The assessment and management of contaminated land is fundamental to sustainable development, environmental protection, and the successful delivery of redevelopment projects. Harrison Group provides a comprehensive contaminated land consultancy service, supporting developers, landowners, design teams and local authorities. We provide advice and assessments, from initial site appraisals, to detailed contaminated land and groundwater risk assessments, through to remediation and verification services.
Our assessments are undertaken in accordance with the Environment Agency’s Land Contamination Risk Management (LCRM) framework, using a risk-based approach, centred on the identification and evaluation of source-pathway-receptor pollutant linkages, and development of a conceptual site model (CSM). The staged approach is as follows:
Stage 1, Tier 1: Preliminary Risk Assessment
The preliminary risk assessment (PRA) comprises a detailed desk-based study and site reconnaissance by trained engineers. Historical maps, environmental records, geological and hydrogeological information, regulatory datasets, and available site information, are reviewed to identify potential contaminant sources, pathways, and receptors.
This stage of assessment culminates in the development of an initial conceptual site model, and provides a qualitative assessment of potential risks to:
- Human health
- Controlled waters
- Property and infrastructure
- Ecological receptors
The findings are used to determine whether intrusive investigation is required, and suggest a suitable scope.
Stage 1, Tier 2: Generic Quantitative Risk Assessment
Where potentially significant pollutant linkages are identified, intrusive site investigations are undertaken to obtain site-specific data. This may include the sampling and testing of soil samples, groundwater, and ground gases, together with geotechnical testing and environmental monitoring.
The results are assessed in comparison to relevant generic assessment criteria, to determine whether unacceptable risks may be present. The conceptual site model is refined, and recommendations are made regarding the need for remediation or further assessment.
Stage 1, Tier 3: Detailed Quantitative Risk Assessment
Where risks cannot be adequately assessed using generic criteria, Harrison Group undertakes a detailed quantitative risk assessment (DQRA) using site-specific data and modelling techniques.
DQRA may include:
- Human health risk assessment
- Controlled waters risk assessment
- Ground gas risk assessment
- Groundwater modelling
- Vapour intrusion assessment
- Remediation target derivation
This approach allows risks to be quantified using realistic site-specific assumptions, often integrating data in our award-winning 3D modelling, providing more sustainable and proportionate development solutions.