toxcentre

Toxicology Reflections

Risk perception of uranium used for military purposes-Author Sarah Crawford

16 Comments

Many people hear the word uranium (U) and think of Chernobyl, or more recently Fukushima. The risk of possible nuclear disasters is a difficult one to communicate to the public. Nevertheless, risk incorporates both effects and probability of exposure, which is an important distinction needed in assessing the risk of U use in society. Exposure to U from nuclear energy production (and resulting “nuclear disaster”) may produce more severe adverse effects, but are less likely to occur than effects associated with exposure to U via metal mining, U containing fertilizers, or from depleted uranium (DU) incorporated into ammunition and military armour. Thus, the risk of U should focus on both effects of U exposure and the likelihood of U exposure.
U is a naturally occurring metal that displays both chemically toxic and radiotoxic properties. U consists of three radioactive isotopes (238U -99.27%, 235U –0.72%, and 234U –0.0057% abundance), emitting alpha particles in the decay process. Thus, U particles do not easily penetrate and are considered to be weakly radioactive due to the long half-lives of U isotopes (105-109 years) (ATSDR, 1999). Radiotoxic effects can thus only occur from internal exposure of U because alpha particles cannot travel far through air and do not penetrate clothing.
Investigation of the radiotoxic and chemotoxic effect of U peaked in the 1990’s due to the increasing use of DUenhanced armour and munitions. DU is a by-product of U enrichment processes, and as a result contains less 235U than natural U and has 60% less radioactivity than natural U (Bleise et al. 2003; McDiarmid et al. 2000).  Due to the high density of DU, its availability, and low cost, DU is favoured for military use and is considered effective because of its self-sharpening and pyrophoric abilities. DU is incorporated in defensive armour plating and armour-piercing projectiles. However, there is a growing concern regarding the potential long-term impacts on human health for both military personnel and civilians exposed to or surrounding high conflict areas. Particular interest arose from veterans that fought in the Gulf War and reported a variety of symptoms that are referred to as the “Gulf war syndrome” (Bleise et al. 2003). Conflicting reports have been published over the last two decades suggesting two extremes; (1) there is no evidence that DU is causing adverse effects, and (2) DU exposure is responsible for a number of cancer and non-cancer health effects.

It  is generally  concluded  that  due  to the  low- specific  activ ity  of DU, chemical  toxicity  is  the  more  significant contributor to DU effects in humans, with the kidney considered to act as the critical target organ (McDiarmid et al. 2000; Squibb et  al. 201 2). Howev er, effects from radiation should not  be completely  disregarded as results from in vitro tests with human osteoblast cells hav e shown that radiation can play a role in DU- induced biological effects (Miller et al. 2002). Other target receptors of DU exposure in humans include the brain, liv er, heart, lung, and other sy stems (Lestaev el et al. 2005; Bleise et al. 2003; WHO, 2001 ).   The pathway s for exposure of DU include ingestion, inhalation and dermal routes. Ingestion of DU can occur from direct ingestion of contaminated soil and consumption of contaminated water, but is not considered a major exposure pathway (Bliese et al. 2003). Dermal  exposure can occur via  embedded  fragments,  shrapnel contamination,  or wound contamination from depleted U oxides in the form of dust. Nev ertheless, dermal exposure is considered a relativ ely unimportant route since little DU will pass across the skin into the blood (WHO, 2001 ). Inhalation is considered the major route of exposure  for  DU in both combat  and non- combat  situation.DU aerosols arise  from impacts  of DU- enhanced projectiles with hard surfaces creating dust containing U oxides, which can accumulate in the lungs.

Debate has arisen with regard to the actual outcomes of acute and chronic exposure of DU. Some believe and have concluded that the human epidemiological evidence is in support of increased risk of birth defects in offspring from those exposed to DU (Hindi et al. 2005). In addition to reproductive effects conclusions from epidemiological studies and animal toxicity tests have suggested DU has immunotoxic, neurotoxic, carcinogenic and leukemogenic potential (Briner and Murray 2005; Lestaevel et al. 2005; Miller et al. 2005). In contrast, the World Health Organization and other studies have concluded that there is no risk of reproductive, developmental, or carcinogenic effects in humans due to DU exposure (Bleise et al. 2003, McDiarmid et al. 2013; WHO, 2001). A twenty year follow-up of a DU exposed military cohort confirmed previous evidence that there are no U-related health effects in organ systems known to be targets of U in an extensive general health assessment in veterans (McDiarmid et al. 2013). Criticism of reproductive toxicity arise in the difficulty to establish a causal pathway between human parental DU exposure and the birth defects of offspring. Hindi et al. (2005) highlights that the mechanism by which DU is internalized and reaches reproductive cells is still not fully understood. Another drawback is that epidemiological studies must deal with the separation of DU exposure from other teratogens and the limited available documentation of individual parental exposure to DU.  There is also an uncertainty regarding the long term radiation effects, with little information stated in the literature about dose-response curves for health effects caused by radiation exposure.

