陸水系における¹³⁷Csの放射生態に関する研究

―沼底土壌における¹³⁷Csの結合形態別分析―

抄録

In order to investigate in more detail on the¹³⁷Csconcentration in pond sediments, we have carried out analysis on the bonding forms of¹³⁷Csin pond sediments. The existing rate of different bonding forms of¹³⁷Csin pond sediments was found to be below 5% for F1: exchangeable and F2: bound to carbonates, 18-24% for F3: bound to iron and manganese oxides, 14-17% for F4: bound to organic matter and 54-60% for F5: residual (mainly, bound to silicate minerals) . Furthermore, we have investigated the relations among the¹³⁷Csconcentration in each place, the ignition loss, the total carbon and the cation exchange capacity of pond sediment, respectively. We have found a tendency that the larger the ignition loss, the total carbon and the cation exchange capacity are, the higher the¹³⁷Csconcentration is. On the other hand, about 90% of⁴⁰Kin pond sediments is in the form of F5, and the bonding forms of¹³⁷Csand⁴⁰Kare obviously different regardless of the fact that both are alkaline metals.