Recent research on PFAS has raised concerns and led to stricter regulation in many countries. PFAS combines aqueous mobility, extreme recalcitrance and adverse health effects at very low concentrations. This requires immediate actions to reduce their release and spreading, better understand their transport and associated risks, and to remove them from the environment. The unique properties of PFAS also pose many additional challenges for groundwater management, risk assessment and remediation. Many processes in both the groundwater and vadose zones need to be better understood and there is an urgent need for improved remediation and mitigation methods. Field testing and upscaling findings from laboratory batch and column testing conducted under idealized soil conditions to natural conditions at field sites is critical.
This interdisciplinary session fosters the exchange among scientists from hydrogeology, microbiology, ecotoxicology, engineering, and analytical chemistry in order to provide a general picture of the occurrence and fate of natural and engineered particles and PFAS in aquatic and terrestrial systems. The presented papers will provide better process understanding through laboratory and field research, modeling, and site characterization to address new challenges and solutions associated with contamination of the soil-groundwater system by PFAS and particles as well as unsolved challenges related to other emerging or traditional contaminants.
Orals: Thu, 7 May, 14:00–17:50 | Room 2.44
Advanced (nano)materials have and will play a key role in environmental and energy transitions by enabling innovative solutions in water treatment, agriculture, energy production, electronics, and building efficiency. Past technological developments have taught us that long-term sustainability also depends on the accurate assessment of environmental and health risks. For advanced (nano)materials, whose properties are strongly influenced by size, shape, surface chemistry, and structural defects, risk assessment must explicitly account for realistic exposure scenarios and material transformations throughout their life cycle. In this context, mesocosm experiments represent a powerful approach to bridge the gap between laboratory studies and complex real-world environments.
This presentation highlights how aquatic mesocosms can be used to assess exposure, fate, and the ecological impacts of advanced (nano)materials and nano-enabled products under environmentally relevant conditions, thereby supporting Safe- and Sustainable-by-Design strategies. We will present several case studies involving pristine nanomaterials, nano-enabled products, and incidental nanoparticles generated during the advanced (nano)materials use phase or end-of-life. They include tungsten-based nanomaterials used for energy applications, tritiated stainless steel (nano)particles potentially released during nuclear dismantling scenarios, silver nanowires embedded in printed paper electronics, and mixed-metal oxide nanoparticles incorporated into infrared-reflective outdoor paints. Results from these mesocosm studies have revealed complex biogeochemical transformations such as dissolution, redox reactions, polymerization, and matrix-driven partitioning, which in turn drive the bioavailability, trophic transfer, and biological responses to the advanced (nano)materials.
Finally, we will discuss how mesocosm-based datasets support environmental risk assessment in relevant exposure conditions and guide material innovation toward safer and more sustainable outcomes. Their integration into collaborative platforms and decision-support tools enhances Safe- and Sustainable-by-Design implementation across technology readiness levels.
How to cite: Auffan, M., Carboni, A., Ouaksel, A., Slomberg, D., and Rose, J.: Exposure and impacts of advanced (nano)materials : using aquatic mesocosms to evaluate and minimize environmental risks, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17307, https://doi.org/10.5194/egusphere-egu26-17307, 2026.
The increasing recognition of PFAS contamination in soil and groundwater necessitates effective and sustainable remediation strategies. Steam-activated biochars (SA-BCs), derived from renewable feedstocks (e.g., agricultural waste), are gaining attention as alternatives to conventional activated carbons for PFAS sorption due to their lower environmental footprint. However, studies on the sorption of PFAS to SA-BCs under field-realistic flow-through conditions remain scarce. Rapid small-scale column tests (RSSCTs) provide a versatile tool to estimate the performance of sorbents in full-scale systems (e.g., fixed-bed filter) in the lab. Yet, the influence of experimental uncertainties (e.g., varying flow rates) on the resulting breakthrough curves is often not discussed. Therefore, the aim of this study was twofold: (i) to investigate the performance of a SA-BC for the immobilization of PFAS in soil under flow-through conditions and (ii) to estimate the effect of experimental uncertainties on the fitting results.
Sorption of seven C4 to C8 per- and polyfluoroalkyl acids in synthetic groundwater to loamy sand amended with 0.5% SA-BC was investigated in small-scale columns (4cm x 1cm). Breakthrough curves were analysed using the ‘Ogata-Banks’ solution for the 1D ADE, including a Monte Carlo framework to assess the influence of experimental/ analytical uncertainties for flow rate, porosity and measured PFAS concentrations on the results.
Compared to untreated soil blanks, in which immediate breakthrough was observed for most compounds, the addition of 0.5% SA-BC led to a significant retardation with retardation factors of ~10 for PFBA to ~1500 for PFOS – with the elution order correlating with chain-length and functional group. Monte Carlo simulations for PFOS with relative uncertainties of 5% for flow rate, porosity and PFOS concentrations resulted in retardation factors of 854 to 3420 with a mean ± one standard deviation of 1545 ± 333. Corresponding breakthrough times for 50% PFOS range from 678 to 861 min, indicating that estimation of retardation and consequently breakthrough times based on single experiments could lead to substantial underestimation.
While our data highlight the potential of SA-BC for in-situ immobilization of PFAS in contaminated soils, they also emphasize the importance of considering experimental uncertainties. Ongoing work is focused on the influence of environmental factors, such as matrix composition, on reactive transport. Together, these advances will support a robust, uncertainty-integrated framework for getting deeper insights into the interaction of PFAS with SA-BCs and estimating PFAS immobilization in the field und varying conditions.
How to cite: Martin, P. R., Herbst, A., and Hofmann, T.: Estimating PFAS Immobilization by Activated Biochars: Insights from Rapid Small-Scale Column Tests and Uncertainty Modelling , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12423, https://doi.org/10.5194/egusphere-egu26-12423, 2026.
Per- and Polyfluoroalkyl substances (PFAS), also known as “forever chemicals” pose significant environmental and health risks due to their persistence, mobility, and resistance to conventional water treatment methods. PFAS entirely contaminates the earth, but monitoring data are often scarce, limited, or hard to access. The strong C-F (536 kJ/mole) bonds allow them to accumulate in the environment, wildlife, and human bodies, leading to potential health risks such as cholesterol, immune system suppression, thyroid disease, cancer, and other developmental issues. PFAS contamination in water bodies, landfill leachates, soils, and the atmosphere is a growing concern globally. Previous studies in India detected PFAS in surface water (up to 23.1 ng/L), tap water (10-100 ng/L), and in biotas like fish, shrimp, and dolphins (0.093-83.9 ng/g), human breast milk. Treatment of PFAS-contaminated water, soil and wastewater is essential to ensure the destruction of persistent chemicals harmful to the surrounding environment. Traditional treatment technologies, such as biological treatment processes, chemical processes such as coagulation and chlorination, and physical processes such as sand filtration, cannot eliminate these pollutants. Membrane technologies particularly nanofiltration (NF), reverse osmosis (RO), membrane distillation (MD) offer an advanced and sustainable solution for removing persistent PFAS from contaminated water, landfill leachates, and industrial effluents. Processes such as NF, RO, MD, provide high rejection of both long and short chain PFAS, enabling effective cleanup where conventional treatments fail. Their selectivity, efficiency and compatibility with hybrid systems make membranes a powerful tool for mitigating PFAS across diverse environmental systems. This study highlights the importance of advanced membrane technologies for the remediation of PFAS contaminated water.
