Aberdeen Proving Ground officials said yesterday that samples taken from Aberdeen's drinking water wells were free of the hazardous industrial chemical found recently in the ground water around the wells.
"We didn't find any traces of perchlorate," said proving ground spokesman George Mercer.
All 11 city wells were tested this week. "For the moment, [the results] give us some breathing room," he said. "We don't have to make a quick decision. We obviously have to keep talking to the city and to each other and keep reviewing."
The proving ground will continue to follow a plan devised by the base and city officials Wednesday to conduct more tests to determine the extent of the contamination; monitor well water more closely; create an emergency response if wells must be closed; and to work on a long-term mediation plan.
Mercer said base officials would study current and historical use of the area to try to find the source of the perchlorate, a chemical used in explosives and rocket fuel.
Mercer and Ken Stachiw, the base's environmental cleanup chief, have said training exercises in the area could be a source of the pollution. At Camp Stanton, along the proving ground's northern boundary near the city wells, soldiers use smoke grenades and artillery simulators that contain the chemical.
While the school has not been asked to stop its exercises in the area, Mercer said, "It's something that's being considered in a range of possibilities."
Perchlorate was found in the ground water more than a year ago along the proving ground's northern boundary with Aberdeen, but its proximity to the wells was discovered about a month ago.
In an e-mail dated May 8, the proving ground notified the Environmental Protection Agency that ground water samples in the area contained perchlorate and "that some types of smoke flares and smoke grenades used during training exercises" contained the chemical.
This information was shared with the Maryland Department of the Environment and city of Aberdeen officials; however, at least one community group that monitors environmental issues at the proving ground was not apprised of the situation until several weeks later.
"There can't be a time lag like that, particularly in an instance when it's such a concern to the community," said Cal Baier-Anderson, a University of Maryland toxicologist who advises the APG Superfund Citizens Coalition. "We're all on the same page now. I'm confident they'll keep us updated."
The coalition wants to see all training in the well area suspended. "The Army should relocate all training activities from Camp Stanton to another location, away from the boundary, and more importantly, away from the aquifers that are used by the city and county as a source of drinking water," Baier-Anderson said yesterday.
Also yesterday, Aberdeen City Manager Peter A. Dacey and Public Works Director Randolph C. Robertson briefed City Council members. Dacey said that "APG has elevated this situation to the front burner" and that the city planned to coordinate its monthly well tests with the proving ground so the water would be sampled every two weeks.
Robertson told the council that "perchlorate is showing up in a range of locations around the United States."
One of those places is California, said Kevin Mayer, a scientist and engineer who works in the EPA's Pacific Southwest region office. Research there has found perchlorate can be treated successfully in water, using bacteria or resin, though the process is somewhat complex and can be expensive, he said.
The Defense Department has invested more than $10 million to study perchlorate since the late 1990s. Once technology for analyzing the chemical improved, Mayer said, the EPA found perchlorate is "a much larger problem than we had any idea it would be. There are over 10 million people with perchlorate in their drinking water supplies at 4 parts per billion or higher," he said.
While no national regulatory standard exists for perchlorate, he said the EPA anticipates issuing a health advisory this year that could recommend a safe level for drinking water in the range of 1 part per billion.
"I think it's fair to say it's one of many chemicals that ought not be in people's drinking water because there is some risk to it," Mayer said.