Phase 1 Contaminated Land Desk Study

Contaminated land refers to any land that has been polluted with substances that can harm human health or the environment. This can include industrial sites, brownfield sites, and areas where hazardous waste has been disposed of. The Environment Agency, local planning authority, and local authorities are responsible for identifying and managing contaminated land. A preliminary risk assessment is typically conducted to determine the level of risk posed by the contamination. This assessment is usually carried out by a geo-environmental consultant and involves a desk study, site walkover, and analysis of environmental data. Due diligence is crucial in conducting a Phase 1 Preliminary Risk Assessment to ensure all relevant risks are considered before proceeding with development planning.

 

 

 

A Phase I Desk Study, also known as a Preliminary Risk Assessment, Desktop Survey and Phase I Land Contamination Assessment, among others, includes a review of all accessible sources of information, detailed information required, such as site plans, photographs, maps (current and historical), environmental data records, local authority records, petroleum officer records, mining records and any previous site investigation reports. Such information may be available electronically from various online sources, or as hard copies from the current or former site owners and occupiers, the local council, libraries, public record offices or even local history groups.

​

A qualitative assessment plays a crucial role in evaluating risks associated with potential harm or pollution on sites during preliminary assessments. Understanding ground conditions is essential in evaluating potential land contamination risks and the environmental status of a site.

​

The desktop review should be combined with a site walkover survey undertaken by an experienced geo-environmental engineer, to identify any significant site features, particularly those which may represent potential contamination sources, such as tanks (above and below ground), chemical storage areas, industrial process areas, evidence of waste disposal, areas of stressed vegetation, unusual landforms etc. Furthermore, the opportunity to speak with site personnel or anyone else with knowledge of past and current site operations can be an invaluable source of anecdotal evidence for site activities that would not otherwise be recorded (such as undocumented waste disposal). Together, the findings of the desktop review and the site walkover are used to establish the following:

• Geology and Hydrogeology

• Hydrology / Flooding

• Environmental Sensitivity

• Mining susceptibility

• Potential Contamination Sources

• Environmental Setting

​

Assessing ground gases is also important as part of both detailed and exploratory site investigations.

​

Having established the above, a Conceptual Site Model (CSM) is developed, which is a visualisation or descriptive representation of the site setting which highlights the source-pathway-receptor pollutant linkages that may be present on a site in its current state, or that may be created based on future development proposals. The CSM is an essential component of the Preliminary Risk Assessment, the purpose of which is to determine the likelihood of any of the potential pollutant linkages being present and significant, and therefore whether any further works (a Phase II Site investigation) are required. If unacceptable risks are detected, further investigations may be necessary to ensure the site can be developed safely. The Preliminary Risk Assessment is the primary output of the Phase I Desk Study report.

​

An intrusive investigation may be required when information from earlier assessments is insufficient to address potential contaminant risks. This process is crucial to refine conceptual site models and confirm contaminant linkages. Detailed information gathered through site investigations is essential to support the assessment of potential contaminant linkages and ensure regulatory compliance in the Phase 1 Desk Study report.​

​

​

​

A desk study is a crucial step in the contaminated land assessment process. Identifying potential issues at an early stage is important as it allows for informed decision-making regarding environmental hazards. It provides a comprehensive assessment of the potential risks associated with a site and helps to identify potential sources of contamination. The benefits of a desk study include reducing the risk of unforeseen costs and liabilities, identifying potential safety issues, and providing valuable information for planning applications.

​

A desk study can also help to identify potential pollutant linkages and inform the need for further investigation and assessment. By conducting a desk study, developers and property owners can ensure that they are aware of any potential contamination issues and can take steps to mitigate them.

​

​

​

​​A robust Phase I Desk Study is the minimum requirement of contaminated land planning conditions and planning approval, and an essential foundation for any subsequent stages of contaminated land investigation, the design of which will be informed by the CSM developed as part of the Phase I. An intrusive site investigation often follows the desk study to gather detailed, often complex information about contamination risks.

​

In some cases, a thorough desk study may demonstrate that no potentially significant pollutant linkages are present and that no further investigation works are required. A high-quality desk study will ensure only the necessary ground investigation works are undertaken, and that any potential liabilities are identified, thus resulting in potentially substantial cost savings.

​

Additionally, building control plays a crucial role in ensuring that reports meet the requirements of local planning authorities and other stakeholders, emphasising the importance of producing compliant and accepted Phase 1 desk study reports.​

​

​

​

G&J have many years of experience undertaking Phase I Desk Studies for sites of all sizes, development projects, from individual plots to former industrial sites covering several hectares, in locations throughout the Midlands and across the UK. We can also combine the walkover survey with a basic exploratory investigation (sampling and analysis of near-surface soils), which can be a cost-effective way of satisfying planning conditions on sites that are low risk, but for which a Phase I Desk Study alone may not be sufficient. This is crucial for safeguarding land meant for future use, proposed development, and ensuring safe land development.