How to cite: Chanu, L. R. and Deka, B. J.: Membrane technologies for the effective removal of Per- and Polyfluoroalkyl substances from contaminated water, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-983, https://doi.org/10.5194/egusphere-egu26-983, 2026.
Per- and polyfluoroalkyl substances (PFAS) are increasingly detected in groundwater co-contaminated with conventional pollutants, such as hydrocarbons, heavy metals and chlorinated solvents. Such mixtures are challenging for groundwater treatment because co-contaminants can strongly compete with PFAS for sorption sites, thereby reducing sorbent performance. Moreover, while ion-exchange resins and activated carbon remain the industry standards for PFAS removal, innovative sorbents may offer new pathways for improved PFAS removal. Understanding the sorption behaviour of PFAS in the presence of co-contaminants is essential for designing effective groundwater treatment strategies for complex contaminated sites.
In this study we investigate the performance of 17 sorbents for PFAS removal in co-contaminated groundwater. The sorbents included 6 industry standards, ion exchange resins (n=3), activated carbon (n=3), as well as 11 innovative sorbents: surface-modified bentonites (n=2), surface-modified zeolites (n=3), proteins (n=3), a cyclodextrin (n=1), an iron-oxide based material (n=1) and an activated carbon/aluminum hydroxide-based material (n=1). The groundwater tested was pre-treated to remove volatile aromatic hydrocarbons but contained high dissolved organic carbon (20 mg/L) and had elevated ionic strength (0.017 M), along with residual phenols (phenol index: 7.3 µg/L) and mineral oil (C10–C40: 60 µg/L), concentrations typical for residually contaminated groundwater. PFAS concentrations were dominated by PFOA (~830 ng/L) and PFOS (~100 ng/L), with additional short-chain PFAS, e.g. PFBA (24 ng/L) and PFBS (18 ng/L).
All sorbents were initially screened at two sorbent concentrations (0.1 and 1.0 mg/L) and the six best performing sorbents were tested on a range of eight sorbent concentrations (0.01-2.0 mg/L). Finally, column experiments were performed with three sorbents to simulate full-scale treatment plant flow conditions. Despite residual co-contamination, several sorbents achieved high (>96%) PFAS removal at 1.0 g/L. Notably, at low sorbent concentrations albumin, an egg-based protein, showed PFOA removal comparable to activated carbon at the same sorbent concentration (~30%), whereas casein, a bovine milk-based protein, was contaminated and caused PFOA concentrations in the groundwater to increase to 2500 ng/L. Sorption capacities (Langmuir qmax) ranged from 1.24 to 10.45 µg/g, with ion-exchange resins highest. All sorbents were sensitive to interfering co-contaminants, which was especially apparent at low sorbent concentrations (10-50 mg/L). Overall, this study highlights that the presence of co-contaminants can substantially interfere with the sorption of PFAS in groundwater treatment and underscores the need for sorbents capable of maintaining high PFAS removal efficiencies under the complex chemical conditions typical of co-contaminated groundwater.
How to cite: Hockin, A., van der Grift, B., Siegers, W., van Kuik, T., Zech, A., and van Leeuwen, J.: When Co-Contaminants Compete: Limits of PFAS sorption in mixed-contaminant groundwater, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1679, https://doi.org/10.5194/egusphere-egu26-1679, 2026.
Water contamination is a growing global concern, particularly due to the presence of per- and polyfluoroalkyl substances (PFAS) in drinking water, surface water, groundwater, wastewater, and sludge. These persistent pollutants pose significant health risks to humans and animals by accumulating in the body and affecting the immune system and liver. To address the emerging challenge of PFAS contamination, Granular Activated Carbon (GAC) is widely used as an adsorbent for PFAS removal in water and wastewater treatment plants. However, once saturated, it either requires additional GAC for continued use, or regeneration through processes such as chemical desorption that often produce highly concentrated secondary waste streams. To move beyond capture and address these limitations, advanced destructive treatment technologies are needed. A promising approach involves integrating GAC as a conductive material for use within electrochemical systems. This hybrid method not only retains GAC’s high adsorption capacity but also enables in situ degradation of PFAS. Despite its potential, the electrooxidation method for PFAS degradation and defluorination, particularly with GAC as an anode, remains underexplored.
Initially, electro-oxidation using GAC alone showed limited effectiveness in the degradation and defluorination of various PFAS. In addition, PFAS adsorbed onto GAC were found to undergo minimal degradation when treated with chemical oxidants such as peroxydisulfate (PDS). However, experimental results demonstrate that incorporating PDS as a reactive oxidative species during electro-oxidation with a GAC anode enhances both the degradation and defluorination of a wide range of PFAS, including linear and branched, as well as saturated and unsaturated compounds, compared to systems operated without reactive oxidative species. These findings highlight the potential of GAC-based electrochemical oxidation as an innovative and effective approach for remediating diverse PFAS classes. This method reduces the need for frequent GAC replacement by enabling in situ degradation and defluorination of adsorbed PFAS, thereby enhancing both treatment efficiency and sustainability of water treatment systems. Furthermore, the widespread commercial use of GAC in existing water treatment infrastructure supports the potential for scaling up this remediation approach to real-world applications.
How to cite: Alimohammadi, V., He, C., Sun, J., O’Carroll, D., and Manefield, M.: Enhanced PFAS Degradation by Electro-Oxidation Using Granular Activated Carbon Anodes: Performance Improvement and Scale-Up Potential, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3621, https://doi.org/10.5194/egusphere-egu26-3621, 2026.
Abstract
Per- and polyfluoroalkyl substances (PFAS) are widespread groundwater contaminants that are increasingly causing concern and prompting regulatory action due to their extreme persistence, mobility, limited biodegradability, and harmful properties. Perfluorinated compounds in particular, such as perfluorooctanoic acid (PFOA), one of the most common and most studied representatives of this class of PFAS, also show high resistance to chemical degradation and pose particular challenges for conventional remediation methods. Current treatment approaches are therefore based either on adsorptive removal from water without destruction or on energy-intensive processes that allow the molecules to be destroyed. Therefore, new low-energy methods are urgently needed. Integrated systems that combine pre-enrichment with efficient degradation under environmentally relevant conditions are therefore the focus of recent research.
In this study, FeS2-zeolite composites were developed by immobilizing crystalline pyrite on a hydrophobic BEA-35 zeolite to achieve coupled in-situ adsorption and peroxydisulfate (PS) activation for PFOA degradation. FeS2-BEA35 facilitated hydrophobic enrichment of PFOA within its porous structure with a KD value of 1.8 × 104 L/kg at a cfree of around 50 µg/L. The study on the mechanism illustrated that sulfate radicals (SO4•−) were predominantly generated through surface-mediated homolytic PS cleavage on the FeS2-BEA35 surface, serving as the dominant species for PFOA degradation. Alongside sulfate radicals, the results showed the involvement of previously unrecognized FeIV=O2+ species, generated by the oxidation of Fe(OH)(H2O)52+-PFOA complex by SO4•−. The FeIV=O2+ species acted as a secondary reactive species capable of abstracting electrons from the coordinated PFOA, thereby promoting decarboxylation and C-C bond cleavage. Although coexisting inorganic ions and natural organic matter reduced adsorption and degradation rates of PFOA, yet FeS2-BEA35 still maintained strong affinity and reactivity. Fixed-bed column experiments started with an influent PFOA of 1 mg/L, designed to approximate continuous treatment conditions, demonstrated a high PFOA adsorption capacity of about 1.2 × 103 mg/kg at a cfree of around 60 µg/L and sustained over 70 % removal efficiency under cyclic oxidation with low Fe leaching. The efficient PS utilization also confirmed dominant heterogeneous activation and excellent catalyst stability.
