Understanding Contaminated Land
Understanding Contaminated Land
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- Land Contamination
This is a wide ranging term used to describe the impact to soil and water from historical human activity. Land contamination is caused by a variety of past uses including historical industrial use, disposal of waste materials (licenced and unlicensed) and the importation of material to raise ground levels. In some cases, contamination of soils can occur due to natural occurring compounds, typically metals.
- Contaminated Land
In some cases, where there is considered to be a possibility that harm could be caused to certain water bodies, human health and ecology, land impacted by contamination can be determined as ‘Contaminated land’. This has a specific legal definition set out in Part IIA of the Environmental Protection Act.
Known as the model procedures for the Management of Land Contamination, CLR 11 sets outs the guiding principles and processes for the assessment and remediation of land contamination. The document is designed to ensure all environmental assessments are undertaken in accordance with government policies and / or legislation within the UK.
- Land Contamination / Environmental Assessment
The process of investigating, assessing and remediating land contamination. The works are designed assess and address risks to:
- Human health.
- Property (existing or proposed) including buildings, crops, livestock, pets, woodland and service lines and pipes.
- Adjoining land.
- Groundwaters and surface waters.
- Ecological systems.
- Archaeological sites and ancient monuments.
- Phase 1 Environmental Assessment
Term often used to describe the first phase of assessment of land contamination. Typically, this involves a desk study, site inspection / walkover and completion of a preliminary risk assessment.
- Desk Study
An assessment of the potential for contamination to be present on site from a review of available information, typically including historical maps, regulatory data, geology, groundwater and ordnance survey mapping, petroleum officer information and planning records. This is similar to a Phase 1 Environmental Assessment but doesn’t include a site inspection / walkover. This information is used to derive a preliminary risk assessment.
- Site Inspection / Site Walkover
Site visit to provide a detailed description and identify sources pathways and receptors on a site and in the surrounding area. This is often undertaken as part of a Phase 1 Environmental Assessment. Preliminary Risk Assessment but can also be completed as a standalone piece of work to enable an assessment of environmental risk management or environmental compliance.
- Phase 2 Environmental Assessment
Term often used to describe the second phase of assessment of land contamination, typically a site investigation. This involves the assessment of ground conditions and the collection of soil, groundwater and surface water samples for chemical analysis to confirm levels of contamination and allow an updated assessment of risks to receptors.
- Site Investigation
Method of assessing ground conditions and collection of soil, groundwater and surface water samples. This typically includes the drilling of boreholes and / or excavation of trial pits.
- Geo-Environmental Assessment
Site investigation designed to assess environmental risks (similar to Phase 2 Environmental Assessment) but typically combined with a geotechnical assessment for foundation and engineering design.
- Geotechnical Assessment / Investigation
Site investigation specifically designed to confirm engineering requirements (foundation design, etc) for proposed developments. This includes information obtained on site and also independent laboratory testing.
- Generic Quantitative Risk Assessment (GQRA)
The method of assessing the significance of chemical analysis results on soil, groundwater and surface water samples against published generic assessment criteria and environmental quality standards.
- Detailed Quantitative Risk Assessment (DQRA)
The method of assessing the risk to human health and / or groundwater and surface water using mathematical models inputted with site specific data and information.
Process of ‘cleaning up’ of land contamination to levels no longer considered to be an unacceptable risk to the identified receptors.
- Remediation Options Appraisal
A method of assessing the most suitable remediation options based upon the contaminants requiring remediation, technical suitability, site specific constraints, the level of remediation needed, sustainability and cost. A mathematical appraisal is often used to identify the most suitable option.
- Remediation Strategy / Remediation Method Statement
A document which sets out the overall strategy for remediation including the aims, detailed specification of the chosen option, confirmation of remediation target levels and details of how the success of the works is to be verified. This is required prior to commencement any remediation works.
- Remediation Trial
This is often undertaken to trial the chosen remediation method to ensure that the theoretical suitability is applicable in site specific conditions. The trial is often a scaled down version of the final chosen method.
- Verification / Validation
Verification is the method of confirming that the remediation has been successful in meeting its aims and objectives. The verification report will include details of the works undertaken, variations to the original scope, comparison of soil and or water sample analysis results against the target levels and details of disposal of waste materials.
- Environmental Risk Management
Process of assessing potential environmental risks at a property including the identification of existing potential liabilities and assessing the potential for future contamination to occur. This processes identifies areas of site improvement ranging from identifying key pollution prevention measures and incident response planning.
- Environmental Due Diligence
Forms an increasingly important part of the corporate due diligence process undertaken prior to the purchase and sale of land and property and as part of mergers and acquisitions of businesses. The process aims to identify environmental liabilities and associated costs in order to protect the proposed purchaser or funding partner from future unforeseen costs or legal action.
- Geo-Environmental Feasibility Assessment
An assessment of the feasibility of a proposed brownfield redevelopment based geotechnical, waste management, earthworks and land contamination restraints. This forms an important part on whether to progress with a particular development or design.
- Waste Classification
The process of testing, analysis and subsequent classification of soils as inert, non-hazardous or hazardous waste in order identify an appropriate disposal route. This is a requirement of landfill or reclamation facilities prior to accepting materials.
- Baseline Assessment / Investigation
Involves a site investigation prior to commencement of operations on a leased site in order to identify baseline levels for comparison against when the lease is surrendered. This ensures that the client is only responsible for remediation to levels of contamination present prior to operations. This process also identifies whether business operations are likely to be disrupted as a result of land contamination and also ways of reducing the potential for contamination to occur during future operations.