It is understandable that society likes to be caution when it comes to health effects in connection with possible radiation and/or chemical toxicity of uranium. Studies are needed to improve our understanding of the extent, reversibility, and possibility of threshold levels for kidney and other target organ damage. Toxicity will be a function of route of exposure, particle solubility, contact time, and rate of elimination. WHO (2001) has set a tolerable daily intake (TDI) of 0.5 μg/kg BW/d for soluble U (more toxic) and 5 μg/kg BW/d for insoluble (less toxic), with an inhalation limit of 1 μg/m3 (either U solubility). As discussed in class, background exposure may also be important in assessing the estimated exposure to a contaminant and should be considered. Background exposure of DU to civilians include use of DU in counterweights of aircrafts, industrial radiography equipment, radiation shielding in medical radiation therapy, and containers used to transport radioactive materials (Bleise et al. 2003). One of the uncertainties in the population studies of veterans in the Gulf war includes pre-war exposure of DU and overall health assessments. Better characterisation of exposure before, during and after use in conflict will allow countries to better assess the risk associated with DU use for military purposes. However, a bias might exist in countries that put more weight on the benefit of DU use in their militaries, while others are concerned with the potential but unproven long-term health effects of DU. Overall, the risk of DU is a controversial topic with many viewpoints, some of which should be considered with caution.

References

[ATSDR] Agency for Toxic Substances and Disease Registry. 2013. Toxicological profile for Uranium. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service. http://www.atsdr.cdc.gov/toxprofiles/TP.asp?id=440&tid=77

Bleise, A., Danesi, P. R., and Burkart, W. (2003). Properties, use and health effects of depleted uranium (DU): a general overview. Journal of Environmental Radioactivity, 64(2), 93-112. http://iaea.org/newscenter/focus/depleteduranium/properties.pdf

Briner, W., and Murray, J. (2005). Effects of short-term and long-term depleted uranium exposure on open-field behavior and brain lipid oxidation in rats. Neurotoxicology and teratology, 27(1), 135-144. http://www.sciencedirect.com/science/article/pii/S0892036204001321

Hindin, R., Brugge, D., and Panikkar, B. (2005). Teratogenicity of depleted uranium aerosols: a review from an epidemiological perspective. Environmental Health, 4(1), 17. http://www.ehjournal.net/content/4/1/17

Lestaevel, P., Houpert, P., Bussy, C., Dhieux, B., Gourmelon, P., and Paquet, F. (2005). The brain is a target organ after acute exposure to depleted uranium. Toxicology, 212(2), 219-226. http://laka.org/docu/boeken/pdf/6-05-0-00-27.pdf

McDiarmid, M. A., Keogh, J. P., Hooper, F. J., McPhaul, K., Squibb, K., Kane, DiPino, R., Kabat, M., Kaup, B., Anderson, L., Hoover, D., Brown, L., Hamilton, M., Jacobson-Kram, D., Burrows, B. and Walsh, M. (2000). Health effects of depleted uranium on exposed Gulf War veterans. Environmental Research, 82(2), 168-180.
http://ac.els-cdn.com/S0013935199940124/1-s2.0-S0013935199940124-main.pdf

McDiarmid, M. A., Engelhardt, S., Oliver, M., Gucer, P., Wilson, P. D., Kane, R., and Squibb, K. S. (2004). Health effects of depleted uranium on exposed Gulf War veterans: a 10-year follow-up. Journal of Toxicology and Environmental Health, Part A, 67(4), 277-296. https://143.84.106.6/downloads/Env_Health%20Effects_DU.pdf

Miller, A. C., Xu, J., Stewart, M., Brooks, K., Hodge, S., Shi, L., Page, M. and McClain, D. (2002). Observation of radiation-specific damage in human cells exposed to depleted uranium: dicentric frequency and neoplastic transformation as endpoints. Radiation protection dosimetry, 99(1-4), 275-278. http://rpd.oxfordjournals.org/content/99/1-4/275.short

Miller, A. C., Bonait-Pellie, C., Merlot, R. F., Michel, J., Stewart, M., and Lison, P. D. (2005). Leukemic transformation of hematopoietic cells in mice internally exposed to depleted uranium. Molecular and cellular biochemistry, 279(1-2), 97-104. http://www.nukewatchinfo.org/du/leukemiainmice2005.pdf

Squibb, K. S., Gaitens, J. M., Engelhardt, S., Centeno, J. A., Xu, H., Gray, P., & McDiarmid, M. A. (2012). Surveillance for long-term health effects associated with depleted uranium exposure and retained embedded fragments in US veterans. Journal of Occupational and Environmental Medicine, 54(6), 724-732. http://journals.lww.com/Surveillance_for_Long_Term_Health_Effects.11.aspx

[WHO] World Health Organization. (2001). Depleted Uranium, Sources, Exposure and Health Effects. WHO, Geneva. http://www.who.int/ionizing_radiation/pub_meet/en/DU_Eng.pdf

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16 thoughts on “Risk perception of uranium used for military purposes-Author Sarah Crawford

