Short- and Long-Term Behavior of Depleted Uranium In the Environment of Southern Region of Iraq

摘要

The Iraqi environment had been extensively exposed to depleted uranium (DU) contamination in the course of military operation in 1991 and 2003. Burning of tanks and armored vehicles led to the formation of large quantities of fine aerosol containing predominantly poorly soluble uranium oxides. The DU aerosol is deposited on soil surface, transported far from the vicinity of the target, or resuspended in the air by the wind action. Therefore, data from within the country on the behavior of DU in the environment are essential and would offer first-hand basis on many topics of the impact of DU contamination on the environment and health. In the 1st part of the study nearly ten years after military operation, transport of DU from contaminated soil of the southern region of Iraq had been investigated in undisturbed soil columns taken from four locations of battlefield at Basra Governorate. In the 2nd part of the study, uptake of DU was assessed in a field experiment utilizing tomatoes. The plots were mixed with a contaminated soil and the recommended agricultural practices were used during the growing season. At the end of season, samples of the aboveground and belowground were digested and analyzed for their content of DU. Samples of soil, effluent, and plant were analyzed for DU using Solid Scintillation and Liquid Scintillation Counters. Results indicated that no DU had been detected in the eluted samples even after heavy leaching with a variety of displacing solutions. At the same time, no DU had been migrated from soil to above- and below-ground parts of the tomatoe plants. These data suggest that the DU occurred in soil as metal or oxides remains as insoluble forms even after ten years of weathering under desert conditions. It is expected therefore, that the wind action is the main mechanism dominated the transport of DU in the environment of southern region of Iraq.