Therefore, FeS2-BEA35 integrates efficient adsorption and durable catalytic reactivity, offering a promising platform for continuous perfluorocarboxylic contaminant remediation through interfacial enrichment and surface-mediated PS cleavage.
How to cite: Guo, P., Sühnholz, S., and Mackenzie, K.: Coupling Adsorption and Persulfate Oxidation Using FeS2-Zeolite for Efficient PFOA Removal, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7118, https://doi.org/10.5194/egusphere-egu26-7118, 2026.
Per- and polyfluoroalkyl substances (PFAS), “forever chemicals”, are persistent, ubiquitous, and toxic. They pose a threat to both human health and the environment, therefore efficient remediation strategies are urgently needed. One possible remediation technology to treat contaminated soil is thermal desorption. However, the transformation mechanisms and products created during thermal desorption have not been fully assessed yet. Precursor substances, which transform to persistent PFAS substances in the environment, are of particular interest.
This study investigates the thermal desorption and transformation of PFAS. We conducted multiple thermal desorption experiments with artificially contaminated PFAS-sand in a stainless-steel column, which was heated by a heating rod and mantle. The maximum temperature reached in the column is 500 °C. We hypothesize that during this experiment the PFAS will desorb from the sand and enter the gas phase. Further, we assume that chemical transformation processes will occur, leading to products with shorter chain lengths. To understand the fate of the PFAS substances, we analyze the gas phase and the concentration of PFAS in the sand before and after the heat application. We use target and non-target approaches to identify transformed products. Furthermore, the decomposition of PFAS is examined by measuring the produced fluoride ions and evaluating the fluorine mass balance.
Our experiments showed that thermal desorption of PFAS is taking place in the regions of the column where the boiling temperatures of the individual compounds were exceeded. Depending on the substance and temperature setting used, complete removal of the spiked PFAS from the sand was achieved. By using LC-MS/MS target analysis we found multiple PFAS with shorter chain-length than the spiked substance after heating. In rare cases longer chain lengths were observed. These transformation products were mainly found in the samples taken from the gas stream. Based on these results we conclude that thermal desorption can be used as a treatment method to remove PFAS from contaminated material – however, it is essential to keep in mind that PFAS transformation products will exist in the gas phase and therefore adequate treatment of the exhaust gas is necessary. Further studies will be conducted with artificial PFAS-soil as well as with additives. By using additives, we hope to improve the mineralization rate, suppress the formation of undesired transformation products, and minimize the energy demand. With our experiments we expect to enhance the chemical process understanding of thermal desorption of PFAS, which will lead to an improved application design of this thermal treatment method.
How to cite: Burkhardt, A., Junginger, T., and Haslauer, C.: Investigation of the Transformation Products Formed During Thermal Desorption of PFAS, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10517, https://doi.org/10.5194/egusphere-egu26-10517, 2026.
Per- and polyfluoroalkyl substances (PFAS) are persistent microcontaminants originating from sources such as firefighting foams, non-stick cookware, and industrial applications. Due to their high chemical stability, PFAS are environmentally pervasive and have been associated with severe adverse health effects, including carcinogenicity.
This study investigates the remediation of PFAS from groundwater using sustainable, biomass-derived carbon materials synthesized from kraft lignin. They were synthesized under systematically varied conditions, including carbonization temperature, acid concentration, and treatment duration, to optimize their surface characteristics in order to enhance the adsorption properties. Two representative PFAS: long-chain Perfluorononanoic acid (PFNA) and Perfluorooctane sulfonate (PFOS), were selected to evaluate adsorption efficiency and material selectivity. Based on screening experiments, two optimized carbons (denoted P1 and P2) were identified for detailed removal studies. Comprehensive material characterization was performed using BET surface area analysis, SEM, XRD, XPS and FTIR to elucidate porosity, surface morphology, crystallinity and functional group chemistry. Adsorption experiments demonstrated high removal efficiencies. For P1, PFNA removal reached 97.5% at 25 ppm and 96.7% at 50 ppm, while PFOS removal was 89% and 85.7% at the respective concentrations. P2 exhibited superior performance, achieving 96% (25 ppm) and 98% (50 ppm) removal for PFNA, and 98% (25 ppm) and 98.8% (50 ppm) for PFOS. Overall, removal efficiencies exceeding 90% were achieved for both long-chain PFAS, with enhanced performance of P2 attributed to its higher phosphorus doping. Adsorption isotherm analysis showed that the Langmuir-Freundlich model provided the best fit, indicating heterogeneous surface adsorption and multilayer uptake. Kinetic studies revealed rapid adsorption within the first 60–90 minutes, indicating fast adsorption kinetics and efficient uptake of contaminant molecules onto the adsorbent surfaces. Subsequently, the synthesized carbons were investigated under dynamic adsorption conditions through continuous-flow column studies to evaluate their performance for the treatment of PFAS contaminated groundwater. In conclusion, lignin-derived, heteroatom-doped carbons demonstrate excellent potential for the efficient removal of long-chain PFAS from groundwater. The use of a renewable biomass precursor enhances the sustainability of the process, while the high removal efficiencies and favourable kinetics highlight its potential for application at contaminated sites.
Acknowledgments. This work was supported by the Wallenberg Initiative Materials Science for Sustainability (WISE), funded by the Knut and Alice Wallenberg Foundation. Oleg Tkachenko gratefully acknowledges support from the Olle Engkvist Foundation for the scholarship (235-0413).
How to cite: S. Raj, S., Tkachenko, O., Nikolaichuk, A., Fagerlund, F., and M. Budnyak, T.: Mesoporous and P-doped Kraft Lignin-derived biocarbon for PFAS removal, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19433, https://doi.org/10.5194/egusphere-egu26-19433, 2026.
Transport of hydrophobic nanoparticles in porous media is of growing interest in relation to the presence of nanoplastics and engineered NPs in the subsurface, where both hydrophobic collector surfaces and high salt concentrations may be simultaneously present by accident or design. This study investigates the effects of NP input concentration, surface wettability, and salt valence on the transport and deposition of model hydrophobic ethyl cellulose (EC) NPs in 2D hydrophilic and hydrophobic microfluidic networks under flow conditions representative of subsurface environments. Uniform porous geometries and low hydrodynamic dispersion enhance NP residence time, promoting aggregation and irreversible retention, particularly in immobile zones. Our results show that higher NP concentrations and the presence of divalent cations (Ca²⁺) result in fractal aggregate formation, permeability loss, and formation of secondary porosity, altering flow paths and elution behavior. Direct porous medium visualization during and after experiments reveals transient flocculation, post-flush release, and pore structure changes such as pore throat occlusion and dead-end zone accumulation. Surface wettability further modulates transport; hydrophobic collectors enable irreversible attachment of mostly single particles via hydrophobic interactions. Fluorescence imaging, extended DLVO theoretical calculations, particle remobilization and permeability measurements corroborate observations of nanoparticle elution, showing that the effect on NP and aggregate deposition of surface hydrophobicity outweighs that of monovalent salt, whereas divalent salt accelerates and promotes irreversible deposition. Traditional interpretation of breakthrough curves does not resolve key microscale retention mechanisms under varying physicochemical conditions. In the presence of hydrophobic attraction between particles and collector surfaces, coagulation induced by high ionic strength results in complex interactions that shape transport, aggregation, and retention of hydrophobic NPs in porous media. These findings offer critical insights into the fate of hydrophobic NPs in subsurface environments for risk assessment and design of nanoremediation interventions in the form of injectable permeable adsorptive barriers.
