State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; Kunming Institute of Eco-Environmental Sciences, Kunming, 650032, China.
Kunming Institute of Eco-Environmental Sciences, Kunming, 650032, China.
Environ Pollut. 2022 Nov 1;312:119992. doi: 10.1016/j.envpol.2022.119992. Epub 2022 Aug 24.
Eutrophication is an important water environment issue facing global lakes. Diversion of water from external watersheds into lakes is considered as effective in ameliorating eutrophication and reducing algal blooms. Nevertheless, the changes in lake water environment caused by external water diversion, especially the influence of water diversion on the characteristics of dissolved organic matters (DOM), are still poorly understood. We therefore used a combination of EEM-PARAFAC, Principal Component Analysis (PCA), and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) to investigate the effects of water diversion from the Niulan River on DOM characteristics in Lake Dianchi. The results showed that the water diversion from the Niulan River significantly improved the water quality of Lake Dianchi, the concentrations of TN, TP, COD and Chla decreased rapidly, and the degree of humification of dissolved organic matter (DOM) increased, which was in sharp contrast with that of pre-implementation. Firstly, the diversion of water from the Niulan River mainly led to changes in the structure of pollution sources. The load of influent rivers and sewage treatment plants rich in lignin and tannins increased, and the input of terrestrial humus increased. Second, the improved water quality reduced algal enrichment and frequency of blooms, and reduced the release of lipid- and protein-riched algal-derived DOM. Finally, the hydraulic retention time of Lake Dianchi caused by water diversion was shortened, the hydrodynamic conditions were significantly improved, and the dissolved oxygen (DO) level gradually recovered, which played a positive role in improving the humification degree of DOM. Our findings provide new insights for exploring the improvement of eutrophic lake eco-environmental quality caused by water diversion projects.
富营养化是全球湖泊面临的一个重要水环境问题。从外部流域引水入湖被认为是改善富营养化和减少藻类水华的有效方法。然而，外部引水对湖泊水环境的变化，特别是对溶解有机物（DOM）特征的影响，仍了解甚少。因此，我们采用三维荧光光谱结合平行因子分析（EEM-PARAFAC）、主成分分析（PCA）和傅里叶变换离子回旋共振质谱（FT-ICR-MS）的方法，研究了牛栏江引水对滇池 DOM 特征的影响。结果表明，牛栏江引水显著改善了滇池水质，TN、TP、COD 和 Chla 浓度迅速下降，DOM 的腐殖化程度增加，与实施前形成鲜明对比。首先，牛栏江引水主要导致污染源结构发生变化。富含有机物的河流和污水处理厂的负荷增加，输入的陆地腐殖质增加。其次，水质的改善减少了藻类富营养化和水华的发生频率，减少了富含脂质和蛋白质的藻类衍生 DOM 的释放。最后，引水导致滇池水力停留时间缩短，水动力条件明显改善，溶解氧（DO）水平逐渐恢复，这对提高 DOM 的腐殖化程度起到了积极作用。我们的研究结果为探索引水工程改善富营养化湖泊生态环境质量提供了新的见解。
