Depleted Uranium (DU) Follow-Up Program Update

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Depleted Uranium (DU) Follow-Up Program Update

• Melissa A. McDiarmid, MD, MPH, DABT
• VA Maryland Health Care System
• University of Maryland
• Baltimore, USA

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Depleted Uranium (DU)

• By-product of uranium enrichment process through
  which 235U is extracted from natural uranium for
  use as nuclear fuel
• Leftover is depleted with 235U/238U isotopic
  ratio 0.245

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Isotopic Comparison of Natural and Depleted
Uranium


Natural

Depleted
Radioactivity

Uranium

Uranium

Concentration

Concentration

Isotope

m
Ci/g

of isotopes

of isotopes

234
U

6200.0

0.0058

0.001


235
U

2.2

0.72

0.2

238
U

0.33

99.28

99.
8

Relative


1

0.6


Radioactivity

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Military Uses of DU

• Tank armor for increased resistance to enemy
  projectiles
• Munitions to increase penetrating power
• Used in battle for first
• time in 1991 Gulf War

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Gulf War Exposures to DU

• Friendly-fire incidents exposed US soldiers to
• DU shrapnel
• Aerosolized DU oxides
• Inhalation, ingestion, wound contamination
• Burning of munitions storage facility
• Decontamination of military equipment

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Chemical vs Radiological Toxicity

• Chemical toxicity
• U234 U235 U238
• Radiological toxicity
• Specific activity U234 gtgtgt U235 gt U238
• Primary decay alpha particles and gamma rays

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Purpose of DU Friendly Fire Victim Surveillance
Program

• Determine DU-related health effects, if any, in
  exposed soldiers
• Develop methods to measure uranium exposure
• Inhalation exposure/wound contamination
• Embedded fragment
• Examine surgical management of fragments

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Measurements of DU Exposure

• Urine uranium concentrations
• Relation between fragment status and elevated
  urinary uranium levels first observed in 1994
  visit
• Confirmed in all 6 subsequent visits
• Developed analytical method for measuring DU vs
  total U
• U235/U238 isotopic analysis

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Summary of Surveillance Visits
Gulf War OIF
Year DU-exposed Non-exposed DU-exposed Total
1993-4 33 33
1997 29 38 67
1999 21 29 new 50
2001 31 8 new 39
2003 32 4 new 32
2005 30 3 37
2007 32 3 new 2 (1 new) 37
77 unique cases have been evaluated from Gulf War I 4 unique cases have been evaluated from OIF 77 unique cases have been evaluated from Gulf War I 4 unique cases have been evaluated from OIF 77 unique cases have been evaluated from Gulf War I 4 unique cases have been evaluated from OIF 77 unique cases have been evaluated from Gulf War I 4 unique cases have been evaluated from OIF 77 unique cases have been evaluated from Gulf War I 4 unique cases have been evaluated from OIF
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Mean Urine Uranium Values (1993-2007, N77)
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Individual Participants with 4 or More Visits
Mean uU with Minimum and Maximum uU Values (n35)
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Radiation Dose Estimate from Whole Body Counting

• Nine veterans with whole body measurements above
  background
• Radiation dose estimates calculated using ICRP 30
  Biokinetic model for U
• 0.01 to 0.11 rem/year
• 0.61 to 5.33 rem/50 years
• Public dose limit 0.1 rem/year
• Occupational limit 5 rem/year

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Health Surveillance Results from 2007 Visit
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Demographic Characteristics of the 2007
Participantsa Compared to All Participantsb
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Urine Uranium Values from 2007 Cohort (n35)
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Health Surveillance Protocol

• Complete history (medical, social, family,
  reproductive, occupational exposure, partner)
• Extensive laboratory studies (hematology, serum
  chemistry, neuroendocrine, urinalysis, urine,
  semen and blood uranium, renal markers, semen
  analysis, bone metabolism)
• Chromosomal analysis (HPRT, chromosomal
  aberrations)
• Neurocognitive testing
• Focus group/risk communication

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Clinical Findings 2007 Visit

• Hematology parameters
• No statistically significant differences observed
  between Hi and Lo Uranium groups
• All results were within normal limits
• Chemistry results
• No statistically significant differences except
  for
• Bilirubin LogtHi Marginal
• Triglycerides logthi Marked and outside
• normal range

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Summary of Renal Effect Measures
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Proximal Tubule Markers 2007 Cohort
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Summary of Renal Parameters 1994-2007
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Other Clinical Findings

• No clinically significant differences detected
  between low and high uranium exposure groups for
• Semen characteristics
• Neuroendocrine measures
• Neurocognitive measures

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Summary of Genotoxicological Measures
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Summary of Differences in Genotoxicity Parameters
across Evaluations
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2nd Mission of the DU Follow-Up Program

• Since 1998
• To provide biologic monitoring by mail for
  uranium for all GWI and OIF veterans

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Purpose of the Urine Biomonitoring Program

• Determine urine uranium concentration in veterans
  from GWI and forward
• Passively survey for exposure scenarios linked to
  DU exposure other than friendly fire
• Provide assistance to veterans primary care
  providers in interpreting results and answering
  veterans questions

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Comparison of Urine Uranium Values from DUP, GWI
and OIF(as of 6/30/08)
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Results of OIF Urine Surveillance(as of 30 June
08)
Samples processed 2229
Gulf War I
OIF/OEF
Isotopic signature for natural uranium 394
Isotopic signature for natural uranium 1362
Isotopic signature for DU 1
Isotopic signature for DU 3
Isotopic analysis not done 469
All were invited to enter the DU Follow-up
Program. Two from OIF/OEF declined but may be
interested in future follow-up
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Summary

• Subtle health effects observed in DU exposed
  veterans are most likely the result of chemical
  effects of U
• Decreased reabsorption of filtered proteins in
  renal proximal tubules
• Subtle changes in bone metabolism
• Weak genotoxicity results are consistent with epi
  studies examining carcinogenicity in U millers
  and miners
• Mechanisms of DU genotoxicity may be a mix of
  chemical and radiologic effects
• Potential for foreign body reaction in vicinity
  of embedded fragments is a concern