Aberdeen Proving Ground said yesterday that its water-treatment plant north of Aberdeen appears to be the source of low levels of chloroform, a suspected carcinogen, in nearby private wells.
Army officials said that if the treatment plant is confirmed to be the source, the proving ground may have to supply bottled water or in-home filter systems to at least six homes.
"We'll find the leak and fix it," said Howard Galliford, an environmental official at the proving ground.
Army officials say fixing a leak at the water-treatment plant could require shutting it for a day or more. The plant is the only source of drinking water for the Aberdeen area of the proving ground.
In the event of a shutdown, the Army would have to ask Harford County for water, said Ken Stachiw, chief of the proving ground's environmental management division.
But, until at least May 15, the proving ground is supplying up to 900,000 gallons of water a day to the county, because the installation has acknowledged that an old firefighter training area is a source of low levels of trichloroethylene, another suspected carcinogen, in the county's Perryman well field. The county has had to shut down a major supply well until a treatment system can be installed.
The county Health Department, in a recent letter to the Maryland Department of the Environment on the chloroform issue, said officials were "concerned as to the source of the pollution and whether these levels in the ground water could rise."
As much as 40 parts per billion of chloroform recently has been
found in the six wells. Federal standards allow no more than 100 parts per billion of the chemical and related substances -- known collectively as trihalomethanes -- in drinking water.
The Army and county health officials said the chloroform probably is being formed as a byproduct of the chlorination process at the treatment plant.
Although health officials and the proving ground began discussing the chloroform issue just in the past month, county records indicate the chemical was found in at least one well as early as 1986.
A resident -- who like her neighbors asked that her name not be published because she feared it would cause her home value to drop -- said she bought bottled water for two years in the late 1980s, then installed a filter because she was concerned about the health of her young children.
The most recent well testing, completed within the past two weeks, was prompted by a complaint from a resident, county records show.