Properties of Caesium
Caesium is a soft, alkali metal with an atomic number of 55. The metal appears as a silvery-gold metal and has similar physical and chemical properties as rubidium and potassium; moreover, caesium has a melting point of 28.4ºC, making it one of only five elemental metals that are liquid at room temperature. In addition to this, caesium is extremely reactive and pyrophoric - explosively reacting with water at -116ºC and igniting spontaneously in air. Because of its high reactivity, caesium is classified as a hazardous material and must be handled under inert gas, such as argon.
Caesium has a total of 39 isotopes ranging from mass numbers of 112 to 151. In nature, caesium exists only as a non-radioactive (or stable) isotope known as caesium-133 (Cs-133); however, there exist several caesium isotopes that are radioactive. The radioactive isotopes of caesium are formed during nuclear fission, in commercial applications such as the generation of electricity at nuclear power plants. The most important caesium isotopes in terms of their potential effects on human health are caesium-134 (Cs-134) and caesium-137 (Cs-137). Both Cs-137 and Cs-134 release beta radiation and gamma radiation. Beta radiation travels shorter distances and penetrates the skin and body tissues, while gamma radiation travels greater distances and penetrate the entire body. The radiation dose from these radionuclides can be classified as either external (if the radiation source is outside the body) or internal (if the radiation source is inside the body). Beta radiation emitted outside the body is normally of little health concern unless the radioactive material contacts the skin. Skin contact can allow the beta radiation to pass through the epidermis to live dermal tissue where it becomes a major contributor to the radiation dose to the skin. Beta and gamma radiation may induce tissue damage and disruption of cellular function.
The half-lives of Cs-134 and Cs-137 are approximately 2 years and 30 years, respectively. Because of the continual emission of radiation, people could be exposed to radiation from Cs-137 or Cs-134 released to the environment. High levels of Cs-134 and Cs-137 have been released to the environment from nuclear weapons testing and incidents such as the 1986 accident at the Chernobyl nuclear reactor in Ukraine. In these cases, cesium was one of many radionuclides present in the release. Once released into the environment, caesium-137 is subject to radioactive decay with the emission of beta particles and gamma radiation. Because of the chemical nature of caesium, it move easily throughout the environment, thus making caesium-137 difficult to cleanup.
The following video exhibits the initial cloud of caesium-137 over Europe immediately after the Chernobyl nuclear reactor explosion and helps validate the fact that caesium-137 will continue to affect individuals in the indicated regions because of Cs-137 30 year half life.
Caesium has a total of 39 isotopes ranging from mass numbers of 112 to 151. In nature, caesium exists only as a non-radioactive (or stable) isotope known as caesium-133 (Cs-133); however, there exist several caesium isotopes that are radioactive. The radioactive isotopes of caesium are formed during nuclear fission, in commercial applications such as the generation of electricity at nuclear power plants. The most important caesium isotopes in terms of their potential effects on human health are caesium-134 (Cs-134) and caesium-137 (Cs-137). Both Cs-137 and Cs-134 release beta radiation and gamma radiation. Beta radiation travels shorter distances and penetrates the skin and body tissues, while gamma radiation travels greater distances and penetrate the entire body. The radiation dose from these radionuclides can be classified as either external (if the radiation source is outside the body) or internal (if the radiation source is inside the body). Beta radiation emitted outside the body is normally of little health concern unless the radioactive material contacts the skin. Skin contact can allow the beta radiation to pass through the epidermis to live dermal tissue where it becomes a major contributor to the radiation dose to the skin. Beta and gamma radiation may induce tissue damage and disruption of cellular function.
The half-lives of Cs-134 and Cs-137 are approximately 2 years and 30 years, respectively. Because of the continual emission of radiation, people could be exposed to radiation from Cs-137 or Cs-134 released to the environment. High levels of Cs-134 and Cs-137 have been released to the environment from nuclear weapons testing and incidents such as the 1986 accident at the Chernobyl nuclear reactor in Ukraine. In these cases, cesium was one of many radionuclides present in the release. Once released into the environment, caesium-137 is subject to radioactive decay with the emission of beta particles and gamma radiation. Because of the chemical nature of caesium, it move easily throughout the environment, thus making caesium-137 difficult to cleanup.
The following video exhibits the initial cloud of caesium-137 over Europe immediately after the Chernobyl nuclear reactor explosion and helps validate the fact that caesium-137 will continue to affect individuals in the indicated regions because of Cs-137 30 year half life.
Health Effects of Caesium-137
Like all radionuclides, exposure to radiation from cesium-137 results in increased risk of cancer. Everyone is exposed to very small amounts of cesium-137 in soil and water as a result of atmospheric fallout. Exposure to waste materials, from contaminated sites, or from nuclear accidents can result in cancer risks much higher than typical environmental exposures.Caesium-137 fallout from the Chernobyl incident has been found to cause radiation-induced thyroid cancer. The 1986 Chernobyl nuclear reactor explosion subjected regions of Belarus, Ukraine, and Bryasnk to caesium-137 in addition to various isotopes of iodine - such as iodine-131. Due to the long half-life of caesium-137 (30 years), the environment of these regions were subjected to contamination, even to this day.
