Aberdeen well shut after chemical test

Drinking water found to contain perchlorate

October 03, 2002|By Lane Harvey Brown | Lane Harvey Brown,SUN STAFF

Aberdeen's drinking water has tested positive for the first time for a chemical linked to thyroid cancer that Aberdeen Proving Ground officials acknowledge likely came from military testing near the town's wells, further raising concerns about safety of the water and the Army's response to the contamination.

The city shut down one well Tuesday afternoon and cut production of two others in half.

But, city and proving ground officials stressed yesterday, the test results are mixed - a test done Sept. 24 that came back Tuesday showed perchlorate at the state's recommended maximum level. But two tests yesterday by the city and the post were described as "non-detects," meaning the levels were not present or were below the reporting limit of 1 part per billion.

"The test results we got back were non-detects, and what this means is there very well could be and may be some perchlorate in there below reliable, detectable levels," said post spokesman George Mercer. "Our understanding of a reliable, detectable level is 1 part per billion."

Perchlorate is a key component in explosives and is known to disrupt thyroid functions.

In August, the Maryland Department of the Environment recommended an advisory level for perchlorate in Aberdeen's drinking water of 1 part per billion. Last night, department spokesman Richard McIntire said the city and the proving ground are "taking appropriate steps to ensure that this material does not reach the public."

Randolph Robertson, Aberdeen's director of public works, said town officials are concerned, but that drinking water is not unsafe. "At this level, the water is still safe to drink," he said. "It's not dangerous."

The city's 11 production wells sit along the post boundary. Water is pumped from these wells and treated before going to homes as drinking water. He said the city had shut down one well, No. 9, and decreased the production of two other wells, Nos. 8 and 10, to 50 percent as a precaution and would be taking more water from the county's water system.

Well No. 9 had been was shut down in June after it tested positive for perchlorate, but was reopened recently, Robertson said, after tests showed a drop in the perchlorate level.

Aberdeen tapped the wells after residents complained about the taste and smell of water that the town had been buying from Harford County.

Proving ground environmental officials have said that shutting down the wells could cause the contamination to travel toward other uncontaminated wells that are still pumping. But Saeid Kasrai, a Department of the Environment water supply program administrator, said last night that shutting down the wells was a reasonable response.

"Precaution is much better than making the assumption that it will move in that direction," he said.

Cal Baier-Anderson, a University of Maryland toxicologist and technical adviser to the Aberdeen Proving Ground Superfund Citizens Coalition, disputed whether the results were truly "non-detects." She said that, based on information she has received from the Environmental Protection Agency, the minimum detection level of the tests is 0.2 parts per billion.

"There is a difference between the minimum detection limit and the minimum reporting limit," Baier-Anderson said. "Just because the measured value is below the method reporting limit does not mean that it is a non-detect."

Perchlorate was discovered within 300 feet of the city wells in the spring, near a training area in the northern corner of the proving ground where smoke bombs and other weapons that obscure vision are used in exercises. The Department of Defense has said it will not authorize and fund cleanups until the EPA issues a national standard on perchlorate.

Although toxicological evidence shows the chemical can cause thyroid cancer, experts disagree about what level of exposure poses a risk. No national standard exists for perchlorate in drinking water, though the EPA is expected to issue a regulatory limit in the near future.

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