​

Costs:

The cost of most of our Phase I Desk Studies, including a walkover survey, is £895* plus VAT. On some very straightforward sites, we may be able to undertake a desk study without a walkover survey, for which the cost is £695 plus VAT

​

*Costs may be higher for larger, more complex sites.

​

​

​

A Conceptual Site Model (CSM) is a crucial component of a Phase 1 Preliminary Risk Assessment. It is a written or diagrammatic representation of the site’s characteristics, including the potential sources of contamination, pathways, and receptors. The CSM is used to identify potential contaminant linkages and assess the risks associated with each linkage. Developed based on the information gathered during the desk study and site walkover, the CSM is refined and updated as more information becomes available.

​

This model is an essential tool for communicating the site’s risks to stakeholders and for informing further investigation and remediation efforts. In the context of the National Planning Policy Framework (NPPF) and the National House-Building Council (NHBC) guidelines, a CSM is a critical component of a comprehensive assessment of a site’s environmental risks.

​

​

​

A Site Walkover, also known as a site reconnaissance, is a visual inspection of the site to gather information about its condition and potential sources of contamination. Conducted by a geo-environmental consultant, the walkover involves observing the site’s features, such as its topography, geology, and vegetation. The consultant will also look for signs of potential contamination, such as fuel tanks, industrial activities, or other pollution incidents. The information gathered during the site walkover is used to refine the Conceptual Site Model and to identify areas that may require further investigation. The site walkover is an essential component of a Phase 1 Preliminary Risk Assessment and is often required by local authorities as part of the planning process.

​

​

​

Data collection and analysis are critical components of a Phase 1 Preliminary Risk Assessment. The data collected during the desk study and site walkover are analysed to identify potential contaminant linkages and to assess the risks associated with each linkage. This analysis involves reviewing historical records, such as past uses of the site, and evaluating the potential for contamination based on the site’s environmental setting. Additionally, the data analysis assesses the potential risks to human health and the environment, including the risks associated with ground gases, controlled waters, and other pollution incidents. The results of the data analysis are used to refine the Conceptual Site Model and to inform further investigation and remediation efforts.

​

​

​

The Phase 1 process involves a preliminary risk assessment, which is typically conducted by a geo-environmental consultant. This assessment involves a desk study, site walkover, and analysis of environmental data, relevant information to identify potential sources of contamination and assess the risk posed to human health and the environment. The Phase 1 process is usually carried out following the National Planning Policy Framework and involves consultation with local authorities and the Environment Agency. The output of the Phase 1 process is a comprehensive report that provides a detailed assessment of the potential risks associated with the site and recommends further action if necessary. For further information on sustainability practices and data collection for risk assessment, please refer to the additional resources provided.

​

​

​

A Site Investigation is a detailed examination of the site to gather more information about its condition and potential sources of contamination. This investigation may involve intrusive techniques, such as drilling or excavating, to collect soil or groundwater samples. These samples are then analysed to determine the presence and extent of contamination. Typically conducted in phases, each phase of the investigation builds on the information gathered during the previous phase. The investigation is designed to provide a comprehensive assessment of the site’s environmental risks and to inform remediation efforts. In the context of the Environment Agency’s guidelines, a site investigation is an essential component of a detailed risk assessment, and it is often required by local authorities as part of the planning process.

​

​

​

The regulatory framework for contaminated land is set out in the National Planning Policy Framework and the Environmental Protection Act 1990, including pollution control. The framework requires that contaminated land be identified and managed to prevent harm to human health and the environment. Local authorities and the Environment Agency are responsible for enforcing the regulatory framework and ensuring that contaminated land is managed per the regulations.

​

The framework also requires that developers and property owners conduct preliminary risk assessments and provide comprehensive reports to support planning applications. The regulatory framework is designed to ensure that contaminated land is managed in a way that protects human health and the environment, while also supporting sustainable development and regeneration. It is crucial to evaluate the impact on the wider environment during the assessment process.

​

Ready to ensure your site is safe and compliant? Contact G&J Geo-Environmental today to schedule your Phase 1 Desk Study and Preliminary Risk Assessment. Our experienced team of geo-environmental consultants is here to guide you through the planning process, ensuring all potential risks are identified and managed effectively. Visit our website or call us now to learn more about how we can support your development project with comprehensive contaminated land assessments.