The content of caesium-134 and caesium-137 isotopes per litre of water has made 267 thousand Bq at the first and second nuclear power units, Tokyo Electric Power operating Fukushima-1 said on Monday.
A sharp radiation growth is explained by the spread of contaminated particles in the ground water due to heavy rain triggered by typhoons Phanfone and Vongfong.
In March 2011 a strong earthquake triggered a high tsunami off the north-eastern coast of Japan. A gigantic wave hit the nuclear power plant Fukushima-1 that resulted in the most devastating nuclear disaster since the Chernobyl nuclear power plant catastrophe in 1986. Last week the highest radiation level was fixed in the water sample after the nuclear disaster, as caesium isotope content has made 251 thousand Bq at the moment of the emergency situation. Current figures exceeded that radiation level.