More than 30 hotspots of radioactive cesium concentrations have been discovered in the Pacific Ocean, as far as Abukuma River in Miyagi Prefecture, 70 km north of the Fukushima No. 1 nuclear plant.
According to the Japan Times, a research team led by the University of Tokyo has concluded that cesium-137 gets easily absorbed in clayish soil and concentrates in seabed depressions.
A 70 meters wide hot spot has been found 32 meters below the ocean surface, 5.9 km away from the plant, containing radioactive cesium concentrations of 651 becquerels per kilogram, the team said.
The research team even found a hot spot with average concentrations of 1,029 becquerels of cesium-137 per kilogram of mud, 1.6 km east of the Abukuma River estuary.
Abukuma river runs through both Fukushima and Miyagi prefectures, and the research team believes radioactive cesium was carried by the river to the hot spots in the sea.
It has also been reported that contractors doing decontamination work at the reactors have dumped their debris in rivers.
Blair Thornton, a special associate professor at the university, said that the findings will be shared with fishery researchers for determining the possible effect of radioactive contamination on marine life.
