Uranium in the environment: Difference between revisions

Source: Wikipedia, the free encyclopedia.
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
KolbertBot (talk | contribs)
Bots
1,166,042 edits
Rescuing 2 sources and tagging 0 as dead. #IABot (v1.6.2) (Balon Greyjoy)
Line 65: Line 65:
===Nuclear waste===
===Nuclear waste===
Spent [[uranium dioxide]] fuel is very insoluble in water, it is likely to release uranium (and [[fission products]]) even more slowly than borosilicate glass when in contact with water.<ref>B.E. Burakov, M.I Ojovan, W.E. Lee. Crystalline Materials for Actinide Immobilisation, Imperial College Press, London, 198 pp. (2010).
Spent [[uranium dioxide]] fuel is very insoluble in water, it is likely to release uranium (and [[fission products]]) even more slowly than borosilicate glass when in contact with water.<ref>B.E. Burakov, M.I Ojovan, W.E. Lee. Crystalline Materials for Actinide Immobilisation, Imperial College Press, London, 198 pp. (2010).
http://www.icpress.co.uk/engineering/p652.html</ref>
{{cite web |url=http://www.icpress.co.uk/engineering/p652.html |title=Archived copy |accessdate=2010-10-16 |deadurl=yes |archiveurl=https://web.archive.org/web/20120309093650/http://www.icpress.co.uk/engineering/p652.html |archivedate=2012-03-09 |df= }}</ref>


Note that while the vast majority of the uranium is removed by [[PUREX]] [[nuclear reprocessing]], a small amount of uranium is left in the [[raffinate]] from the first cycle of the PUREX process. In addition because of the decay of the transplutonium [[minor actinides]] and the residual [[plutonium]] in the waste the concentration of uranium will increase on the waste. This will occur on a time scale of hundreds and thousands of years.
Note that while the vast majority of the uranium is removed by [[PUREX]] [[nuclear reprocessing]], a small amount of uranium is left in the [[raffinate]] from the first cycle of the PUREX process. In addition because of the decay of the transplutonium [[minor actinides]] and the residual [[plutonium]] in the waste the concentration of uranium will increase on the waste. This will occur on a time scale of hundreds and thousands of years.
Line 72: Line 72:
[[File:Trionuraniumanti.png|thumb|right|Tiron is a [[phenol]]oic [[aromatic]] [[sulfonic acid|disulfonic acid]]. It is an alternative to bicarbonate which has already been tested in animals.]]
[[File:Trionuraniumanti.png|thumb|right|Tiron is a [[phenol]]oic [[aromatic]] [[sulfonic acid|disulfonic acid]]. It is an alternative to bicarbonate which has already been tested in animals.]]


Soluble uranium salts are [[toxic]], though less so than those of other heavy metals such as [[lead]] or [[mercury (element)|mercury]]. The organ which is most affected is the [[kidney]]. Soluble uranium salts are readily excreted in the [[urine]], although some accumulation in the kidneys does occur in the case of chronic exposure. The [[World Health Organization]] has established a daily "tolerated intake" of soluble uranium salts for the general public of 0.5&nbsp;μg/kg body weight (or 35&nbsp;μg for a 70&nbsp;kg adult): exposure at this level is not thought to lead to any significant kidney damage.<ref name="IAEA">{{Cite web|url=http://www.iaea.org/NewsCenter/Features/DU/faq_depleted_uranium.shtml |publisher=[[International Atomic Energy Agency]] |title=Focus: Depleted Uranium |accessdate=August 28, 2010}}</ref>{{Failed verification|date=August 2010}}
Soluble uranium salts are [[toxic]], though less so than those of other heavy metals such as [[lead]] or [[mercury (element)|mercury]]. The organ which is most affected is the [[kidney]]. Soluble uranium salts are readily excreted in the [[urine]], although some accumulation in the kidneys does occur in the case of chronic exposure. The [[World Health Organization]] has established a daily "tolerated intake" of soluble uranium salts for the general public of 0.5&nbsp;μg/kg body weight (or 35&nbsp;μg for a 70&nbsp;kg adult): exposure at this level is not thought to lead to any significant kidney damage.<ref name="IAEA">{{Cite web |url=http://www.iaea.org/NewsCenter/Features/DU/faq_depleted_uranium.shtml |publisher=[[International Atomic Energy Agency]] |title=Focus: Depleted Uranium |accessdate=August 28, 2010 |deadurl=yes |archiveurl=https://web.archive.org/web/20100318003818/http://www.iaea.org/NewsCenter/Features/DU/faq_depleted_uranium.shtml |archivedate=March 18, 2010 |df= }}</ref>{{Failed verification|date=August 2010}}


