Contaminated Land Appraisals are undertaken both as part of an overall Geotechnical and Environmental Site Assessment but also, specifically, to check on the contaminated land potential of a site or to provide data to satisfy Planning Conditions imposed by the Local Authority. A Phase I Desk Study is initially undertaken to permit the development of a Conceptual Site Model (CSM) and this is then investigated as dictated by the site condition and pollutant linkages identified. The results of the work are then risk assessed and pollutant linkages confirmed, or otherwise. The presence of pollutant linkages dictates whether remedial actions are required.
CASE STUDY
A former sand quarry site, now a landfill, near Gloucester was being progressively developed as a business park. Applied Geology was approached to advise a developer on a specific site within the park. It was clear at a very early stage that there was an abundance of data on the site comprising three different investigations from the initial concept of the business park through to specific adjacent developments and it was therefore agreed with the Local Authority that all of the existing data would be appraised and a Conceptual Model drawn up. The Conceptual Model allowed the pollutant linkages to be established and a further phase of investigation was undertaken, all with the agreement of the Local Authority. This work subsequently identified that the landfill was ‘gassing’ and the results of the detailed monitoring undertaken was utilised to design a gas control system in conjunction with another geotechnical firm. Theoretical risks (pollutant linkages) were also deemed to exist to both the end users of the site and a local water course and a minor aquifer – the sand that had originally been quarried to create the landfill. The former risk was mitigated by the introduction of a simple cover layer (clay overlain by granular material) and a subsequent P20 Groundwater Risk Assessment adequately determined that the risk to the water course and aquifer was minimal providing a certain pavement construction was utilised. The remediation of the site was agreed with both the Local Authority and the Environment Agency and subsequently successfully undertaken and validated by Applied Geology.
The basics of this investigation and remediation, were taken into an adjacent and much larger, second phase of development for the same client.
