2015 Volume 84 Issue 1 Pages 9-16
The purpose of this research was to examine the practicality of phytoremediation for removing radioactive cesium from the soil polluted by the Fukushima Daiichi Nuclear Power Plant accident. We measured the concentration of radioactive Cesium (Cs134 and Cs137, hereafter referred to as Cs) in each plant organ and the dry matter weight of plants cultivated in the field in Kawamata town of Fukushima prefecture in 2011, 2012 and 2013. Radioactive Cs concentration was higher in amaranth(Amaranthus spp.) than in kenaf (Hibiscus cannabinus) in all three years, but there was no difference among amaranth species. In addition, the concentration of radioactive Cs was higher in amaranth in the paddy field than in that in the upland field at the same location. This was probably because the lower potassium concentration in the paddy soil enhanced the uptake of Cs. On the other hand, the dry matter weight of amaranth in the upland field was higher than in that in the paddy field. The radioactive Cs concentration was highest in the leaves and lowest in the seed. For amaranth, the transfer factor of Cs in the plant from the soil was from 0.020 to 0.354 lower than the results obtained from amaranth experiments using the soil obtained from the Chernobyl exclusion zone. The removal rate of Cs from the soil by one time cultivation of amaranth was also low ranging from 0.019% to 0.283%. In conclusion, phytoremediation of Cs by amaranth cultivation was not practical.
