摘要：

The present study aims to further reveal the environmental behavior of mercury on sediments surface.Effects of particlesizes,pH and concentrations of dissolved organic matter(DOM) on mercury adsorption and desorption to the surface of sediments in the Songhua River were investigated by simulation experiments.A distinct variety of absorption ability among sediments with different particle-sizes was observed.Under this experimental condition,the absorption ability increased inversely with particle-size of sediments.In all absorption systems,mercury adsorption was enhanced when pH increased from 3.5 to 4.5,while mercury adsorption was inhibited significantly with the increasing of pH when pH values were above 4.5.With the increasing of pH values,the desorption of mercury presented a decreasing-increasing trend,the minimum desorption occurred at pH 5.Citric acid inhibited the mercury adsorption,and the intensity was correlated with mercury concentrations.Effects of citric acid on desorption of mercury were also apparently.With the increasing of citric acid concentrations,its effect on desorption presented a trend as enhanced-inhibited-steadied.Therefore,the above factors affected the mercury adsorption and desorption obviously,and it was necessary to take these factors into consideration in conducting the rivers'mercury control and dealing with a sudden pollution incident.

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