23–28 August 2026 OREA Congress Hotel Brno 23RD MEETING OF THE IHSS 9TH IWA SPECIALIST CONFERENCE ON NOM www.ihss-iwa2026.com Book of Abstracts
Please note: The abstracts included in this Book of Abstracts have not undergone language editing or proofreading. They are published as submitted by the authors, who bear full responsibility for their language and content.
BOOK OF ABSTRACTS 3 IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 Content Plenary Lecture ������������������������������������������������������������������������������������������������������������������������������4–6 Keynote Lecture ��������������������������������������������������������������������������������������������������������������������������� 7–14 Monday, 24 August 2026 Analysis and Characterization ��������������������������������������������������������������������������������� 15–47 Tuesday, 25 August 2026 Analysis and Characterization ���������������������������������������������������������������������������������48–58 Technologies and Applications ������������������������������������������������������������������������������59–66 Research Frontiers ������������������������������������������������������������������������������������������������������ 67–81 Environment, Agriculture, and Forestry ������������������������������������������������������������ 82–93 Thursday, 27 August 2026 NOM and Aquatic Systems ������������������������������������������������������������������������������������ 94–130 Soil Organic Matter, Caustobiolites, and Biochar ������������������������������������� 131–153 Friday, 28 August 2026 Environment, Agriculture, and Forestry ������������������������������������������������������� 154–156 NOM and Aquatic Systems ���������������������������������������������������������������������������������� 157–160 Travel Awardee Presentations ���������������������������������������������������������������������������161–177 Poster Session Analysis and Characterization ���������������������������������������������������������������������������� 178–188 Soil Organic Matter, Caustobiolites, and Biochar �������������������������������������189–208 NOM and Aquatic Systems ���������������������������������������������������������������������������������� 209–214 Environment, Agriculture, and Forestry ������������������������������������������������������� 215–256 Technologies and Applications ������������������������������������������������������������������������� 257–279 Research Frontiers ���������������������������������������������������������������������������������������������������������� 280 Name index ���������������������������������������������������������������������������������������������������������������������������� 281–283
IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 4 PL Supramolecular Structure of NOM and EfOM: Analytical Evidence Martha J. M. Wells1 1 EnviroChem Services, 2613 Cherington Drive, Auburn, Alabama, USA 36832 info@envirochemservices.net or mjmwells@tntech.edu During the past quarter century, conceptualization of the supramolecular structure of fulvic and humic acids in soil science has developed, championed by the pioneering and ongoing research of Piccolo [1–3]. Advances in analytical instrumentation and techniques have likewise driven the quest for better understanding of the architecture of aquatic natural organic matter (NOM) and not-so-natural effluent organic matter (EfOM). The supramolecular view of aquatic OM aggregates was expanded to a conceptual model [4–5] of a dual metachemical—physical hydrogel structure arranged in a hierarchical “supramolecular within supramolecular” self-assembling architecture in which metachemical hydrogels (≤1 μm diameter) are corralled within a dispersible physical hydrogel scaffold (>1 μm diameter). Moderate and strong H-bonding in addition to weak H-bonds, van der Waals forces, entanglement, and metal bridging are proposed to participate in supramolecular, self-assembled aggregation. The dispersible physical hydrogel scaffold was observed to form, dissipate, and spontaneously reform over turbulent/ quiescent cycles (shearing) indicating reversible and reproducible abiotic self-assembly. Beyond the existence of the supramolecular character of humic substances, interest in understanding its significance and the purpose for which OM evolved in nature to provide essential functions in soil and water environments, is growing. In EfOM, “nonliving” organic carbon, comprised of plant and animal detritus, waste materials, and pollutants, exists in a myriad of forms—diagenetic (“long dead” degraded and rearranged fulvic and humic acids), biogenic (“recently dead or excreted” extracellular hydrophilic acids, amino acids, proteins, sugars, polysaccharides, carbohydrates, lipids, and nucleic acids), and anthropogenic (“synthetic” pesticides, pharmaceuticals and personal care products (PPCPs), macro-, micro- and nanoplastics, per- and polyfluoroalkyl substances (PFAS), etc.). Diagenetic, biogenic, and anthropogenic compounds commingle as supramolecular, macromolecular, and molecular forms, thereby affecting removal by water treatment processes [6, 7]. Empirical data from studies using flow field-flow fractionation (flFFF) [8],
