Cadmium and Uranium Contents in Soils: Screening of Arable Soils in the Midlands

The results from the cadmium and uranium screening in arable soils indicate that these potentially toxic metals enter agricultural areas through mineral fertilisation and can accumulate in soils. Regarding lead and arsenic, negligible amounts are introduced with mineral fertilisers. At three of six NABO sites selected for the screening, an increase in cadmium of 0.02-0.1 mg/kg per year and in uranium of 0.1-0.7 mg/kg per year was measured in the topsoil, relative to a period of two decades.

In general, the metal accumulation in intensively used agricultural areas can further increase. The measures to minimise cadmium and uranium inputs in the soil include, among others, better control of the Cd threshold values for P mineral fertilisers and the monitoring of soil water, ground water and surface water bodies.

Figure: Overview of the soils and arable farming sites analysed for the screening of cadmium and uranium.

For the screening, 400 soil samples from 228 sites (Figure) were analysed. Among these sites are areas treated with mineral fertilisers of the National Soil Monitoring Network (NABO), sites in areas of arable farming of the Swiss Biodiversity Monitoring (BDM) as well as the networks of the Cantonal Soil Monitoring (KABO). For six selected NABO sites, for which records of regular P mineral fertiliser inputs exist, additional balances were generated for the metal inputs via fertiliser and atmospheric deposits and for the removal via harvested material, during the period between 1985 and 2013.