Abstract: The hydrochemical characteristics of groundwater samples collected from Jiaozuo in 2017 were analyzed using mathematical statistics, Piper'plot, and correlation of components. The groundwater quality in the study area were also assessed using the method of single-factor evaluation and fuzzy comprehensive evaluation method based on principal component analysis. Results unveiled that Ca²⁺, Mg²⁺, SO^2-₄ and HCO₃^- were dominant in the groundwater of Jiaozuo. In shallow groundwater, the hydrochemical type evolved from HCO₃-Ca to HCO₃·SO₄-Ca·Mg and HCO₃·SO₄·Cl- Ca·Mg along the direction of groundwater runoff. In deep groundwater, the hydrochemical type was mainly HCO₃·SO₄-Ca·Mg, with some local HCO₃·SO₄-Ca·Mg. The change of ion content in groundwater was mainly affected by weathering and leaching of carbonate, sulfate and rock salt. Single factor evaluation result showed that the excessive TH, Mg²⁺, TDS, SO^2-₄ and other components were major factors that affect the quality of groundwater. Fuzzy comprehensive evaluation results revealed that 61% and 75% of the shallow and deep groundwater quality in the study area met the Ⅲ-level water standard and above. The research findings offer basis for the water quality assessment and reasonable utilization of water resources in Jiaozuo.

Key words: groundwater, hydrochemical characteristics, water quality assessment, principal component analysis, fuzzy comprehensive evaluation, Jiaozuo