Researchers Probe Island For Radiation

"In the Aleutians, that's pretty good," Unsworth mused. The University of Alberta researcher and a team of five students toiled under those very conditions during a nine-day visit last month to the remote string of US-owned islands, which extend southwest of Alaska.

The group, with the permission of the US Department of Energy and the aid of a grant, travelled to Amchitka Island to measure how much radioactivity is leaking from underground blast sites. The remote island was used for three American underground nuclear tests in the 1960s and 1970s.

Amchitka, which became the heart of anti-nuclear protests and eventually spured the formation of Greenpeace, was the home of Project Cannikin, the largest of the three tests. The 1971 blast from the five-megaton warhead test measured 7.1 on the Richter Scale and left a caved-in crater almost two kilometres wide and 18 metres deep. The crater later became the largest lake on the island.

Though the US government cleaned up the surface in 2001, "there's not been a systematic examination" of the underground sites since the 1970s, said Unsworth, a geophysics professor in the U of A’s Faculty of Science.

He and his team--U of A students Wolfgang Soyer, Volkan Tuncer and William Shulba and two students from the universities of Alaska and British Columbia--were funded by the Consortium for Risk Evaluation with Stakeholder Participation (CRESP). The organization was set up by the US government to remediate all Cold War-era nuclear weapons sites.

Visiting the abandoned island was a poignant experience, Unsworth said. "It was the frontier in the Cold War…the end of the line against the Soviets. It was such a needless test. We saw such a pristine wilderness area, and you've got to ask yourself if it was necessary to do that. It was a little bit haunting."

Bundled against the elements and wearing radiation badges (which showed safe readings for surface radiation), they traversed the island, which is 48 kilometres long and almost five km wide. They measured radiowaves from the atmosphere that penetrate the Earth, revealing fractures around the test sites that in turn, lead to clues about the condition of the groundwater.

Especially vital is information about contamination of the island's tables of saltwater and fresh water. "The contaminated groundwater will, within 50 to 100 years, start oozing into the Bering Sea," Unsworth said. While little can be done to prevent the leakage, nearby fishermen and Aleut communities can be warned when it does happen, he added.

"If you know this stuff is coming out, you can do more enhanced monitoring and keep people away from contaminated areas." The leakage will flow out more quickly if it is in the fresh water, as opposed to the more stagnant layer of saltwater, Unsworth said.

The team also took some global positioning measurements to gather updated information on how much the island is changing shape in response to plate tectonics, he added. Previous data has shown that the island is stretching lengthways, which could open up fractures.

While the team must first share its findings with CRESP, the information will also be published in scientific journals, Unsworth said.

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Related links

Dr. Martyn Unsworth's U of A webpage: http://www-geo.phys.ualberta.ca/~unsworth/

The U of A Department of Physics website: http://www.phys.ualberta.ca/

CRESP website: http://www.cresp.org/