Abstract
Field observations were carried to investigate effects of suspended sediment on the behavior of dissolved phosphate in estuary of the Ishikari river during the snowmelt season in 2004. Suspended sediment was sampled during the snowmelt flood at Sapporo Oh-hashi, at the same time water quality was observed in the coastal area near the river mouth. The phosphorus chemical combined forms of the samples were analyzed, and experiments were conducted to study variation of the release of phosphate to salinity and pH change. Behavior of the phosphate adsorption from the suspended sediment was followed the Langmuir relation in each salinity and pH condition. At the flood dissolved phosphate concentration changed at the estuary, and was highest at lkm from the river mouth. And the behavior of the dissolved phosphate in estuary was explained by the Langmuir relation.
