Effects of chemical speciation of Sulphur-35 released into the atmosphere

Last updated:
1 March 2008
Investigation of the effects of chemical speciation of Sulphur-35 released into the atmosphere on uptake by crops and animals
Study duration: February 2008 to August 2008
Project code: R04006
Contractor: Nicholson Environmental


The Food Standards Agency is responsible for protecting the food supply from undue or unacceptable contamination with radioactivity. In order to discharge this responsibility, the Agency needs to be able to predict radiological doses to consumers that can result from planned and accidental discharges. In the case of S-35, there are significant differences between the measured and predicted levels in foodstuffs. Consequently, there is a need to better understand this discrepancy and to determine whether it is through the modelling or the measurements that these differences arise.

There is still some uncertainty over the chemical forms with which S-35 is associated (e.g. H2S and COS) both prior and subsequent to its release from the UK nuclear power industry. Moreover, there are uncertainties also with the behaviour of these chemical species in the environment and their uptake into foodstuffs. This study will review and address these uncertainties. This will help elucidate the differences between the measurements and modelling predictions for S-35, thus assisting the Food Standards Agency to discharge its responsibilities.

Research Approach

The project will proceed via the following three phases:

  • A full assessment of the reported levels of S-35 measured in environmental media and a comparison of these with modelling results
  • An overview of the forms and behaviour of S-35 released from the UK nuclear industry and its likely behaviour in the atmosphere
  • Review of the modelling assumptions and the identification of the causes for differences between modelled and measured results for S-35 in environmental media


Additional Info


Published Papers