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Water Pollutants and Water Pollution
Published in Stanley E. Manahan, Environmental Chemistry, 2022
Radionuclides differ from other nuclei in that they emit ionizing radiation—alpha particles, beta particles, and gamma rays. The most massive of these emissions is the alpha particle, a helium nucleus of atomic mass 4, consisting of two neutrons and two protons. The symbol for an alpha particle is shown in Reaction 6.12 for the nuclear reaction for the radioactive decay of uranium-238: U92238→Th90234+α24←Symbolforalphaparticle
Classification and Sources of Pollutants
Published in Mary K. Theodore, Louis Theodore, Introduction to Environmental Management, 2021
Mary K. Theodore, Louis Theodore
Radionuclides are radioactive isotopes that emit radiation as they decay. The most significant radionuclides in drinking water are radium, uranium, and radon, all of which occur naturally in nature. While radium and uranium enter the body by ingestion, radon is usually inhaled after being released into the air during showers, baths, and other activities, such as washing clothes or dishes. Radionuclides in drinking water occur primarily in those systems that use groundwater. Naturally occurring radionuclides seldom are found in surface waters (such as rivers, lakes, and streams).
A Review on Radionuclide Toxicity
Published in Debasis Bagchi, Manashi Bagchi, Metal Toxicology Handbook, 2020
Fco. Javier Guillén Gerada, José Ángel Corbacho Merino
A radionuclide is an isotope of an element, which is unstable. It decays with time, losing its excess energy, into another isotope of the same element or transforms into another element. The decay probability of a radionuclide, λ, is a physical property unique of that radionuclide. This probability is expressed in terms of half-live, T½. The half-life of a radionuclide is the amount of time to be elapsed so that the number of radionuclides is halved. Different radionuclides of the same element have different half-lives. The activity of a radionuclide, A, is its decay rate, and it is expressed by the following equation: A=λNλ=ln2T12
Natural radioactivity in European drinking water: A review
Published in Critical Reviews in Environmental Science and Technology, 2023
Marta Gómez, Siiri Suursoo, Nicolas Martin-Sanchez, Taavi Vaasma, Maria Leier
More than three quarters of the dose from ionizing radiation is caused by natural radiation sources (CSN, 2015). Naturally occurring radionuclides can be found in air, water, soil and living organisms. Some rocks and soil emit radiation because they contain uranium and its daughter nuclides, thorium and its daughter nuclides and natural potassium, the so-called primordial radionuclides (Suárez et al., 2000). But the radionuclide content is not the same for all soils, for example granitic and shale formations show the highest radioactivity. In most European countries groundwater is used as a source of drinking water. Groundwater is in contact with soil and rock and it is able to dissolve the radionuclides generated in the decay series of uranium and thorium from the surrounding media. As a result, radionuclides can be integrated into the chemical composition of groundwater in concentrations that may exceed the standards required by legislation.
Impact of added Inconel and stainless steel on zirconium-based alloys for nuclear waste applications
Published in Corrosion Engineering, Science and Technology, 2022
V. K. Gattu, S. Han, X. Chen, H. S. Park, W. L. Ebert, J. E. Indacochea
Chemically and physically durable waste forms are used to contain hazardous and high-level heterogeneous radioactive wastes during handling, storage and transport operations and isolate long-lived radionuclides during final disposal in a geological repository. Metallic waste forms are being developed to encapsulate waste streams generated during electrometallurgical conditioning of spent reactor fuel [1–3]. The principle radionuclides in metallic fuel waste streams are technetium alloyed in noble metal particles (commonly referred to as epsilon phases) and residual fission products not recovered during processing. It has been shown that different host phases formed in alloys made with mixtures of stainless steel (SS) cladding and metallic wastes from processed U-15Zr fuel serve to immobilise particular waste elements [4–10]: technetium reports to ferritic solid solution phases and actinides report to Fe2Zr Laves-type intermetallic phases [11–13]. The compositions and relative amounts of constituent phases generated during waste form processing can be tailored by waste loading, adding trim metals and processing conditions. For example, the addition of small amounts of trim molybdenum and chromium has been shown to improve the durability of host phases generated in steel-based alloy waste forms [14–17].
Microalgae and bio-polymeric adsorbents: an integrative approach giving new directions to wastewater treatment
Published in International Journal of Phytoremediation, 2022
Palak Saket, Mrinal Kashyap, Kiran Bala, Abhijeet Joshi
Radionuclides have high importance in the health care system and human life, especially in diagnostics. Radionuclides are unstable nuclei with an immense amount of energy, which decay by releasing ionizing particles like alpha, beta and gamma radiations (Carocci et al.2015). According to the World Nuclear Association database (2019), worldwide nuclear electricity production is 2563 billion kWh. The presence of radioactive contaminants in soil, water and air can produce severe health and environmental problems. Nuclear power plants, dumping of radioactive waste, nuclear accidents, release from mining sites are the primary sources of radioactive pollution in the environment. These pollutants enter the human body through the food chain or direct exposure by air or water and effectively cause damage at the molecular or cellular level leading to damages like kidney disorders, osteological problems, skin cancer and hematopoiesis (Lourenço et al.2016). Solodov et al. (1998) reported the presence of 3.6 × 106 TBq (terabequerel) of 137CS and 7.4 × 105 TBq of 90Sr in Lake Karachai, Russia (Solodov et al.1998). EPA (Environmental Protection Act) limits the total alpha activity in drinking water to 560 mBq/l (Surbeck 1995). Radionuclides get deposited on the layer of soil or interact with the component of soil and get accumulated for easy integration into the food chain (Das 2012).