Environmental Geology & Geotechnical Consultants Ltd

CONTAMINATED LAND SERVICES

Phase 1 Contaminated Land Risk Assessment: from £799 inc. VAT

A Phase 1 Contaminated Land Risk Assessment establishes previous uses of a site and its immediate surroundings. It identifies potential contaminant sources, either historical or current, as well as potential contamination pathways and receptors.

Based on the findings of a desktop study and site walkover, any Potential Pollutant Linkages, in which sources, pathways and receptors all potentially exist, the Phase I Contaminated Land Risk Assessment, characterises these in terms of an initial Conceptual Site Model. This informs the need for work such as intrusive investigation and further risk assessment (Phase 2 Intrusive Investigation). As a rule of thumb, if your site has had any past industrial use, it is likely to require some ground investigation.

A Phase 1 Contaminated Land Risk Assessment, including site walkover survey, costs £799 plus travel expenses.

The Phase I Risk Assessment may be combined with a Phase I Geotechnical Desk Study for a full Phase 1 Geo-Environmental Assessment.

Phase 2 (Intrusive) Contaminated Land Risk Assessment

Seeking to reject or confirm potential Source – Pathway – Receptor pollutant linkages identified at Phase I and to refine the preliminary Conceptual Site Model, intrusive investigations as part of a Phase II  are undertaken to identify and target areas likely to be contaminated by historical site use (e.g. oil tanks, furnaces etc).

Investigation is carried out in accordance with CLR11 and relevant British Standards. It will be conducted in consultation with the local planning authority’s Environmental Health or Contaminated Land Officer, and with the Environment Agency.

Intrusive investigation into a site involves, for example, hand- or machine-dug trial pits, window samples or boreholes, and soil and surface/groundwater sampling. Site investigation for a Phase 2 Contaminated Land Risk Assessment may be combined with any required elements of a Geotechnical Site Investigation to maximise the amount of information obtained.

Phase II investigations will include Generic Quantitative Risk Assessment (GQRA) and, where necessary, Detailed Quantitative Risk Assessment (DQRA), which includes analytical contaminant transport modelling (using spreadsheet models). Where required, this can be extended to numerical contaminant transport modelling.

In all cases, the most cost-effective solution for risk mitigation is sought, as per our Professional Code of Conduct.

Phase III – Site Remediation

Phase III involves the identification of the most suitable options for remediating the site, through a REMEDIAL OPTIONS APPRAISAL for each individual Source-Pathway-Receptor linkage identified, followed by production of a REMEDIATION STRATEGY which combines the best options for targeting all Source-Pathway-Linkages identified across a contaminated site as well as measures to control nuisance (noise, dust etc), details of necessary consents and licences, and proposed remediation standards.

A Statement of Remediation Strategy will be produced in consultation with the Environment Agency (EA) and Local Planning Authority (LPA), and will also include a contingency plan in case unexpected contamination is encountered during the work. Remedial targets are clearly stated, as is a verification methodology once works are complete.

Regulator Liaison

EGG Consultants Ltd. undertake regulatory and compliance work relating to all aspects of site investigation, hydrogeology, soils and contaminated land. Our staff have a good working relationship with the Environment Agency and other regulators and work hard to ensure that clients’ projects comply with conditions and requirements set by the regulators.

Expert Witness & Environmental Forensic Services

A number of our Associates are available to act as Expert Witnesses and to conduct Environmental Forensic Services. We have a variety of experience working with solicitors, barristers and judges and are familiar with court proceedings and legal cases. Please CONTACT US with any specific queries.

Monitored Natural Attenuation

EGG Consultants Ltd. will always examine the possibility that the risks associated with a contaminated site may be addressed through Monitored Natural Attenuation (MNA).

Many contaminated sites have shown that natural processes within soils and groundwater are sufficient, over time, to reduce contamination without need for additional intervention. Furthermore, many contaminant plumes in groundwater stabilise at dynamic equilibrium, as contaminant degradation/sorption/volatilisation over the length of the plume works at a rate equivalent to which the contaminant enters the groundwater. This has been particularly well characterised for contaminant plumes generated by landfills, and it is possible that the regulator will accept a robust monitoring stategy to maintain watch that known contamination does not spread, in place of more active intervention.

Monitored Natural Attenuation is therefore often one of the most cost-effective methods of managing the risks associated with land contamination. To establish that MNA is a viable strategy of risk reduction at your site normally requires site investigation, sampling and modelling efforts, in consultation with the Local Planning Authority and the Environment Agency.

You can learn more about Monitored Natural Attenuation here.