BOOK OF ABSTRACTS 5 IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 dynamic light scattering (DLS) [9, 10], nanoparticle tracking analysis (NTA) [11], and excitation-emission matrix fluorescence spectroscopy with parallel factor analysis (EEM-PARAFAC) [12] will be presented to support this discussion. Applications including NOM/EfOM in aquatic ecosystems [13], removal via water reuse processes [14], and prediction of disinfection byproducts will illustrate the impacts of aquatic organic supramolecular structures. References 1. A. Piccolo, Soil Science 166(11) (2001) 810. 2. A. Piccolo, Advances in Agronomy 75 (2002) 57. 3. A. Piccolo, M. Drosos, Advances in Agronomy 188 (2024) 405. 4. M.J.M. Wells, H.A. Stretz, Science of the Total Environment 671 (2019) 1125. 5. M.J.M. Wells, Journal of Environmental Quality 48 (2019) 1644. 6. J.M. Sanez, K.Y. Bell, M.J.M. Wells, Science of the Total Environment 896 (2023) 165149. 7. K.N. Mealio, M.J.M. Wells, K.Y. Bell, D. Wolgemuth, H.A. Stretz, Journal of Environmental Chemical Engineering 12 (2024) 113864. 8. M.J.M. Wells, Chromatography 2 (2015) 580. 9. M.R. Esfahani, H.A. Stretz, M.J.M. Wells, Science of the Total Environment (2015) 537 81. 10. K.N. Mealio, K.E. Slamen, M.J.M. Wells, H.A. Stretz, Science of the Total Environment 963 (2025) 178463. 11. M.J.M. Wells, J.Y. Chen, J. Bodycomb, D. Wolgemuth, H.A. Stretz, G.A. Zacheis, M. Bautista, K.Y. Bell, Science of The Total Environment 949 (2024) 174985. 12. M.J.M. Wells, J. Hooper, G.A. Mullins, K.Y. Bell, Science of the Total Environment 820 (2022) 153070. 13. M.J.M. Wells, G.A. Mullins, K.Y. Bell, A.K. Da Silva, E.M. Navarette, Environmental Science & Technology 51 (2017) 13592. 14. M.J.M. Wells, D. Funk, G.A. Mullins, K.Y. Bell, Science of the Total Environment 886 (2023) 163937. Acknowledgement The encouragement of Drs. K.Y. Bell, H.A. Stretz, A. Piccolo, and M.H.B. Hayes was vital to this research. PL Plenary Lecture KL Keynote Lecture SL Standard Lecture TA Travel Awardee P Poster
IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 6 PL Organic Matter Photochemistry and the Sulfur Cycle Kristopher McNeill1 1 ETH Zurich, Institute of Biogeochemistry and Pollutant Dynamics, Universitätstrasse 16, 8092 Zürich, Switzerland Photochemical reactions are becoming more recognized for their role in the fate of dissolved organic sulfur (DOS) in natural waters, yet many questions remain. Recent work shows that sunlight converts a wide range of DOS compounds to sulfate and lowmolecular-weight S products, and that triplet-sensitized one-electron oxidation followed by SO2/S(IV)/SO4²– conversion may represent a general mechanism [1,2]. Building on these findings, we have begun to investigate how photochemistry shapes DOS cycling in the surface ocean and inland lakes. We combine field measurements, controlled irradiation experiments, and mechanistic studies to (i) assess whether photomineralization contributes to the “missing sink” of oceanic DOS, (ii) quantify DOS photooxidation across lakes with diverse sulfur geochemistry, and (iii) resolve oxidation pathways for representative biosynthetic, sulfurized, and petroleum-derived organosulfur compounds. This work will seek to clarify the magnitude and mechanisms of DOS photooxidation, improve predictions of organosulfur fate, and strengthen links between aquatic photochemistry, biogeochemical sulfur cycling, and climate-relevant sulfur fluxes. The results will be relevant to environmental chemistry, biogeochemistry, atmospheric chemistry, water treatment, and geoscience. References 1. R. Ossola, J. Tolu, B. Clerc, P. R. Erickson, L. H. E. Winkel, K. McNeill, Environ Sci Technol 53 (2019), 13191-13200. 2. R. Ossola, B. Clerc, K. McNeill, Environ Sci Technol 54 (2020), 13066-13076. Acknowledgement We gratefully acknowledge that funding for this work comes from the Swiss National Science Foundation, grant numbers 200020_188565 and 200021228211.
BOOK OF ABSTRACTS 7 IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 KL Organic Chemical Diversity Beyond Earth: C-, N-, S- and P-cycling from Earth to other parent bodies Philippe Schmitt-Kopplin1, 2, 3 1 Technical University Munich TUM, analytical Food Chemistry, Weihenstephan, Freising, Germany 2 Helmholtz Munich, analytical BioGeoChemistry, Oberschleißheim, Germany 3 Max Plank Institute for Extraterrestrial Physics, Center for Astrochemical Studies, Garching, Germany schmitt-kopplin@tum.de Understanding complex organic mixtures in bio- and geosystems at the molecular level remains a major challenge in modern science. From an analytical chemistry perspective, this endeavor demands the continuous development of high-resolution analytical technologies and innovative approaches for advanced data interpretation. Our goal is to reveal the chemical diversity and complexity of organic natural mixtures shaped by both biotic and abiotic processes. We present conceptual frameworks and experimental results that illustrate the breadth of chemical complexity across diverse systems—from life (Metabolomics), to post-life (Organic Geochemistry in water systems), towards pre-life stages (Astrochemistry). These interconnected domains highlight the analytical challenges in characterizing dynamic molecular systems. Examples and applications are drawn from ongoing projects, including studies profiling the chemistry within the terrestrial biogeochemical continuum in water systems and investigations of extraterrestrial environments. We emphasize the role of non-enzymatic processes in linking and regulating chemistry across these supersystems. Particular attention is given to the carbon, sulfur, nitrogen and phosphorous chemistry in meteorites, providing insights into abiotic parentbody processes. These concepts and findings are essentials to interpret data from sample-return missions such as HAYABUSA2 and OSIRIS-REx, which delivered CHNOPS material from the asteroids Ryugu and Bennu in collaboration with JAXA and NASA.
IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 8 KL Thermodynamic and Calorimetric Quantification of Soil Organic Matter Turnover Thomas Maskow1, Du Yuan1, Shiyue Yang1, Christian Fricke2,3, Marcel Lorenz4,5, Eliana di Lodovico1,2, Anja Miltner5, Mathias Kästner5 1 Helmholz Centre for Environmental Research-UFZ, Department Microbial Biotechnology, Permoserstr. 15, 04318 Leipzig, Germany, e-mail: thomas.maskow@ufz.de 2 RPTU Kaiserslautern-Landau, iES Landau, Institute for Environmental Sciences, Group of Environmental and Soil Chemistry, R, Fortstraße 7, 76829 Landau, Germany 3 Duale Hochschule Sachsen - Staatliche Studienakademie Riesa, University of Cooperative Education, Rittergutstraße 6, 01591, Riesa, Germany 4 Trier University, Soil Science, FB VI, Behringstraße 21, 54296 Trier, Germany 5 Helmholz Centre for Environmental Research-UFZ, Department Molecular Environmental Biotechnology, Permoserstr. 15, 04318 Leipzig, Germany Soil organic matter (SOM) turnover is commonly described in terms of carbon pools, microbial activity, and mass balances. However, organic matter entering soil is not only a source of carbon and nutrients, but also a carrier of chemical energy. During microbial decomposition, this energy is partially lost trough respiratory processes and dissipation as heat, while the remaining fraction is conserved in microbial biomass, necromass, and ultimately stabilized SOM. Quantifying these energy transformations may therefore provide an additional perspective on soil carbon cycling and on the mechanisms controlling SOM persistence [1]. In this contribution, I will present how calorimetric and thermodynamic approaches can be used to complement classical carbon-based descriptions of SOM turnover. Isothermal calorimetry and calorespirometry allow microbial heat production to be linked with CO2 or O2 fluxes, thereby coupling stoichiometric balances with enthalpy balances and providing access to reaction enthalpies, and energy dissipation during microbial turnover in combination with thermodynamc modelling. These measurements can be further used to estimate thermodynamic state functions such as Gibbs energies and entropies, and use efficiencies of carbon (CUE) and energy (EUE). By combining carbon and energy balances, these approaches make it possible to distinguish whether SOM turnover primarily results in respiratory losses, heat dissipation, or the formation of microbial biomass and necromass. In addition, combustion calorimetry and thermal analysis provide information on the chemical energy stored in SOM itself, which is required to close energy balances and to develop thermodynamically consistent models of soil carbon turnover.
BOOK OF ABSTRACTS 9 IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 Using examples from recent experimental work, I will show how heat production rates, respiratory fluxes, isotope-labelled substrates, and energycontent measurements can be combined to quantify microbial turnover processes in soil systems. Particular emphasis will be placed on the methodological challenges of applying calorimetric and thermal analytical techniques to heterogeneous, low-carbon soil samples and on the opportunities arising from linking energetics with stoichiometric and thermodynamic modelling. Overall, the presentation proposes that energy should be treated as an explicit state and balance variable in soil biogeochemistry. Such a thermodynamic perspective does not replace carbon-based approaches, but can reveal constraints, efficiencies, and transformation pathways that remain hidden when soil organic matter turnover is considered only as a redistribution of carbon. References 1. M. Kästner, T. Maskow, A. Miltner, M. Lorenz, S. Thiele-Bruhn, Soil Biology and Biochemistry (2024) 109403. Acknowledgement We acknowledge financial support from the Helmholtz Centre for Environmental Research – UFZ and from the German Research Foundation (DFG) through projects TH 678/25-1, MA 3746/8-1, MA 3746/8-2, MA 3746/9-1, and MA 3746/9-2.
IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 10 KL Deciphering the Molecular Composition of Biological NOM and Its Transformation During Disinfection Using a Novel MS-Based Approach Pei Guo, Yufei Chen, Rong Liu, Guangrong Sun, Wei Wang1 1 College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China The extensive utilization of a variety of impaired water supplies in recent years has substantially increased the proportion of biological NOM in source water, which include biomolecules originating from cells, tissues, excreta, and detritus from microbes, plants, and animals at relatively early stages of decomposition. Among them, nucleic acids, which serve as essential, ubiquitous genetic substances across almost all living organisms, enter source waters through natural cell lysis as well as external inputs from agricultural runoff, discharge from livestock husbandry, industrial wastewater, and urban sewage. However, the molecular composition, structural diversity, and transformation pathways of nucleic acids remain poorly understood due to its extreme complexity and the limitations of conventional analytical approaches. In this study, we developed a novel mass spectrometry (MS)-based approach integrating advanced molecular characterization and computational analysis to decipher the molecular composition of biological NOM and track its transformation during disinfection.
