Acceptable levels of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn) in soils depending on their clay and humus content and cation-exchange capacity

Abstract

Three sandy soils differing in humus content and three clay soils differing in clay content were supplied with heavy metals to determine which loading rate of each single metal should be regarded as critical from the viewpoint of crop yield and metal content dependent on soil cation exchange capacity (CEC), which in USDA recommendations is used as a measure of the loading capacity of soils with heavy metals