ZHU Chunfang，GONG Jianshi，ZHOU Kaie，WANG Heshen，LI Liang，TAO Xiaohu，YE Yonghong

（Nanjing Center，China Geological Survey，Nanjing 210016，China）

Abstract：To study the hydrochemical characteristics and main ion source of shallow groundwater in Fengpei plain area, 27 groups of shallow groundwater samples were collected, and mathematical statistics, Sukalev classification, Gibbs diagram, and the methods of ion scale coefficients were used to reveal the hydrochemical characteristics and forming effect of shallow groundwater in Fengpei plain area. The results show that the cation and anionic is mainly Na+, Ca2+ and HCO- 3, HCO- 3, respectively. The spatial variation coefficient of Mg2+ and Ca2+ is relatively small, while is large for NO- 3. The hydrochemical types in the whole area have obvious horizontal distribution bands according to the different sedimentary environments. In the Huang-Huai-Hai alluvial plain, the hydrochemical types of shallow groundwater transition from HCO3→HCO3-Cl→HCO3-SO4→SO4-HCO3 along the shallow groundwater flow field from southwest to northeast, and the cation transition from Ca-Na-Mg→Na-Mg-Ca→Na-Mg. HCO3-Cl·Ca-Mg-Na is mainly distributed in the alluvial plain of Weishan Lake. Rock weathering, evaporation and crystallization, and ion exchange are the main effects on the formation of shallow groundwater hydrochemical components in this area. In addition, the shallow groundwater in some areas is more affected by industrial and mining activities, less affected by agricultural activities and domestic sewage discharge which showing a point distribution.

Key words：groundwater；Fengpei plain；hydrochemical characteristics；ion source

EARTH AND ENVIRONMENT Vol.50, No.6, Tot No.350, 2022, Page 797