ENSOr v6
Managing Emerging Contaminants for healthy soils: Are we ready?!
Full program online, registations are open!
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Day 1, Monday, October 13
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9:00 - 9:30
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Welcome coffee
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9:30 - 9:50
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Welcome and introduction - setting the scene
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Johan Ceenaeme (OVAM, Belgium)
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9:50 - 10:10
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Societal cost and benefits analysis for PFAS in soil and groundwater
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Griet Van Gestel (OVAM, Belgium)
A high-level societal cost-benefit analysis (SCBA) for managing PFAS contamination in soil and groundwater in Flanders was developed, including the evaluation of the framework for earthmoving. The study involves creating a methodology, analyzing case studies, and formulating policy recommendations based on environmental, human health, and economic impacts. Data gaps were identified, different management alternatives were evaluated, and the effects and costs of remediation strategies were estimated.
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10:10 - 10:30
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Demonstrating the need for a more sustainable and risk-based approach for dealing with PFAS
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Hans Slenders (Arcadis, The Netherlands)
Poly- and per- Fluorinated Alkyl Substances (PFAS) are gaining increasing societal and regulatory attention due to evolving understanding of the potential risks they pose to people and ecological systems. It is obvious that PFAS are harmful to men and the environment. They are persistent, mobile and toxic, and are found everywhere. The need for appropriate regulation is evident including, for example, the need to set suitable environmental quality standards (EQS).Although the science on the effects of PFAS is increasing rapidly, there is still a lot of uncertainty about the exact effects and at what level they do occur. In those cases the precautionary approach the EU opts for may seem a safe approach, but the proposed Environmental Quality Standards for surface and groundwater more often lie below background level than that they are met in most European ground- and surface waters, especially when they are expressed in PFOA equivalents (see Table 1 for references). This implies that the proposed targets either cannot be met or would cause significant and unsustainable impacts in attempting to meet them. Proposed EQS values that are more stringent than ambient or anthropogenic background levels should be avoided unless achieving the EQS is practicably achievable or necessary. As such, there is a need for a more proportionate and sustainable risk-based underpinning of the proposed target values.In our proposed presentation we intend to highlight the discrepancy between EQSs and ambient levels, and demonstrate with clear conceptual graphs that going beyond ambient values with target values will cause more harm than good.Given the uncertainties in the exact health effects the need to achieve the proposed EQS is too uncertain to justify action, given the considerable impacts this in turn would likely create and already creates. Examples of such impacts are for instance: water treatment facilities, groundwater extraction systems for construction purposes and other discharges that are burdened with target values below background values. Moreover, given the enormous costs and wider impacts of actions, we observe a stagnation in tackling the necessary hot-spot remediations or emissions. Necessary permits and agreements are often halted due to the impossibility to meet required standards or budgets. Too stringent EQSs work counterproductive.Whereas both the Foodstuff Regulation and REACH look into the impacts or cost-benefits of setting regulatory limits, to date this is not the case for the EQS proposed by the WFD/GWD. There is a need for a better quantitative underpinning of the actual risks of PFAS and a clear balance between the benefits and impacts of setting EQSs or target values for the environment.
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10:30 - 11:00
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Coffee break
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11:00 - 11:20
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Dutch PFAS approach & dilemma's
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Mathijs van de Waardt (RWS, The Netherlands) and Michiel Gadella (RWS, The Netherlands)
The Netherlands, like other European countries, has been confronted with the uncomfortable reality of the ubiquitous presence of PFAS in soil and (ground)water. In response policy has been developed in three pillars:- Pillar 1: Prevention. The Netherlands supports the EU-wide proposed PFAS restriction under REACH. The Netherlands is reviewing national discharge permits and encouraging companies to implement PFAS alternatives in their operations.
- Pillar 2: Reuse of soil and sediment. A temporary PFAS action framework has been implemented in addition to the existing framework for dealing with diffusely contaminated soil and sediment, ensuring that the reuse of excavated soil and dredged sediments remains possible as well as protecting the environment.
- Pillar 3: Addressing point sources/brownfields. PFAS point source locations are being identified and a programmatic approach is being developed to remediate these locations based on a prioritization.
The presentation focuses on Pillar 3. In the Netherlands, the competent authority for contaminated soil is further decentralized in 2024 to the level of 342 municipalities. Water boards and provinces also have responsibilities based on transitional provisions and the responsibility for the physical environment. This division of powers aligns well with the level at which decisions on spatial planning for the physical environment are made. The various levels of government (national, provincial, municipal, and water board) have made agreements regarding the inventory and approach to point source locations and national funding. Within these agreements, work is underway to identify point source locations and prioritize them. We will present this collaboration and highlight several dilemmas we face, for example regarding the WFD in relation to cost-effective remediation and the relationship between the "polluter pays" principle, the awareness of the polluters about the environmental impact of PFAS and the possibilities for deploying government funds. We’ll ask Ensor- participants to share their thoughts on these dilemmas.
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11:20 - 11:40
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Emerging Contaminants - discussing the revision of operational trigger values in Austria
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Dietmar Müller-Grabherr (Environment Agency, Austria)
Since more than 20 years operational trigger values for soil and groundwater in Austria are discussed by a working group and published through the Austrian Standards Institute. By May 2025 revisions for implementing new tox-data have been completed and are providing for new trigger values on PFAS and revised trigger values for lead. Complemented by case studies the presentation will allow insights to working group discussions, discuss environmental goals in policy vs good chemical conditions in practice, as well as assessing risks or exposure.Policy frames are only work well when we understand and charactise the context in a sound systemic and appropriate manner. Concluding remarks shall discuss questions of possible key aspects like the ALARA-principle allowing for more adaptiveness in contaminated land management.
