1 Center for Nuclear Technologies, Technical University of Denmark2 Radioecology and Tracer Studies, Center for Nuclear Technologies, Technical University of Denmark3 Lamont-Doherty Earth Observatory4 Universidad Autonoma de Barcelona5 International Atomic Energy Agency6 Bundesamt für Seeschifffahrt und Hydrographie7 Korea Ocean Research and Development Institute
As part of the GEOTRACES Program, six laboratories participated in an intercalibration exercise on several anthropogenic radionuclides of interest. The effort was successful for 239,240Pu activity, 240Pu/239Pu isotope ratio, and 137Cs activity measured in filtered seawater samples from the Bermuda Atlantic Time Series station (BATS) and a site on the continental slope of the Northeastern U.S. A limited number of analyses were reported for 237Np, 241Am, 90Sr, and 238Pu in filtered seawater. Intercalibration of any of the isotopes of interest in filtered particulate matter was unsuccessful due to insufficient size of the samples distributed. Methods used were based on traditional radio-counting techniques and inductively coupled plasma mass spectrometry (ICP-MS). Although the majority of analyses were performed on samples ≥ 60 L, one lab demonstrated the ability to analyze several of the anthropogenic radionuclides on 10-20 L sample volumes using ICP-MS.