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Radionuclides in water *
Published in Jamie Bartram, Rachel Baum, Peter A. Coclanis, David M. Gute, David Kay, Stéphanie McFadyen, Katherine Pond, William Robertson, Michael J. Rouse, Routledge Handbook of Water and Health, 2015
Radium has four naturally occurring isotopes including radium-228, radium-226, radium-224, and radium-223. The most common radium isotope, radium-226 (1,600 year radioactive half-life, emits α-particles and gamma rays) is formed in the uranium-238 decay series. Radium-228 (5.75 year half-life, β-emitter) and radium-224 (3.6 day half-life, α-emitter) are both decay products in the thorium-232 decay series. Radium-223 (11.4 day half-life, α-emitter) is formed in the uranium-235 series. Because radium-224 and radium-223 have relatively short radioactive half-lives and lower relative abundance as compared to radium-226 and radium-228, they are considered a lower health risk.
Radionuclide Sources
Published in Michael Pöschl, Leo M. L. Nollet, Radionuclide Concentrations in Food and the Environment, 2006
Jeffrey S. Gaffney, Nancy A. Marley
The uranium isotopes are all radioactive, and their decay produces a number of secondary radioactive elements that continue to decay until they reach stable nuclei. This decay chain of radionuclides is commonly referred to as the uranium decay series. Similarly thorium, another primordial isotope with a long half-life, also has a decay series that leads to the formation of numerous naturally occurring secondary radionuclides. Thus the key primordial radionuclides of uranium and thorium decay to many other radioactive isotopes that occur in the environment at different levels of abundance, depending on their own decay rates and those of their parents. Figure 2.1 and Figure 2.2 show the decay schemes for primordial 238U and 232Th, respectively. Figure 2.3 shows the decay processes for 235U. Only the major pathways are shown in these figures, with the significant γ emitters highlighted in bold type. More detailed information on the isotopic decay processes, including minor pathways, can be obtained from the Table of Isotopes [5–7].
Dictionary
Published in Mario P. Iturralde, Dictionary and Handbook of Nuclear Medicine and Clinical Imaging, 1990
Decay series. Synonym for decay chain. A series of radioactive decompositions in which radioactive daughters are produced; these radioactive daughters then become parents by producing radioactive daughters of their own.
Radiological risk assessment of the Hunters Point Naval Shipyard (HPNS)
Published in Critical Reviews in Toxicology, 2022
Dennis J. Paustenbach, Robert D. Gibbons
U-235 has a radioactive half-life of 7 × 108 years and is a naturally occurring radionuclide. U-235 accounts for 0.72 wt% of natural uranium with the remaining fractions consisting of U-238 at 99.27 wt% and U-234 at 0.006 wt%. Natural uranium is present in low amounts in rocks, soil, water, plants, and animals. Uranium and its decay products contribute to low levels of natural background radiation in the environment. U-235 transitions by alpha decay. Its decay products emit alpha, beta, and gamma radiation in various combinations depending upon which decay product of the U-235 decay series is evaluated. U-235 is primarily an internal radiation hazard if ingested or inhaled (ICRP 2008; Johnson et al. 2012). Studies of the chemical and physical characteristics of U-235 were carried out at HPNS due to its important role in nuclear fuel (USN 2004). Such studies included the chemical separation of U-235 samples irradiated at Lawrence Livermore National Laboratory, and animal research was also conducted to evaluate potential health effects from exposure to U-235, particularly highly enriched uranium in U-235. The potential for the presence of U-235 contamination at on-site laboratories was a primary reason it was identified as an ROC at HPNS (USN 2004). U-238 was not included as an ROC since results of the site investigations did not identify concentrations above risk screening criteria used by the USEPA and the Navy, and the majority of sampling results during site investigations were not statistically different from background.
