Tokyo Electric Power Co. (TEPCO) said that radioactive Materials were detected from the seawater around the discharge canal (south) of Fukushima Daiichi Nuclear Power Station, which was damaged by earthquake on March 11.
The radioactive materials were detected after authorities began testing for radiation in sea water.
Reactors at the Fukushima Daiichi plant, which lies 150 miles north of Tokyo, have leaked radiation after they were struck on March 11 by a massive earthquake and tsunami, leading to the world's worst nuclear crisis since Chernobyl 25 years ago.
Workers have sprayed tones of sea-water to cool down the reactors at the nuke plant. But, several experts have questioned what happens to the sea-water after that.
TEPCO, which had informed the development to Nuclear and Industrial Safety Agency (NISA) and Fukushima prefecture, will also conduct a similar test at Fukushima Daini Nuclear Power Station to examine radioactive materials spread into the sea.
Meanwhile, levels of radioactive iodine-131 in sea-water samples near the plant on Monday were 126.7 times higher than the limit, Kyodo news agency reported quoting TEPCO. Levels of cesium-134 were 24.8 times higher and those of cesium-137 16.5 times higher while a trace amount of cobalt 58 were detected, it said.