Influence of Soil Type and Physical–Chemical Properties on Uranium Sorption and Bioavailability

Abstract

This work was undertaken to study the influence of soil type and its physical and chemical properties on uranium sorption and bioavailability, in order to reduce the uncertainty associated with this parameter in risk assessment models and safe food production. The tests were conducted on three types of Serbian soils: alluvium, chernozem, and gajnjaca, from which 67 samples were taken. Dominant factors of uranium mobilisation: the specific content of total/ available form of uranium and phosphorus, the degree of acidity (pH KCl ), and humus content and their correlation, were analysed. Content of available uranium form, according to the type of soil decreases in the following order: gajnjaca>alluvium>chernozem. It was found the medium correlation between pH values and available content of uranium in chernozem and gajnjaca, statistically significant at the level of significance of 99% and the alluvium at the level of significance of 95%. Correlation coefficients in all cases were negative, indicating that the reduction in pH increases the mobility of uranium and thus its availability for the adoption of the plants. Soil pH was the only dominant factor that significantly controlled the uranium value with no further significant contribution of other soil parameters.

Internal dose assessment of 238U contaminated soils based on in-vitro gastrointestinal protocol

“…In general, alluvium soil has medium humus content. Based on research done by Stojanovic et al [23], there was some significant correlation and dependence among the total uranium content and humus content. Humus consist of decomposed organic material that has a characteristic to form uranyl ions strong complexes when participate in the fixation of uranium in the soil.…”

Chemometric approach for prediction of uranium pathways in the soil

“…forming low soluble uranyl phosphates or precipitation products such as autunite ( p = 10 −49 ), that are stable over a wide range of geochemical conditions [5]. Precisely this trait of uranium(VI)-phosphate interactions utilize remediation methods for uranium contaminated sites, mainly based on phosphorus application.…”

“…Available uranium (U av ) fraction was determined by extracting 10 g of soil sample with 50 cm 3 of AcNH 4 solution for a period of 2 h (AcNH 4 solution: 77 g of CH 3 COONH 4 and 50 cm 3 of glacial acetic acid in 1000 cm 3 distilled water, pH-4.8) [5,41,42]. Extracted uranium was determined in the same way as total uranium.…”

“…Phosphorus fertilizers are the main anthropogenic source of uranium in the environment (about 73% of the total uranium input) [5]. Technological methods of processing phosphate ore to obtain fertilizer are such that 85%-90% of total uranium content is being moved into the final product [5][6][7][8][9][10][11].…”

“…Technological methods of processing phosphate ore to obtain fertilizer are such that 85%-90% of total uranium content is being moved into the final product [5][6][7][8][9][10][11]. Solubility of uranium in the soil depends on the environmental pH, redox potential, soil structure and mineral composition of the solid phase, concentration of inorganic compounds, the quantity and type of organic compounds in the soil and soil solution, temperature, pressure, moisture content and microbial activities [2,3,5,9,[12][13][14][15]. Echevarria et al [16], emphasize that the soil pH value is the predominant factor which determines the uranium mobility.…”