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Publications in peer reviewed journals

27 Publications found
  • Acesulfame allows the tracing of multiple sources of wastewater and riverbank filtration

    Miguel Angel Marazuela, Giovanni Formentin, Klaus Erlmeier, Thilo Hofmann
    2023 - Environmental Pollution, 323: 121223


    Aquifers providing drinking water are increasingly threatened by emerging contaminants due to wastewater inputs from multiple sources. These inputs have to be identified, differentiated, and characterized to allow an accurate risk assessment and thus ensure the safety of drinking water through appropriate management. We hypothesize, that in climates with seasonal temperature variations, the sweetener acesulfame potassium (ACE) provides new pathways to study wastewater inputs to aquifers. Specifically, this study investigates the temperature-driven seasonal oscillation of ACE to assess multiple sources of wastewater inputs at a riverbank filtration site. ACE concentrations in the river water varied from 0.2 to 1 μg L−1 in the cold season (T < 10 °C) to 0–0.1 μg L−1 in the warm season (T > 10 °C), due to temperature-dependent biodegradation during wastewater treatment. This oscillating signal could be traced throughout the aquifer over distances up to 3250 m from two different infiltration sources. A transient numerical model of groundwater flow and ACE transport was calibrated over hydraulic heads and ACE concentrations, allowing the accurate calculation of mixing ratios, travel times, and flow-path directions for each of the two infiltration sources. The calculated travel time from the distant infiltration source was of 67 days, while that from the near source was of 20 days. The difference in travel times leads to different potential degradation of contaminants flowing into the aquifer from the river, thus demonstrating the importance of individually assessing the locations of riverbank infiltration. The calibrated ACE transport model allowed calculating transient mixing ratios, which confirmed the impact of river stage and groundwater levels on the mixing ratio of the original groundwater and the bank filtrate. Therefore, continuous monitoring of ACE concentrations can help to optimize the management of the water works with the aim to avoid collection of water with very short travel times, which has important regulative aspects. Our findings demonstrate the suitability of ACE as a transient tracer for identifying multiple sources of wastewater, including riverbank filtration sites affected by wastewater treatment plant effluents. ACE seasonal oscillation tracking thus provides a new tool to be used in climates with pronounced seasonal temperature variations to assess the origins of contamination in aquifers, with time and cost advantages over multi-tracer approaches.

  • Addressing Chemical Pollution in Biodiversity Research

    Gabriel Sigmund, Marlene Ågerstrand, Alexandre Antonelli, Thomas Backhaus, Tomas Brodin, Miriam L. Diamond, Walter R. Erdelen, David C. Evers, Thilo Hofmann, Thorsten Hueffer, Adelene Lai, Joao P. M. Torres, Leonie Mueller, Allison L. Perrigo, Matthias C. Rillig, Andreas Schaeffer, Martin Scheringer, Kristin Schirmer, Ahmed Tlili, Anna Soehl, Rita Triebskorn, Penny Vlahos, Colette vom Berg, Zhanyun Wang, Ksenia J. Groh
    2023 - Global Change Biology, 12: 3240-3255


    Climate change, biodiversity loss, and chemical pollution are planetary-scale emergencies requiring urgent mitigation actions. As these “triple crises” are deeply interlinked, they need to be tackled in an integrative manner. However, while climate change and biodiversity are often studied together, chemical pollution as a global change factor contributing to worldwide biodiversity loss has received much less attention in biodiversity research so far. Here, we review evidence showing that the multifaceted effects of anthropogenic chemicals in the environment are posing a growing threat to biodiversity and ecosystems. Therefore, failure to account for pollution effects may significantly undermine the success of biodiversity protection efforts. We argue that progress in understanding and counteracting the negative impact of chemical pollution on biodiversity requires collective efforts of scientists from different disciplines, including but not limited to ecology, ecotoxicology, and environmental chemistry. Importantly, recent developments in these fields have now enabled comprehensive studies that could efficiently address the manifold interactions between chemicals and ecosystems. Based on their experience with intricate studies of biodiversity, ecologists are well equipped to embrace the additional challenge of chemical complexity through interdisciplinary collaborations. This offers a unique opportunity to jointly advance a seminal frontier in pollution ecology and facilitate the development of innovative solutions for environmental protection.

  • Analytical strategies to measure gadolinium as a wastewater marker in surface and groundwater systems

    Miguel Angel Marazuela, Martin Stockhausen, Thilo Hofmann
    2023 - MethodsX, 10: 101965


    The increasing use of gadolinium (Gd)-based contrast agents in magnetic resonance imaging and the recalcitrant behavior of Gd during municipal wastewater treatment have led to increased concentrations of the tracer in aquatic environments. These anthropogenic Gd emissions to wastewater and, subsequently, to surface and groundwater systems can be exploited to calculate groundwater travel times and mixing ratios, identify wastewater inputs, and calibrate groundwater models. However, analytical complexity, costs, and the time needed to directly measure anthropogenic inputs hinder the practical use of Gd. While direct measurements with inductively coupled plasma-mass spectrometry (ICP-MS) are highly efficient and feasible, only total Gd can be detected with this approach. In unknown hydrogeological systems, the differentiation between total, anthropogenic, and geogenic Gd by interpolating rare earth element patterns requires complex sample pre-treatment and pre-concentration. Direct measurements of Gd can be obtained using anion-exchange chromatography coupled to ICP-MS but the limit of quantification will be higher. Here we provide guidelines for selecting the optimal method for the analysis of Gd as a wastewater tracer in surface-groundwater systems.

