Modeling the Radiological Impact of Tritium in Sewage Sludge Being Used as Fertilizer

A study was undertaken to assess the radiological impact on humans via the foodchain resulting from the presence of tritium and C-14 in sewage sludge being used as fertilizer on agricultural land. The key endpoint of the assessment was the annual individual dose to an average member of potential critical groups. As part of the assessment, a model was developed to simulate the distribution of tritium between sewage sludge and effluent in the sewage treatment plant, the release of tritium upon sludge decomposition and subsequent uptake by plants and animals. The modeling assumptions, as well as key parameters and parameter values will be discussed in this paper.