PFAS in soil
Calls for a balanced and proportionate approach
PFAS in soil
PFAS keeps surfacing. In case files, in permits, in meetings where no one is quite sure anymore what 'safe' or 'acceptable' really means. The result? Projects stall, budgets spiral. Meanwhile, standards, insights and expectations keep shifting.
In that uncertain context, Witteveen+Bos helps clients translate PFAS into clear, defensible project choices. Always guided by one principle: a balanced and proportionate approach remediating effectively to a level that is both necessary and feasible. What does that mean for your project?
PFAS is everywhere, remediation is complex
In 2021, VITO demonstrated that PFAS is widespread in Flanders. Fifty samples from the topsoil layer (0–20 cm) of non-suspect Flemish soils were analysed. This resulted in an anthropogenic background value of 1.5 µg/kg dry matter for PFOS and 1.0 µg/kg dry matter for PFOA.
In plain terms: this is the “normal” level found in soil purely due to human activity. Levels above this threshold indicate additional contamination from a specific source.
In 2024, VITO repeated the measurements. Soil results were confirmed, but conclusions for groundwater proved more alarming, especially in light of stricter surface water standards.
'Science evolves. Policy tightens. Uncertainty grows among companies, authorities and project owners.'
Why projects often reach a standstill today
The core issue? No one currently knows the full extent of PFAS risks to people and the environment. New studies continuously reshape our understanding of toxicity, dispersion and behaviour. This scientific uncertainty combined with media attention and public concern pushes policy towards ever stricter standards and regulations.
Additional challenges? PFAS originates from multiple sources that often intermingle. Causes are rarely traceable in isolation. That makes PFAS not only an environmental issue, but also a policy minefield. For soil, there are currently no fixed standards only guideline assessment values for investigation and remediation. The focus lies mainly on clear hotspots (e.g. former firefighting training sites) and diffuse contamination affecting soil movement.
PFAS remediation is also technically demanding. Many PFAS compounds degrade poorly and leach easily into groundwater, enabling rapid spread. Excavation and treatment are costly as is the complex remediation of PFAS in groundwater, wastewater and dewatering effluent.
Finally, ultra-short-chain PFAS compounds are barely on the radar. Yet they pose an additional challenge due to higher concentrations and difficult treatment.
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Approach and vision
Witteveen+Bos addresses PFAS across all types of soil investigations: preliminary, exploratory, descriptive, remediation and soil relocation. We are also involved in large-scale PFAS studies, examining PFAS behaviour and developing new remediation techniques.
An internal research unit closely monitors policy, science, methodologies, tools and solutions. This allows us to continuously refine our approach and respond swiftly to new developments.
At the heart of our PFAS vision lies a societal cost–benefit analysis. To what level does remediation create societal value? Which benefits outweigh which costs? What side effects impact the surrounding environment? Our guiding principle: pursue a balanced and proportionate approach removing contamination effectively to a level that is necessary and feasible.
For groundwater, wastewater and dewatering flows, we keep our finger firmly on the pulse. Witteveen+Bos pioneers scientific research in this field and in close collaboration with clients develops concrete, workable treatment solutions tailored to each case.
Is your project stalled by PFAS uncertainty? Let’s bring clarity together.
More information?
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