Now the government scientists have some explaining to do, because the soil at that location contained only 3,000 becquerels/kg of radioactive cesium. The government has used the transfer rate of cesium from soil to rice at 0.1, but in this particular instance, if we believe the number for the soil contamination the transfer rate is more like 0.17.
Nihonmatsu City where the 500bq/kg rice was found is located at about 55 kilometers west from Fukushima I Nuclear Power Plant.
Yomiuri Shinbun linked below says it was from Iwashiro District that the radioactive rice was found. But according to the Fukushima prefectural data, the district is not Iwashiro District but Obama District.
From the surveys that have been done so far on rice in locations in Tohoku and Kanto, the transfer rate has been between 0.001 to 0.01, which is what the agricultural scientists have been saying from the beginning.
From Yomiuri Shinbun (1:06AM JST 9/24/2011):
On September 23 Fukushima Prefecture announced the result of the preliminary survey of regular rice, and said one sample from Nihonmatsu City was found with 500 becquerels/kg of radioactive cesium. The level is the same as the national provisional safety limit.
Since the level exceeded 200 becquerels/kg, which is a standard used to determine whether more rigorous survey is necessary, the entire city of Nihonmatsu is designated as "special survey area", and 300 locations in the city will be tested instead of the planned 38 locations when the real survey starts. It is the first time a "special survey area" is designated.
Radioactive cesium exceeding the standard (of 200 becquerels/kg for "special survey area") was found from the rice sample taken on September 12 from a location in Iwashiro District in Nihonmatsu City. The density of radioactive materials [cesium] in the soil in the rice paddy where the rice was harvested was 3,000 becquerels/kg. 18 other samples from the same city all tested below the standard.
Old municipalities [now incorporated into a bigger city, as in the case of Iwashiro District] whose samples all test below the standard [200 becquerels/kg] in the preliminary survey will only need to test 2 samples per district, and if the 2 samples test below the standard the shipment of rice from the entire district will be allowed. In a "special survey area", 2 samples from every 15 hectares will be tested. If all samples test below the national provisional safety limit, then the shipment of rice from the district will be allowed. If one sample exceed the provisional safety limit, the shipment is banned for the entire district.
In Japanese, this type of testing is called "ざる" - pronounced "za-ru" - sieve. It still caught 500 becquerels/kg cesium rice, to the dismay of Fukushima producers and the prefectural government.
Well well. The Fukushima prefectural government sat on the data for 8 days. This particular sample was taken on September 12 along with other samples in Nihonmatsu City, and the other results were published on September 15, which showed the level of radioactive cesium between ND and 61 becquerels/kg.