Fukushima Daiichi nuclear disaster for caesium-137, which is about 11% of Chernobyl emissions. Earlier estimations were 150 PBq and 12 PBq. In 2011, scientists working for the Japan Atomic Energy Agency, Kyoto University and other institutes, recalculated the amount of radioactive material released into the ocean: between late March through April they found a total of 15 PBq for the combined amount of iodine-131 and caesium-137, more than triple the 4.72 PBq estimated by TEPCO. The company had calculated only the direct releases into the sea. The new calculations incorporated the portion of airborne radioactive substances that entered the ocean as rain. In the
Caesium-137 forest site 50 km from the stricken plant, Cs-137 concentrations were high in leaf litter, fungi and detritivores, but low in herbivores. By the end of 2014, "Fukushima-derived radiocesium had spread into the whole western North Pacific Ocean", transported by the North Pacific current from Japan to the Gulf of Alaska. It has been measured in the surface layer down to 200 meters and south of the current area down to 400 meters. Caesium-137 is reported to be the major health concern in Fukushima. The government is under pressure to clean up radioactivity from Fukushima from as much land as