How to cite: Ioannidis, M. and Rahham, Y.: Transport and Retention of Unstable Nanoparticle Suspensions in Porous Media: Effects of Salinity and Hydrophobicity Observed in Microfluidic Pore Networks , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4661, https://doi.org/10.5194/egusphere-egu26-4661, 2026.
Each year, several thousand tons of microplastics (MPs) end up in the environment. While available techniques for the identification and quantitative characterization of microplastics are getting more elaborate, studies investigating the fate and ecotoxicological impact of MPs face a major challenge: differentiating between naturally occurring and artificial MPs once they are released into the environment. This issue can be addressed by labeling the artificial MPs; however, there is currently a lack of surrogates that combine labeling with a close resemblance to MPs found in the environment. Most studies use labeled polystyrene microspheres as surrogates, but these differ considerably from environmental MPs in terms of shape, chemical composition, and surface charge.
In this study, we aim to address this challenge by introducing electrospun microfibers as a precursor for irregularly shaped, optically labeled MPs. The labels were directly embedded into the microfibers, which were then broken down by shear-force exfoliation and ball milling, yielding irregularly shaped fibers and fragments. The resulting MPs exhibited a heterogeneous morphology much closer to that of environmental MPs than commercially available spherical MP surrogates commonly used. In addition to organic fluorophores, we introduced lanthanide-doped upconversion nanoparticles (UCNPs) as optical labels. This special class of luminophores combines excitation in the near infrared (NIR) with high photostability, multiple sharp emissions in the UV/visible and NIR ranges, and versatility in doping composition. The low abundance of lanthanides in the environment also enables the quantitative detection of UCNP-doped MPs using element-specific analytical methods. Overall, this new type of artificial MP offers exciting opportunities for biological and environmental studies.
How to cite: Baumann, S. J., Wieberneit, A. J., Triebel, H., and Baeumner, A. J.: Irregularly Shaped True-To-Life Microplastics with Embedded Optical Labels, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19542, https://doi.org/10.5194/egusphere-egu26-19542, 2026.
Active swimmers, such as microorganisms, are widespread in natural ecosystems and engineered systems. It is crucial to quantifying the effects of active swimming and gravitational settling during their transport in turbulent flows. Building on the previously established theoretical framework for open-channel flows, this study further addresses the case of circular pipes, a configuration highly common in engineering applications but is much more complicated due to the cylindrical geometry. In this case, active swimming is mainly affected by the flow shear in the radial direction, while gravitational settling acts vertically downward. This difference prevents straightforward superposition of swimmer motions in the same vertical direction as that for open channel flows, making analytical approaches challenging. We first neglect the mechanism of gravitational settling, and adopt the key dimensionless parameter α to quantify the interplay between active swimming and turbulent diffusion. The critical threshold is identified at the same order of magnitude as that for open channel flows, as α~0.1, to distinguish between an active swimming dominated- and turbulence dominated- transport. Numerical simulations using a particle tracking algorithm validate these theoretical results. The influence of gravitational settling is further incorporated by simulations combining particle tracking with Direct Numerical Simulation (DNS), revealing that gravitational settling plays a non-trivial role during transport in turbulent pipe flows, which significantly affects the spatial distribution of the swimmers.
How to cite: Li, G. and Wu, Z.: Effects of Active Swimming and Gravitational Settling on Particle Dispersion in Turbulent Pipe Flow, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11181, https://doi.org/10.5194/egusphere-egu26-11181, 2026.
Urban aquatic systems are increasingly burdened by complex mixtures of emerging contaminants whose interactions and cumulative risks are often underestimated by conventional monitoring strategies focused on individual compound classes. The co-occurrence of pesticides, per- and polyfluoroalkyl substances (PFAS), pharmaceuticals, volatile organic compounds (VOCs), and microplastics (MPs) poses significant challenges for water quality management in rapidly urbanizing and agro-industrial regions. Here, an integrated framework combining targeted and non-target analytical approaches was applied to assess emerging contaminants across surface water, groundwater, wastewater, and reservoir systems in multiple Mexican cities. Surface waters influenced by intensive agricultural and peri-urban activities exhibited the highest contaminant burdens. Pesticide concentrations ranged from 0.01 to 92 µg L⁻¹, with peak loads in agro-industrial reaches of the Pesquería basin where irrigation return flows and municipal wastewater converge. Transformation processes unified contaminant behavior along the river–reservoir continuum. The widespread detection of neonicotinoid transformation products and PFCA homologues derived from precursor degradation demonstrates that transformation sustains long-term, low-level contamination rather than eliminating parent compounds. Non-target screening expanded chemical coverage beyond predefined target lists and revealed diverse regulated and previously unmonitored VOCs, including industrial solvents and fragrance-related compounds, many showing limited removal during wastewater treatment. Within the semi-arid Presa de la Boca reservoir, MPs were ubiquitous (4–66 particles L⁻¹; median 21 particles L⁻¹). Alkaline pH (8.09–8.60), elevated temperatures (27.6–34.1 °C), and low dissolved oxygen (2.7–3.7 mg L⁻¹) promoted MP weathering and fragmentation. Small particles (<500 µm ≈ 87%), fragments (57.8%), and fibres (35.6%) dominated, while metal enrichment on MP surfaces highlighted their role as secondary vectors linking particulate and dissolved contaminant pathways. Overall, this study demonstrates that integrated target and non-target approaches are essential for resolving interconnected contaminant behavior and supporting mixture-aware monitoring, risk assessment, and management strategies.
How to cite: Kumar, M., Martínez Narváez, D. O., Gupta, P., and Dogra, K.: Revealing Hidden Interrelationships of PFAS-Pesticides-Microplastics in Urban Waters: Integrating Target and Non-Target Chemical Analyses Across Mexico, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20301, https://doi.org/10.5194/egusphere-egu26-20301, 2026.
Microplastics (MPs) are increasingly recognized as persistent contaminants in soils and groundwater systems worldwide. Polystyrene MPs are highly hydrophobic and show strong homoaggregation, which affects their mobility in porous media. Most laboratory transport studies therefore use chemical dispersants, such as Tween 20, to achieve a uniform distribution of particles during transport experiments. However, these additives coat plastic surfaces and alter plastic–soil interactions, making it difficult to assess environmentally realistic transport behavior. Here, we introduce a surfactant-free approach based on controlled radio-frequency oxygen plasma treatment to modify MP surface properties. Oxygen plasma-treated polystyrene particles (<10 μm) became fully hydrophilic, with water contact angles decreasing from 137° to 0°. This surface modification enabled the formation of stable, well-dispersed particle suspensions at loadings of 200 mg L⁻¹ without any surfactants, overcoming the strong aggregation typically observed for pristine particles. Importantly, plasma treatment did not cause bulk polymer degradation, and the particles remained physically intact without melting or fragmentation. We hypothesize that plasma-treated MPs will exhibit transport behavior distinct from both pristine hydrophobic MPs and chemically dispersed MPs. Column experiments using quartz sand will compare the mobility of untreated, surfactant-assisted, and plasma-treated polystyrene particles to evaluate whether dispersants artificially enhance MP transport by suppressing soil–particle interactions. Overall, this surfactant-free method offers a step toward supporting more accurate environmental risk assessments without bias from additional surfactants.