The [[antidote]] for uranium in humans is [[bicarbonate]], which is used because uranium (VI) forms complexes with [[carbonate]]. An alternative is to use tiron (sodium 4,5-dihydroxybenzene-1,3-disulfonate).<ref>{{cite journal |author=O. Braun, C. Contino, M.-H. Hengé-Napoli, E. Ansoborlo and B. Pucci |year=1999 |title=Development of an in vitro test for screening of chelators of uranium |journal=[[Analusis]] |volume=27 |pages=65–68 |doi=10.1051/analusis:1999108}}</ref>
The [[antidote]] for uranium in humans is [[bicarbonate]], which is used because uranium (VI) forms complexes with [[carbonate]]. An alternative is to use tiron (sodium 4,5-dihydroxybenzene-1,3-disulfonate).<ref>{{cite journal |author=O. Braun, C. Contino, M.-H. Hengé-Napoli, E. Ansoborlo and B. Pucci |year=1999 |title=Development of an in vitro test for screening of chelators of uranium |journal=[[Analusis]] |volume=27 |pages=65–68 |doi=10.1051/analusis:1999108}}</ref>

Revision as of 11:16, 25 January 2018

Uranium in the environment refers to the science of the sources, environmental behaviour, and effects of

munitions is controversial because of questions about potential long-term health effects.[3][4]

Natural occurrence

Uranium ore

Uranium is a naturally occurring element found in low levels within all rock, soil, and water. This is the highest-numbered element to be found naturally in significant quantities on earth. According to the United Nations Scientific Committee on the Effects of Atomic Radiation the normal concentration of uranium in soil is 300 μg/kg to 11.7 mg/kg.[5]

It is considered to be more plentiful than antimony, beryllium, cadmium, gold, mercury, silver, or tungsten and is about as abundant as tin, arsenic or molybdenum. It is found in many minerals including uraninite (most common uranium ore), autunite, uranophane, torbernite, and coffinite. Significant concentrations of uranium occur in some substances such as phosphate rock deposits, and minerals such as lignite, and monazite sands in uranium-rich ores (it is recovered commercially from these sources).

liter of seawater.[6] as uranium(VI) forms soluble carbonate
complexes. The extraction of uranium from seawater has been considered as a means of obtaining the element.

Sources of uranium

Mining and milling

The radiation hazards of uranium mining and milling were not appreciated in the early years, resulting in workers exposed to high levels of radiation. Conventional uranium ore treatment mills create radioactive waste in the form of tailings, which contain uranium, radium, and polonium. Consequently, uranium mining results in "the unavoidable radioactive contamination of the environment by solid, liquid and gaseous wastes".[7] Inhalation of radon gas caused sharp increases in lung cancers among underground uranium miners employed in the 1940s and 1950s.[8]

In the 1940s and 1950s, uranium mill tailings were released with impunity into water sources, and the radium leached from these tailings contaminated thousands of miles of the Colorado River system. Between 1966 and 1971, thousands of homes and commercial buildings in the Colorado Plateau region were "found to contain anomalously high concentrations of radon, after being built on uranium tailings taken from piles under the authority of the Atomic Energy Commission".[9]

Metal

See also: Depleted uranium
DU penetrator from the PGU-14/B incendiary 30 mm round

Depleted uranium (DU) is useful because of its very high

projectiles
.

