论场地土壤和地下水污染调查与风险评价的程序和内容

通过分析、对比发达国家场地污染调查与风险评价技术流程的大量信息,结合工作实践,充分考虑我国的实际情况,视土壤和地下水为相互联系的一个整体,提出了我国现阶段场地尺度土壤和地下水污染调查与风险评价的技术程序和工作内容。     

Experimental simulation of soil contamination by arsenolite

Column experiments were conducted to experimentally simulate the initial conditions at a field site where legacy As contamination was caused by application of arsenolite as a herbicide to the soil. The experiments were designed to investigate the influence of herbicide loading and carbonate gravel cover on the release of As to, and the As adsorption capacity of, the background soil. The results showed that the As release from the doubly spiked column was three times higher than for the singly spiked columns. The addition of gravel above the herbicide layer halved the leaching time needed for peak As release from the soil. Extrapolation of the experimental data predicted that the columns with carbonate gravel should retain more As (15.6 g for column FWAsG and 12.3 g for column F2AsG) than the column without gravel (0.13 g for column FWAs). The results also indicated the thickness of the arsenolite layer was not important in terms of the As retention capacity of the soil columns. Arsenate was detected and quantified in the effluent solutions by ion chromatography. The data indicated As(III) dominated in the effluents for the first 180 pore volumes (PVs). After 180 PVs, As(III) almost disappeared and As(V) dominated in the effluents. The unexpected high As peak release from the doubly spiked column FW2AsG indicated that solutions having higher As(III) concentrations had a higher capability to dissolve arsenolite, possibly through solute–solute interactions or polymerization. Effluent solution Eh–pH values indicated that As(V) was the thermodynamically stable form of As throughout the experiments. Therefore, As(III) dominance in the initial column effluent solutions was kinetically controlled.     

Lead contamination of soil along road and its remediation

With a rapid development of road systems and an associated drastic increase in number of automobiles, the traffic has induced more and more obvious environmental pollution such as noise, dust, emission and heavy metal contamination. Lead, as one of the most harmful heavy metal contaminants, can execute a significant impact on soil quality and plant growth, depending on its form, as well as its transport and accumulation in soil. This paper describes the source and characteristics of Pb contaminant in soil along a road, and reviews the results of research on remediation of Pb-contaminated soils, aiming at identifying promising approaches to soil remediation along roads.     

Reaction of soil enzymes and spring barley to copper chloride and copper sulphate

Study was carried out to compare the effect of the degree of contamination of soil with copper on the soil enzyme activity, depending on the type of chemical compound with which a metal reaches the soil and on the method of soil use. An effect of increasing doses of copper on growth and the development of spring barley has been studied. The study was carried out as a pot experiment on two types of soil: loamy sand and light loam. Copper was introduced to soil as copper(II) sulphate(VI) and copper(II) chloride at four doses: 150, 300, 450 and 600 mg Cu²⁺ kg^?1 d.m. of soil. Soil without copper was used as a control sample. The experiment showed that contamination of soil with copper applied as CuCl₂ and CuSO₄·5H₂O upset the homeostasis of soil. Dehydrogenases and urease were the most sensitive to contamination of soil with Cu²⁺, both as copper(II) chloride and as copper(II) sulphate(VI), and acid phosphatase and alkaline phosphatase were the least sensitive. Greater changes in enzymatic activity were observed in loamy sand than in light loam. The differences in the impact of copper(II) sulphate(VI) and copper(II) chloride on the soil microbiome were relatively small, because mean ED₅₀ for copper(II) chloride was 341 mg Cu²⁺ kg^?1 d.m. of soil, and for copper(II) sulphate(VI) it was 364 mg Cu²⁺ kg^?1 d.m. of soil. This inhibitory effect of copper persisted throughout the period of the experiment. The sensitivity of spring barley to copper compounds was lower than the enzymes under study.     

