TY - CONF A1 - Simon, Franz-Georg T1 - Sorptionsverhalten von Antimon an Eisenoxidverbindungen N2 - Aschen und Schlacken aus der thermischen Abfallbehandlung enthalten eine Vielzahl von Schwermetallverbindungen. Für Antimon, Chrom, Kupfer, Molybdän und Vanadium werden in der neuen Ersatzbaustoffverordnung Eluatgrenzwerte für die Verwertung festgelegt. Aschen und Schlacken werden aus der Abfallverbrennungsanlage nass ausgetragen und vor einer Verwertung in der Regel mehrere Wochen gelagert. Dabei finden hydraulische Reaktionen statt und enthaltenes CaO wird zu einem Großteil in Calciumcarbonat umgewandelt. Während wässrige Eluate von frischen Aschen pH-Werte von 12 und höher aufweisen, sind die Eluate nach einigen Wochen weniger stark alkalisch. Die gemessenen Schwermetallkonzentrationen sind daher dann auch deutlich niedriger, mit Ausnahme von Antimon (Sb) und Vanadium (V). Hier steigen die Konzentration mit der Lagerungsdauer. Grund sind sinkende Konzentrationen von Ca-Ionen, die sonst zu einer Ausfällung von Antimonaten und Vanadaten führen. Zu hohe Eluatwerte von Sb und V können durch Sorption an Eisenoxidverbindungen gemindert werden. Als besonders wirkungsvoll hat sich Schwertmannit (Eisen-Oxyhydroxysulfat) erwiesen. Es entsteht durch Oxidation von pyrithaltigem Material durch Mikroorganismen und wird deshalb in Gebieten gefunden, in denen Braunkohle abgebaut wurde, z.B. in der Lausitz. Weitere untersuchte Eisenoxidverbindungen waren Hämatit und Schlämme aus der Abtrennung von Eisen und Mangan in Wasserwerken. T2 - 5. Internationales Bergbausymposium WISSYM 2023 CY - Dresden, Germany DA - 25.09.2023 KW - Rostasche KW - Sorption KW - Ersatzbaustoffe PY - 2023 AN - OPUS4-58702 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koerdt, Andrea T1 - Simulating Microbiologically Influenced Corrosion (MIC) at Seabed Environment in Monopile N2 - Ensuring the safety of offshore wind structures (OWS) is critical to guaranteeing their long-term performance and supporting reliable green energy supply. Microbiologically influenced corrosion (MIC) presents a significant challenge, particularly for monopiles in seabed environments. This study investigates the behavior of microorganisms and their impact on the corrosion process of carbon steel within monopiles. To simulate MIC at the sediment/water interface, an in-house experimental column was developed and inoculated with sediment and water samples from the North Sea. The system was operated under varying flow rates to replicate seabed movement conditions. Multiple molecular microbiological methods, surface analysis techniques, and other approaches were employed to assess the effects of different treatments. This study provides insights into MIC mechanisms in offshore environments and supports the development of strategies to monitor MIC in OWS infrastructure T2 - ISMOS10 CY - Nashville, TN, USA DA - 11.08.2025 KW - MIC KW - Environmental Simulation KW - Field testing KW - Marine Environment PY - 2025 AN - OPUS4-64298 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Altmann, Korinna T1 - Seasonal microplastic concentrations along the rivers Rhine and Danube N2 - Over the last 20 years, many researchers, politicians and citizens have become increasingly aware of the growing plastic problem of our time. A lack of recycling concepts and plastic collection points as well as careless dumping lead to accumulation of plastic products in the environment. Natural weathering can cause these plastics to degrade and fractionate, meaning that microplastics (1 1,000 µm, ISO/TR 21960:2020) and nanoplastics (< 1 µm, ISO/TR 21960:2020) of various synthetic polymer materials can now be detected in all parts of the world. Whether microplastics or nanoplastics pose a toxicological hazard is being investigated in a variety of ways. Valid results are still pending. However, the EU precautionary principle applies to micro- and nanoplastics. Monitoring of microplastics is already required in the revision of the Drinking Water and Wastewater Framework Directive. Reliable monitoring of rivers can be carried out by sampling with sedimentation boxes and microplastic detection by using thermal extraction desorption gas chromatography/mass spectrometry (TED-GC/MS) in routine operation (Figure 1). The river Rhine was sampled for microplastic masses at three different sampling locations over a period of one year and in addition the Danube at randomized sampling locations The TED-GC/MS results showed that various synthetic polymers frequently produced in industry, such as polyethylene, polypropylene or polystyrene as well as the tire compound styrene-butadiene rubber were found. The work not only