摘要
城市河道底泥淤积不仅影响城市泄洪,而且还会成为河流的内源污染。因此,底泥疏浚是当前城市河流生态治理的重要途径。受底泥污染状态、底泥运输及堆放处理成本的影响,确定适宜的底泥疏浚深度,既可有效地削减河道内源污染,亦可减少疏浚成本,是当前底泥疏浚治理迫切需要掌握的信息。为此,本研究以伊通河长春市城区段为对象,在南绕城高速至杨家巍子大桥约15 km的河段上设立了6个采样点,每个采样点分别采集上层(0~20 cm)、中层(20~40 cm)和下层(40~60 cm)的底泥,以最上游采样断面水体作为上覆水,进行室内释放模拟实验。通过实验前后对底泥中有机质、总氮、氨氮和速效磷等指标的释放量测试与分析,结果发现:伊通河城区段底泥的有机质含量沿水流方向降低,且主要积累在上层底泥;底泥中总氮的分布较为均匀,速效磷的分布多样性较大;上游和中游底泥均会向上覆水体中释放有机质,中层和下层底泥的释放量较低;底泥在与上覆水体接触时是氮元素的源,中层底泥氮的释放量最低(平均0.23 g/kg);上游上层、中游和下游中层底泥速效磷的释放量最低(分别为9.68、12.20和14.34 mg/kg)。综合考虑底泥污染状态,建议伊通河城区段底泥的适宜疏浚深度为20~40 cm,这一结果为伊通河城区段底泥的生态疏浚提供了重要的数据支持,也为其他河流底泥疏浚深度的确定提供了重要借鉴。
Sediment deposition in urban rivers not only affects urban flood discharge,but also becomes the endogenous pollution of rivers.Therefore,sediment dredging is an important way for ecological management of urban rivers.Affected by the state of sediment,the cost of transportation and disposal,determining the appropriate depth of dredging can both effectively reduce the endogenous pollution and the cost of dredging,which is urgently needed information for current sediment dredging management.This study takes the Changchun City section of the Yitong River as an object,and sets up six sampling points on the 15 km section from the South Ring Expressway to the Yangjiaweizi Bridge.The upper layer(0~20 cm),middle layer(20~40 cm)and lower layer(40~60 cm)of sediment were collected at each sampling point,and the water at the upstream sampling section was used as the overlying water for laboratory release simulation experiment.Through the detection of chemical indicators of sediment before and after the experiment,analysis of the release on organic matter,total nitrogen,ammonia nitrogen and available phosphorus revealed that:Organic matter in sediment decreased along the flow direction and mainly accumulated in the upper layer;The distribution of total nitrogen is relatively uniform,but available phosphorus is diverse;both the upstream and midstream sediment released organic matter to the overlying water,and the release of the middle and lower layers is low;sediment is the source of nitrogen,and the release in the middle layer is the lowest(mean 0.23 g/kg);the release of available phosphorus in the upper layer of the upstream and the middle layer of the midstream and downstream is the lowest(9.68,12.20 and 14.34 mg/kg,respectively).Considering the pollution status of the sediment comprehensively,it suggests that the appropriate dredging depth of the Yitong River is 20~40 cm.This result provides important data support for the ecological dredging in the urban section of the Yitong River,and also provides an important reference for determining the sediment dredging depth of other rivers.
作者
梁佳文
阳涛
韩雪
姜海波
何春光
LIANG Jia-wen;YANG Tao;HAN Xue;JIANG Hai-bo;HE Chun-guang(State Environment Protection Key Laboratory of Wetland Ecology and Vegetation Restoration,Northeast Normal University,Changchun 130117,China;School of Life Science,Nanjing University,Nanjing 210023,China)
出处
《环境生态学》
2020年第11期81-90,共10页
Environmental Ecology
基金
吉林省科技厅科技攻关项目(20200503001SF)资助。
关键词
底泥
内源污染
疏浚深度
城市河段
伊通河
sediment
endogenous pollution
dredging depth
urban reach
Yitong river
