Mount Airy's water supply contains a high -- but no dangerous -- level of a solvent used in dry cleaning, pesticides and manufacturing, officials said yesterday.
The chemical -- tetrachloroethylene -- was discovered in a test performed Monday during an investigation to find out what is causing health problems at Mount Airy Elementary School, Town Council President R. Delaine Hobbs said.
Carroll school officials will begin providing bottled water to the school today , even though it is probably an "overreaction," said Vernon Smith, director of school support services.
The bottled water may help allay concern among parents and keep from clouding the issue about whether something in the building's air is making first- and second-graders ill, he said.
Mount Airy's level of tetrachloroethylene is 4.9 parts per billion, Mr. Hobbs said. The level acceptable to the U.S. Environmental Protection Agency is five parts per billion.
Mr. Hobbs, who also is the town water commissioner, said the level found in the town water is not harmful.
"It's high, but it's not past the limits. We are well within our limitation. There are no harmful effects," he said.
Charles L. Zeleski, assistant director of environmental health at the Carroll County Health Department, said a person would have to drink two liters of tetrachloroethylene-contaminated water per day for 70 years before experiencing carcinogenic effects.
Mr. Smith said he consulted Tuesday with state and local health officials, who said the chemical was not likely to be the cause of the symptoms that sick students reported. He said any effects from the chemical at the level found in Mount Airy would not cause acute symptoms.
Bottled water will not be provided at Mount Airy Middle School.
Officials suspect that a high bacteria count in one room at the elementary school may be causing health problems. Health officials still are not sure whether the bacteria are the cause of the eye, throat and sinus irritation some students have reported.
Mr. Hobbs said he does not know how the solvent got into the water system.
Another test will be performed today to try to isolate which area watershed the chemical is coming from, he said. Results are expected to be available in 10 days.
The town hired Fredericktowne Labs of Myersville to do the tests, Mr. Hobbs said.
The federal Clean Water Act requires testing of public water systems for tetrachloroethylene and about 60 other volatile organic chemicals, Mr. Zeleski said.
Mr. Hobbs said no traces of any of the other volatile organic chemicals were found in Monday's test.
The Maryland Department of the Environment tested the town's water supply in 1989 and 1992 for these chemicals and found no trace of tetrachloroethylene or any of the other chemicals.
Mr. Hobbs said the town will test monthly for these chemicals.
"We don't take chances, and we don't do anything to cover up," he said.