shows a possible workflow for monitoring concepts, but also provides information on environmentally relevant concentrations of microplastics and tire components in surface waters. This in turn is necessary for ecotoxicological studies. T2 - ESOPS CY - Berlin, Germany DA - 09.09.2024 KW - Microplastics KW - TED-GC/MS KW - Polymer 3R PY - 2024 AN - OPUS4-61016 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Davenport, Rebecca T1 - Regulations versus practice and the Divine Name: Ink analysis in medieval Torah scrolls N2 - The medieval Rabbis had very strict rules for the construction of a Sefer Torah. The Divine Names should be written • by a qualified scribe • who is ritually pure • in the presence of a minyan (10 adult Jewish men) • in an appropriate frame of mind • without being interrupted However, when these scrolls were written it would have been impossible to verify any of this after the fact. While we do not currently have any way to determine how recently the scribes had bathed, or what they might have been thinking as they wrote, we can now know much more about the inscription of the Divine Name than these scribes ever would have guessed. It is sometimes apparent from a visual inspection of the text that the Divine Name has been written in a second stage, from irregular letter kerning or a different ink colour. Using XRF, we have been able to discover more instances of a different ink used for the Name, and have shown that in some cases the secondary ink was also used to correct the main text, suggesting that the later writing was done by a master scribe who also proofread the entire scroll. Using a Brucker M6 Jetstream, it has been possible to produce elemental “heat maps” of whole paragraphs or even large sections of a parchment sheet. Using such large samples of text, we can usefully compare the levels of copper and zinc used to write individual letters or words despite their relatively low concentration, which permits very fine differentiation of the inks used. The techniques presented here would also be highly applicable to assessing ink degradation, as they are able to detect much smaller differences in ink composition than had previously been possible. T2 - The International Iron Gall Ink Meeting 2025 CY - Lisboa, Portugal DA - 07.05.2025 KW - XRF spectroscopy KW - Torah scrolls KW - Jewish studies KW - XRF mapping PY - 2025 AN - OPUS4-65036 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Leube, Peter T1 - Quantification of ultrashort per- and polyfluoroalkyl substances (PFAS) in water samples via headspace gas chromatographymass spectrometry (GC-MS) - a method development N2 - Ultrashort PFAS (≤ 3 carbon atoms) were overlooked for a long time in analytical monitoring. Beside through the use of these substances, they contribute to the PFAS background in the environment through (environmental/ bio-) degradation and incomplete destruction3 of PFAS with longer carbon chains or other fluorinated compounds. As part of the German-Israeli Cooperation in Water Technology Research project „Detection, quantification, and treatment of per- and polyfluoroalkyl substances in groundwater“ (DEFEAT-PFAS), we are developing an as simple as possible direct headspace (HS-)GC-MS method to detect trifluoroacetic acid (TFA) and perfluoropropanioc acid (PFPrA), as well as trifluoroethanol (TFEtOH), pentafluoropropanol(PFPrOH) and hexafluoroiospropanol (HFIP) in water samples. Here we present the results of the PFAS mentioned in spiked ultrapure water solutions. T2 - German Israeli Water Technology Status Seminar CY - Koblenz, Germany DA - 18.06.2024 KW - Ground water KW - Per- and Polyfluoroalkyl substances (PFAS) KW - Gas chromatography - mass spectrometry (GC-MS) PY - 2024 AN - OPUS4-60330 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Leube, Peter T1 - Quantification of ultrashort per- and polyfluoroalkyl substances (PFAS) in water samples via headspace gas chromatography-mass spectrometry (GC-MS) - a method development N2 - Per- and polyfluoroalkyl substances (PFAS) were classified as a group of highly concerning chemicals over the last decades. Because of the high persistence of PFAS, their previous use led to contamination of the environment and human population. Due to ongoing use and incomplete remediation or destruction methods, the PFAS background in the environment is growing continuously. The presence of ultrashort PFAS (with ≤3 carbon atoms) in the environment is often overlooked despite their contributions to PFAS levels. These compounds may directly contaminate the environment and arise from degradation of polyfluorinated compounds as well as incomplete PFAS destruction in certain