Uranium Bioavailability and Environmental Risk Assessment in Soils Contaminated by Mining

The bioavailability, mobility and retention behaviour of uranium (U) in soils and mine wastes were investigated by a chemical extraction procedure. Based on these results, a risk assessment code was applied with the purpose to estimate the environmental risk associated with U. This code is based on the retention capacity of the chemical elements by different geochemical fractions in soils, thus identifying their toxicity, mobility and degree of availability to the environment and to living beings (ratio of the water-soluble fraction and exchangeable fraction to the total concentration). Uranium and many other elements (e.g., As, Bi, Cu, Sn, W) were found in high total concentrations, however the risk assessment code indicates a potentially hazardous situation in the mine site only for U pollution.