted from burning coal beds and waste piles. In a comprehensive study of minerals forming around vents of surface and in-ground coal fires in the Anthracite Region of Pennsylvania, Lapham et al. (1980) described 33 mineral species, many containing potentially toxic compounds. Among these minerals are: native selenium (Se), galena (PbS), realgar (AsS), orpiment (As2S3), arsenolite (As2O3), downeyite (SeO2), and unnamed As2Se3 (subsequently named laphamite: Dunn et al., 1986), several fluorine bearing minerals such as cryptohalite ((NH4)2SiF6), bararite ((NH4)2SiF6), and an unmanned KAlF4. Some of the minerals were so abundant that they formed a carpet of crystals extending several feet around each vent. Month after month and year after year the gases exiting the vents replenished these minerals. Similar minerals have been found at other burning coal sites in the former Czechoslovakia (Rost, 1937) and Russia (Chesnokov, 1997). Mercury-bearing minerals have not been reported; presumably because it is so volatile that it does not condense near the vents. Lapham et al. (1980) expressed concerns about the possible health impacts of the elements mobilized by the burning coal waste banks. They recommended (p. 77) that there be further study of the trace- and minor-element composition of the air, soil, and water in the vicinity of the burning waste piles. They go on to say that ‘‘Such studies, carried out in conjunction with a compilation of health statistics for the region, would be of use in determining whether. . .’’ there were any harmful effects from the burning coal waste piles. Unfortunately, these studies were never carried out.
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5. Residential coal combustion in China as an analog for burning coal beds and waste banks Lapham et al. (1980) demonstrated that large quantities of potentially toxic trace elements such as arsenic, fluorine, selenium, and lead were mobilized during the life of these burning coal beds and burning coal waste piles. Could the elements emitted from these uncontrolled coal fires cause human heath problems? This question may best be answered by examining a possibly analogous situation that exists in China. In China alone, several hundred million people commonly burn raw coal in unvented stoves, permeating their homes with high levels of potentially toxic organic compounds and metals such as arsenic, fluorine, mercury, and selenium. Some of the health problems caused by this practice are described below. 5.1. Arsenic Chronic arsenic poisoning which affects at least 3000 people in Guizhou Province has been described by Zheng et al. (1996). Those affected exhibit typical symptoms of arsenic poisoning including hyperpigmentation (flushed appearance, freckles), hyperkeratosis (scaly lesions on the skin, generally concentrated on the hands and feet), Bowen’s disease (dark, horny, precancerous lesions of the skin), and squamous cell carcinoma (Fig. 1). Zheng et al. (1996) have shown that ingestion of chili peppers dried over open coal-burning stoves may be a principal route of exposure for the arsenic poisoning. Fresh chili peppers have less than one part-per-million (ppm) arsenic. In contrast, chili peppers dried over high-arsenic coal fires can have more than 500 ppm arsenic. Significant amounts of arsenic may also come from other tainted foods, ingestion of dust (samples of kitchen dust contained as much as 3,000 ppm arsenic), and from inhalation of indoor air polluted by arsenic derived from coal combustion. Belkin et al. (1997a,b, 1998) recently conducted detailed chemical and mineralogical characterization of the arsenic-bearing coal samples from this region. They analyzed about 25 coal samples that they had collected from several locations within Guizhou Province. Instrumental neutron activation analyses of the coal indicate arsenic concentrations as high as 35,000
Fig. 1. Foot displaying hyperkeratosis (scaly lesions) attributable to arsenic poisoning.
ppm! By comparison, the mean concentration for arsenic in nearly 10,000 U.S. coal samples is approximately 22 ppm, with a maximum value of about 2000 ppm (Finkelman, 1993). 5.2. Fluorine The health problems caused by fluorine volatilized during domestic coal use are far more extensive than those caused by arsenic. More than 10 million people in Guizhou Province and surrounding areas suffer from various forms of fluorosis (Zheng and Huang, 1989) and it has also been reported from 13 other Provinces, autonomous regions, and municipalities in China (Ando et al., 1998). Typical signs of fluorosis include mottling of tooth enamel (dental fluorosis) and various forms of skeletal fluorosis including osteosclerosis, limited movement of the joints, and outward manifestations such as knock-knees, bow legs, and spinal curvature. Fluorosis combined with nutritional deficiencies in children can result in severe bone deformation (Fig. 2). The etiology of fluorosis is similar to that of arsenism in that the disease is derived from foods
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sidered to be unique (R. Dart, 1996, personal communication). Mineralogical analysis of the coal being used in the homes of people having visual impairment revealed abundant mercury minerals. Chemical analysis of several coal samples indicated mercury concentrations as high as 55 ppm, about 200 times the average mercury concentration in U.S. coals (note: the average mercury content for coals from other parts of China is similar to the average mercury content of U.S. coals: U.S. Geological Survey unpublished data). 5.4. Selenium
Fig. 2. Deformed feet, a consequence of fluorosis and vitamin D deficiency. Entire families have been affected by this problem.
