Depleted Uranium Exposure Myths, Facts, and What You Need to Know to Talk to Your Patients.
Omowunmi (‘Wunmi) Osinubi, MD, M.Sc., MBA, FRCA.
Adjunct Assistant Professor Department of Occupational and Environmental Health UMDNJ-School of Public Health & Robert Wood Johnson Medical School
Occupational Health Physician War Related Illness and Injury Study Center
Depleted Uranium - Clinical Case
Mr. Just Strong is a 39 yr old OIF Veteran
Recently diagnosed with Hodgkin‟s lymphoma His new born baby that was conceived post-deployment has down syndrome
As Samawah, Iraq from 2/2003 to 8/2003 Al Asad, Iraq from 8/2004 to 4/2005
Smoke from burn pit Sand and dust storms Spider bites Multiple immunizations including small pox & anthrax Depleted uranium
As Samawah base was reportedly contaminated with gamma radiation & DU.
550,000 metric tons of yellow cake uranium was reportedly transported through Baghdad which had to be transported by rail. The only major rail line was through As Samawah.
Locals looted containers of uranium from the Tuwaitha nuclear complex, Used the large plastic containers as drinking pots, building materials, e.t.c.
Area littered with remnants/residues DU munitions & damaged vehicles Area was found to have radiation levels that were 300X the background rate. His colleagues had non-specific rashes, joint aches, lethargy and malaise, but he had no symptoms at the time. He was situated in close proximity to the 442nd US Military Police Brigade and members of this unit reportedly have had a number of health problems. http://www.msnbc.msn.com/id/25546334/
Public Perception - Toxic Effects of DU
Doctor: Did depleted uranium cause my health problems/concerns?
“The term depleted uranium is linguistically radioactive. Simply uttering the words can prompt a reaction akin to preaching atheism at tent revival. Heads shake, eyes roll, opinions are yelled from all sides”
- Deborah Hastings
Heaviest naturally occurring element
19 X that of water 1.65 X that of lead
Soil, rocks, surface & underground water, air, plants & animals
0.0003% of earth crust 3.0 µg/L in sea water
Trace amounts in food & water
1-2 µg daily intake in food 1.5 µg/L of water consumed
Human body content
Average 90 µg
69 µg in skeleton 7 µg in kidneys
Appearance: silvery gray metallic Corrodes to a spalling black oxide coat in air
Civilian Uses of Natural Uranium
Primarily used as fuel for nuclear power plants
Smaller amounts used in manufacturing
Ceramic & pottery glazes Yellow glass Light bulbs & filaments Photographic chemicals Dentures Leather & wood stains/dyes
Radioactive Properties of Natural Uranium
Weakly radioactive element with 3 isotopes
highest abundance; lowest radioactivity T ½ = 4.46 billion years
235 U (0.7200%)
T ½ = 704 million years
234 U (0.0055%)
lowest abundance; contributes half of radioactivity of natural uranium T ½ = 245,000 years
Uranium isotopes primarily emit alpha particles
α particles are large & heavy with little penetrating power Range is 4 cm in air Travels only 25-80 µm in tissues Poses radiation hazard only if it is in the body
Uranium isotopes decay to other radioactive elements which eventually decay to stable isotopes of lead
Decay process emits beta particles & gamma rays
Beta high energy electron range
15 m in air 1 cm in solids
Highly penetrating ionizing radiation Radiation hazard even when outside the body. An induced nuclear fission event involving uranium-235
What is Depleted Uranium?
DU is a byproduct of a process that converts natural uranium to enriched uranium for use in nuclear weapons and reactors
What is left is “depleted” uranium
DU is partially depleted of 235U & 234U
Ratio of 238U to 235U
Natural uranium = 137.88 Depleted uranium = 314.95
DU is about 60% as radioactive as natural uranium
Physical Properties of DU
Extremely dense heavy metal
1.67 times as dense as lead Only slightly less dense than tungsten and gold 84% as dense as Osmium or iridium (densest known substances)
High melting point
2070oF or 1132oC
High tensile strength
Comparable with that of most steel
Abundant and inexpensive
DU Commercial Uses
Radiation shielding in medical equipment Aircraft counterweights Rotors Flywheels Ship ballasts Gyroscopes
Military Uses of DU
The M2/3 Bradley fighting vehicles, M1-series tanks, and some US military aircrafts fire DU munitions
25mm & 30mm DU rounds fired by the Air Force‟s A10 aircraft & Marine Corps‟ AV-8B Harriers 105 mm & 120 mm kinetic energy penetrators anti-armor rounds fired by the Abrams tanks US Navy‟s Phalanx CIWS's M61 Vulcan Gatling gun used 20 mm armor-piercing penetrator rounds
The M1A1/A2 Abrams heavy armor tanks use steel-encased DU for increased armor protection.
