Heavy metal pollution of irrigated soils in Ningxia, China

The recent accelaration of industrial management causes a distinct heavy metal pollution of water and soils in the irrigation area of Ningxia Region, China. The contents of Cr and Ni in the soils exceed the tolerable contents of these metals defined for European soils. Cu and Zn contents are 2-3 times higher than their contents in the geochemical background of European soils and in loessial soils from the Ningxia Upland. For soils in the neighbourhood of industrial centers an ascending tendency of heavy metal contents was noted. It can be concluded that industrial pollution is responsible for the high heavy metal contents of irrigated soils in the whole region.