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11:40 - 12:00
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Local pollutions of PFAS in soil and groundwater – Feedback from Belgium (Wallonia)
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Thomas Lambrechts (Public Service of Wallonia, Belgium)
The SPW – Public Service of Wallonia (southern region of Belgium) published updated guidelines for PFAS in March 2025. These guidelines are intended for soil experts conducting studies on local soil and groundwater pollutions, within the legislative framework of the “Soil Decree”.These guidelines are based on the results of several years of soil studies on PFAS and a comprehensive literature review. They were developed with the technical support of two public scientific institutes, ISSeP and SPAQuE.These guidelines aim to address PFAS-related risk activities, analytical methods, interpretation of concentrations in relation to threshold values, and risk assessment for human health and the environment.The objective of this presentation is to provide feedback on specific topics.Regarding PFAS-related risk activities, one of the main challenges is that industrial entities are often unaware they are using PFAS in their processes, due to the complexity of interpreting safety data sheets. Another challenge is the historical and current backfilling of industrial or commercial land, where certain types of materials containing PFAS are used.The PFAS issue necessitates a thorough review of investigation strategies used for traditional pollutants. At several sites, experts relied solely on soil analyses, thus overlooking significant contamination. Groundwater and surface water analyses should be conducted almost systematically, but this message is difficult to convey to soil experts. Moreover, these water analyses sometimes entail significant additional costs, necessitating the definition of customized investigation strategies for each site.In the absence of European directives, each country sets its own threshold values for soil, unlike for groundwater. We work with specific values for each measured PFAS, rather than a sum or weighted sum. These standards are based on two risk values, one for human health and the other for leaching risks. This system is constantly being evaluated to ensure our values are consolidated.
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12:00 - 12:20
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PFAS Management and Policy in Europe: Results of the COMMON FORUM Survey 2025
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Griet Van Gestel (OVAM, Belgium)
To update the 2020 position paper 'PFAS Memorandum', the COMMON FORUM PFAS-team launched a new survey in 2025. In the presentation the results of these survey will be presented. This includes data on monitoring of PFAS in different environmental media, on PFAS risk activities, information on the progress of inventories and investigations of PFAS contaminated sites, as well as on PFAS policies and regulations in different European countries.
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12:20 - 12:40
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PFAS in Contaminated Land – Scope of Analysis and Soil Risk Relevance
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Patrick van Hees (Eurofins Food & Feed Testing Sweden AB, Sweden)
BackgroundPer- and polyfluoroalkyl substances (PFAS) are known for their persistence and widespread presence. While exposure through food and water is well-documented, inhalation—especially indoors—is gaining attention, as people spend ~90% of their time indoors. A 2023 US EPA report confirmed PFAS in air, soil, and landfill gas at contaminated sites, but data on soil gas at AFFF-impacted locations remain limited. Volatile/semi-volatile neutral PFAS, such as fluorotelomer alcohols (FTOHs) and PreFOS (Me/Et-FOSE/A), are common in air but often excluded from regulations.AimThe study investigates air as a potential PFAS exposure pathway at contaminated sites. The approach can largely be compared to sampling and risk assessment of e.g. chlorinated solvents. Another objective is to investigate to what degree air reflects the overall PFAS contamination. Focus areas include sampling, compound profiles, and gas/particle phase distribution in indoor air and soil gas, with comparisons to dust samples. The paper addresses current insights but potentially also the need for a future extended risk assessment.ConclusionAir sampling in homes/offices detected 6:2–12:2 FTOHs and Me/Et-FOSE/A (<1–20 ng/m³), mainly in the gas phase. Similar compounds were found in soil gas at a Swedish airport, where 6:2 FTOH levels (2–58 ng/m³) aligned with 6:2 FTAB in soil. A fire station/training site showed more complex mixtures and higher levels (max 250 ng/m³ 8:2 FTOH). PFAS levels and composition may indicate contamination but must be assessed against background levels. Dust offered complementary data but was not directly comparable. Calculated exposure estimates varied widely (1–>100% of TWI for PFAS4), the highest for childrenObservations indicate that air deserves further investigation as an exposure pathway, and more knowledge is needed to support risk assessment and regulatory development. The same applies to the use of air measurements as a tool for evaluating the degree of contamination.
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12:40 - 13:30
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Lunch
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13:30 - 14:45
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Workshop: Approach for soil research to non-regulated pesticides
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Daniël Rits (Witteveen+Bos)
Pesticides play an important role in agriculture, protecting crops from diseases, pests, and weeds. However, their use is increasingly contentious due to potential negative impacts on human health and the environment. Many new pesticides contain a mixture of non-regulated substances that are rarely investigated in soil studies. To address this gap, we developed an Action Framework for environmental soil investigations into such pesticides.The framework builds on a literature review, analysis of approval procedures, legal assessments, and expert interviews. We assessed potential effects on soil, water, and public health, and identified 20 priority substances that warrant soil investigation. Selection was based on usage levels, toxicity, persistence, bioaccumulation, and mobility.
The framework offers policymakers, soil advisors, and practitioners science-based guidance for systematic, transparent investigations. It supports authorities and organizations in designing effective research to protect citizens and ecosystems from risks of non-regulated pesticides. The legal context (Dutch and European law) and implications of soil contamination were also outlined.Although developed for the West-Holland region, the framework is adaptable elsewhere. It emphasizes iterative evaluation, allowing updates as new knowledge emerges. Beyond its practical use, it stimulates dialogue on pesticide risks, encouraging collaboration between governments, scientists, and the agricultural sector for integrated decision-making.At ENSOr, we will present the framework and its current status. We will discuss challenges posed by pesticides, existing regulations, key substances for investigation, and the proposed research strategy. The session will include open dialogue to connect with participants’ experiences and to explore interest in forming a Community of Practice (CoP) for further collaboration. -
Workshop: Nature-based solutions for diffuse pollution
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Kris Van Looy (OVAM, Belgium)
On the one hand, we can not apply hard remediation techniques for the extensive areas of diffusely polluted land,on the other hand, we're only on the start of fully apprehending the potential of nature's remediation capacities, in the biotic groups that are the decomposers of organic compounds.The mycoremediation or fungi-based remediation methods are now moreover used to decontaminate soils, since many species of fungi have strong enzymatic capacities to break down organic components. In LIFE projects MYSOIL and PFASTER field scale application is realized.The biostimulated phytoremediation techniques offer enhanced capacities for the traditional phytoremediation approaches, benefiting from the understanding of plant-soil interactions that are ruled by micro-organisms (bacteria, mycorrhiza) that not only stimulate exchange between plant and soil, but at the same time decompose certain compounds -
Workshop: Soil Monitoring in Transition: Prioritising what to measure
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Annegret Biegel-Engler (UBA, Germany)and Laetitia Six (OVAM,Belgium)
With the upcoming European Soil Monitoring Law (SML) aiming for healthy soils by 2050, Member States face a critical challenge: how to define and implement effective soil monitoring strategies. This workshop dives into the development of a European soil watch list — a key tool to identify and prioritise contaminants of emerging concern (CECs) that pose risks to soil health, human well-being, and ecosystems.
