This article summarises some key activities undertaken as part of a NATO-funded project to map and improve our understanding of the behaviour and fate of radionuclides in the Belarusian Sector of the Chernobyl Exclusion zone. Data are presented concerning activity concentrations of 137Cs, 90Sr and selected actinides and how these data have been used to produce contour maps of contamination densities. Factors affecting the transfer of radionuclides to plants and animals at selected study sites are considered and the geochemical phase association of radionulcides in soils and implications for actinide mobility commented upon. A final important subject for elaboration has been the transboundary transport of contamination by natural phenomena. The influence of forest fires on remobilisation of radionuclides, for example, has been addressed through the application of a bespoke probabilistic model.