Organically-bound copper in lake and river waters in Japan

Organically-bound copper, organic matter concentrations and molecular weight of the organic matter in lake and river waters at Hokkaido in Japan were measured. The interaction between copper and the organic matter was also investigated by using Sephadex gel. The ratio of organicallybound copper to total copper was 10–70%. There was no relationship between the copper complex and the organic matter. From thermodynamic calculation, it was concluded that the variation of the ratio from 10 to 70% depended on the variation of stability constant of copper with the organic matter. The organic matter has molecular weight of 300–700 which resembles fulvic acid originating in river water.