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| Fig. 1: Open-pit Uranium mine in Namibia. (Source: Wikimedia Commons) |
Uranium is a potent source of energy used by many developed nations to power the growing energy demand of their people. [1] In an effort to fuel this demand, many countries like Canada, Australia, and Kazakhstan are responsible for sourcing much of the world's uranium demand through uranium mines. [1] There are a few classes of uranium mining styles commonly used for uranium mining: open-pit mining, underground mining, in-situ mining (Fig. 1). Following the extraction of uranium ore, it will typically go through a milling process, where the uranium ore is converted into a usable form: yellow cake. [1] Production of energy from uranium is more efficient per kilogram than fossil fuels like coal, per
| kg coal kg U-235 |
= | 230 × 106 eV atom-1
× 1.602 × 10-19 J eV-1 0.235 kg mole-1 × 3.8 × 107 J kg-1 | |
| × 6.022 × 1023 atoms mole-1 | |||
| = | 2.5 × 106 |
Thus approximately 2.54 million times more energy is released via fission than by combusting an equivalent amount mass of coal. [2] Despite this, there are other serious impacts associated with uranium production and mining.
Uranium mines and exposure can impact environmental health through a variety of different ways. One of the primary avenues of environmental uranium contamination is uranium air pollution. [3] Tracy and Meyerhof found that in a 2 kilometer area surrounding a uranium refinery there was 200-times as much uranium particulate measured in the air than in surrounding regions. [3] Once in the air, airborne uranium has the potential to deposit and subsequently contaminate other areas of the environment such as vegetation. [3] A study found that uranium concentrations were 75-times higher in surrounding vegetation near a uranium processing plant. [1] Another prominent effect of uranium mining is acid mine drainage, a pollutant and chemical-rich type of wastewater that is a byproduct of uranium mining and processing. [4] Ferrari et al. found that effluent runoff from a local uranium mine had led to the Antas reservoir exceeding the legal limits for chemicals like uranium, sulfate, aluminum, fluoride, and manganese. [4]
From the above examples, it is clear that uranium mining has a measurable impact on the environmental health of surrounding regions. How does this translate to human health? Uranium naturally occurs in human bodies at low levels (90 μg) and is primarily absorbed through the body via inhalation and ingestion, leaving those that are in close proximity to uranium-contaminated areas at risk, through the previously discussed pollution pathways. [5] In the human body, uranium is processed primarily by the kidneys and excreted via urination; this makes urine tests a valuable assessment of uranium exposure to a group of individuals. Hao et al. found that uranium concentrations in urine for those living in a Mongolian uranium mining area is over 4-times as much as those living in a control region. [5,6] If the exposed uranium amount is significantly higher than the amount that can be excreted via measures like urine, it will lead to accumulation in the liver, bones, and kidney and subsequent toxicity (i.e. oxidative stress, cytotoxicity, genotoxicity, etc.). [5]
The health effect of human uranium exposure can be most evidently seen in research studies on the health of workers and miners in the uranium industry. [7-9] Multiple studies have focused on Kazakhstan, one of the largest uranium producers internationally. [7-9] For example, Saifulina et al. studied health conditions of those living in a Kazakhstan uranium mining province compared to that of a control and found those living in the uranium producing province to have higher prevalence of genitourinary, circulatory, and respiratory diseases. [8] Similarly, Toksobayeva et al. discovered that workers in North Kazakhstan uranium mines had a higher frequency of chromosomal aberrations compared to a control group, a relationship that grows with time spent working in uranium mines, highlighting the genotoxicity of prolonged uranium exposure. [7,9]
© Justin Shen. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] R. R. Srivastava, P. Pathak, and M. Perween, "Environmental and Health Impact Due to Uranium Mining," in Uranium in Plants and the Environment, ed by D. K. Gupta and W. Clemens (Springer, 2019).
[2] M. Filonchyk and M. P. Peterson, "An Integrated Analysis of Air Pollution From US Coal-Fired Power Plants," Geosci. Front. 14, 101498 (2023).
[3] B. L. Tracy and D. P. Meyerhof, "Uranium Concentrations in Air Near a Canadian Uranium Refinery," Atmos. Environ. 21, 165 (1987).
[4] C. R. Ferrari et al., "Effects of the Discharge of Uranium Mining Effluents on the Water Quality of the Reservoir: An Integrative Chemical and Ecotoxicological Assessment," Sci. Rep. 7, 13919 (2017).
[5] M. Ma et al., "Emerging Health Risks and Underlying Toxicological Mechanisms of Uranium Contamination: Lessons From the Past Two Decades," Environ. Int. 145, 106107 (2020).
[6] Z. Hao et al., "Levels of Rare Earth Elements, Heavy Metals and Uranium in a Population Living in Baiyun Obo, Inner Mongolia, China: A Pilot Study," Chemosphere128, 161 (2015).
[7] R. I. Bersimbaev and O. Bulgakova, "The Health Effects of Radon and Uranium on the Population of Kazakhstan," Genes Environ. 37, 18 (2015).
[8] E. Saifulina et al., "Epidemiology of Somatic Diseases and Risk Factors in the Population Living in the Zone of Influence of Uranium Mining Enterprises of Kazakhstan: A Pilot Study," Healthcare 11, 804 (2023).
[9] G. A. Toksobayeva, A. A. Kakabayev, and R. I. Bersimbaev, "Investigation of Chromosomal Aberration Frequencies and Glutathione-S-Transferase M1 and T1 Genes in Workers Occupationally Exposed to Uranium in Northern Kazakhstan," in Rapid Diagnosis in Populations at Risk From Radiation and Chemicals, ed. by A. Celulsak-Wasilewska, A. N. Osipov, and F. Darroudi (IOS Press, 2010).
