| 外源输入对底泥疏浚新生表层磷恢复及迁移的影响 |
| 摘要点击 1911 全文点击 658 投稿时间：2019-01-25 修订日期：2019-03-07 |
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| 中文关键词 太湖 疏浚 泥水界面 磷 外源颗粒物输入 |
| 英文关键词 Taihu Lake dredging sediment-water interface phosphorus external particulate matter input |
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| 中文摘要 |
| 外源输入对底泥疏浚新生表层磷恢复及迁移转化的影响尚不清楚，阐明该问题对于底泥疏浚实施后流域尺度上的外源控制及管理具有重要的意义.本研究以太湖梅梁湾沉积物为研究对象，采用野外原位模拟疏浚的方法研究在有无外源颗粒物输入条件下，疏浚前后新生泥水界面磷的迁移转化过程，并探讨疏浚对内源磷释放的控制效果.结果表明，疏浚后阻止外源颗粒物输入对沉积物总磷（TP）和总氮（TN）的控制产生着积极的影响；疏浚显著降低了表层沉积物潜在可移动磷的含量，有外源颗粒物输入组潜在可移动态磷（Mobile-P）含量显著高于无外源组，变化的Mobile-P以铁结合态磷（Fe-P）为主，有机磷（Org-P）次之，弱结合态磷（Lb-P）含量较低不足总磷的1‰；实验210d后，有外源颗粒物输入疏浚组间隙水PO43--P浓度低于未疏浚组，无外源疏浚组显著低于未疏浚组（P<0.05）；无外源疏浚组间隙水PO43--P浓度保持着较低的水平，其余组间隙水中PO43--P浓度呈现先增加后减小的趋势，间隙水PO43--P浓度与其对应分层沉积物中Fe-P含量显著正相关；冬春季间沉积物的源-汇功能发生了转变，沉积物对上覆水由汇转变成为源；疏浚措施降低了底泥内源磷释放速率，可有效控制其内源磷释放，阻止外源颗粒物输入对疏浚控制内源磷负荷起到了较好的促进作用. |
| 英文摘要 |
| The effect of external pollution inputs on phosphorus recovery, transport, and transformation in newborn surface layers from sediment dredging remains unclear. Clarifying this issue is important for the control and management of external pollution loads at the watershed scale, particularly after the implementation of sediment dredging activities. In this study, sediments in Meiliang Bay of Lake Taihu were investigated. In-situ dredging simulation was used to study the transport and transformation of phosphorus at the sediment-water interface, before and after dredging, with either external or non-external particulate matter inputs, and to explore the effect of dredging on phosphorus release as part of internal loading. The results showed that limiting the inputs of external particulate matter and dredging had positive impacts on the control of TP and TN in the sediments. Dredging significantly reduced the content of potentially mobile phosphorus (Mobile-P) in surface sediments. Iron-bound phosphorus (Fe-P) was the first main component of the reduced Mobile-P and Organic phosphorus (Org-P) was the second. The content of Loose-bound phosphorus (Lb-P) was less than 1‰ of the total phosphorus. After 210 days of the experiment, the concentration of PO43--P in the pore water of the dredged treatment was lower than that of the undredged treatment, and this difference was more pronounced without external particulate matter input. Furthermore, the concentration of PO43--P in the pore water of the dredged treatment (without external particulate matter input) was maintained at a low level, while this first increased and then subsequently decreased for the other treatments. The concentrations of PO43--P in pore water were positively correlated with Fe-P in the corresponding sediment layers. Source-sink transition took place between winter and spring, leading to the switch in sediment functioning as a sink to a source. The results indicated that dredging could reduce the release rate of internal phosphorus from sediments. Furthermore, limiting the input of external particulate matter plays an important role in facilitating the control of internal phosphorus loading by dredging. |
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