Heavy metals and coal

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This article is part of the Coal Issues portal on SourceWatch, a project of Global Energy Monitor and the Center for Media and Democracy. See here for help on adding material to CoalSwarm.

Heavy metal refers to any metallic chemical element that has a high density and is toxic or poisonous at low concentrations. Coal contains many heavy metals, as it is created through compressed organic matter containing virtually every element in the periodic table - mainly carbon, but also heavy metals. The heavy metal content of coal varies by coal seam and geographic region. A variety of chemicals (mostly metals) are associated with coal that are either found in the coal directly or in the layers of rock that lie above and between the seams of coal.[1][2]

Small amounts of heavy metals can be necessary for health, but too much may cause acute or chronic toxicity (poisoning). Many of the heavy metals released in the mining and burning of coal are environmentally and biologically toxic elements, such as lead, mercury, nickel, tin, cadmium, antimony, and arsenic, as well as radio isotopes of thorium and strontium.[3]

The electric power sector is the largest source of toxic pollutants in the United States, due to coal ash and coal waste, which contain toxins such as heavy metals.[4] Each year, the waste left over from burning coal generates 125 to 130 million tons of coal ash and coal sludge -- 40% of that waste finds it way into new products and 60% is stored in ponds or pits, which can present health and environmental risks if released into ground water.[5] Despite this, as of March 2010 coal ash is categorized as nonhazardous and is not regulated by the EPA.[6]

Coal Ash

Burning coal produces airborne compounds, known as fly ash and bottom ash (collectively referred to as coal ash), which can contain large quantities of heavy metals that settle or wash out of the atmosphere into oceans, streams, and land.[3][7] The amount of fly ash is going up: in 2006, coal plants in the United States produced almost 72 million tons, up 50 percent since 1993.[8]

The 1.05 billion tons of coal burned each year in the United States contain 109 tons of mercury, 7884 tons of arsenic, 1167 tons of beryllium, 750 tons of cadmium, 8810 tons of chromium, 9339 tons of nickel, and 2587 tons of selenium. On top of emitting 1.9 billion tons of carbon dioxide each year, coal-fired power plants in the United States also create 120 million tons of toxic waste. That means each of the nation's 500 coal-fired power plants produces an average 240,000 tons of toxic waste each year. A power plant that operates for 40 years will leave behind 9.6 million tons of toxic waste.[7] This coal combustion waste (CCW) constitutes the nation's second largest waste stream after municipal solid waste.[9]

When coal is burned, toxins in the coal are released into the smokestack. With modern air pollution controls, airborne toxins are captured through filtration systems before they can become airborne, and contained in a fine ash called coal ash, fly ash, or coal combustion waste. As a result, heavy metals such as mercury are concentrated in what the EPA considers "recycled air pollution control residue."[8]

Rain falling on coal storage piles and ash piles can leach out these heavy metal compounds into ground water or lakes and streams, contaminating drinking water sources.[3]

Coal Sludge

Coal sludge, the liquid coal waste produced by mining activities (also known as slurry), contains heavy metals. The sludge is often kept in impoundments that can leach into the environment, or break open and contaminate an area, such as the TVA Kingston Fossil Plant coal ash spill and the TVA Widows Creek coal waste spill.[4]

List of Heavy Metals in Coal

Some of the most commonly found chemicals in coal and coal waste include:[2]

Toxic Effects of Heavy Metals

Small amounts of heavy metals can be necessary for health, but too much may cause acute or chronic toxicity (poisoning). The constant leaching of heavy metals from coal mining and coal plants leads to bioaccumulation in plants and animals, creating the danger of toxicity.[3] Heavy metal toxicity can result in damaged or reduced mental and central nervous function, lower energy levels, and damage to blood composition, lungs, kidneys, liver, and other vital organs. Long-term exposure can result in slowly progressing physical, muscular, and neurological degenerative processes that mimic Alzheimer's disease, Parkinson's disease, muscular dystrophy, and multiple sclerosis. Allergies are not uncommon and repeated long-term contact with some metals may even cause cancer.[10]


