Radioactive waste from leaking underground tanks at the Hanford nuclear reservation in southeastern Washington State has reached ground water, according to studies reported in The Oregonian.
The Department of Energy planned to release two reports Nov. 25 by the agency's Pacific Northwest National Laboratory that conclude waste from at least five of Hanford's two-dozen tank groups has reached water below the tanks.
The tanks contain about 54 million gallons of waste, byproducts of four decades of plutonium production at the sprawling nuclear reservation on the Columbia River.
Until recently, Hanford officials believed contamination from the nuclear reservation's 177 underground waste tanks - 67 of which are suspected to be leaking - was soaked up by the area's dry soil, suspending pollution far above the aquifer.
But the new studies confirm waste from the tanks has reached the water about 230 feet below the tanks.
Jackson Kinzer, a senior Energy Department official for tank cleanup, says the new reports would make little difference in how Hanford approaches the groundwater problem.
"This just validates the fact that tanks are contributing" to the pollution, he said.
A $29.5 billion project is under way to clean up the tanks by sluicing them with water to remove radioactive solids.
Hanford officials are unsure whether the contamination that has reached the ground water might eventually seep into the Columbia River, which flows through the 560-square-mile reservation.
The groundwater beneath the tanks already contains contaminants from more than 300 billion gallons of waste water that was pumped into the ground at Hanford from 1945 until recently. K. Mike Thompson, Hanford's ground-water manager, says the rate of flow of the aquifer has slowed in recent years because water-dumping has been stopped.