Uranium metal can disperse into the air and water, United Nations Environment Programme (UNEP) study says in part:

"The most important concern is the potential for future groundwater contamination by corroding penetrators (ammunition tips made out of DU). The munition tips recovered by the UNEP team had already decreased in mass by 10-15% in this way. This rapid corrosion speed underlines the importance of monitoring the water quality at the DU sites on an annual basis."[10]

Combustion

Studies of depleted uranium aerosol exposure suggest that uranium combustion product particles would quickly settle out of the air,[11] and thus could not affect populations more than a few kilometres from target areas.[12]

The U.S. has admitted that there have been over 100 "friendly fire" incidents in which members of the U.S. military have been struck by DU munitions, and that an unknown number have been exposed to DU via inhalation of combustion products from burning DU munitions.

Corrosion

It has been reported that the corrosion of uranium in a silica rich aqueous solution forms both uranium dioxide and uranium trioxide.[13]

In pure water, schoepite {(UO2)8O2(OH)12.12(H2O)} is formed [14][failed verification] in the first week and then after four months studtite {(UO2)O2·4(H2O)} was formed.

Uranium metal reacts with water to form hydrogen gas, this reaction forms uranium dioxide and 2% to 9% uranium hydride. It is important to note that the rate of corrosion due to water is far greater than that caused by oxygen at temperatures around 100 °C (212 °F). At pH values below 2 the corrosion rate at 100 °C goes down greatly, while as pH values go from 7 upwards the corrosion rate declines. Gamma irradiation has little effect on the corrosion rate.[15]

Oxygen gas inhibits the corrosion of uranium by water. .[16]

Nuclear waste

Spent

fission products) even more slowly than borosilicate glass when in contact with water.[17]

Note that while the vast majority of the uranium is removed by

minor actinides and the residual plutonium
in the waste the concentration of uranium will increase on the waste. This will occur on a time scale of hundreds and thousands of years.

Health effects

aromatic disulfonic acid
. It is an alternative to bicarbonate which has already been tested in animals.

Soluble uranium salts are

toxic, though less so than those of other heavy metals such as lead or mercury. The organ which is most affected is the kidney. Soluble uranium salts are readily excreted in the urine, although some accumulation in the kidneys does occur in the case of chronic exposure. The World Health Organization has established a daily "tolerated intake" of soluble uranium salts for the general public of 0.5 μg/kg body weight (or 35 μg for a 70 kg adult): exposure at this level is not thought to lead to any significant kidney damage.[18][failed verification
]

The antidote for uranium in humans is bicarbonate, which is used because uranium (VI) forms complexes with carbonate. An alternative is to use tiron (sodium 4,5-dihydroxybenzene-1,3-disulfonate).[19]

Humans

Further information: Uranium § Human exposure

Cancer

In 1950, the US Public Health service began a comprehensive study of uranium miners, leading to the first publication of a statistical correlation between cancer and uranium mining, released in 1962.[20] The federal government eventually regulated the standard amount of radon in mines, setting the level at 0.3 WL on January 1, 1969.[21]

Out of 69 69 present and former uranium milling sites in 12 states, 24 have been abandoned, and are the responsibility of the

Sequoyah Corporation Fuels Release in Oklahoma.[23]

In 1990,

amendments passed in 2000 to address criticisms with the original act.[20]

Depleted uranium exposure

See also: Depleted uranium
Sites in Kosovo and southern Central Serbia where NATO aviation used depleted uranium munitions during 1999 bombing

The use of depleted uranium (DU) in

toxic metal.[2] The aerosol produced during impact and combustion of depleted uranium munitions can potentially contaminate wide areas around the impact sites leading to possible inhalation by human beings.[24] During a three-week period of conflict in 2003 in Iraq, 1,000 to 2,000 tonnes of DU munitions were used.[25]