Drawing on the NORMAN network’s activities, we will explore:
- How to select priority substances for soil monitoring?
- Which criteria to use for prioritization?
- How to balance analytical feasibility with environmental urgency?
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Workshop: Collaborating on Emerging Contaminants: how can EmConSoil contribute?
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Pieter Schrooten (EmConSoil, Belgium)The EmConSoil workshop at Aquaconsoil has identified a strong need for more collaboration from stakeholders within the field of soil & groundwater. The goal of this workshop is to explore how EmConSoil can facilitate this by focussing on the following steps:- Identify collaboration challenges in soil & groundwater management with emerging contaminants.
- Explore how EmConSoil can act as a facilitator across regional and global levels.
- Develop shared principles and facilitator roles for EmConSoil.
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Workshop: Injured landscape -what if soil could speak?
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Tim Joye (Reaktor21, Belgium)Injured Landscape is a 25-minute presentation and 65 mins workshop that explores how international artists, designers, and architects are advancing soil literacy and pioneering creative soil remediation. Through compelling examples from around the world, we showcase how community art, speculative design, and participatory architecture can turn polluted ground into fertile space—physically, culturally, and symbolically.We ask: What if soil could speak—and what if our neighborhoods listened?
Together, we explore how creative trajectories in local communities can address contaminated soils and water, not only with technical solutions but through imaginative, community-centered approaches that foster care, awareness, and deep connection to place.
After the presentation, we invite participants to co-create a 'moonshot project' in small groups. Through drawing and idea mapping, we design ambitious, even fantastical remediation concepts—only limited by the boundaries of our imagination, not by budget or bureaucracy. A concrete case sets the stage for wild yet rooted ideas to emerg -
Workshop: Impact of trigger values - the cost of action versus inaction
More information
Johan Ceenaeme (OVAM, Belgium)
The presentations at this ENSOr6 demonstrate that balancing the costs and benefits of addressing PFAS contamination is a key issue. The trigger values developed by several countries take into account the precautionary principle and potential future risks to human health. However, with most methodologies we use to derive trigger values for soil and groundwater from toxicological values, we find that in some cases these are lower than the anthropogenic background values in various media. The costs of addressing PFAS contamination are also often higher than those for other conventional contaminants. In the workshop, we will discuss how we strike this challenging balance.
This workshop can also provide an initial impetus for developing a shared vision between industry, consultants, such as those represented in NICOLE, scientists, and policymakers, such as those represented in Common Forum.
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14:45 - 15:15
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Coffee break
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15:15 - 16:30
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Workshop: Approach for soil research to non-regulated pesticides
More information
Daniël Rits (Witteveen+Bos)
Pesticides play an important role in agriculture, protecting crops from diseases, pests, and weeds. However, their use is increasingly contentious due to potential negative impacts on human health and the environment. Many new pesticides contain a mixture of non-regulated substances that are rarely investigated in soil studies. To address this gap, we developed an Action Framework for environmental soil investigations into such pesticides.The framework builds on a literature review, analysis of approval procedures, legal assessments, and expert interviews. We assessed potential effects on soil, water, and public health, and identified 20 priority substances that warrant soil investigation. Selection was based on usage levels, toxicity, persistence, bioaccumulation, and mobility.
The framework offers policymakers, soil advisors, and practitioners science-based guidance for systematic, transparent investigations. It supports authorities and organizations in designing effective research to protect citizens and ecosystems from risks of non-regulated pesticides. The legal context (Dutch and European law) and implications of soil contamination were also outlined.Although developed for the West-Holland region, the framework is adaptable elsewhere. It emphasizes iterative evaluation, allowing updates as new knowledge emerges. Beyond its practical use, it stimulates dialogue on pesticide risks, encouraging collaboration between governments, scientists, and the agricultural sector for integrated decision-making.At ENSOr, we will present the framework and its current status. We will discuss challenges posed by pesticides, existing regulations, key substances for investigation, and the proposed research strategy. The session will include open dialogue to connect with participants’ experiences and to explore interest in forming a Community of Practice (CoP) for further collaboration. -
Workshop: Nature-based solutions for diffuse pollution
More information
Kris Van Looy (OVAM, Belgium)
On the one hand, we can not apply hard remediation techniques for the extensive areas of diffusely polluted land,on the other hand, we're only on the start of fully apprehending the potential of nature's remediation capacities, in the biotic groups that are the decomposers of organic compounds.The mycoremediation or fungi-based remediation methods are now moreover used to decontaminate soils, since many species of fungi have strong enzymatic capacities to break down organic components. In LIFE projects MYSOIL and PFASTER field scale application is realized.The biostimulated phytoremediation techniques offer enhanced capacities for the traditional phytoremediation approaches, benefiting from the understanding of plant-soil interactions that are ruled by micro-organisms (bacteria, mycorrhiza) that not only stimulate exchange between plant and soil, but at the same time decompose certain compounds -
Workshop: Soil Monitoring in Transition: Prioritising what to measure
More information
Annegret Biegel-Engler (UBA, Germany)and Laetitia Six (OVAM,Belgium)
With the upcoming European Soil Monitoring Law (SML) aiming for healthy soils by 2050, Member States face a critical challenge: how to define and implement effective soil monitoring strategies. This workshop dives into the development of a European soil watch list — a key tool to identify and prioritise contaminants of emerging concern (CECs) that pose risks to soil health, human well-being, and ecosystems.
Drawing on the NORMAN network’s activities, we will explore:
- How to select priority substances for soil monitoring?
