Spatial and Temporal Evolution of Groundwater Chemistry of Baotu Karst Water System at Northern China

Autor: Changsuo Li, Xingzhou Zhang, Xubo Gao, Chengcheng Li, Chunfang Jiang, Wen Liu, Guangqi Lin, Xin Zhang, Jiancong Fang, Lijun Ma, Xiubo Zhang
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Minerals, Vol 12, Iss 3, p 348 (2022)
Druh dokumentu: article
ISSN: 2075-163X
DOI: 10.3390/min12030348
Popis: Karst water quality degradation has been a challenge for domestic and industrial water supplies worldwide. To reveal the possible factors response for karst water quality degradation, Baotu karst spring system is studied as an representative example. In this study, a hydrogeochemical investigation and mathematical, statistical, and geochemical modeling was conducted together to identify the major hydrochemical processes involved in the degradation process. It is found that the karst water is normally fresh, neutral-to-slightly alkaline, with calcium and magnesium as the predominant cations, and bicarbonate and sulfate as the predominant anions. The abnormally high chloride (95.05 mg/L) and nitrate concentrations (148.4 mg/L) give clues to the potential source of contamination in some karst water. The main hydrochemical facies of karst water are HCO3-Ca and HCO3 × SO4-Ca, accounting for 76% of water samples. The water hydrochemistry is controlled mainly by the dissolution of carbonate minerals (calcite, dolomite), followed by the dissolution of silicate and gypsum. The dissolution of calcite and dolomite mostly happens in the recharge area. In the discharge area, the karst water is basically in equilibrium with calcite. The negative SI value of gypsum represents that the water–gypsum interaction is dominated by dissolution along the whole flow path. Cation exchange is observed in the karst water in the indirect recharge area. Along the flow path, the contents of chloride, sulfate, nitrate, and TDS (Total dissolved solids, abbreviated TDS, indicates how many milligrams of dissolved solids are dissolved in one liter of water) vary significantly, which is mostly affected by pollution from human industrial and agricultural activities. The concentrations of major ions were maintained at a low level (
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