Since the first explosion occurred at the troubled Fukushima Daiichi nuclear power plant on March 12, steam and smoke carrying radioactive iodine and cesium has been blowing east, out to sea. General opinion has been that it is fortunate the cloud is over the ocean, not forming over the rest of Japan or China. However, the consequence for marine life and ocean water could be equally harmful in the long run.
Last week, the Japanese government reported that higher than normal levels of radioactivity was detected in rainwater in Tokyo. Radioactive rain has almost certainly been falling into the ocean as well.
The International Atomic Energy Agency (IAEA) has detected radiation 18 miles out to sea, but said, according to the latest readings taken on March 27, that levels have been dropping from what they saw days earlier.
“It can be expected that the data will be quite variable in the near future depending on the discharge levels. In general, dilutions by ocean currents and into deeper waters as well decay of short lived radionuclides e.g. I-131 or I-132 will soon lead to lower values,” according to the IAEA’s March 29 update.
Trenches have been built at the Fukushima Daiichi plant to prevent the radioactive water used in cooling from flowing into the ocean. Officials said Tuesday that the levels of water in trenches a mile from shore have remained stable, but they are contaminated and they are still not sure how the contamination got there.
The IAEA says dispersion of the radioactivity through the ocean will take months or years to reach other Pacific countries. The main transport of contamination across long distances is through the air, said the agency, where it will likely be diluted.
Scientists at Simon Fraser University, in British Columbia, Canada, found iodine-131—a byproduct of nuclear fission—in the southern portion of Canada’s west-most province on March 19, 20, and 25. Nuclear physicist Kris Starosta told a press conference that the levels being seeing are not harmful to humans, but that the contamination certainly came from Fukushima, travelling to North American via a jet stream that crosses the Pacific Ocean.
Although the effects of radioactive elements in the ocean may not be immediately observable, the size of the ocean should not be viewed as sufficient to dilute the radioactive waste.
“The vastness of the ocean is often taken to mean that it has an enormous power to dilute most of man’s wastes. That is a misconception that led most nuclear powers to dump radioactive waste into the ocean, before doing so was banned by international treaty in the 1970s,” wrote Jacob Hamblin via e-mail. Hamblin teaches history of science at Oregon State University and has researched and written about the history of dumping nuclear waste in the ocean.