ANALYTICAL INTERCOMPARISON RESULTS FROM THE 1990 INTERGOVERNMENTAL-OCEANOGRAPHIC-COMMISSION OPEN-OCEAN BASE-LINE SURVEY FOR TRACE-METALS - ATLANTIC-OCEAN

''Dissolved'' (< 0.4 mu m filtered) and ''total dissolvable'' (unfilte red) trace element samples were collected using ''clean'' sampling tec hniques from four vertical profiles in the eastern Atlantic Ocean on t he first IOC Trace Metals Baseline expedition. The analytical results obtained by 9 participating laboratories for Mn, Fe, Co, Ni, Cu, Zn, C d, fb, and Se on samples from station 4 in the northeast Atlantic have been evaluated with respect to accuracy and precision (intercomparabi lity). The data variability among the reporting laboratories was expre ssed as 2 X SD for a given element and depth, and was comparable to th e 95% confidence interval reported for the NASS seawater reference sta ndards (representing analytical variability only). The discrepancies b etween reporting laboratories appear to be due to inaccuracies in stan dardization (analytical calibration), blank correction, and/or extract ion efficiency corrections. Several of the sampling bottles used at th is station were not adequately pre-cleaned (anomalous Pb results). The sample filtration process did not appear to have been a source of con tamination for either dissolved or particulate trace elements. The tra ce metal profiles agree in general with previously reported profiles f rom the Atlantic Ocean. We conclude that the sampling and analytical m ethods we have employed for this effort, while still in need of improv ement, are sufficient for obtaining accurate concentration data on mos t trace metals in the major water masses of the oceans, and to enable some evaluation of the biogeochemical cycling of the metals.