industrial processes. Nonetheless, few approaches for targeted analysis of ultrashort PFASs have been developed, except for trifluoroacetic acid (TFA). Beside liquid (LC-MS/MS), supercritical fluid (SFC-MS/MS), and ion chromatography (IC-MS)-based systems, gas chromatography coupled with mass spectrometry (GC-MS) is a promising method for detection and quantification of ultrashort PFAS. The goal of this study was to develop a simple headspace GC-MS method for the quantification of ultrashort perfluorocarboxylic acids (PFCAs) and polyfluorinated alcohols (PFOHs) in water samples. In contrast to PFOHs, functionalization of PFCAs was required for quantification. This was done by esterification with methanol at 80 °C, which can be carried out directly in the headspace GC-MS system. Moreover, several parameters were optimized to achieve a low limit of quantification (LOQ) for the analytes used: i) The ratio of the aqueous solution, methanol, and available gas phase within the analysis vessel, ii) the concentration of additional acid in esterification mixtures of PFCAs, iii) shaking frequency and iv) shaking time before analysis. After optimizing the procedure, we were able to quantify ultrashort PFCAs and PFOHs. Thus, our developed headspace GC-MS method has the potential to be used as an alternative target analysis for ultrashort-chain PFCAs and PFOHs in various water samples (groundwater, wastewater). T2 - SETAC Europe 34th Annual Meeting CY - Seville, Spain DA - 05.05.2024 KW - Ultrashort PFAS KW - Headspace GC-MS KW - Perfluorocarboxylic acid (PFCA) KW - Polyfluorinated alcohol (PFOH) PY - 2024 AN - OPUS4-60042 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schuehle, Florian T1 - Quality assured uptake rates for passive sampling of indoor air VOCs N2 - Generation of experimental uptake rates (UR) for > 70 VOCs (7d /100 μg m-3) Application in German Environmental Survey – VOC exposure assessment Assurance of transparency concerning UR generation and uncertainty creates basis for decision making and comparability of measurement results. Exemplarily the uncertainty u(UR) of toluene UR was modelled and determined statistically with own laboratory data (relative standard deviation of actively sampled test gas atmosphere – RSDa and n = 5 exposed passive samplers – RSDp) in line with EN 838 as well as from variation of literature UR – RSD UR,lit. T2 - Airmon 2022, 10th International Symposium on modern principles of air monitoring and biomonitoring CY - Bristol, UK DA - 06.11.2022 KW - IAQ KW - VOC KW - Diffusive sampling KW - Uptake rate PY - 2022 AN - OPUS4-56583 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Misra, Archismita T1 - Polyoxometalate Ionic Liquids as Protective Coatings for Industrial Infrastructure and Cultural Heritage against Microbiologically Influenced Corrosion (MIC) N2 - Corrosion of stone and metal due to acid rain and biodeterioration poses significant challenges for industrial and residential infrastructure, as well as cultural heritage, including statues and historical artefacts. A promising mitigation strategy involves thin, transparent films of polyoxometalate-based ionic liquids (POM-ILs) as chemical shields. Stone samples coated with acid-resistant, biocidal POM-ILs exhibited negligible corrosion when exposed to simulated acid rain, in stark contrast to the severe deterioration of unprotected samples. Additionally, their biocidal properties effectively prevent biofilm formation on coated surfaces. Following studies successfully explored the effectiveness of the coating against lampenflora growing in the Pommery Champagne cellar; and the long-term performance of POM-ILs under outdoor environmental conditions. So, POM-ILs have already demonstrated remarkable anticorrosion and antimicrobial properties against aerobic microorganisms and, being water-insoluble, do not leach into aquatic ecosystem. The current research project repurposes the POM-ILs, extending their application to metals, specifically targeting microbiologically influenced corrosion (MIC) in cultural heritage artefacts made of brass, carbon steel, cast iron, and bronze. This involves optimizing nanocoating adhesion to the metal surface and evaluating its protective efficacy against MIC caused by anaerobic microorganisms such as methanogenic archaea and sulfate reducing bacteria (SRB). This presentation will highlight POM-ILs as sustainable, high-performance nanocoatings for biocorrosion mitigation. It will showcase published success stories, discuss ongoing research and proof-of-concept results, and explore future prospects for these advanced materials in safeguarding metal infrastructure and artefacts across different