    • The cost-effectiveness of existing analytical strategies to measure Gd when used as a wastewater tracer in surface-groundwater systems is addressed
    • A novel analytical strategy for direct determination of total Gd is presented


  • Benchmarking biochar with activated carbon for immobilizing leachable PAH and heterocyclic PAH in contaminated soils

    Carlotta Carlini, Sampriti Chaudhuri, Oliver Mann, Daniel Tomsik, Thorsten Hüffer, Nicolas Greggio, Diego Marazza, Thilo Hofmann, Gabriel Sigmund
    2023 - Environmental Pollution, 325: 121417


    Remediation of residually contaminated soils remains a widespread problem. Biochar can immobilize polycyclic aromatic hydrocarbons (PAH). However, studies on its ability to immobilize PAH and N, S, and O substituted PAH (hetero-PAH) in real soils, and benchmarking with commercial activated carbon are missing. Here, we compared the ability of pristine biochar (BC), steam-activated biochar (SABC), and commercial activated carbon (AC) to immobilize PAH and hetero-PAH. The three carbons were tested on soils from four different contaminated sites in Austria. Different amendment rates (w/w) of the carbons were investigated (BC: 1.0, 2.5, and 5%; SABC: 0.5, 1.0, and 2.0%; AC: 1%) in batch experiments to cover meaningful ranges in relation to their performance. SABC performed better than AC, removing at least 80% PAH with the lowest application rate of 0.5%, and achieving a complete removal at an application rate of 1.0%. BC performed slightly worse but still acceptable in residually contaminated soils (40 and 100% removal at 1 and 5% amendment, respectively). The ability of BC and SABC to immobilize PAH decreased as the PAH-molar volume increased. PAH with three or more rings were preferentially removed by AC compared to SABC or BC. This can be explained by the difference in pore size distribution of the carbons which could limit the accessibility of PAH and hetero-PAH to reach sorption sites for π- π electron donor-acceptor interactions, which drive PAH and hetero-PAH sorption to carbons. Column percolation tests confirmed the results obtained in batch tests, indicating, that decisions for soil remediation can be derived from simpler batch experiments. In soil samples with 1% BC, a reduction of over 90% in the total concentration of PAH in the leached water was observed. Overall, BC and SABC were demonstrated to be valid substitutes for AC for stabilizing residually contaminated soils.

  • Chemical characteristics of wildfire ash across the globe and their environmental and socio-economic implications

    Carmen Sanchez-García, Cristina Santín, Jonay Neris, Gabriel Sigmund, Xosé Lois Otero, J. Manley, Gil Gonzalez-Rodríguez, Claire M. Belcher, Artemi Cerda, Abbey L. Marcotte, Sheila F. Murphy, Charles C. Rhoades, Gary Sheridan, Tercia Strydom, Peter R. Robichaud, Stefan H. Doerr
    2023 - Environment International, 178: 108065


    The mobilisation of potentially harmful chemical constituents in wildfire ash can be a major consequence of wildfires, posing widespread societal risks. Knowledge of wildfire ash chemical composition is crucial to anticipate and mitigate these risks.

    Here we present a comprehensive dataset on the chemical characteristics of a wide range of wildfire ashes (42 types and a total of 148 samples) from wildfires across the globe and examine their potential societal and environmental implications. An extensive review of studies analysing chemical composition in ash was also performed to complement and compare our ash dataset.

    Most ashes in our dataset had an alkaline reaction (mean pH 8.8, ranging between 6 and 11.2). Important constituents of wildfire ash were organic carbon (mean: 204 g kg−1), calcium, aluminium, and iron (mean: 47.9, 17.9 and 17.1 g kg−1). Mean nitrogen and phosphorus ranged between 1 and 25 g kg−1, and between 0.2 and 9.9 g kg−1, respectively. The largest concentrations of metals of concern for human and ecosystem health were observed for manganese (mean: 1488 mg kg−1; three ecosystems > 1000 mg kg−1), zinc (mean: 181 mg kg−1; two ecosystems > 500 mg kg−1) and lead (mean: 66.9 mg kg−1; two ecosystems > 200 mg kg−1). Burn severity and sampling timing were key factors influencing ash chemical characteristics like pH, carbon and nitrogen concentrations. The highest readily dissolvable fractions (as a % of ash dry weight) in water were observed for sodium (18 %) and magnesium (11.4 %). Although concentrations of elements of concern were very close to, or exceeded international contamination standards in some ashes, the actual effect of ash will depend on factors like ash loads and the dilution into environmental matrices such as water, soil and sediment. Our approach can serve as an initial methodological standardisation of wildfire ash sampling and chemical analysis protocols.

  • Copper Bioreduction and Nanoparticle Synthesis by an Enrichment Culture from a Former Copper Mine

    Richard Kimber, Gretta Elizondo, Klaudia Jedyka, Christopher Boothman, Rongsheng Cai, Heath Bagshaw, Sarah J. Haigh, Victoria S. Coker, Jonathan R. Lloyd
    2023 - Environ. Microbiol., 12: 3139-3150


    Microorganisms can facilitate the reduction of Cu2+, altering its speciation and mobility in environmental systems and producing Cu-based nanoparticles with useful catalytic properties. However, only a few model organisms have been studied in relation to Cu2+ bioreduction and little work has been carried out on microbes from Cu-contaminated environments. This study aimed to enrich for Cu-resistant microbes from a Cu-contaminated soil and explore their potential to facilitate Cu2+ reduction and biomineralisation from solution. We show that an enrichment grown in a Cu-amended medium, dominated by species closely related to Geothrix fermentans, Azospira restricta and Cellulomonas oligotrophica, can reduce Cu2+ with subsequent precipitation of Cu nanoparticles. Characterisation of the nanoparticles with (scanning) transmission electron microscopy, energy-dispersive x-ray spectroscopy and electron energy loss spectroscopy supports the presence of both metallic Cu(0) and S-rich Cu(I) nanoparticles. This study provides new insights into the diversity of microorganisms capable of facilitating copper reduction and highlights the potential for the formation of distinct nanoparticle phases resulting from bioreduction or biomineralisation reactions. The implications of these findings for the biogeochemical cycling of copper and the potential biotechnological synthesis of commercially useful copper nanoparticles are discussed.

