4 Material und Umwelt
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Organisationseinheit der BAM
- 4 Material und Umwelt (1105)
- 4.1 Biologische Materialschädigung und Referenzorganismen (269)
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Paper des Monats
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Die aus der Kirche in Greven entnommenen A. punctatum wiesen größere genetische Unterschiede auf als die aus der isolierten Zucht der BAM. Dies lässt vermuten, dass ein Austausch von zufliegenden oder eingeschleppten Individuen zu einer erhöhten genetischen Variabilität beiträgt.
Die Ergebnisse der Sequenzanalysen vom Standort Greven zeigten, dass vier Variationen vorhanden waren. Die DNA-Barcodes aus der Datenbank NCBI (Frankreich, Finnland und Deutschland) besaßen nur SNPs, die bereits aus den Insekten der Kirche in Greven bekannt waren. Nach aktueller Datenlage für den betrachteten Genabschnitt sind diese Varianten (V2 bis V22) als repräsentativ für den mitteleuropäischen Raum anzunehmen.
Potenzielle weitere Varianten lassen sich nur über eine größere Stichprobenanzahl entdecken/finden. Die Ergebnisse der Käferproben aus der isolierten Zucht der BAM sind deutlich homogener und entsprachen der Variante 1 aus Greven. Die Variante 1 wurde ebenfalls in vier französischen und einer deutschen Probe aus der NCBI-Datenbank nachgewiesen.
Die Ergebnisse deuten auf zwei Hauptvariationen (Vx und V20) hin, wobei die eine (VJ homogener als die andere (V20) zu sein scheint. Da für den Räuber K. caeruleus keine Unterschiede in der COI gefunden wurden, gilt zu prüfen, ob der gewählte Genabschnitt für die Untersuchung repräsentativ ist. Dies ist mit einer höheren Probenzahl zu validieren.
Microbially induced carbonate precipitation (MICP), a widespread phenomenon in nature, is gaining attention as a low-carbon alternative to ordinary Portland cement (OPC) in geotechnical engineering and the construction industry for sustainable development. In the Philippines, however, very few works have been conducted to isolate and identify indigenous, urease-producing (ureolytic) bacteria suitable for MICP. In this study, we isolated seven, ureolytic and potentially useful bacteria for MICP from marine sediments in Iligan City. DNA barcoding using 16s rDNA identified six of them as Pseudomonas stutzeri, Pseudomonas pseudoalcaligenes, Bacillus paralicheniformis, Bacillus altitudinis, Bacillus aryabhattai, and Stutzerimonas stutzeri but the seventh was not identified since it was a bacterial consortium. Bio-cementation assay experiments showed negligible precipitation in the control (without bacteria) at pH 7, 8, and 9. However, precipitates were formed in all seven bacterial isolates, especially between pH 7 and 8 (0.7–4 g). Among the six identified bacterial species, more extensive precipitation (2.3–4 g) and higher final pH were observed in S. stutzeri, and B. aryabhattai, which indicate better urease production and decomposition, higher CO2 generation, and more favorable CaCO3 formation. Characterization of the precipitates by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) and attenuated total reflectance Fourier transform spectroscopy (ATR-FTIR) confirmed the formation of three carbonate minerals: calcite, aragonite, and vaterite. Based on these results, all six identified indigenous, ureolytic bacterial species from Iligan City are suitable for MICP provided that the pH is controlled between 7 and 8. To the best of our knowledge, this is the first report of the urease-producing ability and potential for MICP of P. stutzeri, P. pseudoalcaligenes, S. stutzeri, and B. aryabhattai.
Microbiologically influenced corrosion (MIC) is a crucial issue for industry and infrastructure. Biofilms are known to form on different kinds of surfaces such as metal, concrete, and medical equipment. However, in some cases the effect of microorganisms on the material can be negative for the consistency and integrity of the material. Thus, to overcome the issues raised by MIC on a system, different physical, chemical, and biological strategies have been considered; all having their own advantages, limitations, and sometimes even unwanted disadvantages. Among all the methods, biocide treatments and antifouling coatings are more common for controlling MIC, though they face some challenges. They lack specificity for MIC microorganisms, leading to cross-resistance and requiring higher concentrations. Moreover, they pose environmental risks and harm non-target organisms. Hence, the demand for eco-friendly, long-term solutions is increasing as regulations tighten. Recently, attentions have been directed to the application of nanomaterials to mitigate or control MIC due to their significant antimicrobial efficiency and their potential for lower environmental risk compared to the conventional biocides or coatings. Use of nanomaterials to inhibit MIC is very new and there is a lack of literature review on this topic. To address this issue, we present a review of the nanomaterials examined as a biocide or in a form of a coating on a surface to mitigate MIC. This review will help consolidate the existing knowledge and research on the use of nanomaterials for MIC mitigation. It will further contribute to a better understanding of the potential applications and challenges associated with using nanomaterials for MIC prevention and control.
