Fukushima finds cesium in Nihonmatsu rice, to hold more tests before shipment decision
The Fukushima Prefectural Government said on Sept. 23 that it had detected 500 becquerels of radioactive cesium per kilogram -- the government-set allowable limit -- in a sample of "Hitomebore" rice collected in Nihonmatsu's Obama district. It will greatly increase the number of testing locations there for a second test to decide whether to allow shipments of rice from the city.
After discovering radioactive cesium in the rice crop from the city, Nihonmatsu became the first area to be designated a "priority test area," which means the local government will increase the number of locations in the city where rice crops are tested for radioactive substances before deciding whether to allow shipments.
Early-season rice from across Fukushima Prefecture was already previously approved for shipments, and some municipalities have started shipping their regular season rice. The test results from Nihonmatsu have again stirred worries among farmers and others about effects on Fukushima products' reputation.
According to the prefectural government, 500 becquerels of radioactive cesium were detected in a rice sample collected on Sept. 12, and soil in its paddy field contained 3,000 becquerels of cesium per kilogram. Rice crops from 11 other locations in the Obama district had from undetectable amounts up to 212 becquerels of cesium.
Preliminary tests such as the one that found the problem rice in Nihonmatsu are being conducted about one week before harvesting in 370 zones covering the whole prefecture. Those municipalities where rice with 200 becquerels or more of cesium are found are designated as "priority test areas." Such areas get two testing locations per 15 hectares of land for a later second test that determines whether shipments from the zone will be allowed.
Following the Nihonmatsu test results, the Fukushima Prefectural Government plans to increase the number of testing locations there from around 40 to around 300. If rice with 500 becquerels or more cesium per kilogram is again found, shipments of all rice crops from that part of the city will be restricted.
Before the Nihonmatsu finding, the highest level of cesium detected in ordinary rice from Fukushima Prefecture in preliminary tests was 136 becquerels in Fukushima city's Onami district.
The Ministry of Agriculture, Forestry and Fisheries estimated the transfer coefficient of cesium from soil to rice crops at 0.1 (10 percent) and banned planting rice in paddy fields with more than 5,000 becquerels of cesium per kilogram of soil. Based on these values, in theory rice from the prefecture should not contain more than 500 becquerels of cesium.