  • Eco-Corona Dictates Mobility of Nanoplastics in Saturated Porous Media: The Critical Role of Preferential Binding of Macromolecules

    Meiling Zhu, Zhanhua Zhang, Tong Zhang, Thilo Hofmann, Wei Chen
    2023 - Environ. Sci. Technol., 57: 331-339


    Nanoplastics are an increasing environmental concern. In aquatic environments, nanoplastics will acquire an eco-corona by interacting with macromolecules (e.g., humic substances and extracellular polymeric substances (EPS)). Here, we show that the properties of the eco-corona and, consequently, its ability to enhance the transport of nanoplastics vary significantly with the surface functionality of nanoplastics and sources of macromolecules. The eco-corona derived from the EPS of Gram-negative Escherichia coli MG1655 enhances the transport of polystyrene (PS) nanospheres in saturated porous media to a much greater extent than the eco-corona derived from soil humic acid and fulvic acid. In comparison, the eco-corona from all three sources significantly enhance the transport of carboxylated PS (HOOC-PS). We show that the eco-corona inhibits the deposition of the two types of nanoplastics to the porous media mainly via steric repulsion. Accordingly, an eco-corona consisting of a higher mass of larger-sized macromolecules is generally more effective in enhancing transport. Notably, HOOC-PS tends to acquire macromolecules of lower hydrophobicity than PS. The more disordered and flexible structures of such macromolecules may result in greater elastic repulsion between the nanoplastics and sand grains and, consequently, greater transport enhancement. The findings of this study highlight the critical role of eco-corona formation in regulating the mobility of nanoplastics, as well as the complexity of this process.

  • Effect of Competing Metals and Humic Substances on Uranium Mobilization from Noncrystalline U(IV) Induced by Anthropogenic and Biogenic Ligands

    Kyle J. Chardi, Walter D. C. Schenkeveld, Naresh Kumar, Daniel E. Giammar, Stephan M. Kraemer
    2023 - Environ. Sci. Technol., 42: 16006–16015


    Anthropogenic and biogenic ligands may mobilize uranium (U) from tetravalent U (U(IV)) phases in the subsurface, especially from labile noncrystalline U(IV). The rate and extent of U(IV) mobilization are affected by geochemical processes. Competing metals and humic substances may play a decisive role in U mobilization by anthropogenic and biogenic ligands. A structurally diverse set of anthropogenic and biogenic ligands was selected for assessing the effect of the aforementioned processes on U mobilization from noncrystalline U(IV), including 2,6-pyridinedicarboxylic acid (DPA), citrate, N,N′-di(2-hydroxybenzyl)ethylene-diamine-N,N′-diacetic acid (HBED), and desferrioxamine B (DFOB). All experiments were performed under anoxic conditions at pH 7.0. The effect of competing metals (Ca, Fe(III), and Zn) on ligand-induced U mobilization depended on the particular metal–ligand combination ranging from nearly complete U mobilization inhibition (e.g., Ca-citrate) to no apparent inhibitory effects or acceleration of U mobilization (e.g., Fe(III)-citrate). Humic substances (Suwannee River humic acid and fulvic acid) were tested across a range of concentrations either separately or combined with the aforementioned ligands. Humic substances alone mobilized appreciable U and also enhanced U mobilization in the presence of anthropogenic or biogenic ligands. These findings illustrate the complex influence of competing metals and humic substances on U mobilization by anthropogenic and biogenic ligands in the environment.

  • Environmental factors strongly influence the leaching of di(2-ethylhexyl) phthalate from polyvinyl chloride microplastics

    Charlotte Henkel, Jonas Lamprecht, Thorsten Hüffer, Thilo Hofmann
    2023 - Water Research, 242: 120235


    Phthalic acid esters (phthalates) are an important group of additives (plasticizers) to ensure the flexibility and stability especially of polyvinyl chloride (PVC) and to enable its processing. However, phthalates like di(2-ethylhexyl) phthalate (DEHP) are harmful for aquatic organisms due to their endocrine disrupting effects and toxicity. For the assessment of exposure concentrations, thorough understanding of leaching kinetics of phthalates from PVC (micro-) plastics into aqueous environments is necessary. This study investigates how environmental factors influence the leaching of phthalates from PVC microplastics into aquatic systems. The leaching of phthalates from PVC microplastics into aqueous media is limited by aqueous boundary layer diffusion (ABLD) and thus, process-specific parameters can be affected by environmental factors such as salinity and the flow conditions. We conducted batch leaching experiments to assess the influence of salinity and flow conditions (turbulence) on the leaching of DEHP from PVC microplastics into aqueous media. DEHP is salted out with increasing salinity of the solution and a salting-out coefficient for DEHP of 0.46 was determined. The partitioning coefficient of DEHP between PVC and water KPVC/W increased with increasing salinity from 108.52 L kg−1 in a 1 mM KCl solution to 108.75 L kg−1 in artificial seawater thereby slowing down leaching. Increasing flow velocities led to higher leaching rates because the ABL thickness decreased from 1315 µm at 0 rpm shaking speed (no-flow conditions) to 38.4 µm at 125 rpm (turbulent conditions). Compared to salinity, turbulence had a more pronounced effect on leaching. Increasing the flow velocity led to a 35-fold decrease in the leaching rate, while increasing salinity led to a 2-fold increase. By calculating specific leaching times, that is, leaching half-lives (t1/2), time frames for leaching in different aquatic systems such as rivers and the ocean were determined. Given ABLD-limited leaching, DEHP is leached faster from PVC microplastics in rivers (t1/2 > 49 years) than in the ocean (t1/2 > 398 years). In both systems, PVC microplastics are a long-term source of phthalates.

  • Environmental, Biomedical, and Industrial Applications of Biogenic Magnetite Nanoparticles

    Lucía Gandarias, Richard Kimber, Georges Ona-Nguema
    2023 - Elements, 4: 228-233


    Magnetite is the most abundant magnetic iron mineral on the Earth’s surface. Its formation in natural ecosystems is mainly due to microbial activity. Microbially synthesized magnetite, commonly called “biogenic magnetite,” has many beneficial properties for a wide range of environmental and commercial applications. Its high surface reactivity facilitates interactions with (in)organic pollutants in anthropic and natural ecosystems, as well as with reagents in industrial catalysis. Due to its magnetic properties and good biocompatibility, biogenic magnetite is also well suited for biomedical applications such as cancer treatment or drug delivery. Biomineralization of magnetite offers an inexpensive and sustainable method for the production of this highly functional material. Moreover, this biomineralization process results in a biomolecule coating of the magnetite, making it highly amenable to further functionalization. This chapter reviews the application of biogenic magnetite across environmental, medical, and industrial settings. Existing challenges and future opportunities in these applications are also discussed.

