Chemical detection of heavy metals applied at high rates to soil

The detection of eight micropollutants was studied in a field trial. Al, As, Cd, Cr, Cu, Hg, Pb, and Zn soluble salts were applied at rates of 30, 90, and 270 kg ha(-1). The total element content was measured using HNO3+H2O2, and the exchangeable/soluble content was measured with NH4-acetate+EDTA extraction. After 1 year, nearly all of the applied Cu, Pb, Cd, Zn, and As could still be detected in the plow layer in an exchangeable form, but the Cr and Hg were not detectable. Two years later, approximately two-thirds of the added Cd and only about one-third of the applied Cu, Pb, Zn, and As were found in exchangeable forms, whereas Cr and Hg were only marginally detected. With time, fixation of these elements in less exchangeable forms occurred. Cadmium remained exchangeable for a longer time than the other elements and could be measured by both analytical methods.