Distribution of 210Po in spice plants cultivated by conventional farming
Published in International Journal of Radiation Biology, 2022
Radioisotopes are the main source of ionizing radiation that exists in all ground formations. Some exist naturally and a few other are manmade. Natural radioisotopes, in the decay series of 238U, 232Th and singly occurring 40K, are the main contributors to natural radiation exposure to human beings. Human beings are exposed externally and internally to ionizing radiation based on presence of radioisotopes. External exposure depends on concentrations of various radioisotopes present in soil and building materials, while internal exposure to human beings depends on concentration of radioisotopes in air and food materials. Main routes through which radioisotopes enter human body are through inhalation and ingestion. Radiation dose received through ingestion depends on concentration of radioisotopes in various food materials consumed by human beings. Studies on concentration of various isotopes in different food materials are important for estimation of ingestion dose received by the general public. Among naturally existing radioisotopes, alpha emitters are considered important due to their types of radiation emissions and magnitude of ingestion doses delivered to human beings. The most important naturally occurring alpha emitter which is distributed widely in the environment is 210Po, a daughter of 210Pb in the 238U series and its radiotoxicity is comparable with that of 239Pu. It has been reported that 210Po contributes to about 7% of effective dose due to ingestion of food materials (UNSCEAR 1988). Human beings consume food materials mainly from plant products and animal origins. Various parts of plants such as leaves, seeds, stems, fruits and tubers are consumed by human beings as food in large quantities.
Investigation of Radon Sources, Health Hazard and Risks assessment for children using analytical and geospatial techniques in District Bannu (Pakistan)
Published in International Journal of Radiation Biology, 2022
Huma Shakoor, Noor Jehan, Sardar Khan, Nimat Ullah Khattak
In the early 1900s, Radon (Rn) was detected by a German scientist, Dorn. 219 Rn (actinon), 220Rn (thoron), and 222Rn are three naturally occurring isotopes of Rn (Al-Awadi and Khan 2019). It is a natural radioactive gas which is produced from the Radioactive decay of Radium (226Ra), which in turn is the decay product of Uranium (238U) Radioactive decay series (Partington 1957). Rn is a chemically inert gas without any color, odor or taste. Its nucleus is rich of neutron concentration due to which it becomes the densest Radioactive in nature (Goff and Becker 2010). It decays into Rn progenies by releasing particularly alpha particles that on inhalation or ingestion can pose great threat to a human's life (Alter and Oswald 1988). Transportation of Rn in soil is a mechanical flow of air and water (Chauhan et al. 2008). The bioaccumulation of Rn occurs in the lungs at higher concentration and at lesser degree other organ are affected through Rn gas dissolved in blood (Auvinen et al. 1996). Stomach is the organ which receives the highest Rn dose, about the total of 90% dose (Kendall and Smith 2002). Due to the Radioactive and hazardous effects high concentration of Rn in indoor environment and drinking water poses a major threat to human health (National Research Council 1999; Leenhouts and Brugmans 2001; Keramati et al. 2018). Inhalation and ingestion are the two main ways by which human are exposed to Rn. Lung cancer due to the inhalation of Rn gas has got attention over the past few decades (Lubin 1994; Al-Awadi and Khan 2019). Lung cancer in late 1980s in the general population has been attributed to environmental Rn exposure in dwellings (Samet and Eradze 2000; Alberg and Samet 2003). The World Health Organization declared Rn as the second leading cause of lung cancer after tobacco smoke (Samet and Eradze 2000; Alina et al. 2012). When Rn gas is inhaled or ingested it dissolves in the body fat and its progeny moves within the human body and reaches the bone marrow (Alberg and Samet 2003). The accumulated dose of Rn in adult body is high, and gives way to the development of leukemia (Sandler et al. 2006). Rn and its progenies also produce melanoma and some childhood cancer (BEIR V 1990; National Research Council 1999). In the sampling areas, households obtained drinking water from tube wells, dug wells, bore wells, but in spite of this the exposure to Rn occurs primarily through inhalation.