EPA’s Blind Spot: Hexavalent Chromium in Coal Ash
Coal ash may be the secret source of cancer-causing chromium in your drinking water
EPA’s Blind Spot: Hexavalent Chromium in Coal Ash
Author: Lisa Evans, Earthjustice Contributing Authors: Barb Gottlieb, Physicians for Social Responsibility; Lisa Widawsky, Jeff Stant, Abel Russ, John Dawes, Environmental Integrity Project Environmental Consultant: J. Russell Boulding
February 1, 2011
Hexavalent chromium is again in the headlines. In the 1990s, Erin Brockovich achieved fame by uncovering the presence of extraordinarily high levels of industrial hexavalent chromium contamination in the drinking water of a small desert town ravaged by cancer. Today, attention to the deadly chemical is fueled by new data and extensive scientific research. In December 2010, the Environmental Working Group released a report documenting the cancer-causing chemical in tap water in 31 of 35 cities tested in the United States.1 Days later, on December 31, 2010, the California Office of Environmental Health Hazard Assessment (OEHHA) completed a multi-year, peer- reviewed examination of the oral toxicity of the chemical, involving scientists in both the public and private sectors, and released a ground breaking proposal to establish a public health goal for hexavalent chromium in drinking water of just 0.02 parts per billion (or ug/L), 5,000 times lower than the current federal drinking water standard for total chromium.2
On January 11, 2011, on the heels of these announcements, the U.S. Environmental Protection Agency (EPA) issued new guidelines recommending that public water utilities nationwide test drinking water for hexavalent chromium (Cr(VI)).3 EPA’s swift reaction to the widespread presence of hexavalent chromium in American tap water is laudable. However, EPA’s well-placed concern for protection of public health has a dangerous blind spot. While government regulators express concern for small quantities of the cancer-causing substance in our water, they are ignoring one of the largest sources of the hazardous chemical—coal combustion waste (or coal ash)4 from the nation’s coal burning power plants.
This report documents the connection between coal ash and hexavalent chromium. It reviews the sources, toxicity, and known coal ash dump sites where chromium has been found in groundwater. The report identifies studies of numerous power plants where testing of coal ash leachate found extremely high levels of hexavalent chromium. The report also identifies 28 coal ash disposal sites in 17 states where groundwater was documented to exceed existing federal or state standards for chromium and to exceed by many orders of magnitude the proposed California drinking water goal for hexavalent chromium. These contaminated coal ash dump sites are likely the tip of the iceberg. The threat of drinking water contamination by hexavalent chromium is present in hundreds of communities near unlined coal ash disposal sites across the United States. While the EPA doesn’t need another reason to define coal ash as a hazardous waste, it certainly has one now.
Hexavalent Chromium and Coal Ash: The Deadly Connection
It has long been known that chromium readily leaches from coal ash.5 Chromium, however, occurs primarily in two forms: trivalent chromium, which is an essential nutrient in small amounts, and hexavalent chromium, Cr(IV), which is highly toxic even in small doses. In EPA’s latest report on the hazardous contaminants in coal ash, the agency made two important findings:
Coal ash leaches chromium in amounts that can greatly exceed EPA’s threshold for hazardous waste at 5000 parts per billion (ppb),6 and
The chromium that leaches from coal ash is “nearly 100 percent [hexavalent] Cr(VI).”7
Remarkably, the U.S. Department of Energy (DOE) and the energy industry have also known for years about the aggressive leaching of hexavalent chromium from coal ash. In a 2006 report co-sponsored by DOE, the Electric Power Research Institute (EPRI) found definitively that the chromium that leaches from coal ash (including FGD sludge) is 97– 100 percent hexavalent chromium.8
These findings, buried in government reports, need to see the light of day. Hundreds – maybe thousands – of leaking and unlined coal ash dumps are situated near water supplies. EPA and DOE have demonstrated that the contaminated leachate (the liquid leaking from coal ash landfills and ponds) is often rich in this cancer-causing chemical. Therefore it is imperative that EPA Administrator Lisa Jackson act decisively to protect U.S. communities from this significant source of hexavalent chromium.
