LEAD AND CADMIUM CONTAMINATION IN DAIRY-PRODUCTS AND ITS REPERCUSSION ON TOTAL DIETARY-INTAKE

An accurate and precise method is described for the direct determination of lead and cadmium in dairy products, using slurried samples in combination with electrothermal atomic absorption spectrometry. The samples are suspended in Triton X-100 and shaken with 10.0 g of zirconia spheres until a slurry is formed. The slurry preparation procedure and the graphite furnace conditions were optimized for both elements. The results obtained were validated against microwave acid sample digestion. The detection limit was 0.4 pg for Pb and 0.5 pg for Cd. The analytical application of this method was tested with 60 samples of 10 widely consumed dairy products. The mean values ranged from not detectable to 0.750 mu g/g for Pb and from not detectable to 20.0 ng/g for Cd. Increased concentrations of lead and cadmium were detected in products packaged in glazed ceramic containers, Metal migration from the container was also tested. Because milk and dairy products are some of the most widely consumed foods in the human diet, they contribute a large fraction of the intake of trace elements. Strict control of trace element levels in these foods is therefore advisable.