Jersey airport in the northwest of Saint Helier serves over 1.6 million passengers. But a long history of fire training using fire-fighting foams containing perfluorooctane sulphonate (PFOS) on site led to a legacy of contamination in nearby surface soils and water.

To fully understand the extent of the pollution, AECOM was commissioned by the States of Jersey to undertake a detailed hydrogeological assessment of the sand and groundwater in the vicinity of the airport. Both areas support local private domestic and agricultural supplies, and a source of public water supply. The purpose of the investigation was to establish the potential risks posed by the historic disposal of industrial effluent into the ground at the airport fire training ground (FTG) to existing groundwater sources, including the public water supply boreholes.

Following a ground investigation and the development of a hydrogeological conceptual model, we designed and implemented a programme of groundwater remediation.

Measures included:

• Capping the surface of the fire training ground to minimise infiltration and the mobilisation of contaminants
• Excavation and containment of contaminated soils and bedrock
• Evaporation of contaminated waters
• Pump-and-treat system to minimise contaminant migration.

Further contamination at the site has been mitigated by discontinuing use of PFOS-containing foams and strict controls over the wash down areas of the FTG. As part of the remediation works we developed a programme of monitoring to assess the impact of the remedial works on groundwater quality. We now prepare annual monitoring reports on groundwater quality so the airpot is fully aware of the future potential of historic contamination to the site. We have been involved with the airport for over twenty years, helping our client ensure clean, safe water for the local community and environment.