Michael O. Rivett

Organic contamination of the Birmingham aquifer, U.K.

Abstract A survey of the organic-water quality of the Birmingham Triassic Sandstone aquifer was conducted using 59 supply boreholes. Additional shallow-groundwater quality data were obtained from 15 monitoring wells. Chlorinated solvents are widespread, in particular trichloroethylene which is detected in 78% of supply boreholes. Trichloroethylene is frequently observed at high levels with 40% of supply boreholes contaminated above 30 μg/l to a maximum of 5500 μg/l. Occasional high values are also found for 1,1,1-trichloroethane and perchloroethylene. The distribution of solvents is shown to be controlled by land use and hydrogeological factors. Contamination by organic chemicals other than chlorinated solvents is low in the supply boreholes. When high contamination does occur it is usually in the form of a petrogenic hump of unresolved contaminants in the chromatogram. The source of such contamination is probably (degraded) lubricating oils. Greater contamination by general organic chemicals is seen in the shallow groundwater samples, a reverse trend to the chlorinated solvents results.

Sustainable Groundwater Development

Abstract Estimated annual water availability per person in 2025 is likely to result in at least 400f the world’s 7.2 billion people facing serious problems with obtaining freshwater for agriculture, industry or human health (Gleick 2001). To meet present and future needs with the currently available surface and groundwater resources, while at the same time preserving terrestrial and aquatic ecosystems, will require a sustainable approach to managing water. This paper discusses the importance of groundwater resources in industrialized and developing countries, and the associated problems of over-abstraction and groundwater pollution, with the objective of defining sustainable groundwater development. It is concluded that sustainable groundwater development at global and local scales is achieved through the maintenance and protection of groundwater resources balanced against economic, environmental and human (social) benefits. This interpretation of sustainable groundwater development is incorporated into the methodologies currently emerging in Europe (the EU Water Framework Directive) and England and Wales (Catchment Abstraction Management Strategies). However, success in achieving future sustainable groundwater development will require a common understanding at the level of the individual based on information and education within a legislatory framework that promotes co-operation and self-responsibility.

Nitrogen processes in aquatic ecosystems

Nature of the problem * Freshwater ecosystems play a key role in the European nitrogen (N) cycle, both as a reactive agent that transfers, stores and processes N loadings from the atmosphere and terrestrial ecosystems, and as a natural environment severely impacted by the increase of these loadings. Approaches * This chapter is a review of major processes and factors controlling N transport and transformations for running waters, standing waters, groundwaters and riparian wetlands. Key findings/state of knowledge * The major factor controlling N processes in freshwater ecosystems is the residence time of water, which varies widely both in space and in time, and which is sensitive to changes in climate, land use and management. * The effects of increased N loadings to European freshwaters include acidifi cation in semi-natural environments, and eutrophication in more disturbed ecosystems, with associated loss of biodiversity in both cases. * An important part of the nitrogen transferred by surface waters is in the form of organic N, as dissolved organic N (DON) and particulate organic N (PON). Th is part is dominant in semi-natural catchments throughout Europe and remains a signifi cant component of the total N load even in nitrate enriched rivers. * In eutrophicated standing freshwaters N can be a factor limiting or co-limiting biological production, and control of both N and phosphorus (P) loading is oft en needed in impacted areas, if ecological quality is to be restored. Major uncertainties/challenges * The importance of storage and denitrifi cation in aquifers is a major uncertainty in the global N cycle, and controls in part the response of catchments to land use or management changes. In some aquifers, the increase of N concentrations will continue for decades even if efficient mitigation measures are implemented now. * Nitrate retention by riparian wetlands has oft en been highlighted. However, their use for mitigation must be treated with caution, since their effectiveness is difficult to predict, and side eff ects include increased DON emissions to adjacent open waters, N2O emissions to the atmosphere, and loss of biodiversity. * In fact, the character and specifi c spatial origins of DON are not fully understood, and similarly the quantitative importance of indirect N2O emissions from freshwater ecosystems as a result of N leaching losses from agricultural soils is still poorly known at the regional scale. * These major uncertainties remain due to the lack of adequate monitoring (all forms of N at a relevant frequency), especially - but not only - in the southern and eastern EU countries. Recommendations * The great variability of transfer pathways, buffering capacity and sensitivity of the catchments and of the freshwater ecosystems calls for site specific mitigation measures rather than standard ones applied at regional to national scale. * The spatial and temporal variations of the N forms, the processes controlling the transport and transformation of N within freshwaters, require further investigation if the role of N in infl uencing freshwater ecosystem health is to be better understood, underpinning the implementation of the EU Water Framework Directive for European freshwaters.