industrial sectors as well as in the context of cultural heritage conservation. T2 - 10th International symposium on applied microbiology and molecular biology in oil systems (ISMOS10) CY - Nashville, Tennessee, USA DA - 11.08.2025 KW - Polyoxometalates KW - Corrosion KW - Microbiologically Influenced Corrosion KW - Ionic Liquid PY - 2025 AN - OPUS4-64548 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Misra, Archismita T1 - Polyoxometalate Ionic Liquids as Protective Coatings for Industrial Infrastructure and Cultural Heritage against Microbiologically Influenced Corrosion (MIC) N2 - Corrosion of stone and metal due to acid rain and biodeterioration poses significant challenges for industrial and residential infrastructure, as well as cultural heritage, including statues and historical artefacts. A promising mitigation strategy involves thin, transparent films of polyoxometalate-based ionic liquids (POM-ILs) as chemical shields. Stone samples coated with acid-resistant, biocidal POM-ILs exhibited negligible corrosion when exposed to simulated acid rain, in stark contrast to the severe deterioration of unprotected samples. Additionally, their biocidal properties effectively prevent biofilm formation on coated surfaces. Following studies successfully explored the effectiveness of the coating against lampenflora growing in the Pommery Champagne cellar; and the long-term performance of POM-ILs under outdoor environmental conditions. So, POM-ILs have already demonstrated remarkable anticorrosion and antimicrobial properties against aerobic microorganisms and, being water-insoluble, do not leach into aquatic ecosystem. The current research project repurposes the POM-ILs, extending their application to metals, specifically targeting microbiologically influenced corrosion (MIC) in cultural heritage artefacts made of brass, carbon steel, cast iron, and bronze. This involves optimizing nanocoating adhesion to the metal surface and evaluating its protective efficacy against MIC caused by anaerobic microorganisms such as methanogenic archaea and sulfate reducing bacteria (SRB). This presentation will highlight POM-ILs as sustainable, high-performance nanocoatings for biocorrosion mitigation. It will showcase published success stories, discuss ongoing research and proof-of-concept results, and explore future prospects for these advanced materials in safeguarding metal infrastructure and artefacts across different industrial sectors as well as in the context of cultural heritage conservation. T2 - Euro-MIC COST Action - Closing Workshop Conference CY - Horsens, Denmark DA - 17.09.2025 KW - Polyoxometalates KW - Corrosion KW - Microbiologically Influenced Corrosion KW - Ionic Liquid PY - 2025 AN - OPUS4-64549 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Musyanovych, A. A1 - Grimmer, Christoph A1 - Sadak, A. E. A1 - Heßling, L. A1 - Bilsel, M. A1 - Horn, Wolfgang A1 - Richter, Matthias T1 - Polymeric Capsules with VOCs for Controlled Emission N2 - Micro-(nano-)encapsulation technology involves building of a barrier between the core and the environment and offers a number of benefits to preserve the functional and physicochemical properties of core material. Tremendous progress has been made in synthesizing well-defined capsules to achieve desired properties such as particle size, chemical composition, and controlled release of the payload. Encapsulation of volatile organic compounds (VOCs) that could evaporate with a defined rate is of immense interest for application in emission reference materials (ERM). These are urgently needed for quality assurance and quality control purposes (QA/QC) required by test standards for the determination of chemical emissions of construction and other materials for interior use. As such ERMs are hardly available on the market, the EU-funded EMPIR project MetrIAQ [1] was started to fill this gap by developing a material with temporally constant emission of VOCs typically found in indoor air. Different capsules in a size range between 5 and 50 μm were synthesized through an interfacial polyaddition/polycondensation reaction in direct (water-in-oil) system. As VOC several types of hydrophobic liquid materials were used. After synthesis, the morphology and physicochemical properties of capsules were characterized by electron microscopy, FTIR and DSC/TGA. An encapsulation efficiency up to 90% could be reached. The emission kinetic of volatile agents was studied in emission test chambers at 23 °C and 50% RH for 14 days. First results indicate that variation of the cross-linking grade of the shell material is one important parameter to adjust the desired emission rate. The overall aim