Groundwater radiation rose over the operator guidelines at a stricken power plant in Japan, reports said on Wednesday, leading to a halt in the groundwater being pumped into the sea.
Water from one of the 12 wells at Fukushima Daiichi Nuclear Power Station showed 1,700 becquerels of tritium per litre on Tuesday, operator Tokyo Electric Power Co said.
The company set a maximum of 1,500 becquerels of tritium in any water to be released into the sea.
Tuesday’s reading was the first above the limit since the operator started a week ago to pump water from the wells into the Pacific Ocean.
Tokyo Electric said it halted pumping on late Tuesday and would enforce monitoring. Around 560 tons of water was released last week.
World Health Organization guidelines put the safe limit in drinking water for tritium, a naturally occurring radioactive isotope of hydrogen, at 10,000 becquerels.
Groundwater seeps into the basements of the Fukushima reactor buildings on a daily basis since it was struck by the earthquake and tsunami of March 2011.
The company has also been injecting water to cool the three damaged reactors that suffered meltdowns, and storing that irradiated water in tanks on site.
