Cr、Ni、Cu和Cd在珠三角某区域工业污染场地包气带和潜水层中的迁移规律

发布时间：2018-04-05 12:08

本文选题：重金属　切入点：迁移规律　出处：《环境工程学报》2016年12期

【摘要】：为了探索污染场地"土壤-潜水含水层岩土-潜水"系统中同种重金属在3种环境介质中的定量关系和迁移规律,在珠三角某区域46个可能受Cr、Ni、Cu和Cd污染场地建设了61眼地下水监测井,同址采集61组表层(0~20 cm)土壤、潜水层岩土和潜水样品,并从3个污染场地采集了直径19 cm,高分别为103、81和79 cm的3个原状土柱,用于土柱淋溶实验,研究了土柱中Cr、Ni、Cu和Cd在垂直剖面上的形态分布特征和淋溶特征。结果表明:潜水中Cr、Ni、Cu和Cd含量与表层土壤和潜水层岩土中弱酸提取态含量间存在定量关系,最佳拟合函数均为三次函数,特别是Cr、Cu的函数有很好的相关性(决定系数R2均大于0.97)。每20 cm一层分析原状土柱中Cr、Ni、Cu和Cd的全量和形态分布,同种重金属在3个原状土柱表层土壤中全量和弱酸提取态含量占整个土柱比例均最高,均超过50%,土柱中Cr、Ni、Cu和Cd的全量和弱酸提取态含量随着土柱深度增加都明显减少。土柱淋溶实验结果表明,淋出液中Cr、Ni、Cu和Cd含量与表层弱酸提取态含量显著相关,黏粒含量高和阳离子交换量大的土壤对Cu的淋溶有抑制作用。建议在重金属污染场地调查和修复时,充分考虑弱酸提取态在"土壤-潜水含水层岩土-潜水"系统中的"桥梁"作用。
[Abstract]:In order to explore the quantitative relationship and migration law of the same heavy metals in three kinds of environmental media in the system of "soil-phreatic aquifer rock-soil-diving" in polluted sites,A total of 61 groundwater monitoring wells were constructed in 46 sites in the Pearl River Delta region that may be contaminated by Cr, Ni, Cu and CD. 61 groups of topsoil, submersible rock, soil and diving samples were collected at the same site.Three undisturbed soil columns (19 cm in diameter and 79 cm in height) were collected from three contaminated sites for leaching experiments. The morphological distribution and leaching characteristics of Cr, Ni, Cu and CD in soil column on vertical profile were studied.The results show that there is a quantitative relationship between the contents of Cu and CD in the subsurface soil and the content of weak acid in the surface soil and the rock soil of the phreatic layer, and the best fitting functions are all cubic functions, especially the function of Cr-Cu has a good correlation (the determining coefficient R2 is all greater than 0.97).Every 20 cm layer, the total amount and speciation distribution of Cr, Ni, Cu and CD in the undisturbed soil column were analyzed. The contents of the same heavy metals in the surface soil of the three undisturbed soil columns were the highest in the whole soil column, and the proportion of the total and weak acid extractable state in the surface soil of the three columns was the highest.The contents of Cu and CD in the soil column decreased obviously with the increase of soil column depth.The results of soil column leaching experiments showed that the contents of Cu and CD in the leaching solution were significantly correlated with the contents of weak acid extracts in the surface layer. The soil with high clay content and high cation exchange capacity could inhibit the leaching of Cu.It is suggested that in the investigation and remediation of heavy metal contaminated sites, the role of weak acid extraction as a bridge in the system of "soil-submersible aquifer geo-soil-diving" should be fully considered.
【作者单位】：华南理工大学环境与能源学院;工业聚集区污染控制与生态修复教育部重点实验室;广州市水资源与水环境行业工程技术研究中心;
【分类号】：X53;X523

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