- Which criteria to use for prioritization?
- How to balance analytical feasibility with environmental urgency?
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Workshop: Collaborating on Emerging Contaminants: how can EmConSoil contribute?
More information
Pieter Schrooten (EmConSoil, Belgium)The EmConSoil workshop at Aquaconsoil has identified a strong need for more collaboration from stakeholders within the field of soil & groundwater. The goal of this workshop is to explore how EmConSoil can facilitate this by focussing on the following steps:- Identify collaboration challenges in soil & groundwater management with emerging contaminants.
- Explore how EmConSoil can act as a facilitator across regional and global levels.
- Develop shared principles and facilitator roles for EmConSoil.
-
Workshop: Injured landscape -what if soil could speak?
More information
Tim Joye (Reaktor21, Belgium)Injured Landscape is a 25-minute presentation and 65 mins workshop that explores how international artists, designers, and architects are advancing soil literacy and pioneering creative soil remediation. Through compelling examples from around the world, we showcase how community art, speculative design, and participatory architecture can turn polluted ground into fertile space—physically, culturally, and symbolically.We ask: What if soil could speak—and what if our neighborhoods listened?
Together, we explore how creative trajectories in local communities can address contaminated soils and water, not only with technical solutions but through imaginative, community-centered approaches that foster care, awareness, and deep connection to place.
After the presentation, we invite participants to co-create a 'moonshot project' in small groups. Through drawing and idea mapping, we design ambitious, even fantastical remediation concepts—only limited by the boundaries of our imagination, not by budget or bureaucracy. A concrete case sets the stage for wild yet rooted ideas to emerg -
Workshop: Impact of trigger values - the cost of action versus inaction
More information
Johan Ceenaeme (OVAM, Belgium)
The presentations at this ENSOr6 demonstrate that balancing the costs and benefits of addressing PFAS contamination is a key issue. The trigger values developed by several countries take into account the precautionary principle and potential future risks to human health. However, with most methodologies we use to derive trigger values for soil and groundwater from toxicological values, we find that in some cases these are lower than the anthropogenic background values in various media. The costs of addressing PFAS contamination are also often higher than those for other conventional contaminants. In the workshop, we will discuss how we strike this challenging balance.
This workshop can also provide an initial impetus for developing a shared vision between industry, consultants, such as those represented in NICOLE, scientists, and policymakers, such as those represented in Common Forum.
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16:30 - 17:00
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Documentary on Brownfields
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17:00 - 19:30
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Apero and network dinner
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Day 2, Tuesday, October 14
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8:30 - 9:00
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Welcome coffee
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9:00 - 9:10
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Pilot Scale Thermal Soil PFAS Remediation Test
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Søren Eriksen (Krüger A/S, Søborg, Denmark)
Background: Lab scale studies on thermal soil PFAS remediation have demonstrated reduction of targeted PFAS to below 1 μg/kg at 350-400°C as reported by a number of investigators. In house lab scale testing has demonstrated high degrees of PFAS mineralization.The purpose of this pilot scale study is to:- Verify the efficiency of thermal remediation
- Optimize PFAS mineralization
- Use all analytical methods available including real time gas analysis by high resolution mass spectrometry (HRMS)
Methodology: A 20 m3 heated box is set up to treat 36 t of soil at up to 500°C. Soil, vapors and condensate (soil initial water content extracted during heating), are analyzed.Results: The planned heat treatment has been completed with soil temperatures ranging from 250 to 500°C. The treatment temperature has been maintained for 4 weeks.36 soil samples have been analysed. None of the 22 target PFAS are detected in the soil samples treated at above 350°C. 3 samples treated at 250°C have a sum of 22 PFAS ranging from 0.1 to 2.1 µg/kg. The sum of 22 PFAS concentrations prior to treatment ranged from 65 to 390 µg/kg with an average of 190 µg/kg.The sum of 22 PFAS in the condensate collected during the soil dry out ranged from 25 to 100 ng/L. In total 0.004% of the 22 PFAS mass was found in the condensate.
Vapor analysis by OTM 45, OTM 50 and real time HRMS has identified a number of PFAS compounds.
Conclusion: The pilot test has confirmed the 350°C treatment temperature being sufficient for 22 PFAS thermal soil remediation.The chosen thermal treatment strategy has resulted in limited volatilization of PFAS thus optimizing the vapor residence time in contact with the hot soil allowing time for degradation and mineralization.
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9:10 - 9:20
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Breaking the cycle : the power of activated carbon in PFAS removal and destruction
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Wouter Lema (DESOTEC, Belgium)
Per- and polyfluoroalkyl substances (PFAS) are a pressing global challenge due to their persistence in the environment and adverse health effects. France and Belgium were among the first countries to tackle this issue. DESOTEC, an international environmental services company, provides sustainable mobile filtration solutions based on activated carbon, a proven and effective method for PFAS removal from liquid and gaseous streams. Recognized as a Best Available Technology (BAT) under the Stockholm Convention (March 2021), activated carbon offers a versatile and robust approach to addressing PFAS contamination.
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9:20 - 9:30
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isoFLUX - Isotopes meet mass flux – new tool for precise quantification of pollutant degradation in contaminated aquifers
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Marjan Joris (iFLUX sampling, Belgium)
Due to increasing scarcity of drinking water caused by contaminants like pesticides, understanding their behavior in the water cycle is a growing priority. In contaminant hydrogeology, it's essential to assess the sustainable reduction of contaminant mass flux in groundwater. Degradation is the most critical process for natural contaminant removal. Determining how much mass flux is reduced by degradation is key to evaluating natural attenuation (NA) as a cost-effective strategy for managing polluted aquifers.Compound-specific isotope analysis (CSIA) is the most accurate method to quantify in situ degradation, as shifts in isotope ratios directly reflect degradation processes and allow source characterization via isotope fingerprints.The innovative IsoFLUX method combines CSIA with iFLUX passive samplers for the first time to precisely assess pesticide mass flux reduction due to degradation. This approach provides essential data to model contaminant plume size and behavior over time and space. It also helps determine the contribution of different pollution sources, supporting cost-efficient strategies for source elimination and emission prevention. IsoFLUX thus serves as a forensic tool to identify and differentiate multiple sources and quantify their mass-flow-based contributions.The developed samplers offer highly sensitive and precise measurements of contaminant fluxes, applicable to pesticides, BTEX, and chlorinated solvents (CVOCs). Lab tests under static and dynamic conditions showed highly accurate isotope analysis and significantly lower detection limits compared to conventional methods. A successful alpha test at a field site demonstrated IsoFLUX's performance in analyzing phenoxyacids (e.g., dichlorprop). Interpretation frameworks using CSIA and flux data enhance the IsoFLUX approach, enabling reliable assessment of degradation and source impact.By refining conceptual models and improving aquifer management, IsoFLUX significantly contributes to groundwater risk assessment, allowing more accurate predictions of contaminant impacts on critical receptors like drinking water wells and surface waters.