  1. Sarah,
    This topic I find really interesting because I lived in Kuwait for 6 years. There would be occassional intense sand
    storms that would last for days. I often wondered about what I was breathing in along with all those fine particles.
    In the first Gulf War, depleted uranium munitions were used all over Kuwait. Many of the most contaminated
    sites were outside the city but I often wondered what my exposure due to inhalabition was during these sand
    storms. The Internaitonal Atomic Energy Agency (IAEA) conducted a study in Kuwait in 2002 to determine the
    radiological hazard of depleted uranium left from the war but they do not go into detail about the chemical hazard
    of depleted uranium exposure and they do not consider chronic inhalation exposure due to sand storm events (1).
    I was also curious about the fate of depleted uranium in the environment?
    IAEA. 2003. Radiological Conditions in Areas of Kuwait with Residues of Depleted Uranium. Radiological
    Assessment Report Series. Vienna, Austria.
    http://www-pub.iaea.org/MTCD/publications/PDF/Pub1164_web.pdf

    • Those are some great points to consider when trying to understand the exposure and risk of DU. Certainly sand storms would carry particles of DU that can be inhaled by civilians in and around the city of Kuwait. Again, contamination through dust inhalation is probably the most significant exposure for workers, soldiers, and civilians. Interestingly, I would imagine sand storms can also contribute to deposition of DU in the city and on the skin of civilians that can lead to ingestion of contaminated soils or dust. Monleau et al. (2005) conducted a study investigating the effects of DU in rats exposed to repeated inhalations and found insoluble DU accumulated in the brain but differentially. Chronic exposures to DU fragments or acute injections have also demonstrated that U can cross the blood-brain barrier in rats but accumulation occurred heterogeneously in the brain, with distribution shown to be dose dependent (Barber et al. 2005; Pellmar et al. 1999). Studies with cats and dogs have also demonstrated neurological effects of DU via inhalation, with symptoms of muscular weakness, instability of gait and anorexia (Monleau et al. 2005). However, it is clear that the mechanisms of transport and accumulation in the brain is unknown which may explain the variation in central nervous system (CNS) symptoms reported in studies.
      There is currently no evidence of excessive neurological disease or mortality after exposure to DU in humans (Monleau et al. 2005), which is good for you Ryan. Some of the noted symptoms of humans, particularly those
      associated with Gulf War veterans, include depression or agitation in those exposed to high concentrations of U, as well as cognitive impairment (Monleau et al. 2005). Evaluations following the Gulf War demonstrated a significant
      relationship between elevated urinary U excretion and declining performance efficiency in soldiers injured by DU fragments, but was not found to be present in a 10-year follow-up (McDiarmid et al. 2004). The difficulty in
      assessing effects from DU exposure, let alone chronic exposure through sporadic events such as sand storms lies in our ability to quantify exposure. I’ll discuss this in further detail in later posts. Ultimately, uncertainty exists in
      the link between DU exposure and effects on the CNS in humans. Carla, this may offer an explanation for the variation of symptoms reported by veterans experiencing the Gulf War Syndrome in addition to the multiple routes of exposure some of the veterans experienced.

      References:

      Barber, D. S., Ehrich, M. F., & Jortner, B. S. (2005). The effect of stress on the temporal and regional distribution of uranium in rat brain after acute uranyl acetate exposure. Journal of Toxicology and Environmental Health,
      Part A, 68(2), 99-111. http://www.tandfonline.com/doi/abs/10.1080/15287390590885910#.Ujn27mbnYuY

      McDiarmid, M. A., Engelhardt, S., Oliver, M., Gucer, P., Wilson, P. D., Kane, R. & Squibb, K. S. (2004). Health effects of depleted uranium on exposed Gulf War veterans: a 10-year follow-up. Journal of Toxicology and
      Environmental Health, Part A, 67(4), 277-296. https://143.84.106.6/downloads/Env_Health%20Effects_DU.pdf

      Monleau, M., Bussy, C., Lestaevel, P., Houpert, P., Paquet, F., & Chazel, V. (2005). Bioaccumulation and behavioural effects of depleted uranium in rats exposed to repeated inhalations. Neuroscience letters, 390(1), 31-
      36. http://www.sciencedirect.com/science/article/pii/S0304394005008797

      Pellmar, T. C., Fuciarelli, A. F., Ejnik, J. W., Hamilton, M., Hogan, J., Strocko, S. & Landauer, M. R. (1999). Distribution of uranium in rats implanted with depleted uranium pellets. Toxicological Sciences, 49(1), 29-39.
      http://toxsci.oxfordjournals.org/content/49/1/29.full.pdf
      Thread: Risk

  2. I am very interested in the Gulf War Syndrome, which I investigated in greater detail. It was reported by the ResearchAdvisory
    Commite on Gulf Was Illness (2008) that 210,000 of 700,000 U.S. veterans who served in the 1990-1991 Gulf War suffer with one
    or more symptoms of this syndrome. Symptoms usually include a combination of memory and concentration problems, persistent
    headache, unexplained fatigue, and widespread pain, and can also include chronic digestive difficulties, respiratory symptoms, and skin
    rashes. Similarly, the same symptoms have been described in veterans from United Kingdom and other allied countries who have fought in the Gulf War. Considering the potential exposure of veteran, and the in vitro studies in DU addressed by you, why is there
    so much uncertainty regardless of the chronic effects of DU in veterans? Can you describe more how DU toxicity is associated with
    observed effects in veterans?

