The three-stage sequential extraction procedure recommended by BCR has been applied in the operational speciation of cadmium and lead in a relatively unpolluted freshwater sediment, following various types of sample pre-treatment. Changes in speciation occurred when the sediment was air-dried, oven-dried or frozen. Cadmium speciation was particularly perturbed by freezing, whilst lead was more affected by oven-drying. Metals were deter mined by electrothermal atomic absorption spectrometry, using direct calibration with reagent-matched standard solutions.
- freshwater sediment
- three-stage sequential extraction procedure