Here, we report a comparative study of different sum parameter analysis methods for the extraction of per- and polyfluoroalkyl substances (PFAS) from manufactured consumer products, which can be measured by combustion ion chromatography (CIC). Therefore, a hydrolysis-based extraction method was further developed, which accounts for the addition of hydrolyzable covalently bound polyfluoroalkylated side-chain polymers (SFPs) to the extractable organic fluorine portion of the mass balance proposed as "hydrolyzable organically bound fluorine" (HOF). To test this hypothesis, the method was applied to 39 different consumer products containing fluoropolymers or monomeric PFAS taken from four different categories: outdoor textiles, paper packaging, carpeting, and permanent baking sheets. We also evaluated the method's efficiency by extracting four synthesized fluorotelomer polyacrylate reference compounds. The total fluorine (TF) and extractable organically bound fluorine (EOF) values were measured through CIC using established protocols. The TF values ranged from sub-ppb to %-levels, depending on the compound class. All samples showed results for hydrolyzed organofluorine (HOF) between 0.03 and 76.3 μg/g, while most EOF values were lower (<LOD to 58.1 μg/g). Moreover, the methods were contrasted with the "total hydrolyzable precursor" (THP) assay analyzed using gas-chromatography coupled mass spectrometry (GC-MS), which yielded concentrations of 6:2–10:2 fluorotelomer alcohols (<LOD-568 μg/g) for textile and paper samples. Furthermore, targeted analytical investigation of 25 compounds via liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) was conducted and accounted for significantly lower sum amounts (<LOD-0.98 μg PFAS/g). To estimate the fluorine mass balance of all methods, the fluorine levels of target analytical data were calculated and compared to the sum parameter values and evaluated. Finally, the efficiency of the extraction method was approximated by the recovery analysis of four selected SFP model compounds compared to their TF values, yielding 36.7–74.0% after extraction and 3.8–36.3% after processing the extract for the HOF sum parameter.
Investigation on the Durability of a Polypropylene Geotextile under Artificial Aging Scenarios
(2024)
Geosynthetics are widely used in various civil engineering applications, such as geotextiles in coastal protection, and display a sustainable alternative to natural mineral materials. However, the full benefits of using geosynthetics can only be gained with a long service lifetime of the products. With the use of added stabilizers to the polymers, service lifetimes can be achieved in the range of 100 years. Therefore, accelerated aging methods are needed for the assessment of the long-term performance of geotextiles. In the present study, the behavior of geosynthetic materials made of polypropylene was investigated under artificial aging conditions involving elevated temperatures ranging from 30 to 80 °C, increased oxygen pressures ranging from 10 to 50 bar in water-filled autoclaves, and UV irradiation under atmospheric conditions. ATR-IR spectroscopy was employed to detect the increase in the carbonyl index over various aging durations, indicating the oxidative degradation of the geotextile. The most pronounced increase was observed in the case of aging through UV irradiation, followed by thermal aging. Elevated pressure, on the other hand, had a lower impact on oxidation. High-temperature size exclusion chromatography was utilized to follow the reduction in molar mass under different degradation conditions, and the results were consistent with those obtained from ATR-IR spectroscopy. In polyolefins such as polypropylene, Hindered Amine Stabilizers (HAS) are used to suppress oxidation caused by UV radiation. The quantitative analysis of HAS was carried out using a UV/Vis method and HPLC. The degradation of UV stabilizers during the aging of geotextiles is responsible for the oxidation and the reduction in the molar mass of polypropylene. From the results, it can be concluded that applications of PP geotextile without soil or sand cover might cause the risk of the formation of microplastic particles. Material selection, design, and maintenance of the construction must follow best practices, including the system’s removal or replacement at end-of-life. Otherwise, a sustainable use of geotextiles in civil engineering is not possible.