  • Fragmentation and Mineralization of a Compostable Aromatic–Aliphatic Polyester during Industrial Composting

    Wendel Wohlleben, Markus Rückel, Lars Meyer, Patricia Pfohl, Glauco Battagliarin, Thorsten Hüffer, Michael Zumstein, Thilo Hofmann
    2023 - Environ. Sci. Technol., 8: 698-704


    Compostable plastics support the separate collection of organic waste. However, there are concerns that the fragments generated during disintegration might not fully biodegrade and leave persistent microplastic in compost. We spiked particles of an aromatic–aliphatic polyester containing polylactide into compost and then tracked disintegration under industrial composting conditions. We compared the yields against polyethylene. The validity of the extraction protocol and complementary microscopic methods (μ-Raman and fluorescence) was assessed by blank controls, spike controls, and prelabeled plastics. Fragments of 25–75 μm size represented the most pronounced peak of interim fragmentation, which was reached already after 1 week of industrial composting. Larger sizes peaked earlier, while smaller sizes peaked later and remained less frequent. For particles of all sizes, count and mass decreased to blank level when 90% of the polymer carbon were transformed into CO2. Gel permeation chromatography (GPC) analysis suggested depolymerization as the main driving force for disintegration. A transient shift of the particle composition to a lower percentage of polylactide was observed. Plastic fragmentation during biodegradation is the expected route for decomposing, but no accumulation of particulate fragments of any size was observed.

  • Generation of Reproducible Model Freshwater Particulate Matter Analogues to Study the Interaction with Particulate Contaminants.

    Helene Walch, Antonia Praetorius, Frank von der Kammer, Thilo Hofmann
    2023 - Water Research, 229: 119385


    Aquatic fate models and risk assessment require experimental information on the potential of contaminants to interact with riverine suspended particulate matter (SPM). While for dissolved contaminants partition or sorption coefficients are used, the underlying assumption of chemical equilibrium is invalid for particulate contaminants, such as engineered nanomaterials, incidental nanoparticles, micro- or nanoplastics. Their interactions with SPM are governed by physicochemical forces between contaminant-particle and SPM surfaces. The availability of a standard SPM material is thus highly relevant for the development of reproducible test systems to evaluate the fate of particulate contaminants in aquatic systems. Finding suitable SPM analogues, however, is challenging considering the complex composition of natural SPM, which features floc-like structures comprising minerals and organic components from the molecular to the microorganism level. Complex composition comes with a heterogeneity in physicochemical surface properties, that cannot be neglected. We developed a procedure to generate SPM analogue flocs from components selected to represent the most abundant and crucial constituents of natural riverine SPM, and the process-relevant SPM surface characteristics regarding interactions with particulate contaminants. Four components, i.e., illite, hematite, quartz and tryptophan, combined at environmentally realistic mass-ratios, were associated to complex flocs. Flocculation was reproducible regarding floc size and fractal dimension, and multiple tests on floc resilience towards physical impacts (agitation, sedimentation-storage-resuspension, dilution) and hydrochemical changes (pH, electrolytes, dissolved organic matter concentration) confirmed their robustness. These reproducible, ready-to-use SPM analogue flocs will strongly support future research on emerging particulate contaminants.

  • Integrated Data-Driven Cross-Disciplinary Framework to Prevent Chemical Water Pollution

    Mohamed Ateia, Gabriel Sigmund, Michael J. Bentel, John W. Washington, Adelene Lai, Nathaniel H. Merrill, Zhanyun Wang
    2023 - One Earth, 8: 952-963


    Access to a clean and healthy environment is a human right and a prerequisite for maintaining a sustainable ecosystem. Experts across domains along the chemical life cycle have traditionally operated in isolation, leading to limited connectivity between upstream chemical innovation to downstream development of water-treatment technologies. This fragmented and historically reactive approach to managing emerging contaminants has resulted in significant externalized societal costs. Herein, we propose an integrated data-driven framework to foster proactive action across domains to effectively address chemical water pollution. By implementing this integrated framework, it will not only enhance the capabilities of experts in their respective fields but also create opportunities for novel approaches that yield co-benefits across multiple domains. To successfully operationalize the integrated framework, several concerted efforts are warranted, including adopting open and FAIR (findable, accessible, interoperable, and reusable) data practices, developing common knowledge bases/platforms, and staying vigilant against new substance “properties” of concern.

  • Iron Nitride Nanoparticles for Rapid Dechlorination of Mixed Chlorinated Ethene Contamination

    Miroslav Brumovský, Vesna Micić, Jana Oborná, Jan Filip, Thilo Hofmann, Daniel Tunega
    2023 - Journal of Hazardous Materials, 442: 129988


    Sulfidation and, more recently, nitriding have been recognized as promising modifications to enhance the selectivity of nanoscale zero-valent iron (nZVI) particles for trichloroethene (TCE). Herein, we investigated the performance of iron nitride (FexN) nanoparticles in the removal of a broader range of chlorinated ethenes (CEs), including tetrachloroethene (PCE), cis-1,2-dichloroethene (cis-DCE), and their mixture with TCE, and compared it to the performance of sulfidated nZVI (S-nZVI) prepared from the same precursor nZVI. Two distinct types of iron nitride (FexN) nanoparticles, containing γ′-Fe4N and ε-Fe2–3N phases, exhibited substantially higher PCE and cis-DCE dechlorination rates compared to S-nZVI. A similar effect was observed with a CE mixture, which was completely dechlorinated by both types of FexN nanoparticles within 10 days, whereas S-nZVI was able to remove only about half of the amount, most of which being TCE. Density functional theory calculations further revealed that the cleavage of the first C–Cl bond was the rate-limiting step for all CEs dechlorinated on the γ′-Fe4N(001) surface, with the reaction barriers of PCE and cis-DCE being 29.9, and 40.8 kJ mol–1, respectively. FexN nanoparticles proved to be highly effective in the remediation of PCE, cis-DCE, and mixed CE contamination.