    Research Advisory Committee on Gulf War Veterans’ Illnesses (2008) Gulf War Illness and the Health of Gulf War Veterans:
    Scientific Findings and Recommendations. Washington, D.C.: U.S. Government Printing Office, November 2008.

  3. Depleted uranium (DU) exposure to humans from military incorporation into ammunition and armour is not the
    first instance of U effects studied in humans. A substantial amount of information regarding U exposure is
    available on U miners, millers and other processors worldwide. Uranium exposure often leads to renal toxicity;
    however, several epidemiological studies have found no increased mortality in U workers due to renal disease
    (Craft et al., 2004). The US Centers for Disease Control (CDC) and Prevention/Agency for Toxic Substances and
    Disease Registry (ASTDR) has concluded that “no significant differences in cancer [of the lungs] was found
    between workers who are occupationally exposed to uranium and control populations” (ASTDR, 2013). The US
    National Academy of Sciences Institutes of Medicine also evaluated the existing epidemiological literature
    available and concluded that there is limited evidence of association between exposure to U and lung cancer at
    cumulative internal dose levels lower than 200 mSv or 25 cGy. To put this dose in perspective, 200 mSv is
    roughly equivalent to a full year’s exposure to a dusty indoor U workshop environment (Donoghue, 1972). Risk of
    cancer cannot be ignored though as some epidemiological studies indicate a correlation between U mining nad
    milling and incidence of DNA-damaging effects resulting in carcinogenesis in humans (Craft et al., 2004). Overall,
    there is currently inadequate or insufficient evidence to determine the health implications with regard to
    carcinogenic endpoints (ASTDR, 2013).
    Discussions in class suggested that population studies are useful in compiling and assessing exposure to humans
    and can be refined to answer certain questions that may be of interest (i.e., mercury levels and fish eating
    populations). One of the largest cohort studies investigating the effects of U and radium (Ra) compound exposure
    from ore dust and radiation on U processing workers was conducted in Port Hope, Ontario. The Port Hope Ra and
    U refinery and processing plant became operational in 1932 and continues to operate today as Cameco Corp. Port
    Hope Conversion Facility. This study by Zablotska et al. (2013) included participants employed between 1932-1980 (including 3000 male and female workers) and examined mortality (1950 – 1999) and cancer incidence
    (1969 – 1999). No significant radiation-associated risks were observed for any cancer or cause of death, with
    workers demonstrating a lower mortality and cancer incidence compared with the general Canadian population
    (Zablotska et al., 2013). This conclusion is in agreement, as discussed previously, with a study of veterans involved
    with friendly fire that also concluded no cancer risks were evident due to U exposure (McDiarmid, 2000).
    Overall, fifty years of extensive research on workers who mine and process U has not revealed significant adverse
    health effects associated with U exposure. I think it would be beneficial to utilize the evidence in informing the
    public about potential health risk and more importantly in guiding exposure prevention activities. Despite
    reputable agencies claiming little human health effects, the public perception of DU effects in humans is still one of
    concern. As Lorelei and others have mentioned in discussions, the shortcomings with risk communication arise in
    the lack of familiarity with a hazard, which increase the public perception of risk. Thus, if we can determine a way
    to effectively communicate the science jargon, we may have a better chance of allowing use of DU ammunition for
    military purposes (which is a whole other non-toxicology related debate).

    REFERENCES:

    [ATSDR] Agency for Toxic Substances and Disease Registry. 2013. Toxicological profile for Uranium. Atlanta, GA:
    U.S. Department of Health and Human Services, Public Health Service.
    http://www.atsdr.cdc.gov/toxprofiles/TP.asp?id=440&tid=77

    Craft, E. S., Abu-Qare, A. W., Flaherty, M. M., Garofolo, M. C., Rincavage, H. L., & Abou-Donia, M. B. (2004).
    Depleted and natural uranium: chemistry and toxicological effects. Journal of Toxicology and Environmental
    Health, Part B, 7(4), 297-317.
    http://www.dmzhawaii.org/wp-content/uploads/2009/02/health-overview-04.pdf

    Donoghue, J. K., Dyson, E. D., Hislop, J. S., Leach, A. M., & Spoor, N. L. (1972). Human exposure to natural
    uranium: A case history and analytical results from some postmortem tissues. British journal of industrial
    medicine, 29(1), 81-89. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1009355/pdf/brjindmed00097-
    0085.pdf

