Three decades into a nightmare environmental cleanup at the Anniston Army Depot, Army officials are giving one last shot at figuring out how to defuse a potential toxic time bomb: a 27-million-pound plume of solvent waste, called trichloroethylene, leaking into the groundwater that feeds Coldwater Spring, Anniston's main source of drinking water.
The risk of someone getting sick in a TCE hot spot is similar to other diminutively dicey endeavors folks face every day, such as riding in an airplane. The threat to one person is microscopically small, and even when multiplied by millions of people over several decades, the risk is still small. But at some point, the numbers could catch up to someone somewhere. And you don't want that someone to be you, especially when the threat is so avoidable.
The Army recently has hired a consultant who will perform one last study that will finally establish whether cleaning up the depot's mess even is possible. If it's not, the threat will linger, probably for centuries.
Since 1978, the Army has spent millions of dollars to dig it up, suck it out of the groundwater with pumps and break it up with hydrogen peroxide injected up to 25 feet into the earth. The Army's efforts have removed tons of contaminated water and clay, most notably in areas on the depot where workers dumped the acid-like waste into unlined ponds and trenches for decades.
If some other type of waste were to blame, that might have been the end of the story. But the Anniston Army Depot is dealing with TCE, a pernicious pollutant that is heavier than water and tends to settle in hard-to-find pockets deep beneath the ground.
At the behest of state and federal regulators, the Army has taken steps to ensure that its workers and people living around the installation are protected from TCE exposure.
The Army spent $1.6 million in 2005 to install new equipment at the Coldwater Spring water-treatment plant to scour TCE out of the water. The contaminant's concentration immediately plummeted from 3-4 parts per billion to below detectable levels in the finished water.
The Army also tests more than 40 private wells used for drinking water near the southern boundary of the depot. None of the wells ever has posted a drinking water violation, except for one used to refill a commercial catfish pond. The Army bought that property last year for $185,000.
As for the depot's work force, required indoor air tests show TCE vapors at concentrations well below the federal standard of 100 parts per million.
But there's no telling where the contamination might pop up from its underground hiding spots or at what concentration. "You don't know where it's coming from so you don't know where to clean," said Lucius Burton with the Anniston watchdog group, Community Against Pollution.
Despite recent advances in cleanup technology, no available method is ideally suited to getting rid of the remaining TCE. An Army contractor estimated in 2006 that it would take 110 to 3,600 years to make the rest of the tainted groundwater beneath the depot acceptable under the federal drinking standard, depending on which cleanup alternative the Army chooses.
The report concluded that a full cleanup within 100 years - a magic number in this particular business - would be "technically impracticable." Too much TCE has seeped into the bedrock, where it is virtually inaccessible to scrubbing systems, the environmental consulting firm Malcolm Pirnie wrote.
Despite that conclusion, the Environmental Protection Agency and the Alabama Department of Environmental Management have asked the Army to plow ahead with one final "feasibility" study. The marching orders are to explore whether any technology exists that will clean up the most troublesome portion of the remaining blob of TCE in a reasonable timeframe.
Full Story: http://www.annistonstar.com/showcase/2008/as-open-0831-0-8h30x3031.htm
