Studies on radiocesium transfer in agricultural plants in Fukushima prefecture

Abstract

After the Fukushima Daiichi Nuclear Power Plant (Tokyo Electric Power Company) accident occurred in March 2011, the concentration of radiocesium in brown rice produced in several areas of Fukushima Prefecture has exceeded a provisional regulation value. Therefore, we attempted research on decreasing the radiocesium concentration in agricultural plants. To decrease the concentration of radiocesium in brown rice, we investigated the effect of the application of potassium fertilizer in rice paddy fi elds on the root uptake of radiocesium. The soil-to-brown-rice transfer factor of radiocesium decreased with an increase in exchangeable K 2 O in the soil, suggesting that the application of potassium fertilizer is an effective countermeasure to reduce the radiocesium concentration in brown rice. We examine the possibility of decontamination by means of phytoremediation. Four species of plants were sown. The highest removal percentages of 137 Cs were obtained in amaranth (0.093 %) and sunfl ower (0.038 %) in the light-colored Andosol and gray lowland soils, respectively. This result indicates that it is diffi cult to remove radiocesium from contaminated soil by means of phytoremediation.