Determination of heavy metals and their speciation in lake sediments by flame atomic absorption spectrometry after a four-stage sequential extraction procedure

A four-stage sequential extraction procedure for determination of the speciation of extractable heavy metals, proposed by the Commission of the European Communities Bureau of Reference (BCR) as a mean of comparison of data of extractable heavy metals, has been applied to lake sediments collected from the lakes of a water-laden area of Sultansazligi, Kayseri, Turkey. The determination of extractable heavy metals such as chromium, cobalt, nickel, copper, zinc, cadmium (below the detection limit), lead, manganese and iron in the sediment samples was carried out by flame atomic absorption spectrometry (FAAS) using an injection method. Acetic acid, hydroxyl ammonium chloride, hydrogen peroxide plus ammonium acetate, and aqua regia stages of the sequential extraction procedure were applied to the sediment samples, respectively. Recoveries were quantitative (greater than or equal to 95%). The accuracy obtained by comparing the pseudo-total metal concentrations with the sum of the four extraction stages, was found to be satisfactory. The limit of detection for different elements was found to be between 0.04 and 0.69 mu g ml(-1) for the various extraction stages. (C) 2000 Elsevier Science B.V. All rights reserved.