Excerpt on Radiation from IAEA Briefing on Fukushima Nuclear Accident (5 April 2011, 14:00 UTC)

On 3rd April, deposition of both iodine-131 and cesium-137 was detected in 7 prefectures. The values for iodine-131 ranged from 2.4 to 82, for cesium-137 from 5.2 to 57 becquerel per square metre. On 4th April, deposition of iodine-131 was detected in 7 prefectures ranging from 3.1 to 75 becquerel per square metre. Deposition of cesium-137 in 6 prefectures ranging from 7.4 to 46 becquerel per square metre. Reported gamma dose rates in the 46 prefectures showed no significant changes compared to yesterday. As of 3rd April, iodine-131 and cesium-134/137 was detectable in 8 and 5 prefectures respectively. All values were well below levels that would trigger recommendations for restrictions of drinking water. As of 3rd April, restrictions for infants related to I-131 (100 Bq/l) are in place in only one village of the Fukushima prefecture. The restriction is still in place as a precautionary measure. Currently, the IAEA monitoring team is working in the Fukushima region. On 5th April, measurements were made at 7 locations at distances of 16 to 41 km, South and South West to the Fukushima nuclear power plant. The dose rates ranged from 0.3 to 31 microsievert per hour. At the same locations, results of beta-gamma contamination measurements ranged from 0.01 to 3.2 megabecquerel per square metre. The highest dose rates and beta gamma contaminations were measured at the location closest to the Fukushima Nuclear Power Plant. Since our written briefing of yesterday, data related to food contamination was reported on 4 April by the Japanese Ministry of Health, Labour and Welfare. These reported analytical results covered a total of 24 samples taken on 31 March (4 samples) and 1st, 3rd and 4th April (20 samples). Analytical results for all of the 24 samples for various vegetables, fruit (strawberry) and seafood in five prefectures (Gunma, Ibaraki, Niigata, Saitama and Tochigi) indicated that iodine-131, caesium-134 and/or caesium-137 were either not detected or were below the regulation values set by the Japanese authorities. ... Seawater is collected daily close to the discharge areas of Units 1 - 4 and of Units 5 and 6 at the Dai-ichi NPP. The data show a d…