This report (PHE-CRCE-008) describes experimental studies on how the radionuclide technetium-99 is transferred into terrestrial crops.
A review published in 2011 by the Health Protection Agency (the functions of which transferred to Public Health England in 2013) found that the availability for the root uptake of technetium into crops depends on whether the technetium is in a chemically non-reduced, more plant available form, such as TcO4–, or a chemically reduced, less plant available form, such as TcO2. Based on the review, generic soil to crop transfer factor (TF) values for use in non-site-specific UK based radiological assessments were proposed, with the TF value for the reduced form of technetium in crops around a factor of 10 lower than that for the non-reduced form.
The aim of this small-scale experimental study was to provide further evidence that the generic assumption made on the difference between soil to crop transfer factor (TF) values for non-reduced and reduced forms of technetium is valid. The study was also designed to establish likely time periods over which the chemical reduction of technetium takes place and to provide additional soil to crop TF values for use in UK based radiological assessments.