After discovering traces of several toxic chemicals exceeding the maximum acceptable levels in ground water at a former landfill at Fort Meade - including benzene and PCBs - officials working on the Army base's cleanup are making the landfill their top priority.
The base, which was placed on the federal Environmental Protection Agency's Superfund list of hazardous-materials sites slated for cleanup, has identified several other areas it needs to clean and study. But during the next six to eight months, it will be shifting resources to the former post landfill, said Fort Meade's environmental engineer Jim Gebhardt.
"We're at the very early stages, but it's going to happen real fast," Gebhardt said.
State and federal officials monitoring the cleanup made the decision to shift focus last week at their monthly session after reviewing data from the sampling of ground water, in December. Monitoring wells are tested every six months, and, for about two years, the levels of certain chemicals have been increasing, officials said.
Among the most worrisome chemicals are PCBs, or polychlorinated biphenyls, a known carcinogen in animals and suspected of causing cancer in humans. The well testing found 1.610 parts per billion of PCBs in one of the former landfill's southern wells, more than three times the maximum acceptable level of 0.5 parts per billion.
It's the first time the compound has surfaced there, leading the engineering firm conducting the testing, CH2M Hill, to suspect its presence is an anomaly.
But to Gebhardt, "it's definitely a big concern," he said, particularly because PCBs are most often found in electrical equipment and are not known to show up in ground water.
Another well just south of there posted readings of arsenic at 51.9 parts per billion, exceeding the 50 parts per billion limit that the government is considering lowering. Benzene, a known carcinogen made from oil and coal, also showed up in the well at 7.4 parts per billion, exceeding the 5 parts per billion allowed.
Beryllium, a chemical used in electronics manufacturing and nuclear reactors, slightly exceeded its allowable threshold. In high doses, beryllium can cause lung failure.
In addition, the monitoring report showed several other chemicals had increased slightly, even though they hadn't exceeded their acceptable thresholds.
"At this rate, we probably have two years on some of these before we reach the maximum contaminant level, but we better do something now," Gebhardt said.
The findings don't affect county drinking water, which comes from the aquifer's lowest layer, the Patuxent Aquifer. The increases in contaminants were found in the Upper and Lower Patapsco aquifers, according to CH2M Hill report. Each is sealed off with a layer of clay and gravel, which prevents solvents from seeping into the next layer.
The Lower Patapsco serves a few private wells in Odenton, but so far no contamination has surfaced, said Curtis DeTore, a geologist with the Superfund division of the Maryland Department of the Environment.
The latest findings follow news last fall that traces of carbon tetrachloride, a rarely used solvent once commonly used in dry cleaning, turned up in a well north of the landfill. Officials consider the landfill an unlikely culprit for the carbon tetrachloride because the well is upstream from the landfill.
While officials believe the landfill could be causing the higher readings in the southern wells, they are also looking into sources off the base: the monitoring wells are next to an Amtrak rail yard, a possible contributor.
To determine the source, officials will have to install more wells, each costing about $30,000 to install.