Transfer of 90Sr to rice plants after its acute deposition onto flooded paddy soils

Autor: Chang-Woo Lee, Han-Soo Lee, Dong-Kwon Keum, Geun-Sik Choi, Hyo-Kook Park, In Jun, Hee-Suk Kang, Yong-Ho Choi
Rok vydání: 2007
Předmět:
Zdroj: Journal of Environmental Radioactivity. 93:157-169
ISSN: 0265-931X
Popis: The transfer of 90 Sr to rice plants following its acute ground deposition was examined experimentally in a greenhouse. Lysimeters were flooded after being filled with the soil monoliths from 12 paddy fields. A solution of 90 Sr was applied to the standing water in the flooded lysimeters at the pre-transplanting stage or booting stage. Applied 90 Sr was mixed with the topsoil only after the pre-transplanting application (PTA). The transfer was quantified with the areal transfer factor (TF a , m 2 kg −1 -dry) defined as the ratio of the plant concentration to the initial ground deposition. In the PTA, the first-year TF a values in the 12 soils were in the range of 8.2 × 10 −3 –2.1 × 10 −2 and 1.7 × 10 −4 –3.6 × 10 −4 for the straws and hulled seeds, respectively. The TF a values from the booting-stage application (BSA) were higher than those from the PTA by a factor of up to four. The ratios of the seed TF a to the straw TF a were, on the whole, higher in the BSA. The 90 Sr TF a in the PTA was negatively correlated with the soil pH and, to a lesser degree, the exchangeable Ca content. In the second year, the TF a in the PTA reduced to 53–90% of that in the first year. A more significant reduction, in general, occurred in a sandier soil. Based on the four consecutive years' transfer data, an overall half-time of the 90 Sr TF a was estimated to be 2.2 years.
Databáze: OpenAIRE