| 摘要: |
| 邛海是四川第二大湖泊,地处高原,距离西昌市城区不足5km,生态位置重要.以近20年连续监测数据为依据, 研究水生态环境历史变化特征研究,建立邛海污染物浓度、富营养化指标与时间空间对应关系,分析驱动因素, 识别风险并提出对策建议.结果表明:(1)上世纪80年代-2000年是有记录以来邛海水质最差的时期, TN、TP浓度远超地表水Ⅲ类标准；(2)年际变化来看,2003年以来邛海NH3-N浓度持续下降, CODMn、TN、TP浓度出现“恶化-改善-恶化-再改善”的过程;(3)空间分析表明邛海宾馆所在区域水质显著劣于邛海湖心, CODMn、TP等指标单月最大浓度主要出现在邛海宾馆所在水域;(4)邛海TLI值、Chl.a浓度年际均没有显著变化趋势,两者存显著正相关,TLI值能较好表征富营养状况,Chl.a浓度与TP浓度存显著正相关,与TN相关性不显著,磷是邛海藻类生长首要限制性元素; (5)????????????? CODMn浓度枯水期显著低于丰水期,NH3-N浓度枯水期显著高于丰水期,TP浓度高值和低质集中出现在枯水期, TN各月浓度没有显著差异,CODMn浓度主要受面源影响,NH3-N浓度主要受点源影响,TN、TP浓度受点、面源复合影响;(6)邛海面源污染主要通过大小支流入湖,环湖湿地对其中源污染削减效果总体有限,未来邛海发生水华的风险较大,建议优化邛海流域空间管控,深入推进陆源污染控制,试点推进农业面源 “源头减量-资源利用-末端治理”的全链条污染综合防治. |
| 关键词: 水质 变化趋势 驱动因素 邛海 |
| DOI： |
| 分类号: |
| 基金项目:四川省科技重点研发项目(NO.2022YFS0472). 四川省软科学研究计划( NO.2022JDR0350). |
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| Trend Recognition and Driving Factors Study of Water Quality Change in urban plateau |
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Ren Chunping1, Zheng binghui2
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1.Sichuan Academy of Environmental Policy and Planning;2.Chinese Research Academy of Environmental Sciences
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| Abstract: |
| Qionghai Lake, the second largest lake in Sichuan, is located less than 5km away from Xichang City, with an important ecological position. Based on continuous monitoring data from the past 20 years, study the historical changes of the water ecological environment, establish the corresponding relationship between pollutant concentration, eutrophication indicators, and time and space in Qionghai Lake, analyze driving factors, identify risks, and propose countermeasures and suggestions. The result showed as follow : (1)The period from the 1980s to 2000 was the worst recorded period for water quality in the Qionghai Sea, with TN and TP concentrations far exceeding the Class III standard for surface water.(2) Since 2003, the NH3-N concentration in the Qionghai Lake has been continuously decreasing, and the concentrations of CODMn, TN, and TP have undergone a "deterioration- improvement deterioration- improvement" process. (3)The water quality in the area where Qionghai Hotel is located was significantly worse than that in the center of Qionghai Lake, and the maximum concentration of CODMn, TP and other indicators in a single month mainly occured in the water area where Qionghai Hotel is located.(4) Since 2013, there has been no significant trend in the TLI value and Chl. a concentration in the Qionghai Lake, which have a significant positive correlation. The TLI can better characterize eutrophication status in Qionghai Lake. Chl. a concentration had a significant positive correlation with TP concentration, but there was no significant correlation with TN. Phosphorus was the first controlling element that restricts algae growth in Qionghai Lake. (5) The concentration of CODMn in the dry season was significantly lower than that in the wet season, and the concentration of NH3-N in the dry season was significantly higher than that in the wet season. High and low concentrations of TP occur during the dry season, and there is no significant difference in monthly concentration of TN. The concentration of CODMn was mainly influenced by nonpoint sources (NPSs) pollution, while the concentration of NH3-N was mainly influenced by point sources. The concentration of TN and TP is influenced by the combination of point and NPSs pollution. (6) Pollution from NPSs entered in Qionghai Lake mainly through tributaries. The reduction effect of the wetland around the lake on the NPSs pollution was limited, and the risk of water bloom in the Qionghai Lake in the future is high. It is recommended to optimize the spatial control of the Qionghai Basin, deepen the control of land-based pollution, and pilot the comprehensive prevention and control of agricultural NPSs pollution through the entire chain of "source reduction resource utilization end treatment |
| Key words: water quality change trends driving factors Qionghai Lake |
