Study on the chemical forms of radionuclides in seawater-III complexes of60Co with amino acids

Abstract

Stability constants were determined for60Co (II)-amino acid complexes in sodium perchlorate media at an ionic strength μ=0.67, using cation exchange resins. Stability constants were, for Co(II)-phenylalanine, log β1=4.4, log β2=8.2, log β3=11.7, for Co(II)-histidine, log β1=7.4. for Co(II)-valine, log β1=4.3, log β2=8.5, for Co(II)-proline, log β1=4.1, and for Co(II)-tyrosine, log β1=7.2, respectively. The abundance of Co(II)-amino acid complexes in seawater was calculated from these stability constants on the basis of chemical equilibrium, assuming the concentration of individual amino acid to be 10-7 to 10-8 mol l-1. It was inferred that the Co(II)-amino acid complexes are probably not formed abundantly in seawater while inorganic species of60Co(II) may still be dominant for a short period of time after discharge into seawater as liquid waste. © 1981 the Oceanographical Society of Japan.