某铬渣堆污染地下水六价铬污染特征与迁移转化规律研究  

Pollution characteristics,migration and transformation of hexavalent chromium in groundwater of a chromium slag

作　　者：吕永高[1] 蔡五田[1] 杨骊 边超[1] 李敬杰[1] 王明国 LYU Yonggao;CAI Wutian;YANG Li;BIAN Chao;LI Jingjie;WANG Mingguo(Center for Hydrogeology and Environmental Geology Survey,China Geological Survey,Baoding,Hebei 071051,China)

机构地区：[1]中国地质调查局水文地质环境地质调查中心,河北保定071051

出　　处：《水文地质工程地质》2024年第3期180-190,共11页Hydrogeology & Engineering Geology

基　　金：中国地质调查局地质调查项目(DD20230456,DD20160310,DD20242422)。

摘　　要：我国铬渣堆历史存量较大,渣堆渗滤液中的六价铬[Cr(Ⅵ)]毒性大、迁移性强。为探究污染源特征、场地水文地质条件和水文地球化学过程综合作用下Cr(Ⅵ)在地下水中的迁移转化规律,文章以某铬污染场地为例,通过水样采集与分析,利用克里格插值、因子分析、水化学计算、Piper三线图和离子比等方法查明地下水中Cr(Ⅵ)的空间分布与水化学特征,识别水体中Cr(Ⅵ)的主要赋存形式,并探讨影响Cr(Ⅵ)在地下水中迁移转化的主控因素。结果表明:(1)场地40 m以浅的2个含水层均受到了Cr(Ⅵ)污染,污染范围和程度差异显著。(2)Cr(Ⅵ)在地下水中主要以和Cr_(2)O_(2)-7 HCO_(3)^(-) SO_(4)^(2-)2种形式存在,浓度极低,高浓度Cr(Ⅵ)水点的阴离子以和为主,阳离子以Na^(+)和Ca^(2+)为主。(3)降水淋滤SO_(4)^(2-) HCO_(3)^(-)和渗漏导致含有大量Na+、和Cr(Ⅵ)的渗滤液进入地下水,使地下水pH值升高;高浓度的和弱氧化环境下铁氧化物的溶解可以促进Cr(Ⅵ)在地下水中的迁移;锰氧化物和有机质通过氧化还原反应改变地下水中Cr(Ⅵ)浓度;浅层地下水的蒸发浓缩作用加剧Cr(Ⅵ)在地下水中的富集。研究成果可为铬渣类污染场地的风险管控与后期修复提供有力支撑。The historical stockpile of chromium slag in China is large,and the hexavalent chromium in slag leachate is highly toxic and migratory.In order to investigate the migration and transformation pattern of Cr(Ⅵ)in groundwater under the combined effect of pollution source,site hydrogeological condition and hydrogeochemical process,a hexavalent chromium contaminated site was taken as an example in this study,the spatial distribution,hydrogeochemical characteristic,occurrence form and proportion of Cr(Ⅵ)in groundwater,and the main factors affecting migration and transformation of Cr(Ⅵ)are analyzed by sampling and testing groundwater samples,and the combination using of methods such as Kriging interpolation,factor analysis,hydrogeochemical calculation,Piper diagram and ion ratio.The results show that(1)the two aquifers below ground surface 40 m are polluted by CrO_(4)^(2-)Cr(Ⅵ),but the size and degree are different obviously.(2)The main forms of Cr(Ⅵ)in groundwater are HCrO_(4)^(-) Cr_(2)O_(2)-7and,content is extremely low,and the anions of samples with high Cr(Ⅵ)concentration are mainly HCO_(3)^(-) SO_(4)^(2-)and,the cations are mainly Na+and Ca2+.(3)Precipitation leaching and seepage result in the leachate SO_(4)^(2-)containing large amounts of Na+,and Cr(Ⅵ)entering groundwater.The increasing pH,high concentrations HCO_(3)^(-)of and dissolution of iron oxides under low oxidizing environment in groundwater can facilitate the migration of Cr(Ⅵ).Manganese oxides and organic matter are able to change Cr(Ⅵ)content through redox reaction.Evaporation also plays an important role on the enrichment of Cr(Ⅵ)in groundwater.The results of this research can provide strong support for risk management and post remediation of chromium slag contaminated sites.

关 键 词：污染场地 六价铬 形态特征 因子分析 迁移转化 

分 类 号：X523[环境科学与工程—环境工程]