Two case studies for remediation of PFAS contaminated fire-fighting sites in Norway

In Norway, PFOS has been banned in products and use since 2007. One of the biggest remaining sources of PFOS to the environment is dispersal from contaminated soils. PFOS has been used in firefighting foam agents and therefore has been spread in nature around firefighting training sites. In Norway, as well as in many other countries, airports have been especially targeted, as they are obliged to have regular firefighting practice. Investigations have been conducted at 50 airports in Norway, and PFOS contamination has been identified at a majority of the sites, ranging from low concentrations and small /remaining amounts/residues of PFOS in the soil, to heavily contaminated sites with dispersals to nearby lakes and fjords. The behaviour of PFOS in soil, and its affinity to neither fat nor water, often makes the results from soil investigations uncertain. It appears to be difficult to do representative sampling of the soil, as well as ^finding the allocation of the PFOS within the contaminated areas. At several contaminated sites, the amount of PFOS left in the soil as estimated after soil sampling, has been questioned after conducting risk assessments of water and biota. I.e. high concentrations in biota in nearby lakes have shown that the estimated amount of PFOS in the soil cannot be realistic. This presentation will show two case studies of risk assessment and remediation of PFOS contaminated soil in Norway: Gardermoen airport, an ongoing remediation site; Evenes airport, a small subarctic airport; where a risk assessment based on biota sampling has shown that the local nature is at high risk of negative effects from the dispersals from PFOS-contaminated soil. (author)