How to cite: Lu, Y., Khaleel, R., Hassan Shanthakumar, R., Tosun, N., Rolf, M., Laermanns, H., Verma, K., Rao, L., Fischer, T., Mathur, S., and Bogner, C.: Plasma-treated polystyrene microplastics for enhanced transport studies in porous media: A surfactant-free approach, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18313, https://doi.org/10.5194/egusphere-egu26-18313, 2026.
The Himalayas are critical geographical regions, recognized for their remarkable beauty; however, plastic littering in the Himalayas is increasing exponentially due to ignorance in every matrix. Due to long-term nescience, the degradation of microplastics has been observed and found ubiquitous. Microplastics (MPs) belong to plastic particles less than 5 mm in size. The MPs are one of the critical environmental contaminant reported by various studies, such as oceans, rivers, lakes, and estuaries. Yet, their distribution in western Himalayan river systems are poorly understood. To understand this knowledge gap in research, this study provides a brief quantification, characterization, and its fate in selected western Himalayan rivers: Beas river, Parvati river, Uhl river, and Suketi river, originating from high altitude. Sediment samples were collected from 25 locations, while sampling, field images were taken to understand the source of contamination. The established protocol was performed for pre-treatment process involving sediment sieving: coarse sand (4.75 mm-2.36 mm), medium sand (2.36 mm-0.3 mm), fine sand (0.3mm-0.075mm), siltyclay (<0.075mm) and their organic digestion, and density separation for MPs. Afterward, isolated MPs were followed for visual identification, Raman spectroscopy and Fe-SEM analysis represented polymer specification and surface weathering. The results reveal notable spatial variations with highest MPs concentration 185±14 MPs/gm in Beas river followed by 182±15 MPs/gm in Suketi river due to direct waste disposal. The trend followed by MPs concentration in sediment fraction were siltyclay> fine sand> medium sand, including remote locations. All the samples resulted transparent MPs within the size range of 10-20 µm mainly belonging to PVDF (polyvinylidene fluoride), followed by PEG (polyethylene glycol), PE (polyester), and others prevailing types of MPs. The MPs was notably higher in siltyclay sediment fraction, which are easily transported from higher altitude to lower altitude. This study offers novel insights into the fate of MPs in fragile mountain ecosystems and emphasizes the role of sediments as an important reservoir influencing pollutant transport.
Keywords- Himalayas, Microplastics, Sediment fraction, Raman Spectroscopy, Fe-SEM
How to cite: Gupta, N., Parsai, Dr. T., and Kulkarni, Dr. H. V.: Investigating the Occurrence of Riverine Microplastic Pollution in Western Himalayan region, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-942, https://doi.org/10.5194/egusphere-egu26-942, 2026.
Drinking water is essential for sustaining households, industries, and agriculture, yet groundwater—the primary source across the Mahanadi Sub-Basin is increasingly burdened by human-driven pollution. This study employs FEFLOW to model the co-transport of nitrate and PFAS (per- and polyfluoroalkyl substances) over a ten-year period, marking the first integrated assessment of their linked behavior in the region. With a calibrated accuracy exceeding 90%, the model reveals that both contaminants share overlapping pathways influenced by aquifer slopes, hydraulic gradients, and pumping stresses. The simulations show that regions with intense agricultural activity and legacy waste disposal exhibit simultaneous rises in nitrate and PFAS levels, indicating common pollution sources and co-migration mechanisms. Purnokot emerges as the most impacted zone, where the convergence of these contaminants underscores the vulnerability of local aquifers. High nitrate concentrations in the eastern and southeastern sectors are driven by fertilizer inputs and landfill leachate, while PFAS plumes persist and extend due to their low sorption and high mobility—often mirroring nitrate distribution patterns. Together, these contaminants pose serious health risks, particularly for infants, pregnant women, and communities exposed to long-term PFAS accumulation. Although some wells may remain usable for irrigation with appropriate treatment, the study highlights the need for continuous monitoring, regulated chemical usage, and smarter water-management tools including sensors and real-time alert systems. Strengthening community engagement and adopting sustainable farming practices will be crucial for protecting public health and ensuring groundwater security in the future.
How to cite: Sahu, K., Chakma, S., and Rao, Y. R. S.: A Novel Approach to Contaminant Transport Modelling for Groundwater Sustainability, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1517, https://doi.org/10.5194/egusphere-egu26-1517, 2026.
Posters on site: Thu, 7 May, 10:45–12:30 | Hall A
At Örnsköldsvik aiport in northern Sweden historical firefighting training activities has resulted in a strongly contaminated hotspot with per- and polyfluoroalkyl substances (PFAS), with total concentrations exceeding 100000 ng/L in the groundwater. As part of a governmental assignment on PFAS mitigation, the Swedish Geotechnical Institute and Swedish Geological Survey have installed a large pilot-scale colloidal activated carbon (CAC) barrier intercepting the PFAS plume. Field observations show that the CAC barrier has effectively reduced PFAS mobility, with strongly reduced downstream concentrations and no notable breakthroughs detected within two years after barrier installation. To predict the long-term performance and carefully evaluate sorption processes within the barrier, controlled laboratory-scale column experiments were designed using soil from the barrier and the natural PFAS-contaminated groundwater. The spatial variation of injected carbon in the barrier has been characterized by soil coring. Soil from two representative locations with different CAC contents (0.037% and 0.103% by weight) as well as natural soil from before CAC injection were examined in flow-through column experiments monitoring the breakthrough of different PFAS. The groundwater taken from upstream the barrier contained several perfluoroalkyl carboxylic acid (PFCA), perfluoroalkyl sulfonic acids (PFSA), fluorotelomer sulfonates as well as unknown precursors indicated by total oxidizable precursor (TOP) analyses. The results provide quantitative estimates of PFAS adsorption capacity, retardation factors, competition effects and breakthrough characteristics in relation to injected CAC content. The findings can be used to estimate the breakthrough of PFAS at the field site and predict the longevity and sorption capacity of the CAC barrier. The data can further be used to refine, develop and calibrate PFAS transport models and serve as a basis to optimise the long-term effectiveness of in-situ sorbent-based remediation.
Keywords: PFAS, groundwater, contamination, remediation, activated carbon
How to cite: Fagerlund, F. and Das, M.: Predicting the long-term PFAS sorption performance in a colloidal activated carbon barrier using laboratory column experiments, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17428, https://doi.org/10.5194/egusphere-egu26-17428, 2026.
Firefighting training sites constitute common hotspots for per- and polyfluoroalkyl substances (PFAS) originating form aqueous film forming foams (AFFF) in Europe and worldwide. An example is Örnsköldsvik airport (OER) in northern Sweden, with groundwater concentrations downstream the hotspot exceeding 100,000 ng/L. To investigate how PFAS migration from these sites can be reduced, a pilot-scale colloidal activated carbon (CAC) barrier was injected at OER within a governmental assignment to the Swedish Geotechnical Institute and Swedish Geological Survey. Two years of monitoring shows that the barrier successfully has slowed PFAS migration,however, the long-term performance still remains uncertain, as PFAS breakthrough under field conditions can take decades. This study focuses on numerical modelling of PFAS transport in laboratory-scale soil columns representing CAC-embedded barrier sections from the Örnsköldsvik site, aiming to predict long-term barrier performance. A one-dimensional model was developed using MODFLOW and MT3DMS to simulate PFAS transport, incorporating both equilibrium and kinetic sorption processes. Different sorption models were tested to predict CAC adsorption behaviour and model calibration against experimental breakthrough curves. The simulation will quantify adsorption and retardation for individual PFAS compounds, assessing the influence of CAC content and sorption mechanisms on transport dynamics. By linking laboratory data to predictive modelling, this study provides a robust framework for evaluating CAC barrier efficiency, optimising in situ remediation strategies, and improving predictions of long-term PFAS behaviour in contaminated soils and groundwater.
