Evaluation of in situ capping with clean soils to control phosphate release from sediments.
Evaluation of in situ capping with clean soils to control phosphate release from sediments.
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DOI：
10.1016/j.scitotenv.2012.08.053
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发表时间：
2012-11
期刊：
影响因子：
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通讯作者：
Di Xu;S. Ding;Qin Sun;Ji-cheng Zhong;Wei Wu;Fei Jia
中科院分区：
文献类型：
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作者：
Di Xu;S. Ding;Qin Sun;Ji-cheng Zhong;Wei Wu;Fei Jia
在封顶18个月后，对太湖一个富营养化海湾的沉积物进行了清洁土壤原位封顶，以控制沉积物中磷的释放。用高分辨率透析法(HR-PEEPER)和氧化锆膜扩散梯度法(Zr-Oxid DGT)测定了天然沉积物和盖层沉积物中溶解活性磷酸盐(DRP)的浓度。用改进的朗缪尔模型进一步研究了这些沉积物的吸附等温线。结果表明，封顶后孔隙水中DRP浓度较低，沉积物补给较少，以维持孔隙水DRP浓度。封顶处理后上覆水的计算通量大约是天然沉积物的一半，这意味着封顶减少了沉积物中磷酸盐的释放。覆盖后沉积物的低补给量进一步表现为较大的分配系数(Kp)和较大的吸附容量(Qmax)，而零平衡浓度(EPC0)与自然沉积物相似。较大的Kp和Qmax归因于封顶引入了较高的活性Fe和Al，表明磷酸盐与活性Fe和Al的结合在降低磷的内部负荷方面起着关键作用。
Evaluation of in situ capping with clean soils to control phosphate release from the sediments of a eutrophic bay in Lake Taihu was performed after 18months of capping. The concentrations of dissolved reactive phosphate (DRP) in pore waters and DRP resupply from native sediments and capped sediments were determined using high-resolution dialysis (HR-Peeper) and a Zr-oxide diffusive gradients in thin films (Zr-oxide DGT) technique. The adsorption isotherm of these sediments was further investigated using a modified Langmuir model. The results showed low concentrations of DRP in pore waters with a low resupply from the sediments for sustaining pore water DRP concentration after capping. The calculated flux to the overlying water following the capping treatment was approximately half of that for the native sediments, implying that the capping reduced the release of phosphate from the sediments. The low resupply of the sediments after capping was further demonstrated by larger partitioning coefficient (Kp) values and greater adsorption capacity (Qmax) values, while zero equilibrium concentrations (EPC0s) were similar to those in native sediments. The larger Kpand Qmaxwere attributed to higher active Fe and Al introduced by the capping, indicating that the binding of phosphate onto the active Fe and Al played a critical role in reducing the internal loading of phosphorous.