| 引用本文: | 任春坪,郑丙辉.高原湖泊水质变化趋势及驱动因素研究:以四川邛海为例.湖泊科学,2024,36(3):756-769. DOI:10.18307/2024.0323 |
| Ren Chunping,Zheng Binghui.Trend recognition and driving factors of water quality change in plateau lakes: A case study of Lake Qionghai, Sichuan Province. J. Lake Sci.2024,36(3):756-769. DOI:10.18307/2024.0323 |
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| 高原湖泊水质变化趋势及驱动因素研究:以四川邛海为例 |
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任春坪1, 郑丙辉2
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1.四川省环境政策研究与规划院,成都 610000;2.中国环境科学研究院,北京 100012
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| 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5 km,生态位置重要。本文以近20年邛海湖区主要水质监测数据为依据,采用M-K检验定量解析了水生态环境历史变化特征,建立邛海污染物浓度、营养状态指标的时空对应关系,分析其驱动因素,识别风险并提出对策建议。结果表明:(1)1980s-2000年是有记录以来邛海水质最差的时期,总氮(TN)、总磷(TP)浓度远超地表水Ⅲ类标准;(2)2003—2020年,邛海氨氮(NH3-N)、高锰酸盐指数(CODMn)年际变化总体呈下降趋势,TN、TP、透明度、溶解氧浓度年际变化趋势总体不明显,CODMn、TN、TP浓度在研究期间出现多个显著变化过程;(3) 2003—2020年,邛海营养状态整体为中营养水平,综合营养状态指数TLI(Σ)为33.82±6.88,叶绿素a(Chl.a)浓度为(4.234±3.903) μg/L,TLI(Σ)和Chl.a浓度年际变化没有显著趋势;(4)多年数据统计表明,邛海宾馆所在区域水质最差,邛海湖心水质最好,2003—2020年CODMn、TP等指标最大单月浓度均出现在邛海宾馆所在水域;(5)CODMn浓度在枯水期低于丰水期,NH3-N浓度在枯水期高于丰水期,TP浓度高值和低值集中出现在枯水期,TN各月浓度没有显著差异,Chl.a浓度与CODMn、TP、NH3-N浓度呈显著正相关,从水体中氮磷比来看,磷是邛海藻类生长限制性元素;(6)面源污染主要通过邛海大小支流入湖,环湖湿地对邛海面源污染削减效果总体有限,未来邛海发生水华的风险较大,建议以小流域为单元推进陆源污染控制,按照“游在邛海,吃、住在城区”的理念布局旅游发展,探索用“物理+生态”方式调控和预防邛海水生态系统失衡的问题。 |
| 关键词: 水质 变化趋势 驱动因素 邛海 |
| DOI：10.18307/2024.0323 |
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| 基金项目:四川省科技重点研发项目(2022YFS0472)和四川省软科学研究计划(2022JDR0350)联合资助。 |
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| Trend recognition and driving factors of water quality change in plateau lakes: A case study of Lake Qionghai, Sichuan Province |
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Ren Chunping1, Zheng Binghui2
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1.Sichuan Academy of Environmental Policy and Planning, Chengdu 610000, P. R. China;2.Chinese Research Academy of Environmental Sciences, Beijing 100012, P. R. China
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| Abstract: |
| Lake Qionghai, the second largest lake in Sichuan, is located <5 km away from Xichang City, with an important ecological meaning. Based on continuous monitoring data over the past 20 years, this work studied the historical changes of the water ecological environment, and established the spatiotemporal correspondence of water quality parameters and nutritional status indicators in Lake Qionghai. The results showed: (1) The water quality was the worst during the period of 1980s-2000, with total nitrogen (TN) and total phosphorus (TP) concentrations far exceeding the Class III standard for surface water. (2) Since 2003, the interannual variation of ammonia nitrogen (NH3-N) and CODMn concentrations in the Lake Qionghai had shown an overall downward trend, while the interannual variation trend of TN, TP, transparency, and dissolved oxygen values was generally insignificant. The concentrations of CODMn, TN, and TP showed a series of significant changes. (3) Since 2003, the trophic status of Lake Qionghai had been at a moderate level, with trophic state index (TLI(Σ)) of 33.82 ±6.88 and chlorophyll-a (Chl.a) concentration of (4.234±3.903) μg/L. There was no significant trend in the interannual variation of TLI(Σ) and Chl.a. (4) The water quality in the area around Qionghai Hotel was the worst, and the water quality in the center of Lake Qionghai was the best. Since 2003, the maximum monthly concentrations of CODMn, TP and other indicators had allappeared in the water area where Qionghai Hotel was located. (5) The concentrations of CODMn in the dry season was significant lower than that in the wet season, and the concentration of NH3-N in the dry season was significant higher than that in the wet season. High and low concentrations of TP occurred during the dry season, and there was no significant difference in monthly concentrations of TN. Chl.a concentration had a significant positive correlation with TP concentration, but there was no significant correlation with TN. Phosphorus was the first controlling factor that restricts algae growth in Lake Qionghai. (6) Pollution from non-point source pollution entered in Lake Qionghai mainly through tributaries. The reduction effect of the wetland around the Lake Qionghai on the non-point source pollution was limited. There would be a high risk of water blooms in the Lake Qionghai in the future. It is recommended to promote the control of land-based pollution in small watersheds, layout tourism development according to the concept of “tourism in the Lake Qionghai, eating and living in Xichang urban areas”, and explore the use of a "physical + ecological" approach to regulate and prevent the imbalance of the Lake Qionghai ecosystem. |
| Key words: Water quality change trends driving factors Lake Qionghai |
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