Contaminated Site Surveys
Preliminary Risk Assessment
The company has extensive experience of undertaking Preliminary Risk Assessments (commonly still referred to as Phase 1 investigations or desk studies) for land contamination investigation.
These Preliminary Risk Assessments utilise high-quality site-centred Ordnance Survey historical mapping from the late nineteenth century to the present day; comprehensive environmental database searches; and where relevant site walkover surveys. This study determines if the site and surrounding area could have been subject to potentially contaminative use (thus creating potential liabilities) and gives information on other aspects such as radon, watercourses, aquifers and public water supply abstractions.
This phase can also include coal mining searches, petroleum tank searches, liaison with the local authority, basic planning history searches and other searches such as chalk cavities and mining.
The data is then drawn together to assess potential sources, pathways and receptors, culminating in a preliminary conceptual model and risk assessment that and comment on the risk of potentially complete contaminant linkages.
Intrusive Site Investigations
Based upon our understanding of why a client requires investigation work, our engineering consultancy staff will then design a site investigation to meet their objectives. This may be to support the discharge of a planning application; discharging a duty of care where no regulatory body is involved; or assessing environmental liabilities associated with land assets.
Environmental site investigation often utilises the low-disturbance technique of dynamic sampling, as well as excavator-dug trial pits and cable percussion boreholes. Standpipes are often installed for the monitoring and sampling of groundwater and soil gases by our site technicians.
On site monitoring can also include in-situ monitoring for water quality, as well as volatile vapours (e.g. petroleum hydrocarbons). We have in-house UKAS and MCerts accredited laboratory testing capabilities for most contaminants in soil and water.
Structural Soils have investigated sites with varied historical uses including petrol stations, factories, abattoirs, landfills, timber treatment works, scrap yards, gas works and foundries. The proposed developments are again varied, with the most sensitive land use generally being for residential requirements.
Following completion of the desk based and intrusive works, we provide clients with interpretive reports that typically assess and advise on the long term risks to human health; controlled waters; buried concrete and services. Such work involves an updated conceptual model and risk assessment based on the findings of the investigative work. If significant risks to human health or water resources are identified, we can then advise on and complete Detailed Quantitative Risk Assessments (DQRA).
Our interpretive reports can also give guidance on the classification of soils for off-site disposal (including Initial Waste Characterisation and Waste Acceptance Criteria (WAC) tests), as well as any geotechnical aspects such as foundation and retaining wall design.
Remediation & Validation Work
We have extensive consultancy experience in supporting the redevelopment of brownfield land and the assessment of risk to human health and groundwater. Throughout the development stage we can design then assist with the supervision and validation/verification of the remediation process, including the required reporting.
Routinely, liaison is undertaken with local authorities, the Environment Agency (EA) and the National House-Building Council (NHBC) during investigation and remediation. Qualitative and quantitative risk assessments can be undertaken to ensure that remediation projects address all the issues that may give cause for concern.