江汉平原东部地区浅层地下水水化学特征
Hydrochemical Characteristics of Shallow Groundwater in Eastern Jianghan Plain

浅层地下水是江汉平原东部地区重要的供水水源，但面临着污染及天然水质异常等问题.基于水化学与氢氧同位素结果，并运用数理统计和因子分析等方法，查明了研究区浅层地下水的化学特征、控制过程以及影响因素.结果显示，浅层地下水的化学类型主要为HCO3-Ca型；其中潜水中Ca2+和Mg2+含量与承压水接近，Fe、As和NH4+含量低于承压水，而Cl-、SO42-、Mn和NO3-含量高于承压水.浅层地下水主要为大气降水补给，其中潜水经历了一定程度的蒸发以及与地表水的混合.在影响浅层地下水化学特征的因素中，地质成因在总体上可能起主导作用；人类活动的输入显著地改变着潜水的化学特征，而浅层承压水则主要受径流过程中水-岩相互作用的影响.
The shallow groundwater is an important water supply source in the eastern Jianghan plain, but it is confronted with pollution and inferior quality of natural water. This study identifies the chemical characteristics, control processes and influencing factors of shallow groundwater in the study area based on the results of water chemistry, hydrogen and oxygen isotope, using methods of mathematical statistics and factor analysis. Results show that the shallow groundwater chemical types are mainly HCO3-Ca, the contents of Ca2+ and Mg2+ in the phreatic water are close to those in confined water, the contents of the As, Fe, NH4+ are lower than those in confined water, but the contents of the Cl- , SO42-, Mn and NO3- are higher than those in confined water. The shallow groundwater mainly originates from precipitation and the phreatic water has experienced a degree of evaporation and the mixture of surface water. Among the influencing factors of shallow groundwater chemical characteristics, the geologic origin may play a leading role; human activities have dramatically changed the chemical characteristics of the phreatic water, and the shallow confined water is mainly affected by water-rock interaction of the runoff process