Abstract
Concentration of heavy metal (trace chalcophile elements) in the bottom sediment of the Watarase River, which has been notorious for the pollution problem caused by the copper mine, was determined and the behaviour of these elements in the riverbed was also examined. The results were as follows ;
1. Heavy metal concentrations in the bottom sediment were extreamly high as compared with those of other typical rivers in Japan.
2. The heavy metals originated from the mine drainage might flow down together with the suspended substances at the time of flooding.
3. The ratios of each metal concentration in the bottom sediment depends upon the concentration of each metal in suspended substances at the time of flooding.
4. The rapid decrease in the slope of riverbed around mid-stream accelerate the precipitation of suspended substances and affects metal concentration ratios in the bottom sediment.