dried over coal-burning stoves. Zheng and Huang (1989) have demonstrated that adsorption of fluorine by corn dried over unvented ovens burning high (>200 ppm) fluorine coal is the probable cause of the extensive dental and skeletal fluorosis in southwestern China. 5.3. Mercury There is also considerable concern about the health effects of mercury and the proportion of anthropogenic mercury in the environment (EPA, 1998). So far, there is no direct evidence of health problems caused by mercury released from coal but there are circumstances where poisoning from mercury released from coal combustion may be occurring. Zhou and Liu (1985) reported on chronic thallium poisoning in Guizhou Province, China, where the source of the thallium poisoning appears to be from vegetables grown on a mercury –thalliumrich mining slag. Most symptoms, such as hair loss, are typical of thallium poisoning. However, loss of vision in several patients from this region was con-
Zheng et al. (1992) report nearly 500 cases of human selenosis in southwest China that are attributed to the use of selenium-rich carbonaceous shales known locally as ‘‘stone coal.’’ The stone coals have as much as 8390 ppm selenium. This selenosis is attributed to the practice of using combustion ash as a soil amendment. This process introduced large amounts of selenium into the soil and resulted in selenium uptake by crops. Symptoms of selenium poisoning include discoloration of the skin and loss of hair and nails. 5.5. Organic compounds Many studies have been carried out on the high incidence of esophageal and lung cancers in China (Lan et al., 2002), but the dominant causative agents of the cancer remain unclear. Polycyclic aromatic hydrocarbons (PAH) released during unvented coal combustion in homes in China have been cited as the primary cause for the highly elevated incidence of lung cancer (Mumford et al., 1987). Mumford et al. (1995) have linked the high lung cancer mortality rate (five times the national average of China) in Xuan Wei, China to high PAH levels in homes burning ‘‘smokey’’ coal. It has yet to be determined if the PAH are causative factors, contributing factors, or just a coincidental factor.
6. Conclusions Uncontrolled fires in coal beds and coal waste piles around the world are volatilizing large amounts of
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potentially toxic trace elements such as arsenic, selenium, mercury, lead, and fluorine. Studies of the relationship between coal bed and waste bank fires and health problems are rare and inconclusive; however, studies of residential coal use in China have shown that trace elements emitted by these fires have caused widespread and severe health problems. Therefore, by analogy, we might expect that the health of people living near coal bed and waste pile fires may be at risk from the emission of trace elements, gases, and particulates. Scientists studying the phenomenon of these burning coal beds and waste piles can provide a valuable service to the local communities by familiarizing themselves with the clinical signs of exposure to potentially harmful emissions, especially the trace elements. Should there be any indication of possible toxic exposures, the local medical and public health specialists should be notified. Information on the concentrations of the potentially toxic elements in the burning coals would be valuable in helping to anticipate the possible health impacts and establish a more realistic estimate of societal costs of coal bed and waste pile fires. References Ando, M., Tadano, M., Asanuma, S., Matsushima, S., Wanatabe, T., Kondo, T., Sakuai, S., Ji, R., Liang, C., Cao, S., 1998. Health effects of indoor fluoride pollution from coal burning in China. Environmental Health Perspectives 106 (5), 239 – 244. Belkin, H.E., Zheng, B., Finkelman, R.B., 1997a. Geochemistry of coals causing arsenism in southwest China. 