石油类污染场地土壤与地下水污染调查实例分析

以冀中平原某石油类污染场地为例,从污染源分布勘察、场地水文地质模型建立、土壤及地下水的现场调查入手,采用物探、坑探、钻探综合调查技术和定深取样等一些取样方法,对不同深度土壤及地下水的有机污染进行调查和样品分析。结果表明:整个场地的土壤和地下水受到不同程度的污染,30m深度内包气带和饱水带已被污染,50m深度的地下水中有有机污染物检出,石油类场地的污染特征主要表现为土壤及其地下水中含有高浓度单环芳烃和卤代烃。且单环芳烃在土壤与地下水中的浓度高于其它有机污染物。     

水溶性污染物在土壤中转化的原位实验方法

建立了一种研究水溶性污染物在土壤中运转化的原位实验方法，该方法已成功地应用于研究黄土中氨氮的运移转化规律，克服了土柱实验存在的破坏土壤结构及氧化还原电位发生变化等所引起的实验误差。     

土壤重金属污染评价方法研究进展

从技术应用的角度,将土壤重金属污染评价方法分为传统的方法和基于GIS的评价方法两大类.本文阐述了评价方法的研究进展,分析了主要评价方法的优缺点,最后对评价方法做出了展望.     

土壤元素污染等级划分方法及其应用

以土壤中有毒有害元素含量为依据,以元素污染叠加程度为准则,提出了土壤污染等级标准的确定方法。长江三角洲、福建沿海地区的试验研究表明,表、深层土壤成土母质具有同源性,元素含量具有较好的相关性,深层土壤基本不受人类活动的影响,基于深层土壤元素含量确定的地球化学基准值是土壤污染等级划分的基础依据,据此建立了长江三角洲地区土壤污染等级标准,取得了该地区土壤污染等级划分结果。根据土壤污染成因及其生态环境意义,厘定了不同土壤污染等级的内涵。研究认为土壤污染等级区的生态效应需综合各种因素进行分析。     

Study on soil heavy metals contamination of a lead refinery

The contents of Pb, Cd, Cr, As, and Hg was investigated in the neighboring areas of a lead smelting enterprise and the metals contamination of soil was evaluated with the methodologies of the single factor index and Nemerow integrated index. It is found that the content of heavy metals in the neighboring areas has no obvious difference from the reference points. And the soil contamination of heavy metals varies by elements, the contamination index follows the pollution order： Cd〉Hg〉Cr〉As〉Pb. The pollution degree of Cd is at high level and Hg at low level, but Cr and As reached the warning level. Therefore, the lead smelting enterprises should not only control lead but also other heavy metals as Cd.     

Pesticide transport and transformation modeling in soil column and groundwater contamination prediction

Pesticide transport and transformation were modeled in soil column from the soil surface to groundwater zone. A one dimensional dynamic mathematical and computer model is formulated to simulate two types of pesticides namely 2,4-dichlorophenoxy acetic acid and 1,2-dibromo 3-chloro propane in soil column. This model predicts the behavior and persistence of these pesticides in soil column and groundwater. The model is based on mass balance equation, including convective transport, dispersive transport and chemical adsorption in the phases such as solid, liquid and gas. The mathematical solution is obtained by finite difference implicit method. The model was verified with experimental measurements and also with analytical solution. The simulation results are in good agreement with measured values. The major findings of this research are the development of the model which can calculate and predict the concentration of pesticides in soil profiles, as well as groundwater after 4, 12, 31 days of pesticide application under steady state and unsteady water flow condition. With the results of this study, the distribution of various types of pesticides in soil column to groundwater table can be predicted.     

