Knowledge of the natural baseline quality of groundwaters is an essential prerequisite for understanding pollution and for imposing regulatory limits. The natural baseline of groundwaters may show a range of concentrations depending on aquifer mineralogy, facies changes, flow paths and residence time. The geochemical controls on natural concentrations are discussed and an approach to defining baseline concentrations using geochemical and statistical tools is proposed. The approach is illustrated using a flowline from the Chalk aquifer in Berkshire, UK where aerobic and anaerobic sections of the aquifer are separately considered. The baseline concentrations for some elements are close to atmospheric values whereas others evolve through time-dependent water-rock interaction. Certain solutes (K, NH(4)(+)), often considered contaminants, reach naturally high concentrations due to geochemical controls; transition metal concentrations are generally low, although their concentrations may be modified by redox controls. It is recommended that the baseline approach be incorporated into future management strategies, notably monitoring.

This case study describes pollution of the Lincolnshire Limestone aquifer, predominantly by the herbicide Mecoprop, to the north of Peterborough, Cambridgeshire. Key features of the case study are the occurrence of a series of former landfill sites located on the Lincolnshire Limestone aquifer outcrop, a nearby groundwater abstraction for public supply within the confined aquifer and the presence of a major geological fault and its associated control on groundwater movement. At the time of licensing, the fault was considered to hydraulically isolate the landfill sites from the abstraction. A multiphase investigation, begun in 1990, was conducted by the National Rivers Authority and involved close liaison with the Cambridgeshire County Council, landowners, site operators and the Anglian Water Company. Investigations have focused on identifying and proving the source of pollution and determining its severity and extent. Remedial strategies and the implications of future change in hydraulic conditions have also been considered. A medium-term risk management strategy for the area has been devised. This is in line with the UK Government’s principles for contaminated land management.

Borehole log data gathered during a subsidence investigation in 1978-79 are used to derive a classification scheme for Coal Measure rocks. The results of height of void migration above workings are compared to those arising from use of Piggott & Eynon's (1977) geometrical collapse zone method and Bienawski's (1980) Rock Mass Rating scheme. It is concluded that the analysis helps to assess areas of greatest instability, which thus aids land-use planning and also the planning of ground investigations, ground stabilization, and re-development.

The geological environment of two South Wales collieries at which site investigations were carried out is summarised. This is followed by a review of identified geological parameters and their effects on floor heave under the headings of discontinuities, mineralogy, and groundwater. Methods of underground site investigation, laboratory testing, and data treatment are summarised. The effect of an increase of groundwater content on mechanical parameter values was quantified for laboratory tested rock cores, and in situ interbedded strata sections. The extent to which groundwater affects floor heave was found to be controlled by the mineralogical and structural nature of the floor strata.

Powers available to the NRA are summarized. Definitions of waste and groundwater are given. The scale of the problem is described by reference to the legacies of historical 'dilute and attenuate' landfills, mainly occupying disused surface mineral excavations.An explanation is given of an interpretation of the National Rivers Authority Policy and Practice for the Protection of Groundwater in context of waste disposal. Special emphasis is placed on the protection of groundwaters by development control. Reference is made to work regarding best practice for containment and management of leachates generated at landfills.Scenarios are described which are then used to assess the likely impact of the policy on the future of waste disposal.It is concluded that the NRA's policy provides a framework which is being used to promote the practical protection of vital natural groundwater resources.