Continuing leaks and contaminated sediment keep radiation levels high.
[…] New data presented at a conference held on 12–13 November at the University of Tokyo show that levels of radioactivity in the sea around the plant remain stable, rather than falling as expected. […]
The Fukushima disaster caused by far the largest discharge of radioactivity into the ocean ever seen. A new model presented by scientists from Woods Hole Oceanographic Institution in Massachusetts estimates that 16.2 petabecquerels (1015 becquerels) of radioactive caesium leaked from the plant — roughly the same amount that went into the atmosphere.
[…] in the region of the ocean near the plant, levels of caesium-137 have remained fixed at around 1,000 becquerels, a relatively high level compared to the natural background. […]
Researchers at the conference are convinced that something is preventing the radiation levels from dropping. “There must be a source,” says Scott Fowler, an oceanographer at Stony Brook University in New York.
In fact, a fresh analysis by oceanographer Jota Kanda at the Tokyo University of Marine Science [estimates] the plant itself is leaking around 0.3 terabecquerels [0.3 trillion becquerels] per month […]