The influence of grassland management on the radionuclide inventory of soils in West Cumbria, UK

The 137Cs, 239,240Pu, 238Pu, 241Am and 40K activities in soils and vegetation under grassland management in west Cumbria were investigated. Uptake of these radionuclides by the vegetation is affected by the land management practices employed. The more intensively utilised areas have lower concentrations in soils and the plants show reduced uptakes of the artificial radionuclides. It is proposed that this is due to differences in the physical mixing of the soil, natural and artificial chemical additives, contamination of the vegetation with soil by animal usage and the regular cropping of grass for silage. Comparison of the soil data with samples taken on Exmoor indicates that the west Cumbrian samples were enriched by factors of ∼2·5 for 137Cs and ∼10 for 239,240Pu.