Electrical utilities emit lead in flue gas from the burning of fuels, such as coal, in which lead is a contaminant. For example, a boiler burning a million pounds of lignite coal will release 420 pounds of lead into the atmosphere.[11]

The American Academy of Pediatrics has stated that there is no “safe level” of lead for children. In fact, acceptable lead exposure limits for all people have been repeatedly lowered over the years and current scientific understanding suggests that neurological damage can occur at blood lead levels much lower than previously believed. Exposure to small amounts of lead can be harmful. The body stores lead in bones, and small amounts of lead can build up in the body and cause lifelong learning and behavior problems. In particular, small amounts of lead in the body can make it difficult for children to learn, pay attention and succeed in school. Lead is released from a mother’s bones during pregnancy, enters the bloodstream, and crosses the placenta, resulting in harmful effects on the fetus.[11] Lead accounts for most of the cases of pediatric heavy metal poisoning.[10]

Because lead does not degrade, the burning of coal and former uses of lead leave their legacy as higher concentrations of lead in the environment. Levels of lead in the environment have increased more than 1,000-fold over the past three centuries as a result of human activity. The greatest increase occurred between the years 1950 and 2000, and reflects increasing worldwide use of leaded gasoline. In 1979, cars released 94.6 million kilograms (208.1 million pounds) of lead into the air in the United States. In 1989, when the use of lead was limited but not banned, cars still released 2.2 million kg (4.8 million pounds) to the air. The EPA did not ban the use of leaded gasoline for highway transportation until 1996. Leaded gasoline continues to be used throughout the globe, including countries from which the United States increasingly imports its food supply. Lead has also been introduced to our environment through coal burning by utilities, as well as mining activity, the use of lead-based paint, and the application of pesticides that contained metals, such as lead arsenate used in fruit orchards.[11]

Whatever its source, lead that falls onto soil sticks strongly to soil particles and remains in the upper layer of soil. Since it does not degrade over time, this contamination problem continues. It can be taken up by plants, and food processing can often introduce lead contamination through bronze plumbing parts, lead in water, or other sources. In 2010, the Environmental Law Foundation enlisted a U.S. Environmental Protection Agency lab to screen 400 samples from 150 branded food products marketed to children, including apple juice, grape juice, packaged pears and peaches (including baby food), and fruit cocktail mixes. The results: 125 out of 146 products tested, or 85 percent, contained alarming amounts of lead.[11]


Most Power Plants Still Spewing Toxic Mercury

Coal-fired power plants are the largest source of mercury in the United States, accounting for about 41 percent (48 tons in 1999) of industrial releases (see Mercury and coal). Tuna and other fish absorb this mercury run-off. According to the Centers for Disease Control and Prevention, eight percent of American women of childbearing age had unsafe levels of mercury in their blood, putting approximately 322,000 newborns at risk of neurological deficits. Mercury exposure also can lead to increase cardiovascular risk in adults.[12] When mercury is deposited on land or in water, microorganisms convert part of it to a highly toxic form called methylmercury. When fish and animals eat these microorganisms, the toxins accumulate and can interfere with reproduction, growth, and behavior, and can even cause death.[13]

In August 2009, the U.S. Geological Survey released a study of mercury contamination in fish in 291 streams around the country. The study, which is the most comprehensive to date, was conducted from 1998 to 2005 and tested over 1,000 fish. Every single fish tested, including those from isolated rural waterways, had at least trace amounts of toxic mercury.[14]

In March 2010 the Environmental Integrity Project (EIP) released a report using available EPA data that indicated half of the country's 50 largest mercury-emitting power plants have increased their emissions in recent years, as can be seen in this video.[15]


Arsenic is the most common cause of acute heavy metal poisoning in adults, and does not leave the body once it enters.[10]


Coal Waste

Despite the negative health and environmental effects of heavy metals, as of March 2010 coal ash is categorized as nonhazardous and is therefore not regulated by the EPA. In May 2009, the Environmental Integrity Project and Earthjustice released a report finding that the Bush Administration failed to release information suggesting an alarmingly high cancer threat for people who live near coal ash waste dumps. According to the study, the Bush Administration only made a portion of the data available, hiding the true extent of the health risks associated with coal ash disposal sites.[6]

October 2009: Proposed Regulation of Coal Waste

Arsenic on your cereal?