DU and Military Applications
Exceptionally valuable for use in weaponry for offense
Armor-piercing DU penetrating munitions
For a given mass of DU, it has a smaller diameter than an equivalent lead projectile Less aerodynamic drag Deeper penetration due to a higher pressure at impact
DU – Effective for Offence
DU rounds burst into flames when they hit their targets Frequently causes explosions and fires especially when the target‟s fuel tank or munitions are ignited
DU – Effective for Defense
High density DU is sandwiched between sheets of steel armor plate
Location of DU armor
M1A1HA & M1A2 Abrams tanks built after 1998 have DU reinforcement in armor plating in the front of the hull and the turret.
Use of Depleted Uranium in War
US Army began researching the use of DU for military applications in the early 1970s
The Persian Gulf War (PGW, 1990-91) was the first time that US military used DU munitions & armor protection extensively during conflict
Estimated 320 tons of DU was used in PGW US military fired an estimated 860,000 DU rounds, many in training & practice
Thousands of Iraqi tanks were destroyed by DU munitions None of the American DU armored tanks were penetrated by Iraqi fire
Use of DU in Other US Conflicts
10,800 DU rounds were fired
30,000 DU rounds were fired
Operation Iraqi Freedom & Operation Enduring Freedom (2003 to Present)
Estimated amount of DU???
DU Exposures of Military Personnel
Iraqi forces did not have DU weaponry US military personnel were exposed to DU as a result of:
Friendly-fire incidents Clean-up and salvage operations Close proximity to burning DU armored tanks Occupants of Army combat vehicles struck by DU projectiles
Camp Doha, Kuwait fire PGW - July 1991
A defective heater in an M992 ammunition carrier loaded with 155 mm artillery shells caught on fire and exploded
Fire spread to other stored munitions and other vehicles loaded with ammunition
Chaotic series of explosions and fires, with vehicles & shells exploding for over 6 hours & fire burning for 24 hours
Fire destroyed $15 million in ammunition, over 100 vehicles and more than 20 buildings
Troops at the scene & clean-up personnel may have been exposed to DU residue
4,000 people in the area 600 directly involved in cleanup & decontamination
Others were likely exposed through contact with vehicles or inhalation of DU dusts
Camp Doha Fire
DU Exposure Assessment
Routes of exposure DU penetrator strikes on military tanks/vehicles generate inhalable aerosols with high concentrations of DU DU fragments can cause deep penetrating shrapnel wounds that may be retained in tissues Ingestion of DU particles in contaminated vehicle and/or dusts is possible, but unlikely to be an important exposure route
DU Exposure Assessment (contd.)
Exposure to DU aerosols affected by:
Characteristic of struck vehicle and impact conditions
Soft target (e.g., lightly armored vehicle)
Little conversion to DU oxides
Hard target (e.g., Abrams tank), much of penetrator mass is converted to DU oxides Substantial DU aerosols generated
Residence time of personnel in contaminated vehicle
(DOD office of the Special Assistant for Gulf War Illness)
Level I – highest exposures
Occupants in or near combat vehicles when they were struck by DU rounds Occupants of DU armored vehicles struck by non-DU munitions Soldiers entered the struck vehicle soon after impact Persons with DU fragments in shrapnel wounds
Inhalation of DU aerosols, ingestion of DU dusts and or contamination of open wounds with DU particles
Levels of exposure to DU
Approximately 164 individuals experienced Level I exposures from friendly fire incidents in PGW
Approximately 75 soldiers with level I exposure are in a DU health effects cohort study.
Levels of Exposure to DU
Level II – Intermediate exposures
Soldiers & civilian employees worked on DU contaminated vehicles Clean-up efforts from Camp Doha fire
Estimated 700 people
Level III – Lowest exposures
Troops downwind of burning DU ammunition or vehicles, or Camp Doha fire Personnel entered DU contaminated Iraqi tanks
Estimated number of people is unknown
Chemical Toxicity of DU
Enriched, natural and depleted uranium have identical chemical properties & tissue toxicity Kidney toxicity is primary effect of soluble uranium compounds
Studies of Uranium miners have documented impaired kidney function None have found excess mortality from renal disease
Lung injury potentially caused by ionizing radiation from uranium decay isotopes
Insoluble uranium compounds remain in pulmonary tissues especially lymph nodes for a long time and constitute localized radiologic hazard
Radiological effects of natural uranium exceed those of DU Studies of uranium miners & mill workers
High levels of uranium exposures over long periods Prior research suggested elevated rates of lung & laryngeal cancer, leukemia & other cancers Recent reviews & government reports have concluded that the apparent increased rates of cancers in uranium workers is questionable
Increased lung cancer attributable to confounding factors such as radon exposure in uranium mines, except at very high levels of U exposure.
