CONCEPTUAL SITE MODEL
Information on a site's history and environmental context is used to develop a Conceptual Site Model. This forms a key part of the preliminary risk assessment process and is not included with standard property searches. The Conceptual Site Model can be set out in diagrammatic or written form and identifies where risks to future site users or the surrounding environment could be present.
WHAT IS A CONTAMINANT LINKAGE?
There are three essential elements to the concept of ‘risk’ in the context of land contamination, which combine to form a contaminant linkage. In order for a contaminant linkage to be active, all three of the following elements must be present:
Source: The location from which a contaminative substance (i.e. that which has the potential to cause harm to human health or pollution to controlled waters) is derived.
Pathway: A route or means by which a receptor can be exposed to, or affected by, a source of contamination.
Receptor: Something that could be adversely affected by a contaminant, e.g. a person, an organism, an ecosystem, property, or controlled waters.
DEVELOPMENT OF THE CONCEPTUAL SITE MODEL
Sources, pathways and receptors may commonly exist independently. However, if all three elements are identified, there is the potential for a contaminant linkage to be active, where harm could be caused to either humans (usually site users) or the surrounding environment. The Conceptual Site Model draws attention to where these active contaminant linkages are likely to exist and where further assessment may be necessary.
A simple example showing the development of a basic Conceptual Site Model following a heating oil spill is detailed below: