Phase 1 Desk Study
A preliminary contaminated land assessment that reviews historical mapping, environmental data, and site conditions to identify potential contamination risks and determine whether intrusive investigation is needed.
A Phase 1 desk study (also called a Phase 1 preliminary risk assessment or Phase 1 environmental assessment) is the first stage of contaminated land investigation under the Land Contamination Risk Management (LCRM) framework. It is a desk-based exercise that evaluates whether a site may be affected by contamination from historical or current land uses.
The Phase 1 desk study typically includes:
- Historical mapping review: Ordnance Survey maps from the earliest available editions to the present day, identifying former land uses such as industrial operations, fuel storage, waste disposal, or chemical manufacturing that may have left contamination
- Environmental database search: A commercial data report covering Environment Agency records, local authority pollution registers, historical tank and trade directory records, landfill boundaries, and other regulatory datasets
- Geological and hydrogeological review: BGS mapping, borehole records, and groundwater vulnerability data to understand the ground conditions and potential pathways for contaminant migration
- Site walkover: A physical inspection of the site and surrounding area to identify visible evidence of contamination (staining, odours, waste materials), confirm current land use, and assess the condition of any existing structures
- Regulatory consultation: Contact with the local authority Environmental Health department and, where relevant, the Environment Agency to obtain any additional records
The output of the Phase 1 desk study is a Conceptual Site Model (CSM) that identifies potential source-pathway-receptor linkages. Each linkage is assessed against the LCRM framework to classify risk as very low, low, moderate, or high.
If the Phase 1 assessment identifies moderate or high risk pollutant linkages, a Phase 2 site investigation will be recommended to obtain ground truth data through soil, groundwater, and gas sampling.
Phase 1 desk studies are routinely required by planning conditions. Many local planning authorities now require a Phase 1 report to be submitted with the planning application itself rather than as a pre-commencement condition.
Aegaea delivers Phase 1 desk studies as part of our contaminated land assessment service, with reports that follow the LCRM framework and are accepted by Environmental Health Officers and the Environment Agency.