Sequential Schemes for Metals in Soil or Sediment

One of the classic methods for speciation of metals in soils was developed by Tessier et al. [125], and this method is still substantially in use, although several modifications of this method have also been published. Again, it is important to stress that even small modifications of the methods used can have substantial effects on the data obtained. 

The first extraction of easily exchangeable metal ions is done at room temperature with a 1 M solution of MgCl2, at pH 7 for 1 hour with continuous stirring. Extraction 2 in the sequence removes the metals bound to carbonate minerals by extraction with acetate buffer at pH 5. The extraction is complete within 5 hours for fine sediments but might take longer for 

Physical techniques based on size, density, or charge of the species 

Chemical techniques based on redox, complexation, and/or adsorption properties 

Species-specific techniques applicable to particular species 

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