Transport of a dissolved-phase plume from a residual solvent source in a sand aquifer

Abstract The occurrence of groundwater contamination by chlorinated solvents is widespread throughout the industrialised world. Because these solvents have a density greater than water, the sources of contaminant groundwater plumes in many cases are expected to be pools and zones of residual solvent that are located below the water table. A tracer experiment designed to provide a simplified simulation of the above scenario has been conducted at the University of Waterloo Borden field site. A homogeneous block of sand containing residual solvent at 5% residual saturation of the pore space was emplaced 1 m below the water table. This source zone measured 1.5 × 1 × 0.5 m and contained a mixture of chloroform (TCM), trichloroethylene (TCE), perchloroethylene (PCE) and gypsum powder to provide sulfate as a conservative inorganic tracer. Subsequent groundwater flow through the source zone created a continuous plume of dissolved solutes down-gradient. The plume was monitored by a three-dimensional array of over 2300 sampling points and after 15 months extended 60 m from the source. This paper presents an overview of the experiment, with field results of source dissolution and dissolved-phase plume transport. The field results were selected to give an indication of the complexity of the observed field data. Some preliminary modeling of the data to estimate the approximate magnitude of dispersion parameters and comparison of these values with other tracer tests is presented.

Urban groundwater management and sustainability

Preface. I. Introduction. Towards Management and Sustainable Development of Urban Groundwater Systems: An introduction J. H. Tellam et al.- II Regional Overviews. Anthropogenic Changes to Hydrogeological Conditions in Urban Areas: New perspectives from Azerbaijan R.G. Israfilov.- Demands on, Condition, and environmental Problems of the Baku Municipal Water Supply A.Mammadova and Sh.I.Pashayeva.- Geoecological Problems in Azerbaijan A. B. Alekperov et al.- Sources of Groundwater Supply to Urbanized Areas in Azerbaijan: National development of groundwater resources F. Sh. Aliyev and F. S Askerov.- Optimaztion of Groundwater Usage for Urbanized rural Settlement Supply in Azerbaijan Yu. H .Israfilov et al.- Urban Groundwater Pollution in Turkey: A national review of urban Groundwater quality issues A. Baba and 0. Ayyildiz .-Groundwater Potential and Hydrogeological Characteristics of Corlu, Turkey I. Feda Aral.- Evaluation of Groundwater Over-Abstraction by Industrial Activities in the Trakya Region, Turkey: A Case of urban Groundwater resource Over-Abstraction A.OEngen and E. Tinmaz.-.A long-term Perspective on the Sustainable Development of Urban Groundwater Resources in Romania D. Galatchi.-III. Groundwater Flow.Integrated Hydrological Modelling for Sustainable Development and Management of Urban Water Supplies E. Zia Hosseinipour .- Estimating Evapotranspiration in Urban Environments K. Trout and M. Ross.-Reliability in Estimating Urban Groundwater Recharge through the Vadose Zone: Managing sustainable Development in arid and semiarid regions M. J. Friedel .- Urban Well-Field Capture Zones Delineated using Flow Structure Modelling D. Kuznetsov.- IV. Chemical Water Quality.Impacts of Sewer Leakage on Urban Groundwater: Review of a case study in Germany I. Held et al.- Contamination and Degradation of De-Icing Chemicals in the Unsaturated and Saturated Zones at Oslo Airport, Gardermoen, Norway B. Wejden and J. Ovstedal.-Aromatic HydrocarbonContamination of Clay Strata below a Petrochemical Site, UK: Organic contaminant migration in clay aquitards R. A. White et al.-Baseline Groundwater Quality in the Coastal Aquifer of St. Lucia, South Africa M. Simonsen Bjorkenes et al.- Hydrochemical Quality of Groundwater in Urban Areas of South Portugal A. Chambel et al.- Issues of Radioactivity and Sustainable Development within Urban Groundwater Systems in Russia L. M. Rogachevskaya.- Risks Posed by Unsanitary Landfill Leachate to Groundwater Quality: Corlu (Trakya) Turkey E.Tinmaz and A. OEngen.-Agricultural Influences on Groundwater used for Water Supply in the Caucasus Mineral Water Region O.A. Karimova.- Environmental Problems Associated with Utilization of Mineral Waters in Urbanized Areas of Azerbaijan M. M. Ismailova.- Conclusions from a negative Tracer Test in the Urban Thermal Karst Area, Budapest, Hungary A. Eroess et al.- V. Biological Water Quality.Monitoring and Managing the Extent of Microbiological Pollution in Urban Groundwater Systems in developed and developing Countries A.A. Cronin et al.- Microbial Pollution of Groundwater in the Town of Walkerton, Canada: Implications for the development of appropriate aquifer protection strategies K. W. F. Howard.-Effects of Artificial Stormwater Infiltration on Urban Groundwater Ecosystems: Ecological issues in urban groundwater T. Datry et al.- VI. Remediation.Organic Contaminant Remediation in Urban Groundwater: A review of Groundwater remediation technology development M. O. Rivett.- Recent Approaches for Urban Groundwater Pollution Remediation: Analysis and Recommendations D. Klaffke.-Reducing the Groundwater Pollution Risk in the Mining and Industrial Regions of Chiatura and Kazreti, Georgia: Remediation of mine-related tailings and wastes Sh. Petriashvili and D. Chutkerashvili.- The Removal of Nitrate and Pesticides from Contaminated Water S. Asian and A. Turkman.- VII. Engineering. Chemical and Geotechnical Problems Associated with

Groundwater Pollution: The Emerging Role of Environmental Forensics

In recent years, subsurface forensics has emerged as a definable subject area in the field of contaminant hydrogeology or groundwater pollution. For the purpose of this chapter, a definition modified from Morrison and Murphy1 will be employed. Subsurface forensics will refer to: ‘the systematic and ...