Hydrogeochemistry of Shallow Groundwater in a Karst Aquifer System of Bijie City, Guizhou Province

• Published in: Water (Basel) Vol. 9; no. 8; p. 625
• Main Authors: Yuan, Jianfei, Xu, Fen, Deng, Guoshi, Tang, Yeqi, Li, Pengyue
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.08.2017
• Subjects: Anthropogenic factors; Aquifer systems; Aquifers; Calcite; Calcium; Carbonates; Cation exchange; Cation exchanging; Coal mines; Coal mining; Dissolution; Dolomite; Geochemistry; Groundwater; Gypsum; Halites; Human influences; Hydrogeochemistry; Karst; karst aquifer; Magnesium; major ions; Minerals; PCA; Principal components analysis; Rain-water (Water-supply); Rock-salt; Saturation; Saturation index; water isotopes; Water, Underground; China
• ISSN: 2073-4441; 2073-4441
• DOI: 10.3390/w9080625

In this study, the major chemical compositions of 159 shallow groundwater samples incorporated saturation index (SI) and Principal Component Analysis (PCA) were employed to evaluate the mainly geochemical processes that control the hydrogeochemical evolution of groundwater in a typical karst area, Bijie city, Guizhou Province. The groundwater samples in this study area were dominated of HCO[sub.3]-Ca, HCO[sub.3]-Ca-Mg, and HCO[sub.3]-SO[sub.4]-Ca types. The PCA suggested that four principal components could explain 88.85% of the total variance of 10 parameters, indicating that the hydrogeochemical evolution of groundwater was mainly controlled by the dissolution/precipitation of carbonates, gypsum, and halite minerals, cation exchange, and anthropogenic activities. To be specific, the enrichment of Ca[sup.2+], Mg[sup.2+], HCO[sub.3] [sup.−] and SO[sub.4] [sup.2−] in groundwater were primarily affected by the dissolution of dolomite and gypsum minerals, and the role of calcite dissolution was relatively weaker because most groundwater samples were saturated with respect to calcite. Besides, cation exchange was another factor that may affect the concentration of Ca[sup.2+] and Mg[sup.2+] in groundwater, and the concentration of SO[sub.4] [sup.2−] can also be influenced by coal mining activity. In addition, the concentrations of Na[sup.+] and Cl[sup.−] in groundwater were likely influenced by the dissolution of halite, cation exchange, and human activities.