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Discharges of tritium from UK nuclear and non-nuclear sites are usually assumed to be in the form of tritiated water (HTO). However, a proportion of HTO may be converted to organically bound tritium (OBT). Discharges from Nycomed Amersham (Cardiff) are unusual in that they contain tritium specifically as OBT, but marine dispersion modelling, and dose assessments, are based on tritiated water. <p>The behaviour of OBT in the environment would be different from HTO. Little is known about the proportion of OBT present in foodstuffs, but the committed effective dose from OBT is higher than that from a comparable activity of HTO. The project will enable the assessment of the specific impact of OBT in critical group dose assessments.
Laboratory-based studies<br>
The design of analytical protocols to better distinguish and quantify the various forms of tritium in environmental samples. Identification and asessment of routes of interconversion between tritiated water and non-aqueous forms of tritium. Sequential extraction and size separation of intertidal mudflat and saltmarsh sediment samples from Cardiff Bay and the Cumbrian coast. Batch experiments to examine the impact of variation in salinity, PH and redox state on the release of tritium from sediment samples.<p>
Field-based studies<br>
Collation of data from environmental tritium studies, to aid site selection and sample collection. Determination of spatial distribution of tritium species in sediments from Cardiff Bay and the Cumbrian coast. Extraction and analysis of biological material
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Find more about this project and other FSA food safety-related projects at the <a href="http://www.food.gov.uk/science/research/" target="_blank">Food Standards Agency Research webpage</a>.