4th International Symposium on Environmental Geochemistry. U.S. Geological Survey Open-File Report 97-496, p. 10. Belkin, H.E., Zheng, B., Zhou, D., Finkelman, R.B., 1997bb. Preliminary results on the geochemistry and mineralogy of arsenic in mineralized coals from endemic arsenosis areas in Guizhou Province, People’s Republic of China. Fourteenth Annual International Pittsburgh Coal Conference, CD-ROM. Belkin, H.E., Warwick, P., Zheng, B., Zhou, D., Finkelman, R.B., 1998. High arsenic coals related to sedimentary rock-hosted gold deposition in southwestern Guizhou Province, People’s Republic of China. Fifteenth Annual International Pittsburgh Coal Conference, CD-ROM. Chesnokov, B.V., 1997. Overview of results on mineralogical investigation of burnt dumps of the Chelyabinsk coal basin during 1982 – 1995. 10th report/, Ural’sky mineralogical sbornik N 7. Miass. Institute of Mineralogy, Ural Branch, Russian Academy of Sciences, Ekaterinburg, pp. 5 – 32 (in Russian). Dunn, P.J., Peacor, D.R., Criddle, A.J., Finkelman, R.B., 1986. Laphamite, andarsenic selenide analogue of orpiment from
burning anthracite deposits in Pennsylvania. Mineralogical Magazine 50, 279 – 282. EPA (U.S. Environmental Protection Agency), 1996. Study of hazardous air pollutant emissions from electric utility steam generating units—Interim final report. EPA-453/R-96-013a. EPA (Environmental Protection Agency), 1998. Mercury emissions and electric utilities. http://www.epa.gov/ttn/oarpg/hg17th.html), February 24, 1998. Finkelman, R.B., 1993. Trace and minor elements in coal. In: Engel, M.H., Macko, S.A. (Eds.), Organic Geochemistry. Plenum, New York, pp. 593 – 607. Heffern, E.L., Coates, D.A., 1997. Clinker—Its occurrence, use, and effects on coal mining in the Powder River Basin. Wyoming State Geological Survey Public Information Circular 38, 151 – 166. Lan, Q., Chapman, R.S., Schreinemachers, D.M., Tian, L., He, X., 2002. Household stove improvement and risk of lung cancer in Xuanwei, China. Journal of the National Cancer Institute 94 (11), 826 – 835. Lapham, D.M., Barnes, J.H., Downey Jr., W.F., Finkelman, R.B., 1980. Mineralogy associated with burning anthracite deposits of Eastern Pennsylvania: Pennsylvania Geological Survey. Mineral Resource Report 79 (82 p.). Mumford, J.L., He, X.Z., Chapman, R.S., Cao, S.R., Harris, D.B., Li, X.M., Xian, W.Z., Jiang, C.W., Xu, J.C., Chuang, J.C., Wilson, W.E., Cooke, M., 1987. Lung cancer and indoor air pollution in Xuan Wei, China. Science 235, 217 – 220. Mumford, J.L., Li, X., Hu, F., Lu, X.B., Chaung, J.C., 1995. Human exposure and dosimitry of polycyclic aromatic hydrocarbons in urine from Xuan Wei, China with high lung cancer mortality associated with exposure to unvented coal smoke. Carcinogenesis 16 (12), 3031 – 3036. Rost, R., 1937. The minerals formed on burning heaps in the coal basin of Kladno. Academy of Sciences Bohemia, Bulletin, 47 – 53. Stracher, G.B., 2002. Coal fires—A burning global recipe for catastrophe. Geotimes, vol. 47, no. 10, pp. 36 – 37 and 66. Walker, S., 1999. Uncontrolled fires in coal and coal wastes. International Energy Agency, London. Report CCC/16, 72 p. Zhang, X., Kroonenberg, S.B., 1996. Pleistocene coal fires in Xinjiang, Northwest China. 30th International Geological Congress, vol. 1, pp. 457. Zheng, B., Huang, R., 1989. Human fluorosis and environmental geochemistry in southwest China. Contributions to 28th International Geologic Congress, Washington, DC. Developments in Geoscience Science Press, Beijing, China, pp. 171 – 176. Zheng, B., Hong, Y., Zhao, W., Zhou, H., Xia, W., Su, H., Mao, D., Yan, L., Thornton, I., 1992. The Se-rich carbonaceous siliceous rock and endemic selenosis in southwest Hubei, China. Chinese Science Bulletin 37 (20), 1725 – 1729. Zheng, B., Yu, X., Zhand, J., Zhou, D., 1996. Environmental geochemistry of coal and endemic arsenism in southwest Guizhou, P.R. China. 30th International Geologic Congress, vol. 3, pp. 410. Abstracts. Zhou, D., Liu, D., 1985. Chronic thallium poisoning in a rural area of Guizhou Province, China. Journal of Environmental Health 48 (1), 14 – 18.
