HEALTH EFFECTS OF UNIQUE METAL EXPOSURES: DEPLETED URANIUM (DU) EMBEDDED FRAGMENTS IN GULF WAR I VETERANS

Chronic exposure to metals is most often determined by the geology of the area in which people reside; however there are exceptions that include people’s occupational exposures and military combat experiences that result in retained embedded metal fragments. The potential that systemic exposure to metals released from embedded fragments can be sufficiently high to cause health problems in individuals was first tested in a cohort of 1991 Gulf War I U.S. soldiers accidently exposed to depleted uranium (DU) when their DU-armored tanks were hit by DU penetrators during friendly fire incidents. DU is a by-product of the U enrichment process during which two isotopes of U (U²³⁴ and U²³⁵) are removed from natural U, leaving DU with an isotopic ratio of U²³⁵/U²³⁸ = 0.0020 compared to natural U’s isotopic ratio of 0.0074. Isotopic analysis of U in urine and blood was used to confirm that the source of elevated U in urine and blood samples was from embedded DU fragments. A biennial health surveillance program established for these soldiers in 1993 by the Department of Veterans Affairs (VA) has shown a sustained (> 20 yr) elevation of urine and blood U concentrations in members of the cohort with DU embedded fragments. To date no clinically significant DU-related health effects have been observed in this population, however biomarkers targeting renal proximal tubule cell function and damage have shown some evidence of renal effects when results are compared between high vs low urine U exposure groups. Continued biomonitoring of this group is recommended due to the on-going systemic exposure to DU in Veterans with DU embedded fragments. Supported by the Department of Veterans Affairs and approved by the Baltimore VA Medical Center’s Office of Research and Development and University of Maryland’s School of Medicine Institutional Review Board.