Japan's nuclear watchdog says there is a
new state of emergency:
An official from the Nuclear Regulation Authority says contaminated groundwater has risen above a shore barrier meant to contain it and is seeping into the Pacific Ocean.
Speaking to the Reuters news agency, Shinji Kinjo revealed the leak is exceeding legal limits of radioactive discharge.
Countermeasures planned by Tokyo Electric Power Co (TEPCO), the operator of the Fukushima nuclear complex, are only a temporary solution, Mr Kinjo added.
"Right now, we have an emergency," he said.
How will this impact the Pacific?
It was not immediately clear how much of a threat the contaminated groundwater could pose. In the early weeks of the disaster the Japanese government allowed Tepco to dump tens of thousands of tonnes of contaminated water into the Pacific as an emergency measure.
The toxic water release was heavily criticised by neighbouring countries as well as fishermen and the utility has since promised not to dump irradiated water without the consent of local townships.
"Until we know the exact density and volume of the water that's flowing out I honestly can't speculate on the impact on the sea," said Mitsuo Uematsu, of the Centre for International Collaboration, Atmosphere and Ocean Research Institute at the University of Tokyo.
In the US, across the Pacific, there was no sense of alarm. "With the amount of dilution that would occur, any kind of release in Japan would be non-detectable here," said David Yogi, spokesman for the US Environmental Protection Agency.
Not so fast, David Yogi.
Radiation was detected after the initial Fukushima accident:
Radioactive cesium was detected in samples of highly prized Pacific bluefin tuna, but it is well below levels considered unsafe for humans, the scientists say.
The evidence is "unequivocal" that the tuna - caught off San Diego a year ago - were contaminated with radiation from Japan's nuclear disaster, the researchers said.
Virtually all bluefin tuna on the market in the United States is either farmed or caught far from the Fukushima area, so American consumers should not be affected by radiation contamination in their fish, seafood distributors say. The migratory bluefin studied by the researchers were all caught by sport fishermen and were not headed for the market.