    McDiarmid, M. A., Keogh, J. P., Hooper, F. J., McPhaul, K., Squibb, K., Kane, DiPino, R., Kabat, M., Kaup, B.,
    Anderson, L., Hoover, D., Brown, L., Hamilton, M., Jacobson-Kram, D., Burrows, B. and Walsh, M. (2000). Health
    effects of depleted uranium on exposed Gulf War veterans. Environmental Research, 82(2), 168-180.
    http://ac.els-cdn.com/S0013935199940124/1-s2.0-S0013935199940124-main.pdf

    Zablotska, L. B., Lane, R. S., & Frost, S. E. (2013). Mortality (1950–1999) and cancer incidence (1969–1999) of
    workers in the Port Hope cohort study exposed to a unique combination of radium, uranium and γ-ray doses. BMJ
    open, 3(2). http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3586082/

    • Sarah,
      I really enjoy reading your posts!
      One concern I have always had with DU is the idea that once it used for military purposes (e.g. weapons) it is no
      longer ‘controlled’. As I understand it, here in Canada, the Canadian Nuclear Safety Commission has a mission to
      ensure the ‘peaceful use of nuclear energy’ by closely regulating industry and internationally tracking or at least
      attempting to ensure the responsible use of uranium and its derivatives. From our point of view, uranium is
      highly controlled and we feel relatively safe. Perhaps our workers don’t experience higher cancer rates and to
      some extent the hormesis effect even makes their lives better; however, once enriched and spent, the use of DU in
      other countries where it is not controlled is (in my opinion) nothing short of irresponsible.
      Decisions to use DU for military purposes must have more benefit than cost from one point of view; however, I
      don’t believe that the humans exposed to DU in most cases understand and accept those risks. Furthermore, it
      would concern me if they also had a limited ability to cope with the removal of DU scattered throughout their
      environments but also the health implications should they arise. I found an article by Handley-Sidu et al. 2010
      that clearly explains the reasoning for using DU for military purposes and the tonnage of DU used in conflicts
      starting in the 1990s. It was especially interesting that the US has not disclosed their contribution of DU to the
      Iraq War but that the UNEP (2007 cited in Handley-Sidu et al. 2010) estimates that 170-1700 tonnes were
      released to the environment. How would you even begin to accurately determine exposure?
      I understand that nations can justify the use of DU for military purposes and perhaps given the circumstances we
      would all agree its use was necessary; however, this may be a case where the human health risks and
      environmental risks require a more holistic approach. For example, if I had to live in an environment riddled by
      DU shrapnel I think there would be negative health effects (e.g. stress and anxiety associated with the
      unknown/future health affects) that would occur regardless of whether or not I developed cancer. I wonder if risk
      assessments involving DU have taken into account other contributions to risk other than simply the human health
      end points.
      Handley-Sidu et al. 2010 go on to describe the fate and bioavailability of DU in the environment which is relevant
      to the background concentrations that humans would be exposed to over time under certain environmental
      conditions.
      Very interesting read! I hope you are going to talk about the health risks associated with the storage of (D)UF6 in
      the future as well!
      Stephanie Handley-Sidhu, Miranda J. Keith-Roach, Jonathan R. Lloyd, David J. Vaughan. 2010. A review of the
      environmental corrosion, fate and bioavailability of munitions grade depleted uranium. Science of The Total
      Environment, Volume 408, Issue 23, 1 November 2010, Pages 5690–5700
      http://dx.doi.org/10.1016/j.scitotenv.2010.08.028

  4. I really liked what Jenna said about incorporating risk assessment into high school curriculums. It seems to be
    that public perception is coming up across a lot of our topics here. I also find it interesting because I have a sister
    who is in advanced science courses in high school and in her course material there is almost nothing about human
    or environmental risks. They are kind of taught in a very straight forward manner of this is good and this is bad
    and that’s that. Something along the lines of our discussions here I think would go a long way in improving public
    knowledge. So it’s probably really good that we all discussed the opening of this board to the public.

  5. I completelly agree! there is a complete lack of public education on risk assesment, which is indded surprising
    when it is something that we all do all day every day. And the best is that at a high school level, this training would be as easy as citing Paracelsus and make them understand that absolutely everything can be toxic and that it all
    depends on the dose. A couple of nice examples, and i believe there would be no more cases of nonsense! just
    objective, scientifically based evaluation of facts.
    sorry for the rant. 🙂

