Tritiated water is a

radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consi ...

form of

water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...

in which the usual protium atoms are replaced with

tritium Tritium ( or , ) or hydrogen-3 (symbol T or H) is a rare and radioactive isotope of hydrogen with half-life about 12 years. The nucleus of tritium (t, sometimes called a ''triton'') contains one proton and two neutrons, whereas the nucleus of ...

. In its pure form it may be called tritium oxide (T₂O or ³H₂O) or super-heavy water. Pure T₂O is

corrosive A corrosive substance is one that will damage or destroy other substances with which it comes into contact by means of a chemical reaction. Etymology The word ''corrosive'' is derived from the Latin verb ''corrodere'', which means ''to gnaw'', ...

due to self- radiolysis. Diluted, tritiated water is mainly H₂O plus some HTO (³HOH). It is also used as a tracer for water transport studies in life-science research. Furthermore, since it naturally occurs in minute quantities, it can be used to determine the age of various water-based liquids, such as vintage

wines Wine is an alcoholic drink typically made from fermented grapes. Yeast consumes the sugar in the grapes and converts it to ethanol and carbon dioxide, releasing heat in the process. Different varieties of grapes and strains of yeasts are m ...

. The name ''super-heavy water'' helps distinguish the tritiated material from heavy water, which contains

deuterium Deuterium (or hydrogen-2, symbol or deuterium, also known as heavy hydrogen) is one of two stable isotopes of hydrogen (the other being protium, or hydrogen-1). The nucleus of a deuterium atom, called a deuteron, contains one proton and one ...

instead.

Applications

Tritiated water can be used to measure the total volume of water in one's body. Tritiated water distributes itself into all body compartments relatively quickly. The concentration of tritiated water in

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellular ...

is assumed to be similar to the concentration of tritiated water in the body. Knowing the original amount of tritiated water that was ingested and the concentration, one can calculate the volume of water in the body. * Amount of tritiated water (mg) = Concentration of tritiated water (mg/ml) × Volume of body water (ml) * Volume of body water (ml) = mount of tritiated water (mg) − Amount excreted (mg)/ Concentration of tritiated water (mg/ml)

Adverse health effects

Tritiated water contains the radioactive hydrogen isotope tritium. As a low energy

beta emitter In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. For exam ...

with a half-life of about 12 years, it is not dangerous externally because its beta particles are unable to penetrate the skin. However, it is a radiation hazard when inhaled, ingested via food or water, or absorbed through the skin.Osborne, R.V. (August 2007
Review of the Greenpeace report: "Tritium Hazard Report: Pollution and Radiation Risk from Canadian Nuclear Facilities"
nuclearfaq.ca
U.S. Nuclear Regulatory Commission HTO has a short

biological half-life Biological half-life (also known as elimination half-life, pharmacologic half-life) is the time taken for concentration of a biological substance (such as a medication) to decrease from its maximum concentration ( Cmax) to half of Cmax in the bl ...

in the human body of 7 to 14 days, which both reduces the total effects of single-incident ingestion and precludes long-term bioaccumulation of HTO from the environment. Biological half-life of tritiated water in the human body, which is a measure of body water turnover, varies with season. Studies on the biological half-life of occupational radiation workers for free water tritium in the coastal region of

Karnataka, India Karnataka (; ISO: , , also known as Karunāḍu) is a state in the southwestern region of India. It was formed on 1 November 1956, with the passage of the States Reorganisation Act. Originally known as Mysore State , it was renamed ''Karnat ...

show that the biological half-life in the winter season is twice that of the summer season.

References

{{Oxygen compounds Nuclear materials Forms of water Body water