BOOK OF ABSTRACTS 11 IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 KL Humic Substances as Drivers of Carbon Footprint Reduction: Linking Environmental Remediation, Soil Health and Sustainable Agriculture Adele M. Muscolo Department of AGRARIA, Mediterranea University of Reggio Calabria, Italy The increasing environmental pressures associated with intensive agricultural systems, including greenhouse gas emissions, soil degradation, biodiversity loss, water contamination, and depletion of soil organic carbon (SOC), are accelerating the need for sustainable and regenerative agricultural strategies. Conventional input-intensive farming models, strongly dependent on synthetic fertilizers and linear resource consumption, have contributed significantly to climate alteration and ecosystem instability, particularly in fragile Mediterranean agroecosystems characterized by low organic matter content and high vulnerability to desertification processes. Within this framework, European policy frameworks such as the European Green Deal, the Farm to Fork Strategy, the EU Soil Strategy for 2030, and emerging carbon farming initiatives are increasingly promoting the transition toward climate-smart and resource-efficient agricultural systems capable of combining productivity with environmental sustainability. In this context, humic substances (HS) are emerging as multifunctional ecological regulators capable of simultaneously improving soil functionality, enhancing carbon sequestration, reducing environmental pollution, and supporting sustainable agricultural productivity. Beyond their traditional role as stable fractions of soil organic matter, HS are increasingly recognized as dynamic bioactive compounds involved in nutrient cycling, microbial stimulation, pollutant immobilization, water retention, and modulation of soil biochemical processes. Their ability to influence the soil–plant–microbiome nexus places them at the center of new strategies aimed at restoring ecosystem resilience and reducing the environmental footprint of agricultural production systems. Particular attention is currently being devoted to the valorisation of agroindustrial residues and organic wastes as renewable sources for the generation of HS-rich amendments within circular bioeconomy frameworks. Composts, vermicomposts, digestates, and innovative sulfur–bentonite formulations enriched with agro-food by-products represent promising examples of engineered organic matrices capable of transforming waste into functional carbon resources. These materials not
IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 12 only recycle nutrients and reduce waste disposal burdens but also contribute to long-term soil carbon stabilization and improved ecosystem services. Recent experimental evidence demonstrates that HS-based amendments can significantly enhance soil biochemical and microbiological functionality through the stimulation of enzymatic activities such as dehydrogenase, fluorescein diacetate hydrolysis, urease, and catalase, while simultaneously promoting microbial biomass development and increasing soil biodiversity. Improvements in soil structure, cation exchange capacity, nutrient buffering, and waterholding capacity further contribute to increased resilience against drought and environmental stress conditions. Furthermore, the integration of multiindicator approaches combining chemical, microbiological, biochemical, and faunal parameters has proven effective in detecting early changes in soil quality and ecosystem functionality following HS application. From a climate mitigation perspective, HS-based amendments represent promising low-impact solutions capable of simultaneously enhancing soil carbon stabilization and reducing the environmental burden of agricultural production. Life Cycle Assessment (LCA) approaches increasingly confirm the sustainable advantages of HSderived products obtained from agroindustrial residues over conventional fertilization systems, highlighting reductions in greenhouse gas emissions, eutrophication potential, and fossil resource consumption and increment in circular resource efficiency. Moreover, the ability of HS to promote long-term soil organic carbon sequestration highlights their potential relevance within emerging carbon credit and carbon farming frameworks, where regenerative soil management practices may contribute to measurable climate mitigation outcomes and the generation of ecosystem service value. These findings reinforce the strategic role of HS within regenerative and climate-smart agricultural systems aimed at supporting ecosystem restoration, sustainable food production, and the transition toward low-carbon circular bioeconomies, consistently with the targets established by the European Green Deal and related EU sustainability strategies. We will explore the emerging role of humic substances as strategic tools for connecting environmental remediation, soil restoration, climate mitigation, and sustainable food production. Particular attention will be devoted to innovative circular approaches based on the valorisation of agro-industrial residues, the application of integrated biological and biochemical soil quality indicators, and the development of naturebased solutions aimed at restoring soil functionality while maintaining productive and economically viable agricultural systems. Finally, future perspectives on the application of HS in regenerative agriculture, microbiome engineering, carbon farming, and climate-resilient
BOOK OF ABSTRACTS 13 IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 agroecosystems will be discussed, highlighting the transition from conventional input-based agriculture toward ecological models centered on functional carbon management and ecosystem restoration.
IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 14 KL Molecular Modeling and Simulation of Soil Components Chris Oostenbrink BOKU University, Department of Natural Sciences and Sustainable Resources, Institute for Molecular Modeling and Simulation, Muthgasse 18, 1190 Vienna, Austria Molecular dynamics simulations give insight into molecular processes at a resolution that is often inaccessible by experiments. The structure and (thermo)dynamics of small molecules interacting with various media are commonly studied by computer simulations in material sciences and biomolecular sciences. However, extensive molecular simulations of soil constituents are hampered by ill-defined molecular systems and restrictions in the description of the relevant interactions. The Vienna Soil-Organic-Matter Modeler opened a way to create realistic models of such systems, allowing to link macroscopic properties to molecular interactions and processes. In particular the interactions with small organic molecules and with mineral surfaces are of high relevance. I will highlight some of our recent developments to advance the field of molecular simulations on soil components.
