引用本文：周训,$2,$2,$2,$2,欧业成,黄喜新.2007.浅析广西北海市偏酸性地下水的形成原因[J].地质学报,81(6):850-856. .2007.A Preliminary Analysis of the Formation of the Weak Acidic Groundwater in Beihai, Guangxi[J].Acta Geologica Sinica,81(6):850-856.
1 School of Water Resources and Environment, China University of Geosciences , Beijing, 100083 ; 2 Chinese Academy of Geological Sciences, Beijing , 100037 Beihai Institute of Hydrogeology , Engineering Geology and Mineral Resources in Guangxi , Beihai, G
Abstract:Unconfined and confined aquifers occur in the unconsolidated sediments in the coastal plain near Beihai, Guangxi. Groundwater in the aquifers is of low pH ranging commonly from 4.0 to 6.0. Minerals in unconsolidated Quaternary sediments are predominated by quartz with small amount of clay minerals. SiO2accounts for most of the chemical compositions of the sediments. The sediments containing mainly insoluble constitutes and dissolution of a long time lead to low TDS of the groundwater. Under the natural conditions, H in the groundwater is derivedfrom dissociation of H2CO3, release of the absorbed H2O inclaylayers and the acidity of rainwater. The H2CO3 in the groundwateris formed by dissolutionof CO2. The CO2comes mainly from biologicalcontribution. Lack of alkaline substances in the groundwater system is also helpful in the accumulation of acidity, resulting in a decrease in pH of the groundwater.