Additional Certified Values for CCRMP Soils SO‐1 to ‐4

New mean values for up to 11 major and minor and up to 11 trace elements in soils SO-1 to SO4 have been calculated by two procedures. Analytical results received by CCRMP subsequent to the certification program of 1979 were included. In one instance, the same procedure as used for certification wherein all results except those rejected on chemical and/or statistical considerations was followed, but little improvement over the 1979 calculations was obtained. The other procedure is proposed by the authors for use in identifying concentration range intervals wherein maximum interlaboratory consensus is observed. The application of this procedure has permitted the certification of the four soils for the content of 24 elements not previously certified.