TOKYO (majirox news) — Radioactive hotspots have been found in prefectures neighboring Tokyo with levels of cesium rivaling those found in the least contaminated parts of Fukushima prefecture, according to the Ministry of Education, Culture, Sports, Science and Technology (MEXT).
MEXT released radiation maps of Chiba and Saitama prefectures, both of which neighbor Tokyo, as part of its plan to draw up a visual guide to radiation levels across all of eastern Japan in the wake of the Fukushima Daiichi nuclear crisis.
In a region covering about 10,000 square hectares (38 square miles) of Chiba prefecture and including cities such as Kashiwa and Abiko, levels of cesium 134 and 137 were found in the 60,000 to 100,000 becquerel range – about the same as the least contaminated parts of Fukushima prefecture. Cesium 134 and 137 are by-products of the radiation the core of a nuclear reactor produces.
Cesium 134 breakdowns relatively quickly, but cesium 137 does not, according to the Argonne National Laboratory. In the aftermath of the 1986 nuclear accident in Chernobyl, areas where radioactivity levels exceeded 37,000 becquerels were designated as contamination zones, according to the Asahi newspaper.
Areas around Kashiwa were confirmed as hotspots, where radioactivity is higher than places surrounding them, and cesium has been found in the soil. High levels of cesium in soil were also confirmed in an area south of the Saitama prefecture city of Chichibu.
MEXT believes these areas became contaminated as radioactive particles were soaked up by clouds, blown by the wind and fell to the ground with rain.