  6. This week I wanted to focus on the alternatives to DU and whether or not these are any less harmful to humans,
    but I think Lorelei bring up some really great points regarding exposure that should be addressed. So spoiler for
    next week: watch out for tungsten used as an alternative to DU!
    One of the major uncertainties with DU exposure via military uses is the sheer number of ammo used during
    conflict and what happens after the fighting is done. There are many estimates of the tonnage of DU used in
    conflict that are likely still found in the environment. The only certain exposure that can be tracked over a longterm
    period is via fragments of shrapnel contamination that remain in the body of a soldier. However, McDiarmid
    et al. (2004) has investigated health effects in a formal 10-year follow-up of veterans that retained fragments of
    DU in their tissue that concluded no evidence of significant health effects.
    Methods used to estimate exposure of DU range in their ability to obtain health information of the person exposed prior to and post-conflict, the types of exposure that occurred during conflict, and in the relevance of measurement endpoints for DU exposure. In a cohort study of thirty-two veterans, urine U concentrations were
    determined and indicated that soldiers possessing embedded DU fragments continue to excrete elevated concentrations of U in urine (McDiarmid et al. 2006). However, no clinically significant U related health effects were observed in blood count, blood chemistries (including renal markers), neuropsychological measures, and semen quality (McDiarmid et al. 2006). These are all endpoints which would indicate effects of individuals exposedto DU, but despite continuous chronic expose little evidence of adverse effects are apparent.
    One area of research where uncertainty exists is in the measures of genotoxicity, which have shown elusive results (McDiarmid et al. 2006). As someone who works closely with U, I find it interesting (and a relief) that chronically elevated U concentration in the urine can still be detected with no observed clinical abnormalities. I should note
    though, the U burden in this cohort study is relatively low compared to historical U exposed occupational groups mentioned in last week reflection. I think the importance of these cohort studies and occupational exposure studies rests in our ability to gather information that will improve our understanding and assessment of soldiers in
    which we are unable to accurately estimate U exposure. Perhaps it will allow us to set limits to the amount of DU munitions used in conflict, particularly if exposure assessments are to reflect potential exposure of civilians post conflict.
    Civilian exposure, as a result of scattered DU fragments in an area of conflict does unfortunately appear to be an issue, one that is not incorporated in assessments of risk prior to war. Environmental impact assessments of DU in post conflict zones are available and suggest that there is limited evidence of environmental DU contamination
    except in areas surrounding damaged tanks and vehicles (Handley-Sidhu et al. 2010). I found it interesting that the Handley-Sidhu et al. (2010) study stated that approximately 90% of penetrators fired from aircraft missed their target, and due to the properties of DU munitions, these often ended up below the soil surface. UNEP (2002) concluded that based on corrosion rate of penetrators retrieved from soils in Serbia and Montenegro, penetrators would be completely corroded within 20 years. So the large tonnage of DU munitions used during the conflicts in
    the 1990’s would be expected have fully corroded by now, which raises the question if the DU is now part of the top soils in these areas would this increase exposure due to inhalation and ingestion of soil and dust particles containing DU?
    Overall, there is a unique uncertainty associated with DU exposure in the case of DU military use in wars that I think would be quite different from a product used in cosmetic or other personal care products used on a daily basis. Ultimately, the uproar after the large use of DU munitions during the 1990s has made the world more aware of the potential chronic health effects or rather uncertainty in our knowledge of chronic effects. Currently there is little evidence to suggest adverse human health effects, but perhaps alternatives should be investigated (RE: next week’s post) or ideally, peaceful conflict resolution should be employed (or one could hope)!

    References:

    Handley-Sidhu, S., Keith-Roach, M. J., Lloyd, J. R., & Vaughan, D. J. (2010). A review of the environmental
    corrosion, fate and bioavailability of munitions grade depleted uranium. Science of the Total Environment,408(23), 5690-5700.
    http://ac.els-cdn.com/S0048969710008892/1-s2.0-S0048969710008892-main.pdf?_tid=91a56bb4-2bc5-11e3-9815-00000aab0f26&acdnat=1380761510_7a479b2f8cee1483164e5b660be7323d

    McDiarmid, M. A., Engelhardt, S., Oliver, M., Gucer, P., Wilson, P. D., Kane, R., … & Squibb, K. S. (2004). Health
    effects of depleted uranium on exposed Gulf War veterans: a 10-year follow-up. Journal of Toxicology and
    Environmental Health, Part A, 67(4), 277-296. https://143.84.106.6/downloads/Env_Health%20Effects_DU.pdf

    McDiarmid, M. A., Engelhardt, S. M., Oliver, M., Gucer, P., Wilson, P. D., Kane, R., … & Squibb, K. S. (2006). Biological monitoring and surveillance results of Gulf War I veterans exposed to depleted uranium. International archives of occupational and environmental health, 79(1), 11-21.
    https://143.84.106.6/downloads/McDiarmid_article_on_2003_DU_surveillance_Aug_05_082205.pdf

    UNEP (United Nations Environmental Programme). 2002. Depleted uranium in Serbia and Montenegro:
    Postconflict environmental assessment in the Federal Republic of Yugoslavia. http://postconflict.unep.ch/publications/duserbiamont.pdf

    P.S. I the storage of UF6 fastinating especially with everything happening in Japan – so I will try to bring it into
    discussion 🙂

    • Also when you stated “I wonder if risk assessments involving DU have taken into account other
      contributions to risk other than simply the human health end points.” What other contributing factors are you
      referring to? Is it to do with the stress of war and the physical health impacts that result from anxiety and stress?
      I wonder if these seem more of a concern based on the severity of war compared to say a mother’s oftensmothering
      stress and anxiety of harmful products such as BPA in their children’s bottles.