中国典型有机污染场地土层岩性和污染物特征分析

目前我国存在大量待修复场地,其分布具有一定的规律性和区域性,场地地层系统结构复杂、渗透性空间异质性显著,污染物种类复杂。总结场地典型土层结构和典型污染物有助于有针对性地开展修复技术的研发。为此,本文收集并整理了全国136处有机污染场地相关资料,对其地域性、地层及污染物特征总结如下:目前我国已经开展调查与修复的有机污染场地主要集中在京津冀和沪宁杭地区;有机污染场地土层基本都含有黏土等低渗透介质,而且都具有非均质性,其中67%场地土层有强非均质性;沪宁杭地区场地土层渗透性总体低于京津冀和辽中南地区,此外我国京津冀和辽中南地区场地调查深度(20.3 m)总体大于沪宁杭地区(12.8 m);我国有机污染场地地下水中最常见的有机污染物种类为氯代溶剂,依次为氯代烷烃类(场地数量占比84%)、氯代苯类(场地数量占比46%)和氯代烯烃类(场地数量占比33%);最常见的3种氯代溶剂依次为二氯乙烷、一氯苯和三氯甲烷。     

山东省东部地区土壤地球化学特征及污染评价

以山东省东部地区农业生态地球化学调查取得的区域土壤地球化学数据为依据,研究了区内54种元素或指标的土壤地球化学基准值和背景值与全国土壤的差异。通过对比区内土壤基准值与背景值的变化,认为本区大部分元素或指标在表层土壤中的含量继承了成土母质,后期人类活动对其影响较小,Zn、Pb、Cu、Se、Cd、S、P、Hg、N、OrgC等元素或指标在表生作用或人类活动等因素影响下,其分布分配特征产生明显变化。本文通过对表层和深层土壤元素相关系数的研究,认为深层土壤元素地球化学含量可表征表层土壤原始沉积的地球化学含量;讨论了人为活动导致土壤污染的评价方法,莱州—招远—烟台和牟平—乳山金矿集中区以及人口密集的城镇地带表层土壤中Hg、Cd、Pb、As、Zn、Se、S等元素污染严重。地质背景和人类活动(采金污染、工业生产、城市人口密集生活等)的共同作用,是造成环境中有害元素含量较高的主要原因。     

Using soil and contaminant properties to assess the potential for groundwater contamination to the lower Great Lakes,USA

Contaminant risk factors in surface soil were evaluated within the urbanized Rouge River watershed in southeastern Michigan, USA, which includes metropolitan Detroit. An analytical risk factor model and Geographic Information Systems overlays were used to quantify and characterize the potential impacts of five categories of contaminants including DNAPLs (dense nonaqueous phase liquids), LNAPLs (light nonaqueous phase liquids), PAHs (polynuclear aromatic hydrocarbons), PCBs (polychlorinated biphenyls), and lead. The results indicate that DNAPL compounds released into sand, moraine, and sandy and silty clay soil types have the greatest potential to affect groundwater, and impact the Great Lakes ecosystem and the public health.     

Impact of lead contamination on the engineering properties of clayey soil

Clay liners are widely used as barriers to arrest the migration of pollutants. These liners are subjected to leaching of various chemicals and hazardous wastes. Migration of heavy metals through the liner material may lead to changes in the soil properties and this, in turn, may affect the performance of liners. In this paper, the change in index and engineering properties of clayey soil due to migration of lead is presented. Pronounced changes in soil properties are noticed when the soil is contaminated with high concentrations of lead. The findings from the present study are important while designing liners in landfills used for containment of pollution due to heavy metals and hazardous wastes.     

非饱和土壤溶质迁移转化模型参数优化估算

在分析非饱和土壤中水分和溶质迁移转化规律的基础上,采用与坐标网格相适应的分块连续作用的水动力函数,研究模型参数最优化估算技术.运用Gauss-Newton最小化计算的Levenberg-Marquardt修正法来实现反求模型的迭代问题.该方法被应用于估算一维土柱和二维土槽试验研究模型的参数,探讨了参数给定与估算数量对参数的置信区间和预测效果的影响.经验证表明,参数优化估算技术是可行的,以此参数进行模型预测,其结果是可信的.