大冶铁矿区地下水水化学演化过程及铁和硫酸盐污染机制  

Hydrochemical Evolution Processes and Mechanism of Groundwater Iron and Sulfate Pollution in Daye Mining Area

作　　者：李伟 耿函 苏春利 曹慧丽 梁川 卫方成 LI Wei;GENG Han;SU Chunli;CAO Huili;LIANG Chuan;WEI Fangcheng(Geological Environmental Center of Hubei Province,Wuhan 430034,China;School of EnvironmentaI Studies,China University of Geosciences(Wuhan),Wuhan 430078,China)

机构地区：[1]湖北省地质环境总站,湖北武汉430034 [2]中国地质大学(武汉)环境学院,湖北武汉430078

出　　处：《安全与环境工程》2023年第2期223-232,共10页Safety and Environmental Engineering

基　　金：国家自然科学基金项目(42177078)。

摘　　要：大冶铁矿区由于长期采矿活动,生态环境、地下水环境均衡受到严重的影响,并伴生地下水污染。通过地下水水化学特征和同位素分析,查明了大冶铁矿区地下水污染物分布特征,并通过反向地球化学模拟,探讨了地下水径流过程中区域地下水主要水文地球化学演化过程以及特征污染物的迁移过程和污染机理。结果表明:大冶铁矿区地下水赋存于弱碱性氧化环境,地下水水化学类型主要为HCO_(3)·SO_(4)-Ca型水;碳酸盐岩和硅酸盐水解是研究区地下水水化学组分的主要来源,且受到不同程度蒸发盐岩溶解、矿坑排水和人类生活污染的影响;区域地下水中Fe和SO_(4)^(2-)浓度高值区主要分布在洪山溪尾矿库、矿渣堆存处附近,上邹国控点DYTKQ04泉水中硫酸盐浓度超标(>250mg/L),而Fe浓度较低;沿地下水流动路径方向,主要发生了脱白云石化、离子交换作用和黄铁矿的氧化作用,地下水中SO_(4)^(2-)浓度增加,但氧化条件下释放出的Fe^(2+)被氧化为Fe^(3+)形式,并形成难溶的氢氧化物沉淀从地下水中除去,从而使地下水中Fe浓度降低。Due to the perennial mining of Daye iron mining area,the ecological environment and groundwater balance have been seriously damaged,Firstly,this paper reveals the regional pollutants distribution features by methods of components analysis and isotope tracing.Then the main hydrogeochemical evolution process,the migration process and pollution mechanism are discussed through the reverse geochemical sim-ulation.The result shows that both the groundwater and surface water in Daye mining area exist in the weak alkaline oxidation environment,and the hydrochemical type is mainly the HCO_(3)·SO_(4)-Ca type water.Carbonate and silicate hydrolysis are the main source of hydrochemical components in the study area,and they are affected by evaporite dissoluticn,acid mingning drainage,and domestic pollution of residents to va-rying degrees.Groundwater with elevated Fe and SO_(4)^(2-)-concentration is mainly distributed near the Hongs-han Creek tailings pond and slag deposit site.The concentration of SO_(4)^(2-)exceeds the standard(250 mg/L)at the monitoring site of Shangzou national control point DYTKQ04,while Fe concentration is low.Along the groundwater flow path,dedolomitization,ion exchange and pyrite oxidation occur,and SO_(4)^(2-)concentration in groundwater increases.Fe^(2+)released is oxidized to Fe^(3+)under oxidation conditions,and it is easy to form insoluble hydroxide precipitation.Fe concentration in groundwater is reduced.

关 键 词：地下水污染 水化学演化过程 铁 硫酸盐 水-岩相互作用 大冶铁矿区 

分 类 号：X523[环境科学与工程—环境工程]