TB 01 - Introduction to an integrated approach to the investigation of fractured rock aquifers contaminated with non-aqueous phase liquids (2002)

This bulletin is the first of a series which supports an integrated approach to the investigation of non-aqueous phase liquid (NAPL) contaminants in fractured rock systems. It describes techniques and procedures for obtaining data to manage contaminated groundwater.

Contamination of fractured rock aquifers by NAPL is a worldwide problem. The resulting groundwater contamination is difficult to manage, due in part to the problems associated with collecting the necessary data to understand contaminant behaviour within the system properly.

The purpose of this bulletin is to introduce some concepts and terminology to those who may have an interest in managing sites involving contamination in fractured rock systems.

TB 02 - Multilevel sampling systems (2002)

This Bulletin describes multilevel sampling systems for characterising contaminated groundwater.

Contaminated groundwater can present considerable problems for landowners: it can occur at significant depth; sources of the contamination are not often obvious; it can migrate from one property to another; and groundwater flow directions can be altered because of seasonal variations or pumping. In order to assess risk and liability associated with contaminated groundwater, landowners must be able to characterise both the nature and extent of any contamination.  The use of multilevel sampling systems allows landowners to optimise the amount of information they can obtain from their boreholes.

TB03 - Principles and Practice for the Collection of Representative Groundwater Samples

Groundwater sampling is a fundamental part of most site characterisation programmes. In the context of contaminated land and groundwater assessment, groundwater samples are usually collected for chemical and microbiological analysis upon which future decisions or judgements may be made regarding the suitability of the groundwater for a specific use (e.g. potable or industrial), source and assessment of contamination, design and performance assessment of remediation programmes, asset value, liability and long-term monitoring needs.

This bulletin outlines the principles and practice governing the collection of representative groundwater samples, by understanding the source and mitigating the effects of, potential errors occurring during the sampling process.

TB04 - Parameterisation of Aquifer Hydraulic Properties: A Contaminant Hydrogeology Perspective

This technical bulletin explores various tests that can provide estimates of aquifer hydraulic properties at a scale appropriate for the different needs of contaminant hydrogeologists.  Traditional (i.e. large scale) pumping tests do not provide data at a scale appropriate to effectively understand and manage many contaminant situations.  Subsequently, other established methods are examined that can be used or adapted to provide comparatively high-resolution information on hydraulic properties at reasonable cost, with an assessment of some aspects of data quality.

TB 05 – The use of geophysical investigation techniques in the assessment of contaminated land and groundwater (2007)

Given limited resources and time constraints, site investigations for contaminated land and groundwater assessments need to generate relevant high quality data in an efficient and cost-effective manner. One important outcome of site investigations should be sufficient data to construct a robust and representative site conceptual model incorporating site history, buried infrastructure, geology, hydrogeology, dissolved contaminant and/or non-aqueous phase distribution and the interrelationships between these components. Without such understanding, it is difficult to establish the spatial resolution of data needs and developing a contaminant management and/or remediation strategy may prove less effective than intended.

This bulletin presents a survey of a representative range of geophysical site investigation methods, which may be used for contaminated land and groundwater assessments. It includes an analysis of well established and relatively new geophysical techniques, and illustrates their utility and application for site characterisation.

TB 07 - Improving the reliability of contaminated land assessment using statistical methods: Part 1 (2004)

Proper management of contaminated land requires an understanding of site conditions and of the nature and distribution of contaminants. This understanding is derived from site characterisation activities, which typically include sampling of surface and sub-surface soils and water. It is often assumed that the results obtained from these samples are representative of the actual ground and contaminant conditions but, this is not necessarily the case, due to heterogeneities in the site and uncertainties in the measurements.

This bulletin is designed to introduce some basic statistical methods which can be used to help quantify uncertainties, allow for heterogeneity, and provide confidence in making decisions when managing contaminated land.

TB 09 - Stabilisation/Solidification Treatment and Remediation: Part 1: Summary of the State of Practice Reports I-IV STARNET (2004)

This bulletin summarises the first four State of Practice Reports produced by STARNET. STARNET was an EPSRC funded Network on ‘Stabilisation/Solidification Treatment and Remediation’. The Reports presented the state of practice of stabilisation/solidification technologies in the UK (in 2004), and form part of the activities of STARNET. The purpose of these reports is to identify the knowledge gaps and future research needs in this field.

The first three State of Practice Reports focus on Binders and Technologies. Part I describes basic principles of available binders and technologies in the UK, Part II investigates research activity in this area, whilst Part III reviews the practical demonstrations of S/S technology in the UK through field trials and commercial applications. The final part of this Bulletin, Part IV, reviews the current practice in test methods and performance criteria used to assess S/S materials.

TB 11 - A practical guide to investigating DNAPL releases in the subsurface (2004)

Dense non-aqueous phase liquids (DNAPLs) are heavier-than-water organic liquids that have been widely used in industry from the early 1900s to the present. DNAPLs are only slightly soluble in water, and therefore exist in the subsurface as a separate fluid phase, immiscible with both water and air. Unlike light non-aqueous phase liquids (LNAPLs) such as petrol and heating oil, DNAPLs have the ability to migrate to significant depths below the water table where they slowly dissolve into flowing groundwater, giving rise to aqueous phase plumes. A release of DNAPL at the ground surface can therefore lead to long-term contamination of both the unsaturated and saturated zones at a site.

This bulletin provides a summary of an Environment Agency (EA) report entitled, "An illustrated handbook of DNAPL transport and fate in the subsurface". The purpose of the bulletin is to describe how the report came about and to introduce some of the terms, concepts, problems and solutions relating to DNAPL contamination in the UK.

TB 12 - Statistical Assessment of Contaminated Land: Some Implications of the ‘Mean Value Test’ (2006)

Statistical methods are commonly used to guide decision-making in many regulatory contexts. For the assessment of potentially contaminated land, it is common practice to use the ‘Mean Value Test’ approach defined in DEFRA and Environment Agency’s Contaminated Land Report 7.  However, when applied to real environmental datasets, the ‘Mean Value Test’ can actually prove to be a non-conservative choice that may wrongly categorise a potentially contaminated site as ‘clean’.

This bulletin illustrates how such a situation could arise, highlights the implications and introduces alternative appropriate methods to derive the 95% Upper Confidence Limit of the mean soil concentration.

TB 13 - Understanding Soil Washing (2007)

Soil washing is an established technique for dealing with contaminated soil, especially for sandy soils. Soil washing processes vary from the relatively simple involving a few particle separation processes, to those which are more sophisticated and involve many more processes. Laboratory treatability tests are required in order to ascertain likely application and the types of soil washing processes required.

This bulletin describes the principles behind soil washing technology for contaminated materials.

TB 14 - Treatment of Chromium Contamination and Chromium Ore Processing Residue (2007)

Chromium is a transition metal of Group VIB of the Periodic Table which has historically been used in a wide range of industrial applications including steel, pigments, wood preservatives, electroplating, metal finishing, dyes, leather tanning, textiles and chemical manufacture.  In general, the treatment of Cr contamination will focus on the highly toxic hexavalent form of Cr (Cr(VI)), and its transformation into the relatively low toxicity trivalent form (Cr(III)), a process that typically involves chemical reduction and precipitation as Cr(III).

This bulletin provides information on the treatment of Cr contamination in the environment and summarises a number of remedial methods that have been used to treat it. In addition, it looks at the wider issue of chromium ore processing residue (COPR) contamination in the south-east of Glasgow, potential methods for its remediation and the next steps for the redevelopment of this area.