  • Is sorption technology fit for the removal of persistent and mobile organic contaminants from water?

    Benedikt M. Aumeier, Anett Georgi, Navid Saeidi, Gabriel Sigmund
    2023 - Science of The Total Environment, 880: 163343


    Persistent, Mobile, and Toxic (PMT) and very persistent and very mobile (vPvM) substances are a growing threat to water security and safety. Many of these substances are distinctively different from other more traditional contaminants in terms of their charge, polarity, and aromaticity. This results in distinctively different sorption affinities towards traditional sorbents such as activated carbon. Additionally, an increasing awareness on the environmental impact and carbon footprint of sorption technologies puts some of the more energy-intensive practices in water treatment into question. Commonly used approaches may thus need to be readjusted to become fit for purpose to remove some of the more challenging PMT and vPvM substances, including for example short chained per- and polyfluoroalkyl substances (PFAS). We here critically review the interactions that drive sorption of organic compounds to activated carbon and related sorbent materials and identify opportunities and limitations of tailoring activated carbon for PMT and vPvM removal. Other less traditional sorbent materials, including ion exchange resins, modified cyclodextrins, zeolites and metal-organic frameworks are then discussed for potential alternative or complementary use in water treatment scenarios. Sorbent regeneration approaches are evaluated in terms of their potential, considering reusability, potential for on-site regeneration, and potential for local production. In this context, we also discuss the benefits of coupling sorption to destructive technologies or to other separation technologies. Finally, we sketch out possible future trends in the evolution of sorption technologies for PMT and vPvM removal from water.

  • Isolation of Carbon Black from Soils by Dispersion for Analysis: Quantitation and Characterization by Field Flow Fractionation Techniques

    Lorenzo Sanjuan-Navarro, Aaron Boughbina-Portolés, Yolanda Moliner-Martinéz, Frank von der Kammer, Pilar Campíns-Falcó
    2023 - ACS Omega, 8: 34795−34804


    In the present work, a procedure based on a dispersive medium for carbon black (CB) isolation from soil samples for analysis was proposed for the first time. Polymeric and biological dispersants and a sequential use of both dispersants were assayed. Asymmetrical flow field flow fractionation with dynamic light scattering detector (AF4-DLS) and sedimentation field flow fractionation with multi-angle light scattering detector (SdF3-MALS) were used for CB quantitation and characterization in the achieved dispersions. Soil samples contaminated with CB were processed, and CB isolation depended on the solid size distribution and composition and dispersant nature. More quantitative isolations were achieved for the four soils treated by the biological dispersant. As the organic matter percentage is higher in soil, the CB isolation was better, varying between 75 and 99% with standard deviation (s) ⩽ 2% for all soils. A soil contaminated with a CB-based pigment paste was analyzed, achieving (99 ± 2)% expressed as expanded uncertainty (K = 2) of dispersive isolation by the biological dispersant, and the sampling was scaled to 250 g of soil with positive results. The procedure was completed by CB recovery to obtain a solid residue able to be reused if necessary. For the filter-aided recovery step, different membranes (fiberglass, nylon, and Teflon) with a pore size between 0.1 and 5 μm were tested. The quantitation of the CB retained in the filter was measured by diffuse reflectance spectroscopy. Teflon (0.10 μm) provided better results for CB recovery, and its re-dispersion was also studied with suitable results. Determination of CB from the filters by diffuse reflectance spectrometry provided the same results than AF4 for CB dispersions.

  • Key Principles for the Intergovernmental Science–Policy Panel on Chemicals and Waste

    Marlene Ågerstrand, Kenneth Arinaitwe, Thomas Backhaus, Ricardo O. Barra, Miriam L. Diamond, Joan O. Grimalt, Ksenia Groh, Faith Kandie, Perihan Binnur Kurt-Karakus, Robert J. Letcher, Rainer Lohmann, Rodrigo O. Meire, Temilola Oluseyi, Andreas Schäffer, Mochamad Septiono, Gabriel Sigmund, Anna Soehl, Temitope O. Sogbanmu, Noriyuki Suzuki, Marta Venier, Penny Vlahos, Martin Scheringer
    2023 - Environ. Sci. Technol., 6: 2205–2208


    In 2021, the United Nations Environment Programme (UNEP) recognized chemical pollution as a planetary crisis tantamount to climate change and biodiversity decline. In an important next step, the international community agreed in March 2022 on establishing an independent, intergovernmental science–policy panel on chemicals, waste, and pollution prevention (hereafter termed “the Panel”). This Panel will take its place among two other intergovernmental bodies, the Intergovernmental Panel on Climate Change (IPCC) and the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). Now is a crucial time for establishing the Panel, following a process facilitated by UNEP to negotiate the Panel’s scope, functions, and institutional design, with the ambition to formally establish the Panel in 2024.
    As a group of international scientists working on chemical pollution, we applaud this milestone of progress to initiate the establishment of a panel for chemicals, waste, and pollution prevention. At the beginning of the negotiating process, we would like to highlight the following 10 critical aspects for consideration in determining the settings of the Panel.


  • Plastics can be used more sustainably in agriculture

    Thilo Hofmann, Subhasis Ghoshal, Nathalie Tufenkji, Jan Franklin Adamowski, Stéphane Bayen, Qiqing Chen, Philip Demokritou, Markus Flury, Thorsten Hüffer, Natalia P. Ivleva, Rong Ji, Richard L. Leask, Milan Maric, Denise M. Mitrano, Michael Sander, Sabine Pahl, Matthias C. Rillig, Tony R. Walker, Jason C. White, Kevin J. Wilkinson
    2023 - Nature Communications Earth & Environment, 4: 332


    Plastics have become an integral component in agricultural production as mulch films, nets, storage bins and in many other applications, but their widespread use has led to the accumulation of large quantities in soils. Rational use and reduction, collection, reuse, and innovative recycling are key measures to curb plastic pollution from agriculture. Plastics that cannot be collected after use must be biodegradable in an environmentally benign manner. Harmful plastic additives must be replaced with safer alternatives to reduce toxicity burdens and included in the ongoing negotiations surrounding the United Nations Plastics Treaty. Although full substitution of plastics is currently not possible without increasing the overall environmental footprint and jeopardizing food security, alternatives with smaller environmental impacts should be used and endorsed within a clear socio-economic framework. Better monitoring and reporting, technical innovation, education and training, and social and economic incentives are imperative to promote more sustainable use of plastics in agriculture.