BOOK OF ABSTRACTS 15 IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 Monday, 24 August 2026 / Hall B+C Analysis and Characterization SL1 Unfolding the Conformational Structure of Supramolecular Humeomes in 8 M Urea Alessandro Piccolo1, Marios Drosos2, Giovanni Vinci3 1 Alessandro Piccolo, Dipartimento di Agraria, Università di Napoli Federico II, Piazza Carlo di Borbone 1, Portici, 80055, Italy, alessandro.piccolo@unina.it. 2 Marios Drosos, Dipartimento di Scienze Agrarie, Forestali, Alimentari e Ambientali (DAFE), Università della Basilicata, Viale Dell’Ateneo Lucano 10, Potenza, 85100, Italy. 3 Giovanni Vinci, Dipartimento di Agraria, Università di Napoli Federico II, Piazza Carlo di Borbone 1, Portici, 80055, Italy. We dissolved in 8 M urea solution molecularly characterized humeomes [1] isolated from either soils or geochemical sources to follow their conformational behavior when eluted in a high-performance size-exclusion chromatography (HPSEC) system and detected by both UV and Refractive Index (RI) detectors. The UV-detected chromatographic profile showed only an intense absorbance at the column void volume, where the RI detector instead revealed just a small peak. Concomitantly, the large humeomes mass was RI-detected as a large absorption uniquely at the column total volume. This peculiar behavior was explained with the highly structured urea-water network exerting a strong hydrophobic effect [2, 3] that forced the apolar humic molecules into apparently large clusters eluting at the void volume of the HPSEC column, while polar and medium polar components were separated from each other by the strong hydrogen bonding capacity of the urea solution and diffused through the column micropores up to the total volume. The intensity difference between UV and RI detections indicates that the UV-detected hydrophobic assemblies contained only few aromatic groups, but their enforced proximity favored mutual charge-transfer interactions, thus providing a hyperchromic effect [4, 5] with absorbances larger than the sum of single aromatic chromophores. Three different soils incubated for one year with maize residues provided HPSEC profiles which suggested altered humic composition. Changes in aromatic groups, as revealed by 13C-NMR spectra, affected the intensity of UV-detected peaks of hydrophobic clusters, while different amounts of polar and medium-polar molecules determined the humeomes conformational rigidity, varying the RI signals at the column total volume. Our results indicated that a concentrated urea solution was capable to unfold the weakly-bound humic associations and efficiently
IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 16 Analysis and Characterization Monday, 24 August 2026 / Hall B+C separating components of different chemical affinity, thereby confirming the supramolecular structure of humeomes, and representing a useful technique to simplify their heterogeneity, facilitate their molecular characterization, and understand their role in the agroecosystem. References 1. A. Piccolo, M. Drosos, Advances in Agronomy 188 (2024) 405. 2. C. Tanford, The Hydrophobic Effect: Formation of Micelles and Biological Membranes, Krieger, Malabar, FL., 1991. 3. J.N. Israelachvili, Intermolecular and Surface Forces. Elsevier, Academic Press, London, UK, 1994, p. 282. 4. C. Ma, K. Ye, S. Yu, et al., Dyes Pigments 74 (2007) 141. 5. T. Zhang, X.Y. Lou, X. Li, et al., Advanced Materials 35 (2023) 2210551.
BOOK OF ABSTRACTS 17 IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 Monday, 24 August 2026 / Hall B+C Analysis and Characterization SL2 Visualizing Organic Matter Quality Differences with Ultra-High-Resolution Mass Spectrometry Peter Herzsprung1, Wolf von Tümpling2, Norbert Kamjunke2, Oliver Lechtenfeld3 1 UFZ – Helmholtz Centre for Environmental Research, Dep. Lake Research, Brückstraße 3a, Magdeburg 39114, Germany, peter.herzsprung@ufz.de 2 UFZ – Helmholtz Centre for Environ. Research, Dep. River Ecology, Brückstraße 3a, Magdeburg 39114, Germany 3 UFZ – Helmholtz Centre for Environ. Research, Dep. Environ. Anal. Chem., Permoserstr. 15, Leipzig-04318, Germany The composition of natural organic matter (NOM) remains a conundrum. The highest resolution for elemental compositions of NOM can be achieved by Fourier- transform ion cyclotron resonance mass spectroscopy (FTICR-MS). This tool generates elemental compositions (i.e., molecular formulas, MFs) of thousands of NOM components which can be extracted from aqueous samples (e.g., via solid phase extraction, SPE) and which are ionizable (e.g. via negative mode electrospray ionization). NOM is not an inert mixture of compounds and its composition may be altered by photochemical or microbial reactions, adsorptive fractionation, or mixing of different water sources. In order to comprehend such NOM quality changes, specific data evaluation methods are required. The simplest approach to compare NOM quality between two samples is the presence of components in one sample and the absence in the other sample and display in van Krevelen diagrams (H/C versus O/C) or other descriptor combinations like H/C versus mass [1,2,3]. If several samples have to be compared, this approach is limited because of increasing possibilities of unique and partially shared MF with increasing number of samples [2]. Such partially shared MF often show low abundance (small peak magnitudes near the S/N threshold) [3]. A second, more sophisticated approach is the direct comparison of normalized peak magnitudes formula by formula and sample by sample for the shared formulas (i.e., present in all samples which are compared). A statistically robust method is the peak magnitude ranking and the calculation of inter sample ranking. The visualization of inter sample ranks can be easily realized in van Krevelen diagrams as well [2,3]. In this way, the abundance trends of biogeochemically similar groups of molecules (having similar molecular descriptors and reactivity) can be followed. KEY-components represent MF with the biggest impact on DOM quality difference [4] and can be performed by plotting of normalized peak magnitudes
IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 18 Analysis and Characterization Monday, 24 August 2026 / Hall B+C (direct infusion FTICR-MS [4]) or raw peak magnitudes (UHPLC-FTICR-MS [5]) versus time or space (e.g. lake depth). Depth profiles, for example in reservoirs or sediment pore-waters [4] or reaction time courses - for example photochemical transformations [4,5] – can be obtained for single MF. The KEY-components can be obtained by calculation of maximum relative abundance differences [4,5]. Overall, the presented approaches support a better understanding of NOM processing. Potential adsorption / desorption could be understood in sediment pore waters of an acidic mining lake [2]. The transformation of riverine NOM from terrestrial source to sea could be followed [6]. Highly reactive components could be identified by combining a photo degradation experiment with drinking water reservoir depth and seasonal dependent monitoring [4]. Photo degraded components, photo products, resistant components and intermediate products could be identified [5] after irradiation of an effluent organic matter sample and waste water treatment. References 1. Tang, G. et al., Environ. Pollut. 306 (2022) 119416. 2. Herzsprung et al., Org. Geochem. 108 (2017) 51. 3. Herzsprung et al., Environ. Sci. Technol. 46 (2012) 5511. 4. Herzsprung et al., Water Res. 232 (2023) 119672. 5. Herzsprung et al., Environ. Sci. Technol. 59 (2025) 13787. 6. Kamjunke et al., Water Res. 288 (2026) 124613. Acknowledgement The funding source identification and acknowledgement may be placed here.
