Bottom-dwelling fish living near the coast of Fukushima prefecture are still contaminated with radioactive isotopes, according to a new analysis just published in the journal Science. The study suggests that the sea floor near Fukushima may be contaminated for decades to come.
More than 19 months have passed since the Fukushima Dai-ichi nuclear power station [experienced] partial meltdowns in three of its reactors and a large release of radioactive materials into the air. Winds blew some of those radioactive materials out to sea, and rain carried them down into the ocean water. In addition, water used to cool the damaged reactors flowed from the coastal power plant into the ocean. In the weeks and months after the accident, plant owner TEPCO struggled to stop leaks of contaminated water into the sea and to create a closed loop for the cooling water.
Buesseler told me that the most striking finding is that the radiation levels in these fish aren't going down. "I was struck by how they really haven’t changed over the last year," he said. He was looking specifically at the radioactive isotopes cesium-134 and cesium-137, both of which were released in the Fukushima Dai-ichi accident. "Since cesium doesn’t bioaccumulate to a significant degree, and in fact is lost when fish move to a less contaminated area, this implies that the cesium source is still there," he said. The bottom-dwelling fish are probably constantly re-contaminated by radioactive sediments layered on the seafloor, says Buesseler. And it may take decades for those sediments to be dispersed, and for the fishing area to be considered safe again.
It's also very possible that the Fukushima Dai-ichi power station is still leaking radioactive water, says Buesseler. "It could be that they’re not recovering all that cooling water, there could be leaks in the basement," he says. "Even if they’re not putting new water out, the groundwater is still contaminated."
Remember that this is only the visible part of the iceberg and many horrible things are still being hidden and need to be uncovered or recognised officially.