is to achieve a consistent emission profile that decreases by less than 10 % over a target period of at least 14 days. T2 - 36th European Colloid & Interface Society Conference CY - Chania, Crete, Greece DA - 04.09.2022 KW - Capsules KW - Volatile organic compound KW - Polymer KW - Material emissions KW - Reference materials PY - 2022 AN - OPUS4-56039 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Musyanovych, A. T1 - Polymeric Capsules with VOCs for Controlled Emission N2 - Micro-(nano-)encapsulation technology involves building a barrier between the core and the environment and offers several benefits to preserve the functional and physicochemical properties of core material. Tremendous progress has been made in synthesizing well-defined capsules to achieve desired properties such as particle size, chemical composition, and controlled release of loaded compounds. Encapsulation of volatile organic compounds (VOCs) that could evaporate with a defined rate is of immense interest for application in emission reference materials (ERM). These are urgently needed for quality assurance and quality control purposes (QA/QC) required by test standards for the determination of chemical emissions of construction and other materials for interior use. As such ERMs are hardly available on the market, the EU-funded EMPIR project MetrIAQ was started to fill this gap by developing a material with temporally constant emission of VOCs typically found in indoor air. T2 - 36th European Colloid & Interface Society Conference CY - Chania, Crete, Greece DA - 04.09.2022 KW - Capsules KW - Volatile organic compounds KW - Material emissions KW - QA/QC KW - Reference materials PY - 2022 AN - OPUS4-55917 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Keshmiri, Hamid T1 - Plasmon-enhanced diffractive supercells N2 - Multiple diffractive surface modulations can concurrently couple the light to several electromagnetic surface waves. We present a multi-resonant plasmonic supercell structure with a broad range of applicability in harvesting the light over an extensive wavelength range and angles of incidence. T2 - Molecular Plasmonics 2023 CY - Jena, Germany DA - 11.05.2023 KW - Optics PY - 2023 AN - OPUS4-59248 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Taghavi Kalajahi, Sara T1 - Pilot Study of a Laboratory- Based Microbiologically Influenced Corrosion (MIC) Test Using Microbiological Consortia Sampled from the Field N2 - Experts widely agree that the verification of microbiologically influenced corrosion (MIC) require the use of multiple lines of evidence (MLOE), including metallurgical, microbiological, operational/historical and environmental/chemical aspects. Existing standards related to MIC, such as NACE TM0106, TMO212 and TM0194, primarily aim to offer guidance on gathering such evidence. Working Group 5 of Euro-MIC COST action 20130 (Achieving standardization) proposed a laboratory-based approach that directly confirms the capability of the sampled consortium of microorganisms, obtained from the specific field location under investigation, to increase and/or alter the corrosion processes. It is necessary to verify this laboratory approach by conducting it in different laboratories, performed by different scientist. In the current study, the experiments based on the laboratory protocol of WG5 were conducted at Endures’s laboratory using environmental samples (sediment and seawater) from the North Sea. Metal coupons (carbon steel C1010) were exposed to sediment and seawater samples with varying microbial inoculums and controls over 150 days. Microbial identification, corrosion product analysis, and surface morphology assessments were conducted using molecular and microscopy techniques. The results indicate distinct microbial influences, particularly in treatments containing yeast, which fostered heightened anaerobic activity, notably by sulfate-reducing bacteria (SRB). Weight loss measurements and surface analysis revealed elevated corrosion rates and susceptibility to pitting corrosion in microbial inoculum treatments, with yeast presence exacerbating corrosion processes. Elemental analysis confirmed the presence of iron sulfide in corrosion byproducts, affirming SRB activity. The findings emphasize the importance of employing a MLOE approach and investigating pitting corrosion to better understand the impact of microorganisms on metal corrosion in the marine environments. This study contributes to advancing knowledge in the field and developing standardization: the lab-to-field transition for MIC testing. T2 - MIC-STANDS CY - Lisbon, Portugal DA - 24.07.2024 KW - Microbiologically influenced corrosion (MIC), Multiple