Contaminated Land: Implications for Water Pollution

The water environment is often neglected in the assessment of the impact of contaminated land and its redevelopment. The lack of effective legislative controls over derelict contaminated land areas and the poor appreciation of water pollution by developers and planning authorities in the undertaking and controlling of site redevelopment has severely hindered effective clean-up and protection of groundwater and surface waters.
The formation of the National Rivers Authority, the publication of the House of Commons Environment Committee's report and the implementation of the Environmental Protection Act 1990 have given the subject a new impetus. The preparation of registers by local authorities, which identify contaminated land areas, could be enhanced by the National River Authority's assessment of key sites. It is hoped to initiate clean-up by cooperation, but the testing of legislative powers has been encouraged by the Government, if only to reveal their inadequacies.     

Contamination of the Chalk Aquifer by Chlorinated Solvents: A Case Study of the Luton and Dunstable Area

A detailed investigation of contamination by chlorinated solvents of the Chalk Aquifer underlying the towns of Luton and Dunstable was undertaken to assess the extent, causes and mechanisms of pollution. The research programme incorporated land-use surveys, regional groundwater surveys, monitoring of groundwater abstraction points and aquifer profiling by means of the drilling of observation boreholes, the analysis of the recovered core material and the depth sampling of these and other boreholes.
Low-level solvent contamination of the Chalk Aquifer was found to be widespread with 'hotspots'of higher concentrations. At the drilling sites, both the saturated and unsaturated zones were contaminated with solvents, although free product was not observed. The presence of an additional contaminant, oil, at some sites was noted to influence the distribution of solvents within the aquifer.
Clean-up of the aquifer is not a practical option, and treatment of the groundwater at the abstraction points has been adopted.     

Chlorinated Solvents in UK Aquifers

The paper reviews background data on chlorinated solvents and all published data on chlorinated solvents in UK groundwaters. New data from an aquifer-wide survey of the organic water quality of the Birmingham aquifer (carried out by the University of Birmingham and the Water Research Centre (WRc)) show that contamination by chlorinated solvents is extensive and is greater than that observed in previously published UK studies. Trichloroethylene contamination is particularly apparent in the Birmingham aquifer, with 40% of the boreholes sampled containing waters above the new UK limit for this contaminant. Fortunately the Birmingham aquifer is not used for public supply. Land use and hydrogeological factors are shown to influence the contamination observed in particular boreholes. The difficulties associated with locating contaminated zones in aquifers, due to the immiscible flow of chlorinated solvents, are indicated. It is concluded that the occurrence of chlorinated solvents in groundwaters makes a significant contribution to the poor water quality of many UK aquifers that underlie, or are close to, urban and industrial areas.     

固定化微生物修复石油污染土壤特性试验

利用梯度稀释法分离筛选原油降解混合菌,采用吸附法将混合菌固定在砾石和草炭土上,探讨固定化混合菌对土壤石油烃的去除效果。结果表明:分离得到的混合菌8-2,菌群结构简单,石油烃降解率可达52.1%。与砾石相比,草炭土所固定的微生物数量和活性较高,可达1.3×108 cfu/g和0.24A487。草炭土固定的混合菌8-2,修复含油量为30g/kg的污染土壤30d后,石油烃降解率达28.4%,高于游离降解菌的24.3%。固定化载体草炭土在修复过程中起到了微生物缓释剂的作用。     

Contaminated Land Remediation: Economics v Liability

Chemical investigations of contaminated land can be expensive and yet still leave the landowner unaware of his/her full environmental liability. An approach to an effective means of planning chemical investigations is described by a case study of a contaminated site near London. This approach limits environmental liability in a cost-effective manner.
One of the main problems encountered in assessing the degree of contamination of land for the purposes of technical design, and ultimately for developer confidence, is the lack of recognized UK standards for acceptable levels of contaminants.
Using a second case study relating to a large contaminated site in the Midlands, the paper describes how a set of site-specific standards, for soil and water, was derived and used to develop a reclamation strategy for an 81-ha site. The case study also demonstrates the approach which was adopted in handling a large amount of analytical data and other quantitive information needed to produce a set of 'constraint models'. From these constraint models, the strategy for reclaiming the site has been developed.     

泥炭生物反应墙构建及修复地下水中石油烃

为有效修复地下水中溶解态石油烃污染物,在研究填充介质配比基础上,分别利用低温石油烃降解菌-泥炭-粗砂和泥炭-粗砂构建了泥炭生物反应墙和泥炭反应墙,考察了反应墙对地下水中BTEX、PAHs的修复效果.结果表明,泥炭与粗砂最适体积比为20:80,此时墙体渗透系数为1.17×10-4m/s,有效空隙率为7.5%;泥炭反应墙对...     

Private Sector Funding for Redevelopment of Contaminated Land

C urrent D epartment of the E nvironment (D o E) guidelines under the Derelict Land Grant Scheme and the new City Grant are discussed together with grant coverage, procedures and policy.     

Contaminated Land Remediation in the UK with Reference to Risk Assessment: Two Case Studies

The approach to land reclamation in the UK has traditionally relied upon the use of cover and concealment, which can leave a legacy of problems below the ground. Alternatively, the bulk export of materials to licensed landfill has often been used, but this (a) simply transfers a problem, (b) can cause considerable disruption, and (c) is becoming increasingly expensive. Remedial strategies involving the use of barrier systems or off-site removal both have their place in the efficient and economic development of contaminated sites. However, there is now increasing interest in the use of on-site technology which can provide cost savings and by treating, destroying or stabilizing contamination, can serve to minimize future liabilities. The design, costing and application of treatment, as opposed to cover or disposal, depends fundamentally on understanding the problem and evaluating the capabilities and availability of appropriate technologies. With reference to UK case studies, this paper highlights some of the options available and routes taken in order to achieve site-specific, commercially-acceptable, remedial responses.     