  • Policy options to account for multiple chemical pollutants threatening biodiversity

    Leonie Katharina Mueller, Marlene Ågerstrand, Thomas Backhaus, Miriam Diamond, Walter Erdelen, David Evers, Ksenia Groh, Martin Scheringer, Gabriel Sigmund, Zhanyun Wang, Andreas Schäffer
    2023 - Environmental Science: Advances, 2: 151-161


    Chemical pollution poses a threat to biodiversity on a global scale. This has been acknowledged in the Post-2020 Biological Diversity Framework which proposes to regulate the release of chemicals to the environment and names specific indicators focusing on pesticides, nutrients and plastic waste. We fully endorse the inclusion of these substances but argue that in order to protect biodiversity from hazardous chemicals, the scope of Target 7 should feature other groups of pollutants with potential to contribute to biodiversity loss. We propose the inclusion of non-agricultural biocides, per- and polyfluoroalkyl substances (PFASs), toxic metal(loid)s, and endocrine disrupting chemcials (EDCs). Furthermore, data on emerging pollutants (e.g., rare earth elements, industrial chemicals, liquid crystal monomers, pharmaceuticals, personal care products) need to be regularly scanned and these pollutants added to Target 7 in case of biodiversity risk. We suggest to amend Target 7 to postulate the aim for the overall reduction of chemical production and emissions, as well as the addition of the described substance groups of high concern to biodiversity for discussion and implementation in the Post-2020 Biodiversity Framework. We further elaborate on different strategies for the reduction of emissions of hazardous chemicals through chemical simplification and grouping, reduction of chemicals with non-essential use, and innovative synthesis strategies (“benign by design”). In this context the full life cycle of chemicals, i.e., production, use, end of life needs to be considered. Lastly, we propose to set up data inventories that transparently inform about production, transport and emissions of chemicals in cooperation with industry, that can serve as basis for indicators related to monitoring the effectiveness of the goals set under Target 7.

  • Results of an interlaboratory comparison for characterization of Pt nanoparticles using singleparticle ICP-TOFMS

    Lyndsey Hendriks, Robert Brünjes, Sara Taskula, Jovana Kocic, Bodo Hattendorf, Garret Bland, Gregory Lowry, Eduardo Bolea-Fernandez, Frank Vanhaecke, Jingjing Wang, Mohammed Baalousha, Marcus von der Au, Björn Meermann, Timothy Ronald Holbrook, Stephan Wagner, Stasia Harycki, Alexander Gundlach-Graham, Frank von der Kammer
    2023 - Nanoscale, 15: 11268-11279


    This study describes an interlaboratory comparison (ILC) among nine (9) laboratories to evaluate and validate
    the standard operation procedure (SOP) for single-particle (sp) ICP-TOFMS developed within the
    context of the Horizon 2020 project ACEnano. The ILC was based on the characterization of two different Pt
    nanoparticle (NP) suspensions in terms of particle mass, particle number concentration, and isotopic composition.
    The two Pt NP suspensions were measured using icpTOF instruments (TOFWERK AG, Switzerland). Two Pt NP samples were characterized and mass equivalent spherical sizes (MESSs) of 40.4 ± 7 nm and 58.8 ± 8 nm were obtained, respectively. MESSs showed <16% relative standard deviation (RSD) among all participating labs and <4% RSD after exclusion of the two outliers. A good agreement was achieved between the different participating laboratories regarding particle mass, but the particle number concentration results were more scattered, with <53% RSD among all laboratories, which is consistent with results from previous ILC studies conducted using ICP-MS instrumentation equipped with a sequential mass spectrometer. Additionally, the capabilities of sp-ICP-TOFMS to determine masses on a particle basis are discussed with respect to the potential for particle density determination. Finally, because quasi-simultaneous multi-isotope and multielement determinations are a strength of ICP-TOFMS instrumentation, the precision and trueness of isotope ratio determinations were assessed. The average of 1000 measured particles yielded a precision of below ±1% for intensity ratios of the most abundant Pt isotopes, i.e. 194Pt and 195Pt, while the accuracy of isotope ratios with the lower abundant isotopes was limited by counting statistics.

  • Seasonal biodegradation of the artificial sweetener acesulfame enhances its use as a transient wastewater tracer

    Miguel Angel Marazuela, Giovanni Formentin, Klaus Erlmeier, Thilo Hofmann
    2023 - Water Research, 232: 119670


    The persistence of the artificial sweetener acesulfame potassium (ACE) during wastewater treatment and subsequently in the aquatic environment has made it a widely used tracer of wastewater inputs to both surface water and groundwater. However, the recently observed biodegradation of ACE during wastewater treatment has questioned the validity of this application. In this study, we assessed the use of ACE not only as a marker of wastewater, but also as a transient wastewater tracer that allows both the calculation of mixing ratios and travel times through the aquifer as well as the calibration of transient groundwater flow and mass transport models. Our analysis was based on data obtained in a nearly 8-year river water and groundwater sampling campaign along a confirmed wastewater-receiving riverbank filtration site located close to a drinking water supply system. We provide evidence that temperature controls ACE concentration and thus its seasonal oscillation. River water data showed that ACE loads decreased from 1.5–4 mg·s−1 in the cold season (December to June; T<10 °C) to 0–0.5 mg·s−1 in the warm season (July to November; T>10 °C). This seasonal variability of >600% was detectable in the aquifer and preserved >3 km, with ACE concentrations oscillating between <LOQ in the warm season up to 1 μg·L−1 in the cold season. The large seasonal variation in ACE concentrations during wastewater treatment, compared to the other sweeteners (sucralose, cyclamate, and saccharin) and chloride enables its use as a transient tracer of wastewater inflows and riverbank filtration. In addition, the arrival time of the ACE concentration peak can be used to estimate groundwater flow velocity and mixing ratios, thereby demonstrating its potential in the calibration of groundwater numerical models.

