Tests find more MTBE in well water

Gasoline additive discovered near Baltimore County homes


Mandatory testing of groundwater at Maryland service stations has led to the discovery of a significant level of a gasoline additive in residential wells in northern Baltimore County.

Tests showed that two wells at homes near a gasoline station had concentrations of methyltertiary butyl ether - commonly known as MTBE - at dozens of times the level deemed safe by the state. Three other wells had much smaller traces of the chemical.

The residential wells were tested after the discovery of contaminated groundwater at a Citgo station operated by Wally's Country Store in Parkton.

The station performed the tests under emergency regulations imposed by the state in January that required all service stations near homes that rely on well water to test their groundwater.

"It validates what we've done with the emergency regulations," said Herbert M. Meade, chief of the Maryland Department of the Environment's oil control program. Meade said the department plans to push for the regulations, set to expire in January, to become permanent.

Those regulations were instituted after the chemical, which has been linked to cancer in laboratory animals, contaminated more than 225 residential wells near an Exxon station in the Fallston area of Harford County.

Property owners in Fallston were harshly critical of the way the Department of the Environment handled contamination there.

John Niland, who runs a business installing and replacing home heating oil tanks, said Maryland should have instituted mandatory testing for the chemical eight years ago, when California was having problems with MTBE.

"Anybody who's been really involved in this over the years knew that MTBE was a big problem. It was just that state and county governments would not let this information surface," Niland said. "Now, as a result of the new regulations, the reality of the MTBE releases are starting to appear."

Meade said that until recently, the state lacked studies to justify the regulations, which some service stations owners said would be too expensive and would hurt their businesses.

"We simply didn't have the punch that we needed to force the issue," Meade said.

The chemical is added to gasoline to make it burn more cleanly. Its toxicity to humans at low levels has never been determined.

The Maryland Department of the Environment requires remedial action when well water shows MTBE concentrations at 20 parts per billion, the level at which the water tastes and smells like gasoline.

State environmental officials say the latest contamination was discovered after Carroll Independent Fuel, which serves the Citgo station in Parkton, tested the groundwater under the station at Middletown and Rayville roads, at the top of a hill overlooking rolling pastures and frame houses.

Tests showed that water from a monitoring well at the station had an MTBE concentration of 17,000 parts per billion - 850 times the level deemed safe by the state. The station is in the 1600 block of Rayville Road.

Water serving Wally's Country Store was not found to be contaminated.

After notifying the state of the contamination, the station tested the well water of 27 nearby houses. Baltimore County's Department of Environmental Protection and Resource Management sent letters to property owners within a half-mile radius of the station notifying them of the contamination.

The well water from the house nearest the station contained a concentration of 2,670 parts per billion.

"It's pretty amazing that this resident hadn't noticed this level from taste and odor, taking a shower or tasting this water," Meade said. The property owner could not be reached for comment.

Well water from the house next door contained an MTBE concentration of 850 parts per billion.

Carroll Independent Fuel initially provided bottled water to those residents and installed carbon filtration systems in their homes.

State officials believe the contamination is due to vapor leaking from the station's underground storage tanks. The company has replaced several storage tanks and is performing more groundwater tests to try to isolate the problem, Meade said.

Emergency guidelines imposed by the state this year require groundwater testing by all service stations near houses that use residential wells. The regulations require that service stations install three monitoring wells and test the water for MTBE. The rules also require double-walled tanks and pipes when new fuel tanks are installed.

Meade said almost every station that has installed the monitoring wells has found traces of MTBE in the water beneath its facilities, including two sites in Carroll County in October.

But he said the two houses in Parkton have the only residential wells to show high enough concentrations of MTBE to trigger state intervention.


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