  7. Really great points ladies! I like the idea of discussing how to improve our education in an effort to reduce unfounded risk
    perception. I also knew very little about U before moving to Saskatchewan. I find even educated scientists are often wary
    of me when I mention I work with U, with the typical “do you glow in the dark” questions asked. I think anything to do with
    such a controversial and “scary” contaminant such as U which is usually perceived to employ radioactive endpoints is due to
    misconception. Plus with U there are multiple routes of exposure from the point of mining to tailings to conversion, use in
    nuclear production and in the end depleted uranium which is either stored or used for military purposes. This can lead to a
    number of erroneous assumptions of risk at each of these stages. Perhaps it would be useful if I discuss some of these
    processes in the upcoming posts (especially if these will be made available to the public).
    Thanks for the comments!

  8. Ya, not really having to do with the stress of war but rather the alternative options people face because of the
    perceived risk posed by DU. For example, let’s pretend that I have children and they like to play in a playground
    near my home. War breaks out and I know that there is residual material scattered about the playground that
    contains DU. Me and the other moms know that it contains something dangerous so we tell our children not to
    play outside just in case they touch or play with shrapnel that contains DU. Also, I stop gardening because there is
    some understanding that DU residuals may be in the soil or water. Perhaps it is not just me that does this but
    many families and it continues for a long period of time. Could that increase overall health risk associated with
    DU because now my family doesn’t eat as well as they used to and my children aren’t fit because they no
    longer play outside.
    I would hypothesize that the overall health risks associated with the use of DU may increase. These thoughts
    stem from converstaions I have had with others but am still trying to get my head around it.
    Thanks for the tungsten spoiler! I really am excited. 🙂

  9. Sorry Pepe, my page must not have refreshed, so I retract my “really good points ladies” and change it “really
    good points you guys”! haha
    Sarah Crawford
    Thread:

  10. I also like that map. You are right about people being surprised to see high concentrations of uranium in
    their drinking water. I run across it frequently at work. Shockingly, I also speak to a lot of people that don’t feel
    that concerned about the uranium in their water. They usually go on to explain that 2-3 generations of their
    family lived on that land, drank the water, someone lived to be 90, and ergo the water is safe. Perhaps the
    uranium provides a little hormesis effect? For fun, check out this strange little website: http://radiationhormesis.
    com/.
    Great discussion Sarah! Very interesting and controversial topic.

  11. This is an awesome discussion! It is interesting how reading this post I am re-evaluating my own perception
    about U. Even though we are sharing the same office for more than 2 years, I never had a clear idea of the risk of
    U exposure. All the ideas about introducing risk assessment to high school students are great. Not only to inform
    them about unfounded public communication, but also to stimulate their critical viewing. Here some interesting
    papers about risk perception (1, 2 and 3).

    Those suggestions are definitely relevant; however they will result in an intermediate to long term changes. I
    wonder what is being done to change public perception about U exposure. If not in a large scenario, do you know
    any campaign that might be doing some work in U risk perception on communities nearby U mines?

    1- 1- Slovic P. Perception of risk. Science, 236:280, 1987.

    2- 2- Goodfellow et al. Nuclear renaissance, public perception and design criteria: An exploratory review. Energy
    Policy, 39(10):6199–6210, 2011.

    3- 3- Ropeik. Risk Perception in Toxicology—Part I: Moving beyond Scientific Instincts to Understand Risk
    Perception. Toxicological Science 1210(1): 1-6, 2011.

