Piezometer monitoring during PFAS-contaminated soil remediation experiment
The PHISHES project will benefit from the results of the H2020 Green Deal project PROMISCES (Preventing Recalcitrant Organic Mobile Industrial chemicalS for Circular Economy in the Soil-sediment-water system), which was coordinated by BRGM and recently held its final conference on April 23–24, 2025, at BRGM in Orléans.
One of the main outcomes of the PROMISCES project was an improved understanding of the mobility of persistent and mobile toxic industrial substances, particularly Per- and poly-fluoroalkyl substances (PFAS), within the soil–sediment–groundwater continuum. The project highlighted the key role of PFAS sorption at interfaces (soil–water, air–water) in influencing their mobility in both the unsaturated and saturated zones.
This is particularly relevant for the PHISHES site of the Örnsköldsvik Airport, which is significantly contaminated by these compounds. The site is located approximately 450 km north of Stockholm and is currently being investigated by the partner Swedish Geotechnical Institute (SGI). The PFAS contamination resulted from the historical use of Aqueous Film-Forming Foams (AFFF), leading to very high PFAS concentrations—on the order of 10⁴ to 10⁵ ng/L—in shallow groundwater and intermittent surface water.
Within the PHISHES project, the objective is to refine our understanding of the role of the unsaturated zone by improving existing modelling tools to explicitly account for PFAS sorption at interfaces, particularly the air–water interface in the unsaturated zone. The model will also be further developed to simulate the impacts of changes in land use management on soil contamination and soil functions. In such a highly contaminated “hot spot” site, the initial step in land-use management involves soil remediation to reduce contamination levels.
However, subsurface heterogeneity at the Örnsköldsvik Airport site may hinder conventional remediation techniques due to preferential flow paths. The use of non-Newtonian injection fluids – tested during PROMISCES and other BRGM-led projects – has shown promise in mitigating these effects and enabling more effective flushing of contaminated water.
Further investigations will be carried out at BRGM’s PRIME platform (Platform for Remediation and Innovation in service of Environmental Metrology) to build on these results and simulate the impact of this soil remediation technology on the PFAS plume and soil functions.
Thus, a fruitful synergy is being established within PHISHES through the integration of these two test sites.
Flushing-fluid injection monitoring during PFAS-contaminated soil remediation experiment
Devau, D. Guyonnet, BRGM