Scientists have confirmed that the first water-borne radioisotopes from the 2011 meltdown of the Fukushima nuclear power plant in Japan reached the Canadian west coast last month, almost three years after they were first released. The contaminated water was carried some 7500 km by the Kurshio Current, a major Pacific Ocean current which flows due east from Japan to British Columbia.
When Fukushima melted down, it spewed large amounts of radioactive material into the atmosphere and ocean. The following clean-up has been riddled with setbacks. In late February, for instance, the power plant’s once-operator Tokyo Electric reported that it had spilt 100 tonnes of highly contaminated water after attempting to fill an already-full storage container. While they claim that “water is unlikely to reach the ocean” due to lack of drainage around the container, this is merely the latest in a series of leaks which has sent even more radiation into the environment.
Due to the nature of the currents in the Pacific Ocean, British Columbia is the first coastline to receive the contaminated water, but it is expected that it will now spread both up towards Alaska and down towards Washington state and beyond. The radiation being output by Fukushima is uniquely identifiable from other sources of radiation due to the presence of caesium-134, a fast-decaying isotope with a half-life of only 2 years. This half-life is so short that there is essentially no naturally occurring caesium-134, while the caesium-134 created during Cold-War era weapons testing has all decayed; the only significant source of caesium-134 in the oceans right now is Fukushima.
Experts are quick to note that the radiation levels in the water is incredibly minimal, and poses absolutely no threat to the environment or human health. Current predictions suggest that the radiation levels will peak at between 2 and 27 Becquerels/m3, far less than the safety limit for drinking water of 7400 Becquerels/m3 set by the US government. Ken Buesseler, of the Woods Hole Oceanographic Institute, has even suggested that studying the movement of the Fukushima radiation could provide a wealth of information about Pacific Ocean currents. To this end, he launched a website, ourradioactiveocean.org, where people can make donations to support the collection and analysis of water samples.
There was plenty of advanced warning about the incoming radiation from Fukushima thanks to the Canada’s Department of Oceans and Fisheries, which had been monitoring radiation levels up to 1500 km from Vancouver. However, initial estimates expected the radiation to still be months, if not years, away from making landfall. One theory for the discrepancy between the models and reality is provided by John Smith, a chemical oceanographer from the Bedford Institute of Oceanography. He suggests that the contaminants currently being seen were not discharged into the water at Fukushima, but instead were blown some distance eastward by the wind before falling into the ocean.
Fukushima has been described as the worst nuclear disaster since the catastrophic meltdown of the Soviet Chernobyl reactor, and some suggest that it is actually worse. And while there are still many questions about the effects of low level radiation on human health, it is unlikely that North American residents will have anything to fear; Fukushima has only produced a slight increase in radiation over background levels. Nevertheless, the accident has already rejuvenated long-standing arguments about nuclear safety. That fact that radioactive water has now made it to Canada is sure to inspire even more debate.
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