Relationships between Paddy Soil Radiocesium Interception Potentials and Physicochemical Properties in Fukushima, Japan

The radiocesium interception potential (RIP) of bulk soil (RIPsoil) can reliably be used to predict the magnitude of soil-to-plant radiocesium transfer. There has been some controversy about which soil properties control the RIPsoil, although the RIP is theoretically proportional to the amount of frayed edge sites in micaceous clay minerals. The RIPsoil was determined for 97 paddy soils in three regions (Hama-dori, Naka-dori, and Aizu) in Fukushima Prefecture, Japan, and the relationships between selected physicochemical properties and the RIP were analyzed. The mean (+/- standard deviation) of the RIPsoil for the 97 soils was 1.67 (+/- 0.87) mol kg(-1), and the range was 0.34 to 5.36 mol kg(-1). Pearson correlation analysis revealed that the RIPsoil positively correlated best (P < 0.01) with the clay fraction K content as a mass fraction of the bulk soil (clay-K-soil) and negatively correlated with the total C content and the phosphate absorption coefficient (P < 0.05). Therefore, clay-K-soil, an indicator of the amount of micaceous clay minerals in a soil, was confirmed as being useful for estimating the magnitude of the RIPsoil for paddy soils in Fukushima. The RIPsoil was invariably low if either the total C content exceeded 6.0% or the phosphate absorption coefficient exceeded 1500 mg kg(-1), suggesting that these parameters could be useful for screening soils with particularly low RIPsoil values.