NEWS RELEASE · 29th March 2011
Simon Fraser University
Simon Fraser University researchers are attributing increased levels of the radioisotope iodine-131 in B.C. seaweed and rainwater samples to the Fukushima Dai-Ichi nuclear reactor situation in Japan.
Japanese officials have been working to prevent a nuclear meltdown after cooling systems failed following a magnitude 9.0 earthquake earlier this month that was accompanied by a tsunami. Medical and pharmaceutical industries use iodine-131; it’s also present in nuclear fission products.
SFU nuclear scientist Kris Starosta is confident Fukushima is responsible for the recent discovery, but he cautions 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 explains. “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 jet stream is carrying the radiation from Japan to North America. Most of the radioactivity disperses in the atmosphere and falls over the Pacific Ocean on its way over, but some of it has now reached the west coast, falling down with rain, and mixing with seawater. It’s also accumulating in seaweed.
The rainwater tested was collected at SFU’s campus on Burnaby Mountain and in downtown Vancouver, while seaweed samples were collected in North Vancouver near the Seabus terminal. Researchers began monitoring rainwater earlier this month but did not see the signature for iodine-131 in samples taken March 16 and March 18. However, they did detect the radioisotope’s signature in samples from March 19, 20 and 25.
Here are the results from the tests (measured in decays of iodine-131 per second per litre of rainwater – Bq/l):
• March 18: 0 (2) Bq/l
• March 19: 9 (2) Bq/l
• March 20: 12 (2) Bq/l
• March 25: 11 (2) Bq/l
“The only possible source of iodine-131 in the atmosphere is a release from a nuclear fission,” says Starosta. “Iodine-131 has a half life of eight days, thus we conclude the only possible release which could happen is from the Fukushima incident.”
Starosta and his team of SFU researchers – Rachel Ashley, Aaron Chester, Svetlana Avramova and Ken Myrtle – will continue monitoring iodine-131 levels. Seaweed samples taken from Barkley Sound on Vancouver Island’s west coast are also being tested. Starosta predicts iodine-131 will be detected in B.C. 3-4 weeks after the Fukushima nuclear reactor stops releasing radioactivity into the atmosphere.
From Smith College slide presentation on direction and implications of fallout
Japan shows record radiation in seawater
Comment by M Craven on 30th March 2011
Nuclear safety officials have announced that seawater outside the plant contains 3,335 times the usual amount of radioactive iodine — the highest rate yet and a sign that more contaminated water has make its way into the ocean. The nuclear disaster is stretching into it's third week. I am sure glad that Canadian Politicians have taken me seriously enough to let this issue go unnoticed. I have been editing internal reports and I know the situation is far from over. It will effect BC if the leakage continues, I sure hope everyone enjoys salmon that glows in the dark.
Comment by Pat on 30th March 2011
haiti is still amess, there are wars everywhere, uprisings for freedom happening I type and now this.
Hasn't Japan been subjected to enough crap alraedy?
Everyday ... when I think I have it so bad ... I think of all above.