# Presentation: 229002

## Depleted Uranium (DU) Follow-Up Program Update

**Depleted Uranium (DU) Follow-Up Program Update**

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

## 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%

- Leftover is “depleted” with 235U/238U isotopic ratio = 0.245%

- Depleted Uranium (DU)

## Isotopic Comparison of Natural and Depleted Uranium

** **

**Radioactivity**

** **

**Natural**

** **

**Uranium**

** **

**Depleted **

**Uranium**

** **

**Isotope**

** **

- 

- Ci/g

**Concentration**

**of isotopes**

**Concentration**

**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**

** **

**Radioactivity**

** **

- 1

- 0.6

- *

## 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

## 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**

**Notes:**
Concern about the toxicity of DU began after the Gulf War in which the US usd DU munitions for the first time.  Due to DU’s high density, it is an excellent metal for used in tank armore and in aormor-piercing munitions.

Suring two friendly fir incidents, US soldiers were exposed to DU through the inhalaion of aerolisizce DU oxide and from DU fragments 

There were also expossure incidents when a munitions storage facility burned and possible when mlitary equiipment was cleaned upon rmoveal from battlefields to remove Duoxide dust.

## Chemical vs Radiological Toxicity

- Chemical toxicity
**U****234**** = U****235**** = U****238**
- Radiological toxicity
- Specific activity: **U****234**** >>> U****235 ****> U****238**
- Primary decay = alpha particles and 				gamma rays

**Notes:**
Decay - Primarily by alpha emission
              Also small amounts of gamma radiation

          Daughter products of primary importance:  Thorium 234 and 231
			Protactinium 234m

Specific activity related to half life
       U234 t1/2 = 2.4 x105
       U235 t1/2 = 7.1 x 108
       U238 t1/2 = 4.5 x 109

## 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

## Slide 8

## 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

## 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 |  |  |  |  |

## Mean Urine Uranium Values (1993-2007, N=77)

## Individual Participant’s with 4 or More Visits Mean uU with Minimum and Maximum uU Values (n=35)

## 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

## Health Surveillance Results from 2007 Visit

## Demographic Characteristics of the 2007 Participantsa Compared to All Participantsb 

## Urine Uranium Values from 2007 Cohort (n=35)

## 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

## 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          Lo>Hi  Marginal
- Triglycerides   lo>hi   Marked and outside
-                                      normal range

## Summary of Renal Effect Measures

## Proximal Tubule Markers – 2007 Cohort

## Summary of Renal Parameters 1994-2007

## Other Clinical Findings

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

## Summary of Genotoxicological Measures

## Summary of Differences in Genotoxicity Parameters across Evaluations

## 2nd Mission of the DU Follow-Up Program

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

## 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

## Comparison of Urine Uranium Values from DUP, GWI and OIF(as of 6/30/08)

## Results of OIF Urine Surveillance(as of 30 June 08)

***All were invited to enter the DU Follow-up Program. Two from OIF/OEF declined but may**
**be interested in future follow-up**

**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**

## 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