Tritium

EPA Maximum Contaminant Level (MCL)

Beta Particle Emitters

4 milirem / year

Tritium gas is used to illuminate some watches, exit signs, and key chains.

Tritium is a radioactive isotope that occurs naturally in the environment in very low concentrations. Most tritium in the environment is in the form of tritiated water, which easily disburses in the atmosphere, water bodies, soil, and rock. Like H₂O, tritiated water is colorless and odorless. Tritium has a half-life of 12.3 years and emits a very weak beta particle.

Sources of Tritium

Tritium is produced naturally in the upper atmosphere when cosmic rays strike nitrogen molecules in the air. Tritium is also produced during nuclear weapons explosions, as a byproduct in reactors producing electricity, and in special production reactors, where the isotope lithium-6 is bombarded to produce tritium.

Tritium is also used in various self-luminescent devices, such as exit signs in buildings, aircraft dials, gauges, luminous paints, and wristwatches. Tritium is used in life science research, and in studies investigating the metabolism of potential new drugs.

It is estimated that 1/4 of US nuclear plants are leaking tritium into drinking water supplies.

Health Effects of Tritium

According to the EPA:

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As with all ionizing radiation, exposure to tritium increases the risk of developing cancer. However, because it emits very low energy radiation and leaves the body relatively quickly, for a given amount of activity ingested, tritium is one of the least dangerous radionuclides. Since tritium is almost always found as water, it goes directly into soft tissues and organs. The associated dose to these tissues are generally uniform and dependent on the tissues' water content.

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Water Treatment for Tritiated Water

There is no known treatment. According to the United States Nuclear Regulatory Commission :

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Like normal hydrogen, tritium can bond with oxygen to form water. When this happens, the resulting water (called “tritiated water”) is radioactive. Tritiated water (not to be confused with heavy water) is chemically identical to normal water and the tritium cannot be filtered out of the water.

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Source: EPA, NRC, Photo: WikiMedia, author: bgran