Potential health impacts of burning coal beds and waste banks Robert B. Finkelman * U.S. Geological Survey, Mail Stop 956 National Center, 12201 Sunrise Valley Drive, Reston, VA 20192, USA Received 5 August 2003; accepted 4 November 2003 Available online 6 March 2004
Abstract Uncontrolled release of pollutants from burning coal beds and waste banks presents potential environmental and human health hazards. On a global scale, the emissions of large volumes of greenhouse gases from burning coal beds may contribute to climate change that alters ecosystems and patterns of disease occurrence. On regional and local scales, the emissions from burning coal beds and waste banks of acidic gases, particulates, organic compounds, and trace elements can contribute to a range of respiratory and other human health problems. Although there are few published reports of health problems caused by these emissions, the potential for problems can be significant. In India, large numbers of people have been displaced from their homes because of health problems caused by emissions from burning coal beds. Volatile elements such as arsenic, fluorine, mercury, and selenium are commonly enriched in coal deposits. Burning coal beds can volatilize these elements, which then can be inhaled, or adsorbed on crops and foods, taken up by livestock or bioaccumulated in birds and fish. Some of these elements can condense on dust particles that can be inhaled or ingested. In addition, selenium, arsenic, lead, tin, bismuth, fluorine, and other elements condense where the hot gaseous emissions come in contact with ambient air, forming mats of concentrated efflorescent minerals on the surface of the ground. These mats can be leached by rainwater and washed into local water bodies providing other potential routes of exposure. Although there are little data linking burning coal beds and waste banks to known health problems, a possibly analogous situation exists in rural China where mineralized coal burned in a residential environment has caused widespread and severe health problems such as fluorosis and arseniasis. D 2004 Elsevier B.V. All rights reserved. Keywords: Uncontrolled burning; Coal beds; Coal waste banks; Health problems
1. Introduction Coal combustion mobilizes large amounts of pollutants such as sulfur and nitrogen oxides (acidic gases), carbon dioxide, particulate matter, organic compounds, and potentially toxic trace elements such as arsenic, mercury, and selenium. Most modern coalfired power plants in the U.S. and elsewhere try to * Tel.: +1-703-648-6412; fax: +1-703-648-6419. E-mail address: [email protected] (R.B. Finkelman). 0166-5162/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.coal.2003.11.002
minimize the release of these pollutants into the atmosphere by: (1) selecting feed coals with low sulfur and ash contents; (2) controlling the combustion conditions; and (3) employing various post-combustion pollution control systems. Because none of these precautions apply to burning coal beds or to burning coal waste banks, these uncontrolled coal fires introduce large amounts of pollutants into the environment from thousands of sites around the world. It is difficult to think of a natural or anthropogenic process that has absolutely no societal ben-
20
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efit. Despite the destruction that they cause, volcanoes and forest fires have many beneficial effects. Industrial activity and coal-burning power plants may pollute the environment, but they produce useful products and essential electricity. Coal fires, both surface and in-ground, represent the rare phenomenon that is totally devoid of societal value. Among the problems caused by surface and inground coal fires are:
Visual blight and the loss of potentially valuable acreage; Destruction of the nearby ecosystem; Forest fires; Source of windblown dust and siltation of streams; Deterioration of cultural infrastructure by acid gases; Destruction of personal and public property; Disruption of families and communities; Physical hazards from collapse or explosion; Health hazard due to respiration of dust and aerosols, exposure to acid gases, potentially toxic trace elements, and organic compounds; Pollution of surface and ground water; Loss of valuable energy resources; Significant source of CO2, a major greenhouse gas.
The societal cost of the problems caused by burning surface and in-ground coal runs into the billions of dollars. As an example of only one aspect of the societal costs, Walker (1999) provides an estimate of the costs to extinguish the 150 or so coal fires in the U.S. at nearly US$675,000,000. The benefits of burning surface and in-ground coal are nil. This paper will describe some of the more likely human health problems that may be caused by burning coal beds and waste banks and illustrate some the clinical manifestations of these problems. Such a description will help us better understand the true societal cost of this problem and the benefits of extinguishing the fires. It must be stressed that, to the author’s knowledge, there have been no confirmed reports of these health problems attributed to burning coal beds or burning coal waste banks.
