Study: Hanford Chemical Seeping into Columbia
by Jonathan Brinckman
A toxic chemical seeping into the Columbia River from closed nuclear reactors at the Hanford Nuclear Reservation poses no danger to salmon, according to preliminary results of a study released this week.
The findings are important because the Hanford Reach, a 51-mile stretch of the Columbia running past and through the nuclear reservation, is the spawning grounds for 80 percent of the river basin's remaining wild fall chinook. Those fish, whose numbers have exceeded 150,000 in recent years, are the mainstay of the Columbia's sport and tribal fisheries.
The federally funded study found that levels of hexavalent chromium up to 266 parts per billion do not kill salmon eggs or young salmon or cause deformities. Although hexavalent chromium levels as high as 400 parts per billion have been found in a spring seeping into the river, chromium has never been found at levels above 130 parts per billion in the river gravel where salmon spawn.
Although the drinking water standard for chromium is 100 parts per billion and the standard for protecting aquatic organisms is even more stringent, at 11 parts per billion, the study found that the higher levels of chromium did not harm developing salmon. Scientists think that's because chromium affects gills; salmon eggs and newly hatched salmon do not have gills.
Hexavalent chromium is a toxic chemical added to water used to cool reactors. Huge volumes of cooling water were used, and the spent coolant was discharged into the river or into the ground, contaminating the ground water.
Hexavalent chromium is one of the two chemicals or radioactive elements leaking into the Columbia from the site that Hanford managers are most worried about.
The other is strontium-90, a radioactive element that has leaked into cooling water used in nuclear reactors. Hanford officials said that neither has been found at levels that would threaten fish.
But a scientist who works for a Seattle-based advocacy group said thorium, another radioactive element from Hanford, is present in the riverbed at levels high enough to threaten fish.
Norm Buske, a physicist consulting for the group Government Accountability Project, said Wednesday that he has found elements from the decay of radioactive thorium at dangerously high levels for fish. Buske, a longtime Hanford watchdog, made headlines in 1990 when he mailed strontium-contaminated mulberry jam made from mulberries picked at Hanford to the U.S. energy secretary and the governor of Washington.
Although neither strontium nor chromium poses an immediate threat, Buske said, thorium is worrisome. "We don't see anything in the springs that is a public health problem or environmental hazard at this time," he said. "It looks like the biggie is thorium."
However, Michael Thompson, acting manager of the U.S. Department of Energy's groundwater cleanup project at Hanford, said Buske is wrong about thorium. "We haven't found thorium in the environment at levels of concern," Thompson said. "He's brought this issue up before, and it doesn't hold water."
Hanford was established in 1943 to produce plutonium for the first nuclear weapons used in World War II. It is the most contaminated of the Energy Department's nuclear weapons complexes, with 60 percent of the nation's high-level nuclear waste and 80 percent of its spent fuel rods for nuclear reactors.
Waste disposal practices through the 1970s were poor. Water contaminated with toxic chemicals or radioactive elements, for example, was usually discharged into trenches called "cribs" and allowed to seep into the ground untreated.
Now, the ground water beneath 100 square miles of the 560-square-mile Hanford site is contaminated by toxic chemicals or radioactive elements at levels higher than permitted in drinking water.
The cleanup program at Hanford costs about $1 billion a year. Of that, $7 million is being spent to pump and treat contaminated ground water. The Energy Department monitors contamination seeping into the Columbia.
"We are finding some localized areas of concerns where we have treatment systems in place," Thompson said. "The focus of my energy today is what has not reached the ground water yet. We have to get our hands around that."
Two radioactive elements are detected in the river at higher levels downstream from the Hanford site than upstream, but Hanford managers said neither poses a risk to human health or to wildlife.
Tritium is found in river water at 75 picocuries per liter to 100 picocuries per liter at Richland, below Hanford. That compares with 25 picocuries per liter to 40 picocuries per liter at Priest Rapids Dam, above Hanford. Tritium is permitted in drinking water at levels up to 20,000 picocuries per liter. A picocurie is one-trillionth of a curie, the unit used in measuring radioactivity.
Iodine-129 is also found in river water at slightly higher concentrations at Richland compared to levels at Priest Rapids Dam. But concentrations are extremely low, far below the water quality standard.
Further information about these contaminants in Hanford ground water and the Columbia River can be found at two Web sites: http://hanford.pnl.gov/groundwater and http://hanford.pnl.gov/envreport.
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