Abstract:  Groundwater is the main source of production and living water for local rural residents in Chaoshan area，Guangdong Province. However, as a prominent groundwater environmental problem in recent years, the acidic shallow groundwater has had different degrees of impact on the health of residents and the balance of ecological environment. In this study, the groundwater drinking water source area in Fenghuang Town, Chao’an district was taken as the study area. The spatial and temporal distribution characteristics, hydrochemical types, characteristics and formation mechanism of pH value of acidic shallow groundwater in groundwater drinking water source area were analyzed by means of mathematical statistics and hydrochemistry. The results show that the groundwater in the study area has the characteristics of weak acidity and low total dissoloved solid （TDS）, and the hydrochemical types are mainly HCO3-Na type and HCO3-Na·Ca type. The rainfall in the study area is acidic as a whole, and there is no obvious pollution source related to pH change in the surrounding area. pH value is obviously affected by water-rock interaction and cation exchange. The weathering of silicate minerals and the dissolution of CO2 are the main sources of HCO3-. The dissolution and leaching of granite is the main source of H+. In summary, the acid shallow groundwater in the study area is mainly affected by acid rain leaching, leaching in aquifer media and cation exchange. In this study, through the analysis of the distribution characteristics and formation factors of acidic groundwater in the groundwater drinking water source area of Chaoshan area, it is of great significance to the rational utilization and development of shallow groundwater and the protection of groundwater resources.

Key words: groundwater drinking water source, acid groundwater, hydrochemistry, influencing factor, Chaoshan area, Guangdong Province