Hexavalent Chromium’s Deadly Link to Cancer
In 2008, a two-year study by the U.S. Department of Health and Human Services’ National Toxicology Program (NTP)9 demonstrated that hexavalent chromium in drinking water causes cancer in laboratory animals.10 While it has long been known that hexavalent chromium causes lung cancer when inhaled, the NTP undertook a study of Cr(VI) ingestion following a request from California’s Office of Environmental Health Hazard Assessment (OEHHA). Based on a variety of cancerous oral and intestinal tumors, the NTP study definitively concluded “hexavalent chromium can also cause cancer in animals when administered orally.”11
Furthermore, scientists believe chronic ingestion of minute amounts of Cr(VI) can be harmful. In fact, after an extensive peer-reviewed study, the California Office of Environmental Health Hazard Assessment lowered its original hexavalent chromium draft goal by 66 percent this year to account for the special sensitivity of infants and children to carcinogens. California’s proposed public health goal, 0.02 parts per billion, is a mere 0.02% of the present federal drinking water standard for total chromium. If the current federal drinking water standard (100 parts per billion) is compared to a 100-yard football field, California’s proposed goal for Cr(VI)would be a distance of three-quarters of an inch.
According to EPA’s 2010 draft toxicological review of hexavalent chromium, EPA agrees with the estimate of cancer potency used by California’s Office of Environmental Health Hazard Assessment. California’s Draft Public Health Goal12 and the U.S. EPA Draft Toxicological Review of Hexavalent Chromium13 both use the same cancer potency value for ingested hexavalent chromium of 0.5 (mg/kg-d)-1. Using EPA’s default assumptions for body weight and drinking water ingestion rate, it is possible to estimate the lifetime cancer risk associated with drinking water at the current federal drinking water standard for total chromium of 100 ppb (established in 1991) – the risk is 1.4 in 1,000 people.14 This risk is 140 – 1400 times greater than EPA’s range of acceptable cancer risk (between1 in 100,000 and 1 in 1,000,000 people).15 Clearly, in view of this elevated risk recognized by both EPA and OEHHA, the 1991 federal drinking water standard of 100 ppb for total chromium is not sufficiently protective of human health from ingestion of hexavalent chromium. While a new federal drinking water standard for hexavalent chromium may be higher than California’s proposed goal of 0.02 ppb, this health-protective level, as well as the current federal standard, are used as a comparison to coal ash-contaminated waters in this report.
Ingestion of Hexavalent Chromium Is Missing from EPA’s Coal Ash Risk Assessment
Although the cancer risk associated with Cr(VI) in groundwater is substantial, EPA completely ignored this risk in its proposed coal ash rulemaking. While Cr(VI) was discussed in the preamble to the proposed rule, it was treated as a carcinogen by inhalation only. For purposes of calculating the human health risk by ingestion, Cr(VI) was treated as a non-carcinogen.16 Despite the clear findings of NTP’s 2008 studies, the cancer risk of ingested Cr(VI) was not mentioned once in EPA’s 400-page “Health and Ecological Risk Assessment for Coal Combustion Wastes.”
Coal Ash Dump Sites Are Significant Sources of Hexavalent Chromium
Coal ash can leach deadly quantities of Cr(VI) to drinking water.17 For example, in the 2006 study18 by the Electric Power Research Institute, an organization that vehemently opposes a hazardous designation for coal ash, EPRI tested leachate—liquid collected from wells, ponds or seeps at coal ash dumps—at 29 coal ash landfills and ponds and found hexavalent chromium at hundreds of times the proposed California drinking water goal at 15 coal ash disposal sites. Their findings included three landfills where leachate exceeded the proposed drinking water goal by 5,000 times, with two landfills exceeding that goal by 100,000 and 250,000 times. The location of these potentially deadly dumps is not known, but the high levels of hexavalent chromium at the sites may pose a danger to those living near the landfills. Table A lists the coal ash dump sites where leachate was found containing hexavalent chromium over 5,000 times the proposed California health goal.
