Contamination Risk Assessment Consultants for Planning Applications
Planning authorities across England routinely require a Contamination Risk Assessment before granting permission for new development, particularly on brownfield, previously developed, or industrial land. Whether you're converting a former warehouse, building on an old petrol station forecourt, or developing land with an unknown history, we provide Phase 1 desk studies and Phase 2 site investigations that satisfy local authority requirements and keep your application moving.
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We work with developers, architects, planning consultants, and private clients on sites across London and England, from straightforward residential conversions to complex commercial and mixed-use schemes on heavily constrained brownfield land.
What Is a Contamination Risk Assessment?
A Contamination Risk Assessment is a structured evaluation of whether a site poses unacceptable risk to human health, controlled waters, or the wider environment as a result of contamination in the ground. It follows a tiered approach set out in the Environment Agency's Land Contamination Risk Management (LCRM) guidance and BS 10175, and is built around the Source-Pathway-Receptor (SPR) model.
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The assessment typically begins with a Phase 1 Desk Study — a desktop review of historical maps, aerial photography, geological and hydrogeological records, and regulatory databases — to identify potential sources of contamination and establish a Conceptual Site Model. Where the Phase 1 identifies plausible pollutant linkages that cannot be dismissed without intrusive investigation, a Phase 2 Site Investigation follows to characterise contamination and assess risk quantitatively.
When Is a Contamination Risk Assessment Required?
Local planning authorities in England routinely request a contamination risk assessment as a planning condition or pre-condition for applications involving:
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Residential development (including flats, HMOs, and care homes) on land with a potentially contaminative history
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Commercial development on brownfield, infill, or former industrial land
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Change of use from commercial or industrial to residential
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Extensions or basement excavations where ground disturbance is significant
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Development near a former landfill, gasworks, railway corridor, tannery, dry cleaner, or chemical works
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Any site where a previous Phase 1 or site investigation identified contamination risk
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Development within a Source Protection Zone or near a sensitive receptor such as a watercourse
Even sites that appear straightforward can have a contaminated history. In London in particular, centuries of industrial activity mean that brownfield conditions and made ground are the norm rather than the exception. If you are unsure whether your site requires an assessment, we offer a no-obligation preliminary opinion based on desk study data.
Our Contamination Risk Assessment Services Include:
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Phase 1 Desk Study and Preliminary Risk Assessment (PRA)
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Conceptual Site Model development
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Site Walkover
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Quantitative Risk Assessment (QRA) against Generic Assessment Criteria
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Site-specific risk assessment and derivation of site-specific target values
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Remediation Strategy preparation
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Validation and Verification reporting
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Stakeholder liaison with local authority environmental health and planning teams
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Liaison with the Environment Agency on controlled waters risk
Understanding the Source-Pathway-Receptor Model
Every contamination risk assessment is structured around the Source-Pathway-Receptor (SPR) model. A pollutant linkage only exists — and risk only arises — where all three elements are present and connected:
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A source is a substance in or under the ground that could cause harm: petroleum hydrocarbons, heavy metals, asbestos, volatile organic compounds (VOCs), coal tar and PAHs, solvents, or a combination of these.
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A pathway is the mechanism by which a contaminant could reach a receptor — through direct contact with soil, vapour intrusion into a building, leaching into groundwater, or migration via surface water runoff.
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A receptor is whoever or whatever could be harmed: future residents, construction workers, controlled waters, ecological receptors, or building materials and services.
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Breaking a pollutant linkage — by removing the source through remediation, blocking the pathway through engineering, or controlling exposure at the receptor — is how contamination risk is managed rather than necessarily eliminated.
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Phase 1 Desk Study and Preliminary Risk Assessment
The Phase 1 Desk Study is invariably the starting point. We review all available desk study information — historical Ordnance Survey maps dating back to the mid-19th century, aerial photography, geological and hydrogeological maps, BGS borehole records, Environment Agency data on registered landfills and licensed waste sites, Local Authority records, and commercial environmental databases — to build up a picture of the site's land-use history and its potential for contamination.
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From this, we develop a Conceptual Site Model (CSM) that identifies potential contamination sources, plausible pathways, and sensitive receptors, and we evaluate whether those pollutant linkages are plausible or can be dismissed at desk study stage. The Phase 1 culminates in a Preliminary Risk Assessment that categorises risk as low, intermediate, or high, and recommends whether intrusive investigation is warranted.
