Comparison of 0.1 M Stable CsCl and 1 M NH₄NO₃ as an Extraction Reagent to Evaluate Cs-137 Mobility in Soils

To evaluate the mobility and bioavailability of ¹³⁷Cs in soils, we compared the extraction of ¹³⁷Cs with stable Cs and ammonium solutions from ¹³⁷Cs-contaminated minerals and soils. The extraction yields of ¹³⁷Cs with stable Cs were significantly lower than those with ammonium for minerals with frayed edge sites, but such differences were not observed for minerals without frayed edge sites. The amount of ¹³⁷Cs extracted with stable Cs from soils was lower than, or equal to, that extracted with ammonium. The above results suggest that stable Cs extracted the ¹³⁷Cs from easily accessible sites. Plant available ¹³⁷Cs was assessed using Kochia (Bassia scoparia) cultivated in pots of contaminated soils, and compared with soil parameters including extractable ¹³⁷Cs and K, and radiocesium intercept potential. The ¹³⁷Cs/K ratio extracted with stable Cs solution was found to be a potential index for evaluation of the easily mobile and bioavailable fraction of ¹³⁷Cs in soil.