>>  Last December in Eastern Tennessee, a slurry pond full of coal ash burst its banks and sent a six-foot wave of black sludge across the Emery River, sweeping two houses off their foundations.  Plumes of ash floated downstream, settling thousands of tons of muck on the river bottom.  Researchers from Appalachian State University took samples two miles from the spill.

>>  I would say [inaudible] there so the entire ecosystem is coated in ash, which means no oxygen is getting to the organisms that are covered in ash.  It’s completely anoxic.  It’s a dead ecosystem.

>>  The slurry pond is part of the Kingston Power Plant operated by the TVA, the Tennessee Valley Authority.

>>  Let me cite that this is not a time when TVA holds its head high, but we won’t hang our head either because that won’t get the job done.  I’m here to tell you we’ll clean it up.

>>  A billion gallons of slurry poured out of the pond, thirty times more than the Exxon Valdez oil spill in Alaska and three times more than the coal waste that spilled into the Big Sandy River eight years ago in Kentucky, wiping out fish populations for 100 miles.  There are some 300 wet dumps like this in the United States and every year utilities add 20 million more tons of coal ash to these ponds.  The TVA has stored its waste in three ponds at the Kingston Plant for 50 years.  Retention ponds look like giant rice paddies from the air.  Their walls and bottoms are made of dirt and can leak into nearby rivers.  In 2007, the Environmental Protection Agency estimated hazardous chemicals were leaking into groundwater at 67 coal plants, most of them older and located in the southeast.  Coal companies and utilities have lobbied hard to avoid regulation of slurry ponds, but congress now seems ready to act to make sure ruptures like this don't happen again.  Meanwhile, federal and state agencies are monitoring water around the Kingston spill.  They report water is safe to drink, but independent scientists say water samples near the spill contained levels of arsenic up to 300 times higher than EPA standard. 

>>  We know that arsenic at those levels is certainly a potential risk for causing cancer of the bladder, the kidneys, the liver, the lungs, the prostate and skin.

>>  The TVA has built stone dams to block the sludge from migrating further downstream but a lot of it already has.  Scientist say tons of arsenic spilled into the river and much of it will dissolve before TVA can recover it by dredging, contaminating drinking water for more than a million people who live downstream.  For Assignment Earth, I’m Gary Strieker.