Contaminated Land Assessment: A Complete Guide for Developers and Landowners
At Clear Environmental, we make navigating contaminated land risks simple, clear, and commercially focused. Whether you are developing a brownfield site, investing in land, or fulfilling planning conditions, understanding the contaminated land assessment process is critical to unlocking your site's full potential.
This guide walks you through the entire process — from initial risk screening to final remediation — with expert insights drawn from industry best practices and Clear Environmental’s experience across South East England.
What is a Contaminated Land Assessment?
A contaminated land assessment evaluates whether land poses risks to human health, property, or the environment. It identifies potential liabilities early, helping you manage costs, reduce delays, and satisfy planning or lender requirements.
Contaminated land can arise from historic industrial use, waste disposal, chemical storage, or even agricultural activities.
Key reasons for commissioning a land assessment:
- Satisfying planning conditions.
- Supporting land purchase due diligence.
- Informing redevelopment design and costs.
- Meeting environmental legal obligations.
The Contaminated Land Assessment Process
At Clear Environmental, we follow a clear, phased approach aligned with Environment Agency Land Contamination Risk Management (LCRM) guidance:
Phase 1: Preliminary Risk Assessment (Desk Study)
What it involves:
- Desk-based research into site history, geology, hydrology, and environmental records.
- Site walkover to identify visible risks.
- Development of an initial Conceptual Site Model (CSM).
- Identification of pollutant linkages.
Purpose:
- To determine whether there is a potential risk that warrants further investigation.
Key Outputs:
- Phase 1 Desk Study Report.
- Risk screening conclusions.
- Recommendations for Phase 2 investigation (if needed).
Typical Timeframe: 10 Days - can be faster where feasible.
To learn more about Phase 1 Desk Studies (Preliminary Risk Assessments) is click here.
Phase 2: Site Investigation (Intrusive Investigation)
What it involves:
- Soil, groundwater, surface water, and gas monitoring.
- Laboratory testing for key contaminants.
- Refinement of the Conceptual Site Model.
Purpose:
- To collect site-specific data and confirm whether actual contamination exists and its extent.
Key Outputs:
- Phase 2 Ground Investigation Report.
- Risk assessment based on UK regulations.
- Remediation recommendations (if necessary).
Typical timeframe: 4–6 weeks (depending on site complexity)
To learn more about Phase 2 Site Investigations (Intrusive Investigations) is click here.
Remediation and Verification (if required)
What it involves:
- Design and implementation of a remediation strategy.
- Monitoring and validation testing.
- Final verification reporting to regulators.
Purpose:
- To ensure any contamination risks are appropriately managed and the site is fit for its intended use.
Typical timeframe: Varies depending on remediation scale.
Key Contaminants We Commonly Encounter
- Heavy Metals (Lead, Arsenic, Cadmium)
- Hydrocarbons (TPH, PAHs)
- Asbestos (in soil)
- Volatile Organic Compounds (VOCs)
- PFAS (emerging contaminant of concern)
Understanding the site-specific risks early helps avoid costly surprises later.
Why Choose Clear Environmental?
- Clear, Pragmatic Advice: We focus on what matters commercially and technically — no unnecessary complications.
- Speed and Responsiveness: We move at the speed of your project to avoid delays.
- Regional Expertise: We understand the unique geological, environmental, and planning contexts of South East England.
When a Phase 1 Desk Study identifies potential environmental risks, the next step is a Phase 2 Site Investigation — also called an intrusive investigation. This critical stage gathers real-world data to confirm or rule out contamination, protecting your project from unforeseen costs, planning delays, or environmental liabilities.
In this guide, we break down:
- How Phase 2 builds on Phase 1.
- The different investigation techniques (and when to use each).
- Typical timescales.
- How laboratory testing refines the site’s risk profile.
- What to expect at the end of a Phase 2 investigation.
How Phase 2 Builds on Phase 1
While a Phase 1 is based on desk research and a site walkover, a Phase 2 collects physical evidence through soil, groundwater, and ground gas sampling.
In short:
Phase 1 = Identify Potential Risks.
Phase 2 = Confirm or Dismiss Risks with Hard Data.
The findings from Phase 2 enable:
- Quantitative Risk Assessments (QRA) based on actual contamination levels.
- Decisions about whether remediation is necessary.
- Planning condition discharge if no unacceptable risks are found.
Phase 2 Site Investigation Methods
Different methods are used depending on the site, the anticipated risks, and the required depth of investigation:
- Best For: Shallow contamination, made ground assessment, visual soil profiling, locating foundations.
- Typical Depths: Up to 4 metres.
- Equipment: Mechanical excavator or hand-dug.
- Best For: Shallow contamination, installation of ground gas and groundwater wells, restricted access sites, cost-effective sampling.
- Typical Depths: Generally 5–6 metres, but can extend up to 10 metres depending on ground conditions.
- Equipment: Window sampling rig (tracked or towed).
- Best For: Deeper soils, groundwater sampling, ground gas monitoring, and collecting geotechnical data.
- Typical Depths: Up to 30 metres or more.
- Equipment: Cable percussion drilling rig.
- Best For: Hard ground, bedrock investigations, and installation of deep groundwater wells.
- Typical Depths: Up to 100 metres or more.
- Equipment: Rotary drilling rig (open hole, cored, or augered).
Tip: On smaller development sites, a combination of trial pits and window sampling often provides excellent coverage at a cost-effective price.
