赣南桃江河表层沉积物重金属内源释放规律

Endogenous release rules of heavy metals from surface sediments of Taojiang River in Southern Jiangxi

桃江河流经赣南矿区,河中重金属沉积严重。为探讨桃江表层沉积物中重金属Cu、Zn与As的释放规律,在pH、温度、盐离子强度、NH4+及水体扰动强度5种不同因子控制下完成单因子释放试验,并在控制温度、pH、NH4+、盐度条件下进行正交实验。单因子试验结果表明:Cu、Zn与As在酸性条件(pH=2~6)释放率大于碱性条件(pH=8);3种重金属在高温(26℃)条件下的释放率明显高于低温(9℃)条件下的释放率,释放率与盐离子强度、NH4+、水体扰动强度均呈正相关关系。正交释放试验结果表明:各因子对重金属Cu和As释放量影响大小顺序为:温度>pH>NH4+>盐度,对Zn释放量影响大小为:pH>NH4+>盐度>温度。

The sedimentation situation of heavy metals is serious in Taojiang River which passes through Southern Jiangxi mining area.In order to explore the release rules of heavy metals Cu,Zn and As in the surface sediments of Taojiang River,a single factor release test was completed under the control of five different factors:pH,temperature,salt ion intensity,NH4+and water disturbance intensity,and the orthogonal experiment was conducted under controlled temperature,pH,NH4+,and salinity conditions.The results of single-factor experiment show that the release rates of heavy metals Cu,Zn and As are higher than alkaline conditions(pH=8)under acidic conditions(pH=2~6);The release rate of the three heavy metals at high temperature(26℃)is significantly higher than that at low temperature(9℃).The release rates of three heavy metals are positively correlated with salt ion strength,NH4+and water disturbance intensity.The results of orthogonal release test show that the effect of each factor on the release of heavy metals Cu and As is in the order of temperature>pH>NH4+>salinity,and the effect of each factor on the release of Zn is pH>NH4+>salinity>temperature.