Wednesday, January 28, 2009


The results from Duke University are in. Here they are.

FOR IMMEDIATE RELEASE: Wednesday, Jan. 28, 2009

CONTACT: Tim Lucas
(919) 613-8084


Note to editors: Avner Vengosh can be reached at (919) 681-8050 or Photos of the research area can be viewed at

DURHAM, N.C. -- A report by Duke University scientists who analyzed
water and ash samples from last month's coal sludge spill in eastern
Tennessee concludes that "exposure to radium- and arsenic-containing
particulates in the ash could have severe health implications" in the
affected areas.

"Our radioactive measurements of solid ash samples from Tennessee
suggests the ash has radiation levels above those reported by the
Environmental Protection Agency (EPA) for typical coal ash," said Avner
Vengosh, associate professor of earth and ocean sciences at Duke's
Nicholas School of the Environment. "Preventing the formation of
airborne particulate matter from the ash that was released to the
environment seems essential for reducing possible health impacts."

More than a billion gallons of sludge coal waste spilled from a holding
facility at the Tennessee Valley Authority's Kingston coal-burning power
plant on Dec. 22. The ash-laden waste flooded more than 400 surrounding
acres and spilled into a tributary of the Emory River, which converges
with the Clinch River and flows into the Tennessee River, a major source
of drinking water for many communities in the region. The spill was so
large it partly dammed the tributary of the Emory River, turning it into
a standing pond.

Vengosh's team found that the combined content of radium-228 and
radium-226 - the two long-lived isotopes of radium - in the solid ash
samples they collected from the TVA spill measured about 8 picocuries
per gram. That's higher than the average 5-6 picocuries per gram
reported by the EPA in most bottom and fly ash samples. The curie is a
standard measure of the intensity of radioactivity.

Radium is a naturally occurring radioactive element that decays from
uranium and thorium elements in coal. When the coal is burned, it is
concentrated in the ash. The EPA classifies radium as a Group-A
carcinogenic material, which means exposure to it could cause cancer.

Water samples collected and analyzed by Vengosh and Duke graduate
student Laura Ruhl found high levels of arsenic, measuring 95 parts per
billion, in water from the dammed tributary where coal ash has
accumulated. Only low concentrations were found in the Emory and Clinch
rivers. The EPA has set the arsenic standard for safe public drinking
water at 10 parts per billion.

Arsenic is a toxic metal that can occur naturally in the environment or
as a by-product of some agricultural and industrial activities.
According to the EPA, the effects of long-term chronic exposure to
arsenic can include increased risk of certain types of cancer, as well
as skin damage and circulatory problems.

"The good news is, we detected only trace amounts of arsenic in waters
beyond the dammed tributary," Vengosh said. "The data suggests that in
less than three weeks since the spill, river flow has diluted the
arsenic content. The river is clean, but the water from areas like the
dammed tributary, where the coal ash has accumulated, still contains
high arsenic levels."

Vengosh is an internationally cited expert on the chemistry of
radioactive elements in surface and ground waters. He has conducted
extensive research on radon and radium contaminants in the ground waters
of western North Carolina and the Middle East.

He and Ruhl collected the water and solid ash samples at sites affected
by the TVA spill on Jan. 9. Duke research scientist Gary Dwyer analyzed
the water samples for trace metal content using inductively coupled
plasma mass spectrometry. Following preliminary analysis, the solid ash
samples were incubated and underwent more detailed analysis of their
radioactive content using gamma spectrometry.

Vengosh's team collected the samples from the TVA spill after being
contacted by United Mountain Defense, a nonprofit environmental group
based in Tennessee. The Duke researchers received no funding from the
group or any other external party. All funding was provided by the
Nicholas School, Vengosh said, "to maintain total impartiality in our

"The TVA spill is one of the largest events of its kind in U.S. history.
It raises questions concerning the safety of storing coal ash and the
potential effects of coal ash on environmental and human health,"
Vengosh said. "We hope our analysis will help provide some answers."


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