Health Effects of DU Evidence-based Perspective
Report RAND, 1999 Key Findings Little concern related to radiological effects and cancer or other health outcomes. Evidence does not suggest long-term excess morbidity or mortality from hematological or renal changes. Inadequate evidence is to determine whether there is an association between uranium exposure and lung cancer or other cancers. Insufficient evidence to determine whether uranium exposure is associated with nonmalignant renal diseases, respiratory disease, or reproductive effects. In the Gulf War, Level I exposures may have exceeded radiation and chemical standards, warranting medical follow-up of individuals in friendly fire incidents; Levels II and III exposures are not likely to cause health effects.
IOM, 2000 & 2008
Health Effects of DU Evidence-based Perspective
Report World Health Organization 2001 British Royal Society 2002 Capstone Report 2004 Key Findings DU may produce transient dose-related effects on renal function; Insoluble inhaled particles may cause radiological damage in lung tissues, dermal effects are unlikely. Excess risk associated with radiation, primarily for lung cancer, is extremely small. Chemical toxicity may cause acute kidney effects in relation to very high exposure. Modeled health risks from DU inhalation, based on simulated friendly fire exposures, indicate that health effects from radiation are generally unlikely for personnel in, on, or near vehicles hit by DU munitions. Minimal increase in cancer risk and short-term kidney effects possible for personnel in unventilated Abrams tanks. Individuals working in DU contaminated vehicles for long periods may also exceed occupational exposure standards.
Cohort Study of PGW Veterans with Level I DU Exposure
Ongoing studies of Veterans who have embedded DU shrapnel compared to Veterans who had no exposure to DU.
After almost 14 years of follow up, the DU shrapnel group has not had any health problems that can be linked to the DU, including cancer, birth defects and kidney problems, even though their measures of uranium on a urine test are elevated, as expected.
Minor elevations in renal function tests did occur for the DU shrapnel Veterans but the overall mean values remained within normal clinical ranges. Future research is needed to investigate if these minor changes would impact kidney function later on in life. Current cohort has insufficient duration of follow-up and/or number of subjects to address cancer and or reproductive endpoints
Squibb et al. 2008, 2009; Squibb & McDiarmid, 2006; McDiarmid et al, 2004, 2001
Key Questions to ask to determine Veterans’ Probable DU Burden
Question (s) about Exposure Possible Exposure (s) Body Burden of DU
Did you have contact with intact DU?
Handling intact DU munitions or sitting inside or near a vehicle with intact DU armor.
The likelihood of exposure is extremely low and would approximate to Zero
Slight/mild exposure Quite unlikely that there will be significant body burden of DU
Did you fire DU munitions?
Loading and firing weapons that fire armor piercing ammunition made of DU. Some smoke/fumes may be present, especially in closed spaces (e.g., tanks).
Key Questions to ask to determine Veterans’ Probable DU Burden (Contd.)
Question (s) about Exposure Were you in close proximity to burning or exploded DU? Possible Exposure (s) Being in the smoke cloud of exploded DU munitions or burning DU armor, such as on an Abrams battle tank or a Bradley fighting vehicle. Body Burden of DU Mild to moderate chance of inhalation and/or ingestion of DU particles.
Do you have retained DU shrapnel in your body?
Metal fragments from DU armor or DU munitions remain in the body after an attack or accident.
High chance of significant DU in the body. These Veterans may need to be evaluated further for DU exposure.
Discuss Risks of DU Exposure with Veteran
Engage in meaningful dialogue with the vet about his/her DU exposure concerns
Allow the Veteran to completely state what his or her concerns are before attempting to provide the factual information.
Listen and Empathize Acknowledge and Normalize
Be honest and open with the Veteran about what you do and do not know
Builds trust and credibility
Provide factual information about DU Address any residual DU exposure concerns Offer test for DU if indicated
Probable moderate to high exposures Any level of exposure if Veteran remains concerned about DU
What is the ‘Test’ for DU and What does it Show?
Baltimore VA Medical Center (800-815-7533).
24-hour urine collection test measures the total uranium excretion rate (Gold standard). If the level of urine uranium is high, additional testing of the same urine sample will examine how much of the total uranium is DU. Compares individual‟s level of urinary DU to the normal range of DU excretion in the general population.
