At a contaminated site in Altstätten, Grundbauberatung-Geoconsulting AG has carried out extensive investigations of contaminated sites since autumn 2019, focusing on the PFC pollutant group (perfluorinated and polyfluorinated chemicals), which has only recently become topical in the treatment of contaminated sites. After initial preliminary investigations in 2019 (in connection with the demolition of buildings, among other things), a technical investigation of contaminated sites was finally carried out from February 2020 with the analysis of numerous solid, leachate and groundwater samples and the corresponding report was completed in September 2020.