Indium concentration in Pacific seawater

The concentration of indium in the seawaters of the western North Pacific was measured by using isotope dilution inductively coupled plasma mass spectrometry (ID-ICPMS). The data suggest a surface maximum and the profiles show a possible decrease with depth. The measured concentrations of indium range from 0.047 to 0.155 pmol/kg and are almost three orders of magnitudes lower than those reported for the North Pacific by Chow and Snyder [1969]. We believe that the earlier data reflect experimental artifacts. Our data are also lower by about one order of magnitude than those in the North Atlantic reported by Matthews and Riley [1970]. The possibility exists that their data also suffered from contamination problems. It is also likely that the concentration of indium in the Atlantic is indeed significantly higher than those in the Pacific due to the difference in the atmospheric input if indium behaves like Al. Redetermination of the Atlantic samples is essential to resolve the two possibilities.