Results communicated directly to the Veteran by letter. A copy is sent to the referring VA provider.
If urinary DU is high, the Veteran may be enrolled in an ongoing program to follow the uranium excretion rate over time. This determination will be made based on discussions among the Veteran, the Veteran‟s VA primary care provider and the staff at the Baltimore DU Follow-up Program.
24 hour DU excretion test does NOT measure any impact on kidney function or any health effect of the DU. Annual measures of kidney function (BUN, creatinine, and urinalysis) as indicators of a possible health effect, would be prudent (as indicated) and likely reassuring to the Veteran,
Extensive amounts of DU weaponry has been used in US conflicts since 1991 Operation Desert Shield/ Desert Storm Persian Gulf War. Levels of DU exposure are highly variable among deployed troops Newspaper articles and conference reports have reported dramatic increases in cancer and birth defects in Iraqi locals in areas heavily contaminated with DU (Basrah)
Limitations in data make interpretation impossible No formal studies have been conducted to clarify this issue
Evidence-based reviews of available scientific data have concluded:
It is biologically plausible that very high exposures to natural uranium for prolonged periods may cause cancer
This is not proven in epidemiological research
DU is less radioactive than naturally occurring uranium DU potentially poses a chemical hazard at very high levels, but Gulf War exposure levels are unlikely to produce long-term excess morbidity or mortality from kidney, hematological, reproductive or malignant diseases
Institute of Medicine. Gulf War and Health: Volume 1 - Depleted Uranium, Pyridostigmine Bromide, Sarin, Vaccines. Washington, DC: National Academy Press; 2000. Institute of Medicine. Gulf War and Health: Updated Literature Review of Depleted Uranium. Washington, D.C.: National Academy Press; 2008. McDiarmid, MA, Engelhardt, SM, Dorsey, CD, et al. “Surveillance results of depleted uranium-exposed Gulf War I Veterans: sixteen years of follow-up.” J Toxicol Environ Health A. 2009;72(1):14-2989 McDiarmid, MA, Engelhardt, SM, Oliver, M, et al. “Health surveillance of Gulf War I Veterans exposed to depleted uranium: Updating the cohort.” The Radiation Safety Journal. 2008; 93(1):60-73. McDiarmid MA, Engelhardt S, Oliver M, et al. “Health effects of depleted uranium on exposed Gulf War Veterans: A 10year follow-up.” J Tox Environ Health 2004;67:277-96. McDiarmid MA, Engelhardt SM, Oliver M. “Urinary uranium concentrations in an enlarged Gulf War Veteran cohort.” Health Phys 80; 270-273: 2001. McDiarmid MA, Squibb K, Engelhardt, et al. “Surveillance of depleted uranium exposed Gulf War Veterans: Health effects observed in an enlarged „friendly fire‟ cohort.” JOEM 2001;43(12):991-1000. McDiarmid MA, Squibb K, Engelhardt, et al. “Biological Monitioring for Urinary Uranium in Gulf War 1 Veterans.” Health Phys 2004;87(1):51-56.
Parkhurst MA, Daxon EG, Lodde GM, et al. Uranium Aerosol Doses and Risks: Summary of U.S. Assessments (Capstone Report). Richland, WA: Pacific Northwest National Laboratory; Oct, 2004. Research Advisory Committee on Gulf War Veterans‟ Illnesses Gulf War Illness and the Health of Gulf War Veterans: Scientific Findings and Recommendations Washington, D.C.: U.S. Government Printing Office, November 2008 Royal Society. The health hazards of depleted uranium munitions - Part 1. London. May, 2001. Royal Society. The health hazards of depleted uranium munitions - Part 2. London. March, 2002. Squibb K & McDiarmid MA. “Depleted uranium exposure and health effects in Gulf War Veterans.” Phil Trans R Soc 2006; 361:639-48. U.S. Army Center for Health Promotion and Preventive Medicine http://chppm-www.apgea.army.mil/documents/FACT/65-050-0503.pdf U.S. Department of Defense, Office of the Special Assistant for Gulf War Illnesses. Environmental Exposure Report: Depleted Uranium in the Gulf (II). Washington, D.C. Dec 13, 2000. VHA Handbook 1303.1 “Evaluation Protocol for Gulf War and Iraqi Freedom Veterans with Potential Exposure to Depleted Uranium (DU)” (September 2, 2004). http://www1.va.gov/vhapublications/ViewPublication.asp?pub_ID=1158 World Health Organization. Depleted Uranium: Sources, Exposures and Health Effects. Geneva, Switzerland. Apr, 2001. WHO/SDE/PHE/01.1.