A final report on the ICES intercalibration for trace metals in marine sediments (1/TM/MS)

Forty participants of 1/TM/MS determined all or in part Al, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Ti, and Zn concentra tions in replicate digests of three sediment samples using 4 dissolution/extraction procedures, and a separate procedure for Hg. Data analysis shows that the intra-lab precisions were acceptable for most metal determinations except Hg. The overall inter-lab agreements were, however, unacceptable for total(HF) Cd, Cr, and Ni, and total(H₂SO₄+HNO₃) Hg concentrations in all three samples, and were also unacceptable for most of the metals determined after dissolution/extraction by aqua regia, lN HCl, or 25%v/v HOAc. HF + aqua regia dissolution proved to be the most effective method for removing the total metal concentrations from the samples, and 25 % v/v HO Ac was shown to be a weaker acid attack than lN HCl.