The chemical behavior of inorganic elements in seawater

The chemical behavior of radioactive cerium and cobalt in seawater was studied on the basis of chemical equilibrium between those elements and major anions or amino acids present in seawater. The stability constants of inorganic complexes of 144Ce were determined by using ion exchange batch method with Dowex 50W-X8 and -4. The abundance ratios of 144Ce was calculated with the stability constants obtained in this experiment and the most dominant species was Ce(OH)3. The stability constants of 60Co with major anions as well as amino acids were determined and the abundance ratios of chemical species of 60Co was determined as well. A small fraction of amino-cobalt was formed in seawater and large part of 60Co introduced into seawater remained in the form of inorganic complexes. Redox change of 125I in the seawater was also studied. Radioactive iodine-125 was inoculated into the aquarium in which fish or seaweeds was held. Both reduction and oxidation reaction occurred in the aquarium containing living organisms, while only oxidation reaction proceeded in the aquarium without holding living organisms. (author)