A 1972 Brazilian case study on the carcinogenicity of caesium-137 examined the health effects in humans exposed to caesium-137. In 1987, civilians in Goiania, Brazil, were accidentally exposed to caesium-137. External and internal exposures of humans to caesium-137 resulted in a wide variety of adverse health effects that range from nausea to death. In 1987, approximately 250 persons, including children, were exposed externally and internally to radiation from a scavenged medical source with an activity of 50.9 TBq of 137-CsCl. Numerous individuals exposed to caesium-137 displayed signs of acute radiation syndrome, such as nausea, vomiting, and diarrhea. A majority of the individuals with acute radiation syndrome developed bone marrow failure and four of those individuals died. Dermal injuries observed among the exposed individuals ranged from radiation dermatitis to severe radiation injuries resulting in amputation. Ocular and reproductive effects were also reported. Two incidents of external exposure to radiation from Cs-137 have demonstrated that serious adverse effects may also be expected when individuals are exposed only externally to high levels of radiation from Cs-137.
From this case study it has become evident that individuals are not likely to experience any health effects that could be related to stable cesium (Cs-133). Animals given very large doses of caesium compounds have shown changes in behavior, such as increased activity or decreased activity, but it is highly improbable that one would eat or drink large amounts of stable caesium to cause modifications in behavior. If one were to breathe, eat, drink, touch, or come in close proximity to large amounts of radioactive caesium-137, cells in the body could become damaged from the radiation due to gamma radiation emitted from decaying caesium-137, much like x-rays. Individuals subjected to large amounts of caesium-137 are likely experience similar effects if one were exposed to any other radionuclides; moreover, individuals may experience acute radiation syndrome, which includes such effects as nausea, vomiting, diarrhea, bleeding, coma, and even death. The effects of radioactive caesium are not exclusive to adults. Caesium-137 has been found to effect children in the same way as adults. Similar to adults, stable caesium, Cs-133, is not likely to have an affect on children's health; however, just like with any radionuclide, exposure to large amounts of radioactive caesium-137 will induce large amounts of gamma radiation that will damage vital cells and could culminate in random DNA indels and the manifestation of cancerous cells. Short exposure to extremely large amounts of radiation might cause nausea, vomiting, diarrhea, bleeding, coma, and even death - similar to symptoms experienced in adults. In addition, if babies were to be exposed to enough radiation while in their mother’s womb during the time when their nervous system is rapidly developing, they could experience changes in their brains that could result in changes in behavior or decreased mental abilities.
Although focused on the Fukushima incident, the following video further explains the dangers of caesium-137.
A 1972 Brazilian case study on the carcinogenicity of caesium-137 examined the health effects in humans exposed to caesium-137. In 1987, civilians in Goiania, Brazil, were accidentally exposed to caesium-137. External and internal exposures of humans to caesium-137 resulted in a wide variety of adverse health effects that range from nausea to death. In 1987, approximately 250 persons, including children, were exposed externally and internally to radiation from a scavenged medical source with an activity of 50.9 TBq of 137-CsCl. Numerous individuals exposed to caesium-137 displayed signs of acute radiation syndrome, such as nausea, vomiting, and diarrhea. A majority of the individuals with acute radiation syndrome developed bone marrow failure and four of those individuals died. Dermal injuries observed among the exposed individuals ranged from radiation dermatitis to severe radiation injuries resulting in amputation. Ocular and reproductive effects were also reported. Two incidents of external exposure to radiation from Cs-137 have demonstrated that serious adverse effects may also be expected when individuals are exposed only externally to high levels of radiation from Cs-137.
From this case study it has become evident that individuals are not likely to experience any health effects that could be related to stable cesium (Cs-133). Animals given very large doses of caesium compounds have shown changes in behavior, such as increased activity or decreased activity, but it is highly improbable that one would eat or drink large amounts of stable caesium to cause modifications in behavior. If one were to breathe, eat, drink, touch, or come in close proximity to large amounts of radioactive caesium-137, cells in the body could become damaged from the radiation due to gamma radiation emitted from decaying caesium-137, much like x-rays. Individuals subjected to large amounts of caesium-137 are likely experience similar effects if one were exposed to any other radionuclides; moreover, individuals may experience acute radiation syndrome, which includes such effects as nausea, vomiting, diarrhea, bleeding, coma, and even death. The effects of radioactive caesium are not exclusive to adults. Caesium-137 has been found to effect children in the same way as adults. Similar to adults, stable caesium, Cs-133, is not likely to have an affect on children's health; however, just like with any radionuclide, exposure to large amounts of radioactive caesium-137 will induce large amounts of gamma radiation that will damage vital cells and could culminate in random DNA indels and the manifestation of cancerous cells. Short exposure to extremely large amounts of radiation might cause nausea, vomiting, diarrhea, bleeding, coma, and even death - similar to symptoms experienced in adults. In addition, if babies were to be exposed to enough radiation while in their mother’s womb during the time when their nervous system is rapidly developing, they could experience changes in their brains that could result in changes in behavior or decreased mental abilities.
Although focused on the Fukushima incident, the following video further explains the dangers of caesium-137.
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"Ionising Radiation." GIOŚ - Główny Inspektorat Ochrony Środowiska - Ionizing Radiation. GIOŚ. Web. 9 Nov. 2014. <http://www.gios.gov.pl/stansrodowiska/gios/pokaz_artykul/en/front/stanwpolsce/srodowisko_i_zdrowie/promieniowanie_elektromagnetyczne_jonizujace>.