Mobility test applied to a certified reference material BCR-483 – sewage sludge amended soil

Abstract

The aim of the study was to estimate the mobile forms of Cd, Ni and Pb from a certifed reference material BCR-483, which is a sewage sludge amended soil. In the study were tested 4 extraction procedures, 2 of them were used by the BCR European Commission. The BCR certifcate of analysis contains certifed value for mobile fraction of Cd, Ni and Pb extracted with 2 different solutions: 0.05 M EDTA and 0.43 M CH3COOH. The mobility tests include not only the values ob- tained with these 2 methods, but also the values obtained with another 2 single chemical extraction procedures, which used the following extractants: a buffer solution at pH = 7.3 of 0.005 M DTPA,0.1 M TEA and 0.01 M CaCl2, a mixture of 0.01 M EDTA and 1 M NH4OAc at pH = 7. The contents of Cd, Ni and Pb were analysed with flame atomic absorption spectrometry (FAAS). The experimental tests applied to BCR-483 with BCR methods proved that both extraction and determinationprocedures can provide valuable data, comparable with the certifed values for exchangeable fraction of Cd, Ni and Pb. The data obtained with the other 2 methods confrm the fact that the extractant type is very important in evaluating the mobility fraction of the metals (different concentrations of metallic elements obtained with different extraction procedures).