2.3.3. Sequential chemical extractions
Heavy metals in soil were determined by a three-step sequential
extraction method based on the BCR (Community Bureau of
Reference), which is summarized in Table 1 according to the procedure
presented by Rauret et al. (2000).
A Heidolph Reax 20 overhead shaker, at 16 rpm and room
temperature, was used to obtain each extract. Between each step,
separation of the extract from the solid was undertaken by
centrifugation at 3000 rpm for 20 min followed by decantation of
the supernatant liquid. According to Sulkowski and Hirner (2006),