Assessment of inorganic priority pollutants in contaminated soils:: Harmonization of analytical protocols for heavy metal extraction:: Analytical speciation

In environmental studies heavy metals as well as some metalloids, such as arsenic, are considered as priority pollutants. The development and use of extraction schemes aims the evaluation of the metal fractions available to plants and the evaluation of the mobility of element under changing environmental parameters. The extracting agents are not selective and the "extractable metal" is defined under operational conditions. The lack of harmonized procedures did not allow the results to be compared worldwide. The first part of the current chapter deals on the studies carried out within the Standards Measurements and Testing Program (formerly BCR) of the European Union and the proposals of extraction systems for both soils and sediments, as well as the production of soils Certified Reference Materials for extractable metals, in such Programs our research group participated actively. A second strategy is based on analytical speciation. Such approach permits the extraction, separation and quantification of the chemical species present in the soil. The knowledge of the chemical species is a valuable tool for further studies on metal transport and on their translocation in plants. The main goal of that strategy is to achieve the separation and quantification of the chemical species of the element of interest with the highest possible selectivity and sensitivity while maintaining its integrity. The second part of the present chapter deals mainly on the studies carried out in our group on arsenic speciation in soils by emphasizing on some critical analytical aspects such as the stability of the species during the analysis as well as their recovery. Some of our recent studies on selenium speciation in soils and some new results on the most recent studies on antimony speciation are also reported.