VANCOUVER — 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.
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, B.C., campus and in downtown Vancouver, while seaweed samples were collected in North Vancouver, B.C.
"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, the SFU statement said.
More than 27,000 people are reported dead or missing across northeast Japan after the 9.0 earthquake and ensuing tsunami, which damaged the Fukushima Daiichi nuclear facility.
The situation at the six-reactor complex remains "very serious," the International Atomic Energy Agency said 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 reported.
When asked what effect this emission 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," Starosta said.
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 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 very unlikely to be imported into British Columbia.
Davis said it is important to consider what elements are involved and what their half-lifes are, and how the salmon would come into contact with the radioactive materials.
SFU professor Randall Peterman said it's too early to say what the effects of the radiation leaks could 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 Peterman, Canada Research Chair in fisheries risk assessment and management.
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.