[Major Ionic Features and Possible Controls in the Groundwater in the Hamatong River Basin].

In order to study the major ion chemistry and controls of groundwater, 59 groundwater samples were collected and their major ions measured in the Hamatong River Basin. The hydrogeochemical characteristics of groundwater in this basin were analyzed by means of mathematical statistics, Piper triangular diagrams, Gibbs figures, and ionic relations, and the water chemical evolution and ion sources of the Hamatong River Basin were determined. The results showed that Ca2+ was the main cation in the groundwater, accounting for 22.1% to 72.4% of the total cations, with an average value of 48.7%. HCO3- was the main anion, accounting for 35.3% to 97.5% of the total anions, and with an average value of 80%. Total dissolved solids concentration ranged from 93.3 mg·L-1 to 521.1 mg·L-1 with a median value of 219.1 mg·L-1. The hydrochemical types of groundwater are HCO3-Ca, HCO3-Ca·Mg, and HCO3-Ca·Na. Chemical weathering rates of carbonates and silicates were estimated, and the chemical composition of groundwater samples located in the middle of Gibbs model indicated that the major chemical process of groundwater was controlled by rock weathering. Silicate weathering is believed to significantly contribute to dissolved solute compositions, and carbonate weathering played an important role as the source of dissolved ions.

[Hydrochemical Characteristics of Groundwater and the Origin in Alluvial-proluvial Fan of Qinhe River].

To study the hydrochemical characteristics of groundwater and the factors controlling the alluvial-proluvial fan of the Qinhe River, 60 samples were collected including 9 surface water samples and 51 groundwater samples. The distribution characteristics of the hydrochemistry and major controlling factors of hydrochemical evolution processes of surface water and groundwater in the study area were analyzed by using mathematical statistics, the Schakerev classification, Piper diagrams, Schoeller diagrams, Gibbs plots, and ion ratios. The results show that:① the major anions and cations of surface water and groundwater in the study area are Ca2+, Mg2+, SO42-, and HCO3-. The recharge sources of surface water and groundwater are closely related; ② the major hydrochemical types of the groundwater are HCO3-Ca, HCO3-Ca·Mg, and HCO3·SO4-Ca·Mg, while the major hydrochemical type of surface water is HCO3·SO4-Ca·Mg; and ③ the major ions of surface water and groundwater are affected by carbonate mineral weathering and dissolution, ion exchange, and evaporation. Sulfuric acid and carbonic acid were involved in carbonate mineral weathering and dissolution.

[Major Ionic Features and Their Possible Controls in the Water of the Niyang River Basin].

In order to study the hydrochemical characteristics and their possible controls for the chemical composition of the water from the Niyang River Basin, 30 samples were collected from wells, springs, and the river in 2014 and major ion concentrations were measured. Descriptive statistics, the Gibbs figure, an ion ratio, and Piper triangular diagrams were used to investigate the hydrochemical characteristics, influencing factors, and hydrochemical evolution of the water in the basin. The results showed that the major cations in this water were Ca2+ and Mg2+, accounting for more than 84% of cations and the main anions were HCO3- and SO42-, accounting for more than 97% of anions The hydrochemical typology of the water is HCO3·SO4(SO4·HCO3)-Ca·Mg (Mg·Ca). The total dissolved solids (TDS) in the water ranges from 79.11 to 290.48 mg·L-1 with an average of 165.21 mg·L-1. The chemical composition of water samples is located to the left of the Gibbs model, which indicates that the chemical process of Niyang River Basin are controlled by rock weathering. According to the principal component analysis and correlation analysis, the hydrochemical composition is controlled by silicate weathering, however, carbonate weathering also plays an important role.