Plutonium detected in Snake River Plain Aquifer

By N.S. Nokkentved
Times-News writer

IDAHO FALLS -- Water samples once again have shown the presence of plutonium in the aquifer below a radioactive waste disposal site.

Samples taken independently from two wells near the Radioactive Waste Management Complex at the Idaho National Engineering and Environmental Laboratory in October 2000 turned up minute quantities of plutonium in the Eastern Snake River Plain Aquifer below the site.

No contamination was detected beyond site borders.

Officials can't identify the source, but neither can they rule out the more than 2 million cubic feet of plutonium-contaminated waste dumped haphazardly in pits and trenches -- some of them unlined -- at the INEEL, 580 feet above the aquifer.

"We don't know (the source) at this point," said DeWayne Cecil, research hydrogeologist with the U.S. Geological Survey.

Still, the amounts of plutonium, found independently by state and federal testers, were just at the detection level and well within drinking water standards,

And at those levels, the plutonium presents no health or environmental concerns, said Kathleen Trever of the state's INEEL Oversight Program. The water samples that have turned up plutonium don't show any patterns or trends, she said.

But the state's agricultural economy depends on the aquifer, she said, and "that's why we keep a close eye on it."

And there is no indication of contamination beyond INEEL boundaries or in the Magic Valley, said Flint Hall, hydrogeologist with the oversight program.

In fact, scientists have been finding plutonium and another radioactive element, americium, in the groundwater intermittently since the early 1970s, Cecil said. But there has been no increase in the number of times the radioactive chemicals have been found, or in their concentration.

The contamination could be "cross-contamination" from sampling the surface soil during well construction, contamination from the laboratory, from local bomb testing fallout, or from the burial site or other INEEL facilities, Cecil said.

The federal government dumped plutonium-contaminated and other radioactive waste at the INEEL from 1954 through 1970 -- most of it from the federal nuclear bomb factory at Rocky Flats, Colo.

Another possibility: The results could have been a misinterpretation, Cecil said.

Scientists are working to eliminate possibilities from the list.

The discovery of plutonium in October was not particularly significant by itself, but it was the first time state scientists and federal scientists found confirmed detections in separate wells at the same time.

Officials called a news conference Wednesday to explain that, Trever said.

All drinking water wells across the INEEL are tested regularly, said Kathleen Hain, director of environmental cleanup for the Energy Department at the INEEL.

More samples will be taken in April, she said.

Twin Falls podiatrist Dr. Peter Rickards, a longtime vocal critic of INEEL operations, said the finding raises concerns about the continuing migration of plutonium particles from the buried waste site, which flooded in the past.

And the results call into question cleanup plans for another INEEL facility that include a waste dump that would hold plutonium, Rickards said Wednesday.

State and Environmental Protection Agency officials last week denied Energy Department requests to extend cleanup deadlines for the buried waste at the INEEL's Pit 9 by 88 months.

Times-News environmental reporter N.S. Nokkentved can be reached at 733-0931, Ext. 237, or by e-mail