This computer model of the Fukushima radiation plume shows its expected progress across the Pacific Ocean.
The first signs of radioactive isotopes from the damaged Fukushima nuclear power plant have been detected in the waters off western Canada, and their early arrival is giving scientists insights into ocean currents and how they can improve their attempts to model the progress of these isotopes.
When the Fukushima Daiichi nuclear power plant was damaged in a devastating March 2011 earthquake, scientists began monitoring the ocean waters in the Pacific for the radioactive elements released by the plant — specifically the isotopes cesium-137 and cesium-134. Cesium-137 is already present in seawater, left over from various nuclear weapon tests performed during the '50s and '60s, so detecting that isotope alone isn't unusual. However, as of June 2013, researchers at the Bedford Institute of Oceanography detected levels of both isotopes along the British Columbia coastline, showing a clear signal that this was radiation specifically from the Fukushima disaster.
Dr. John Smith with the Bedford Institute and Dr. Ken Buesseler from the Woods Hole Oceanographic Institution in the U.S. presented their findings on this at the 2014 Ocean Sciences Meeting in Hawaii this week.
The levels of radiation detected in seawater along the BC coast as of June 2013 were less than one becquerel per cubic metre (one becquerel is one atom undergoing radioactive decay per second). However, it should be stressed that these are extremely low levels.
Speaking to BBC News, Smith said: "These levels are still well below maximum permissible concentrations in drinking water in Canada for cesium-137 of 10,000 becquerels per cubic metre of water — so, it's clearly not an environmental or human-health radiological threat."
The models designed to predict the levels of radiation have varied. One model showed that the maximum peak of radiation along the North American west coast would be around two becquerels per cubic metre, while another had the peak up around 27 becquerels per cubic metre (both still extremely low levels). The timing has been off as well, with the radiation actually starting to show up roughly two years before it was predicted from one model. However, with levels of radiation from Fukushima showing up sooner than expected, it's giving the scientists a chance to determine which model did better, and it should allow them to refine the models to give better predictions.
"It's interesting: if this was of greater health concern, we’d be very worried about these factors of ten differences in the models," Buesseler said, according to BBC News, as he spoke to reporters about the performance of the models. "To my mind, this is not really acceptable. We need better studies and resources to do a better job, because there are many reactors on coasts and rivers and if we can't predict within a factor of 10 what cesium or some other isotope is downstream — I think that’s a pretty poor job."
While these radioactive isotopes from Fukushima have been detected off the coast of British Columbia, none have been detected yet off the coast of the United States.
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Although some argue that any level of radiation is damaging to the cells in our body, it's important to understand that we deal with radiation every day of our lives. This isn't referring to cellphone or any other kind of electronics. Simply by standing in an open empty field we're exposed to radiation from our environment, and many of the foods we eat every day contain naturally-occurring radioactive elements.
The maximum predicted radiation level from Fukushima along the Pacific coast of North America is about 27 becquerels per cubic metre of water. If we took that water, poured out enough to tip the scale at 1 kilogram, and then put it beside a kilogram of white potatoes (for example), we would find that the potatoes emitted over 4,600 times the amount of radiation than was detected from the water (due to the naturally-occurring radioactive potassium in the potatoes). Even so, that amount of radioactivity from the potatoes is something that our bodies can easily deal with on a regular basis, and the tiny amount from cesium in the water is insignificant.
(Image courtesy: Woods Hole Oceanographic Institution via YouTube)
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