2. History and extent Naturally occurring in-ground coal fires undoubtedly occurred soon after the first coal beds were exposed at the earth’s surface several hundred million years ago. Fission track evidence from the Powder River Basin (Heffern and Coates, 1997) and China (Zhang and Kroonenberg, 1996) indicate that inground coal was burning several million years ago. Natural processes such as lightning strikes started those fires, either directly or indirectly by causing forest and prairie fires that ignited the coal beds exposed at the surface. Moreover, some low-rank coals have a tendency to spontaneously combust when exposed to oxygen. Walker (1999) offers a good discussion of the principal factors involved in selfheating and combustion of coal. The occurrence of uncontrolled coal fires increased following the advent of coal mining because of the increased amount of coal being exposed to oxygen and because of fires associated with the mining activity as well as accidental and intentional fires started on coal waste piles. Many of these fires are ephemeral or intermittent, but some burning coal beds are enormous, consuming many acres and burning for many decades. For example, Heffern and Coates (1997) state that clinker, the baked or melted rock product of burning coal beds, covers about 1600 miles2 of the Powder River Basin. They estimate that this represents about 30 to 40 billion tons of burned coal and that there may have been about 10 times more clinker that has been eroded. The fire in the Jharia coal field in India has been burning since 1916 and the fire that caused the depopulation of Centralia, PA has been burning since 1962. Neither fire shows any signs of abating. Uncontrolled coal fires have been reported from many countries including the U.S., Canada, China, Australia, India, Indonesia, South Africa, England, Germany, Poland, Czech Republic, Russia, Ukraine, Turkey, Thailand, and other countries (Walker, 1999). Unfortunately, few accurate inventories of the coal fires exist. Unofficial estimates from the U.S. Office of Surface Mining indicate that, despite many years of concerted efforts to extinguish these fires, there are still approximately 150 uncontrolled surface and underground coal fires in the U.S. (A.E. Whitehouse, 2003, personal communication).
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3. Limited reporting of health effects Despite the abundant literature on the causes of these fires, their environmental impacts, and the efforts to extinguish them, relatively little has been written about the human health impacts of burning coal beds and waste banks. The only report of health problems caused directly by coal bed fires comes from the Jharia Coal Field in India. Stracher (2002), quoting Anupma Prakask, notes that pollution from the burning coal beds are causing people to suffer from asthma, chronic bronchitis, skin disease, and lung disease. The Indian Government has initiated a large-scale relocation plan so that people can escape the high concentration of toxic gases and particulates generated by this and other coal fires. There are several possible explanations for the scarcity of reports on health problems attributed to coal fires. The gross environmental devastation caused by these fires may have deflected attention from the human health problems that they cause. It is possible that the manifestations of the health problems are relatively subtle and have not attracted attention. It is also possible that the health problems caused by these fires are, indeed, very rare. Walker (1999, p.25) addresses this issue by saying: The long-term influence of uncontrolled fires on population health can be difficult to measure, given the masking effect provided by other factors. By their very location, coal mine fires often occur in areas that already have high coal usage, either directly or for power generation, while social practices such as tobacco smoking may also disguise adverse health effects from fire emissions. Thus, for example, the incidence of chronic obstructive pulmonary disease and lung cancer in coal mining areas in China may be related in part to emissions from uncontrolled fires but it is also undoubtedly a result of traditional domestic cooking practices (which use open coal or coke stoves) and cigarette smoking. . . Nevertheless, it would be prudent for researchers studying burning coal beds and waste banks to be aware of the potential health problems that can be
21
associated with these phenomena and to be aware of some of the clinical signs that may indicate the existence of these problems.
