A new organic-rich soil reference material certified for its EDTA- and acetic acid- extractable contents of Cd, Cr, Cu, Ni, Pb and Zn, following collaboratively tested and harmonised procedures

There is an increasing requirement for assessment of the bioavailable metal fraction and the mobility of trace elements in soils upon disposal. One of the approaches is the use of leaching procedures, but the results obtained are operationally defined; therefore, their significance is highly depende nt on the extraction protocol performed. So, for this type of study, there is a need for reference materials that allow the quality of measurements to be controlled. This paper describes the steps involved in the certificatio n of an organic-rich soil reference material, BCR-700, for the EDTA- and ac etic acid-extractable contents of some trace elements, following collaborat ively tested and harmonised extraction procedures. Details are given for th e preparation of the soil, homogeneity and stability testing, analytical pr ocedures and the statistical selection of data to be included in the certif ication.