IMPROVEMENT OF ANALYTICAL MEASUREMENTS WITHIN THE BCR-PROGRAM - SINGLE AND SEQUENTIAL EXTRACTION PROCEDURES APPLIED TO SOIL AND SEDIMENT ANALYSIS

The determination of extractable trace metal contents in soil and sedi ment, using respectively single and sequential extraction procedures, is currently performed in many laboratories to assess the bioavailable metal fraction (and related phyto-toxic effects) and the accessabilit y lo the environment (e.g. contamination of ground waters). Owing to t he need for validation of the extraction schemes used and of the analy tical techniques, the Community Bureau of Reference (BCR) decided to o rganize a project for the improvement of the quality of determinations of extractable trace metal contents in soil and sediment. The impleme ntation of this project follows a stepwise approach involving feasibil ity studies, intercomparisons to detect and remove sources of errors i n the application of the analytical methods, and the certification of the extractable compounds. This paper describes the organization of th e work completed so far (feasibility studies and first intercomparison ) and discusses its further development.