Enenews has a story about the detection of radioactive curium in Tochigi prefecture, 95 km from the Fukushima Daiichi nuclear plant. Curium is a neutron emitter, it undergoes spontaneous fission. Neutron emitters make the chemical elements which come into contact with them radioactive. So if you eat some of this stuff, it is like having a little nuclear reactor in the cells of your body. Neutron radiation also is a factory for manufacturing simple radioactive elements like tritium and carbon-14, which affect plants as well as humans and animals.
The table attached here shows the spontaneous fission yields of these elements. Curium has a yield around 10,000 times the yield of plutonium-240, and 1,000,000,000 times that of plutonium-239. It hangs around for a long time, the spontaneous fission half-life being around 10 million years. Seeing this stuff at such a distance from the Fuku plant is really scary.