It was the largest release of nuclear material into the ocean ever, elevating radiation levels off the coast of Japan “tens of millions times higher than normal.” Yet five years after the Fukushima nuclear disaster, radiation levels in the Pacific Ocean are showing signs of returning to normal, according to a study by the Edith Cowan University in Western Australia.
Examining radioactive caesium levels in the ocean from Japan’s coast across the Pacific to North America, a team of scientists from the Scientific Committee on Oceanic Research (co-authored by ECU Professor of Environmental Radiochemistry Pere Masqué) found levels of contamination were “decreasing rapidly.”
“Oceanic currents have dispersed the radioactive material across the Pacific Ocean as far away as North America,” said ECU’s Pere Masque.
“Radiation levels across the ocean are likely to return to levels associated with background nuclear weapon testing over the next four to five years.”
“As an example, in 2011 about of half fish samples in coastal waters off Fukushima contained unsafe levels of radioactive material however by 2015 that number had dropped to less than one per cent above the limit.”
The news is not so good for those in the immediate vicinity of Fukushima, however.
“The seafloor and harbour near the Fukushima plant are still highly contaminated and monitoring of radioactivity levels and sea life in that area must continue,” Masque said.
The Fukushima nuclear disaster was caused after a major earthquake triggered a 15-meter tsunami which disabled the power sully and cooling of three Fukushima Daichi reactors, causing a nuclear accident. Professor Masque also relayed his concerns that funds were running out for ongoing monitoring of radioactive material from Fukushima.