Isotopic signatureAn isotopic signature (also isotopic fingerprint) is a ratio of non-radiogenic 'stable isotopes', stable radiogenic isotopes, or unstable radioactive isotopes of particular elements in an investigated material. The ratios of isotopes in a sample material are measured by isotope-ratio mass spectrometry against an isotopic reference material. This process is called isotope analysis. The atomic mass of different isotopes affect their chemical kinetic behavior, leading to natural isotope separation processes.
Stable isotope ratioThe term stable isotope has a meaning similar to stable nuclide, but is preferably used when speaking of nuclides of a specific element. Hence, the plural form stable isotopes usually refers to isotopes of the same element. The relative abundance of such stable isotopes can be measured experimentally (isotope analysis), yielding an isotope ratio that can be used as a research tool. Theoretically, such stable isotopes could include the radiogenic daughter products of radioactive decay, used in radiometric dating.
Water purificationWater purification is the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from water. The goal is to produce water that is fit for specific purposes. Most water is purified and disinfected for human consumption (drinking water), but water purification may also be carried out for a variety of other purposes, including medical, pharmacological, chemical, and industrial applications. The history of water purification includes a wide variety of methods.
Disinfection by-productDisinfection by-products (DBPs) are organic and inorganic compounds resulting from chemical reactions between organic and inorganic substances such as contaminates and chemical treatment disinfection agents, respectively, in water during water disinfection processes. Chlorinated disinfection agents such as chlorine and monochloramine are strong oxidizing agents introduced into water in order to destroy pathogenic microbes, to oxidize taste/odor-forming compounds, and to form a disinfectant residual so water can reach the consumer tap safe from microbial contamination.
Isotope fractionationIsotope fractionation describes fractionation processes that affect the relative abundance of isotopes, phenomena which are taken advantage of in isotope geochemistry and other fields. Normally, the focus is on stable isotopes of the same element. Isotopic fractionation can be measured by isotope analysis, using isotope-ratio mass spectrometry or cavity ring-down spectroscopy to measure ratios of isotopes, an important tool to understand geochemical and biological systems.
Isotope analysisIsotope analysis is the identification of isotopic signature, abundance of certain stable isotopes of chemical elements within organic and inorganic compounds. Isotopic analysis can be used to understand the flow of energy through a food web, to reconstruct past environmental and climatic conditions, to investigate human and animal diets, for food authentification, and a variety of other physical, geological, palaeontological and chemical processes.
Water treatmentWater treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
Isotope geochemistryIsotope geochemistry is an aspect of geology based upon the study of natural variations in the relative abundances of isotopes of various elements. Variations in isotopic abundance are measured by isotope ratio mass spectrometry, and can reveal information about the ages and origins of rock, air or water bodies, or processes of mixing between them. Stable isotope geochemistry is largely concerned with isotopic variations arising from mass-dependent isotope fractionation, whereas radiogenic isotope geochemistry is concerned with the products of natural radioactivity.
Ultraviolet germicidal irradiationUltraviolet germicidal irradiation (UVGI) is a disinfection technique employing ultraviolet (UV) light, particularly UV-C (180-280 nm), to kill or inactivate microorganisms. UVGI primarily inactivates microbes by damaging their genetic material, thereby inhibiting their capacity to carry out vital functions. The use of UVGI extends to an array of applications, encompassing food, surface, air, and water disinfection. UVGI devices can inactivate microorganisms including bacteria, viruses, fungi, molds, and other pathogens.
Isotopic labelingIsotopic labeling (or isotopic labelling) is a technique used to track the passage of an isotope (an atom with a detectable variation in neutron count) through a reaction, metabolic pathway, or cell. The reactant is 'labeled' by replacing specific atoms by their isotope. The reactant is then allowed to undergo the reaction. The position of the isotopes in the products is measured to determine the sequence the isotopic atom followed in the reaction or the cell's metabolic pathway.