  • Small biochar particles hardly disintegrate under cryo-stress

    Gabriel Sigmund, Andrea Schmid, Hans-Peter Schmidt, Nikolas Hagemann, Thomas D. Bucheli, Thilo Hofmann
    2023 - Geoderma, 430: 116326


    Physical disintegration of biochar has been postulated to determine the persistence and mobility in soil of this recalcitrant carbon pool. Therein, freeze–thaw cycling can induce substantial physical stress to biochars. We here investigated the physical disintegration and subsequent mobilisation of five different biochars under “realistic worst-case scenarios” in a laboratory soil column setup as well as in shaking and sonication batch experiments. The mobilization of carbon from biochar particles (0.25–1 mm) was investigated in the absence of clay at a pH of 6.3 with and without 80 freeze–thaw cycles. The small biochar particles used in this study did not strongly disintegrate after freeze–thaw cycling, possibly because of freezing point depression in biochar micropores. Our results in comparison with findings in literature suggest that freeze–thaw-induced physical disintegration of biochar is a process more pronounced for large biochar particles containing substantial meso- and macropores. Biochars with larger ash fractions disintegrated more, presumably because of the ash-associated formation of unstable cavities within the biochar. Physical stability of biochars produced from the same feedstock at different pyrolysis temperatures decreased with increasing aromaticity, which may be linked to a higher rigidity of more aromatic structures. Moisture content in the soil increased carbon mobilization from biochar more than physical stress such as freeze–thaw cycling. The physical disintegration of biochar and subsequent mobilization of micro-and nanosized carbon should thus be considered of minor relevance and is often not a driving factor for biochar stability in soil.

  • Stromatolitic carbonates from the Middle Miocene of the western Pannonian Basin reflect trace metal availability in microbial habitats during the Badenian Salinity Crisis

    Sebastian Viehmann, Robert Kujawa, Simon V. Hohl, Nathalie Tepe, Alexandra S. Rodler, Thilo Hofmann, Erich Draganits
    2023 - Chemical Geology, 618: 121301


    Stromatolitic carbonates of the Middle Miocene Oberpullendorf Basin (Austria) provide a great opportunity to study the evolution of microbial habitats under extreme environmental changes during the Badenian (Langhian and early Serravallian) Salinity Crisis. We here present the first geochemical data for Badenian stromatolites and show in a combined approach using major, trace element, and C – O isotope compositions obtained in individual stromatolitic carbonate laminae that short-term variations of palaeo-environmental conditions within the Oberpullendorf Basin coincide with individual microbialite morphologies.

    The studied carbonates were affected by both detrital contamination and post-depositional alteration processes to different degrees. While fluid-mobile elements show clear evidence for post-depositional alteration processes, the rare earth element and yttrium (REY) as well as bio-essential element (Fe, Mn, Co, Zn, Mo, W) compositions of the carbonates remained unaffected. Stromatolitic carbonates that are devoid of detrital contamination (< 300 ppm Al) show typical shale-normalized seawater-like rare earth element and yttrium (REYSN) patterns with positive LaSN, GdSN anomalies, super-chondritic Y/Ho ratios, and heavy over light REYSN enrichments in the lower stromatolite units. These features suggest an open ocean seawater influenced depositional setting at the north-western margin of the Paratethys Sea. Stratigraphically upwards, pure stromatolitic carbonates show suppressed seawater-like REYSN signatures that argue for the development of a (semi)closed lagoon with restricted access to the open sea. Seawater-like REYSN patterns in the uppermost part resemble a reappearance of open marine environmental conditions. Interestingly, geochemical data of the upper part of the section contradict the ambient fossil record, showing the urge for future interdisciplinary approaches targeting the understanding and interplay of geochemistry, palaeontology, and geomicrobiology in modern and ancient microbial habitats. Enrichment factors of bio-essential trace elements that are either used as co-factors in metalloenzymes or metal-activated enzymes in biochemical reactions can be directly linked to the reconstructed environmental conditions: Sufficient element availability is ensured during marine conditions in the lower and uppermost stratigraphic sections; in contrast, continuous decreasing element availability of these elements is directly related to the temporary development of a (semi)closed lagoon.

  • The Challenge of Interdisciplinarity at the Intersection of Groundwater Management and Visualization Research

    Laura Lotteraner, Thilo Hofmann, Torsten Möller
    2023 - IEEE Computer Graphics and Applications, 6: 50-63


    This design study presents an analysis and abstraction of temporal and spatial data, and workflows in the domain of hydrogeology and the design and development of an interactive visualization prototype. Developed in close collaboration with a group of hydrogeological researchers, the interface supports them in data exploration, selection of data for their numerical model calibration, and communication of findings to their industry partners. We highlight both pitfalls and learnings of the iterative design and validation process and explore the role of rapid prototyping. Some of the main lessons were that the ability to see their own data changed the engagement of skeptical users dramatically and that interactive rapid prototyping tools are thus powerful to unlock the advantage of visual analysis for novice users. Further, we observed that the process itself helped the domain scientists understand the potential and challenges of their data more than the final interface prototype.

