豫北平原浅层地下水化学特征与成因机制

地下水的化学特征与成因机制对地下水演化、地下水资源的合理开采及质量评价具有重要意义。为查明豫北平原浅层地下水的水质特征及控制因素，采集了不同类型的浅层地下水和地表水样品，分别测试了水样阴、阳离子和氢氧同位素组成。结果表明:①地下水中总溶解性固体物质（total dissolved solids，简称TDS）质量浓度范围为316~6 948 mg/L，微咸和咸地下水呈条带状分布在沁河冲洪积平原中部，在三阳镇-修武县一带，水化学类型复杂，以HCO₃·SO₄-Na·Mg·Ca型和SO₄-Na·Mg型水为主。北部山前冲洪积扇和沁河北岸地下水为淡水，为HCO₃-Ca·Mg型水。②δ2H-δ18O关系说明地下水起源于大气降水，水化学组分受水岩相互作用控制，在补给区以碳酸盐岩溶滤作用为主，径流区发生硅酸盐岩的风化溶解以及阳离子交换作用，排泄区以蒸发浓缩、石膏溶解和阳离子交换作用为主。③地质和气候环境是造成地下水咸化的主要成因，且受到工农业污水渗漏的影响。研究成果可以为该区地下水资源的合理开采和有效管理提供依据。 

Chemical characteristics and formation mechanism of shallow groundwater in the northern Henan Plain

The chemical components and formation mechanism are of great significance for groundwater evolution, reasonable exploitation, and the quality evaluation of water resources.To clarify the water quality characteristics and its control factors of shallow groundwater in the northern Henan Plain, different types of water samples were collected, and the anion, cation and hydrogen and oxygen isotopic compositions of the water samples were tested, respectively.The results show that: ① The range of groundwater TDS is 316-6 948 mg/L, and the brackish and saline groundwater are in the center of alluvial and diluvial plain of Qinhe river, along the area of Sanyang Town to Xiuwu County, with the major water types of HCO₃·SO₄·Cl-Na·Mg and SO₄-Na·Mg.In the northern alluvial fan landform and the north shore of Qinhe River, groundwater is freshen with the water type of HCO₃-Ca·Mg.② The hydrogen and oxygen isotopic composition of groundwater indicates that groundwater originates from atmospheric precipitation and the evolution of chemical components are dominated by water-rock interactions.The groundwater is controlled by carbonate leaching in the recharge area, the weathering of silicate and cation exchange occur in the runoff area, and the drainage area is dominated by evaporation, gypsum dissolution and concentration and cation exchange.To a certain extent, it is also affected by human activities.③ The geological condition and climate are the main cause of the formation of saline groundwater, and also it is affected by leakage of industrial and agricultural sewage.The results can provide a basis for the rational exploitation and offective management of groundwater resources in this area.