Temporal changes in partitioning of ¹⁴C derived from acetic acid among solid, liquid and gas

Partitioning ratios of ¹⁴C among solid, liquid, and gas were determined by batch sorption tests using 6 Japanese paddy soil samples. The soil samples were classified as kuroboku soil, lowland paddy soil, grey lowland soil and gray lowland soil. Each of the soil samples was suspended in deionized water containing [1,2-¹⁴C] sodium acetate and shake-incubated for 10 days. The partitioning ratios were determined every day until the end of incubation. Temporal changes in partitioning of ¹⁴C were similar for all soil samples although the soil types were different among the soil samples. The ¹⁴C in liquid phase at the beginning of incubation was rapidly partitioned into solid and gas phase. From day 2 to the end of incubation, the partitioning ratios of ¹⁴C for the solid phase gradually decreased, and those for the gas phase were increased. Because the partitioning ratios for liquid phase were constant after day 2 of incubation, the increase in the partitioning ratios for gas phase were caused by the emission of ¹⁴C from solid phase. It is expected that these basic data may be used for construction of a dynamic compartment model which predicts the behavior of ¹⁴C in paddy fields. (author)