Coal Ash Dump Sites Identified by the Electric Power Research Institute with Leachate containing Hexavalent Chromium (Cr(VI))
The access/view the table go to page 5 – http://www.psr.org/assets/pdfs/epas-blind-spot.pdf
In addition, data from known coal ash disposal sites obtained from EPA reports19 and recent studies by Earthjustice, the Environmental Integrity Project (EIP) and the Sierra Club20 make it eminently clear that the threat is widespread and serious. For example, chromium in groundwater contaminated by a coal ash landfill in Ohio reached 1.68 parts per million – a level 84,000 times California’s proposed drinking water goal (if nearly all the chromium measured was hexavalent, as predicted in both EPA’s and EPRI’s reports). Table B lists 28 coal ash dump sites in 17 states where coal ash contaminated groundwater was found to contain chromium at levels exceeding the current federal drinking water standard (100 ppb) or an applicable state standard (50 ppb for groundwater in North Carolina). Often EPA did not provide a specific value for the chromium found in groundwater wells, but simply indicated that it was greater than the federal standard of 100 ppb. These chromium concentrations, if 100 percent hexavalent chromium, represent a level 5,000 times higher than the proposed California goal. In Table B, all chromium is assumed to be hexavalent chromium, a premise supported by the studies conducted by EPA, DOE and EPRI. In addition, most of the coal ash ponds, landfills and fill sites listed below are unlined – a factor that greatly increases the danger to neighboring communities. Lastly, while many of the sites below have undergone some form of remediation under Superfund or state authorities, in most cases the contamination has been left in place, and there may be little attempt to monitor its migration offsite to protect well users from harmful exposure to hexavalent chromium or other toxic metals commonly found in coal ash leachate.
Uniontown, Ohio: A Coal Ash Site Where Health May be Endangered
The Industrial Excess Landfill, near Uniontown, Ohio is an example of the kind of site that may be posing a threat to the surrounding community from contamination of drinking water with hexavalent chromium. The landfill is a Superfund site surrounded on three sides by residential neighborhoods. Roughly one million tons of coal ash were dumped at the landfill in the 1960s. The landfill was closed in 1980, and EPA listed it as a Superfund site in 1986. Groundwater monitoring since then has shown chromium concentrations to be increasing to very dangerous levels. Systematic groundwater monitoring began in 1987, and chromium was detected at concentrations up to 180 ppb in off-site wells. Sampling in the early 1990s found concentrations of chromium over 100 ppb in eight monitoring wells, with concentrations up to 739 ppb. Monitoring through 2001 detected chromium at up to 1,680 ppb in off-site wells located in or near residential areas- over 15 times the federal drinking water standard. Residents report many incidences of cancer in the affected neighborhoods.
Despite alarming evidence of off-site groundwater contamination with heavy metals, including chromium, metals monitoring was phased out around 2001, and remedial actions stopped in 2005. And yet the potential for human exposure to this contamination is very high—there are almost 4,000 private drinking water wells within two miles of the site, and about 90 wells within 1,500 feet. Some homes have been provided with alternative water supplies, but many have not. The cancer risk associated with drinking water having chromium concentrations over 100 ppb is greater than 1 in 1,000. The risk associated with the highest known concentration, 1,680 ppb, would be greater than 1 in 50. Furthermore, this cancer risk would be amplified by the presence of arsenic and other carcinogens in the coal ash contaminant plume.
EPA Laboratory Testing of Coal Ash Reveals Dramatic Chromium Leaching
EPA also found that leachate produced in the laboratory from coal ash at a variety of plants contained sky-high chromium. In a 2009 report, EPA tested coal ash leachate by obtaining waste from numerous operating power plants.21 EPA found that many ashes and sludges produce leachate extremely rich in chromium. The table below provides EPA’s results from five plants. These results represent the highest level of chromium in leachate determined by EPA lab tests. Unlike the EPRI data in Table A and the groundwater and surface water data in Table B, the results below were not field samples. However, EPA used a leach test that mimics field conditions in order to determine the range of chromium that would leach from coal ash disposed under real-world conditions. If this leachate were seeping or leaking into groundwater from a landfill or pond, it could threaten drinking water wells and human health. While the public is not likely to be exposed to coal ash leachate at full strength, leachate this rich in chromium, even if it is diluted as it flows through groundwater, can still pose a significant hazard when it reaches drinking water wells.
