“…Several hundred tons of DU were released in military conflicts over the past forty years and DU was expected to remain in battlefields and army testing sites [3] , [4] , [5] , [6] , [7] . We previously reported that significant U was accumulated in army weapon test sites – Yuma Proving Ground site [5] , [6] , [7] . In the fields of Yuma Proving Ground, 92.8% of U from DU penetrators and fragments remained in the top 5 cm of soil and decreased to background concentrations in less than 20 cm [7] .…”