Erratum: GEOTRACES radium isotopes interlaboratory comparison experiment Academic Article uri icon


  • In anticipation of the international GEOTRACES program, which will study the global marine biogeochemistry of trace elements and isotopes, we conducted a multi-lab intercomparison for radium isotopes. The intercomparison was in two parts involving the distribution of: (1) samples collected from four marine environments (open ocean, continental slope, shelf, and estuary) and (2) a suite of four reference materials prepared with isotopic standards (circulated to participants as 'unknowns'). Most labs performed well with 228Ra and 224Ra determination, however, there were a number of participants that reported 226Ra, 223Ra, and 228Th (supported 224Ra) well outside the 95% confidence interval. Many outliers were suspected to be a result of poorly calibrated detectors, though other method specific factors likely played a role (e.g., detector leakage, insufficient equilibration). Most methods for radium analysis in seawater involve a MnO2 fiber column preconcentration step; as such, we evaluated the extraction efficiency of this procedure and found that it ranged from an average of 87% to 94% for the four stations. Hence, nonquantitative radium recovery from seawater samples may also have played a role in lab-to-lab variability.
  • In our original paper, Charette, M. A., H. Dulaiova, M. E. Gonneea, P. B. Henderson, W. S. Moore, J. C. Scholten, and M. K. Pham. 2012. GEOTRACES radium isotopes interlaboratory comparison experiment. Limonol. Oceanogr.: Methods 10:451, the incorrect headers were used for Table 9.

publication date

  • August 2012