Depleted uranium contamination: its mobility in the environment and impacts on health

Urine samples being processed

NERC isotope geoscience facilities (formerly NIGL) developed a new method for the detection of depleted uranium (DU) munitions pollution and applied this to Gulf War veterans to quantify exposure to DU munitions. The impact of this research for the UK government is that DU exposure was limited, and none of the 466 Gulf War veterans tested had detectable DU, so harm to veterans was small.

The test was also applied to munitions factory workers and quantified exposure to DU in exposed individuals and environmental materials, even 25 years after exposure.

Background

Between 1997 and 2008, there was considerable concern that exposure of military personnel, and collateral exposure of civilians, to armour-penetrating DU munitions might contribute to illness of veterans (Gulf War Illness, cancer, birth defects, etc.) and have other harmful environmental effects.

In 2005, the UK Government appointed the Depleted Uranium Oversight Board (DUOB) to commission a study to both develop a high-sensitivity test and apply this to veterans to find out if DU exposure was widespread. The Ministry of Defence (MoD) also commissioned a joint NERC research programme on the environmental impacts. No such test was available at that time.

Development of the test

Analyses of 238U/235U isotope ratio from urine samples

The research began with the development of a reliable, high-sensitivity uranium (U) isotope test for urine, which then evolved by developing a rapid, reasonable precision soil U isotope test. Subsequent work progressed to the U-isotope analysis of single particles less than 1 μm in size, this being useful for both analysis of DU and other particles within the environment. This urine test remains the most sensitive in the world.

Testing Gulf War veterans

Scanning electron microscope images of depleted uranium oxide

Use of the test showed that none of 466 Gulf War veterans tested had detectable DU, allowing the UK government to conclude the study and be satisfied that significant exposure to veterans by DU could not be substantiated. This allowed the UK MoD to largely draw a line under this particular issue, and reduce future expenditure related to DU-related issues.

The method development prompted a follow-up testing study to a $20 million study at the Southwestern Medical Centre, University of Texas, to test for DU exposure in 160 putative US veterans suffering all the brain abnormality and physiological symptoms of Gulf War Illness to see if there is any connection.

Wider environmental and health impacts

Subsequent work showed that

  • where DU aerosols were significant around a DU manufacturing plant in New York, exposure to humans and the environment was significant and detectable even after 25 years since the inhalation exposure happened
  • DU pollution migrated very slowly in soil
  • DU is also incorporated into biological tissue (plants, animals, humans)

The work showed that particles arising from combustion of DU in the factory were fully oxidised and amongst the least soluble, explaining why the pollutant persists for decades in the environment and the human body.

None of these conclusions were known until this work was done. The research proved the conclusions of the US Agency of Toxic Substances and Disease Registry — which stated that the DU contamination legacy surrounding the New York manufacturing plant could not be quantified and that detection in humans after 20 years would be impossible — to be entirely incorrect.

The long-term health and environmental effects of chronic DU-inhalation or ingestion exposure are as yet unquantified. In 2011–12, the New York State Department of Health developed a similar test and is addressing the continuing health concerns in that area by carrying out a proper health study of DU-exposed individuals.

The US Congress Committee on Science and Technology sought testimony from Prof Randall Parrish on 12 March 2009 concerning these new developments in order to learn lessons about how to quantify exposure and document the DU pollution within the environment.

This work contributes to improving the evidence base for government decision-making concerning balancing the advantages of munitions deployment against the harmful environmental and health effects.

Contact

Publications

Lloyd, N S, Chenery, S R, and Parrish, R R.  2009.  The distribution of depleted uranium contamination in Colonie, NY, USA.  Science of the Total Environment, 408(2): 397–407.

Lloyd, N S, Mosselmans, J F W, Parrish, R R, Chenery, S R, Hainsworth, S V, and Kemp, S J.  2009.  The morphologies and compositions of depleted uranium particles from an environmental case-study.  Min. Magazine, 73 (3), 493–508.

Lloyd, N S, Parrish, R R, Horstwood, M S A, Chenery, S R N.  2009.  Precise and accurate isotopic analysis of microscopic uranium-oxide grains using LA-MC-ICP-MS.  J. Anal. At. Spectrom., 24, 752–758 DOI: 10.1039/b819373h

Parrish, R R.  2007.  War veterans test negative for depleted uranium.  Planet Earth, pp. 9.

Parrish, R R.  2007.  Weapons factory workers and nearby workers exposed to depleted uranium.  Planet Earth, pp. 8–9.

Parrish, R R, Thirlwall, M, Pickford, C, Horstwood, M S A, Gerdes, A, Anderson, J, and Coggan, D.  2006.  Determination of 238U/235U, 236U/238U and uranium concentration in urine using SF-ICPMS and MC-ICP-MS: An inter-laboratory comparison.  Health Physics, 90 (2), 127–138.

Parrish, R R, Horstwood, M S A, Arneson, J, Chenery, S, Brewer, T, Lloyd, N, and Carpenter, D.  2008.  Depleted uranium contamination by inhalation exposure and its detection after c. 20 years: implications for human health assessment.  Science of the Total Environment, 390, 58–68; doi:10.1016/j.scitotenv.2007.09.044.