The Behaviour and Availability of Cd, Ni and Pb in Polluted Soils

In a study of metals in soils, Pb was found to be the least soluble and least plant available element. Cd and Ni were much more soluble and were taken up by plants to a greater extent but the solubility of Cd and Pb varied inversely with soil pH. Cationic forms of Cd predominated in the soil solution. Of the four crops grown on these soils in the greenhouse, cabbage and lettuce had higher metal concentrations in their edible portions than carrot and radish. Uptake was generally greater from inorganically polluted soils. CaCl₂(0.05M) is a useful extractant for predicting the bioavailability of Cd.