Wind directions in Japan are currently blowing radiation from the troubled Fukushima nuclear power plant eastwards out to the Pacific Ocean (see Figure 1), but a shift in directions Sunday risks sending the radiation plume towards Tokyo (see Figure 2). These models have just been published in a bulletin by Austria’s weather service, the Central Institute for Meteorology and Geodynamics in Vienna.

On the colour scale, red represents 100 millisieverts per hour (100 mSv/hr), and purple a maximum of 100 nanosieverts per hour (.0001 mSv/hr). For an explanation of the units see “”https://blogs.nature.com/news/thegreatbeyond/2011/03/fukushima_crisis_radiation_exp.html">Radiation exposure, beyond the numbers". In terms of dose, an exposure of 100mSv is enough to slightly increase the chances of developing cancer later in life; a dose of 100 nanosieverts is neglegible.

Figure 1: Plume as of today, and tomorrow.

<IMG SRC=“https://www.zamg.ac.at/pict/aktuell/20110318_bild1_2.gif”

Figure 2: Plume as of Sunday

<IMG SRC=“https://www.zamg.ac.at/pict/aktuell/20110318_fuku_I-131-Bild3.gif”

There is also some radionuclide data coming out of station RN38, in Takasaki/Gunma. The station is operated by the Comprehensive Test Ban Treaty Organization (CTBTO) (see the long article I published yesterday on CTBTO data for more details on its data) and recorded many species of radionuclides on 15 March, including iodine-131 and Barium-140, with a preliminary estimate of the concentration of iodine-131 at 15 becquerels per cubic meter. That’s a fairly low dose. Radioactive iodine-131 was also detected at the Petropavlovsk station in Russia, but at fourfold-lower levels. That should pose no threat to human health, though its very presence is troubling.

Below is an animation of the plume’s predicted path:

For full coverage of the Fukushima disaster, go to Nature’s news special.

Images: Central Institute for Meteorology and Geodynamics