OPERATIONALLY DEFINED EXTRACTION PROCEDURES FOR SOIL AND SEDIMENT ANALYSIS - II - CERTIFIED REFERENCE MATERIALS

Single or sequential extraction procedures are often used for soil and sediment studies to determine forms or phases of elements (e.g. 'bioa vailable' forms of elements). The significance of the analytical resul ts is highly dependent on the extraction procedures used, owing to the 'operationally defined' character of these schemes which requires the adoption of standardized protocols. The first part of the present rev iew discusses the aspects of standardization of leaching and extractio n schemes as applied to environmental analysis. This second part focus es on the validation aspects of such procedures and describes the prep aration and certification of soil and sediment reference materials cer tified for their extractable trace element contents, following standar dized single and sequential extraction procedures. (C) 1998 Elsevier S cience B.V. All rights reserved.