  12. The advantages and disadvantages of depleted uranium (DU) used in military application have been discussed
    throughout this post in reference to potential adverse human health effects. However, with a controversial topic
    such as DU and the potential concern over health effects due to DU exposure, consideration and investigation into
    alternatives can arise. This occurred in the early 2000’s particularly with reports of “Gulf War Syndrome” in
    which DU was blamed for a number of symptoms observed in veterans returning from war. DU was incorporated
    into 30-mm ammunition that was used by the American A-10 “tank buster” aircrafts, which as Lorelei pointed out included hundreds of tonnes of DU munitions fired during the Gulf and Balkan conflicts throughout the 1990s.
    Thus, this continuing concern and uncertainty regarding the potential human and environmental effects of DU led
    to many countries incorporating tungsten alloy based munitions as replacements.
    A prototype ammunition that included a “liquid metal” alloy was investigated by the US Army (Hambling, 2003).
    The replacement material of choice was an alloy of tungsten (W), which has a similar density to U. Other positive
    properties of tungsten alloys (WAs) include the self-sharpening and pyrophoric properties which make U such an
    effective penetrator. A perceived benefit of replacing DU with WAs in military applications was that WAs are
    non-radioactive so there is no uncertainty regarding radiotoxic effects occurring in conjunction with potential
    chemical effects. Unfortunately, the health impacts of WAs are not fully understood and there is a lack of longterm
    chronic studies available. Contributing to the lack of knowledge of these WA replacements is that they are
    typically composed of a mixture of W (91-93%), Ni (3-5%), and Co (2-4%) particles (Miller at al. 2004).
    There are numerous studies available on the health effects of Ni or Co, but these are not always consistent.
    Carcinogenic endpoints are reported for intramuscular injections of Ni and Co, which is not the case observed with
    intramuscular implantations of pellets composed of various Ni or Co alloys used in orthopedic prosthetics that
    report no excessive tumour formations (Kalinich et al. 2005). The difference in noted effects is disconcerting
    when a major route of long-term exposure of DU and those of WA replacements would be internalization of
    embedded fragments and/or shrapnel in humans. Little information is available on the health effects of this route
    of exposure, with most of the studies focusing on animal tests with conflicting results reported. In a study by
    Kalinich et al. (2005), 92 rats were implanted with pellets of weapons-grade WAs and within 5 months all the
    animals developed a rare cancer called rhabdomyosarcom. In contrast, some believe that elemental W or
    insoluble W compounds may only have limited toxicity. Peuster et al. (2003) investigated W coils implanted into
    the subclavian artery of rabbits and reported rapid degradation of W leading to elevated serum W concentrations
    as early as 15 min after implantation but after 4 months no signs of local or systemic toxicity were observed.
    There are also not many human studies available in the literature, and none of them have examined long-term
    chronic effects of WAs.
    Additional concerns with metal alloys are the combination of various metals that make up the alloy mixture that
    can change based on the method of production. Miller et al. (2004) and others have noted a synergistic effect of
    Ni, Co, and W mixtures that cause a greater toxicity compared to the metals individually. This has led to some
    difficulty in quantifying exposure and can limit the usefulness of literature available on the individual metals. This
    is a disadvantage compared to the decades of research available on historical U exposure data that can be used to
    interpret and improve our understanding of chronic effects of DU exposure on human health effects. Overall, the replacement of “dirty” DU with a “clean” alternative like WAs appears to be another example of
    quick and poor decision-making. Research has continued to look for alternatives and into methods of improving
    the performance of DU penetrators. Most notable, Stakalloy (a combination of U, niobium and vanadium) are
    being re-investigated. But I think we should try to learn from our examples from the past in which compounds
    are replaced when industry starts to get a bad reputation or pressure from a government to reduce its use of a
    “bad” compound. In this instant pressure arose worldwide after the reported human health effects of DU, which
    are still highly debated. Without substantial proof of effects, perhaps more time could have been spent on
    investigating alternative before jumping into using them. I should note, the development of WA replacements has
    not led to many countries ceasing or reducing the use of DU military applications. A big push in the EU has been
    to ban the production and military use of DU weapons, but countries like France, Britain, the Netherlands and the
    Czech Republic have shut down these discussions. I believe the follow—up data on veterans exposed to DU in
    wars has shed some light on chronic health effects in combinations with our years of exposure data and associated
    health effects in mine workers.
    I think the bad reputation uranium receives in the public has a lot to do with the perceived risk of nuclear
    production and associated radiotoxic effects from extreme examples of U exposure. In addition, the use of any
    weapon in war is generally a controversial one with an embedded negative aspect regardless of the human health
    implications. I agree with some of the students posting in these reflections that education is likely the key in
    improving society’s view on U use whether its associated with nuclear energy production or in military weapons. I
    am glad to hear some of you have reassessed your view on U from these posts! Thanks for participating, I’ll be
    happy to keep posting here throughout the rest of the semester and address some of the other issues brought up
    (i.e., U in drinking water and storage and disposal of U in nuclear energy production).

    References:

    Hambling D (2003). “Safe” alternative to depleted uranium revealed. New Scientist.
    http://www.newscientist.com/article/dn4004-safe-alternative-to-depleted-uraniumrevealed.
    html#.UkOWx2bna44

    Kalinich, J. F., Emond, C. A., Dalton, T. K., Mog, S. R., Coleman, G. D., Kordell, J. E., … & McClain, D. E. (2005).
    Embedded weapons-grade tungsten alloy shrapnel rapidly induces metastatic high-grade rhabdomyosarcomas in
    F344 rats. Environmental Health Perspectives, 113(6), 729.
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1257598/

    Miller, A. C., Brooks, K., Smith, J., & Page, N. (2004). Effect of the militarily-relevant heavy metals, depleted
    uranium and heavy metal tungsten-alloy on gene expression in human liver carcinoma cells (HepG2). Molecular
    and Cellular Biochemistry, 255(1-2), 247-256. http://www.nukewatchinfo.org/du/humanlivercancer2004.pdf

    Peuster, M., Fink, C., Wohlsein, P., Bruegmann, M., Günther, A., Kaese, V., … & Haferkamp, H. (2003).
    Degradation of tungsten coils implanted into the subclavian artery of New Zealand white rabbits is not associated
    with local or systemic toxicity. Biomaterials, 24(3), 393-399.
    http://www.sciencedirect.com.cyber.usask.ca/science/article/pii/S0142961202003526

  13. Very interesting map and hormesis links ladies! I had no idea that contact with U is common or that I could self
    medicate at home.

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