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9:30 - 9:40
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In-situ PFAS stabilization by injection of surface modified clay (InSuFix Project)
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Hans Baillieul (Sodecon, Belgium)
New challenges demand new approaches.With the support of KIS (Knowledge Center for Innovative remediation Solutions), the applicability of innovative soil and groundwater remediation methods is being tested. One of the seven selected proposals is InSuFix, a project that investigates the use of organo-clay to immobilize PFAS contamination.KIS encourages collaboration between research institutes, industries, innovative technology providers and developers and authorities to improve and accelerate the testing and outcomes as well as to define a sustainable policy regarding remediation and management of PFAS in soil, sediment and groundwater.InSuFix aimes at improving the implementation of remediation and treatment for PFAS contamination. This project tests whether and under which conditions in-situ injection of organo-clay can remove PFAS contaminants from the aqueous phase and immobilize PFAS contamination in soil and groundwater.Given that PFAS contamination is widely distributed in the environment and toxic effects can occur at very low concentrations, careful consideration must be given to which contaminants need to be removed and when in-situ control is a better option. Currently, there are more challenges than solutions.Strong PartnershipsMaking the right choices is crucial. It is essential to understand and improve the applicability of available technologies while also recognizing their limitations. A good approach requires correct prioritization. To this end, it is important to bring together information and expertise from various fields and disciplines.Therefore, effective collaboration between partners from different sectors and research institutions is essential.The InSuFix project involves a diverse mix of actors, such as:- Sodecon, a remediation contractor with expertise in using organo-clay for water treatment and for the treatment of excavated soils.
- Injectis, a remediation expert with patented injection technology (SPIN®), suitable for improved injection in heterogeneous soils.
- VITO, a Flemish research institute with PFAS experts, laboratories, and testing facilities.
- BAC (Brussels Airport Company), site owner.
- Port of Antwerp, site owner.
The partners leverage their strengths and expertise to test innovative remediation techniques, supported and encouraged by the Flemish government, which provides funding to test new methods and technologies. The partners work in close collaboration with contamination and remediation consultants Witteveen & Bos and ABO, iFLUX as a groundwater monitoring expert, and EniSSA, an expert in High Resolution Site Characterization (HRSC).Project DescriptionOrgano-clay (OC) has a number of properties that make it more suitable than other adsorbents (e.g. activated carbon) for immobilizing PFAS in soil. OC has a higher adsorption capacity, can also adsorb short-chain PFAS and retains its adsorption capacity even at high pH values. Currently, OC can already be applied by mixing with soil. This project evaluates whether OC can also be applied by injection into the saturated zone via the SPIN® injection technology.Initial tests are set up in laboratory conditions. The laboratory at Sodecon allows for testing the capacity and limitations of organo-clay and its interactions with different PFAS in a controlled environment. VITO will simulate long-term stability testing by accelerating weathering processes.In addition to the laboratory testing, the products and technology will be tested in the field at two sites: one at Brussels Airport and the other at a firefighting training site in the Port of Antwerp. Since extensive soil investigations have already been carried out, there is good knowledge on the geology and the PFAS contamination at both sites. The site owners are project partners, seeking the best methods and technologies to remediate PFAS contamination on their site. Consultants who carried out the earlier investigations are actively involved. The information, available results, uncertainties, and gaps from the earlier investigations will be shared and discussed to adequately prepare and monitor on the pilot testing.During the pilot tests, Injectis will optimize both the injection parameters and the particle size distribution of the OC in order to distribute the adsorbent as homogeneous as possible in the treatment area. The pilot tests will be carried out at the two sites characterized by a different hydrogeology and PFAS signatures. The results of the pilot tests will be used to determine the radius of influence in heterogeneous and less permeable soils, to evaluate the applicability and limitations of the technology, and to understand the direct effects in source zones, as well as longer-term effects downstream. These results will be compared with other remediation techniques and used to develop a remediation plan for the two test sites.Outcomes of the project will be presented to and discussed with the broader stakeholder group, including members of the KIS program, to encourage the market to tackle challenges and make the right choices in managing and remediating PFAS contamination.To conclude: collaboration between various partners, including research institutes, technology providers, and authorities, is crucial for the success of the project and for accelerating the development of effective and sustainable solutions for PFAS remediation.
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9:40 - 9:50
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Recover, remediate, reuse: The untapped potential of PFAS soil remediation
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Eunan Kelly (CDE Group, Northern Ireland) and Clemence Badier (CDE Group, United Kingdom)
Soil washing is recognised as the most effective and widely available treatment for PFAS-contaminated soils. This proven remediation technology physically separates PFAS particles contained in soil, reducing contamination levels below regulatory thresholds while enabling 70–80% material recovery.Combined with advanced water treatment systems, integrated soil washing solutions offer the precision and adaptability needed to manage the complexity of PFAS-contaminated sites. These systems are capable of addressing co-contaminants such as hydrocarbons and heavy metals, ensuring compliance with evolving environmental regulations.The clean recovered material can be used for soil remediation to reclaim land impacted by pollution or for value creation to produce reusable materials for construction and infrastructure projects - turning environmental liabilities into valuable resources. Soil washing stands out as a scalable, sustainable, and future-ready solution for PFAS treatment.
