CERTIFIED REFERENCE MATERIAL FOR THE QUALITY-CONTROL OF EDTA-EXTRACTABLE AND DTPA-EXTRACTABLE TRACE-METAL CONTENTS IN CALCAREOUS SOIL (CRM-600)

Single extraction tests are commonly used to study the eco-toxicity an d mobility of metals in soils, e.g. to assess the bioavailable metal f raction (and thus to estimate the related phyto-toxic and nutritional deficiency effects) and the environmentally accessible trace metals up on disposal of e.g. sediment on to a soil (e.g. contamination of groun d waters). However, the lack of uniformity in the different procedures does not allow the results to be compared worldwide nor the procedure s to be validated. This paper describes the interlaboratory testing of EDTA- and DTPA-extraction procedures for soil analysis, followed by t he preparation of a calcareous soil reference material (CRM 600), the homogeneity and stability studies and the analytical work performed fo r the certification of the EDTA- and DTPA-extractable contents of some trace metals (following the standardized extraction procedures).