We performed a baseline survey of PFAS concentrations, obtaining 12 surface water samples and 23 groundwater samples. Groundwater was sampled to a depth of more than 60 metres. The results of the baseline survey showed:

• Groundwater and surface water downgradient of some firefighting training areas were impacted by PFAS
• Geneva drinking water resource contains only trace amounts of PFAS, but concentrations are well within the strictest drinking water standards.

This baseline campaign enabled the GESDEC environmental authority to define and prioritise several actions to reduce PFAS impacts around the Canton and to be reassured that PFAS are not an issue for the drinking water resource.

All members of our sampling team undergo AECOM PFAS Sampling Training and fully respect the latest version of our PFAS Sampling Guidance. In preparation for the survey, we performed decontamination before analysing the rinsate (water, containing low concentrations of contaminants, resulting from the cleaning of containers) from various items associated with the sampling to verify the absence of PFAS and add to our internal library list of PFAS-free sampling equipment.