Army to start cleanup of tainted well field

January 31, 1993|By Bruce Re | Bruce Re,id Staff Writer

At the hottest environmental hot spot on Aberdeen Proving Ground, a couple of derelict planes lie shrouded by two acres of weeds and locust trees. The most apparent scar is a pit, about the size of a backyard swimming pool, filled with several inches of black oil and water.

From this pit and two others, now overgrown with weeds, a suspected carcinogen has flowed more than a mile into Harford County's underground Perryman well field, which supplies drinking water to 12,000 homes and businesses.

The presence of trichloroethylene, or TCE, a common industrial solvent, already has forced the shutdown of one of eight Harford County wells.

In a few weeks, the Army will begin digging out 4,000 tons ofoil-soaked soil from the unlined pits, once used for igniting practice fires to train firefighters from the proving ground and volunteer companies from Baltimore, Cecil and Harford counties.

The excavation will mark the beginning of a cleanup that could take decades and is expected to cost at least $11.5 million.

Last month, the Army confirmed that small amounts of TCE were seeping from the old firefighter-training area near the proving ground's northern border to part of the county well field 1 1/2 miles to the southwest.

Naren Desai, an environmental engineer for the proving ground, and others believe that waste TCE from motor pool operations and other activities on the proving ground was mixed with oil.

The training area operated from the early 1960s until 1989. In April 1991, the Army replaced it with a new facility that has environmental safeguards to prevent ground water contamination.

The proving ground expects to complete negotiations tomorrow on the purchase of a carbon filter system to prevent more TCE from getting into the county wells. The Army hopes to install the system by April 15, at a cost of up to $800,000, Mr. Desai said.

Once the filter system is installed, the county can resume pumping from the closed well.

The Army, meanwhile, is supplying up to 900,000 gallons of water daily to the county from the post's two treatment plants.

Once the Army determines the extent of TCE contamination around the training area, it expects to begin pumping and treating ground water at the site -- a process that could continue for 30 years.

"We might pump until the cows come home," Mr. Desai said.

The proving ground, a major weapons-testing and research installation since it opened in 1917, has been found in the past decade to have extensive areas of underground chemical contamination.

But the Army has been saying for years that the contaminated ground water was moving east, toward the Chesapeake Bay and away from populated areas.

The recent discovery marks the first time in the proving ground's history that the Army has found that it has introduced a toxic chemical into a public drinking-water supply. Recent Army studies conclude that because the county is withdrawing millions of gallons of water daily at its Perryman well field, the TCE from the firefighter-training area is being pulled westward.

"Certainly, the wells have an influence on the ground water flow," said Paul Miller, a geo-technical engineer from the Army Corps of Engineers' Waterways Experiment Station in Vicksburg, Miss., who is advising the proving ground on the cleanup.

Officials with the Army, as well as county and state agencies, said the latest tests, conducted Jan. 13, confirm that the water from the seven remaining open county wells is safe to drink.

Drinking water from the wells contains 1.6 parts TCE per billion, well below the federal safety standard of 5 parts per billion.

Levels of TCE in untreated water from two of the eight county wells have, at times, slightly exceeded the safety standard.

dTC The well that closed early last month had shown TCE concentrations as high as 8 parts per billion.

Tests this month of an adjacent well showed TCE concentrations of 7.6 parts per billion.

But higher concentrations in those individual wells pose no health threat because water from all the wells is mixed and

treated before being piped to residents, county officials say.

Although the proving ground is paying the entire cleanup bill, Army officials have said that there may be other sources of the TCE outside thepost. While not identifying possible culprits, the Army officials accuse the county of not looking hard enough to find TCE sources.

"We appear to be responsible for some of it," said John T. Paul Jr., an environmental protection specialist at the proving ground.

"The contamination is not coming from our side of the fence," said William T. Baker Jr., Harford's public works chief.

"The volume and quantity [of TCE] has to be coming from a major source, like the fire-training area."

Mr. Baker said the county surveyed all businesses and wells last year that could be sources and found only a trace amount of TCE at one small business several miles north of the county well field.

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