Coal Combustion Waste

By Dr. Michael J. Lynch, University of South Florida, FL

Coal combustion waste (CCW) is the waste that remains following the production and/or burning of coal. CCW are serious pollutants, and contain a number of toxins and hazardous pollutants. Coal is a widely used form of fossil fuel in the US, and makes a significant contribution to America’s production and pollution waste streams. For example, research indicates that CCW is the second largest waste stream in the US, ranking only behind municipal waste (Sturgis, 2009).

CCW causes extensive public and environment harm. Both the production and storage of CCW causes environmental contamination to above and below ground water resources. Moreover, CCW contributes to land pollution those wastes leach from CCW sites, and to air pollution in the production of those wastes and when stored coal wastes enter the atmosphere. Many of these problems occur because once produced, CCW is largely unregulated in the US.

Cherry et at (1979) were among the first to recognize the public and environmental health problems associated with CCW. Coal is widely used in the US because of its abundance, and is estimated to account for 90% of all fossil fuel wastes in the US (Carlson and Adriano, 1993). Studies indicate that CCW has significant impacts on the food chain (Carlson and Adriano, 1993) and water resources, causing a number of deleterious health and behavioral effects for vertebrate and invertebrate aquatic species (Rowe, Hopkins and Congdon, 2002). CCW contains a number of harmful trace elements and other pollutants that pose health risks (Xu et al., 2004; Karuppiah and Gupta, 1997) including polychlorinated dioxins (Gullett and Raghunathan, 1997), one of the most dangerous carcinogens known to science.

The potential harms caused by CCW can be intensified due to the co-occurrence of other conditions at CCW sites, such as the presence of acids. These acids can accelerate chemical leaching of metal and toxins into the environment (Karuppiah and Gupta, 1997). Research has examined whether these kinds of problems can be remedied by the “switch” to “clean coal technology.” As Dellantonio et al., (2010) note, however, clean coal technologies tend to concentrate toxins in “clean coal,” increasing exposure to certain toxins when coal is combusted.

In the US, CCW sites are unregulated and there is no requirement that they be tracked or reported, so public knowledge concerning these sites is limited. In response to those conditions, the US EPA recently released (June 2012) released an estimate of the total number of coal ash dump sites in the US that identified 1,161 known surface and lagoon impoundments. An important finding of that study was that nearly one half of those waste sites are unlined. This is a serious concern since unlined waste sites allow wastes to leach into the environment more easily.

In the US< CCW sites tend to be quite large. It is estimated that all sites combined hold 129 million tons of solid and liquid waste (Sturgis, 2009). Based on that estimate we can calculate that the average site holds about 111,000 tons of CCW.

How much public health damage is caused by CCW sites? That is a question has not yet been fully addressed. In a 2006, however, Abt Associates (2010) examined the public health consequences associated with small particle matter emission (PM < 2.5 microns) for the 100 largest (about 10%) of CCW sites in the US. From those data, Abt estimated the number of deaths, illnesses and costs associated with public exposure to the particle waste generated by coal fired power plants impoundments. PM < 2.5 pollution causes serious health problems because they are readily inhaled and promote lung and heart diseases as well as cancer. The Abt data indicate that PM , 2.5 emissions from CCW sites cause up to twice as many deaths as homicides in the US.

In 2010, the US EPA published a study on the human health and ecological impacts of groundwater contamination from “high volume” CCW sites. The study took several exposure pathways into account. The assessment measures included: (1) lifetime cancer risk scores (ranging from 1 per 10,000 to 1 per 100,000 individuals); (2) no cancer health quotient (HQ) risk; and (3) HQ for ecological risk effects for 41 chemicals found in 140 CCW sites (about 12% of all known CCW sites in the US) . Significant health risks were discovered for several chemicals. Those risks vary depending on the construction of the CCW waste sites (unlined sites produce the most serious outcomes followed by clay-lined and composite line waste sites). Cancer risks were discovered for arsenic and noncancer risks were found for antimony, cadmium, cobalt, lead, molybdenum, nitrates/nitrites, selenium, and thallium.

Further Reading
Abt Associates. (2010). Technical Support Document for Powerplant Impact Estimator Software Tool.

Carlson, Claire L., and Domy C. Adriano. 1993. Environmental Impacts of Coal Combustion Waste. Journal of Environmental Quality 22,2: 227-247.

Cherry, Donald S., Stephan R. Larrick, Rufus K. Guthrie, Ernst M. Davis, Fred F. Sherberger. 1979. Recovery of Vertebrate and Invertebrate Populations in a Coal Ash Stressed Drainage System. Journal of the Fisheries Research Board of Canada. 36, 9: 1089-1096.

Gullett, Brian K., and K. Raghunathan. 1997. Observations of the effect of process parameters on dioxin/furan Yield in Municipal Waste and Coal Systems. Chemosphere 34, 5-7: 1027-1032.

Karuppiah, Makesh, and Gian Gupta. 1997. Toxicity of Metals in Coal Combustion Ash Leachate. Journal of Hazardous Materials 56, 1-2: 53-58.

Rowe, Christoper L., William A. Hopkins and Justin D. Congdon. 2002. Exo- toxicological Implications of Aquatic Disposal of Coal Combustion Residues in the United States: A Review. Environmental Monitoring and Assessment 80, 3: 207-276.

Sturgis, Sue. (2009). “Coal’s Ticking Timebomb: Could disaster strike a coal ash dump near you?” Facing South: A New Voice for the Changing South. The Institute for Southern Studies.

US EPA. (2010). Human and Ecological Risk Assessment of Coal Combustion Wastes. Washington, DC: US EPA.

Xu, Minghou, Rong Yan, Chuguang Zheng, Yu Qiao and Changdong Sheng. 2004. Status of Trace Element Emissions in a Coal Combustion Process: A Review. Fuel Processing Technology 85, 2-3: 215-237.

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