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A well-scoped Phase 1 is the foundation of everything that follows. Inadequate desk research at this stage leads to poorly targeted Phase 2 investigations, unexpected findings during construction, and potentially costly remediation requirements identified too late to influence the design.
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Phase 2 Site Investigation and Quantitative Risk Assessment
Where the Phase 1 identifies plausible pollutant linkages that cannot be resolved without intrusive investigation, we scope and report on a Phase 2 Site Investigation. This involves specifying trial pits, boreholes, or window sample locations targeted at the areas of highest potential risk identified by the Conceptual Site Model, and determining appropriate laboratory analysis suites for the contaminants of concern.
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Once laboratory data is returned, we assess results against Generic Assessment Criteria (GAC) — published screening values derived from toxicological and environmental assessment — and, where GAC are exceeded, determine whether exceedances represent a genuine unacceptable risk in the context of your specific site conditions and proposed use, or whether they can be managed by alternative assessment or engineering measures.
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Where generic criteria are not appropriate — perhaps because site conditions differ significantly from default assumptions, or because the generic values are overly conservative for your development type — we can derive site-specific assessment criteria using accepted risk assessment methodologies.
Remediation, Validation, and Discharge of Planning Conditions
Where investigation confirms unacceptable risk that cannot be addressed by assessment alone, we prepare a Remediation Strategy setting out the proposed approach to treating, removing, or containing contamination to make the site suitable for its proposed use. Remediation options range from simple capping and clean cover systems for residential garden areas, to targeted excavation and disposal of hotspot areas, to more complex in-situ or ex-situ treatment of contaminated soils or groundwater.
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Following completion of remediation works, a Validation Report demonstrates to the local authority that the agreed remediation has been implemented effectively and that the site is suitable for use. This is typically the document required to discharge contamination planning conditions and allow occupation to proceed.
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We can manage this process end to end, coordinating with the appointed contractor throughout remediation and preparing the validation evidence required for sign-off.
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Contamination Risk in London and Urban Brownfield Sites
London's development history creates some of the most complex contamination conditions in England. Former gasworks, tanneries, chemical manufacturing works, print works, railway land, historic landfills, and a dense patchwork of former light industrial uses mean that brownfield sites in inner and outer London routinely present a range of contaminants in close proximity, often beneath deep and variable made ground.
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We have experience on sites across Greater London — in inner London boroughs with intensive industrial histories, outer London suburban brownfield sites, and in the South East more broadly — and we understand the particular expectations of London's local authority environmental health teams and the Environment Agency's London area teams in terms of investigation scope and reporting standards.
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For smaller infill sites and residential conversions, we can often scope investigations efficiently to avoid unnecessarily costly fieldwork whilst still satisfying planning requirements. For larger and more complex brownfield allocations, we can phase the investigation to align with your programme and inform remediation design without holding up planning determination.
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Controlled Waters and Groundwater Risk
Where a site is located within a Source Protection Zone, near a principal aquifer, or adjacent to a surface watercourse, the risk of contamination migrating to controlled waters is a key consideration for both the local authority and the Environment Agency. Groundwater risk assessment evaluates the potential for dissolved-phase or free-product contamination to reach controlled water receptors via leaching through the unsaturated zone or lateral groundwater migration.
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Controlled waters risk assessment follows EA LCRM guidance and uses a tiered approach — moving from generic screening against soil leachate criteria, through more detailed assessment of site-specific hydrogeology, to quantitative contaminant transport modelling where required. We engage proactively with the Environment Agency and Lead Local Flood Authorities where groundwater risk is a material planning consideration.
Frequently Asked Questions About Contamination Risk Assessments
How long does a Phase 1 Desk Study take?
For a straightforward residential or small commercial site, a Phase 1 Desk Study and Preliminary Risk Assessment can typically be delivered within 1–2 weeks of instruction, once we have the site location, proposed use, and site layout. Sites with more complex histories, or where additional pre-application consultation with the local authority is advisable, may take slightly longer. If you're working to a tight planning submission deadline, let us know at the outset and we can advise on realistic timescales.
Does every site need a Phase 2 investigation?
