The National Soil Inventory (NSI), which was carried out between 1978 and 1982, sought to provide a geochemical profile of the soils of England and Wales. This study will re-sample selected sites surveyed in the original Inventory in order to evaluate whether levels of potentially toxic elements in the soil, together with soil pH and organic carbon values, have changed over time. The study will concentrate on those changes which can be attributed to agriculture, especially intensive practices. Sampling will be restricted to those sites originally described as permanent or managed grassland and will consist of approximately 800 out of 1558 such sites originally surveyed. Organic carbon, pH, nutrients, acid extractable fluoride and EDTA extractable elements will be determined using methods similar to those used during the original survey. The project will measure the level of caesium in soils, with initial aqua regia extracts being processed 3 times in different batches; this will show whether the analytical signal is stable at appropriate solution concentrations. A Certified Reference Material will also be used to develop a method for determination of platinum, rhodium and palladium in soils, which will be applied to determine the concentrations of these elements in 10% of samples taken from sites near to conurbations and main roads. Moreover, 10% of samples used in the original study will also be re-analysed as a check against changes induced by modifications in equipment, storage and methodology. Results will be used to monitor the status of the UK's soils and the rate at which they might be changing, and will contribute to aims relating to maintenance of soil sustainability.