EPA Relies on Inadequate Test to Assess Dangerous Leaching
March 2, 2012
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.