4. Potential health impacts Virtually all studies characterizing the emissions from coal combustion have focused on the emissions from industrial and commercial coal-fired boilers (EPA, 1996). Few studies have monitored the effluents from residential coal combustion and fewer still have tried to determine the pollutants emitted from burning coal beds and waste piles. In a comprehensive study of minerals forming around vents of surface and in-ground coal fires in the Anthracite Region of Pennsylvania, Lapham et al. (1980) described 33 mineral species, many containing potentially toxic compounds. Among these minerals are: native selenium (Se), galena (PbS), realgar (AsS), orpiment (As2S3), arsenolite (As2O3), downeyite (SeO2), and unnamed As2Se3 (subsequently named laphamite: Dunn et al., 1986), several fluorine bearing minerals such as cryptohalite ((NH4)2SiF6), bararite ((NH4)2SiF6), and an unmanned KAlF4. Some of the minerals were so abundant that they formed a carpet of crystals extending several feet around each vent. Month after month and year after year the gases exiting the vents replenished these minerals. Similar minerals have been found at other burning coal sites in the former Czechoslovakia (Rost, 1937) and Russia (Chesnokov, 1997). Mercury-bearing minerals have not been reported; presumably because it is so volatile that it does not condense near the vents. Lapham et al. (1980) expressed concerns about the possible health impacts of the elements mobilized by the burning coal waste banks. They recommended (p. 77) that there be further study of the trace- and minor-element composition of the air, soil, and water in the vicinity of the burning waste piles. They go on to say that ‘‘Such studies, carried out in conjunction with a compilation of health statistics for the region, would be of use in determining whether. . .’’ there were any harmful effects from the burning coal waste piles. Unfortunately, these studies were never carried out.
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5. Residential coal combustion in China as an analog for burning coal beds and waste banks Lapham et al. (1980) demonstrated that large quantities of potentially toxic trace elements such as arsenic, fluorine, selenium, and lead were mobilized during the life of these burning coal beds and burning coal waste piles. Could the elements emitted from these uncontrolled coal fires cause human heath problems? This question may best be answered by examining a possibly analogous situation that exists in China. In China alone, several hundred million people commonly burn raw coal in unvented stoves, permeating their homes with high levels of potentially toxic organic compounds and metals such as arsenic, fluorine, mercury, and selenium. Some of the health problems caused by this practice are described below. 5.1. Arsenic Chronic arsenic poisoning which affects at least 3000 people in Guizhou Province has been described by Zheng et al. (1996). Those affected exhibit typical symptoms of arsenic poisoning including hyperpigmentation (flushed appearance, freckles), hyperkeratosis (scaly lesions on the skin, generally concentrated on the hands and feet), Bowen’s disease (dark, horny, precancerous lesions of the skin), and squamous cell carcinoma (Fig. 1). Zheng et al. (1996) have shown that ingestion of chili peppers dried over open coal-burning stoves may be a principal route of exposure for the arsenic poisoning. Fresh chili peppers have less than one part-per-million (ppm) arsenic. In contrast, chili peppers dried over high-arsenic coal fires can have more than 500 ppm arsenic. Significant amounts of arsenic may also come from other tainted foods, ingestion of dust (samples of kitchen dust contained as much as 3,000 ppm arsenic), and from inhalation of indoor air polluted by arsenic derived from coal combustion. Belkin et al. (1997a,b, 1998) recently conducted detailed chemical and mineralogical characterization of the arsenic-bearing coal samples from this region. They analyzed about 25 coal samples that they had collected from several locations within Guizhou Province. Instrumental neutron activation analyses of the coal indicate arsenic concentrations as high as 35,000
Fig. 1. Foot displaying hyperkeratosis (scaly lesions) attributable to arsenic poisoning.
ppm! By comparison, the mean concentration for arsenic in nearly 10,000 U.S. coal samples is approximately 22 ppm, with a maximum value of about 2000 ppm (Finkelman, 1993). 5.2. Fluorine The health problems caused by fluorine volatilized during domestic coal use are far more extensive than those caused by arsenic. More than 10 million people in Guizhou Province and surrounding areas suffer from various forms of fluorosis (Zheng and Huang, 1989) and it has also been reported from 13 other Provinces, autonomous regions, and municipalities in China (Ando et al., 1998). Typical signs of fluorosis include mottling of tooth enamel (dental fluorosis) and various forms of skeletal fluorosis including osteosclerosis, limited movement of the joints, and outward manifestations such as knock-knees, bow legs, and spinal curvature. Fluorosis combined with nutritional deficiencies in children can result in severe bone deformation (Fig. 2). The etiology of fluorosis is similar to that of arsenism in that the disease is derived from foods
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sidered to be unique (R. Dart, 1996, personal communication). Mineralogical analysis of the coal being used in the homes of people having visual impairment revealed abundant mercury minerals. Chemical analysis of several coal samples indicated mercury concentrations as high as 55 ppm, about 200 times the average mercury concentration in U.S. coals (note: the average mercury content for coals from other parts of China is similar to the average mercury content of U.S. coals: U.S. Geological Survey unpublished data). 5.4. Selenium
Fig. 2. Deformed feet, a consequence of fluorosis and vitamin D deficiency. Entire families have been affected by this problem.