In October of 2009 the EPA sent the White House a Notice of Proposed Rulemaking for toxic coal ash. President Obama's choice as the head of the White House Office of Management and Budget, Cass Sunstein, oversees such policies, but as of March 2010 has refused to act on the EPA's plea. Sunstein has come under scrutiny for allowing his office to meet with coal industry representatives more than 20 times since October 2010. All such meetings took place behind closed doors and were not open to the public. An anti-Sunstein website was launched in response in an attempt to force Sunstein and the White House to act on the EPA's proposed rule.[16]

In December 2009, there was a Congressional hearing in the House Energy and Commerce Subcommittee on "Drinking Water and Public Health Impacts of Coal Combustion Waste Disposal," largely in response to the 2008 TVA Kingston Fossil Plant coal ash spill and EPA reports on the health and environmental risks of coal ash and coal waste. Dr. Donald McGraw, the GOP's expert witness at the hearing, testified that arsenic is natural and coal waste benign, as seen in this video.

May 2010: EPA Proposes Competing Approaches To Regulate Coal-Ash Waste

On May 4, 2010 the U.S. EPA announced two competing proposals to regulate coal-ash waste produced by coal-fired power plants. Both options fall under the Resource Conservation and Recovery Act (RCRA). Under the first proposal, EPA would list coal ash and coal waste residuals as "special wastes," or hazardous wastes, subject to regulation under subtitle C of RCRA, when destined for disposal in landfills or surface impoundments. Treatment, storage, and disposal facilities (TSDFs) manage hazardous wastes under RCRA Subtitle C, and generally must have a permit in order to operate, with land disposal restrictions. Under the second proposal, EPA would regulate coal ash under subtitle D of RCRA, the section for non-hazardous wastes. Under section D, no permit is required, monitoring is done by citizens, not the federal government, and there are no restrictions on land disposal of the waste.[17] Click here for more on the key differences between the proposed rules.

The proposal means the EPA will not necessarily declare coal ash a hazardous waste as desired by environmental groups, and the waste material could continue to be reused in various ways, EPA officials said. The final decision on which proposal the EPA will choose was to happen in July 2010,[18] but has been delayed.

The EPA decided not to choose a single option amid pressure from industry and environmental groups. The federal agency said both proposals for the first time would place "national rules on the disposal and management of the waste material from coal-fired power plants." Yet the EPA's plan leaves open the question of whether to phase out wet storage impoundments in favor of landfills, with the dueling proposals differing on the issue, according to an EPA press briefing.[19]

On May 10, 2010 the Illinois-based Prairie Rivers Network released a press memo criticizing the EPA's decision, stating:

The agency presented two options with vastly differing approaches to handling the 4.4 million tons of coal ash that is generated each year in Illinois. Recent USEPA reports indicate that coal waste leaches hazardous pollution in much greater quantities than had been recognized previously, contributing to over 100 documented contamination sites nationwide, several of which are in Illinois.
But another big concern for Illinois is the giant loophole left in the rules that will allow the coal industry to dump toxic coal ash in under-regulated and unprotected mines.[20]

Coal Emissions

March 2011: New EPA Standards for Mercury and Air Toxics Proposed

On March 16, 2011, the U.S. Environmental Protection Agency (EPA) announced its proposed emissions standards to limit mercury, acid gases and other toxic pollution from power plants, to prevent an estimated 91 percent of the mercury in coal from being released to the air. The EPA estimates that there are approximately 1,350 units affected by the action, including 1,200 existing coal-fired units.[21]

There are currently no existing national limits on the amount of mercury and other toxic air pollution released from power plant smokestacks. The 1990 Clean Air Act Amendments mandated EPA control toxic air pollutants, and the EPA took action to reduce mercury emissions from the highest-emitting sources, except power plants, as the Clean Air Mercury Rule passed under President George W. Bush was vacated by a court.[21]