lines of evidence (MLOE) KW - Marine Corrosion KW - Achieving standardization PY - 2024 AN - OPUS4-61979 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Physiological and evolutionary consequences of exposing Pseudomonas aeruginosa to biocide-antibiotic combinations N2 - Antimicrobials can exert specific physiological effects when used in combination that are different from those when applied alone. These effects include physiological effects (i.e. synergy, antagonism and suppression) as well as evolutionary effects on the selection of resistant strains (i.e. cross-resistance and collateral sensitivity). While combination effects have been extensively mapped for antibiotic-antibiotic combinations, the combination effects of antibiotics with antimicrobials used as biocides or antiseptics have not been systematically investigated. Here, we investigated the physiological and evolutionary consequences of combinations of antibiotics (meropenem, gentamicin and ciprofloxacin) and substances used as biocides or antiseptics (octenidine, benzalkonium chloride, cetrimonium bromide, chlorhexidine, povidone-iodine, silver) on growth and selection of Pseudomonas aeruginosa. We find prevalent physiological combination effects with synergy occurring 6 times and antagonism occurring 10 times. The effects are specific to the antibiotic-biocide combination with meropenem showing a tendency for antagonism with biocides (6 of 7), while gentamicin has a tendency for synergy (5 of 7). A particular strong antagonism is apparent for the meropenem-chlorhexidine combination, for which we conducted an in-depth study on the underlying molecular mechanism using RNASeq. Moreover, we find widespread effects of the biocide-antibiotic combinations on selection of P. aeruginosa strains resistant to the antibiotics, including cross-resistance and collateral sensitivity. In conclusion, antibiotics and biocides or antiseptics exert physiological and evolutionary combination effects on the pathogen P. aeruginosa. These effects have consequences for the efficacy of both types of substances and for the selection of antimicrobial resistant strains in clinical applications with combined exposure (e.g. wound care, coated biomaterials). T2 - ASM-FEMS World Microbe Forum CY - Online meeting DA - 20.06.2021 KW - Antimicrobial resistance KW - Antagonism KW - Biofilms PY - 2021 AN - OPUS4-53165 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Phenotypic and evolutionary responses of bacteria to disinfection N2 - Disinfectants are important to prevent the transmission of pathogens, especially in the face of the current antibiotic resistance crisis. The crisis is further exacerbated by phenotypically tolerant persister subpopulations that can survive transient antibiotic treatment and facilitate resistance evolution. Despite the transient nature of disinfectant application, persistence to disinfectants and its role for the evolution of tolerance and cross-resistance to antibiotics has not been studied. Our work shows that E. coli displays persistence against several widely used disinfectants, including benzalkonium chloride (BAC), didecyldimethylammoniumchlorid (DDAC) and isopropanol. The molecular mechanism of BAC persistence is triggered in stationary phase and affected by several antibiotic persister genes (hipA, tisB, tolC, relA, spoT). Experimental evolution and population dynamic modeling show that repeated failure of disinfection due to persisters rapidly selects for BAC tolerance underpinned by reduced cell surface charge due to mutations in genes related to lipid A acylation (lpxML). Furthermore, evolved BAC tolerance affects the susceptibility to antibiotics, leading to positive selection of disinfectant tolerant strains at environmentally relevant antibiotic concentrations and variations in evolvability of antibiotic resistance due to epistatic effects. These results highlight the need for faithful application of disinfectants to steward their efficacy and the efficacy of antibiotics. A better understanding of the bacterial response to disinfectants is crucial to understand and avert the ongoing antimicrobial resistance crisis. T2 - Gordon Research Conference - Molecular mechanisms of evolution CY - Easton, MA, United States DA - 25.06.2023 KW - Antimicrobial resistance KW - Bacteria KW - Disinfection KW - Biocides PY - 2023 AN - OPUS4-57861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nordholt, Niclas A1 - Schreiber, Frank T1 - Persistence against benzalkonium chloride promotes rapid evolution of tolerance under periodic disinfection N2 - Biocides used as disinfectants are important to prevent the transmission of pathogens, especially