摘要：In the present study we assessed the radiocaesium uptake by plants in order to piece together information on factors affecting the uptake processes, particularly K supply and plant species differences. Vegetation uptake from soil contaminated by the Chernobyl accident was compared at two semi-natural grasslands. The Cs/K discrimination factor (DF), which is often used to evaluate a plant's efficiency in absorbing nutrients from soil, was estimated. The obtained DF values (0.01 to 0.8) vary with K soil concentrations and plant species, indicating that the 40 K is more efficiently absorbed than 137 Cs. The soil-to-plant relationship was evaluated by means of the transfer factor (TF). The 137 Cs TF sp values obtained from separated plant species varied within the range of 0.016 to 0.400 (site 1) and 0.017 to 0.171 (site 2). When mixed grass samples were considered a large variation was observed, mainly for site 1. The 137 Cs TF mix ranges were: 0.018 to 0.250 for site 1 and 0.017 to 0.167 for site 2. These values fall within the range of TFs commonly reported (0.0001-1). Our present data suggest that these pastures are apt for forage use. Different plant species presented different individual behavior regarding their 137 Cs TF sp when the 40 K soil activity concentration was taken in account. For most of the species analyzed, we observed a gradual decrease in the individual 137 Cs TF sp when the 40 K soil activity concentration was increased, with the exception of Taraxacum officinale at one of the sampling sites.
关键词：Soil-to-plant relationship; Transfer factor; Radiocaesium; Radiopotassium
