The Effects of Different Uranium Concentrations on Soil Microbial Populations and Enzymatic Activities

Uranium is an ubiquitous constituent of natural environment with an average concentration of 4mg/kg in earth crust. However, in local areas it may exceed the normal concentration due to human activities resulting in radionuclide contamination in groundwater and surface soil. The effect of six levels of uranium concentration (0, 50, 100, 250, 500 and 1000mg kg-1) on soil phosphatase activities and microbial populations were studied in a completely randomized design as a factorial experiment with three replications. The results showed a significant decrease in phosphatase activity. The result of the experiment suggests that soil microbial populations (bacteria, funji and actinomysetes) decrease by increasing the uranium levels in the soil. Therefore, assessment of soil enzymatic activities and microbial populations can be helpful as a useful index for a better management of uranium and radioactive contaminated soils.