during the current antibiotic resistance crisis. This crisis is exacerbated by phenotypically tolerant persister subpopulations which can survive transient antibiotic treatment and facilitate resistance evolution. Despite the transient nature of disinfection, knowledge concerning persistence to disinfectants and its link to resistance evolution is currently lacking. Here, we show that E. coli displays persistence against a widely used disinfectant benzalkonium chloride (BAC). Periodic, persister-mediated failure of disinfection rapidly selects for BAC tolerance. BAC tolerance is associated with reduced cell surface charge and mutations in the novel tolerance locus lpxM. Moreover, the fitness cost incurred by BAC tolerance turned into a fitness benefit in the presence of antibiotics, suggesting a selective advantage of BAC-tolerant mutants in antibiotic environments. Our findings provide a mechanistic underpinning for the faithful application of disinfectants to prevent multi-drug-resistance evolution and to steward the efficacy of biocides and antibiotics. T2 - World Microbe Forum (ASM, FEMS) CY - Online meeting DA - 20.06.2021 KW - Persistence KW - Biocides KW - Evolution KW - Cross-resistance KW - Biocide tolerance PY - 2021 AN - OPUS4-53167 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nordholt, Niclas T1 - Persistence against benzalkonium chloride promotes rapid evolution of tolerance under periodic disinfection N2 - The exposure to antimicrobial substances drives the evolution of antimicrobial resistance (AMR). Biocides are antimicrobials used as disinfectants, antiseptics and preservatives. They find application on a large scale in the industrial and medical sector, but also in private households. In terms of mass, the worldwide use of biocides exceeds that of antibiotics. Thus, despite their important role in preventing the spread of pathogens, due to their ubiquity, biocides are suspected to be drivers of the antimicrobial resistance crisis. In our work we try to understand how biocides contribute to the emergence of AMR, what the underlying adaptation principles and mechanisms are and how they compare to those found for antibiotics. Here, I present results which demonstrate that phenotypic heterogeneity in E. coli, namely the formation of tolerant persister cells, can enable the survival of disinfection and consequentially facilitate the evolution of AMR. Using experimental evolution that selects for tolerance, we find that mutations in lipid A biosynthesis arise following periodic treatment with benzalkonium chloride (BAC), a widely used disinfectant. BAC tolerance is associated with additional, diverse mutations as well as changes in the susceptibility to antibiotics from different classes and changes in motility and biofilm formation, suggesting extensive regulatory re-wiring in the evolved clones. Remarkably, we find that fitness costs (growth rate reduction) incurred by BAC tolerance are alleviated in the presence of antibiotics. These findings demonstrate the complexity underlying the adaptation to antimicrobials and highlight the links between persistence to disinfectants and resistance evolution to antimicrobials. T2 - Bacterial Networks (BacNet22) CY - Sant Feliu de Guixols, Spanien DA - 04.09.2022 KW - Persistence KW - Biocides KW - evolution KW - disinfection KW - biocide tolerance PY - 2022 AN - OPUS4-55713 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank A1 - Nordholt, Niclas T1 - Persistence against benzalkonium chloride promotes rapid evolution of tolerance under periodic disinfection N2 - Biocides used as disinfectants are important to prevent the transmission of pathogens, especially during the current antibiotic resistance crisis. This crisis is exacerbated by phenotypically tolerant persister subpopulations which can survive transient antibiotic treatment and facilitate resistance evolution. Despite the transient nature of disinfection, knowledge concerning persistence to disinfectants and its link to resistance evolution is currently lacking. Here, we show that E. coli displays persistence against a widely used disinfectant benzalkonium chloride (BAC). Periodic, persister-mediated failure of disinfection rapidly selects for BAC tolerance. BAC tolerance is associated with reduced cell surface charge and mutations in the novel tolerance locus lpxM. Moreover, the fitness cost incurred by BAC tolerance turned into a fitness benefit in the presence of antibiotics, suggesting a selective advantage of BAC-tolerant mutants in antibiotic environments. Our findings provide a mechanistic underpinning for the faithful application of disinfectants to prevent multi-drug-resistance