No. Many sites — particularly those in Flood Zone 1 with no identified potentially contaminative land uses in the surrounding area, or where historical mapping confirms continuous residential or agricultural use — can be resolved at Phase 1 stage. A well-evidenced Phase 1 that robustly demonstrates the absence of plausible pollutant linkages is often sufficient to satisfy the local authority's contamination condition. We are straightforward with clients where intrusive investigation is not warranted, because unnecessary investigation creates cost and delay for no planning benefit.
What triggers a Phase 2 Site Investigation?
A Phase 2 is warranted where the Phase 1 identifies plausible pollutant linkages that cannot be dismissed without site-specific investigation. This typically occurs where the site history includes potentially contaminative land uses — former industrial or commercial activity, proximity to a landfill, filling operations, or on-site fuel storage — and where those potential sources cannot be ruled out without sampling and analysis. The nature and scope of the Phase 2 is determined by the Conceptual Site Model developed in the Phase 1.
What contaminants are typically tested for?
The suite of laboratory analyses depends on the contaminants of concern identified by the Phase 1 desk study, but commonly includes: total petroleum hydrocarbons (TPH) and BTEX compounds (benzene, toluene, ethylbenzene, xylene) where fuel storage or garages are in the site history; polyaromatic hydrocarbons (PAHs) and coal tar compounds on sites with gasworks, coke works, or rail corridor histories; heavy metals including lead, arsenic, cadmium, chromium, and nickel; pH and sulphate; and asbestos in made ground. On sites with a chemical or solvent use history, chlorinated solvents and other volatile organic compounds may be included.
What is the difference between a Phase 1 and a Phase 2?
A Phase 1 Desk Study is a non-intrusive, desktop review of the site's history, setting, and potential for contamination. It produces a Preliminary Risk Assessment and Conceptual Site Model based on published data, databases, and a site walkover. No ground investigation is undertaken at Phase 1 stage. A Phase 2 Site Investigation involves physical investigation of the ground — trial pits, boreholes, or window samples — and laboratory analysis of collected soil and groundwater samples to characterise contamination and assess risk quantitatively. Phase 2 follows from Phase 1 where intrusive investigation is warranted.
Can you discharge a contamination planning condition for us?
Yes. We regularly prepare and submit the contamination reports required to discharge pre-commencement or pre-occupation planning conditions. This typically involves submission of Phase 1 (and Phase 2 where required) to the planning authority for approval, followed by a Verification Report on completion of any required remediation works. We manage correspondence with the local authority's environmental health and planning teams throughout.
What if contamination is found during construction?
Discovery of unexpected contamination during earthworks is not unusual on brownfield sites. If contamination is encountered that was not identified during pre-planning investigation — or identified but found to be more extensive than anticipated — a revised Remediation Strategy will typically be required. We can respond quickly to unexpected findings during construction, assess the significance of discovered materials, and agree a revised approach with the local authority to keep the programme on track.
Do you work with architects and planning consultants as well as developers?
Yes — we work across the development team. Architects and planning consultants regularly instruct us directly on behalf of their developer clients, particularly where contamination assessment is a pre-application requirement or a condition attached to an appeal permission. We're comfortable working directly with the technical team and feeding into the broader planning application without the developer needing to manage every interface. Clear, jargon-light reporting is important to us, so that findings translate readily into planning submissions.
How much does a Contamination Risk Assessment cost?
Cost depends primarily on the complexity and history of the site. A Phase 1 Desk Study for a straightforward residential or small commercial site typically starts from a few hundred pounds. Phase 2 Site Investigations vary considerably depending on the number of investigation points, laboratory analysis suite, and whether groundwater monitoring is required; intrusive investigation for a small site can range from a few thousand pounds upwards. We provide fixed-fee quotes once we've reviewed the site location and proposed use, so there are no unexpected costs. Contact us for a no-obligation quote.
Do you carry out investigations outside London?
Yes. We work on sites across England, including in the South East, the Midlands, and beyond. Our approach to desk study data and regulatory engagement is consistent regardless of geography, though we ensure we're familiar with the specific expectations of the relevant local planning authority and the Environment Agency area team for each project.
Ready to Progress Your Planning Application?
If your site has a potentially contaminative history or your local authority has requested a contamination risk assessment, get in touch. We'll review your site quickly, advise on the scope of assessment required, and provide a fixed-fee quote. Early engagement — ideally before planning submission — gives you the best chance of avoiding conditions that delay construction.
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Contact us to request a quote or discuss your development site's flood risk.