BOOK OF ABSTRACTS 19 IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 Monday, 24 August 2026 / Hall B+C Analysis and Characterization SL3 From Dilution Simulations to 13C NMRDerived Endmembers – and Beyond: Insights into Humic Substances Mikhail Borisover1, Edgar Galicia-Andrés2,3, Marcos Lado4, Drazen Petrov2, Chris Oostenbrink2 1 Volcani Institute, Agricultural Research Organization, Institute of Soil, Water and Environmental Sciences, 68 HaMakabim Str. POB 15159 Rishon LeZion, 7505101, Israel, vwmichel@volcani.agri.gov.il 2 Institute of Molecular Modeling and Simulation, University of Natural Resources and Life Sciences (BOKU), Muthgasse, 18, 1190, Vienna, Austria 3 Institute of Soil Research, University of Natural Resources and Life Sciences (BOKU), Gregor-Mendel-Strasse 33, 1180, Vienna, Austria 4 Interdisciplinary Center for Chemistry and Biology (CICA), Faculty of Sciences, University of A Coruña, As Carballeiras, s/n, Campus Elviña, 15071 A Coruña, Spain Molecular modeling offers a way to probe the conformational and aggregation-related organization of humic substances (HS), enabling controlled “virtual experiments” that complement laboratory observations. One test to examine the molecular organization of HS is to explore the response of HS systems to dilution, a process directly linked to aggregate stability in aqueous environments. In this work, molecular dynamics simulations based on models generated with the Vienna Soil Organic Matter Modeller were used to examine the stability and evolution of Leonardite humic acid aggregates across a broad range of water contents, spanning conditions from water-rich HS phases to dilute HS solutions, by varying molecular sizes, ionization states, and counter-ion types (Na⁺, Ca²⁺) [1]. The simulations tracked the gradual decomposition of HS aggregates upon dilution, quantified through changes in intermolecular contacts, hydrogen bonding, cluster size distributions, and interaction energies. The results suggest that dilution induces a stepwise disaggregation process lacking a cooperative character, in which large assemblies progressively dissociate, highlighting the sensitivity of HS organization to the ionic environment. These findings provide a mechanistic framework for interpreting experimental observations of HS size distributions and dialysis behavior. These simulations also raise a fundamental question: what structural entities should be used as molecular inputs in such models? Earlier observations proposed that multiple HS can be represented as a mixture of a very limited number of independent components [2]. To address this on a quantitative basis and obtain uniquely
IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 20 Analysis and Characterization Monday, 24 August 2026 / Hall B+C identified endmembers, we examined whether bulk compositional data could reveal recurring “endmember” motifs suitable for guiding molecular model representations. Using an HS dataset of the International Humic Substances Society, single- and multiblock nonnegative multivariate curve resolution-alternating least squares (MCR-ALS) decompositions were performed to integrate ¹³C NMR spectra with elemental composition and acidic functional group contents data [3]. Multiblock MCR-ALS analysis constrains the compositional space, contributing to the identification of unique, chemically meaningful components. Across diverse samples, two chemically distinct and nearly unique components representing an aromatic-rich and an aliphatic-rich motif, similarly hydrophilic in terms of contents of carboxylic and phenolic groups, consistently emerged, together explaining ~97–98% of the total variance while exhibiting minimal residual rotational ambiguity and pointing to the unique character of decomposition. Taken together, these results suggest a pathway in which data-driven compositional analysis informs molecular simulations. The MCRderived compositional endmembers offer chemically grounded ensemble descriptors that can serve as inputs for constructing more realistic molecular models. Bridging these approaches, we suggest a strategy in which experimentally derived endmembers guide the generation and testing of HS structures in silico, potentially improving the interpretability and predictive power of molecular modeling of HS and natural organic matter, in particular, helping to identify extreme behaviors within the compositional space defined by the data. Incorporating additional constraints into molecular models, such as the contents of carboxylic and phenolic groups or specific elemental ratios, may enable the development of even more realistic representations of the molecular HS ensembles. References 1. M. Borisover, D. Petrov, C. Oostenbrink, E. Galicia-Andrés, Colloids and Surfaces A: Physicochemical and Engineering Aspects 704 (2025) 135507. 2. A.C. García, T.A., van Tol de Castro, L.A. Santos, O.C.H. Tavares, R.N. Castro, R.L.L. Berbara, J.M. García-Mina, Journal of Environmental Quality 48 (2019) 1622. 3. M. Borisover, M. Lado, Minerals 16 (2026) 228.
