Groundwater Toxin Found at Additional D.C. Sites
Saturday, February 18, 2006
More testing for groundwater problems in Northwest Washington neighborhoods where the U.S. Army researched chemical weapons during World War I has found new locations of perchlorate contamination, at some of the highest levels detected to date, according to officials.
Undetermined is whether the contamination could end up in the Dalecarlia Reservoir or the Washington Aqueduct, both of which supply drinking water to more than 1 million people in the metropolitan area.
The three federal and city agencies involved in a multimillion-dollar cleanup of the Spring Valley community released data this week that showed elevated perchlorate concentrations in a monitoring well near the reservoir and in two other wells adjacent to where ordnance and laboratory glassware were dumped during the heyday of the Army's American University Experiment Station.
The latest findings were from sampling in December. Perchlorate, a compound that was used nine decades ago in tests with mustard agent and screening smokes, can disrupt thyroid function and can contribute to developmental delays and infertility.
Given that two of the wells are just west of major disposal pits, the December findings were not surprising. They showed levels of 60 and 70 parts per billion, which exceed the previous high of 58 parts per billion detected in 2003 on the grounds of Sibley Memorial Hospital and are more than double a federal recommendation for perchlorate cleanup.
Much more unexpected, however, was the 48 parts per billion reading from the third well, about 1,000 feet south of Dalecarlia at Loughboro Road and MacArthur Boulevard.
"It's not real apparent where that perchlorate is coming from," said Gary Schilling of the U.S. Army Corps of Engineers, which is leading the project.
Twenty-nine wells have been installed throughout Spring Valley in the past nine months, aimed at answering that and other questions. Chief among the questions is whether the groundwater could breach the reservoir. Schilling considers that highly unlikely but acknowledged, "We're concerned with finding out where this stuff is flowing."
No Spring Valley residents use groundwater for drinking, cooking or bathing. Officials continue to vouch for the safety of the drinking water processed from the reservoir by the Washington Aqueduct and supplied to the District, Arlington County and Falls Church.
"It is not a drinking water concern," District Health Director Gregg A. Pane reiterated yesterday. Testing of water in the reservoir and of the aqueduct's finished product has only periodically shown the presence of perchlorate, at amounts about 2 parts per billion or less, officials said. But even those traces have raised questions given the ever-closer proximity of perchlorate in the groundwater, especially at the more elevated levels.
While praising the investigation for taking "all the right actions," Pane said anything that could put the reservoir at risk is worrisome.
Virginia Commonwealth University scientist Peter deFur, the consultant to a residents advisory board on the cleanup, agreed that the reservoir's potential vulnerability is "the controlling question in terms of an immediate threat to public health." How and where further sampling will be conducted and how the investigation will be broadened should be determined during the next month.
The December results from the six newest wells also showed low levels of arsenic and an unconfirmed finding of HMX, or high melting explosive. But recently validated analyses from samplings of more than a dozen wells revealed no detectable traces of more than 160 chemicals and elements used at the experiment station during World War I, groundwater project manager Ed Hughes said.