Water chemical formation mechanism and water quality analysis of Shichuan River under the influence of human activities

ABSTRACT

It is necessary to analyze the characteristics of the water environment and factors influencing the basin in order to determine its current ecological status. This study aims to investigate the chemical properties in the Shichuan River Basin using Gibbs diagram, Piper triangle diagram, correlation analysis, factor analysis, and main ion ratio method. The enhanced Nemerow comprehensive index method and fuzzy comprehensive evaluation method are employed for river water quality assessment. The findings reveal that runoff water has a weak alkaline nature with low salinity. The hydrochemical type of river water includes Ca²⁺+Mg²⁺+Na⁺-SO₄^2-, Ca²⁺+Mg²⁺-SO₄^2-+Cl^-+HCO₃^-, Ca²⁺+Na⁺-SO₄^2-+Cl^-+HCO₃^-. Silicite and dolomite weathering are identified as primary influencing factors, while evaporite weathering also contributes to variations in chemical composition within the basin's waters. Ca²⁺, Mg²⁺, SO₄^2- and HCO₃^- originate from carbonate rock and silicate rock weathering processes, whereas Na⁺, K⁺ and Cl^-, are primarily derived from evaporite weathering influenced by domestic sewage and agricultural activities. Agricultural production practices along with discharge of domestic sewage have an impact on Na⁺, K⁺, Cl^- and NO₃^-concentrations in aquatic systems. Water quality at all three monitoring sections falls under level IV classification. Phosphorus emerges as a key limiting factor for eutrophication within this basin's watersheds.

KEYWORDS:

• Hydrochemical mechanism;water quality
• comprehensive assessment
• surface water
• Shichuan River Basin

Acknowledgments

The authors are very grateful for engineer Zhao Yu and Han Chen of Key Laboratory for Ecology and Environment of River Wetlands in Shaanxi Province because of their help in sample test. This work is supported by the National Natural Science Foundation of China (41901012), Project of Shaanxi Provincial Education Department (21JP040), Talent Fund Project of Weinan Normal University (2021RC04).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Natural Science Foundation of China [grant number: 41901012]; National Innovation and Entrepreneurship Training Program for College Students [grant number: 22XK019]; Project of Shaanxi Provincial Education Department [grant number: 21JP040].

Notes on contributors

Xiaoyan Wang

Xiaoyan Wang, female, PHD, associate professor, mainly engaged in basin hydrology and water resources research.

Canwen Jiang

Canwen Jiang, male, PHD, associate professor, mainly engaged in environmental chemistry.