How to cite: Das, M. and Fagerlund, F.: Model-Based Evaluation of PFAS Transport in Colloidal Activated Carbon Permeable Reactive Barriers based on Laboratory Column Studies, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14342, https://doi.org/10.5194/egusphere-egu26-14342, 2026.
Per- and polyfluoroalkyl substances (PFAS) are persistent contaminants widely detected in terrestrial systems, where their high mobility and resistance to degradation pose long-term risks to soil and groundwater resources. Although traditional adsorbents such as activated carbon are widely used for PFAS remediation, their limited regenerability often necessitates high-temperature treatment or direct incineration with high CO₂ emissions, or the use of expensive and toxic organic solvents for desorption, thereby constraining their sustainable application in environmental systems. Here, we present a novel thermo-responsive hydrogel adsorbent that enables temperature-controlled adsorption and release of PFAS, offering a new pathway for the sustainable management and remediation of PFAS.
The hydrogel was synthesized via copolymerization of N-isopropylacrylamide (NIPAM) and 2-(methacryloyloxy)ethyltrimethylammonium chloride (MTAC) and exhibits a lower critical solution temperature (LCST) of approximately 35 °C. Above the LCST, the hydrogel surface becomes hydrophobic, promoting the adsorption of long-chain PFAS including perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) through hydrophobic interactions. Below the LCST, the surface transitions to a hydrophilic state, weakening these interactions and enabling PFAS desorption. As a result, the adsorption coefficient (Kd) of the hydrogel for PFOA at 45 °C is 35-fold higher than that at 25 °C. By exploiting this reversible hydrophobic–hydrophilic transition, adsorption and desorption of long-chain PFAS can be achieved without the use of organic solvents. Lab-scale batch experiments demonstrated that approximately 80% of PFOA and PFOS could be desorbed through temperature control alone, with complete desorption achieved upon the addition of chloride ions (Cl⁻). Notably, after ten adsorption–desorption cycles, PFOS desorption efficiency remained above 80%, indicating excellent reusability.
The environmental relevance of this approach was further evaluated using rapid small-scale column tests with tap water as a proxy for natural water matrices. Through temperature modulation and the addition of 1% NaCl, 84% of PFOS and 75% of PFOA were desorbed, with enrichment factors of 32 and 15, respectively. These results demonstrate that thermo-responsive hydrogels can provide a controllable and solvent-free strategy for PFAS retention and release, offering new opportunities for sustainable remediation and management of PFAS.
How to cite: Zhang, H., Zalaria, J., and Georgi, A.: Hydrophobic–Hydrophilic Switching in Thermo-Responsive Hydrogels: A Novel Pathway for PFAS Control and Remediation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5552, https://doi.org/10.5194/egusphere-egu26-5552, 2026.
Orbitrap based Isotope Ratio MS is preferable to classical IRMS techniques for measuring PFAS compounds for a verity of reasons. The powerful new Thermo Scientific™ Orbitrap Exploris™ Isotope Solutions workflow harnesses the combination of electrospray ionization (ESI) and high-resolution accurate mass to enable the detection of isotopologues that were previously inaccessible. ESI allows ionization of PFAS directly from the solution without the necessity of converting it to a gas. ESI also has the advantage of performing “soft” ionization, which produces intact molecular ions. These intact molecules can be fragmented within the Orbitrap mass spectrometer to gain intramolecular information on site specific isotope ratios.
Here we present the analytical improvements we have developed specifically for investigating the isotopic composition and structure of PFAS. This including sample introduction to enhance the accuracy and reliability of the isotope ratio analysis, buffers, tuning and optimization of ionization and Orbitrap MS parameters, and focusing on fine-tuning of critical parameters such as AGC target and resolution to achieve optimal performance. We will also explore data acquisition strategies for acquiring high-quality data in isotope analysis, including setting up full scan and fragmentation experiments, and data processing techniques to ensure precise and accurate results.
How to cite: Pellegrini, M., Wojtal, P. K., Davidheiser-Kroll, B., Lane, C. S., and Mead, R. N.: Analytical Improvements Using Orbitrap-IRMS to Measure Solutions of Per- and Polyfluoroalkyl Substances (PFAS) for Stable Isotopic Ratios, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5235, https://doi.org/10.5194/egusphere-egu26-5235, 2026.
Per- and polyfluoroalkyl substances (PFAS) are a widespread group of pollutants. One of the more common sources of PFAS pollution in Swedish groundwater is related to firefighting and training activities using aqueous film forming foams (AFFFs). While the data available on PFAS is increasing, differences in transport characteristics between the large number of PFAS species and lack of data relating to transport of precursors give rise to significant challenges within environmental risk assessment. At a fire training site in connection to Örnsköldsvik airport, Sweden, a pilot-scale colloidal activated carbon (CAC) barrier was installed on the 23rd of November 2023, intercepting the PFAS plume and effectively ceasing downstream PFAS transport in the groundwater. The pilot-scale study is part of an ongoing governmental mission assigned to the Swedish Geotechnical Institute, in collaboration with the Geological Survey of Sweden and the Swedish Environmental Protection Agency among other governmental institutes. The contaminated site has been monitored over the span of two years, and geological and transient hydrological models have been done as groundwork to account for heterogeneity and seasonal variability in the area. The detailed monitoring of PFAS concentrations in space and time, including monthly time series for more than 50 points, in combination with the installation of the CAC barrier, allows careful observation of PFAS migration downstream the barrier.
The aim of this study is to improve our knowledge of PFAS transport and determine governing field parameters in the natural soil downstream the barrier by numerical modelling in MODFLOW/MT3D in combination with field observations. Several different PFAS are found in the groundwater and included in the modelling, as well as some target precursors. Calibration of the model allows estimation of field sorption parameters (Kd), which are critical for PFAS transport in the soil-groundwater system. Detailed total oxidizable precursor (TOP) measurements further allow analysis also of the migration and transport behaviour of unknown precursors connected to different terminal PFCAs accounting for 20 to 30% of the PFAS in the groundwater plume. The model and extensive measurements have shown real-world differences in transport parameters and precursor retardation greater than for perfluorinated PFAS.
How to cite: Zúniga Ekenberg, A., Earon, R., Berggren Kleja, D., and Fagerlund, F.: Modelling of transport of per- and polyfluoroalkyl substances in natural soil downstream a pilot-scale colloidal activated carbon barrier, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15060, https://doi.org/10.5194/egusphere-egu26-15060, 2026.
Increased military exercises, including activities conducted at military training grounds and battlefields, as well as other operations such as mining and quarrying, can release hazardous chemicals into the environment, leading to pollution. Also compounds used in explosives during the First and Second World Wars, for instance, remain widely distributed in the environment even decades after. Slovenian territory was significantly affected by military activities during both world wars; as a result, substantial quantities of unexploded and detonated munition residues persist in the environment and represent a potential source of pollution. Similar concerns regarding soil and water contamination by explosive-related chemicals have been reported in several other countries. According to the U.S. Environmental Protection Agency (EPA), lifetime exposure (assumed to be 70 years) to certain explosive compounds in drinking water should not exceed recommended health-based limits, which range from 1 to 700 µg/L depending on the specific contaminant.
The primary objective of this study is to assess the impact of military training areas in Slovenia on groundwater and drinking water resources. To achieve this, key chemical, bacteriological, and isotopic parameters were monitored.
