Nancy Cook Lauer / West-Hawaii Today – 2008-01-20 22:44:54
Military: No Imminent Threat from Depleted Uranium Fast-track Plan Set for Cleanup of Pohakuloa
Nancy Cook Lauer / West-Hawaii Today
HONOLULU (January 18, 2008) — While the state Health Department on Thursday released data showing relatively low radiation readings across the Big Island, military officials told lawmakers they had fast-tracked a plan to identify and clean up depleted uranium at the Pohakuloa Training Area.
Technicians are scheduled to be on the ground doing preliminary work at PTA the last week of January, Col. Howard Killian, deputy director, U.S. Army Installation Command-Pacific Region, told a joint briefing of the House and Senate committees on Public Safety and Military Affairs.
Killian said the military has spent more than $2.2 million, invested more than 5,000 man-hours and sent more than 16,000 air, plant and soil samples to mainland labs for analysis since depleted uranium was first discovered at Schofield Barracks on Oahu in 2005. The military didn’t find out about PTA until last summer, so work there is in its early stages.
“There is no imminent or immediate threat to human health from the (depleted uranium) present on Hawaii’s ranges,” Killian said.
After the initial scoping of PTA in August, the Army has created a survey based on old maps of the area and determined where the likely target areas were. Some soil samples were taken then, but more soil samples and groundwater samples will be taken as the survey proceeds, an Army spokeswoman said.
Laurence Lau, deputy director of the Environmental Health Administration, said the samples are being split so that two independent labs will evaluate each one to provide cross-checking and for additional reassurances for the public.
The depleted uranium was used in spotting rounds in Davy Crockett weapons systems in the 1960s, and the spotting rounds are most likely to be clustered in an area close to Breadlake Trail.
Lawmakers from the Big Island, however, want to know why the Hawaii National Guard continues to fly B2 bombing missions at PTA since the military’s analysis hasn’t been completed.
“What bothers me is that you’re doing all of this work, and we still continue to do the bombing,” said Lorraine Inouye, D-Hamakua, South Hilo, who is heading the Senate committee.
Inouye worried that the planes and bombs would kick up dust that could be contaminated. But Killian said the depleted uranium that’s being found is in large metal pieces, not something that goes airborne.
“Is there any place else in the state you could practice your air bombing?” asked Rep. Cindy Evans, D-Kona, who heads the House committee.
Unfortunately not, said Gen. Robert Lee, adding that PTA is large enough to avoid the sites most likely to have traces of the weapons containing depleted uranium. He said the bombers are practicing “pinpoint precision” such as they need to do when enemies shield themselves with innocent civilians. The point is to avoid collateral damage, Lee said.
“They’re flying over the training areas versus going into the impact areas,” Lee said.
Some in the audience left the 11/2-hour hearing dissatisfied with the answers they heard. Lorrin Pang, a medical doctor, army retiree who specialized in preventative medicine and current employee of the state Department of Health, emphasized he was speaking as a private citizen. He’s attended several meetings and isn’t accepting the military line, he said.
Pang pointed out that the military never disclosed the presence of depleted uranium until it came out in a lawsuit. He said the Army is concentrating only on the metallic form of depleted uranium instead of doing a survey to determine what else might have been used at the training areas.
“Because there are so many unknowns, we must take the most cautious approach,” Pang said.
Killian acknowledged that the military had been less than accurate when it said no depleted uranium had been used. But he said the Army didn’t know.
“The Army did not intend to mislead the public,” Killian said.
• Army has created a brochure and also has an e-mail address, firstname.lastname@example.org, for more information and to air citizen concerns.
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‘Pac-Man’ Molecule Chews Up Uranium Contamination
Paul Marks / New Scientist
(January 17, 2008) — A molecule that can bite a uranium-containing ion between its “jaws”, not unlike the munching blob in the arcade game Pac-Man, could one day lead to a way to clean up groundwater contaminated with the toxic metal.
Uranium leaches into groundwater from natural deposits of its ore, depleted uranium munitions, nuclear facilities and the detritus of uranium mining. It occurs most commonly in the form of the water-soluble uranyl ion, (UO2)2+, in which the uranium atom is linked to two oxygen atoms by double bonds.
Allowing uranyl to react with other substances might change it into a different, insoluble ion, which can be filtered out. But uranium binds very strongly to oxygen – the bonds it forms are 25 per cent stronger than typical double bonds – making the uranyl ion very stable. Combined with its solubility, this makes dissolved uranium virtually impossible to remove. “It’s a very problematic, persistent groundwater contaminant,” says Polly Arnold, a chemist at the University of Edinburgh in the UK.
Enter Pac-Man. Arnold’s colleague Jason Love had been working on improving catalysts for fuel cells using a large organic molecule known as a macrocycle, that can fold in half to form a structure like a pair of jaws. Love was using the gap between the jaws to capture a pair of cobalt ions, but Arnold realised that it was just the right size and shape to clamp onto a uranyl ion.
When she added the macrocycle molecule to uranyl ions dissolved in an organic solvent, she found that it did indeed capture them in its jaws, leaving one oxygen atom protruding (Nature, DOI: 10.1038/nature06467). What’s more, a silicon-containing compound present in the mixture was able to bind to the protruding oxygen atom, a sign that the uranyl’s stubborn bonds with oxygen had been weakened.
Because the macrocycle is destroyed by water, it cannot be used to remove uranium from contaminated water. But Arnold’s team believe their demonstration that the uranyl ion’s bonds can be loosened is a first step towards finding substances that can transform dissolved uranyl into an insoluble compound. “No one has been able to do this before,” says Arnold. “We might now be able to develop and suggest new pathways for uranium removal from solution.”
Robin Taylor, a chemist with Nexia Solutions, the research arm of British Nuclear Fuels in Sellafield in the UK, says the findings will help develop better processes for uranium sequestration and boost confidence in dealing with nuclear materials and waste.
The Edinburgh team will also investigate how some bacteria and iron-rich minerals reduce uranium concentrations naturally in contaminated water, and whether the macrocycle is able to loosen bonds in ions containing plutonium.
From issue 2639 of New Scientist magazine, 17 January 2008, page 24
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