EAPSI: Radioactive Cesium Level in the Environment and its Interaction with Post-Disaster Land Management--A case study of Fukushima, Japan

The nuclear plant accident following the strong earthquake and tsunami in Fukushima, Japan in 2011 released radioactive cesium into the atmosphere which then accumulated in the soil. Radioactive cesium can be transferred from soils to humans through the food web, with the potential of causing health hazards. Recovery from such an accident requires long-term monitoring and appropriate land management. Unfortunately, rushed decisions following a disaster often do not fully consider the environmental processes and fail to mitigate the contamination, or, even worse, leave a long lasting negative impact on the environment. This research examines changes in cesium levels in soils in Fukushima as well as the effects of land management on cesium levels. The research will be conducted under the mentorship Japanese experts in the agriculture and environmental engineering fields, Dr. Taku Nishimura at the University of Tokyo and Dr. Kazutoshi Osawa at Utsunomiya University.<br/><br/>The size of the cesium ion (Cs+) is similar to the size of the potassium ion (K+) and the ammonium ion (NH4+) which are commonly applied as agricultural nutrients and could be exchanged with Cs+ in clay structure. The radiation levels of collected soil samples in Fukushima will be measured by a germanium semiconductor detector. The results will be compared with the prior readings to determine the change rate. Cs+ adsorbed in soils can be translocated, exposed to the air, or leached by soil erosion and land management practices. Soil erosion rates in the area will be determined by GeoWEPP, a soil erosion modeling software. Land management practices, which were implemented following the accident, will be reviewed based on the data obtained from local governments. The field data and the land management data will be loaded into GIS software and the best practice for chemical hazard mitigation will be modeled.<br/><br/>This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the Japan Society for the Promotion of Science.