典型农业活动区浅层地下水地球化学特征及成因分析

Shallow Groundwater Geochemical Characteristics and Formation in Typical Agricultural Activity Area

以常州市为研究区域,采用现场调查和实验室分析相结合的方法,对常州市浅层地下水HCO3-、Cl-、SO42-、F-、Na+、K+等10种指标进行检测,并分析浅层地下水的水质状况、地球化学特征和成因机理。在常州市浅层地下水样中,第四系松散岩类孔隙潜水有2个水样总硬度超标,微承压水和第Ⅰ承压水各有1个水样总硬度超标。常州市浅层地下水化学类型主要为HCO3-Ca.Na(Na.Ca)和HCO3-Ca.Mg,在常州的东南和西部少部分地区出现几种类型的地下水。这与常州全区地势平坦、地下水径流微弱具有一致性。常州市孔隙潜水、微承压水和第Ⅰ承压水中,各种离子存在一定的分布规律,且在各含水层的分布规律不同。常州市浅层地下水化学特征主要与地下水离子间的交换吸附作用、人类生产生活活动和浅层地下水的酸碱性有关。

Ten indexes of shallow groundwater in Changzhou including HCO3-,Cl-,SO42-,F-,Na＋,K＋,were detected with field survey and laboratory analysis,and the quality,geochemical trait and formation mechanism of shallow groundwater were analyzed.The total hardness of 2 samples of the poor phreatic water in loosening rocks of quaternary period,1 sample of micro confined water,1 sample of the first confined water exceed the standard.The main chemical types of shallow groundwater in Changzhou are HCO3-Ca·Na（Na·Ca） and HCO3-Ca·Mg.There are different chemical types of shallow groundwater in the several areas of the southeast and west of Changzhou,which coincide with the flat topography and weak runoff of groundwater.There is a certain distribution regularity of various ions in the poor phreatic water,micro confined water and the first confined,and the distribution regularities in different aquifers are different.The chemical types of shallow groundwater are mainly correlated with the exchange adsorption effect of ions,the activities of human production and life and acid-base of shallow ground water.