How to cite: Koroša, A., Petrič, M., Ravbar, N., Albreht, A., Vidović, K., Prezelj, N., Cerar, S., Kutnjak, D., Gutierrez-Aguirre, I., and Poglajen, R.: Impacts of Military Activities on Groundwater Quality, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11209, https://doi.org/10.5194/egusphere-egu26-11209, 2026.
The λ-Cyhalothrin is a type II synthetic pyrethroid and a widely applied hydrophobic insecticide. Its accumulation in subsurface environments raises environmental and public health concerns due to its persistence and toxicity. Chitosan, a biodegradable polymer with notable physicochemical and adsorptive properties, is increasingly explored for environmental remediation. This study investigates the interaction and cotransport behavior of λ-cyhalothrin and colloidal chitosan in water-saturated quartz sand under static, batch and column flow conditions at 25°C. Sorption kinetics followed a pseudo-second-order model, while transport behavior was simulated using the advection–dispersion equation, incorporating two-site attachment mechanisms both linear and nonlinear, with ripening effects. The results indicate that λ-cyhalothrin undergoes chemisorption onto both chitosan and quartz sand. Cotransport experiments revealed significant bidirectional interactions: chitosan–λ-cyhalothrin aggregates enhanced chitosan retention while concurrently reducing λ-cyhalothrin attachment. These findings demonstrate that chitosan increases λ-cyhalothrin mobility in porous media, while also increasing its own immobilization through aggregate formation. The developed model effectively captured these dynamics, suggesting chitosan’s promising role as a dual-function agent for pesticide mitigation and nanoparticle delivery in groundwater remediation applications.
How to cite: Katzourakis, V., Xenou, E., Malandrakis, A., and Chrysikopoulos, C.: Interaction and Cotransport of λ-Cyhalothrin and Chitosan in Saturated Quartz Sand: Sorption Mechanisms and Remediation Implications, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2057, https://doi.org/10.5194/egusphere-egu26-2057, 2026.
The accurate prediction of aggregation attachment efficiency (α) is critical for suspended nanoparticle and microplastic fate in environmental systems, yet existing models struggle with nonlinear interactions and limited interpretability. This study evaluates two recently proposed hybrid ensemble machine learning frameworks, Improved Harris Hawks Optimized XGBoost (IHHO-XGBoost) and AdaBoost-ExtraTrees, for predicting α across mono- and binary-particle systems. Using a curated dataset spanning diverse particle types and environmental conditions, we demonstrate that IHHO-XGBoost outperforms six benchmark algorithms, achieving test R2 values of 0.865 (mono particle) and 0.797 (binary particle). SHAP analysis reveals distinct mechanistic drivers: salt concentration dominates mono particle aggregation, while zeta potential asymmetry controls binary systems. By adapting these advanced ensembles to colloidal stability prediction, this work provides a computational framework for improving the prediction of particle interactions in complex environmental matrices.
How to cite: Maalouf, M., AlMehairi, G., Omar, I. A., Tariq, M., Almaazmi, S., Katzourakis, V. E., and Chrysikopoulos, C. V.: Hybrid Ensemble Machine Learning Models with SHAP Explainability for Robust Prediction of Suspended Particle Attachment Efficiency in Complex Environmental Systems , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2706, https://doi.org/10.5194/egusphere-egu26-2706, 2026.
Groundwater contamination remains a significant environmental challenge, necessitating the development of advanced remediation strategies. One promising approach involves the injection of nanomaterials, such as nano-sized zero-valent iron (nZVI) or colloidal activated carbon, to degrade or immobilize contaminants in situ. The success of nanoremediation hinges on quantitative understanding of nanoparticle transport under geochemical conditions which may promote coagulation by accident or design. Within porous media, nanoparticles tend to undergo complex interactions, including coagulation after particle–particle collisions, leading to aggregation and deposition onto the solid–fluid interface. These interactions directly influence their mobility and retention, with potential implications for permeability alterations caused by pore clogging. A comprehensive understanding of these coupled mechanisms is essential for improving the design of injectable adsorptive or reactive contaminant barriers.
We develop here a pore network modeling (PNM) framework to simulate the transport and aggregation of unstable nanoparticles within a computer-generated porous medium. By incorporating the Smoluchowski coagulation model, the framework captures particle–particle interactions governing aggregation, while also considering particle–collector interactions that govern attachment and deposition on solid surfaces. The effects of ionic strength on both aggregation and deposition processes are explicitly examined. To capture the influence of aggregation on deposition, the collector contact efficiency is determined as a function of aggregate size and local pore-scale hydrodynamic conditions, using a neural-network model trained on pore-scale numerical simulations (Lin et al., 2022). Ionic strength regulates particle–particle collision efficiency, such that higher ionic strength enhances aggregation and promotes deposition. Furthermore, differences in the transport and retardation of dissolved salts and nanoparticles cause their concentration fronts to propagate at different velocities within the porous medium, leading to spatially heterogeneous aggregation and deposition zones. The insights gained from this research contribute to the advancement of pore-scale modeling techniques for nanoparticle transport and retention.
How to cite: Ioannidis, M., Mansourieh, A., and Gostick, J.: Transport of Unstable Nanoparticle Suspensions in Porous Media: Pore Network Model of Coagulation and Deposition, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4694, https://doi.org/10.5194/egusphere-egu26-4694, 2026.
The Krško aquifer in southeast Slovenia is a Quaternary intergranular system composed of highly permeable carbonate and silicate gravels. Due to its geological vulnerability and the surrounding land use that ranges from intensive agriculture to urban and industrial centres, the aquifer is susceptible to contamination. This study presents a comprehensive monitoring campaign initiated in September 2025 to capture seasonal variations in groundwater quality during the 2025-2026 winter recharge cycle. To characterize the chemical status of the aquifer, a multi-proxy analytical framework was implemented. The baseline characterization included a broad suite of physical and chemical parameters with major ions (e.g., NO3-, SO42-, Cl-, TOC, redox sensitive metals such as Fe and Mn, etc.). They were coupled with targeted quantitative grab sampling for a wide array of contaminants that include pesticides and metabolites, persistent organic contaminants such as Per- and Polyfluoroalkyl Substances (PFAS) and Volatile Halogenated Hydrocarbons (VHHs), pharmaceuticals and hormones. Parallel to grab sampling, Chemcatcher passive samplers were installed to provide time-weighted average concentrations of specific organic compounds. By comparing the validated quantitative laboratory results (LC-MS) with the results from the passive samplers, this research and integrated approach aim to refine groundwater vulnerability models and improve the reliability of chemical status assessments in porous alluvial systems.
How to cite: Perović, I. and Koroša, A.: Monitoring of emerging organic contaminants (EOCs) in Krško aquifer (Slovenia) by integrating passive and grab sampling, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16565, https://doi.org/10.5194/egusphere-egu26-16565, 2026.
Microplastics (MPs) are increasingly detected in wastewater treatment systems, where treatment plants act simultaneously as interception nodes and point sources via treated effluents and sludge management. This contribution synthesizes a PRISMA-guided critical review focused on Kazakhstan and Central Asia, benchmarking the region against a harmonized global dataset while explicitly interrogating how methodological choices drive inter-study variability.
