[Research Advances of Groundwater Nitrate Pollution and Source Apportionment in China].

Groundwater nitrate (NO) contamination in China has become a serious environmental problem, especially in agricultural production areas, which greatly affects the safety of drinking groundwater and requires urgent attention. In this study, the main sources of groundwater nitrate in China were reviewed, including atmospheric deposition, soil nitrogen, agricultural fertilization, and fecal sewage, among which fecal sewage and agricultural fertilization were the main reasons for the excessive groundwater nitrate. The application of hydrochemical analysis, multivariate statistical analysis, stable isotope tracer method, and microbial source tracking in the source apportionment of groundwater nitrate was summarized.

[Hydrochemical Characteristics and Control Factors of Surface Water in Kuaize River Basin at the Upper Pearl River].

The Kuaize River is a small typical karst watershed in the source area of the Pearl River as well as an important coal mining area in Eastern Yunnan with a fragile ecological environment. Strengthening the research on the water environment in the region plays an important role in supporting the comprehensive management of the ecological environment and water resources in the source region of the Pearl River. Through the systematic collection of surface water, karst groundwater, and mine water samples, mathematical statistics analysis, correlation analysis, ion ratio analysis, absolute principal component scores multiple linear regression(APCS-MLR), and other methods were used to study the characteristics of hydrochemical evolution and control factors in Kuaize River Basin.

[Hydrochemical Composition Characteristics and Control Factors of Xiaohuangni River Basin in the Upper Pearl River].

In order to serve the water resources management of the Xiaohuangni River basin, this study explored the hydrochemical composition characteristics and ion sources of surface water in the basin. Samples of main stream and tributary river water and mine water were systematically collected. By means of a Piper diagram, Gibbs diagram, ion ratio coefficient, and mathematical statistical analysis, we analyzed the hydrochemical composition, spatial distribution characteristics, and main control factors of the Xiaohuangni River and evaluated the solute contribution rates of different sources.