How much chromium is released by U.S. Coal-Fired Power Plants each year?
The amount of chromium released by our nation’s coal-burning power plants dwarfs all other industrial sources. According to EPA’s Toxic Release Inventory, the electric power industry dumps over ten million pounds of chromium and chromium compounds in on-and off-site disposal sites each year. Between 2000 and 2009, over 116 million pounds of chromium and chromium compounds were released from coal-fired power plants. The overwhelming majority of this chromium ends up in unlined or inadequately lined coal ash landfills, ponds, and mines. See Table D.
In 2009, the electric power industry reported 10.6 million pounds of chromium and chromium compounds were released to the environment (10.1 million of which was dumped in disposal sites). These 10.6 million pounds represent 24 percent of the total chromium and chromium compounds released by all industries in 2009. See Chart, below. In fact, the top ten chromium-releasing coal-fired power plants alone released almost 1.8 million pounds of chromium and chromium compounds in 2009, and each of these has at least one – if not, more than one – unlined coal ash disposal unit. Despite the obvious significance of this source of chromium, coal-fired power plants are rarely tagged as a source of hexavalent chromium.
As the Air Gets Cleaner, the Threat to Drinking Water Increases
EPA has found that as power plants reduce their emissions of nitrogen oxides (NOX) by employing pollution controls at the power plant stacks, more hexavalent chromium is found in the flue gas desulfurization (FGD) sludge.22 According to EPA, over half of the U.S. coal-fired capacity is projected to be equipped with SCR and/or FGD technology by 2020.23 In fact, EPA anticipates an increase of approximately 16% in scrubbed units by 2015.24 Thus as the Clean Air Act requires more and more plants to install pollution controls, we may experience a much greater threat to our drinking water from hexavalent chromium if disposal of the increased volume of FGD sludge is not properly controlled.
EPA Must Determine that Coal Ash is Hazardous
Although coal ash readily leaches hexavalent chromium, the waste is currently not federally regulated and is routinely dumped in unlined ponds and pits and used as construction fill without restriction. EPA must keep this dangerous chemical out of our water – by regulating coal ash as a hazardous waste, thereby requiring its disposal in safe, secure landfills.
In addition, EPA should immediately investigate the ponds, landfills and fill sites identified in this report to determine if public health is being threatened by exposure to hexavalent chromium, including:
The three landfills identified in the DOE/EPRI report where Cr(VI) levels in leachate exceed proposed drinking water goals by thousands to hundreds of thousands of times (Table A);
The 28 landfills, ponds and fill sites where groundwater has been contaminated with chromium over the current federal drinking water standard (Table B) and thousands of times over the proposed drinking water goal (Table B); and
The disposal sites at the five plants where EPA’s laboratory tests document the potential for dangerous levels of Cr(VI) to leach from ash and sludge (Table C).
EPA must conduct these investigations to ensure that highly contaminated leachate from these coal ash disposal sites is not leaking into drinking water and threatening human health. However, it is important to understand that these sites do not represent the universe of coal ash sites that have contaminated groundwater with chromium. Most coal ash disposal sites in the U.S. is are not monitored sufficiently to determine whether they are contaminating groundwater, and certainly very few coal ash sites are monitored for hexavalent chromium at all. Ultimately only the regulation of coal ash under subtitle C of the Resource Conservation and Recovery Act will ensure that these disposal sites, as well as every coal ash dump in the nation, are constructed securely and monitored sufficiently to keep hexavalent chromium out of our drinking water.
To access the tables, sources, and additional information click below.
EPA’s Blind Spot: Hexavalent Chromium in Coal Ash
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