Geo-Environmental Assessment Reports

Contaminated land contains substances that are hazardous to human health and / or the environment and Geo-Environmental Assessments are typically used to identify, assess and evaluate the level of risk and to determine whether remediation strategies are required.

Regulatory bodies apply the “source-pathway-receptor” linkage when assessing the risk from a potentially contaminated site. The site is considered contaminated if:

  • It contains a sufficient level of a pollutant – the source.
  • This pollutant can get to and affect someone or something – the pathway.
  • Someone or something could be affected by the pollutant – the receptor.

The Geo-Environmental Assessment is often carried out as a phased approach, with the remediation and validation carried out at a later stage.

Phase 1 – Desk Study Report

The desk study involves collating and reviewing historical O.S maps, geological, hydrogeological and environmental data for the site and helps to identify potential environmental, geotechnical and ground engineering hazards at an early stage. If constraints are identified as part of the desk study assessment a preliminary conceptual model is produced that identifies potential on-site and off-site sources of contamination. The data within the Phase 1 Desk Study Report enables a robust Phase 2 intrusive investigation to be designed and undertaken.

Phase 2 – Site Investigation

An intrusive investigation that is designed to provide sampling points across the whole site either at specific positions that have been identified as sources of contamination in the Phase 1 assessment, or in a non-targeted way to achieve ‘random’ sampling. This can include near surface soil samples, trial pits, boreholes, gas and groundwater monitoring. Laboratory testing of the recovered samples is undertaken followed by an initial generic  risk assessment (or detailed risk assessment if required). The purpose of the investigation is to identify the presence of any unacceptable risks to future end users of the site and the environment.

Phase 3 – Remediation Strategy

If unacceptable contamination risks are identified in the site investigation, then a remediation strategy will be required for the site. This involves deriving site remediation criteria for the contaminants that have been recorded at elevated concentrations  to ensure that it is safe for the proposed end use. Proposals may include on-site treatment, localised removal of contamination ‘hot-spots’  or importation of a soil capping layer.

Phase 4 – Validation

On completion of the any site specific remediation, a validation report is required to ensure that the remedial concentrations set in the remediation strategy have been achieved.

Nicholls Colton Group has been providing contaminated land advice to its clients for over 50 years, with its experienced geo-environmental engineers and geologists able to oversee the geo-environmental assessment from pre-start to final completion.