Environmental isotopes

Environmental isotopes are variants of chemical elements that contain the same number of protons but differ in the number of neutrons, resulting in different atomic masses. These isotopes can serve as important tools in environmental science, ecology, geochemistry, and other fields, as they can provide valuable information about various environmental processes, historical climate conditions, and the movement of water and other substances in the environment. Isotopes can be stable or unstable (radioactive).

Carbon-13 (C-13) is a stable isotope of carbon, which has an atomic mass of approximately 13 atomic mass units (amu). It consists of six protons and seven neutrons in its nucleus, distinguishing it from the more common carbon isotope, Carbon-12 (C-12), which has six protons and six neutrons. Carbon-13 makes up about 1.1% of all naturally occurring carbon in the environment.

Carbon-14 (C-14) is a radioactive isotope of carbon. It is formed in the upper atmosphere when cosmic rays interact with nitrogen-14 (N-14) in a process known as cosmic ray spallation. Carbon-14 has a half-life of about 5,730 years, which means that it takes this amount of time for half of a given sample of C-14 to decay into nitrogen-14 through beta decay.

Chlorine-36 (\(^{36}\text{Cl}\)) is a stable isotope of chlorine, which is a chemical element with the symbol Cl and atomic number 17.

Deuterium is a stable isotope of hydrogen, represented by the symbol \( \text{D} \) or \( ^2\text{H} \). It contains one proton and one neutron in its nucleus, giving it a mass number of 2, compared to the more common hydrogen isotope, protium, which has no neutrons. Deuterium occurs naturally in small amounts in water, comprising about 0.0156% of all hydrogen in the ocean.

Environmental radioactivity refers to the presence and concentration of radioactive materials in the environment, including air, water, soil, and living organisms. This radioactivity is a natural phenomenon resulting from the decay of radioactive isotopes that are found in the earth's crust, cosmic radiation from outer space, and human-made sources. **Sources of Environmental Radioactivity:** 1. **Natural Sources:** - **Cosmic Rays:** High-energy particles from outer space that contribute to background radiation.

Extinct isotopes of superheavy elements refer to isotopes of elements that lie beyond the currently known periodic table. Superheavy elements are those with atomic numbers greater than 103 (lawrencium) and are typically synthesized in laboratories through nuclear reactions. These elements are often highly unstable, with very short half-lives, leading them to decay rapidly into lighter elements.

Oxygen-17 (³¹₆O) is a stable isotope of oxygen. It contains 8 neutrons and 9 protons in its nucleus, giving it a mass number of 17. In naturally occurring oxygen, about 0.037% is this isotope, making it relatively rare compared to the more common isotopes, Oxygen-16 (the most abundant) and Oxygen-18.

Oxygen-18 (⁴O) is a stable isotope of oxygen that is characterized by having 8 protons and 10 neutrons in its nucleus. It is one of three naturally occurring isotopes of oxygen, the others being Oxygen-16 (⁴O) and Oxygen-17 (⁴O). Oxygen-18 is less abundant than Oxygen-16, making up about 0.2% of naturally occurring oxygen.

Tritium is a radioactive isotope of hydrogen, denoted as \( ^3H \) or T. It contains one proton and two neutrons in its nucleus, making it heavier than the most common hydrogen isotope, protium (\( ^1H \)), which has only one proton and no neutrons. Tritium is produced naturally in the atmosphere through interactions between cosmic rays and nitrogen.

Δ¹³C (delta carbon-13) is a measure used in the field of stable isotope geochemistry to express the ratio of carbon isotopes, specifically the stable isotopes carbon-12 (¹²C) and carbon-13 (¹³C). The delta notation is used to give the relative difference in the isotopic composition of a sample compared to a standard reference material.

Δ¹⁸O (Delta oxygen-18) is a measure of the ratio of stable isotopes of oxygen, specifically the ratio of oxygen-18 (¹⁸O) to oxygen-16 (¹⁶O). It is expressed as a difference in parts per thousand (‰) compared to a standard reference material, typically Vienna Standard Mean Ocean Water (VSMOW).

Δ⁻⁴S (delta sulfur-34) is a notation used in geochemistry and environmental science to express the isotopic composition of sulfur in a sample relative to a standard. Specifically, it refers to the ratio of sulfur-34 (¹⁴S) to sulfur-32 (¹³²S) isotopes.