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9:50 - 10:00
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PFAS in environmental media at the Belgian coast
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Johan Gemoets (VITO, Belgium)
At five locations along the Belgian coast, Per- and PolyFluoroAlkyl Substances (PFAS) were measured in sea foam, sea water, soil and ambient air.Seafoam samples were collected during three consecutive years. Foam condensates were analyzed for PFAS with target-analysis (UPLC-MS/MS). They were also screened for other contaminants with nontarget analysis (NTA, by UPLC-MS/MS). Target analyses revealed elevated and variable concentrations of PFAS in seafoam (8,7 – 2400 μg/L condensed foam). PFOS was dominant, while the 4 EFSA-PFAS accounted for approximately 90% of the sum of PFAS. Longer chain PFAS were more abundant than short chain PFAS. NTA results indicated that many other PFAS-compounds are present in sea foam, not measured with target analyses. Sea foam was also enriched with other emerging contaminants such as pharmaceuticals, hormones, hormone disrupting chemicals, pesticides industrial chemicals. Concentrations of PFAS in seawater samples were much lower (1 - 40 ng/L), indicating very high enrichment factors for PFAS in seafoam.Two measurement campaigns for PFAS in ambient air, at two beach locations, have found concentrations below provisionary ambient air quality standards for PFAS. However, they were significantly higher than concentrations measured in urban air in the Antwerp (B) area and in a non-suspect background location. PFAS profiles in air samples were comparable to those found in seafoam.Beach sand quality has been examined at three locations with composite samples of the upper 20 cm of the beaches where seafoam and sea water have been sampled. Soil samples were collected from flooded parts of the beach and non-flooded areas. Almost all samples had relatively low concentrations of target PFAS (0,3 - 6,2 μg/kg total PFAS, max 5,4 μg/kg PFOS).
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10:00 - 10:10
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Demonstration of Remediation technologies for PFAS via KIS-projects
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Leen Bastiaens (KIS, Belgium)
KIS (Knowledge Centre Innovative remediation Solutions) is a network-like organization that brings together authorities, companies and research institutes to jointly spur innovation and cooperation to tackle compounds of concern like PFAS. KIS vzw was established in October 2023 by the Flemish Government to centralise the knowledge and experience gathered by various stakeholders, facilitate knowledge exchange and stimulate collaboration.
To meet with these objectives, 2 calls for proposals were launched by KIS in collaboration with OVAM in 2024. Eight demonstration projects focusing on remediation and purification of PFAS from the environment (Soil, groundwater and wastewater) were granted to multidisciplinary consortia of KIS-members: INSERT, PIGGS, p-FRESCO, InSuFix, HEMP4PFAS, MembRIX, IPS@TACK and INJANT. Technologies demonstrated comprise stabilization, foam fractionation, destruction by non-thermal plasma, uptake by plants, membrane filtration and ion exchange (with regeneration of the resins).
The general scope of these KIS-projects will be presented.
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10:10 - 10:20
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Synergistic Remediation Technologies: A Pathway to Sustainable Remediation
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Jan Haemers (Haemers Technologies, Belgium)
IntroductionThermal desorption is a cornerstone of sustainable soil remediation strategies. By effectively targeting source zones or concentrated areas of contamination, thermal desorption enables the efficient removal of hazardous substances. When combined with other complementary techniques such as soil washing, phytoremediation, in situ oxidation, and bioremediation, thermal desorption forms the core of a versatile and comprehensive approach to environmental contamination management.Key Technologies in the StrategyThe integration of thermal desorption with other remediation technologies provides a multifaceted solution. Soil washing, for instance, is an effective technique to concentrate contaminants like per- and polyfluoroalkyl substances (PFAS) in fine soil particles. This process substantially reduces the volume of soil that requires treatment, making the overall remediation process more cost-effective and less resource-intensive. After soil washing, the concentrated contaminated material can be treated using thermal desorption at high temperatures, breaking down contaminants and neutralizing them at the molecular level.Thermal desorption, followed by in situ chemical oxidation (ISCO), offers an integrated approach to soil remediation. After thermal desorption concentrates and removes contaminants from source zones, ISCO can be applied to treat saturated or dispersed areas. The heat from the thermal treatment activates chemical oxidants, enhancing their effectiveness and accelerating the degradation of pollutants. This combination maximizes the efficiency of the treatment process, ensuring comprehensive remediation of contaminated soils.Sustainability of the combined remediation technologiesThe combination of thermal desorption and other technologies, such as ISCO or soil washing, enhances the overall sustainability of the remediation process. From a temporal perspective, this integrated approach ensures that the contamination is completely treated, reducing the likelihood of future remediation needs. Financially, using multiple techniques can optimize costs by efficiently targeting different contamination levels, minimizing the volume of soil that requires intensive treatment. Societally, this strategy often leads to fewer nuisances, as it addresses the contamination more effectively and in a shorter timeframe, which benefits local communities. Additionally, it fosters collaboration across various fields of expertise, creating a more holistic and sustainable approach to environmental management.
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10:20 - 10:30
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Managing invasive biotic pollutants: A strategic action plan for Asian Knotweed
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Tom Pinceel and Lena Vanderhaegen (Witteveen+Bos, Belgium)
Biotic pollutants, such as invasive plant species, are increasingly recognised as novel sources for diffuse soil pollution. Since they often impact extensive areas, classic remediation techniques are typically unsuitable or extremely costly. We present an evaluation of promising alternative risk management strategies, through an extensive cost-benefit analysis and compile a strategic action plan for dealing with diffuse biotic pollutants. Ultimately we aim to fuel policy recommendations and help build a realistic framework for treating this type of emerging pollution.As a specific case study we tackle the problem of the ‘Asian knotweed’. This plant species is among the most distributed and visible biotic pollutants in our environment and causes enormous damage to both natural ecosystems and infrastructure across the EU. Despite its socio-economic significance, adequate treatment methods are lacking and the legal framework to deal with knotweed-associated soil pollution is deficient. Therefore, many studies are currently undertaken to devise treatment methods for infected areas and policy recommendations are called for. Here, we perform an integrative exercise and distil a generic action plan from the state-of-the art.