  • Towards Harmonisation of Testing of Nanomaterials for EU Regulatory Requirements on Chemical Safety – A Proposal for Further Actions

    Eric A. J. Bleeker, Elmer Swart, Hedwig Braakhuis, Maria Luisa Fernandez Cruz, Steffi Friedrichs, Ilse Gosens, Frank Herzberg, Keld Alstrup Jensen, Frank von der Kammer, Jolinde A.B. Kettelarij, José María Navas, Kirsten Rasmussen, Kathrin Schwirn, Maaike Visser
    2023 - Regulatory Toxicology and Pharmacology, 139: 105360


    Over the recent years, EU chemicals legislation, guidance and test guidelines have been developed or adapted for nanomaterials to facilitate safe use of nanomaterials. This paper provides an overview of the information requirements across different EU regulatory areas. For each information requirement, a group of 22 experts identified potential needs for further action to accommodate guidance and test guidelines to nanomaterials. Eleven different needs for action were identified, capturing twenty-two information requirements that are specific to nanomaterials and relevant to multiple regulatory areas. These were further reduced to three overarching issues: 1) resolve issues around nanomaterial dispersion stability and dosing in toxicity testing, in particular for human health endpoints, 2) further develop tests or guidance on degradation and transformation of organic nanomaterials or nanomaterials with organic components, and 3) further develop tests and guidance to measure (a)cellular reactivity of nanomaterials. Efforts towards addressing these issues will result in better fit-for-purpose test methods for (EU) regulatory compliance. Moreover, it secures validity of hazard and risk assessments of nanomaterials. The results of the study accentuate the need for a structural process of identification of information needs and knowledge generation, preferably as part of risk governance and closely connected to technological innovation policy.

  • Training the Next Generation of Plastics Pollution Researchers: Tools, Skills and Career Perspectives in an Interdisciplinary and Transdisciplinary Field

    Denise M. Mitrano, Moritz Bigalke, Andy M. Booth, Camilla Catarci Carteny, Scott Coffin, Matthias Egger, Andreas Gondikas, Thorsten Hüffer, Albert A. Koelmans, Elma Lahive, Karin Mattsson, Stéphanie Reynaud, Stephan Wagner
    2023 - Microplastics and Nanoplastics, 3: 24


    Plastics pollution research attracts scientists from diverse disciplines. Many Early Career Researchers (ECRs) are drawn to this field to investigate and subsequently mitigate the negative impacts of plastics. Solving the multi-faceted plastic problem will always require breakthroughs across all levels of science disciplinarity, which supports interdisciplinary discoveries and underpins transdisciplinary solutions. In this context, ECRs have the opportunity to work across scientific discipline boundaries and connect with different stakeholders, including industry, policymakers and the public. To fully realize their potential, ECRs need to develop strong communication and project management skills to be able to effectively interface with academic peers and non-academic stakeholders. At the end of their formal education, many ECRs will choose to leave academia and pursue a career in private industry, government, research institutes or non-governmental organizations (NGOs). Here we give perspectives on how ECRs can develop the skills to tackle the challenges and opportunities of this transdisciplinary research field and how these skills can be transferred to different working sectors. We also explore how advisors can support an ECRs’ growth through inclusive leadership and coaching. We further consider the roles each party may play in developing ECRs into mature scientists by helping them build a strong foundation, while also critically assessing problems in an interdisciplinary and transdisciplinary context. We hope these concepts can be useful in fostering the development of the next generation of plastics pollution researchers so they can address this global challenge more effectively.

  • Uptake, Metabolism, and Accumulation of Tire Wear Particle- Derived Compounds in Lettuce

    Stephanie Castan, Anya Sherman, Ruoting Peng, Michael Zumstein, Wolfgang Wanek, Thorsten Hüffer, Thilo Hofmann
    2023 - Environ. Sci. Technol., 57: 168-178


    Tire wear particle (TWP)-derived compounds may be of high concern to consumers when released in the root zone of edible plants. We exposed lettuce plants to the TWP-derived compounds diphenylguanidine (DPG), hexamethoxymethylmelamine (HMMM), benzothiazole (BTZ), N-phenyl-N′-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD), and its quinone transformation product (6PPD-q) at concentrations of 1 mg L–1 in hydroponic solutions over 14 days to analyze if they are taken up and metabolized by the plants. Assuming that TWP may be a long-term source of TWP-derived compounds to plants, we further investigated the effect of leaching from TWP on the concentration of leachate compounds in lettuce leaves by adding constantly leaching TWP to the hydroponic solutions. Concentrations in leaves, roots, and nutrient solution were quantified by triple quadrupole mass spectrometry, and metabolites in the leaves were identified by Orbitrap high resolution mass spectrometry. This study demonstrates that TWP-derived compounds are readily taken up by lettuce with measured maximum leaf concentrations between ∼0.75 (6PPD) and 20 μg g–1 (HMMM). Although these compounds were metabolized in the plant, we identified several transformation products, most of which proved to be more stable in the lettuce leaves than the parent compounds. Furthermore, continuous leaching from TWP led to a resupply and replenishment of the metabolized compounds in the lettuce leaves. The stability of metabolized TWP-derived compounds with largely unknown toxicities is particularly concerning and is an important new aspect for the impact assessment of TWP in the environment.

Book chapters and other publications

1 Publication found
  • Microplastics in the Aquatic Environment

    Maren Heß, Carolin Völker, Nicole Brennholt, Pia Maria Herrling, Henner Hollert, Natascha Ivleva, Jutta Kerpen, Christian Laforsch, Martin Löder, Sabrina Schiwy, Markus Schmitz, Stephan Wagner, Thorsten Hüffer
    2023 - 51-86. in Living in the Plastic Age. (Johanna Kramm, Carolin Völker). Campus Verlag GmbH


    Plastikmüll ist überall auf unserem Planeten zu finden. Er hinterlässt einen augenscheinlichen Fußabdruck des menschlichen Konsumverhaltens und der Massenproduktion. Unser ungebremster Plastikkonsum und dessen Auswirkungen prägen die gesellschaftlichen Naturverhältnisse in einer so tiefgreifenden Weise, dass wir vom Plastikzeitalter sprechen. Um Ansätze für einen Umgang mit diesem Problem zu entwickeln, müssen wir das Phänomen umfassend verstehen: Die Autor:innen beleuchten es aus interdisziplinärer Perspektive. Sie zeigen, welche Rolle Kunststoffe in unserer Gesellschaft spielen und welche Auswirkungen sie auf die Umwelt und die menschliche Gesundheit haben