Tokyo Electric Power Co. officials revealed today that they have detected plutonium in the soil at five locations near the crippled Fukushima Daiichi nuclear reactors. But don't get all alarmist or anything, because it's not a lot of plutonium...

While noting that the concentration level does not pose a risk to human health, the utility firm said it will strengthen monitoring on the environment in and around the nuclear plant.

That said, the presence of plutonium contamination is pretty much conclusive evidence that there has been at least some damage to the fuel rods in the No. 3 reactor, the only one at the plant to use mixed-oxide plutonium/uranium fuel. CNN reports that "three types of plutonium" have turned up in the soil samples, but again, nothing to worry about, as Pu-239 has a half-life of only 24,100 years.

Japan's Nuclear Safety Commission also now presumes at least a partial meltdown at the No. 2 reactor as the likely source of the highly radioactive pools of water that have now been found on site. Radiation levels "exceeding 1000 millisieverts per hour" have now been measured in a trench outside the No. 2 reactor building, leading to today's duh-uh moment:

Although it remains unknown whether the contaminated water has flowed into the sea from the trenches that are 55 to 70 meters away from the shore, TEPCO suspects the high concentration of radioactive substances found in seawater near the plant reactors' drainage outlets may be linked to the trench water.

No shit Sherlock.

TEPCO officials strenuously deny having concealed data amidst growing complaints over the timeliness and accuracy of their reports.

Meanwhile in Tokyo, the cherry trees have started blooming. Just thought I'd close this on a positive note.