Experts told Woodbine residents last night that contaminants from the Carrs Mill Landfill don't appear to be migrating across a stream to neighboring homes, but that they can't be certain.
James W. Mercer, president and principal hydrogeologist for Virginia-based GeoTrans Inc., told about 15 residents at Glenwood Middle School that the contaminants are draining into the Cattail Creek.
His company conducted a $139,000 study of contamination at the landfill and how to clean it up.
Responding to questions about possible migration of the chemicals through ground water under the creek, he said his conclusion is supported by water samples collected from wells on the eastern, or landfill side of the creek, and from contaminants found in the creek itself.
But the company has not yet been able to drill monitoring wells on the other side of the creek where the houses are. The reason, said County Executive Charles I. Ecker, is that the property owner directly across Carrs Mill Road from the drum site won't grant an easement to the county to drill monitoring wells.
Susan M. Miller said that she owns the property, and that she and the county have not reached an agreement over terms of the easement.
"I'll volunteer my home," said Gail Tarrico, who lives to the north of Ms. Miller.
County Public Works Director James M. Irvin said the county would consider her offer.
Studies of the Carrs Mill facility and the New Cut Road Landfill in Ellicott City -- both closed -- and the operating Alpha Ridge Landfill in Marriottsville, examined the extent of pollution, assessed its health threat and recommended cleanup methods.
County officials and experts have told residents near the Alpha Ridge Landfill that the Little Patuxent River would be a barrier to contamination, but contamination found in a monitoring well across from the landfill appeared to disprove that theory.
While most residential wells near the Carrs Mill and Alpha Ridge landfills have not shown any contamination in periodic tests, one home across the Cattail Creek showed a trace amount of a solvent in one sample.
Several of the New Cut Road facility's neighbors have had contaminated residential wells, and the county is in the process of hooking up public water to those homes.
At the 20-acre Carrs Mill Landfill, hazardous waste cleanup crews in head-to-foot protective gear have removed drums since October.
With no more drums in the current excavation, cleanup crews are using sophisticated metal detectors to see if there are other pockets of buried drums.
Mr. Irvin, the public works director, told residents that the county is contacting companies believed to be responsible for some of the dumped chemicals.
He would not name the companies pending settlement of the county's damage claims, but said it is possible that recovering money to help pay for the $1.1 million cleanup of the drums could take as long as 10 years.
To help clean cancer-causing solvents from the drums and other contaminants, county officials say they expect to adopt the consultants' recommendation to pump out ground water and aerate it, or mix it with air bubbles.
The treated water would then be pumped into a nearby stream such as Cattail Creek.
The cost of the collection and treatment system is estimated to be $680,000.
The report also recommends capping the landfill with plastic to keep rainwater from percolating through it, and installing a system to vent methane gas -- a byproduct of rotting garbage.
The recommendations, including capping, venting and operating costs, are expected to cost between $5.3 million and $6.6 million.