| 三峡库区沉积物秋末冬初的磷释放通量估算 |
| 摘要点击 4878 全文点击 2592 投稿时间：2012-06-11 修订日期：2012-10-20 |
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| 中文关键词 沉积物-水界面 正磷酸盐 Fick定律 释放通量 三峡水库 |
| 英文关键词 sediment-water interface phosphate Fick's Law releasing fluxes the Three Gorges Reservoir (TGR) |
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| 中文摘要 |
| 2010年11月~12月在三峡水库开展了沉积物内源负荷调查,对云阳等6个长江干流点和9条支流河口的沉积物-水界面正磷酸盐含量(PO43--P)进行了分析. 结果表明,支流上覆水和孔隙水中PO43--P含量略高于干流,其中支流孔隙水中的含量为9.59~29.79 μg·L-1,干流孔隙水中的含量为9.01~25.36 μg·L-1. 根据Fick第一定律公式得到郭家坝和小江河口为PO43--P的"汇",释放通量分别为-0.63 mg·(m2·a)-1和-0.60 mg·(m2·a)-1,其它区域的PO43--P均是由孔隙水向上覆水进行扩散,释放通量的范围为0.15~2.47 mg·(m2·a)-1. 假设分子扩算是沉积物营养元素迁移的主要途径,库区水体混合均匀,估算出沉积物孔隙水营养元素在沉积物-水界面的扩散迁移对上覆水体的影响程度较小,仅有-0.011%~0.098%. 目前三峡水库沉积物作为内源,释磷作用还未对水质产生较大影响,但不排除水库外部污染源得到控制后,三峡库区沉积物内源营养负荷的潜在释放风险. |
| 英文摘要 |
| In order to investigate the internal contamination load sources in the Three Gorges Reservoir (TGR), a field sampling campaign was carried out in November and December 2010. Phosphate contents (PO43--P) were determined in 6 mainstream and 9 estuary sediment cores of sediment-water interface in the TGR. The results showed that the PO43--P concentrations of pore water in sediments from tributaries and the corresponding overlying water were higher than those from the mainstream. The PO43--P contents in tributaries and mainstream ranged from 9.59-29.79 μg·L-1 and 9.01-25.36 μg·L-1, respectively. Based on calculations using the Fick's First Law, sediments located at GuoJiaba and Xiaojiang estuaries were the 'sink' of P, and the fluxes of sediment PO43--P were estimated to be -0.63 mg·(m2·a)-1and -0.60 mg·(m2·a)-1, respectively. In other areas, PO43--P diffused from the pore water to the overlying water, and the diffusive fluxes were in the range of 0.15-2.47 mg·(m2·a)-1. With the assumption that molecular diffusion was the main process by which nutrients were transported from the pore water to the overlying water and the water body in the TGR was evenly mixed, the contribution of sediment phosphorus to the water body was only -0.011-0.098%. So far, with the Three Gorges Reservoir sediments as the internal contamination load sources, the phosphorous release didn't significantly influence the water quality. The sediments in the TGR may be a large P source in a period of future time after the external P source is controlled efficiently. |
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