摘要：The concentration of PCB, Hg, Cd, As, Cu, Pb and Ni in the estuarial sediments of the rivers in Nagoya city were determined. The concentration of PCB ranged from 0.25 to 26.6 ppm and of the heavy metals exceeded those of the less polluted river sediments. Thus these sediments examined showed to be highly polluted by man's activities. The sediments were separated into 6 fractions of 500, 149, 105, 74, 62 and 62 μ>sizes by wet sieving analysis. The 149 μ fractions were composed of sand and coarse organic debris. In certain case, the amount of 149μ fraction exceeded that of 62 μ>fraction. The concentrations of PCB in the 149 μ fractions were higher than those in the 62 μ>fractions. However, in case of the sediment rich in gravel and sand, the reverse trend was recognized. The concentrations of heavy metals tended to be lower in the 149 μ fractions than 62 μ>fractions. These trends would indicate that PCB has a greater affinity for the coarse organic debris than the heavy metals. It was suggested that the distribution percentages of PCB and heavy metal contents to 149 μ fraction would depend on the qualitative and quantitative differences in the composition of the fraction. The floatabilities of sediments were examined in relation to the aggregate size distributions. It was confirmed that sediments rich in 149μ fraction composed of greater amounts of coarse organic debris or rich in the fine fraction of 62 μ>gave a large amount of suspended solids by agitation. In these cases, about 50% of PCB contained in the sediments were distributed into the suspended solids.
