基于水化学与硫同位素的卡林型金矿区岩溶水文地球化学特征及控制因素  

Karst Hydrogeochemical Characteristics and Controlling Factors of Carlin-type Gold Mining Area Based on Hydrochemistry and Sulfur Isotope

作　　者：查学芳[1,2] 吴攀[1,2] 李学先 陈世万 黄家琰[2] 李清光 陈思睿 ZHA Xue-fang;WU Pan;LI Xue-xian;CHEN Shi-wan;HUANG Jia-yan;LI Qing-gang;CHEN Si-rui(Key Laboratory of Karst Georesources and Environment,Ministry of Education,Guizhou University,Guiyang 550025,China;Guizhou Karst Environmental Ecosystems Observation and Research Station,Ministry of Education,College of Resources and Environmental Engineering,Guizhou University,Guiyang 550025,China;College of Agriculture,Guizhou University,Guiyang 550025,China)

机构地区：[1]贵州大学喀斯特地质资源与环境教育部重点实验室,贵阳550025 [2]贵州大学资源与环境工程学院,贵州喀斯特环境生态系统教育部野外科学观测研究站,贵阳550025 [3]贵州大学农学院,贵阳550025

出　　处：《环境科学》2022年第11期5084-5095,共12页Environmental Science

基　　金：国家重点研发计划项目(2019YFC1805300);贵州省科技计划项目(黔科合基础-ZK[2021]一般234)。

摘　　要：采矿活动通过抽排改变地下水水位和流动条件,促进了地下水与含水层岩石之间的相互作用,同时矿山排水排入地表水系,从而影响整个岩溶水系统的水文地球化学过程.基于水文地球化学和δ^(34) S同位素,揭示了典型卡林型金矿区及其周边矿山废水、岩溶地下水、地表水等水文地球化学过程、特征及其主要控制因子.结果表明,未受金矿开采活动影响的地下水和地表水的丰、枯水期水化学组分主要受灰岩和白云质灰岩风化作用控制,离子以Ca^(2+)、Mg^(2+)和HCO_(3)^(-)为主,水化学类型均为Ca-HCO_(3)型.而矿山废水及其下游受纳水体受碳酸盐和硅酸盐矿物溶蚀与离子交换作用影响,离子以Ca^(2+)、Mg^(2+)、Na^(+)和SO_(4)^(2-)为主,水化学类型由Ca-HCO_(3)型逐步演化为Ca-SO_(4)型.受矿山开采影响的各类水体中SO_(4)^(2-)是特征组分,SO_(4)^(2-)浓度在井下呈现从上至下逐渐降低的显著规律.未受矿山废水影响的地下水和地表水δ^(34) S值偏正,SO_(4)^(2-)主要来源于雄黄矿的氧化,而矿山废水及其下游受纳水体δ^(34) S值偏负,SO_(4)^(2-)主要受雄黄矿氧化和大气降水两个端元混合作用的影响,黄铁矿也有一定贡献.同时,各类水体的NO_(3)^(-)源于农业化肥施用和农村生活污水直排的输入.Mining activities change the groundwater level and flow conditions through pumping and drainage, which enhances the interaction between groundwater and aquifer rocks;mine drainage is discharged into the surface water system, which affects the whole karst water hydrogeochemical process. Based on hydrogeochemistry and the δ^(34)S isotope, the hydrogeochemical processes, characteristics, and main controlling factors for waste water, karst groundwater, and surface water in a typical Carlin gold mining area and its surrounding areas were revealed. The results showed that:chemical compositions of groundwater and surface water unaffected by gold mining activities were mainly controlled by the weathering of limestone and dolomitic limestone;Ca^(2+), Mg^(2+), and HCO_(3)^(-) were main ions;and the water chemical types were Ca-HCO_(3). The mine wastewater and its downstream receiving water were affected by the dissolution of carbonate and silicate minerals, and cation exchange also played a role;the main ions were Ca^(2+), Mg^(2+), Na^(+), and SO_(4)^(2-), and the hydrochemical type gradually evolved from Ca-HCO_(3) to Ca-SO_(4). SO_(4)^(2-) was the characteristic component in various water bodies affected by mining, and the concentration of SO_(4)^(2-) gradually decreased from top to bottom in the well. The values of δ^(34)S for unaffected groundwater and surface water were positive, and SO_(4)^(2-) was mainly derived from realgar oxidation. Conversely, mine wastewater and downstream water were negative, SO_(4)^(2-) was mainly influenced by the mixing action of realgar oxidation and meteoric precipitation, and pyrite also contributed to a certain extent. At the same time, NO_(3)^(-) came from agricultural fertilizer and rural domestic sewage discharge directly. Principal component analysis (PCA) further demonstrated:sulfide mineral oxidation and mining activities were the main controlling factors for the water chemical composition of mine wastewater and downstream water, whereas unaffected groundwater and surface water

关 键 词：水文地球化学 硫同位素 离子来源 控制因素 主成分分析(PCA) 卡林型金矿区 

分 类 号：X523[环境科学与工程—环境工程]