Mid- to long-term radiocesium wash-off from contaminated catchments at Chernobyl and Fukushima

Long-term prediction of $$^{137}$$Cs in Lake Onuma on Mt. Akagi after the Fukushima accident using fractional diffusion model

“…To be summarized, a combination of the exponential functions to describe Cs dynamics in a lake for initial/short-term phase and the power law (diffusional) approach for mid-, and long-term is the merit of the proposed fitting model. The disadvantage of the FDM is that the fitting parameters of the FDM are less related to physicochemical processes in a lake and their characteristics than the models of Smith et al 13 and Konoplev et al 18 , 19 .…”

“…Besides pure fitting, a parameter for a given lake and radionuclide in the diffusion model can be estimated using characteristics with clear meaning Cs deposition, effective diffusion coefficient, and distribution coefficient 11 , and thus predictions of Cs long-term dynamics in a lake can be provided immediately after the accident using previously measured values of the characteristics, literature data or expert judgments. Studies in the mid-, to long-term phases after the accident include models using sum of exponential functions 13 , 16 , 17 and process-level diffusion models 11 , 18 , 19 . The two-component decay function model (TDM) 16 , 17 , which is the sum of two exponential functions, was used to fit the measured Cs activity concentration and showed good agreement with the measured values 6 , 10 , 12 .…”

“…The two-component decay function model (TDM) 16 , 17 , which is the sum of two exponential functions, was used to fit the measured Cs activity concentration and showed good agreement with the measured values 6 , 10 , 12 . On the other hand, by using the diffusion models, Bulgakov et al 11 and Konoplev et al 18 , 19 succeeded in showing the temporal trend of radiocesium in the mid- and long-term phases after the accidents at Chernobyl and Fukushima.…”

Reconstruction of the Long-Term Dynamics of Particulate Concentrations and Solid–Liquid Distribution of Radiocesium in Three Severely Contaminated Water Bodies of the Chernobyl Exclusion Zone Based on Current Depth Distribution in Bottom Sediments

“…Long-term dynamics of 137 Cs concentrations in water bodies can be described using the earlier proposed semi-empirical diffusional model [44,45]. According to the model, for water bodies, where a major source of suspended material is the top layer of catchment soil, the long-term dynamics of 137 Cs particulate concentration c p and dissolved concentration c d can be described by the following equations:…”

“…The particulate 137 Cs concentration is determined by the effective dispersion coefficient D eff in the catchment topsoil, depending on 137 Cs speciation, sorption, and fixation ability of catchment soil, and climatic conditions (e.g., mean annual rainfall, mean annual air temperature, etc.) [31][32][33][34][35][36], whereas the dissolved 137 Cs concentration, along with D eff , is controlled by the distribution coefficient K d in the sediment-water system [3,45].…”