Horizontal and Vertical Transport of Uranium in an Arid Weapon-Tested Ecosystem br

Armor-penetrating projectiles and fragments of depleteduranium (DU) have been deposited in soils at weapon-tested sites. Soilsamples from these military facilities were analyzed by inductively coupledplasma-optical emission spectroscopy and X-ray diffraction to determineU concentrations and transport across an arid ecosystem. Under aridconditions, both vertical transport driven by evaporation (upward) andleaching (downward) and horizontal transport of U driven by surfacerunoffin the summer were observed. Upward vertical transport wassimulated and confirmed under laboratory-controlled conditions, to beleading to the surface due to capillary action via evaporation duringalternating wetting and drying conditions. In thefield, the 92.8% of Ufrom DU penetrators and fragments remained in the top 5 cm of soil and decreased to background concentrations in less than 20cm. In locations prone to high amounts of water runoff, U concentrations were reduced significantly after 20 m from the source dueto high surface runoff. Uranium was also transported throughout the ecosystem via plant uptake and wild animal consumptionbetween trophic levels, but with limited accumulation in edible portions in plants and animals.