Tritium in the Aquatic Environment

Abstract Tritium is of environmental importance because it is released from nuclear facilities in relatively large quantities and because it has a half-life of 12.26 y. Most of the tritium released into the atmosphere eventually reaches the aqueous environment where it is rapidly taken up by acquatic organisms. This paper reviews the current literature on tritium in the aquatic environment. Conclusions from the review, which covered algae, aquatic plants, invertebrates, fish, and food chain studies, were that aquatic organisms incorporate tritium into their tissue free water very rapidly and reach concentrations near that of the external medium. Incorporation of tritium from tritiated water into the organic matter of cells is at a slower rate than incorporation into the tissue free water. If organisms consume tritiated food, incorporation of tritium into the organic matter is faster and a higher tritium concentration is reached than when the organisms are exposed to only tritiated water. Incorporation of tritium bound to molecules into the organic matter depends on the chemical form of the 'carrier' molecule. No evidence was found that biomagnification of tritium occurs at higher trophic levels. Radiation doses to large populations of humans from tritium releases will most likely be from the consumption of contaminated water rather than contaminated aquatic food products.