Treatment of Chemotoxic Species in the Environmental Safety Case for a Geological Disposal Facility

Two reports on the treatment of chemotoxic species in the Environmental Safety Case for a Geological Disposal Facility (GDF) for UK radioactive waste have been produced by Quintessa on behalf of the Nuclear Decommissioning Authority Radioactive Waste Management Directorate (NDA RWMD).

The first [1] provides a detailed assessment of the possible release of priority chemotoxic substances from a generic GDF, and quantitatively assesses human exposures and potential associated health risks posed by such releases. In the second report [2], a literature review is provided on additive and synergistic effects for radiological and chemical toxins and, using the data from the first report, an assessment is provided of the likelihood of additive and synergistic effects occurring as a result of releases from a generic GDF.

The general approach adopted in this work illustrates an approach by which the relevant regulations concerning the non-radiological components of a radioactive waste inventory as relating to a GDF can be progressed. The work also demonstrates that synergistic/additive effects (for chemical mixtures and chemotoxic-radiotoxic interactions) can be considered proportionately in such an approach. A key issue highlighted by this work relates to the availability of relevant toxicological data required as input to any quantitative assessment; as these are limited, future work may need to consider alternative, more qualitative approaches to address this issue.

[1] Wilson, J., Thorne, M. And Towler, G. (2009) Treatment of Chemotoxic Species (1) Quantitative Human Health Risk Assessment. Quintessa Report QRS-1378M-1.1, for NDA RWMD. Nuclear Decommissioning Authority, Harwell,UK.

[2] Thorne, M. and Wilson, J. (2009) Treatment of Chemotoxic Species (2) Review of Additive and Synergistic Effects. Quintessa Report QRS-1378M-2.1, for NDA RWMD. Nuclear Decommissioning Authority, Harwell, UK.