By SHAILA DEWAN
Published: January 9, 2009
Waste from a pond at an Alabama coal-fired power plant run by the Tennessee Valley Authority escaped Friday into a Tennessee River tributary.
The accident occurred less than three weeks after a rupture in a similar pond at another T.V.A. plant spilled more than a billion gallons of coal ash over 300 acres in East Tennessee.
The overflow in Alabama, at the Widows Creek Fossil Plant in the northeastern corner of the state, was much smaller, officials said.
Up to 10,000 gallons of slurry spilled, said Scott Hughes, a spokesman for the Alabama Department of Environmental Management, who cautioned that the figure was preliminary.
Mr. Hughes said investigators had not documented any negative impact on aquatic life and did not expect any contamination of drinking water.
John Moulton, a spokesman for the T.V.A., said the problem began when solid material slid into the slurry in the pond, driving water through a disused pipe. The pipe led to an adjacent settling pond, which then overflowed into Widows Creek, a Tennessee River tributary, Mr. Moulton said.
John Wathen, an environmental advocate, flew over the site Friday and said that Widows Creek was inundated with an ashlike substance and that a “mix line” was visible where it met the clearer water of the river.
Referring to the earlier spill, at the Kingston Fossil Plant in Tennessee, Mr. Wathen added: “This is not as bad as Kingston, but it’s worse than T.V.A. is acknowledging. This is two failures by T.V.A. in one month’s time, both in the Tennessee River. Both are potential problems for downstream water intake.”
Friday’s spill involved coal combustion waste different from that in the earlier one.
In Tennessee, what spilled was largely fly ash, a byproduct known to contain toxic metals like arsenic, lead and mercury. That spill occurred on Dec. 22 when an earthen retaining wall gave way.
In Alabama, the spill was from a gypsum pond, Mr. Moulton said. Some methods of cleaning toxic substances from coal plant emissions produce a slurry that is stored in a pond until the formation of crystals of gypsum, a material used to make drywall.
Though gypsum slurry does contain contaminants, it is less toxic than fly ash, studies by the Environmental Protection Agency show. Still, tests of water that has leached from gypsum can yield levels of boron, cadmium, molybdenum and selenium that exceed safety standards. These contaminants can cause cancer and reproductive and neurological problems in humans, and selenium is particularly harmful to wildlife.
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