A structured evidence map (2010–Sept 2025) was compiled and curated into a comparable database of 63 wastewater-treatment studies worldwide, yielding 402 matrix–stage observations across influent, effluent, and sludge streams. Observation-level descriptive statistics show that global raw influent concentrations cluster around 100 particles/L (median ≈65 particles/L), whereas final/tertiary effluents are typically 1 particles/L (median ≈2.2 particles/L). Overall MP removal increases from secondary treatment (median ≈85.5%) to tertiary/advanced trains (median ≈95.0%), while sludge acts as the dominant sink, retaining MP burdens on the order of 1000–100.000 particles/kg dry weight. Across matrices, fibers dominate the reported morphologies and polymer signatures are consistently led by PET/PES, PP, and PE, consistent with textile and packaging sources.
Central Asian plant-level evidence remains extremely limited (two eligible wastewater treatment plants case studies, both in Kazakhstan), but when comparisons are restricted to like-for-like analytical windows, influent levels align with the global interquartile range. In contrast, secondary-only configurations tend to place effluent concentrations in the upper half of the global envelope, supporting the inference that the presence/absence of post-secondary barriers (filtration, DAF/BAF, membranes/MBR) is the primary determinant of regional performance relative to international benchmarks. The review identifies three dominant uncertainty drivers—sampling representativeness (grab vs. composite), minimum size cut-offs (especially <100 µm), and incomplete quality assurance and quality control (QA/QC) reporting—and proposes an actionable 2025–2030 agenda: ISO-aligned protocol harmonization with explicit QA/QC, expansion of monitoring to tertiary/advanced trains, coordinated interlaboratory ring trials and reference-library development, and integration of monitoring with hydrodynamic/fate models to translate plant upgrades into reach-scale benefits in arid, episodic-flow receiving waters.
How to cite: Rodrigo-Clavero, M.-E., Rodrigo-Ilarri, J., Alimova, K. K., Salikova, N. S., Makeyeva, L. A., Berdali, M., and Kyzylbayev, N.: Microplastics in Central Asian Wastewater Systems: Analytical Workflows, Quality Assurance, Quality Control, Uncertainties, and Research Priorities, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10646, https://doi.org/10.5194/egusphere-egu26-10646, 2026.
In recent years, microplastics have become a pollutant of global concern: they have been identified in virtually every environment, including the hydrosphere, atmosphere and pedosphere. A growing amount of research now focuses on their impact on these environments. In this context, however, rocks have largely been overlooked.
In particular, sedimentary rocks constitute the majority of Earth’s exposed surface and are widely used as building materials, notably in cultural heritage. Serving as an important interface between the atmosphere, the terrestrial environment and human influences, they are likely susceptible to microplastic pollution and could potentially act as (temporary) storage media for microplastics. This could have implications for the long-term durability and weathering behaviour of the rocks.
The goal of this research, funded by the Research Foundation - Flanders (FWO), is therefore to gain more insight into the interaction between sedimentary rocks and microplastics. Specifically, we aim to investigate the factors that control microplastic adhesion to rock surfaces and examine how these pollutants might modify the physical and water transport properties of the rock. Given the inherent heterogeneity of sedimentary rocks and the many anticipated factors involved in this interaction (e.g. rock specific properties, microplastic specific properties, environmental conditions), this is a challenging task that requires a systematic approach.
Our experimental setup involves four types of sedimentary rock with variable physical properties that commonly occur in Belgium: Lede sandy limestone, Bentheimer sandstone, Maastricht limestone and Belgian Blue limestone. The rocks were treated with a selection of the most prevalent microplastic types (polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), and polyethylene terephthalate (PET)) and studied using advanced visualization and characterization methods, including light microscopy, micro-computed tomography and 3D profilometry. Contact angle measurements were also performed to evaluate changes in rock-water interaction after microplastic exposure.
The preliminary findings of this study indicate that microplastics can alter the roughness of the rock surface, though this effect depends on the type of rock. We also observed that microplastics tend to reduce the wettability of rock surfaces. This effect is most likely due to the hydrophobic nature of the microplastics.
Furthermore, the preliminary findings suggest that rock surface roughness and (surface) porosity can facilitate microplastic adherence to the rock surface. Moreover, certain microplastic types seem to have a greater affinity to attach to rocks than others. We anticipate that additional factors, such as environmental conditions, microplastic characteristics and rock characteristics, play a role in this interaction as well. Further study is required to determine the extent of their influence.
How to cite: De Lathauwer, H., Cnudde, V., Schröer, L., and De Viaene, T.: Tiny plastics, big impact? Towards an improved understanding of the interaction between microplastics and sedimentary rocks., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17092, https://doi.org/10.5194/egusphere-egu26-17092, 2026.
Plastics exposed to environmental conditions can develop eco-coronas. Here, we investigated how the eco-corona impacts the surface properties and transport of nanoplastics in unsaturated sand. Four different plastics, polyethylene (PE), polypropylene (PP), polystyrene (PS), and poly(butylene adipate terephthalate)-based (PBAT) were used in pristine and UV-weathered forms. The nanoplastics were exposed to a water-extractable soil solution to form an eco-corona. Transport of nanoplastics was studied under unsaturated flow condition at 40\% water saturation. Weathering and eco-corona had no obvious effect on the transport of nanoplastics under low ionic strength conditions. For most UV-weathered nanoplastics the zeta potentials became less negative after UV-weathering, indicating decreased surface charge, except for PBAT, whose zeta potentials became considerably more negative after weathering. The eco-corona caused the zeta potentials of the different nanoplastics to become more similar, except for pristine PBAT, which had a considerably less negative zeta potential than the other plastics. The eco-corona decreased contact angles in some cases (PP and PS) but increased the contact angle in others (PE and PBAT). This study demonstrates that both UV-weathering and eco-corona formation modify the physicochemical properties of nanoplastics, such as surface charge and hydrophobicity, with a tendency to make different plastics more similar.
How to cite: Flury, M., Zhou, X., and Yu, Y.: Impacts of Eco-Corona on Surface Properties of Nanoplastics, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6039, https://doi.org/10.5194/egusphere-egu26-6039, 2026.
Nanoplastics in soil are exposed to soil solution, which is a mixture of microbial metabolites, dissolved organic matter, mineral and organic colloids, as well as inorganic ions. These components can interact with nanoplastics, thereby altering their surface properties and environmental behavior. Here, we examined how soil solution affects the aggregation kinetics and colloidal stability of nanoplastics made from a soil-biodegradable plastic (poly(butylene adipate-co-terephthalate), PBAT) and a conventional plastic (polyethylene). We found that both PBAT and polyethylene nanoplastics formed bigger aggregates in the presence of a soil solution extracted from a sandy loam soil, suggesting that the soil solution promoted the aggregation of both nanoplastics, thereby reducing their colloidal stability. Fluorescent excitation–emission spectroscopy revealed that microbial biomass in the soil solution dominantly adsorbed onto nanoplastics, followed by humic acid, forming an eco-corona that induced polymer bridging and attractive patch-charge interactions. Despite the observed bigger aggregates, the critical coagulation concentrations did not decrease correspondingly for either PBAT or polyethylene nanoplastics, which is likely due to the uncertainties of the critical coagulation concentrations as well as the hetero-aggregation between nanoplastics and colloids present in the soil solution. These results indicate that interactions with soil solution can decrease the colloidal stability of nanoplastics via eco-corona formation and hetero-aggregation, underlining the role of the complex interactions between nanoplastics and their surrounding matrices on the environmental behavior of nanoplastics.
How to cite: Yu, Y. and Flury, M.: Soil Solution Promotes Nanoplastic Aggregation via Eco-corona Formation and Hetero-aggregation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6135, https://doi.org/10.5194/egusphere-egu26-6135, 2026.
