Tests detect iodine-131 in samples taken in Lower Mainland
By Tracy Sherlock, Vancouver Sun



Radiation from the Japanese nuclear reactor damaged in the March 11 earthquake and tsunami has been detected in B.C. seaweed and rainwater samples, researchers say.

Tests found iodine-131 in samples taken in the Lower Mainland on March 19, 20 and 25, Simon Fraser University said in a news release Monday.

SFU nuclear scientist Kris Starosta is confident the Fukushima Daiichi nuclear power plant is responsible for the recent discovery, but he said there is no immediate danger to the public.

"As of now, the levels we're seeing are not harmful to humans. We're basing this on Japanese studies following the Chernobyl incident in 1986 where levels of iodine-131 were four times higher than what we've detected in our rainwater so far," Starosta said. "Studies of nuclear incidents and exposures are used to define radiation levels at which the increase in cancer risk is statistically significant. When compared to the information we have today, we have not reached levels of elevated risk."

The rainwater was collected at SFU's Burnaby campus and in downtown Vancouver, while seaweed samples were collected in North Vancouver near the SeaBus terminal.

"The only possible source of iodine-131 in the atmosphere is a release from a nuclear fission," Starosta said. "Iodine-131 has a half-life of eight days, thus we conclude the only possible release which could happen is from the Fukushima incident."

The radiation found in B.C. was carried by the jet stream, and is now falling over the West Coast with rain, which is mixing with sea water and accumulating in seaweed, SFU said in the news release.

Japanese officials are still struggling to stabilize the situation at the six-reactor Fukushima Daiichi complex. The situation remains "very serious," the International Atomic Energy Agency said on Monday.

The plant's operator said radiation above 1,000 millisieverts per hour was found on Monday in the water in the underground tunnels near the plant, Reuters news agency reported.

When asked what effect the radiation released in Japan might have on fish, Starosta said he could only speculate.

"One thousand millisieverts per hour is a lot, but this has been only detected in the service tunnel under the plant. The amount fish can be exposed to will be different. The signatures may be very weak if the leak is small and the contamination is diluted."

Radioactive water leaking from a reactor at Japan's damaged nuclear plants isn't likely to harm B.C. salmon because they don't travel as far as the coast of Japan, said Nancy Davis, deputy director of the North Pacific Anadromous Fish Commission.

"They tend to go to the Gulf of Alaska, the Bering Sea, or maybe as far as the central North Pacific, but they are not maturing off Japan and swimming all the way back here," Davis said. "Immature and maturing salmon are in the deep ocean, they're not on the Japanese shelf or near the nuclear plant."

She said it's possible that Japanese chum salmon might be in the waters near the damaged plant, but that they would not be returning to Japan for another three or four years. Japan mostly produces chum salmon, which Davis said is unlikely to be imported into British Columbia.

Davis said it is important to consider what elements are involved and what their half-life periods are, and how the salmon would come into contact with the radioactive materials.

Another SFU professor said he could not say what the effects on salmon would be.

"Given the limited information available, I cannot even speculate about the effects of radiation leaking into the ocean. It is far too early to say anything with any confidence," said Randall Peterman, SFU professor and Canada research chair in fisheries risk assessment and management.

Only two ships that left Japan just as the earthquake and tsunami were happening have arrived at Port Metro Vancouver in recent days, said Chris Badger, chief operating officer of the port.

Health Canada, the Canada Border Services Agency and Transport Canada all must approve any vessels arriving at the port. All containers go through a radiation screener, regardless of which country they've arrived from, Badger said.

Starosta predicts iodine-131 will be detected in B.C. up to three or four weeks after the Fukushima nuclear reactor stops releasing radioactivity into the atmosphere. The researchers will continue to monitor iodine-131 levels.

More than 27,000 people are dead or missing across northeast Japan after the 9.0 earthquake and tsunami, Reuters reported.



Source:
http://www.vancouversun.com/opinion/Radiation+from+Japan+reaches/4519182/story.html