The proposed toxics rule would reduce emissions of heavy metals, including mercury (Hg), arsenic, chromium, and nickel, and acid gases, including hydrogen chloride (HCl) and hydrogen fluoride (HF). EPA is also proposing to revise the New Source Review performance standards (NSPS) for fossil-fuel-fired plants. This NSPS would revise the standards new coal- and oil-fired power plants must meet for particulate matter (PM), sulfur dioxide (SO2), and nitrogen oxides (NOx). The proposed standards should reduce mercury emissions from power plants burning coal and oil by 91 percent, acid gas pollution by 91 percent, direct particulate matter emissions by 30 percent, and sulfur dioxide (SO2) emissions by 53 percent, down to 2.1 million tons of annual SO2 emissions.[21]

The EPA's proposed standards are projected to save as many as 17,000 lives every year by 2015; prevent up to 120,000 cases of childhood asthma symptoms and 11,000 fewer cases of acute bronchitis among children every year; avoid more than 12,000 emergency room and hospital visits annually; and prevent 850,000 lost work days every year. The monetized benefits from the improved health standards are estimated to be $59 billion to $140 billion annually, compared to annual compliance costs of approximately $10.9 billion. The EPA also projects that the proposed standards will create up to 31,000 short-term construction jobs and 9,000 long-term utility jobs.[22]

Requirements of the new standards include:[21]

  • For all existing and new coal- and oil-fired electric utility steam generating units (EGUs), the proposed standards would establish numerical emission limits for mercury, PM, and HCl.
  • For all existing and new oil-fired EGUs, the proposed toxics rule would establish numerical emission limits for total metals, HCl, and HF.
  • Actions available to power plants to meet the emission limits include wet and dry scrubbers, dry sorbent injection systems, activated carbon injection systems, and baghouses, all part of Maximum Achievable Control Technology (MACT).
  • The proposed standards would establish work practices, instead of numerical emission limits, to limit emissions of organic air toxics, including dioxin/furan, from existing and new coal- and oil-fired power plants.
  • The proposed revisions to the NSPS would include revised numerical EGU emission limits for PM, SO2, and NOX.

Arsenic limits lifted at Wateree Station

On March 8, 2010 it was announced that the South Carolina Department of Health and Environmental Control agreed to eliminate arsenic limits in a wastewater discharge permit for South Carolina Electric & Gas Company's (SCE&G) Wateree Station. SCE&G needs State approval for its coal ash ponds because wastewater from the site runs directly into the Wateree River. The ponds take waste from the company's 40-year-old coal-fired plant. Since the 1990s, high levels of arsenic, a carcinogen, have been found in groundwater and in seepage to the Wateree River from coal ash ponds at the power plant. Sierra Club and other environmental groups are posing to fight the permit on the grounds that arsenic ought not be eliminated.[23]

Heavy metal releases in Kingston coal ash spill higher than initially reported

According to reports filed with the EPA by the Tennessee Valley Authority, the 2008 TVA Kingston Fossil Plant coal ash spill resulted in a discharge of 140,000 pounds of arsenic into the Emory River -- more than twice the reported amount of arsenic discharged into U.S. waterways from all U.S. coal plants in 2007.[24]

According to the Environmental Integrity Project, "The new Toxics Release Inventory (TRI) data submitted to the EPA by TVA also show that the Kingston ash spill deposited nearly 320 tons of vanadium in the Emory River, or more than seven times the total discharge of this toxic pollutant from all power plants in 2007. The Kingston facility singlehandedly discharged more than of chromium, lead, manganese, and nickel into the Emory River last year than reported discharges of those pollutants from the entire U.S. power industry in 2007. The EIP analysis of the new TVA data finds a total of 2.66 million pounds of 10 toxic pollutants – arsenic, barium, chromium, copper, lead, manganese, mercury, nickel, vanadium and zinc. That compares to the much lower 2.04 million pounds of such discharges from all U.S. power plants into surface waters in 2007."[24]

