| 新水沙条件下长江中下游干流水体总磷时空变化分析 |
| 摘要点击 1716 全文点击 705 投稿时间：2020-05-11 修订日期：2020-06-16 |
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| 中文关键词 新水沙条件 长江中下游 干流 总磷 时空变化 |
| 英文关键词 new water and sand conditions the middle and lower reaches of the Yangtze River mainstem total phosphorus spatial and temporal variations |
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| 中文摘要 |
| 长江干流三峡及上游水库群陆续建成运行后，中下游干流水体已形成新的水沙条件，其对水体磷含量的影响备受关注.为此，研究了新水沙条件下中下游干流总磷浓度的时空分布特征.结果表明：①三峡蓄水后，长江中下游干流水体TCP（澄清30min样品）浓度基本在0.10~0.15 mg·L-1之间变动，在时间尺度上总体呈先上升后降低趋势，在空间尺度上沿程呈现升高趋势；水体中溶解态总磷（TDP）浓度随时间推移缓慢升高.②水体中可沉降固体对不同江段水体中磷含量存在不同程度影响，南津关、汉口和吴淞口下23 km这3个断面TCP/TP比值中位值分别为0.900、0.720和0.609，从上游到下游依次降低；水体中溶解态总磷（TDP）占总磷（TP）比例沿程呈下降趋势，而颗粒磷（TPP）占总磷（TP）比例沿程呈上升趋势，南津关、汉口、吴淞口下23 km等3个断面TPP/TP比值中位值分别为0.439、0.567和0.738.③按照《地表水环境质量标准》（GB 3838-2002）要求，以TCP浓度进行水质评价，评价结果显示长江中下游干流水质总体良好.但若考虑水体中可沉降固体影响，以水体总磷（TP）浓度进行评价，会得出相对较差的结果，尤其是在靠近河口段.④长江中下游干流主河道靠上游河段不同监测断面内部各测线、测点磷浓度差异较小，河口附近则差异明显.⑤长江中下游干流城市江段近岸水域水体中TCP浓度明显高于相应河段主河道常规监测结果，局部河段存在明显岸边污染带. |
| 英文摘要 |
| After the completion of the Three Gorges Reservoir and the upstream reservoir group of the Yangtze River, new water and sediment conditions appeared in the middle and lower reaches of the Yangtze River, and its influence on the phosphorus concentrations in water has attracted much attention. Therefore, the spatial and temporal distributions of total phosphorus (TP) concentrations in the middle and lower reaches of the mainstem under the new water and sediment conditions were studied. The results show that:① after the construction of the Three Gorges Reservoir, the concentrations of TCP (samples were allowed to settle for 30 min) in the middle and lower reaches of the Yangtze River fluctuates between 0.10 and 0.15 mg·L-1, and generally increased during 2004-2010 and then decreased during 2014-2019, and increases along the flow direction. The concentrations of dissolved total phosphorus (TDP) have slowly increased with time. ② The settleable solids influence the phosphorus content to varying degrees. The median values of TCP/TP ratio in Nanjinguan, Hankou, and 23 km below Wusongkou, are 0.900, 0.720, and 0.609, respectively, which decreases successively from upstream to downstream. The proportion of TPP (total particulate phosphorus)/TP shows an increasing trend along the flow direction. The median values of TPP/TP ratios in Nanjinguan, Hankou, and 23 km below Wusongkou were 0.439, 0.567, and 0.738, respectively. ③ According to the "Environmental quality standard for surface water GB 3838-2002", the water quality was assessed using TCP concentrations, and the assessment results showed that the water quality of the middle and lower reaches of the Yangtze River was generally good. However, considering the influence of settleable solids, the water quality categories assessed based on TP concentrations would be worse, especially near estuaries. ④ In the middle and lower reaches of Yangtze River, there is little difference in the phosphorus concentration of different monitoring sites in the upper section of main stream; however, the difference is obvious near the estuary. ⑤ The concentration of TCP in the coastal waters of the urban river section of the middle and lower reaches of the Yangtze River is significantly higher than that of the main channel, and there are obvious coastal pollution zones in the coastal waters of the urban river section. |
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