鉄剤散布による堆積物からの硫化物溶出抑制

抄録

The effect of iron and iron hydroxide on sedimentary hydrogen-sulfide release was studied with laboratory incubation method using intact sediment cores sampled from Mikawa Bay, Japan. As a preliminary investigation, the experimental setup was reassessed to clarify the effect of agitation of the overlying water on the material balances at the sediment-water interface. Laboratory incubation experiment using intact sediment cores was conducted varying the agitation intensity to monitor sedimentary oxygen demand. The results showed that sedimentary oxygen demand was positively affected by flow velocity. As such physical control is common mechanism for dissolved materials, we briefly summarize that the hydrodynamic control is indispensable to sediment-core-incubation procedure. Based on the preliminary investigation, the same experimental procedure was employed to investigate the effect of iron and iron hydroxide on sedimentary hydrogen-sulfide release. In the procedure, intact sediment cores were incubated under anoxic condition for 5 days with addition of iron and iron hydroxide powder on the sediment surface and hydrogen sulfide concentration in the overlying water was monitored. The results showed that sedimentary hydrogen-sulfide-release was clearly suppressed by addition of 1.55 mg/cm²-iron powder and of 1.38 mg/cm²-iron hydroxide powder, respectively. The experimental results were also compared with an existing numerical diagenetic-model and discussed.