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10:30 - 11:00
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Feedback from the workshop
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11:00 - 11:30
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Coffee break
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11:30 - 11:50
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Shaping Tomorrow's Soil Health: A Focus on Prioritizing Contaminants of Emerging Concern (CECs) in soil and groundwater Investigations
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Antoine Zanutel (Arcadis, Belgium)
Following the global PFAS concerns, the Walloon Minister of the Environment commissioned a study to define recommendations for investigations and analyses of emerging contaminants for authorized soil experts in Wallonia, Belgium. Emerging contaminants are often overlooked in soil and groundwater studies due to a lack of knowledge among soil experts.First, the Walloon Public Service (SPW) conducted a review of all CECs to focus on specific families of contaminants. The selection was based on existing knowledge and the need to address these compounds in local soil and groundwater investigations. The following groups of emerging contaminants (CECs) were selected by the SPW: PCBs, dioxins/furans, phthalates, flame retardants, bisphenols, chlorobenzenes, chloronaphthalenes (CNPs), short-chain chlorinated kerosenes (SCCPs) and hexachlorobutadiene (HCBD).Then, the phase 1 of the project involves the identification of all substances from the selected CECs, the pre-selection of relevant substances, literature research on physico-chemical and toxicological parameters, high-risk historical/current activities related to the substances, and analytical methods. A methodology has been formulated to gather all necessary information. Literature research has been conducted on 219 preselected substances.Phase 2 focused on developing a scoring system to prioritize substances and identify those likely to cause soil and groundwater pollution. A methodology was created to assign a score to each substance to classify and select the most relevant substances to investigate in soil investigation studies.In conclusion, the study emphasizes the importance of identifying and prioritizing emerging contaminants to improve risk understanding and guide decision-making. The results will support targeted investigation strategies of CEC.The presentation will cover a variety of emerging contaminants included in the study, along with details on the methodology and scoring system used to inventory and prioritize pertinent CECs in soil and groundwater investigations.
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11:50 - 12:10
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Diffuse soil contamination of emerging contaminants along highways in Flanders – Exploratory measurement campaign
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Dorien Gorteman ( Arcadis Belgium)
Purpose of StudyThe study aims to investigate diffuse soil contamination of emerging contaminants (EC) along highways in Flanders. The project is commissioned by the Public Waste Agency of Flanders (OVAM) to identify challenges posed by the extensive vehicular traffic in the region.MethodologyA phased approach was applied. The project began with a preliminary literature review to establish a foundational understanding of the contaminants involved.Ten locations with a high volume of traffic (both freight and passenger transport) were selected. Samples were taken at 1, 5 and 10 meter distance from the road pavement. If a ditch was present, it was also sampled.The research methodology involves conducting targeted and suspect screening (non-targeted) measurement campaigns to assess the extent of diffuse contamination of EC caused by transport activities and road materials.Summary of Findings/ResultsUsing target analysis, the presence microplastics, rubbers, bromated flame retardants, phthalates, bisphenol A, glyphosate and other pesticides (e.g. DDT) in the soil of roadside verges along highways has been quantifiably proven.Using DART-MS and LC-MS (suspect screening), the presence of phthalates, thiazoles/triazoles, PPDs (e.g. 6PPD), phenols, other additives (e.g. DPG) and pesticides (e.g. fipronil), pharmaceutical products, glycols, VOCl and PFAS in the soil of roadsideverges along highways has been qualitatively proven.ConclusionsEC are present in in the soil of roadside verges along highways. Some of the anticipated results can be linked based on their use to vehicular traffic and the highway infrastructure (e.g. phthalates, rubber). Suspect screening qualitatively proved the presence of other EC.However, suspect screening cannot be used to make a statement about the spatial extent of the problem and influence zones.SignificanceThis study represents a proactive step towards addressing diffuse soil contamination of EC in Flanders, providing valuable insights into the relationship between transportation activities and environmental pollution. The outcomes of this study are expected to inform future policy interventions, management strategies, and risk assessment frameworks to safeguard the quality of soil and protect ecological systems in the region.
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12:10 - 12:30
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Leveraging uncertainty frameworks for groundwater impact assessment in Australia for contaminant risk assessment in Europe
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Luk Peeters (VITO, Belgium)
Over the past decade, Australian regulatory frameworks have embedded uncertainty quantification as a standard component of groundwater impact assessments. This requirement has catalyzed widespread integration of uncertainty analysis across both academic and consultancy groundwater modelling practices. Regulatory guidance emphasizes the critical role of uncertainty analysis in risk assessments for large-scale infrastructure developments — such as redeveloping brown fields, major infrastructure works? mining and unconventional gas extraction—by requiring a transparent linkage between development activities, hydrogeological pathways, and potential receptor impacts.This review synthesizes Australian guidance and practical implementation to identify transferable insights for contaminant risk assessment within European contexts. Key focus areas include methodological complexity, decision-making integration, and communication of uncertainty.Findings indicate that:- Uncertainty analysis is technically viable, with mature software tools enabling its implementation.
- Not all sources of uncertainty are quantifiable; uncertainty from choices and assumptions in conceptualization and scenarios must be explicitly recognized, and assumptions thoroughly documented and justified.
- Clearly defining quantities of interest in function of a source – receptor pathway remains challenging.
Environmental regulators in Europe are increasingly challenged by the complex nature of contaminant risk management. The Australian experience underscores that situating this issue within a framework that explicitly acknowledges uncertainties and gaps in current scientific understanding empowers decision-makers to adopt transparent, evidence-informed, and context-sensitive approaches to environmental risk governance.
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12:30 - 13:30
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Lunch
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13:30 - 13:50
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Colloidal Activated Carbon Approaches in PFAS Remediation: Case Studies of Source Zone Stabilization and Plume Migration Control
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Kris Maerten (Regenesis, Belgium)
In situ remediation using colloidal activated carbon (CAC) provides a sustainable approach for PFAS stabilization and attenuation, forming sorptive treatment zones or barriers that reduce contaminant flux to prevent further impact to downgradient receptors without generating secondary waste or requiring long-term infrastructure and energy use. Presented here are field-scale applications that demonstrate CAC’s performance under distinct hydrogeological and PFAS-loading conditions.At a Belgian textile facility, PFAS (6:2, 8:2, 10:2 FTS and PFOA) were concentrated in a loamy clay capillary zone overlying a permeable sand aquifer. SourceStop® CAC was injected via low-pressure rotary auger to ensure continuous vertical coverage. Nested well monitoring revealed >89% PFAS reduction within one month and >99% by five months, validating source mass stabilization and flux control.At Örnsköldsvik Airport*, Sweden, PFOS concentrations reached 200,000ng/L in a shallow sand aquifer, with a migrating plume threatening a natural spring 100m downgradient. The site was designated by the Swedish Geotechnical Institute and Geological Survey of Sweden as an ideal demonstration location for CAC-based PFAS containment. A 70m wide in situ barrier using PlumeStop® CAC was constructed across the plume core. High-resolution stratigraphic data guided interval-specific injection from the water table to an underlying clay confining layer. Despite sub-zero field conditions, over 160 groundwater samples confirmed >95% PFAS reduction in the barrier within one month. After six months, average reductions reached 99.6% in barrier wells and up to 99.8% downgradient. The impacted natural spring showed a 99.3% concentration decrease, confirming progressive displacement of contaminated water.These results confirm CAC’s efficacy in complex hydrogeologic settings and its suitability for both source and plume applications, with broad-based applicability to reduce environmental and public health risks. Ongoing monitoring continues to support the long-term stability and performance of CAC treatment zones under field conditions. Reference will also be made to third-party papers that corroborate field performance and provide additional data for further study.
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13:50 - 14:10
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Decoding PFAS Behavior in soils: Evidence from three PARC case studies on leaching, source identification and spatial distribution
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Ward Swinnen (VITO, Belgium) and Laetitia Six (OVAM, Belgium)
Per- and polyfluoroalkyl substances (PFAS) are a critical environmental health concern due to their persistence, toxicity, and complex behavior in soil. Challenges remain in understanding their distribution and linking observed contamination to specific sources. To address these gaps, three case studies, under the EU PARC project (www.eu-parc.eu) were conducted In Flanders, Belgium. Objectives include examining how molecular structure influence PFAS mobility and exploring the use of non-target methods to obtain PFAS fingerprints for source identifications. This work aims to enhance our understanding of PFAS pathways and support more effective remediation.Case Studies:- Experimental determination of Kd values in 25 Flemish soils using 24-hour batch tests.
- Spatial distribution analysis at a former paper manufacturing site.
- Non-target PFAS screening of soil and groundwater at high-risk locations.
Materials & Methods:Samples were collected from soil, groundwater, and sediments. A variety of analytical techniques wereused: target analysis, ultra-short chain PFAS detection, suspect/non-target screening (e.g., DART-MS, NTA), total PFAS, extractable/adsorbable organofluorine (EOF/AOF), and oxidizable precursor assays (TOPA).Results and Discussion:Case 1: The first comprehensive Kd and Koc dataset for Flemish soils includes 38 target and 2 ultra-short chain PFAS. Chain-length-dependent sorpon was observed, with lower values for ultra-short chains. These findings support PFAS transport modeling and remediation planning.Case 2: PFAS concentrations decreased with depth and distance from the former site. Short-chain PFAS (e.g., PFBA, PFPeA, PFHxA) were found farther from the source, while long-chain PFAS (e.g., PFOS, PFOA) were more abundant in deeper groundwater. Target and non-target analyses showed consistent PFAS profiles, indicating limited added value of NTA in this context.Case 3: NTA screening at sites with different industrial histories (e.g., paper, textiles, firefighting) revealed distinct PFAS fingerprints. While site origin could not always be uniquely identified, consistent fingerprints within sites allowed source correlation. This approach enhances source attribution and supports targeted remediation.
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14:10 - 14:30
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Turning the Tide: PFAS Challenges and Europe’s Water Resilience Strategy
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Dirk Nuyens (ERM Belgium and the Netherlands)
PFAS (per- and polyfluoroalkyl substances), known as “forever chemicals,” are now ubiquitous across Europe’s environment. They are persistent, resisting degradation and accumulating in water, soil, sediments and living organisms.PFAS pollution stems not only from industrial sites but also from diffuse sources such as certain pesticides, land-applied biosolids, and atmospheric breakdown of fluorinated gases into ultrashort PFAS. These pathways spread contamination over large areas.Consequently, even background PFAS levels in groundwater are elevated, and PFAS compounds are frequently detected in drinking water and (protected) water reserves. This low-dose exposure raises potential health concerns and has prompted stricter monitoring.
High-concentration PFAS hotspots occur near manufacturing facilities and sites of heavy firefighting foam (AFFF) use (incl. fire training). Nearby communities could face increased exposure, making remediation an urgent priority.
Fully remediating PFAS is daunting, with cleanup costs projected in the tens of billions of euros, or potentially even higher.Proportional, risk-based solutions are essential. Interventions should be prioritized for maximum health benefit per cost, while ensuring fair cost-sharing to maintain public trust in water safety.European regulators are tightening PFAS limits (e.g., in drinking water) and proposing an EU-wide phase-out of most PFAS uses.These measures align with Europe’s water resilience strategy (EWRS) to safeguard water resources from pollution. Effective PFAS control is pivotal for long-term water supply security: accelerated by climate change and water drought it is a real dual challenge to cope with future availability of quality water for human livelihood and industrial activities.
Industries such as food, beverage, and agriculture face rising compliance costs, but also opportunities to innovate toward PFAS-free inputs. The challenge is no longer isolated to individual corporations — PFAS liability is emerging as a systemic risk across industrial value chains, with growing scrutiny from financial institutions and investors.A critical inflection point is approaching: should we continue capturing PFAS or invest in destruction technologies? This presentation calls for accelerated development of PFAS elimination methods, pragmatic regulation, and cross-sector collaboration — vital steps to mitigate risks and secure Europe’s water future.
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14:30 - 15:00
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Closing remarks
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15:00 - 16:00
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Coffee and networking
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