Use of a sequential extraction scheme with data normalisation to assess the metal distribution in agricultural soils irrigated by lake water

Multi-element analysis was performed in a sandy loam and a loam agricultural soil irrigated with water from a relatively polluted lake applying a sequential extraction procedure. Extracts were analyzed for: Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn. The concept of data normalisation is introduced, yielding interesting information on the relative intrinsic affinity of some of the metals for the separate phases of the soil system. The results indicated a low percentage of easily exchangeable and carbonate bound metals. For certain elements, the study revealed new information for the separate extracted phases as regards the relative retention behaviour of these metals. The majority of the metals extracted were found in the oxidizable organically boundqsulphides. and reducible Fe]Mn oxyhydroxides. fractions. These fractions are considered as the most efficient scavengers for the studied metals. Total metal analysis showed an enrichment of some elements in the surface soils as a result of agricultural and anthropogenic activities. The depth variation of heavy metals in the core soils in connection with extractability by EDTA suggests a relatively high mobility of Pb, Cu, Co and Mn. The results of this study present both an issue of local interest and the interpretation of the trend of the binding metals in the phases of soil systems using a simple normalization method.