Current Developments in Contaminated Land Treatment Technology in the UK

This paper reviews recent developments in contaminated land treatment (soil and groundwater) in the UK, particularly with regard to:

• (i) 

  The combination/integration of individual soil-treatment unit processes and the use of 'extensive' technologies;
• (ii) 

  UK demonstration and emerging projects including those in the NATO/CCMS (Committee for Challenges to Modern Society) Pilot Study on Research, Development and Evaluation of Remedial Action Technologies for Contaminated Soil and Groundwater; and
• (iii) 

  Contaminated land treatment technology research and development in the UK.

     

Contaminated Land and Aquifer Protection

The paper discusses the definition of contaminated land, its legislative controls, how it is identified and how a hazard ranking exercise may be carried out on a property portfolio in order to deal constructively with the problem of contaminated land. Such land is important because it can have substantial financial penalties attached to its investigation and remediation. The potential liabilities now arising from environmental impairment are such that anyone involved in the acquisition, ownership or disposal of land has to take an interest in it. The legislative background and environmental policy considerations which affect contaminated land are described, as well as the role of the National Rivers Authority in dealing with the subject. The principal types and sources of contaminated land are identified and current guidelines and standards for dealing with it are discussed. A technique developed for Scottish Enterprise whereby a property portfolio can be ranked in order of its potential hazard by combining the sensitivity of a site with its contamination potential in order to define environmental risk is described, and the necessity to seek professional and experienced advice in evaluating the consequences of contaminated land is highlighted.     

Overview of Clean-Up Methods for Contaminated Sites

The selection of clean-up methods for contaminated land depends upon the nature and degree of contamination and on standards for clean up. There have been two approaches to clean-up standards, namely 'multifunctionality', where the site is cleaned up to a standard suitable for any use, and the 'end use'approach, as used in the UK, where clean up is to a standard suitable for the immediate use proposed for the site.
Clean-up options fall into four categories: (i) excavation and off-site removal; (ii) encapsulation and cover; (iii) retention of contaminated soil on site after treatment; and (iv) removal of contaminants from soil and reuse of cleaned soil on site.
In the UK, clean up has been dominated by off-site disposal and encapsulation/cover, while soil treatment techniques have been used mainly in the US and some European countries such as the Netherlands. This is largely as a result of the availability and relatively low cost of landfill in the UK and the lesser importance attached to date to groundwater considerations.
Soil treatment processes include biological, physicochemical, and thermal processes, all generally of much higher cost.     

重金属锌污染淤泥质粉质粘土物理特性试验研究

重金属污染在我国已受到普遍关注,而对重金属污染土的物理特性的研究还处于起步阶段。采用南京地区特有的粉质粘土、长江漫滩相淤泥质粉质粘土,进行相关的重金属锌污染后的物理特性研究。通过室内添加硝酸锌溶液配制3种不同浓度的重金属锌污染土,并进行土壤污染前后粒度成分、液塑限、活动度、土粒比重以及pH值等试验的测试分析,研究比较了粉质粘土污染前后随着重金属锌的浓度不同其相关物理性质的变化规律。试验表明,随着Zn浓度的增加,土粒比重,液塑限,粉粒含量和pH值减小,而粘粒含量和塑性指数呈增大趋势。其土体的活动度也随着Zn浓度的增加在不断的降低,并且降低趋势逐渐减缓。     

地下水开采引起的地面沉降计算方法及分析

在Terzaghi一维固结理论的基础上结合修正的Kozeny-Carman方程,提出了适用于实际地层的、可考虑地下水类型和疏干情况及渗透系数随沉降发生变化的一维沉降计算方法。通过Fortran编写计算程序,分析了北京东南部区域的地面沉降量并与实测结果进行对比。结果表明:研究区域内在过去5年间,监测点的沉降计算结果与实测结果趋势基本一致,证明了该方法的合理性;地下水超采导致的地面沉降约占总沉降的80%;地下水类型和渗透系数均对沉降计算有影响,但地下水类型对承压水含水砂层分布较多且厚度较大的计算点的沉降计算影响较大,渗透系数对黏性土层分布较多且厚度较大的计算点的沉降计算影响较大。     

地质环境变异引起的建筑物裂缝分析

介绍了四个地质环境变异导致的工程事故。诸事故的肇事原因都与水有关,一种是地下水被抽走,后又回灌,从而在土层内形成塌陷;一种是潜流的强力冲刷造成地基塌陷;一种是少见的大旱使膨胀土发生干缩;一种是土壤中碱液浓度过大造成土壤湿陷。这些现象非常少见且难以预料,对勘察设计者具有指导意义。     

综述地面沉降对埋地燃气管道的影响研究

文章综述了国内外埋地管道受力的理论研究,阐述管道应力分析中常用的受力模型与数值模拟方法,重点分析了埋地燃气管道受力特点和防护对策,指出了目前研究现状中存在的问题。     

土壤污染防治法背景下的城乡绿地系统建设：趋势与对策

《中华人民共和国土壤污染防治法》的颁布标志着中国将形成完善的土壤污染防治法律体系,建立从污染土壤调查、修复、风险防控、监测到场地再利用,从环境标准到规划管理的全方位制度。生态文明制度建设的宏观背景,再加上中国土壤污染严重、规模大、修复难、成本高、周期长等特征,将导致大量污染场地转变为绿地或生态用地,最终对绿地系统的数量与规模、布局与功能、规划与管理、环境质量标准等多个维度产生实质性影响。分析这一趋势,对其影响提出预判,最终提出对策建议。