dried over coal-burning stoves. Zheng and Huang (1989) have demonstrated that adsorption of fluorine by corn dried over unvented ovens burning high (>200 ppm) fluorine coal is the probable cause of the extensive dental and skeletal fluorosis in southwestern China. 5.3. Mercury There is also considerable concern about the health effects of mercury and the proportion of anthropogenic mercury in the environment (EPA, 1998). So far, there is no direct evidence of health problems caused by mercury released from coal but there are circumstances where poisoning from mercury released from coal combustion may be occurring. Zhou and Liu (1985) reported on chronic thallium poisoning in Guizhou Province, China, where the source of the thallium poisoning appears to be from vegetables grown on a mercury –thalliumrich mining slag. Most symptoms, such as hair loss, are typical of thallium poisoning. However, loss of vision in several patients from this region was con-
Zheng et al. (1992) report nearly 500 cases of human selenosis in southwest China that are attributed to the use of selenium-rich carbonaceous shales known locally as ‘‘stone coal.’’ The stone coals have as much as 8390 ppm selenium. This selenosis is attributed to the practice of using combustion ash as a soil amendment. This process introduced large amounts of selenium into the soil and resulted in selenium uptake by crops. Symptoms of selenium poisoning include discoloration of the skin and loss of hair and nails. 5.5. Organic compounds Many studies have been carried out on the high incidence of esophageal and lung cancers in China (Lan et al., 2002), but the dominant causative agents of the cancer remain unclear. Polycyclic aromatic hydrocarbons (PAH) released during unvented coal combustion in homes in China have been cited as the primary cause for the highly elevated incidence of lung cancer (Mumford et al., 1987). Mumford et al. (1995) have linked the high lung cancer mortality rate (five times the national average of China) in Xuan Wei, China to high PAH levels in homes burning ‘‘smokey’’ coal. It has yet to be determined if the PAH are causative factors, contributing factors, or just a coincidental factor.
6. Conclusions Uncontrolled fires in coal beds and coal waste piles around the world are volatilizing large amounts of
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potentially toxic trace elements such as arsenic, selenium, mercury, lead, and fluorine. Studies of the relationship between coal bed and waste bank fires and health problems are rare and inconclusive; however, studies of residential coal use in China have shown that trace elements emitted by these fires have caused widespread and severe health problems. Therefore, by analogy, we might expect that the health of people living near coal bed and waste pile fires may be at risk from the emission of trace elements, gases, and particulates. Scientists studying the phenomenon of these burning coal beds and waste piles can provide a valuable service to the local communities by familiarizing themselves with the clinical signs of exposure to potentially harmful emissions, especially the trace elements. Should there be any indication of possible toxic exposures, the local medical and public health specialists should be notified. Information on the concentrations of the potentially toxic elements in the burning coals would be valuable in helping to anticipate the possible health impacts and establish a more realistic estimate of societal costs of coal bed and waste pile fires. References Ando, M., Tadano, M., Asanuma, S., Matsushima, S., Wanatabe, T., Kondo, T., Sakuai, S., Ji, R., Liang, C., Cao, S., 1998. Health effects of indoor fluoride pollution from coal burning in China. Environmental Health Perspectives 106 (5), 239 – 244. Belkin, H.E., Zheng, B., Finkelman, R.B., 1997a. Geochemistry of coals causing arsenism in southwest China. 