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Welcome to PSR's Environmental Health Policy Institute, where we ask questions -- then we ask the experts to answer them. Join us as physicians, health professionals, and environmental health experts share their ideas, inspiration, and analysis about toxic chemicals and environmental health policy.


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EPA Relies on Inadequate Test to Assess Dangerous Leaching

Posted on March 2, 2012

By Eric Schaeffer

This essay is in response to: How toxic is coal ash, the waste material left after coal is burned? How does it come to poison the waters and dust the land in communities across the nation? And what can be done to prevent further toxic contamination?

We take for granted our easy access to the electricity that lights up our homes, charges our computers and cellphones, and keeps factories and businesses humming. But we pay a high price in human health for that convenience for the power we use from coal plants. The good news is that after decades of regulation and court battles, most of those plants are gradually reducing emissions that contribute to thousands of premature deaths every year. The bad news is that the contaminants removed from power plant smokestacks by Clean Air Act pollution controls are being disposed of in coal ash – and finding their way into aquifers or rivers that are a primary source of drinking water. These risks have spread in part because EPA and state agencies have for decades relied on the wrong test to measure the likelihood that these pollutants will leach from coal ash and into the groundwater underneath. 

Although concentrations vary depending on mine source, coal is naturally high in arsenic and other toxic metals that are released when that coal is burned. These metal compounds cannot be destroyed during combustion, and either exit the stack as air pollution, or become further concentrated in the ash and sludge byproducts of emission controls. About 70 million tons of this residue was dumped in ponds, landfills, or “reclaimed” mines in 2010. 

Over time, and triggered by changes in the pH of the water that comes into contact with these wastes, heavy metal compounds are released and drain into the aquifers, creeks, and wetlands that abut these dumpsites. Consistent monitoring data is scarce, but our review of state files has found, in monitoring wells downgradient of many disposal sites, concentrations of arsenic, boron, chromium, lead, manganese, selenium, and other pollutants at levels far above EPA drinking water standards or health advisories.

How did this happen? Too much of this waste was dumped onto permeable soil too close to wetlands or the groundwater table, without liners or other basic technologies to prevent leaks. Meanwhile, despite the accumulating evidence of damage, the US Environmental Protection Agency (EPA) has failed to exercise its authority under the Resource Conservation and Recovery Act to require these common-sense safeguards. And for too many years, both industry and government have relied upon the “Toxicity Characteristic Leaching Protocol” (TCLP) to help justify mismanagement or inaction. 

The TCLP is a test developed by EPA in 1990 to measure the tendency of metals and other pollutants to leach into the environment from household garbage. The very next year, the Environmental Engineering Committee of the EPA’s Science Advisory Board warned that this short-term batch test applied under fixed conditions (i.e., a defined pH) was inadequate to evaluate the impacts of more complex conditions.  Specifically, it failed to take account of the very different characteristics and disposal conditions that typify the real-world disposal of industrial wastes. Using an analogy PSR members will appreciate, the Committee added that, “no physician would diagnose on the basis of one test showing only one aspect of the problem,” and recommended development of test methods based on the real world. 

In 1999, a second SAB/EEC report criticized EPA’s continued reliance on the TCLP, reminding the Agency that “a leaching protocol should be both accurate and reasonably related to conditions governing leachability under actual waste disposal conditions.” After noting the Agency’s failure to address its 1991 recommendations, the committee itemized the shortcomings of the TCLP test. These included assuming a 2:1 liquid-to-solid ratio, which is unrelated to actual site conditions; relying on a low pH value, an assumption that will not predict leaching caused by alkalinity; and a short test period (18 hours) that cannot predict the “slow release” of contaminants over time periods of years, not hours.  These factors are particularly relevant to coal ash, which is often very alkaline, is mixed with other wastes and liquids at disposal sites that can be much “wetter” than municipal landfills, and is characterized by leach rates that peak after a decade or more. 

Not surprisingly, in a 2006 report, the National Research Council found the TCLP especially unsuited to coal ash. The report recommended federal standards be established for minefilling with this material, and urged EPA to develop a more suitable alternative. 

What has the EPA done with this advice from some of the nation’s top experts in the field? Nearly ten years ago, the agency began experimenting with a new protocol developed by Vanderbilt University scientists to test the mobility of coal waste leachates under a much wider range of pH conditions. The Vanderbilt test results showed much higher leachate concentrations of some pollutants – like arsenic and selenium – than did the TCLP. But it is unclear what the EPA is going to do with this research. Meanwhile, the coal industry and state agencies continue to base claims about the “safety” of coal ash on TCLP tests that EPA’s scientific advisors and the NRC have said do not work for most industrial wastes. 

EPA’s failure to keep up with science has hurt communities that live near coal ash sites, who are still waiting for the safe disposal standards that the Obama Administration promised more than three years ago. EPA is still struggling to get those rules out, confounded by election-year politics and Congressional opposition. But that effort is not helped when the coal lobby can advertise that its waste is “safe,” using a test method that does not work but is still sanctioned by EPA.

President Obama has said that our environmental decisions ought to be guided by law and science. EPA can honor that commitment by adopting a test for coal ash that is scientifically accurate – and that will finally tell the truth about this huge, unregulated and toxic waste stream.

PSR invites concerned readers to sign our petition urging President Obama to direct the EPA to issue strong coal ash protections.


Ingay Balnacs said ..

We elected Congress to make our laws, not EPA!

March 7, 2017
Ant King said ..

Strain at a gnat and swallow a camel. EPAs finest. EPA needs dismantled and replaced with a congressional committee that insures that all laws go through Congress. NOW.

March 7, 2017

Comments closed.