The Department of Energy is tripling its efforts to clean up chemicals toxic to fish that are seeping into the Columbia River near Hanford's K East Reactor.

DOE and Fluor Hanford have been removing hexavalent chromium from ground water along a stretch of land about a mile long near the Columbia River for a decade. But part of the plume has shifted down river and is not being captured by the treatment system.

The Environmental Protection Agency is concerned not only that the chemical is entering the river, but also that it is spreading toward a separate plume of radioactive strontium. The plumes now are separated by a third to a half mile.

The current system pumps water contaminated with hexavalent chromium out of wells along the Columbia River. It is treated nearby at a rate of 300 gallons per minute before the cleaned water is reinjected into the ground farther from the river.

DOE will use about $3 million of $10 million added by Congress to the Hanford 2008 budget to speed up efforts to expand treatment. Construction began last year on a pump and treat plant planned to double treatment capacity but with enough space to later triple capacity.

The extra money will allow the plant to skip the phased expansion and begin treating contaminated water at a rate of 900 gallons per minute by early 2009. Construction of the plant is expected to be finished by October.

"It shows DOE is really going after the plume," said Larry Gadbois, EPA environmental scientist. The expansion should not only keep more contaminated water from entering the river but also clean up contamination in the aquifer, he said.

The ground water is required to meet drinking water standards of 100 parts per billion and at least half of the plume already meets that standard. A decade of the pump and treat program has significantly reduced the concentration of the chemical in the plume, said Jim Hanson, DOE project lead for ground water near the reactor areas.

But because hexavalent chromium is more toxic to fish and other aquatic organisms, DOE must clean up the water at the river's edge to 10 parts per billion. Now water contaminated at two to 10 times that limit is entering the river.

Salmon typically spawn downriver near the D and H reactor areas, but the chromium near the K East Reactor could be potentially harmful to salmon fry as they spread along the river, Gadbois said. In addition, steelhead spawn in the bottom of the river, but less is known about their use of the river near the K Reactors.

The expanded treatment program would extend its reach to cover the portion of the plume that's spread to the northeast and should prevent the plume from continuing to spread.

EPA is concerned that if the plume reaches the radioactive strontium plume down river at N Reactor, finding a treatment method that works for both chemicals would be difficult, Gadbois said. Strontium tends to cling to the soil, while chromium moves easily with ground water.

The nonradioactive chromium was added as a corrosion inhibitor to water used to cool Hanford reactors that produced plutonium during the Cold War for the nation's nuclear weapons program. At the K East Reactor, the contaminated water then was discharged into a mile-long trench along the Columbia River.