Department of Biology, Graduate School of Science, Kobe University, Rokkodai, Nada, Kobe, 657-8501, Japan,
J Plant Res. 2014;127(1):5-10. doi: 10.1007/s10265-013-0599-6. Epub 2013 Dec 8.
The radionuclide status of wild plants and soil in the Fukushima area was investigated during the period May 2011 to October 2012, using an imaging plate (autoradiograms) or a high purity germanium detector. Analyses of autoradiograms showed that wild plants grown in March 2011 were strongly polluted with fallout released from the Fukushima 1 Nuclear Power Plant. The radioactivity was mostly due to fallout adsorbed on the surface of the plants. On the other hand, a number of herbaceous plants were regularly collected in the Fukushima area and their radionuclide concentrations were measured with a high-purity germanium detector. Plants grown in March 2011 showed very high levels of ¹³⁴Cs and ¹³⁷Cs, but these radioactivity levels decreased rapidly after July 2011 and eventually became lower than that of endogenous ⁴⁰K. During this period, the radioactivity of the soil remained high. We therefore suppose that a significant proportion of the radioactivity detected from plants harvested after July 2011 was most likely derived from soil dust attached on the plant surface. Autoradiograms of rice plants were virtually identical between plants cultivated in Fukushima and Osaka area, reflecting the background radiation due to ⁴⁰K.
2011 年 5 月至 2012 年 10 月期间，使用成像板（放射自显影）或高纯锗探测器调查了福岛地区野生植物和土壤中的放射性核素状况。放射自显影分析表明，2011 年 3 月生长的野生植物受到了福岛第一核电站释放的沉降物的强烈污染。放射性主要是由于沉降物吸附在植物表面。另一方面，定期在福岛地区采集了一些草本植物，并使用高纯锗探测器测量了它们的放射性核素浓度。2011 年 3 月生长的植物显示出非常高的 ¹³⁴Cs 和 ¹³⁷Cs 水平，但这些放射性水平自 2011 年 7 月后迅速下降，最终低于内源性 ⁴⁰K。在此期间，土壤的放射性仍然很高。因此，我们假设，2011 年 7 月后收获的植物中检测到的放射性的很大一部分很可能来自附着在植物表面的土壤尘埃。在福岛和大阪地区种植的水稻植株的放射自显影图几乎相同，反映了 ⁴⁰K 引起的背景辐射。