evolution and to steward the efficacy of biocides and antibiotics. T2 - New Approaches and Concepts in Microbiology CY - Online meeting DA - 07.07.2021 KW - Persistence KW - Biocides KW - Evolution KW - Cross-resistance KW - Biocide tolerance PY - 2021 AN - OPUS4-53168 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Vogel, Christian T1 - Per- and polyfluoroalkyl substances (PFAS) in ski waxes and snow from cross-country skiing in Germany - Comparative study of target analysis and sum parameters N2 - Per- and polyfluoroalkyl substances (PFAS) can enter the environment in different ways. Possible sources are PFAS containing consumer products. One common product that makes use of the material properties of PFAS is ski wax. Here, the PFAS ensure less frictional resistance, thus allows for increased speed. However, people who wax their ski with these waxes could absorb PFAS in their body, which can lead to health problems in the long term. Moreover, PFAS applied in ski wax abrade onto snow during use, which contaminates the environment. In our study, we analyzed various currently available ski waxes (2020s) and ski waxes from the 1980s with PFAS target analysis and with the sum parameters extractable organically bound fluorine (EOF), hydrolysable organically bound fluorine (HOF) and total fluorine (TF). Moreover, snow samples from the long-distance cross-country ski trail “Kammloipe” in the Ore mountains in Germany where sampled and analyzed with PFAS target analysis and the adsorbable organically bound fluorine (AOF) sum parameter to document the entry of PFAS from ski waxes into the environment. In opposite to the ski waxes from the 1980s much more ski waxes from the 2020s contain high (total) fluorine values. The highly fluorinated ski waxes contain up to approx. 6% of fluorine. The EOF and HOF sum parameters of the ski waxes are strongly decreased in comparison to the TF values (max. approx. 1000 mg/kg = 0.1%). But even the PFAS-free labeled ski waxes have EOF/HOF values in the low mg/kg range. In the snow samples from different spots of the ski trail, both the AOF sum parameter and the PFAS target analysis identified PFAS. Moreover, on a PFAS hotspot also soil samples were analyzed, which indicate that PFAS from the ski waxes adsorb after snow melting into the soil. Thus, our results show that the use of ski waxes is a possible contribution to the environmental contamination of PFAS, which is hopefully drastically reduced with the ban on fluorinated waxes by the International Ski and Snowboard Federation (FIS). T2 - SETAC Europe CY - Vienna, Austria DA - 11.05.2025 KW - Per- and polyfluoroalkyl substances (PFAS) KW - Contaminated Soil KW - Ski wax PY - 2025 AN - OPUS4-63096 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gehrenkemper, Lennart T1 - Organically bound fluorine in river water - A methode comparison of CIC and HR-CS-GFMAS N2 - Abstract: Since it is unknown for many applications, which PFASs are used and how they enter the environment, target analysis-based methods reach their limits. The two most frequently used sum parameters are the adsorbable organically bound fluorine (AOF) and the extractable organically bound fluorine (EOF). Both can be quantified using either combustion ion chromatography (CIC) or high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS). Here we provide an insight on the advantageous and disadvantageous of both sum parameters and both detection methods. Our study is based on the analysis of surface water samples. Next to total fluorine (TF) analysis, AOF and EOF were determined as well as CIC and HR-CS-GFMAS are compared and results are comparatively discussed. Fluorine mass balancing revealed that, the AOF/TF proportion was higher than the EOF/TF proportion. The AOF made up 0.14–0.81% of TF and the EOF 0.04–0.28% of TF. Although, organically bound fluorine represents only a small portion of TF, PFASs are of worldwide concern, because of their extreme persistence and their bioaccumulation potential. The EOF-HR-CS-GFMAS method turned out to be more precise and sensitive than the AOF-CIC method and is a promising tool for future monitoring studies/routine analysis of PFASs in the environment. T2 - SALSA Make and Measure 2020: Advanced Characterization of Materials CY - Online meeting DA - 15.10.2020 KW - High resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) KW - Combustion ion chromatography (CIC) KW - Per- and polyfluorinated alkyl substances (PFASs) KW - Adsorbable organically bound fluorine (AOF) KW - Extractable organically bound fluorine (EOF) KW - Surfacewaters PY - 2020 AN - OPUS4-52451 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -