Radionuclides in water *
Jamie Bartram, Rachel Baum, Peter A. Coclanis, David M. Gute, David Kay, Stéphanie McFadyen, Katherine Pond, William Robertson, Michael J. Rouse in Routledge Handbook of Water and Health, 2015
Cesium-137 is an anthropogenic radionuclide, with a 30 year half-life, produced during nuclear fission (i.e., the splitting of a nucleus into at least two other nuclei) of various isotopes of uranium, plutonium, and thorium. Cesium-137 decays by β decay that is shortly followed by the emission of a γ ray from its short lived decay product, barium-137m (the “m” indicates it is a metastable nuclear isomer that decays very quickly). Two other isotopes of cesium, cesium-135 and cesium-134, are often considered less of a health concern because of their decay characteristics. For example, cesium-135, a β emitter, with a half-life of 2.3 million years has very low specific activity (i.e., number of decays per unit mass or volume). Cesium-134, a β emitter, has a half-life of 2.1 years so does not persist in the environment as long as cesium-137. However, determining cesium-137/cesium-134 ratios may help to identify the source and age of cesium in water.
A Series of Unfortunate Events
Alan Perkins in Life and Death Rays, 2021
The total release of radioactive substances was considered to be greater than 14 exabecquerels (EBq, 14 × 1018 Bq), which included 1.8 EBq of iodine-131, 0.085 EBq of caesium-137 and other caesium radionuclides, 0.01EBq of strontium-90 and 0.003 EBq of plutonium radionuclides. The dispersal of iodine-131 presented an immediate problem to the local population. All 45,000 residents of the power plant town of Pripyat were evacuated on April 27. By May 14, around 116,000 people who had been living within a 30-kilometre radius had been evacuated and relocated. About 1,000 of these residents returned unofficially to live in the contaminated zone preferring to live in their own homes despite the health risks. Most of those evacuated individuals received radiation doses of less than 50 mSv, although a few received 100 mSv or more. Large areas of Europe were affected and an area of more than 200,000 square kilometres was contaminated with caesium-137. The three most affected countries were Belarus, the Russian Federation and Ukraine, but the contamination affected countries throughout Europe. After the initial period, caesium-137 became the nuclide of greatest radiological importance. Ground deposition was strongly influenced by the prevailing winds and rainfall, but the end result was that sheep in highland areas as far away as Wales had consumed grass contaminated with caesium-137 and farmers were prohibited from selling their lamb at food markets for many weeks after the incident.
Cervical cancer
Pat Price, Karol Sikora in Treatment of Cancer, 2014
There is an ongoing debate about the optimal schedule for intrauterine brachytherapy.49 Low dose rate (LDR) systems with Caesium-137 were radiobiologically ideal as they allowed ongoing repair of radiation damage to normal tissues. However, these machines are no longer manufactured and are being replaced by high dose rate (HDR) systems delivering rates in excess of 1 Gy/min, and the most common source is Iridium-192. The short treatment time allows more geometrical stability of the applicator during treatment and more rapid patient throughput, but there is considerably less time for repair of radiation damage. Therefore, such treatments are fractionated over several days and the dose is adjusted for this difference in dose rate. Pulsed dose rate brachytherapy (PDR) uses an HDR source but delivers multiple small fractions over 2 days for a single insertion to reproduce LDR radiobiology.50 To be able to compare outcomes for these different dose rates and fractionation regimens it is now standard to report 2 Gy equivalent (EQD2) total doses.
Consequences of a large-scale nuclear accident and guidelines for evacuation: a cost-effectiveness analysis
Published in International Journal of Radiation Biology, 2020
Moshe Yanovskiy, Ori Nissim Levi, Yair Y. Shaki, Yehoshua Socol
Radiation contamination decreases with time due to radioactive decay. In case of NPP accident, many radionuclides are released. The longest-living relevant radionuclide—cesium-137 (Cs-137)—has a half-life of 30 years; thus, its radioactivity decreases rather slowly: 50% of the initial level after 30 years, 25% of the initial level after 60 years and so on. However, many short-living isotopes are also released, so the initial radiation level decreases rather rapidly during the first year. There is also another mechanism of radiation rate decrease—the migration of radionuclides from the contaminated surface due to rain, wind, road traffic etc. The data for Chernobyl and Fukushima is fairly consistent (Balonov 2016; IRSN 2016; Zoriy et al. 2016; WNA 2018b) and shown in Figure 1. As a result, radiation dose absorbed in 10 years is only twice higher than the first-year dose, and the lifetime dose is approximately equal to three first-year doses (UNSCEAR 2013, p. 209). Although this fact is well known, it is not always considered in the radiation-protection context. One year after the accident and onwards the dose-rate R(t) can be approximately described by R(t) = R(0)/(1 + 0.75 × t) where t – time in years. This approximation is illustrated in Figure 1. Table 1 summarizes doses absorbed during different periods of time after the accident relative to the dose absorbed during the first 12 months.
A review of the impact on the ecosystem after ionizing irradiation: wildlife population
Published in International Journal of Radiation Biology, 2022
Georgetta Cannon, Juliann G. Kiang
Twenty-one years later after the Chernobyl power plant explosion, various isotopes of plutonium, strontium-90, americium-241, and cesium-137 were still detected at high levels causing adverse biological effects across the nearby areas (Voitsekhovych et al. 2007). Wildlife continued to be exposed to substantial radiation doses after humans were evacuated from these areas. The half-life of cesium-137 is approximately 30 years and it decays by β emission to a metastable isomer of barium-137. The half-life of barium-137 isomer is 2 minutes. Subsequently, the metastable isomer emits γ radiation and becomes ground state barium (Baum et al. 2002). Food or water contaminated with cesium-137 that are ingested lead to internal β and γ radiation doses in addition to external radiation doses. The half-life of cesium-134 is about 2 years. Cesium-134 emits β particles. The half-life of strontium-90 is approximately 29 years. Strontium-90 emits pure β radiation. Most of the plutonium isotopes emit α particles, which are ionizing and harmful, but have a short penetration distance. The half-life of plutonium-241 is approximately 14 years. It emits β radiation to become americium-241. The half-life of americium-241 is 432 years, and it emits α particles to become neptunium-237, with a by-product of γ emissions (Baum et al. 2002). This is the composition of radiation released and retained in the soil, water and air across the Chernobyl landscape. In addition to external radiation exposure, ingestion of contaminated food and water by wildlife occurred from the beginning of the disaster and continues to the present.
The Goiânia incident, the semiotics of danger, and the next 10,000 years
Published in Clinical Toxicology, 2023
Joseph Clemons, Adam Blumenberg
The Goiânia incident involved less than 100 g of pure cesium-137, which has a physical half-life of 30 years. Nuclear weapons development, including the Manhattan Project, has generated tremendous quantities of radioactive waste. Cleanup of the Hanford Washington site alone, which produced the plutonium for the “Fat Man” atomic bomb, includes 20 tons of plutonium, construction material from hundreds of contaminated buildings, 2,300 tons of spent nuclear fuel rods, thousands of tons of contaminated soil, and millions of gallons of highly contaminated waste water [21]. The radioactive waste will be dangerous for over 100,000 years. This material is intended to be stored in the Waste Isolation Pilot Plant, an underground facility in New Mexico hundreds of meters below ground (Figure 5) [22]. Every nation that utilizes radioactive material shares the problem of long-term disposal of these substances.
Related Knowledge Centers
- Beta Decay
- Caesium
- Chemical Compound
- Nuclear Fission
- Radioactive Decay
- Nuclear Fission Product
- Spontaneous Fission
- Nuclear Fallout
- Salt
- Half-Life