Toshihiro Takatsuji, associate professor at Nagasaki University announced the result of his measurement of radioactive cesium in the air at an international symposium, and said a high level of cesium-134 (11,300 becquerels/kg) was detected from the dust collected in the filter paper in early April last year in Nagasaki City, 1,000 kilometers away from Fukushima I Nuclear Power Plant.
It took him 9 months to reveal what he had known in April last year. Not bad, I guess, considering there are many others who still hold back information that they obtained in March and April last year while they eagerly wait for the acceptance of their papers at international peer-review journals. Some information could have made a big difference in how people responded to the nuclear crisis if it had been revealed in a timely manner.
But maybe not in this case, as I cannot compare this number with any other number. How about the measurement of air filter papers in Fukushima or Tokyo during the same time period? How about the measurement in Nagasaki prior to the nuclear accident? What are we comparing this Nagasaki number to?
Chugoku Shinbun (1/26/2012):
It has been revealed that the suction survey at an atmospheric observatory in Nagasaki City, about 1000 kilomters from Fukushima I Nuclear Power Plant, showed a high level of radioactive materials one month after the nuclear accident. Toshihiro Takatsuji, associate professor at Nagasaki University reported at an international symposium by Hiroshima University Research Institute of Radiation Biology and Medicine (RIRBM) held on January 25 at Hiroshima University in Hiroshima City.
Professor Takatsuji measured the amount of radioactive cesium in the air captured by the air suction apparatus and on the filter paper at the suction entrance every week after the nuclear accident. He reported the results from March 23 to July 27, 2011.
The week beginning on April 6 registered the highest level of radioactive cesium. The density of cesium-134 on the dust caught by the filter paper was 11,300 becquerels/kg, equivalent to the level seen in the soil in Iitate-mura in Fukushima Prefecture.
Professor Takatsuji pointed out that on April 6, 2011, the wind reached from Tohoku to Kyushu (where Nagasaki is located) in an arc sweeping the Pacific side of Japan, according to the data from the US National Oceanic and Atmospheric Administration (NOAA). He deemed the radioactive cesium to be of Fukushima origin.
The professor said, "Even if the amount in the atmosphere is low, it is possible that radioactive materials accumulate in the air filters." The symposium will continue on January 26.
11,300 becquerels/kg of cesium-134. No information about cesium-137, if it was detected at all in the air or on the filter paper.
I dispute the reference to Iitate-mura, though. From what I have read, the density of radioactive cesium in Iitate-mura's soil is much higher (50,000 becquerels/kg of radioactive cesium).
As an aside, Professor Takatsuji has been featured in a popular weekly Shukan Gendai magazine (as transcribed in this blog) in which, with Shinzo Kimura he assures the readers that the effect of radiation won't manifest in genes in the next generation, so the fear of expecting mothers in Fukushima is overblown.
But even the two admit that by continuing to live in the areas with elevated radiation levels the gene mutation which normally happens after 10 generations or more may happen within a few generation.