DEPLETED URANIUM (DU): ITS ENVIRONMENTAL DISPERSION AND HUMAN UPTAKE

Inhaled depleted uranium (DU) oxide aerosols are recognised as a distinct human health hazard and DU has been suggested to be responsible in part for illness in both military and civilian populations that may have been exposed. The issue has been the subject of investigations by the Royal Society (UK), the National Academy of Science (US), and other bodies but studies of individuals that were clearly exposed to environmental contamination are lacking. Our objective was to develop a high sensitivity method of DU detection in urine using MC-ICP-mass spectrometry that would be capable of detecting an individual′s historic ≥milligram-quantity aerosol exposure to DU up to 20 years after the event. We developed this method and applied it to individuals either known or likely to have had a DU aerosol inhalation exposure, and to a large voluntary cohort of 1991 Gulf conflict veterans (see www.DUOB.org) to assess DU-exposure screening reliability and accumulate data on exposure. Where exposure to DU aerosol has been unambiguous and in sufficient quantity, urinary excretion of DU can be detected more than 20 years later by our method, even when DU forms only ~1% of the total excreted uranium, and when U concentration is at the low end of the normal range (~1ppt U in urine). Most such samples would return a negative screening result with other, less sensitive methods. Our method has been used to show (1) that it is capable of resolving legal cases based upon a claim of DU exposure, (2) that the occurrence of DU in 1991 Gulf Conflict veterans is likely to be uncommon to rare, but (3) if a significant (i.e. mg-quantity) inhalation exposure occurred, that it can be detected in urine for decades to come. The method offers a way to resolve debates about DU and health and provide perspective on the issue. Resolving the potential implications of DU to health in contaminated populations is best done by properly testing exposed cohorts. The cohorts in need of study are those living in DU-contaminated areas of Iraq or those that have lived in the vicinity of DU munition factories with large DU contamination footprints.