蓄水期三峡水库香溪河沉积物-水系统营养盐分布特征  

Nutrient Distribution Characteristics of the Sediment-water System in the Xiangxi River During the Impoundment of TGR

作　　者：苏青青[1,2] 刘德富[3] 纪道斌[1,2] 宋林旭[1,2] 崔玉洁[1,2] 李欣[1,2] 陈秀秀[4] 刘心愿 SU Qing-qing1,2, LIU De-fu3 , JI Dao-bin1,2 , SONG Lin-xu1,2, CUI Yu-jie1,2, LI Xin1,2, CHEN Xiu-xiu4, LIU Xin-yuan1,2(1. College of Hydraulic ＆ Environmental Engineering, China Three Gorges University, Yichang 443002, China; 2. Engineering Research Center of Ecoenvironment in Three Gorges Reservoir Region, Ministry of Education, Three Gorges University, Yichang 443002, China; 3. Hubei Key Laboratory of Ecological Restoration of River-lakes and Algal Utilization, Hubei University of Technology, Wuhan 430068, China; 4. Water Authority of Xuanzhou District, Xuancheng 242000, Chin)

机构地区：[1]三峡大学水利与环境学院,宜昌443002 [2]三峡大学三峡库区生态环境教育部工程研究中心,宜昌443002 [3]湖北工业大学,河湖生态修复与藻类利用湖北省重点实验室,武汉430068 [4]宣州区水务局,宣城242000

出　　处：《环境科学》2018年第5期2135-2144,共10页Environmental Science

基　　金：国家自然科学基金重大计划项目(91647207);国家自然科学基金项目(51509086); 国家国际科技合作项目(2014DFE70070); 国家水体污染控制与治理科技重大专项(2014ZX07104-005-02); 国家重点研发计划项目(2016YFC0402204)

摘　　要：为研究蓄水期香溪河沉积物-水系统中氮磷营养盐的分布特征,于2016年在香溪河布点采样,分析沉积物-水系统氮、磷及有机质含量,探讨沉积物间隙水和上覆水营养盐"源-汇"特征,并对采样点位进行了聚类分析.结果表明,沉积物中ρ(TN)在河口处含量较高,在中下游区域较接近;ρ(TP)在上游区域明显高于中下游及河口;ρ(O.M.)呈现下游高上游低的分布特征,且各采样点在深度10cm的范围内,ρ(O.M.)的最大值超过了临界点(1.5%),存在一定的释放风险.上覆水的分布上,ρ(DTN)和ρ(DTP)均在干支流交汇处最大,且ρ(DTN)从河口至上游沿程递减,ρ(DTP)沿程变化不大,而间隙水中ρ(DTN)和ρ(DTP)的分布和上覆水体相反,在上游处最大,并从上游向河口处递减.研究期间5个采样点位的DTN、NH_4^+-N、DTP(除CJ点位外)均以"源"的方式向上覆水释放营养盐,而NO_3^--N和PO_4^(3-)-P则是一部分点位呈现为"源",一部分点位呈现为"汇",且氮素的"源-汇"过程较磷素更为强烈,这是因为蓄水期底部的氧化环境和干流水体的倒灌潜入深度和方式差异所致.结合聚类分析结果发现对于沉积物-水系统,CJ、1号、2号采样点特征相近,而3号和4号采样点特征相近.This study characterizes the nutrient distribution of the sediment-water system in the Xiangxi River（ XXR） during the impoundment of the Three Gorges Reservoir（ TGR）. In 2016,the research group obtained samples in the Xiangxi River,analyzed the distribution of nitrogen,phosphorus,and O. M.（ organic matter） in the sediment-water system,explored the characteristics of＂source-sink＂between the interstitial water and overlying water,and carried out a cluster analysis for the sampling sites. The results showed that ρ（ TN） in the sediments was higher than in the estuary,and the ρ（ TN） was close to that in the middle and downstream samples of the river. The ρ（ TP） in the upstream sample was the highest of all sites, ρ（ O. M.） presented low distribution characteristics in the downstream,and the maximum value of ρ（ O. M.） exceeded the critical point（ 1. 5%） within a depth of 10 cm,and there was a certain risk of release. For the distribution in the overlying water,ρ（ DTN） and ρ（ DTP） were the largest in the estuary,ρ（ DTN） decreased from the estuary to the upstream,and ρ（ DTP） did not change along the river. During the study,DTN,NH4~＋-N,and DTP in all sites（ except CJ point） were released as nutrients to the overlaying water as the＂source,＂but some points for NO3^--N and PO4^（3-）-P presented as ＂sources,＂and some of them presented as ＂sinks. ＂The ＂source-sink＂process of nitrogen was stronger than that of phosphorus. This was due to the difference between the oxidation environment at the bottom of the XXR and the stream flow backward depth of the Xiangxi bay during impoundment. Based on the results of a cluster analysis,the characteristics of CJ,1,and 2 indicated similar sediment-water systems,while the characteristics of 3 and 4 were similar.

关 键 词：三峡水库 香溪河 蓄水期 沉积物-水系统 氮磷营养盐 

分 类 号：X524[环境科学与工程—环境工程]