Determination of the extractability of selected phytotoxic elements from soil

Copper is an essential element for plants, but in higher concentrations it exhibits phytotoxic reactions. Chromium and aluminium, however, are not considered as plant nutrients, but their presence in plants can affect the normal function of some other elements, thus they might be harmful to plants. Various soil samples were analysed by BCR sequential extractions to study the bioavailability of Cr, Cu, and Al, and furthermore they were digested to obtain the total metal content in soil using inductively coupled plasma – atomic emission spectroscopy. Based on these results the extractions yields were calculated as basis for estimating sufficient supply as well as for risk assessment studies regarding the elements chosen. A minimum concentration of copper in soil of 4-5 mg/kg has to be guaranteed for normal plant growth. In the soils analysed the total metal contents ranged from 14-31 mg/kg for chromium, from 8-32 mg/kg for copper and 9-23 g/kg for aluminium. The total extraction yields were calculated to be 60-100%, 55-100% and 30-80% for Cr, Cu and Al, respectively.