Fig. 1: Lake Karachay in Russia, one of the most radioactive sites in the world (Source: ecohubmap.com)
Radioactive pollution – also known as radioactive contamination, refers to the release of radioactive substances into the environment (Hussain & Keçili, 2020). Radionuclides, which emit beta particles and gamma rays during radioactive decay, are often the main culprit of radioactive pollution (Posudin, 2014). While most might reckon that the release of radionuclides predominantly occur during nuclear-related disasters, such as the use of nuclear weapons or nuclear power plant accidents, the presence of radionuclides—and by extension, the sources of radiation—are rather commonplace as shown in the table below:
Fig. 2: Sources of radiation exposure (Source: Qiao & Nielsen, 2019)
To further illustrate this, this blog article will expand on the two categories of radionuclides, as well as the sources and impacts of being exposed to radionuclides.
Naturally occurring radionuclides
Naturally occurring radionuclides are often found in environmental matrices such as soils, water, and air (Ojovan & Lee, 2005). Apart from these sources, phenomena such as volcanic activity (Perkins, 2019) also emit radioactive particles into the environment. In a nutshell, this group of radionuclides consists of primordial radioactive elements in the earth’s crust, their radioactive decay products, and radionuclides produced by cosmic-radiation interactions (National Academic Press (US), 1999). Among the many naturally occurring radionuclides is a particular radionuclide that has garnered increasing scrutiny due to its vast negative impacts – radon.
Exposure to radon (mostly 222Rn)—despite being a naturally occurring radionuclide—and its decay products, has raised public health concerns due to its high prevalence in indoor spaces and carcinogenic properties (World Health Organisation, 2023). To elaborate, Yousef and Zimami (2019) posit that exposure to radon makes up more than 70% of the total annual radioactive dose received by people, with radon exposure contributing to approximately half of the total effective dose equivalent received from natural and anthropogenic radioactivity.
Fig. 3: Sources of radon exposure (Source: International Atomic Energy Agency [IAEA], 2022)
The release of anthropogenic radionuclides largely stems from radioactive waste and contamination, which are often resultant of the development of nuclear power, nuclear accidents, and the operation of nuclear power plants (Qiao & Nielsen, 2019). To date, the majority of radioactivity stems from high-level waste and spent nuclear fuel, with nuclear accidents contributing to the highest amount of radioactive emissions (Hu et al., 2010).
The prevalence of anthropogenic radionuclides can also bring forth radioactive transfer through food chains due to the contamination of soils and water sources (IAEA, 2009), in which the radionuclides then transfer to cultivated crops. This phenomenon has been attributed to the deposition of radioactive fallout due to rampant nuclear weapons testing, which resulted in the dispersal of radioactive gases and particles (Centres for Disease Control and Prevention [CDC], 2014). Exposure to radioactive fallout can manifest in several ways:
Fig. 4: Ways in which people were exposed to radiation. (Source: CDC, 2014)
Nuclear accidents, such as the Chernobyl nuclear plant disaster, can also give contribute to significant deposition of radionuclides which can ultimately result in the radioactive contamination of food as well (Bundesamt für Strahlenschutz, 2022).
As such, while such forms of radiation exposure may not be as intense as those compared to nuclear disasters, the prolonged inhalation and consumption of radiation through contaminated air and food still remain a cause for concern. The following blog posts will dive deeper into the impacts of radioactive pollution, and will also touch on several case studies related nuclear disasters.
References
Barkhudarov, R. M., Knizhnikov, V. A., Novikova, N. Y., & Petukhova, E. V. (1988). Effect of Local Conditions on Coefficient of Radionuclide Transfer Through Food Chains. In J. H. Harley, G. D. Schmidt, & G. Silini (Eds.), Radionuclides in the Food Chain (pp. 133–135). Springer. https://doi.org/10.1007/978-1-4471-1610-3_11
HotSpot before and after: Lake Karachay in the Russian Federation filled with radioactive waste is the cause of cancer. (n.d.). Retrieved January 26, 2023, from https://www.ecohubmap.com/hot-spot/lake-karachay-become-the-most-polluted-spot-on-earth/5g4uyml7kr620m
Hu, Q.-H., Weng, J.-Q., & Wang, J.-S. (2010). Sources of anthropogenic radionuclides in the environment: A review. Journal of Environmental Radioactivity, 101(6), 426–437. https://doi.org/10.1016/j.jenvrad.2008.08.004
Hussain, C. M., & Keçili, R. (2020). Chapter 1—Environmental pollution and environmental analysis. In C. M. Hussain & R. Keçili (Eds.), Modern Environmental Analysis Techniques for Pollutants (pp. 1–36). Elsevier. https://doi.org/10.1016/B978-0-12-816934-6.00001-1
Materials, N. R. C. (US) C. on E. of E. G. for E. to N. O. R. (1999). Natural Radioactivity and Radiation. In Evaluation of Guidelines for Exposures to Technologically Enhanced Naturally Occurring Radioactive Materials. National Academies Press (US). https://www.ncbi.nlm.nih.gov/books/NBK230654/
Ojovan, M. I., & Lee, W. E. (2005). Chapter 5—Naturally Occurring Radionuclides. In M. I. Ojovan & W. E. Lee (Eds.), An Introduction to Nuclear Waste Immobilisation (pp. 43–52). Elsevier. https://doi.org/10.1016/B978-008044462-8/50007-7
Posudin, Y. (2014). Chapter 36—Radioactive Pollution. (2014). In Methods of Measuring Environmental Parameters (pp. 380–384). John Wiley & Sons, Ltd. https://doi.org/10.1002/9781118914236.ch36
Radioactive Fallout from Global Weapons Testing: Home | CDC RSB. (2022, December 23). https://www.cdc.gov/nceh/radiation/fallout/rf-gwt_home.htm
Radon. (2023, January 23). Retrieved January 25, 2023, from https://www.who.int/news-room/fact-sheets/detail/radon-and-health
Tarakanov, V. (2022, June 1). What is Radon and How are We Exposed to It? [Text]. IAEA. https://www.iaea.org/newscenter/news/what-is-radon-and-how-are-we-exposed-to-it
What radionuclides can be found in food? (2022, April 1). Federal Office for Radiation Protection. Retrieved January 26, 2023, from https://www.bfs.de/EN/topics/ion/environment/foodstuffs/introduction/introduction_node.html
Yousef, A. M. M., & Zimami, K. (2019). Indoor radon levels, influencing factors and annual effective doses in dwellings of Al-Kharj City, Saudi Arabia. Journal of Radiation Research and Applied Sciences, 12(1), 460–467. https://doi.org/10.1080/16878507.2019.1709727