山西长治辛安泉域岩溶水硫酸盐污染来源分析

Analysis of Sulfate Pollution Sources in Karst Water of Xin'an Spring Area in Changzhi, Shanxi Province

辛安泉域核心区域工农业相对发达,人类活动强烈,逐渐出现岩溶地下水位下降、泉流量减小和水质污染等水环境问题。硫酸盐污染是泉域岩溶水的主要污染物之一,通过科学手段进行污染来源分析和识别,可为泉域保护提供决策依据。硫氧同位素是地下水领域应用较广的一种环境同位素方法,不仅技术成熟且识别精度高。本次研究将硫氧同位素方法与水化学方法结合,在辛安泉域采取岩溶泉水、岩溶地下水、孔隙水、裂隙水和河水五类水样,测试硫同位素δ^(34)S、氧同位素δ^(18)O和硫酸根离子SO_(4)^(2-)含量,以分析辛安泉域岩溶水硫酸盐污染来源。结果显示,辛安泉域岩溶水水质的硫酸盐大部分符合地下水III类标准,硫酸盐含量较高的区域主要集中在西部滞流缓流区与襄垣和长治子系统的分界处、长治子系统和平顺-壶关子系统南部等地区。西部滞流缓流区硫酸盐主要来源于石膏、硬石膏的溶蚀,人类活动影响较小。泉域南部岩溶水中硫酸盐主要来源是煤矿开采的影响,大气沉降也是重要来源之一。

The core area of Xin'an spring area is relatively developed in industry and agriculture,with strong human activities,gradually leading to water environment problems such as decreased karst groundwater level,reduced spring flow,and water pollution.Sulfate pollution is one of the main pollutants in karst water in spring areas.Analyzing and identifying pollution sources through scientific means can provide decision-making basis for spring protection.Sulfur and oxygen isotopes are widely used environmental isotope methods in the field of groundwater,with mature technology and high identification accuracy.This study combines sulfur and oxygen isotope methods with hydrochemical methods to test sulfur isotopes in five types of water samples:karst spring water,karst groundwater,pore water,fissure water,and river water in the Xin'an spring domainδ^(34)S,oxygen isotopesδ^(18)O and sulfate ion SO_(4)^(2-)content to analyze the source of sulfate pollution in karst water of Xin'an spring area.The results show that most of the sulfate content in the karst water quality of Xin'an spring area meets the Class III groundwater standard.The areas with high sulfate content are mainly concentrated at the boundary between the western stagnant flow area and the Xiangyuan and Changzhi subsystems,as well as in the southern part of the Changzhi subsystem and the Pingshun Huguan subsystem.The sulfate in the western stagnant slow flow zone mainly comes from the dissolution of gypsum and anhydrite,and the impact of human activities is relatively small.The main source of sulfate in the karst water in the southern part of the spring region is the impact of coal mining,and atmospheric sedimentation is also an important source.