Geochemical properties of aquifers and other geological formations in the UK. Phase 1 : assessment of available data

Milne, C.J.; Kinniburgh, D.G.; Cave, M.R.; Lelliott, M.; Quigley, S.. 2002 Geochemical properties of aquifers and other geological formations in the UK. Phase 1 : assessment of available data. Nottingham, UK, British Geological Survey, 82pp. (CR/02/224N) (Unpublished)

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Abstract/Summary

This report presents an assessment of the possibility of producing a comprehensive reference manual of data for the intrinsic geochemical properties of British aquifers and aquitards. The data which would be included would be for the geochemical parameters of greatest significance for contaminant transport and risk assessment modelling applied to groundwater protection and pollution issues. Current landfill and contaminated land risk assessment models use estimates of cation exchange capacity (CEC) and the fraction of organic carbon (fOC) to describe the chemical attenuation properties of the geological formations. At present, therefore, these two parameters are the most widely used and they form the heart of the proposed Geochemical Properties Manual (GPM). More sophisticated and chemically complex modelling approaches take greater account of the mineralogical characteristics of the formations and therefore carbonate content, clay content, free mineral oxide content, pyrite content and specific surface area are also considered. The amount of bioavailable iron and manganese in a material is increasingly being considered as a controlling influence on the biologically-mediated degradation of pollutants, for example during monitored natural attenuation (MNA) so measurements of this too are included. Consultation with contacts in the environmental regulation, waste management and environmental consultancy sectors showed widespread agreement that a compiled GPM would be of benefit to professionals working in these areas. At present there are no authoritative or extensive compilations of such data, and most studies or investigations have to use either estimates with poor uncertainty associated, or expensive direct site-specific measurements. There is no easy way of reliably selecting data which can be used for rapid screening or emergency response assessments. Review of the extent of existing available data showed that the two abundant and easily accessible sources of relevant data are the BGS corporate data holdings and the collection of Regulation 15 landfill and other risk assessments submitted to the various regions of the Environment Agency. The BGS holdings have been accumulated for a variety of purposes on a range of projects and have not yet been integrated into a single geochemical properties resource. The EA holdings are distributed between the regions and have not been collated. Other data are available in University theses and in consultancy or industry site reports, but again these are distributed and must be individually retrieved. The entire body of data if collated and indexed would provide a foundation for the preparation of a GPM, but the geographical and spatial data coverage would be far from complete. New experimental determinations of primary data for geochemical parameters are desirable to address the most important gaps in the existing data. After review of published methods for determination of the parameters of interest, preferred standard methods have been recommended for most parameters. Further research is needed to establish standard methods for others. Material from the extensive holdings in the BGS core store could be used to provide suitable sample material for many locations without the need for new and expensive field sampling programmes. Statistical and modelling approaches to estimating data for geochemical parameters in the absence of direct measurements are also discussed. Geostatistics, multiple-regression analysis, and process-based mechanistic models, along with the use of proxy experimental measurements such as near-infra-red spectroscopy, are all considered as possible methods of improving data coverage. None is yet sufficiently established to be used without further investigation and validation. Recommendations are given for a second phase of the project, with the objectives of establishing the core of a working GPM and beginning a programme of new experimental determinations. Even a substantial experimental programme will not provide comprehensive data coverage within realistic budgetary and time limits, so the programme must be focussed. Early work should concentrate on providing reliable data and useful coverage for CEC and fOC used in the existing models. Finally some areas are suggested for further research work which are beyond the immediate scope of the GPM project, but which would be of significant benefit in the medium to longer term.

Item Type:	Publication - Report
Programmes:	BGS Programmes > Other
Funders/Sponsors:	British Geological Survey, Environment Agency
Additional Information. Not used in RCUK Gateway to Research.:	This item has been internally reviewed, but not externally peer-reviewed.
Date made live:	02 Oct 2024 11:04 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/538149

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