Phase 1 Contamination Risk Assessment — Five-Flat Conversion Adjacent to Railway, Peckham
We prepared a Phase 1 Contamination Risk Assessment for the conversion at 39 Consort Road, Peckham — a site immediately adjacent to a dense historic railway corridor, with nine contamination linkages assessed and a High UXO rating requiring further investigation.
Phase 1 Contamination Risk Assessment — Five-Flat Conversion Adjacent to Railway, Peckham
Location: 39 Consort Road, London, SE15 2PH, London Borough of Southwark | Client: Matra Group Ltd | Services: Phase 1 Preliminary Risk Assessment (Desktop Contamination Study)
Railway-Adjacent Contamination Context
The proposed basement extension and five-flat conversion at 39 Consort Road sits immediately adjacent to a dense historic railway corridor — with extensive sidings, stations and infrastructure extending to 500 metres in all directions. The contamination assessment needed to address this proximity, particularly given the proposed basement construction which increases sensitivity to ground gas ingress and perched groundwater.
We were appointed by Matra Group Ltd to prepare the Phase 1 PRA in accordance with the NPPF (2025) and EA's LCRM guidance (2025).
Groundsure Mapping Artefact
A Groundsure mapping polygon indicated "Railway Sidings, 1920–1938" overlapping the site itself. Investigation confirmed this was a map-boundary artefact — the sidings were never within the site, which has been in continuous residential use throughout its traceable history since at least 1874. This distinction was critical: without it, the site would have been classified as potentially contaminated land, triggering a very different risk assessment approach.
Source-Pathway-Receptor Assessment
The Phase 1 PRA (Groundsure Enviro+Geo Insight ref GS-2VQ-Z57-3FZ-3V7, April 2026) identified nine source-pathway-receptor linkages with risk classifications ranging from Very Low to Moderate/Low:
The adjacent railway corridor (from 12m south) was the dominant potential source, associated with metals, hydrocarbons, and asbestos from historic railway operations. Residual ground gas from shallow Made Ground presented an inhalation risk pathway — particularly relevant given the proposed basement accommodation. A High UXO rating from Zetica screening reflected the site's location in a heavily bombed area of London during WWII. An unspecified Workhouse at 25-34m south (1894-1898) and a Bus Garage at 68m south (1995) were the nearest non-railway off-site sources.
The bedrock aquifer is classified as Secondary A (medium vulnerability), with superficial deposits Unproductive. No Source Protection Zone within 500m. Groundwater flooding risk was negligible on-site.
The overall site-wide risk was judged Low to Moderate/Low and manageable through further investigation and standard construction controls.
Recommendations
The assessment recommended a Stage 2 Detailed UXO Risk Assessment (CIRIA C681); a targeted Phase 2 ground investigation including HSG 248 asbestos-in-soil screening, CIRIA C665 ground-gas monitoring and the standard residential contamination suite; a geoenvironmental watching brief during basement excavation; and early engagement with Network Rail Asset Protection.
Outcome
The Phase 1 PRA provided the London Borough of Southwark with the contamination evidence base for the planning application, demonstrating that the identified risks are manageable through standard investigation and construction controls. The assessment formed part of a comprehensive environmental package that also included the FRA and SuDS Strategy and the Basement Impact Assessment.