4th International Symposium on Environmental Geochemistry. U.S. Geological Survey Open-File Report 97-496, p. 10. Belkin, H.E., Zheng, B., Zhou, D., Finkelman, R.B., 1997bb. Preliminary results on the geochemistry and mineralogy of arsenic in mineralized coals from endemic arsenosis areas in Guizhou Province, People’s Republic of China. Fourteenth Annual International Pittsburgh Coal Conference, CD-ROM. Belkin, H.E., Warwick, P., Zheng, B., Zhou, D., Finkelman, R.B., 1998. High arsenic coals related to sedimentary rock-hosted gold deposition in southwestern Guizhou Province, People’s Republic of China. Fifteenth Annual International Pittsburgh Coal Conference, CD-ROM. Chesnokov, B.V., 1997. Overview of results on mineralogical investigation of burnt dumps of the Chelyabinsk coal basin during 1982 – 1995. 10th report/, Ural’sky mineralogical sbornik N 7. Miass. Institute of Mineralogy, Ural Branch, Russian Academy of Sciences, Ekaterinburg, pp. 5 – 32 (in Russian). Dunn, P.J., Peacor, D.R., Criddle, A.J., Finkelman, R.B., 1986. Laphamite, andarsenic selenide analogue of orpiment from
burning anthracite deposits in Pennsylvania. Mineralogical Magazine 50, 279 – 282. EPA (U.S. Environmental Protection Agency), 1996. Study of hazardous air pollutant emissions from electric utility steam generating units—Interim final report. EPA-453/R-96-013a. EPA (Environmental Protection Agency), 1998. Mercury emissions and electric utilities. http://www.epa.gov/ttn/oarpg/hg17th.html), February 24, 1998. Finkelman, R.B., 1993. Trace and minor elements in coal. In: Engel, M.H., Macko, S.A. (Eds.), Organic Geochemistry. Plenum, New York, pp. 593 – 607. Heffern, E.L., Coates, D.A., 1997. Clinker—Its occurrence, use, and effects on coal mining in the Powder River Basin. Wyoming State Geological Survey Public Information Circular 38, 151 – 166. Lan, Q., Chapman, R.S., Schreinemachers, D.M., Tian, L., He, X., 2002. Household stove improvement and risk of lung cancer in Xuanwei, China. Journal of the National Cancer Institute 94 (11), 826 – 835. Lapham, D.M., Barnes, J.H., Downey Jr., W.F., Finkelman, R.B., 1980. Mineralogy associated with burning anthracite deposits of Eastern Pennsylvania: Pennsylvania Geological Survey. Mineral Resource Report 79 (82 p.). Mumford, J.L., He, X.Z., Chapman, R.S., Cao, S.R., Harris, D.B., Li, X.M., Xian, W.Z., Jiang, C.W., Xu, J.C., Chuang, J.C., Wilson, W.E., Cooke, M., 1987. Lung cancer and indoor air pollution in Xuan Wei, China. Science 235, 217 – 220. Mumford, J.L., Li, X., Hu, F., Lu, X.B., Chaung, J.C., 1995. Human exposure and dosimitry of polycyclic aromatic hydrocarbons in urine from Xuan Wei, China with high lung cancer mortality associated with exposure to unvented coal smoke. Carcinogenesis 16 (12), 3031 – 3036. Rost, R., 1937. The minerals formed on burning heaps in the coal basin of Kladno. Academy of Sciences Bohemia, Bulletin, 47 – 53. Stracher, G.B., 2002. Coal fires—A burning global recipe for catastrophe. Geotimes, vol. 47, no. 10, pp. 36 – 37 and 66. Walker, S., 1999. Uncontrolled fires in coal and coal wastes. International Energy Agency, London. Report CCC/16, 72 p. Zhang, X., Kroonenberg, S.B., 1996. Pleistocene coal fires in Xinjiang, Northwest China. 30th International Geological Congress, vol. 1, pp. 457. Zheng, B., Huang, R., 1989. Human fluorosis and environmental geochemistry in southwest China. Contributions to 28th International Geologic Congress, Washington, DC. Developments in Geoscience Science Press, Beijing, China, pp. 171 – 176. Zheng, B., Hong, Y., Zhao, W., Zhou, H., Xia, W., Su, H., Mao, D., Yan, L., Thornton, I., 1992. The Se-rich carbonaceous siliceous rock and endemic selenosis in southwest Hubei, China. Chinese Science Bulletin 37 (20), 1725 – 1729. Zheng, B., Yu, X., Zhand, J., Zhou, D., 1996. Environmental geochemistry of coal and endemic arsenism in southwest Guizhou, P.R. China. 30th International Geologic Congress, vol. 3, pp. 410. Abstracts. Zhou, D., Liu, D., 1985. Chronic thallium poisoning in a rural area of Guizhou Province, China. Journal of Environmental Health 48 (1), 14 – 18.