| 摘要: |
| 磷（P）是长江流域备受关注的污染物。乌江是长江八大支流之一，位于三峡水库近库尾江段。武隆断面是乌江入长江控制断面。研究了1998 ~ 2019时期武隆断面径流量、悬浮泥沙浓度（SS）与输沙量、磷浓度与通量[分总磷（TP）、溶解态磷（DP）和颗粒态磷（PP）]年际变化及季节特征，并基于河流基流分割原理对磷的来源进行了解析。结果表明，（1）1998 ~ 2019年，乌江武隆断面径流量在一定幅度内上下波动，而悬浮泥沙浓度和输沙量下降剧烈。（2）22 a（年）来，乌江TP和DP浓度与通量总体上呈先升高后下降趋势，2009 ~ 2013为磷污染巅峰期，TP和DP浓度与通量远高于其它时期。（3）2007年是一个重要的时间节点，该节点前，TP的赋存形态以颗粒态为主，颗粒态磷在总磷中的占比均值为65%；该节点后，TP的赋存形态转变为以溶解态为主，颗粒态磷占比均值下降为16%，相应地，溶解态磷占比由35%上升为84%。水沙条件改变是磷形态发生显著变化的主要驱动力，磷污染程度亦是磷形态变化的重要影响因素。（4）磷通量在年内的季节分布发生了显著变化，丰水期磷通量减少，枯水期磷通量增加。（5）1998 ~ 2012、2009 ~ 2013和2014 ~ 2019时期点源负荷占比分别为23.5%、36.8%和62.1%，呈增加趋势。（6）建议制定适宜的总磷控制目标，结合目前所存在的磷污染风险点，进一步强化监管，侧重源头治理。 |
| 关键词: 乌江 磷 通量 形态 来源 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金长江水科学研究联合基金(U2240213)；三峡工程生态与环境监测合同项目(JJ[2015-008], JJ[2015-047], JJ[2016-012]) |
|
| Variation of Phosphorus Concentration and Flux at Control Section of Wujiang River entering the Yangtze River and Source Apportionment |
|
LOU Bao-feng, Huang Bo, Huang Xiaolong, Zhuo Hai-hua
|
|
Changjiang River Basin Ecology and Environment Monitoring and Scientific Research Center,Changjiang River Basin Ecology and Environment Administration,Ministry of Ecology and Environment
|
| Abstract: |
| Phosphorus (P) is a pollutant of great concern in the Yangtze River basin. Wujiang River is one of the eight major tributaries of the Yangtze, and the entrance is located downstream the tail of the Three Gorges Reservoir. The Wulong section is the control section of the Wujiang River entering the Yangtze. The interannual changes and seasonality of runoff, and concentration and flux of suspended sediment (SS) and P [including total phosphorus (TP), dissolved phosphorus (DP), and particulate phosphorus (PP)] at the Wulong section during 1998 - 2019 were studied. Based on the principle of river base flow segmentation, P loads from the point sources and non-point sources were analyzed. The results indicate that from 1998 to 2019, the runoff fluctuated up and down within a certain range, while SS concentration and flux decreased sharply. (2) In the past 22 years, the concentration and flux of TP and DP have shown an overall trend of firstly increasing and then decreasing. Extraordinarily high TP and DP concentrations and flux were observed during 2009 - 2013 called the peak P pollution period. (3) 2007 is a key time node, before which P was mainly in particulate form, with the average percentage of 65% of TP, and after the node, P became mainly in dissolved form, and the average percentage of PP decreased to 16%. Variation in water and sediment conditions is the main driver for the significant change in P form, and the degree of P pollution is another influencing factor. (4) There is significant difference in the seasonal distribution of P flux compared to before, showing a decrease in the wet season and an increase in the dry season. (5) The percent of point source load in the period of 1998 - 2012, 2009 - 2013, and 2014 - 2019 was 23.5%, 36.8%, and 62.1%, respectively, indicating an increasing trend. (6) It is recommended to establish appropriate TP control goals, pay much attention to the existing P pollution risk points, and strengthen supervision and source control. |
| Key words: Variation of Phosphorus Concentration and Flux at Control Section in Wujiang River Entering the Yangtze River and Source Apportionment |
