From the UK Telegraph:
Japan's prime minister has declared a state of "maximum alert" over the country's nuclear disaster after highly toxic plutonium was found to have leaked into the soil from the plant.
Naoto Kan told the Japanese parliament that the combined 9.0 magnitude earthquake, tsunami and nuclear accident were the "biggest crises" in decades.
"From now on, we will continue to handle it in a state of maximum alert," he said.
Mr Kan's comments came after the Tokyo Electric Power Company (Tepco), the operators of the Fukushima plant, confirmed that plutonium had been detected for the first time in two out of five soil samples.
Tepco said the levels of plutonium were not harmful to human health, but experts said the discovery raised concerns that the reactor's containment mechanism had been breached.
"Plutonium is a substance that's emitted when the temperature is high, and it's also heavy and so does not leak out easily," said Hidehiko Nishiyama, deputy director of Japan's Nuclear and Industrial Safety Agency.
"So if plutonium has emerged from the reactor, that tells us something about the damage to the fuel. And if it has breached the original containment system, it underlines the gravity and seriousness of this accident."
It is thought that some of the plutonium may have entered the soil from spent fuel rods at the plant or due to damage to reactor Number 3, the only one using the substance in its fuel mix.
Used in nuclear bombs and a by-product of atomic reactions, plutonium is an extremely dangerous radioactive element.....read on