The actual acute and chronic toxicity of DU is also a point of medical controversy. Multiple studies using cultured cells and laboratory rodents suggest the possibility of

neurological effects from chronic exposure.[3]
A 2005 epidemiology review concluded: "In aggregate the human epidemiological evidence is consistent with increased risk of birth defects in offspring of persons exposed to DU."[26] The World Health Organization, the directing and coordinating authority for health within the United Nations which is responsible for setting health research norms and standards, providing technical support to countries and monitoring and assessing health trends,[27] states that no risk of reproductive, developmental, or carcinogenic effects have been reported in humans due to DU exposure.[28][29] This report has been criticized by Dr. Keith Baverstock for not including possible long-term effects of DU on human body.[30]

Birth defects

Most scientific studies have found no link between uranium and birth defects, but some claim statistical correlations between soldiers exposed to DU, and those who were not, concerning reproductive abnormalities.

One study concluded that epidemiological evidence is consistent with an increased risk of birth defects in the offspring of persons exposed to DU.[26] Environmental groups and others have expressed concern about the health effects of depleted uranium,[31] and there is some debate over the matter. Some people have raised concerns about the use of this material, particularly in munitions, because of its mutagenicity,[32] teratogenicity in mice,[33][34] and neurotoxicity,[35] and its suspected carcinogenic potential. Additional concerns address unexploded DU munitions leeching into groundwater over time.[36]

Several sources have attributed the increase in the rate of birth defects in the children of Gulf War veterans and in Iraqis to depleted uranium inhalation exposure,[34][37] A 2001 study of 15,000 February 1991 U.S. Gulf War combat veterans and 15,000 control veterans found that the Gulf War veterans were 1.8 (fathers) to 2.8 (mothers) times more likely to have children with birth defects.[38] In a study of UK troops, "Overall, the risk of any malformation among pregnancies reported by men was 50% higher in Gulf War Veterans (GWV) compared with Non-GWVs". The conclusion of the study stated "We found no evidence for a link between paternal deployment to the Gulf war and increased risk of stillbirth, chromosomal malformations, or congenital syndromes. Associations were found between fathers' service in the Gulf war and increased risk of miscarriage and less well-defined malformations, but these findings need to be interpreted with caution as such outcomes are susceptible to recall bias. The finding of a possible relationship with renal anomalies requires further investigation. There was no evidence of an association between risk of miscarriage and mothers' service in the gulf."[39]

Animals

It has been reported that uranium has caused

teratogenic.[26][33][34]

Bacterial biochemistry

It has been shown that bacteria, and

U(IV) ion, hence stopping chemical leaching
.

Behavior in soil

It has been suggested that it is possible to form a reactive barrier by adding something to the soil which will cause the uranium to become fixed. One method of doing this is to use a mineral (

humic acids, this tends to fix the uranium in the soil.[46]

