[3J01-08] Fukushima 1

[3J07] Investigation on distributino of radioactive substances in Fukushima

(7) Estimation of dissolved Cs-137 discharge flux by shallow groundwater in forest hillslope

*Yuma Niwano¹, Hiroaki Kato¹, Donovan Anderson¹, Hikaru Sato¹, Hikaru Iida¹, Miyu Nakanishi¹, Yuichi Onda¹ (1. University of Tsukuba)

Keywords:Fukushima Dai-ichi Nuclear Power Plant accident, surface water , dissolved cesium, groundwater in slope, forest headwater

This study was conducted in a forest headwater in Namie, Fukushima, which is a high deposition area, to investigate the factors that cause changes in dissolved Cs-137 in surface water. In the test watershed, surface water and groundwater were sampled and analyzed for dissolved Cs-137 concentration. We also conducted detailed hydrological observations. The results of this study showed the concentration of dissolved Cs-137 in surface water increased during rainfall. We also estimated the contribution to dissolved Cs-137 in surface water from radiocesium leaching of sedimentary litter and from Cs runoff by shallow groundwater. Future studies are needed to investigate the leaching test using litter and the time series of Cs concentrations in groundwater in the study watershed.