[Hydrochemical and Isotopic Evidence for Groundwater Conversion of Surface Water in Alpine Arid Areas: A Case Study of the Datong River Basin].

Global warming and regional extreme climates will lead to unbalanced rainfall, melting glaciers, and permafrost degradation in alpine and arid mountain plains, thereby changing the regional hydrological cycle. The relationship between surface water and groundwater conversion is one of the important scientific issues of hydrological cycle climate response in alpine arid areas. Taking the Datong River Basin at the southern foot of the Qilian Mountains as the study area, based on 119 sets of basic hydrochemical parameters and deuterium-oxygen isotope data, using multivariate statistical analysis and isotopic techniques, the hydrochemical characteristics of surface water and groundwater in the basin and their mutual transformation process were studied.

Origins of groundwater nitrate in a typical alluvial-pluvial plain of North China plain: New insights from groundwater age-dating and isotopic fingerprinting.

Identifying nitrate sources and their temporal evolution in different land use is important for the sustainable management of groundwater resources. In this study, groundwater dating (H-He and time series of H) was combined with chemical and stable isotope analyses to resolve the evolution of nitrate sources and the driving mechanism of nitrate contamination. Approximately 75% of the groundwater samples (collected in 2014 and 2018) had nitrate concentrations exceeding World Health Organization's guideline for drinking water (50 mg/L), and 44% exceeded the groundwater quality standard of China (88.

Quantitative identification of groundwater contamination sources by combining isotope tracer technique with PMF model in an arid area of northwestern China.

Nowadays, groundwater quality has deteriorated because of intensive human activities. It is important to accurately identify the pollution source for controlling the deterioration of groundwater quality. However, the accuracy of the current source analysis method needs to be improved.

Distributions, origins, and health-risk assessment of nitrate in groundwater in typical alluvial-pluvial fans, North China Plain.

High concentration of nitrate (NO) in groundwater is a major concern because of its complex origin and harmful effects on human health. This study aims to investigate the distributions of nitrate in various aquifers and in areas with different land use types in alluvial-pluvial fans in North China Plain, to identify dominant sources and factors using hydrochemical data and principal component analysis, and to conduct health-risk assessment of groundwater nitrate using the models recommended by USEPA. Results show that approximately 76.

Groundwater quality assessment and pollution source apportionment in an intensely exploited region of northern China.

Deterioration in groundwater quality has attracted wide social interest in China. In this study, groundwater quality was monitored during December 2014 at 115 sites in the Hutuo River alluvial-pluvial fan region of northern China. Results showed that 21.