Development sites can only be assessed as significantly contaminated if all of the following are found to be present, namely
i) A contaminant; a substance in, on or under the land which has the potential to cause harm or to cause pollution of controlled waters
ii) A receptor; something that could be adversely affected by a contaminant, such as people, an ecological system, property, or a water body
iii) A pathway; a route or means by which a receptor can be exposed to or affected by a contaminant
This type of linked combination of contaminant-pathway-receptor is known as a pollutant linkage.
In terms of our ground contamination assessments, we must assess whether or not there is a potential for such a pollutant linkage to exist on any particular site and whether or not further investigation or protective measures are required.
We assess the proposed end use, and the local hydrogeology and hydrology in order to identify the sensitivity of the subject site in terms of human health risk and environmental risk.
Our Phase 1 Desk Studies aim to identify potential sources of ground contamination and then our Phase 2 Ground Investigations are designed with a sampling and testing strategy in place to target the known potential contaminant sources and check for contaminants where encountered at our exploratory positions which include for general coverage of the site.
It should be recognised that most ground investigations only actually sample and test a very small proportion of the total volume of soil at any subject site. This is why a targeted sampling strategy is an essential requirement during designing and organising ground investigations and a Phase 1 Desk Study is the most effective means of identifying potential ground contamination sources at an early stage.
An important aspect of the overall ground contamination assessment and validation regime is that Contractors / Builders are normally expected to notify Local Authority Environmental Protection Officers if unexpected or previously unidentified contamination is found during the Main Groundworks / Construction Phase. This is normally a planning requirement with the aim of ensuring that maximum benefit is gained from the additional knowledge obtained when the groundworker exposes a much larger proportion of the volume of soil on site.
Wherever possible, G7 Geotech aim to work with all stakeholders to maximise knowledge about the sites we are involved in and thereby manage ground-related risks effectively.