The Army plans to meet with residents Tuesday night in Baltimore County to lay out a nearly $6 million plan to clean up groundwater on an Aberdeen Proving Ground peninsula that is fouled by a cancer-causing solvent.
Graces Quarters, a restricted area on the Gunpowder River and Dundee Creek - adjacent to the Hammerman Area of Gunpowder Falls State Park - was a testing area for chemical warfare agents and decontaminants in the 1950s and 1960s.
Carroll Island to the south was an open-air test site for blistering, nerve and other chemical agents.
The aquifer is not a drinking-water source for any off-post communities, researchers and regulators say, and U.S. Geological Survey tests show that the water flows away from private wells farther inland.
But the highest levels of the solvent are 7,000 times as high as what the Environmental Protection Agency and the Maryland Department of the Environment say are acceptable.
"I'm glad they're doing something about it and not just walking away," said University of Maryland toxicologist Cal Baier-Anderson, who works with the community on environmental cleanup issues at APG.
The Army has looked at a variety of cleanup strategies that could cost from $400,000 to $14 million. The method they have chosen - using vitamin B-12 and a citrate compound - is expected to cost about $5.7 million and take several decades to eradicate high solvent levels.
"In general, the community likes pump-and-treat better, but no one is drinking the water right now," Baier-Anderson said, referring to an alternative that would cost up to $9.4 million. "From an economic point of view, that's a lot of money to put into an aquifer no one is drinking."
The B-12 method is unconventional, said Don Green, an environmental scientist who piloted the program previously at APG with Canadian researchers.
But at APG, which is one of the most complex contamination sites in the country, cutting-edge environmental technologies are often tried first - including trees that drink up and break down contaminants, and honeybees and fish that monitor toxins.
"We think this is a good place to use this technology," said Frank Vavra of the EPA, who works on APG issues. "Right now, there is no risk to the ecology; there is no risk to the public."
Much of the 72,000-acre installation falls under the EPA's Superfund program. Graces Quarters is one of several national priority list sites.
The base has tested battlefield weaponry and equipment since World War I, and its toxic legacy includes millions of rounds of unexploded ordnance and a chemical weapons stockpile.
Graces Quarters' groundwater is contaminated with a stubborn solvent used to clean blistering and nerve agents off airplanes, vehicles and other battlefield equipment during tests.
"A lot of that stuff was allowed to run off in the ground. They would just spray it on," Green said.
According to Green, the cleanup method involves mixing vitamin B-12 and titanium citrate, creating a solution that begins to break down the highly chlorinated solvent and encourages bacteria growth.
The B-12 solution is dispersed in the groundwater through a recirculating well, where the solvent begins to react and degrade in a few days. Over a period of years, the bacteria consume the solvent reaction leftovers, he said.
Graces Quarters' sandy aquifer on the 414-acre peninsula on the northern Chesapeake Bay is contained by a thick layer of clay on the inland side, said Frederick J. Tenbus, a hydrologist with the U.S. Geological Survey.
"It's going to stay there," he said of the groundwater.
Vavra said that as the groundwater flows south to the end of the peninsula, it "is moving very, very slowly. ... It could be up to 100 years before the contamination reaches the marshes."
"This is a long-term cleanup, and we have time to do that," Green said.
He said a $4.6 million project to shore up about a mile of shoreline on Graces Quarters and Carroll Island is well under way. Carroll Island work is 60 percent complete, and Graces Quarters work is set to begin in the winter.
Baier-Anderson said the community has raised concerns in the past about the B-12 cleanup because the pesticide tolcide is used periodically to clean bacteria buildup on well drains.
She said some members of the Aberdeen Proving Ground Superfund Citizens Coalition also expressed concerns that the extent of the solvent's spread may not be known and that it might extend to other aquifers, including some that run under the bay to the Eastern Shore.
But Tenbus, of the U.S. Geological Survey, said that Eastern Shore aquifers tend to pull from the bay's surface waters first and that the combination of that plentiful supply, plus the complex layers beneath the bay made such a water-migration theory implausible.
When the aquifer's health is restored, it could open the way to use of the peninsula.
"The Army has no plans to turn the land over to residential use, but it's prime real estate," he said of the peninsula overlooking the river and bay. "I would not be surprised to see in the long term that it would be part of a base-closure action."
A public meeting will be held at 6:30 p.m. Tuesday at Marshy Point Nature Center, 7130 Marshy Point Road in Chase. 410-278-1147.