Chemicals seeped deep at landfill Toxic solvents found in bedrock at Howard site

February 04, 1993|By Erik Nelson | Erik Nelson,Staff Writer

High levels of toxic chemicals have been discovered in ground water below Howard County's Alpha Ridge Landfill in Marriottsville, deeper than county officials have said the contaminants could penetrate.

Toxic solvents normally used for grease-cutting, dry cleaning or paint removal -- several of them suspected to cause cancer -- were found in bedrock at levels many times higher than federal drinking water standards.

The results could change county officials' thinking about whether nearby residents' drinking water is protected from landfill contaminants, said county public works Director James M. Irvin. At this time, county officials are testing local wells but have not found any that are contaminated.

"There was, historically, a belief that the bedrock could be somewhat of a barrier," he said. How much of a threat the toxins pose is unknown, he said, but the county is stepping up its $100,000 study of ground water movement and contaminant levels below the landfill.

"Hopefully, we'll know something more in the next few months," he said.

The results of two different tests were received by county public works officials in September and November. But Howard's executive and County Council were not told of them until last month.

The results were brought to light by Donald L. Gill, a University of Maryland medical school biochemist who lives in Marriottsville.

Dr. Gill has actively opposed efforts to study a landfill expansion. He alerted County Council members to the test results in a strongly worded letter last week in which he called for one part of the landfill to be closed immediately.

"The current, unlined cell at Alpha Ridge must be closed immediately," he wrote. "All operations at Alpha Ridge should be ceased within 12 months."

"For them to still be dumping on that same site, knowing the levels, is absolutely unbelieveable," Dr. Gill said this week.

John O'Hara, chief of the county environmental services bureau, said that about two weeks ago the county started to use a new lined cell at Alpha Ridge and a leachate collection system. The county must continue to dump trash into the old clay-lined cell to contour its top for proper drainage when it is capped, he said.

County Executive Charles I. Ecker, who met with Dr. Gill about the issue Jan. 21, said he did not know of the results until Dr. Gill told him.

"If those are not a problem now, they certainly are a potential problem," he said of the test results. "If this result is as bad as Dr. Gill says, I should have been given it the day they got the analysis back."

Mr. Irvin said the results were available to the public but were not intended to be presented formally until experts "made sense of what it means and what can be done about the issue."

The toxins were found in samples from a fissure in bedrock between 73 and 76 feet below the surface, said Evelyn E. Tomlin, project manager for the Hydrogeologic Site Characterization Study.

Previous wells at the landfill, drilled 35 to 50 feet down, also showed contaminants beginning in 1990, but those were above the bedrock, she said.

In early August, four shallow test wells were drilled in the landfill's northwest corner, she said, "and in one of those wells we had tetrachloroethene as high as 100 [parts per billion]." The safe level set by the U.S. Environmental Protection Agency for the common dry cleaning solvent is 5 parts per billion.

In late August, a deeper well was drilled, producing two samples with 160 and 200 parts per billion.

The same samples show high levels of methylene chloride, a chemical used for stripping paint. Two samples produced levels of 310 and 430 parts per billion. EPA lists the chemical as a "probable human carcinogen," and considers 5 parts per billion safe.

Also discovered in the deep well samples were several other chemicals in smaller amounts, including Freon, which is not considered dangerous underground but is an indication of leachate, or liquids that have seeped from a landfill.

Dr. Gill said he first obtained results in late October after asking a public works official the purpose of a tall drilling rig on the landfill.

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