Partitioning of ¹⁴C into Solid, Liquid, and Gas Phases in Various Paddy Soils in Japan

Abstract

The partitioning ratios of ¹⁴C in solid, liquid, and gas phases were determined by batch sorption tests using 97 paddy soil samples. Each of the soil samples was suspended in deionized water containing [1, 2-¹⁴C] sodium acetate and shake-incubated for 7 days. More than 65% of the spiked ¹⁴C was released into the air, approximately 30% was partitioned into the solid phase, and the ¹⁴C remaining in the liquid phase was only a few percent. These results suggested that if the ¹⁴C incorporated into acetate migrated from a TRU repository site to paddy fields, most of the 14C would be released into the air and the rest would be partitioned into the soil phase. It is likely that microorganisms in the soils are responsible for these partitioning ratios because about 97% of the spiked ¹⁴C remained in the liquid phase in the microorganism-depleted sample.

KEYWORDS:

• TRU waste
• ¹⁴C
• partitioning ratio
• safety assessment