BOOK OF ABSTRACTS 21 IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 Monday, 24 August 2026 / Hall B+C Analysis and Characterization SL4 Humins, Humic, and Fulvic Acids as Representative Fractions of Various Land-Use Soils Maria Jerzykiewicz1, Agnieszka Grabusiewicz2, Jerzy Weber3 1 Faculty of Chemistry, University of Wrocław, Joliot−Curie 14, 50−383 Wrocław, Poland 2 Department of Chemical Sciences, University of Limerick, V94 T9PX Limerick, Ireland 3 Institute of Soil Science, Plant Nutrition and Environmental Protection, Wrocław University of Environmental and Life Sciences, Grunwaldzka 53 St., 50-357 Wrocław, Poland The subjects of the presented studies were humic acid and fulvic acid fractions, as well as humins obtained from soils of various types and uses. These included forest soils, fallow lands, and cultivated soils. The soil organic matter fractions from cultivated soils originated from various multi-year cultivation experiments in different parts of Europe. The starting materials, the soils, had different characteristics due to their different origins. Humic substances were extracted and subjected to various research methods. Apart from spectroscopic methods like NMR, EPR, ATR FTIR, and UV-Vis, standard chemical analyses like elemental composition and functional group titrations were performed. Principal Component Analysis (PCA) was performed to identify the factors that best differentiate the fractions under study. The subjects of the presented studies were humic acid and fulvic acid fractions, as well as humins obtained from soils of various types and uses. These included forest soils, fallow lands, and cultivated soils. The cultivated soils‘ organic matter fractions came from a number of multi-year cultivation studies conducted around Europe. The starting materials, the soils, had different characteristics due to their different origins. After being extracted, humic substances were exposed to a variety of study techniques. Apart from spectroscopic methods like NMR, EPR, ATR FTIR, and UV-Vis, standard chemical analyses like elemental composition and functional group titrations were carried out. Principal Component Analysis (PCA) was performed to identify the factors that best differentiate the fractions under study. Considering the results of various analyses, it is easy to see that the greatest influence on the structural characteristics of humic substances is the soil origin, not its use. For extracts from one area, radicals’ concentration could be 10x higher than from other areas, and ω (internal oxidation degree) for one group of samples could be negative while for others it is higher than 0. Only comparisons of results between samples from the same soils but with different uses were meaningful. Our results show that apart from the origin
IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 22 Analysis and Characterization Monday, 24 August 2026 / Hall B+C effect, the most influential factor was organic fertilizing. Most humins, humic, and fulvic acids extracted from soils where manure and manure with legumes were used had smaller concentrations of radicals. The physical and chemical characteristics of the soil and its organic components are influenced by organic fertilization and soil management, which are crucial in determining soil fertility. In contrast to the soil fertilized with NPK, the addition of manure had a substantial impact on the structure of SOM, increasing the quantity of aliphatic components. This change in composition implies that adding organic amendments can improve the soil‘s general health and nutrient retention. Therefore, using organic methods promotes sustainable agricultural systems in addition to increasing crop yields.
BOOK OF ABSTRACTS 23 IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 Monday, 24 August 2026 / Hall B+C Analysis and Characterization SL5 Characterization of Dissolved Organic Matter and its Relationship with Carbonaceous and Nitrogenous Disinfection By-Products Formation in Drinking Water Treatment Anne Kamau1, Peter Jarvis2, Bruce Jefferson3, John Haley4 1 Cranfield University, Cranfield Water Science Institute (CWSI), Cranfield, Bedfordshire, United Kingdom, MK 43 0 AL, A.Kamau@cranfield.ac.uk 2 Cranfield University, Cranfield Water Science Institute (CWSI), Cranfield, Bedfordshire, United Kingdom, MK 43 0 AL 3 Cranfield University, Cranfield Water Science Institute (CWSI), Cranfield, Bedfordshire, United Kingdom, MK 43 0 AL 4 UK Water Industry Research (UKWIR) Ltd, London, United Kingdom, SW1 0BH Dissolved organic matter (DOM) is a key indicator of drinking water source quality and a principal precursor of disinfection by-products (DBPs), yet bulk parameters often provide limited insight into DOM reactivity, particularly for emerging nitrogenous DBPs (NDBPs). This study presents an integrated assessment of DOM occurrence, characteristics and DBP formation potential (DBPFP) in raw and treated waters across multiple UK drinking water sources (lowland and upland surface water, groundwater) and associated water treatment works. Source water dissolved organic carbon (DOC) concentrations ranged from 0.30 – 9.35 mgL-1 C, with treated water DOC typically reduced by 2.9% - 80%, while dissolved organic nitrogen (DON) ranged from 16.4% – 22.0%, depending on the treatment processes employed. Excitation-emission (EEM) fluorescence spectroscopy coupled with fluorescence regional integration (FRI) was used to characterize DOM in water. The results showed variable distribution of humic-like (terrestrial and microbial) and proteinlike fractions among the different source water types. Treatment processes resulted in preferential removal of humic-like fluorescence, with reductions of 40% – 70% observed through conventional treatment processes, while protein-like components were more recalcitrant and, in some cases, relatively enriched following treatment. DBP formation potential experiments indicated trihalomethane formation potentials in the range of 11.86 – 86.34 µg.mgC⁻¹, haloacetic acid formation potentials of 38.58–260 µg. mgC⁻¹ as HAA9, haloacetonitriles formation potentials of 0.87–31.99 µg. mgC⁻¹ and haloacetamides formation potentials of 0.78–5.74 µg.mgC⁻¹ with higher DBPFP consistently associated with raw waters containing humic‑rich DOM. Strong correlations were observed between humic‑like fluorescence
IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 24 Analysis and Characterization Monday, 24 August 2026 / Hall B+C components and DBPFP (r ≈ 0.6–0.8), whereas correlations between NDBPFP and protein-like components were more variable among individual compounds. The combined use of occurrence data, fluorescence‑based DOM characterization, and DBPFP testing provided enhanced insight into DOM reactivity and DBP risk across treatment processes. These findings support the value of DOM fractionation as a complementary tool for understanding and managing DBP formation in drinking water production which will be essential for anticipating future DBP risks under climate‑driven changes in source water quality and increasing eutrophication pressure. Acknowledgement Funding for the work was provided by UK Water Industry Research Ltd (UKWIR) and the Engineering and Physical Sciences Research Council (EPSRC) as part of their support for the Water Infrastructure and Resilience (WIRe) Centre for Doctoral Training.
