By Paul Duggan and David A. Farenthold
Washington Post Staff Writers
Friday, May 16, 2008

District officials yesterday sought to ease any urgent worries about the high levels of arsenic found in soil at Fort Reno Park, saying that the contamination is not a serious public health threat and that the problem might not be widespread at the 33-acre field in Northwest Washington.

Speaking to reporters gathered at the federal park, which has been closed to the public since Wednesday, Mayor Adrian M. Fenty (D) and a number of environmental and health officials said that the contamination might be confined to a few hot spots at Fort Reno and that arsenic in the soil might be at safe levels elsewhere in the park.

"There has, within the past two years, been testing at both Fort Reno" and nearby Woodrow Wilson Senior High School, Fenty said. He said those tests, by the Army Corps of Engineers, did not find excessive levels of arsenic, meaning that D.C. officials had "no reason to believe the soil was hazardous."

But recently completed tests by the U.S. Geological Survey on a half-dozen soil samples from the park showed arsenic levels of as much as 1,100 parts per million -- about 25 times the safe limit of 43 parts per million set by the U.S. Environmental Protection Agency.

What caused the contamination is unclear, officials said. Fort Reno is run by the National Park Service.

Federal and District environmental specialists began more extensive soil testing yesterday at the park, a popular site for sports and concerts in the Tenleytown neighborhood. "Hopefully, we'll be able to come back to the community and the media [with results] within the next 24 to 48 hours," Fenty said.

Officials have cordoned off a dirt area near the football field at Wilson High for testing. Fenty said tests had not found excessive levels of arsenic in the water supply in the area or on the grounds of nearby Alice Deal Junior High School or the city's Turtle Park.

The federal Agency for Toxic Substances and Disease Registry says excessive exposure to arsenic can cause nausea and vomiting, abnormal heart rhythm, damage to blood vessels and -- if very high doses are ingested -- death.

But experts on arsenic in soil say that in places where arsenic is contained in dirt covered by grass, it probably does not pose an immediate threat. They said it is unlikely that people in such an area would breathe in enough arsenic in airborne dust to threaten their health.

Joining Fenty yesterday were George S. Hawkins, director of the D.C. Department of the Environment; D.C. Council member Mary M. Cheh (D-Ward 3), who represents the area; Carlos Cano, a senior doctor with the city's Health Department; and other officials.

"We don't currently know why the samples that were done just recently showed these high numbers," Hawkins said. "That's why we're here. We will go out, we will do soil samples, they will be sent to a lab, and we will get very detailed and accurate results."

Tests done in recent years, he said, "did not find anything beyond what we call background levels. Because arsenic is naturally occurring, it was at low levels, and low levels do not present a health risk."

But, Hawkins said, the site "is big enough that those samples wouldn't necessarily have covered" the places where excessive levels were found. "There absolutely could be hot spots with arsenic," he said. "There could be particular places where there are high levels and others not."

If experts determine that contaminated soil at the park should be removed, Cheh said, "we will take [action] immediately."

Cano said people who have used the park should not worry about health effects because the contaminated soil could be harmful only if swallowed.

"There's no recommendation for [medical] testing to be done on residents at this point," he said. "This would not be considered an acute toxic event, so there's no urgency to have anybody tested."

In a telephone interview, environmental scientist Joseph Graziano, who teaches at Columbia University, agreed with officials who played down the public health risk.

"One has to swallow the soil" for it to be hazardous, Graziano said. Although small children playing in the dirt might swallow some of the dust clinging to their hands, he said, a child would have to be exposed repeatedly to be in danger.

He said studies of arsenic-contaminated groundwater in Bangladesh found that many people did not show symptoms of illness until they had been exposed for 10 years or more.

"One-time ingestion of a little bit of dust on the hand . . . would not be a concern," Graziano said.