The study of the combined effect of soil properties on the rate of diffusion of ~(60)Co

摘要

The direct estimation of the value of the diffusion component of mass transfer of pollutants in arable soil horizons is an important task of scientific and applied importance. The values of effective diffusion coefficients of Co-60 radionuclide (D-eff) in water-saturated samples of different soils with disturbed structure and the same initial bulk density were obtained during the laboratory experiment. Of particular interest is the assessment of the contribution of individual specific characteristics of soils that have undergone the gleying process to the regulation of (DeffCo)-Co-60. There was noted a significant variability of (DeffCo)-Co-60 for investigated soils due to different soil characteristics. To assess this, influence a statistical approach has been used, where edaphic factors representing the most important characteristics of the soils acted as independent variables (predictors), and the dependent (resulting) variable was (DeffCo)-Co-60. The contributions of each of the selected indicators of soils state (independent variables) in varying of (DeffCo)-Co-60 were also identified. During the experiments, there was revealed a particularly strong increase in the (DeffCo)-Co-60 for soils with a high Eh, sigma Fr.(0.01 mm) and decrease in the absolute value of the dependent variable with two predictors: pH(H2O) and P2O5mobile in conditions of excessive moisture. Based on the study of the dependence between the main physicochemical soil properties and the magnitude of effective diffusion coefficients ((DeffCo)-Co-60), the selected physicochemical characteristics of soils were ranked by the degree of influence on the value of the dependent variable: pH(H2O) Eh sigma Fr. P2O5mobile C-org. At the same time, the multiple linear regression analysis of the obtained data showed statistical significance for two independent predictors of the model (pH(H2O) and sigma Fr.(0.01 mm)). As a result, semi-partial determination coefficients responsible for the share of the total variation of the dependent variable due to the statistically significant corresponding independent variables (pH(H2O) and sigma Fr.(0.01 mm)) were calculated based on the data presented.