MICROWAVE DIGESTION TECHNIQUE FOR THE DETERMINATION OF TOTAL CADMIUM IN SOILS

A rapid method is described for the determination of total cadmium (Cd ) in soils. The soil samples and standard sediment samples were digest ed in a microwave oven using concentrated HNO3 and also by the convent ional HF-HClO4 digestion in platinum crucibles. The Cd content in the extracts was determined using graphite furnace atomic absorption spect ro-photometry (GFAAS). Both digestion methods produced comparable quan titative values for total Cd of standard reference materials obtained from the National Institute of Standards and Technology and a series o f surface and subsurface soil samples. Thus, the microwave digestion t echnique was shown to be an accurate and rapid method for digesting so il samples prior to total Cd analysis.