Health and Ecological Impacts from Kingston Coal Ash Spill Pollutants

The following table summarizes the impacts of pollutants released in the TVA Kingston Fossil Plant coal ash spill:[25]

Pollutant Human Health Impacts Ecological Impacts
Arsenic Human carinogen; also linked to cardiovascular and dermal effects, encephalopathy, and periperhal neuropathy Accumulates in freshwater plants and bivalves, where it enters the food supply.
Barium Can cause gastrointestinal disturbances and muscular weakness. Ingesting large amounts, dissolved in water, can change heart rhythm and can cause paralysis and possibly death. Affects development of geminating bacterial spores and has a variety of effects on microorganisms, including inhibition of cellular processes.
Chromium Chromium VI is a known human carcinogen; expusure has also caused stomach tumors in humans and animals. Can make fish more susceptible to infection and damage/accumulate in fish tissues and invertebrates such as snails and worms.
Copper High levels can cause harmful effects such as irritation of the nose , mouth and eyes; diarrhea; stomach cramps; nausea; and even death. Has adverse reproductive, biochemical, physiological, and behavioral effects on aquatic organisms.
Manganese Exposure to high levels can affect the the nervous system; very high levels may impair brain development in children. Nervous system and reproductive effects have been observed in animals after high oral doses.
Mercury High levels can permanently damage the brain and other organisms; can harm developing fetus, causing brain damage, mental retardation, blindness, seizures, and inability to speak. Easily absorbed through organic tissues and membranes; easily bioaccumulates and can concentrate as it progresses up food chains.
Nickel The International Agency for Research on Cancer (IARC) has determined that some nickel compounds are carcinogenic to humans and that metallic nickel may possibly be carcinogenic to humans. Absorption into organisms\' organs and bodies can cause growth defects.
Vanadium Impacts from ingestion unclear; workers who breathed vanadium suffered lung irritation, coughing, wheezing, chest pain, runny nose, and sort throat. Animals that have ingested very large doses have died. High levels in the water of pregnant animals caused minor birth defects.
Zinc Ingesting large doses even for a short time can cause cramps, nausea, and vomiting; inhaling large mounts can cause a short-term disease called metal fume fever. High concentrations in water have been shown to exert adverse reproductive, biochemical, physiological, and behavioral effect5s on a variety of aquatic organisms.

2010: Reports identify coal waste sites exceeding heavy metal levels

On February 24, 2010 Environmental Integrity Project and Earthjustice released a report, "Out of Control: Mounting Damages from Coal Ash Waste Sites" indicating that at least 31 “new damage cases” were not listed by the EPA in its 2010 coal-ash pollution sites. The groups identified the sites by assembling contamination data from state files using “similar criteria” to those sites the EPA had already identified. The 31 identified sites are spread across 14 states, including Delaware (1), Florida (3), Illinois (1), Indiana (2), Maryland (1), Michigan (1), Montana (1), Nevada (1), New Mexico (1), North Carolina (6), Pennsylvania (6), South Carolina (3), Tennessee (2), and West Virginia (2). Arsenic, selenium, and boron were among the dangerous chemicals found to have “migrated off” nearly half of the 31 sites where coal-fired power plants store their coal ash. The report concluded that the EPA must regulate coal ash waste in order to protect the public and the environment from the negative effects of coal waste.[26]

The 2010 EarthJustice, Environmental Integrity Project, and Sierra Club report, "In Harm's Way: Lack of Federal Coal Ash Regulations Endangers Americans and their Environment," identified an additional 39 coal combustion waste (CCW) disposal sites in 21 states that have contaminated groundwater or surface water with toxic metals and other pollutants, based on monitoring data and other information available in state agency files.[27]

When the findings from the two reports are added to the 67 damage cases that the U.S. Environmental Protection Agency (USEPA) acknowledged in 2010, the total number of sites polluted by coal ash or coal scrubber sludge comes to at least 137 in 34 states.[27]



