Radioactivity can be released to the environment in particulate form, for example as a result of erosion of a landfill containing radium contaminated items at Dalgety Bay and the historical release of irradiated fuel particles from the Dounreay site. Particles behave in a specific way within the environment and are associated with specific potential exposure scenarios and pathways. For example, it is necessary to assess exposures and uptakes from particles in quite a different way from contamination present in other, natural media. Quintessa is experienced in assessing particle transport and potential exposure in support of remediation decisions.