ABSTRACT

Partitioning of cadmium into five fractions (1M CH₃COONH₄ soluble, 1M CH₃COOH soluble, 30% H₂O₂ soluble, 0.04M NH₂OH·HCl soluble and silsicate lattice fractions) of core sediments from the Osaka Bay has been determined by using selective chemical leaching technique. In addition to cadmium, partitioning of copper, manganese and iron has been also examined as a control. Large amounts of heavy metals (cadmium and copper) are contained in the upper parts of the sediment. The cadmium and copper contents of the sediment are relatively large in the Bay near the industrial area. Cadmium is distributed mainly in 30% H₂O₂ soluble and silicate lattice fractions. Cadmium leached into 30% H₂O₂ solution may have been partly derived from ferro-manganese oxide fraction as well as pyrite fraction of the sediment. The amount of cadmium contained in silicate lattice fraction of the sediment in the Osaka Bay is larger than that of silicate rocks collected from land area. 1 M CH₃COOH soluble fraction is important for the cadmium content near the surface portion of the sediment. Cadmium dissolved in 1 M acetic acid solution may have been partly derived from acid soluble sulfide fraction of the sediment. Some of cadmium contained in 1 M CH₃COOH soluble fraction may have heed derived from ferro-manganese oxide fraction of the sediment.