Contaminated Land Investigation, Former Gas Works, Aberystwyth


Terra Firma Wales Ltd were retained to undertake desk studies and intrusive investigations, including laboratory and field chemical testing of a brown-field site near Aberystwyth.

The desk study revealed that the site was formerly a Gas Works and consequently Terra Firma Wales Ltd designed a cost-effective ground investigation which allowed the assessment of both Human Health and Groundwater Risks.

The ground investigation revealed the presence of coal tar beneath parts of the site and Terra Firma Wales Ltd designed a comprehensive chemical testing strategy which included soil, leachate, vapour and groundwater testing. The initial test suites were designed to identify the broad range of contaminants associated with former Gas Works.

In the interests of economy Terra Firma Wales Ltd designed a long-term monitoring strategy using selected key indicators of coal-tar contamination. This data was used by Terra Firma Wales Ltd to perform a Groundwater and Surface Water Risk Assessment using the Environment Agency’s P20 Groundwater Risk Assessment Computer Programme.

The Groundwater Risk Assessment Model concluded that the site posed a threat to the aquatic environment.

Using data from the investigation, Terra Firma Wales Ltd delimited the contaminated areas of the site and designed a strategy for the remediation of the site to render it fit for the proposed development.

The remediation strategy allowed construction of the main building to proceed in advance of the remediation since Terra Firma Wales Ltd established that contamination was restricted to areas outside the main development zone.