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Technetium in Water

Physics and Chemistry of Water

  1. Jay Clausen

Published Online: 15 APR 2005

DOI: 10.1002/047147844X.pc546

Water Encyclopedia

Water Encyclopedia

How to Cite

Clausen, J. 2005. Technetium in Water. Water Encyclopedia. 4:578–583.

Author Information

  1. AMEC Earth and Environmental, Inc., Westford, Massachusetts

Publication History

  1. Published Online: 15 APR 2005


Technetium, element 43, was predicted on the basis of its location in the periodic table. Twenty-two isotopes of technetium whose masses range from 90 to 111 are known, and all are radioactive. Technetium has three long-lived radioactive isotopes: technetium-97 [97Tc] (half-life {T1/2} = 2.6 × 106 years), 98Tc (T1/2 = 4.2 × 106 years), and 99Tc (T1/2 = 2.13 × 105 years). An important isotope is 95mTc (“m” stands for metastable state) [T1/2 = 61 days], which is used in tracer work. However, the most useful isotope of technetium is 99mTc (T1/2 = 6.01 hours), which is used in many medical radioisotope tests because of its short half-life, easy detection of the gamma ray it emits, and the ability of technetium to bind chemically to many biologically active molecules

Technetium-99 is a surface water and groundwater contaminant at a number of DOE sites such as the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky; the Portsmouth Gaseous Diffusion Plant in Piketon, Ohio; Currently, the largest annual release of 99Tc to the environment occurs at the two nuclear fuel-reprocessing facilities in Sellafield, United Kingdom.

The most extensive groundwater distribution of 99Tc is at the PGDP where a inline image mile long plume of 99Tc contaminated groundwater is commingled with the solvent trichloroethene. The 99Tc was introduced to the site during the 1970s when fissioned uranium was reprocessed.

The technologies explored for remediating 99Tc in water include ion exchange, liquid–liquid extraction, precipitation with various forms of iron, redox manipulation, the FORAGER sponge, granular activated carbon (GAC), and natural attenuation.


  • contaminant;
  • half-life;
  • isotopes;
  • radionuclide;
  • technetium