Contaminated Land and the Planning Process

When a planning application is submitted, both the Environment Agency (and their equivalent, SEPA in Scotland, NIEA in Northern Ireland) and the Local Authority Contaminated Land Officers will be consulted as part of the 13 week planning process. They will normally search their databases and should there be an historical land use which may have contaminated the underlying soil and groundwater, or they have local knowledge to suspect contamination, they will apply a condition that an assessment of the land be undertaken and submitted to them for approval. This assessment will normally be required to establish whether any contaminants are present in the ground, to identify any unacceptable risks and to determine whether any clean up is required to allow development to safely commence.

Initial Reporting Requirements

They often use terms such as Phase I or Desk Study which, as the name suggests, is a desk based report collecting together all available documentary information for a site such as historical maps, geology, past land use, nearest watercourses etc. This data can then be collated and assessed on a basic level to ascertain whether there are any potential risks to future site users or the environment and whether there is a requirement for further works. The costs for a Desk Study Report typically range between £500 and £5,000 depending upon the size and complexity of the site.

Site Investigation

If the Desk Study report identifies potentially contaminative past uses and/or potentially unacceptable risks, then there may be a requirement for further assessment. Once ground is broken and samples obtained for analyses, this is generally referred to as Phase II or a Site Investigation.

This comprises an intrusive survey where ground is broken to obtain soil, groundwater and ground gas samples. Typically this can be acheived through excavating trial pits, drilling boreholes and installing monitoring wells. Samples are normally obtained and sent to laboratories for testing using accredited techniques. The results of the testing are generally collated into a report including logs, drawings, photographs and certificates of analyses. The results of the testing are normally compared to the relevent assessment guidelines and conclusions are drawnm and recommendation made for further action if required.

The outcome of a site investigation will generally either be: that testing confirms contaminant concentrations to be within acceptable limits, or that contamination has been identified which required more detailed risk assessment.

The price of a site investigation is typically between £5,000 to £50,000 but can extend upwards, again depending upon the size and complexity of the site.

Detailed Risk Assessment

Within the UK, the significance of contamination is generally assessed within a risk based framework. A ‘Conceptual Site Model’ must be developed to demonstrate all of the potential sources of contamination, to show the pathways by which this contamination can travel and to identify sensitive receptors that could be impacted by the contamination. Where there is a clear route from the source of contamination through to a sensitive receptor, this is referred to as a plausible pollutant linkage.

To take this a stage further, a contaminant concentration must be identified below which the risk to a given receptor is acceptable. The calculation of such figures can be a complex process. Detailed risk assessment methodologies are laid out in government guidance and follow a tiered approach.

The process of Quantitative Risk Assessment is a specialist field and typically costs between £5,000 and £10,000 to complete.