The distribution of Cs-137, K, Rb and Cs in plants in a Sphagnum-dominated peatland in eastern central Sweden

We record the distribution of 137Cs, K, Rb and Cs within individual Sphagnum plants (down to 20 cm depth) as well as 137Cs in vascular plants growing on a peatland in eastern central Sweden. In Calluna vulgaris 137Cs was mainly located within the green parts, whereas Andromeda polifolia, Eriophorum vaginatum and Vaccinium oxycoccos showed higher 137Cs activity in roots. Carex rostrata and Menyanthes trifoliata showed variable distribution of 137Cs within the plants. The patterns of 137Cs activity concentration distribution as well as K, Rb and Cs concentrations within individual Sphagnum plants were rather similar and were usually highest in the capitula and/or in the subapical segments and lowest in the lower dead segments, which suggests continuous relocation of those elements to the actively growing apical part. The 137Cs and K showed relatively weak correlations, especially in capitula and living green segments (0–10 cm) of the plant (r ¼ 0.50). The strongest correlations were revealed between 137Cs and Rb (r¼ 0.89), and between 137Cs and stable Cs (r ¼ 0.84). This suggests similarities between 137Cs and Rb in uptake and relocation within the Sphagnum, but that 137Cs differs from K