Types of Laboratory Testing During Phase 2
After sampling, the materials collected are sent for laboratory analysis to determine contamination levels:
- Soil Testing:
- Heavy metals (e.g., lead, arsenic)
- Hydrocarbons (TPH, PAHs)
- Asbestos in soil
- Emerging contaminants (e.g., PFAS)
- Groundwater Testing:
- Soluble contaminants (e.g., hydrocarbons, BTEX, solvents)
- Metals in solution
- PFAS detection
- Ground Gas Monitoring:
- Methane, carbon dioxide, oxygen concentrations
- Flow rates (for CS classification)
The results are then compared against appropriate assessment criteria (e.g., GACs/SACs) to determine whether remediation is needed.
What Happens After Phase 2 Sampling?
1. Data Analysis and Quantitative Risk Assessment (QRA):
Risk to human health, controlled waters, or property assessed.
2. Conceptual Site Model Update:
Confirmed pollutant linkages mapped and risk-ranked.
3. Decision Point:
No significant risks: Reporting and planning condition discharge.
Significant risks: Recommend remediation (Phase 3).
Phase 1 vs Phase 2 - Quick Comparison Table
FAQs About Phase 2 Site Investigations
What happens if contamination is found in a Phase 2?
If contaminants exceed safe levels, a Remediation Strategy (Phase 3) will be needed to outline how risks will be managed.
Can a Phase 2 rule out the need for remediation?
Yes — many sites require no further action after a properly scoped Phase 2 investigation.
Is ground gas monitoring always required?
Not always. It depends on the site's history, geology, and desk study findings.
Conclusion: Why a Clear Phase 2 Strategy Matters
A well-designed Phase 2 Site Investigation provides confidence, clarity, and control.
It ensures you're fully informed about site risks, avoids unnecessary remediation, and moves your project efficiently through planning.
At Clear Environmental, we tailor Phase 2 investigations to your site — no over-scoping, no hidden costs, just clear advice.
What is a Phase 1 Desk Study (Preliminary Risk Assessment)?
Whether you're planning to develop land, submit a planning application, or purchase a brownfield site, understanding environmental risks early is essential.
A Phase 1 Desk Study — also called a Preliminary Risk Assessment — is the first critical step in managing those risks efficiently, helping avoid costly surprises later in your project.
This guide explains exactly what a Phase 1 involves, why it’s required, and what you can expect from the process.
What is a Phase 1 Desk Study?
A Phase 1 Desk Study is a preliminary environmental assessment that evaluates the potential for land contamination based on historical and current land uses.
It is called a “desk study” because it mainly relies on reviewing existing records and data sources, alongside a site visit.
It does not involve any intrusive ground investigation — that's reserved for Phase 2 if risks are identified.
In simple terms:
A Phase 1 identifies if there’s a potential problem — before you commit to site purchase, design, or construction.
Why is a Phase 1 Desk Study Needed?
A Phase 1 is often required to:
- Support planning applications (especially brownfield or previously developed sites).
- Satisfy lender due diligence for property transactions.
- Manage liability and avoid unexpected abnormal costs.
- Confirm if further investigations (Phase 2) are needed.
Without a Phase 1, local authorities, insurers, and funders may refuse to progress development or financing.
Key Components of a Phase 1 Desk Study
A thorough Phase 1 typically includes:
What Does a Phase 1 Report Contain?
A typical Phase 1 Desk Study Report will include:
- Executive Summary (key findings and recommendations).
- Site location and description.
- Historical land use review (maps and aerial photography).
- Environmental setting (geology, hydrology, groundwater).
- Regulatory database review (permits, enforcement notices, pollution incidents).
- Walkover survey findings (including annotated site photos).
- Preliminary Conceptual Site Model (CSM).
- Risk assessment and clear conclusions.
- Next steps, if further investigation is needed.
At Clear Environmental, our Phase 1 reports are concise, commercially-focused, and designed to satisfy planning authorities and lenders without unnecessary complexity.
How Long Does a Phase 1 Desk Study Take?
Most Phase 1 assessments can be completed within 10 Days.
We also offer fast-track services if you’re working to tight planning or transaction deadlines.
Phase 1 Desk Study vs. Environmental Search: What's the Difference?
Key point: An Environmental Search is not a substitute for a Phase 1 — it’s simply a basic desktop screening.
FAQs About Phase 1 Desk Studies
Q1: When should I commission a Phase 1?
Ideally before site acquisition or at the earliest planning stage, so risks and costs are identified early.
Q2: Will a Phase 1 always recommend a Phase 2?
No — many sites with clean histories and no risk linkages can be signed off at Phase 1.
Q3: Who needs a Phase 1 Desk Study?
Developers, property investors, planners, architects, solicitors, and lenders commonly require Phase 1 studies.
Q4: Will the council accept my Phase 1 report for planning?
Yes — provided it follows UK guidance (such as EA Land Contamination Risk Management (LCRM)) and is prepared by qualified specialists.
Q5: What happens if my Phase 1 shows contamination risks?
We’ll outline the recommended Phase 2 site investigation scope and cost early, so you remain in control.
Why Clear Environmental for Your Phase 1?
A Phase 1 Desk Study isn’t just a box-ticking exercise — it’s your first opportunity to manage risks, reduce abnormal development costs, and protect your investment.
At Clear Environmental, we combine technical expertise with commercial insight to deliver Phase 1 Reports that meet planning, legal, and financial requirements — quickly and clearly.
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