HPA-CRCE-025: Review of the transfer of technetium to terrestrial crops and animal products

Synopsis

Technetium-99 (⁹⁹Tc) has been dispersed in the environment from many sources such as nuclear weapons testing, releases from medical or industrial processes, nuclear power plants and nuclear fuel processing facilities. For 99Tc, interest in environmental transfer has increased because of its relative importance in radiological assessments for nuclear waste repositories. An adequate knowledge of any radionuclide's behaviour in terrestrial foodchains is important for assessing the radiological impact on people following the release of radioactive material into the environment.

The aim of this study was to carry out a critical review of published data on the transfer of technetium into terrestrial crops and animal products and to recommend transfer factor (TF) values for use in UK based radiological assessments.

This review has identified that the chemical form of technetium in soil is the main factor that determines the degree to which it is available for uptake to crops. TF values have been compiled for a range of crop types and for technetium in a chemically reduced and non-reduced form, where data are available.

The compiled TF values have been compared with default parameters currently used in HPA's foodchain model, FARMLAND. Recommended values of transfer factors for specific applications of FARMLAND for radiological assessments in the UK are proposed.

Last reviewed: 23 August 2011