  1. Jeff Goodell, Big Coal: The Dirty Secret Behind America's Energy Future. New York, N.Y.: Houghton-Mifflin, 2006
  2. 2.0 2.1 "Heavy Metals Naturally Present in Coal & Coal Sludge" Sludge Safety Project, accessed November 2009
  3. 3.0 3.1 3.2 3.3 Eilene Toppin Ording,"Heavy Metals and Coal: Carbon Footprint Aside, Coal is not Environmentally Friendly" Suite 101, accessed November 2009
  4. 4.0 4.1 Clean Air Task Force, "Laid to Waste: The Dirty Secret of Combustion Waste from America’s Power Plants", 2000
  5. Neil King and Rebecca Smith,"White House, EPA at Odds Over Coal-Waste Rules", The Wall Street Journal, January 9, 2010.
  6. 6.0 6.1 Sue Sturgis,"Bush administration hid coal ash dumps' true cancer threat," Instituted for Southern Studies, May 8, 2009.
  7. 7.0 7.1 "Green Coal?," Rachel's Environment & Health News, November 6, 2008.
  8. 8.0 8.1 "Fly ash: Culprit at Lafarge? Residue of coal-burning is being examined as possible source of mercury pollution," Times Union, October 26, 2008.
  9. Sue Sturgis, "Coal's ticking timebomb: Could disaster strike a coal ash dump near you?," Institute for Southern Studies, January 2009
  10. 10.0 10.1 10.2 "Heavy Metal Toxicity" Life Extension, accessed November 2009
  11. 11.0 11.1 11.2 11.3 "Lead in Children’s Foods: Frequently Asked Questions" The Environmental Law Foundation Report, accessed July 2010.
  12. “Mercury Emissions from Coal-Fired Power Plants: The Case for Regulatory Action,” Northeast States for Coordinated Air Use Management, October 2003.
  13. "'Fingerprinting' Method Tracks Mercury Emissions From Coal," ScienceDaily, October 9, 2008.
  14. "Mercury Found in Every Fish Tested, Scientists Say," New York Times, August 20, 2009.
  15. "EIP Report: Electric Power Industry "Not Making A Dent" in Dangerous Mercury Pollution, Which Rose at Over Half of the Nation's 50 Dirtiest Power Plants" Environmental Integrity Project, March 17, 2010.
  16. Ash Sunstein AshSunstein.com, accesses March 16, 2010.
  17. "Coal Combustion Residuals - Proposed Rule" EPA, accessed June 2010.
  18. Renee Schoof, "EPA postpones decision that would toughen coal ash rules "http://www.kansascity.com/2010/05/04/1924393/epa-postpones-decision-that-would.html#ixzz0n1E1PsMX" Kansas City Star, May 4, 2010.
  19. Mark Peters, "EPA Proposes Competing Approaches To Regulate Coal-Ash Waste" Wall Street Journal, May 4, 2010.
  20. "New Rules on Coal Ash Will Leave a Giant Loophole for Dumping Waste In Unprotected Mines" Prairie Rivers Network Press Release, May 10, 2010.
  21. 21.0 21.1 21.2 21.3 "Fact Sheet: Proposed Mercury and Air Toxics Standards" EPA, accessed March 2011.
  22. John Walke, "A little background on the EPA’s new mercury and air toxics rule" Grist, March 16, 2011.
  23. "DHEC loosens arsenic limit for SCEandG: Discharge from utility's plant feeds into Wateree River" Sammy Fretwell, RenewableBiz.com, March 8, 2010
  25. Ash Spill 2009128.pdf Comparison of 2008 Kingston Coal Ash Discharges to 2007 Industry Discharges, Environmental Integrity Project fact sheet, December 8, 2009
  26. "Study of coal ash sites finds extensive water contamination" Renee Schoff, Miami Herald, August 26, 2010.
  27. 27.0 27.1 Jeff Stant, "In Harm's Way: Lack of Federal Coal Ash Regulations Endangers Americans and their Environment," EarthJustice, Environmental Integrity Project, and Sierra Club report, August 26, 2010.

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