Workers at the plant are conducting daily radioactivity checks of water in the ditch.
The measure is to examine the effects of contaminated water leaks from storage tanks.Officials at the Tokyo Electric Power Company say they detected 1,400 becquerels per liter of beta ray-emitting radioactive material at a measuring point 150 meters from the sea on Wednesday.
The figure was more than 70 times higher than readings taken on Tuesday. It's also the highest since monitoring of the ditch water was started in August.
Officials say rain from the typhoon caused contaminated soil to flow into the ditch and created the high radioactivity.They say they will begin a cleanup operation.Officials also say they will assess the effects on the surrounding sea. Oct. 17, 2013 - Updated 02:56