摘要
为了了解清淤对水渠中沉积物与其上覆水界面氮扩散通量的作用,在洞庭湖区南汉垸的玉成电排渠、汉新排渠、永兴排渠和下新码头排渠中,分别设置采样点,于2017年11月15日(清淤前)和12月20日(清淤后),采集沉积物及其上覆水样品,测定水样的各项指标,并测定沉积物的含水量和孔隙率,计算沉积物间隙水与其上覆水中的氨氮和硝态氮浓度梯度;采用Fick定律,估算沉积物与上覆水界面的氮扩散通量,比较了清淤前后沉积物与上覆水界面氮扩散通量。研究结果表明,清淤后,玉成电排渠、汉新排渠、永兴排渠和下新码头排渠水体中的总氮质量浓度分别减小了2.05 mg/L、0.70 mg/L、0.72 mg/L和2.90 mg/L,氨氮质量浓度分别减小了1.41 mg/L、0.27 mg/L、0.69 mg/L和2.05 mg/L,总磷质量浓度分别减小了0.34 mg/L、0.13 mg/L、0.24 mg/L和0.22 mg/L,高锰酸盐指数和叶绿素a含量也都减小,透明度和溶解氧含量都增大,清淤明显改善了水渠水体的水质;清淤前后水渠中沉积物与其上覆水界面的氨氮扩散通量平均值分别为(5.09±3.01)mg/(m^2·d)和(-1.81±0.88)mg/(m^2·d),硝态氮扩散通量平均值分别为(1.14±0.88)mg/(m^2·d)和(-0.35±0.67)mg/(m^2·d);清淤前,沉积物是其上覆水中氨氮和硝态氮的源,清淤后其则是氨氮和硝态氮的汇;通过清淤可以明显减少南汉垸水渠沉积物中的内源氮的释放量。
In order to comprehend the role of dredging on nitrogen diffusion flux of interface between sediment and its overlying water,Yuchengdian drainage channel,Hanxin drainage channel,Yongxing drainage channel and Xiaxin wharf drainage channel in Nanhan Embankment in the Dongting Lake area were selected and the sampling sites were set in the four channels.The sediments and overlying water were sampled on November 15 and December 20,2017(before and after dredging).The indexes of water samples,moisture content and porosity of sediment were determined.And concentration gradient of ammonia nitrogen and nitrate nitrogen in the water and overlying water was calculated.Using Fick’s law was used to estimate the nitrogen diffusion flux of interface between sediment and its overlying water,and compared them before and after dredging.The results showed that contents of total nitrogen in the water of Yuchengdian drainage channel,Hanxin drainage channel,Yongxing drainage channel and Xiaxin wharf drainage channel were decreased 2.05 mg/L,0.70 mg/L,0.72 mg/L and 2.90 mg/L,and contents of ammonia nitrogen were decreased 1.41 mg/L,0.27 mg/L,0.69 mg/L and 2.05 mg/L,and contents of total phosphorus were decreased 0.34 mg/L,0.13 mg/L,0.24 mg/L and 0.22 mg/L after dredging.And permanganate indexes and Chlorophylla contents decreased,whereas the transparency and dissolved oxygen content increased.This implied that the dredging work improved the water quality in the ditches.The mean diffusion fluxes of ammonia nitrogen of interface between sediment and its overlying water in the ditches before and after dredging were(5.09±3.01)mg/(m^2·d)and(-1.81±0.88)mg/(m^2·d),whereas the mean diffusion fluxes of nitrate nitrogen were(1.14±0.88)mg/(m^2·d)and(-0.35±0.67)mg/(m^2·d),respectively.The sediment was the source of ammonia nitrogen and nitrate nitrogen in the overlying water before dredging,whereas the sink after dredging.Dredging work could reduce the release of endogenous nitrogen in the ditches of Nanhan Embankment.
作者
瞿畏
龚丽玲
邓征宇
余关龙
杨利平
杨楠
陈宏
李峰
QU Wei;GONG Liling;DENG Zhengyu;YU Guanlong;YANG Liping;YANG Nan;CHEN Hong;Li Feng(Changsha Environmental Protection College,Changsha 410004,Hunan,P.R.China;Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province,School of Hydraulic Engineering,Changsha University of Science&Technology,Changsha 410114,Hunan,P.R.China;China National Machinery Industry International Company Limited,Changsha 410007,Hunan,P.R.China;Key Laboratory of Key Technologies of Digital Urban-Rural Spatial Planning of Hunan Province,College of Architecture and Urban Planning,Hunan City University,Yiyang 413000,Hunan,P.R.China;Institute of Subtropical Agriculture,Key Laboratory of Agro-ecological Processes in Subtropical Region,Lake Dongting Station for Wetland Ecosystem Observation and Research,Chinese Academy of Sciences,Changsha 410125,Hunan,P.R.China)
出处
《湿地科学》
CSCD
北大核心
2020年第4期468-474,共7页
Wetland Science
基金
国家自然科学基金项目(51308068)
湖南省重点研发计划项目(2017SK2361和2018XK2009)资助。
关键词
氮扩散通量
沉积物
上覆水
界面
排渠
南汉垸
nitrogen diffusion flux
sediment
overlying water
interface
drainage channel
Nanhan Embankment
