Chemical associations of artificial radionuclides in Cumbrian soils

The distributions of radionuclides in the surface layer of four soils of contrasting types from west Cumbria, UK, have been studied in detail. All the soils contain enhanced levels of artificial radionuclides derived from low-level discharges both to sea and to atmosphere from the British Nuclear Fuels reprocessing plant at Sellafield. The bulk of the activity is held in the top 15 cm of soil profiles, suggesting that radionuclide mobility is limited. Sequential extraction experiments have identified major associations of plutonium with organic matter and of caesium with silicates but there is no preferential association of ruthenium with any single soil component.