References

  1. ^ Georgia State University. "Biological Half Lives".
  2. ^
    PMID 15205046
    .
  3. ^
    PMID 17508699
    .
  4. ^
    doi:10.1098/rsif.2009.0300
    .
  5. ISBN 92-1-142200-0
    .
  6. ^ Isotopes of the Earth's Hydrosphere By V.I. Ferronsky, V.A. Polyakov, pg 399.
  7. ^ Benjamin K. Sovacool (2011). Contesting the Future of Nuclear Power: A Critical Global Assessment of Atomic Energy, World Scientific, p. 137.
  8. PMID 2746814
    . Retrieved 2007-08-09.
  9. ^ Benjamin K. Sovacool (2011). Contesting the Future of Nuclear Power: A Critical Global Assessment of Atomic Energy, World Scientific, p. 138.
  10. ^ "UNEP confirms low-level DU contamination". United Nations Environment Programme. March 22, 2002.
  11. ^ "Depleted uranium". Department of Defense. Archived from the original on June 14, 2006. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  12. PMID 12705453.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  13. PDF abstract). Goldschmidt Conference. Kurashiki, Japan.{{cite conference}}: CS1 maint: multiple names: authors list (link
    )
  14. ^ "Schoepite Mineral Data". Retrieved August 28, 2010.
  15. doi:10.1039/TF9666202513
    .
  16. doi:10.1039/TF9666202525
    .
  17. ^ B.E. Burakov, M.I Ojovan, W.E. Lee. Crystalline Materials for Actinide Immobilisation, Imperial College Press, London, 198 pp. (2010). "Archived copy". Archived from the original on 2012-03-09. Retrieved 2010-10-16. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)CS1 maint: archived copy as title (link)
  18. ^ "Focus: Depleted Uranium". International Atomic Energy Agency. Archived from the original on March 18, 2010. Retrieved August 28, 2010. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  19. doi:10.1051/analusis:1999108.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  20. ^ a b Dawson, Susan E, and Gary E Madsen. "Uranium Mine Workers, Atomic Downwinders, and the Radiation Exposure Compensation Act." In Half Lives & Half-Truths: Confronting the Radioactive Legacies of the Cold War, 117-143. Santa Fe: School For Advanced Research, 2007)
  21. ^ Brugge, Doug, Timothy Benally, and Esther Yazzie-Lewis. The Navajo People and Uranium Mining. Albuquerque : University of New Mexico Press, 2006.
  22. ^ Decommissioning of U.S. Uranium Production Facilities
  23. ^ Doug Brugge, et al, "The Sequoyah Corporation Fuels Release and the Church Rock Spill", American Journal of Public Health, September 2007, Vol., 97, No. 9, pp. 1595-1600.
  24. ^ Mitsakou C, Eleftheriadis K, Housiadas C, Lazaridis M Modeling of the dispersion of depleted uranium aerosol. 2003 Apr, Retrieved January 15, 2009
  25. ^ Paul Brown, Gulf troops face tests for cancer guardian.co.uk 25 April 2003, Retrieved February 3, 2009
  26. ^
    PMID 16124873. {{cite journal}}: Unknown parameter |lastauthoramp= ignored (|name-list-style= suggested) (help)CS1 maint: unflagged free DOI (link
    )
  27. ^ World Health Organization. "World Health Organization".
  28. ^ World Health Organization. "Depleted uranium". Archived from the original on August 15, 2012. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  29. ^ World Health Organization. "Depleted uranium".
  30. ^ Keith Baverstock. "Depleted Uranium Weapons" (PDF).
  31. ^ A. L. Kennedy (July 10, 2003). "Our gift to Iraq". The Guardian.
  32. PMID 16221956.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  33. ^
    PMID 12539863
    .
  34. ^
    PMID 11738513
    .
  35. PMID 15681127. {{cite journal}}: Unknown parameter |lastauthoramp= ignored (|name-list-style= suggested) (help
    )
  36. PMID 15571876.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  37. PMID 2366813. {{cite journal}}: Unknown parameter |lastauthoramp= ignored (|name-list-style= suggested) (help
    )
  38. PMID 11557183.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  39. PMID 15075150.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  40. PMID 7694141.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  41. PMID 16283518.{{cite journal}}: CS1 maint: multiple names: authors list (link)Closed access icon
  42. PMID 16124300.{{cite journal}}: CS1 maint: multiple names: authors list (link)Closed access icon
  43. PMID 14532040. {{cite journal}}: Cite uses deprecated parameter |authors= (help
    )
  44. PMID 25874721.{{cite journal}}: CS1 maint: unflagged free DOI (link
    )
  45. ^ Christopher C. Fuller, John R. Bargar & James A Davis (November 20, 2003). "Remediation of uranium-contaminated waterat Fry Canyon, Utah". Stanford University.
  46. ^ "Geochemistry" (PDF). Archived from the original (PDF) on December 12, 2004. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
Retrieved from "https://en.wikipedia.org/w/index.php?title=Uranium_in_the_environment&oldid=822267570"