What is a desk top study?

A desk top study is the first part of the site investigation process. It involves a desk based collation of documentary evidence such as site history, geology, records of pollution incidents etc. to produce a preliminary conceptual model (see below). This enables the initial risk assessment to be carried out.

I have been asked for a Phase I investigation. What is this?

The same thing. A desk top study may also be referred to as desk study, a phase 1 assessment, phase 1 site assessment, phase 1 site investigation, a soil survey, a site survey and many other names. If in any doubt contact us.

Why is a desk top study required?

A desk top study allows an initial assessment of the likelihood of contamination on the site to be made. It is there for an essential part of the process and forms the basis of subsequent stages if they are required.

Do I need a desk top study?

If you have a condition on your planning permission related to contaminated land then you will need a desk top study unless one has been carried out previously. If you are in any doubt, please feel free to call us and we can advise.

Will a desk top study be enough to discharge the planning condition?

It depends on whether the desk top study concludes that there is the potential for a pollution linkage (see below) or not. However, in many cases we find that a desk top study is adequate to discharge planning conditions of this sort. We never propose carrying out more work unless it is absolutely necessary.

But wouldn’t it be easier to just take a few soil samples?

No. The planning condition will require that a desk top study is carried out before sampling takes place. A site investigation without a desk top study will lead to the condition not being discharged costing both time and money as it will have to be carried out at a later date.

The planning condition requires something called a ‘conceptual model’. What is this?

A conceptual model, conceptual site model or CSM, is a way of describing the way contaminants may interact with ‘receptors’ i.e. site users or controlled waters such as groundwater in aquifers or nearby water courses. It describes the link between the contaminant ‘source’ and the ‘receptor’ via a ‘pathway’ which is how the contaminant may reach the receptor. Examples can be ingestion of the soil, inhalation of dust, leaching of contaminants into an aquifer. If one of these elements is missing then there cannot be said to be a pollutant linkage and therefore the site is not classified as contaminated.