The federal Environmental Protection Agency plans tests on water wells at the Perryman field, which supply half of the drinking water used by Harford's 24,000 water customers, to help the county determine the source of contaminants found in two wells.
In addition, the County Council voted last week to delay spending $200,000 to drill a new well at Perryman until geological tests have been completed in the area. Those tests have not been scheduled because the council must approve money to pay for them.
Last month, Harford administrators confirmed that trichloroethylene, a suspected carcinogen also known as TCE, had been found in two of the county's eight water-producing wells. The chemical was once widely used in paint, paint thinner, cleaning agents and anesthetics.
County administrators have said the treated water that reaches Harford's public water customers is considered safe because the amount of TCE found in the final product is less than the Environmental Protection Agency's limit of five parts per billion.
"The mere presence of TCE shows there is a significant quantity of pollutant, and we don't know where it's coming from yet. I believe it's worth doing," Steven Hirsh, remedial project manager for an EPA Superfund cleanup site at the Aberdeen Providing Ground, told the county council last week.
Hirsh, who traveled from Philadelphia to attend the meeting at the request of Councilwoman Theresa M. Pierno, D-District C, said he believes the treated water used by customers is safe.
He commended the county for performing monthly tests on the wells. The EPA requires only quarterly tests when pollutants are found.
Hirsh told the County Council Tuesday that he wants to conduct tests on all eight wells because he is concerned that the source of the pollution might be Aberdeen Proving Ground. The EPA tests on the Perryman wells will be compared with tests conducted on nearby monitoring wells at APG. TCE was found in the those wells, Hirsch said.
The council has yet to act on a Department of Public Works proposal to spend $450,000 for the geological studies and to design an aeration system or filter for cleaning contaminated water in the wells.
DPW administrators testified at a public hearing on the proposal two weeks ago that the well they propose drilling would be a standby well in case any of the other eight -- which now pump 22 to 24 hours a day -- break down.
When pressed by council members, DPW administrators admitted that the well, if found free of contaminants, could replace the one in which the highest level of TCE was found.
"The reason they want to put a new well there is yield," said Hirsh in a follow-up telephone interview Wednesday. "That one well yields as much as the rest of the field essentially. Without a geological study, I see no reason why we'd make an assumption that water in a new well tapping into the same area would be different. It's possible, of course."
Hirsh's testimony clearly surprised some council members, who were further shocked when he mentioned a 1984 county Health Department press release that announced that pollutants had been found at two wells at Perryman.
Hirsh said the chemicals found in 1984 were different from the one found by DPW in tests in 1990 and again in late 1991. He also noted that different wells were affected.
Baker said the chemicals found at two of the Perryman wells in 1984 were derivatives of gasoline that dissipated on their own.
"It was an isolated incident. This is not new news," said Baker. "The problem went away by itself. We never found out why or where it was coming from, and everybody was safe and happy until we found the problem in 1991. Nothing strange was found in the water from 1984 until 1991.
"Now we're doing excessive testing and designing a system to remove TCE should higher levels be found. We're taking action to protect the public."
TCE was first detected in February 1991, when six parts per billion were found in the county's deepest well, which produces 800 gallons of water a minute.
None of the eight wells showed further traces of TCE until December 1991, when the chemical appeared in a second well in a concentration of less than five parts per billion. TCE was found in the second well again in February 1992, the same time the chemical was again found in the county's deepest well.