BOOK OF ABSTRACTS 25 IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 Monday, 24 August 2026 / Hall B+C Analysis and Characterization SL6 Fourier Transform Ion Cyclotron Resonance Mass Spectra of the Entire IHSS Standard and Reference Sample Collection E. Michael Perdue1, Mourad Harir2,3, Philippe Schmitt-Kopplin2,3 1 Georgia Institute of Technology, School of Earth and Atmospheric Sciences (Retired), 311 Ferst Drive, Atlanta, GA 30332-0340, USA, emperdue@comcast.net 2 Helmholtz Munich, Research Unit Analytical Biogeochemistry, Ingolstädter Landstraße 1, P.O. Box 1129, D-85758 Neuherberg, Germany 3 Technical University of Munich, Chair of Analytical Food Chemistry, Maximus-von-ImhofForum 2, 85354 Freising, Germany All available standard (19) and reference (15) samples of the International Humic Substances Society (IHSS) have been characterized by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS). The sample collection includes 15 fulvic acids (FA), 15 humic acids (HA), and four samples of natural organic matter (NOM). Ten samples were isolated from the Suwannee River (Georgia, USA). Ten samples were isolated from Elliott Soil (Illinois, USA). Five samples were isolated from Pahokee Peat (Florida, USA). One sample was isolated from Gascoyne Leonardite (North Dakota, USA). Eight samples were isolated from five sites in Antarctica (1), New Zealand (1), Norway (3), and the USA (3). Altogether, 15 samples were isolated from aquatic sources, and 19 samples were isolated from terrestrial sources. An FTICR-MS analysis of 33 of these IHSS samples was published recently [1]. Assuming that detected ions have charges of -1 or -2, mass lists of massto-charge (m/z) ratio and peak intensity were analyzed using CHOFIT3 software [2,3] to obtain all valid molecular formulae containing 0-3 N and 0-2 S, with a maximum allowed fitting error of 0.2 ppm. Possible formulae were ranked using several heuristic tools in CHOFIT3. The results that are presented here include only pairs of isotopologues (all C atoms are 12C in one formula and one of the C atoms is a 13C in the other formula). Furthermore, both formulae must have a heuristic rank of 1. Formulae meeting these criteria are referred to here as gold-standard formulae. Gold-standard formulae account for 9.6% of assigned formulae, and they account for 39.9% of assigned peak intensity. The majority of gold-standard formulae (85.5%) contain only C, H, and O (CHO formulae), with the remaining 14.5% also containing N and/or S (CHONS formulae). The average percentage of CHONS formulae is greater in samples from terrestrial sources (17.7%) than in samples from aquatic sources (10.5%).
IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 26 Analysis and Characterization Monday, 24 August 2026 / Hall B+C Collectively, the 34 IHSS samples contain 92126 gold-standard formulae. Some gold-standard formulae were found in multiple samples, so the entire data set can be reduced to 23168 unique gold-standard formulae. The presentation will examine the distribution of the unique gold-standard formulae among the IHSS samples, including the comparability of FA samples isolated from the same source at different times, the comparability between standard and reference samples from the same source, and between FA and HA samples isolated simultaneously. It also addresses how frequently unique CHO and CHONS formulae occur across multiple IHSS samples (e.g., 2, 5, or 10 samples) and whether CHO and CHONS formulae show similar probabilities of appearing across multiple samples. These and other comparative questions will be addressed in the presentation. In addition, general chemical differences among IHSS samples from aquatic and terrestrial sources will be discussed for four general subsets of molecular formulae: ReducedUnsaturated (O/C<=0.5, H/C<=1.0), Oxidized-Unsaturated (O/C>0.5, H/ C<=1.0), Oxidized-Saturated (O/C>0.5, H/C>1.0), and Reduced-Saturated (O/ C<=0.5, H/C>1.0). References 1. X. Zhang, M. Harir, J. Schick, M. Lucio, E. M. Perdue, P. Schmitt-Kopplin, Environmental Science & Technology 60 (2026) 7859. 2. E. M. Perdue, N. W. Green, Analytical Chemistry 87 (2015) 5079. 3. N. W. Green, E. M. Perdue, Analytical Chemistry 87 (2015) 5086. Acknowledgement All samples were provided by Prof. Paul Bloom, chair of the IHSS Standard and Reference Collection Committee.
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