引用本文: | 龚小杰,王晓锋,刘婷婷,袁兴中,孔维苇,刘欢.流域场镇发展下三峡水库典型入库河流水体碳、氮、磷时空特征及富营养化评价.湖泊科学,2020,32(1):111-123. DOI:10.18307/2020.0111 |
| GONG Xiaojie,WANG Xiaofeng,LIU Tingting,YUAN Xingzhong,KONG Weiwei,LIU Huan.Spatial-temporal characteristics of carbon, nitrogen and phosphorus and eutrophication assessment in a typical river of Three Gorges Reservoir under the development of field towns. J. Lake Sci.2020,32(1):111-123. DOI:10.18307/2020.0111 |
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流域场镇发展下三峡水库典型入库河流水体碳、氮、磷时空特征及富营养化评价 |
龚小杰1,2, 王晓锋1,2, 刘婷婷1,2, 袁兴中1,2,3, 孔维苇1,2, 刘欢1,2
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1.长江上游湿地科学研究重庆市重点实验室, 重庆 401331;2.重庆师范大学地理与旅游学院, 重庆 401331;3.重庆大学建筑城规学院, 重庆 400030
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摘要: |
流域场镇式发展是三峡地区城乡统筹发展的重要模式,通常形成河流两岸串珠状的场镇分布格局,这种人类活动的点状聚集特征对入库河流水环境的综合影响并不清楚.选择三峡库区流域场镇发展特征明显的黑水滩河及主要支流为研究对象,于2014年9月至2015年6月期间对流域内分布的主要场镇前后的水体进行碳、氮、磷浓度的监测分析,探讨场镇分布对流域水体生源要素时空格局的影响.研究结果表明,黑水滩河干、支流水体总有机碳(TOC)和溶解性有机碳浓度为4.5~39.2和3.2~31.4 mg/L,总氮(TN)、铵态氮和硝态氮浓度范围为1.12~6.96、0.87~5.00和0.073~0.881 mg/L,总磷(TP)、溶解性总磷和正磷酸盐浓度范围为0.078~0.454、0.049~0.310和0.025~0.222 mg/L,不同形态的碳、氮、磷含量变化幅度较大;黑水滩河干、支流流经不同场镇区前后,水体各形态碳、氮、磷浓度均不同程度增加(其中TOC、TN和TP的增幅范围分别为4.7%~61.3%、26.7%~144.7%和12.8%~50.7%),而在无场镇分布的干流河段,水体碳浓度变化不大,氮、磷浓度明显降低,表明水体生源要素的空间变异特征受到流域场镇分布格局与河流自净能力的双重影响,导致黑水滩河干流自上游向下游碳浓度呈“阶梯式”增长,氮、磷浓度呈“波动式”增长;相关分析显示,流域水体碳、氮、磷浓度均呈极显著的正相关关系,即场镇发展模式下河流水体污染物呈同步变化的趋势,表明山地河流流域内串珠状场镇发展模式导致从上游向下游水体污染物呈明显的累积效应,并进一步超出水体自净能力,造成下游水体恶化.河流碳、氮、磷浓度的季节变化主要受径流稀释作用影响,表现为夏秋季低、春季高的模式;富营养化综合指数表明,黑水滩河各监测断面全年属于富营养状态以上,表层水体氮污染严重,磷污染较轻;初步估算黑水滩河每年向三峡水库输入TOC、TN、TP通量达4057、1001和47 t,对三峡水库水环境安全具有严重威胁.三峡库区沿河串珠状场镇式发展形成了一种“点-面”双重特征的污染模式,未来河流水环境污染防控中应予以关注. |
关键词: 场镇发展 黑水滩河 碳、氮、磷 时空特征 富营养化评价 |
DOI:10.18307/2020.0111 |
分类号: |
基金项目:国家自然科学基金项目(41807321)、重庆市基础研究与前沿探索项目(CSTC2018JCYJAX0672)、重庆市教委科学技术研究项目(KJQN201800530)和重庆师范大学博士科研启动项目(17XLB023)联合资助. |
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Spatial-temporal characteristics of carbon, nitrogen and phosphorus and eutrophication assessment in a typical river of Three Gorges Reservoir under the development of field towns |
GONG Xiaojie1,2, WANG Xiaofeng1,2, LIU Tingting1,2, YUAN Xingzhong1,2,3, KONG Weiwei1,2, LIU Huan1,2
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1.Chongqing Key Laboratory of Wetland Science Research of the Upper Yangtze River, Chongqing 401331, P. R. China;2.College of Geography and Tourism, Chongqing Normal University, Chongqing 401331, P. R. China;3.Faculty of Architecture and Urban Planning, Chongqing University, Chongqing 400030, P. R. China
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Abstract: |
As an important urban and rural development model in the three gorges reservoir area, watershed field town development model along the river has been widely popularized, and brought a series of the complex influences of the point-like aggregation pattern for human activities on the river water environment. In this study, the Heishuitan River and its main tributaries, which are featured with obviously field town development in the basin, were selected to carry out an investigation regarding carbon, nitrogen and phosphorus concentrations in surface water from September, 2014 to June, 2015, for discussing the influence of field towns distribution on the temporal and spatial patterns of water biogenic element in the basin. Results showed that, the concentrations of TOC and DOC in the water of main stream and tributaries were 4.5-39.2 and 3.2-31.4 mg/L, and TN, NO3--N and NH4+-N were 1.12-6.96, 0.87-5.00 and 0.073-0.881 mg/L, while the ranges of TP, DTP and PO43--P concentrations are of 0.078-0.454, 0.049-0.310 and 0.025-0.222 mg/L. All of the biogenic elements in the water presents a significantly spatiotemporal variability. The concentrations of carbon, nitrogen and phosphorus increased in certain extent when the water flowed through different towns, with the increasing range of the TOC, TN and TP of 4.7%-61.3%, 26.7%-144.7% and 12.8%-50.7%, respectively. Meanwhile, the water flowed through non-town reaches, the carbon concentrations of the main stream had no significant changes, and nitrogen and phosphorus concentrations were significantly reduced, indicating that the spatial variation characteristics of water biogenic elements (C, N and P) were co-regulated by the distribution pattern of the watershed towns and its self-purification capacity, and resulting that the carbon concentrations in the main stream increased "stepwise" from the upstream to the downstream. While the nitrogen and phosphorus content showed a "fluctuation" growth trend; correlation analysis shows that the concentrations of carbon, nitrogen and phosphorus were significantly related with each other, suggested that the nutrient contents had a synchronous change trend under the development mode of the towns. This study highlights that the bead-like field towns development pattern in mountain river basin would lead an obvious synchronous accumulation of pollutants from the upstream to the downstream, and then beyond the self-purification capacity of river water. In addition, the seasonal variation of carbon, nitrogen and phosphorus concentrations in rivers were mainly affected by runoff dilution, and resulting a pattern of lower concentrations in summer and autumn, and higher in spring. The eutrophication comprehensive index indicates that the monitoring sections of the Heishuitan River were above eutrophication status, and the surface water body has serious nitrogen pollution and light phosphorus pollution. Roughly estimation of the annual input flux of TOC, TN and TP from Heishuitan River to Three Gorges Reservoir amounts to 4057, 1001 and 47 t, which poses a serious threat to the water environment security. The bead-like field town development along the river, forming a specific pollution pattern with "point-surface" dual attributes and threatening the water environment safety of the Three Gorges Reservoir, should be concerned in the future. |
Key words: Field town development Heishuitan River carbon, nitrogen and phosphorus spatial-temporal characteristics eutrophication assessment |
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