The use of ashes from municipal solid waste incineration as secondary building materials is an important pillar for the circular economy in Germany. However, leaching of potential toxic elements from these materials must be at environmentally acceptable levels. Normally, a three-month ageing period immobilizes most hazardous heavy metals, but antimony (Sb) and vanadium (V) showed previously unusual leaching. In order to clarify the mechanisms, we analyzed the Sb and V species in various bottom and fly ashes from municipal waste incineration by XANES spectroscopy. Antimony oxidizes from Sb(+ III) species used as flame retardants in plastics to Sb(+ V) compounds during waste incineration. However, owing to the similarity of different Sb(+ V) compound in the Sb K- and L-edge XANES spectra, it was not possible to accurately identify an exact Sb(+ V) species. Moreover, V is mainly present as oxidation state + V compound in the analyzed ashes. However, the coarse and magnetic fraction of the bottom ashes contain larger amounts of V(+ III) and V(+ IV) compounds which might enter the waste incineration from vanadium carbide containing steel tools. Thus, Sb and V could be critical potential toxic elements in secondary building materials and long-term monitoring of the release should be taken into account in the future.
Zusammenfassend wurde in dieser Arbeit gezeigt, dass die Setzmaschinentechnik eine geeignete Methode ist, um Brechsande aus gemischten Bauabfällen aufzubereiten. Die Trennung des Materials in zwei Stoffströme unterschiedlicher Dichte hat sich mit einer Absenkung um 56% besonders effizient in der Reduzierung von PAK Belastungen im Feststoff erwiesen. Auch die Sulfatlast im Produktstrom wurde durch den Prozess im Vergleich zum Aufgabegut um 29% gesenkt. Neben der Erhöhung des Median Partikeldurchmessers durch Klassierungseffekte, ist die Herabsetzung verschiedener Eluatparameter ebenfalls positiv zu bewerten. Dies bezieht sich zum einen auf die elektrische Leitfähigkeit, die nach EBV von RC-3 auf RC-1 aufgewertet wurde und zum anderen auf die Chromkonzentration, die von RC-2 auf die Stufe RC-1 angehoben wurde. Die vorliegenden Aufbereitungsergebnisse erlaubten jedoch nicht eine Gesamteinordnung des Materials als Ersatzbaustoff oberhalb der Klasse RC-3. Hierzu ist eine weitere Absenkung der Eluatwerte für Sulfat um 25% von RC-3 (1325 mg L-1) auf RC-2 (< 1000 mg L-1) und des PAK-15 Wertes um 4% von RC-3 (8.3 µg L-1) auf RC-2 (< 8.0 µg L-1) erforderlich. Eine detaillierte Optimierung der Prozessparameter der Setzmaschinentechnik könnten diesen Spielraum ermöglichen.
Einstufung von Aschen und Schlacken aus der Abfallverbrennung im Hinblick auf die weitere Verwertung
(2024)
There are two mirror entries in the European Waste Catalogue for bottom ash and slag from waste incineration: 19 01 11* and 19 01 12. Entry 19 01 11* describes a waste material containing hazardous substances. It was shown that only the hazardous property HP14 (ecotoxic) is of relevance for the classification. If substances with the hazard statement code (HSC) H400, H410, H411, H412 and H413 are present in incineration bottom ash (IBA) above certain level the waste is classified as hazardous, otherwise it is non-hazardous (in this case 19 01 12). It was further shown that only Cu, Zn and Pb compounds have an impact on the classification using a summation rule: 100xΣ c(H410) + 10xΣ c(H411) + Σ c(H412). Limit value is 25 percent. It is obvious that H410 substances have the highest impact. Therefore, the knowledge of the elemental composition of IBA is not sufficient because the content of distinct chemical compounds (with the respective molecular weight) is needed. When the exact speciation is not known a worst-case approach has to be applied. A practical guideline for the estimation of HP14 was developed based on the definition of 4 substance groups: 1. Metals and alloys, 2. Water-soluble substances, 3. Oxides and carbonates and 4. Substances not soluble in weak acids. In substance group 1 only fine Zn powder has the HSC H410. Water-soluble substances are assumed to be H410 substances. Their concentrations are, however, regularly below the cut-off value of 0.1 %. The amount of substance group 3 is estimated by a selective extraction with maleic acid. According to the worst-case approach it is assumed that CuCO3xCu(OH)2 and ZnO represent the respective Cu and Zn species in IBA because these substances have the highest stochiometric factor. Even with this worst-case approach results from operators of IBA treatment plant showed that the limit value of 25 % is not exceeded.
The requirements for utilization of IBA in Germany are defined in the Secondary
Building Materials Decree (Ersatzbaustoffverordnung EBV) which was set into force in August 2023. Leaching methods (batch test or column test) with a liquid-to-solid ratio of 2 l/kg are applied. IBA fulfills the requirements for class HMVA-2. Actually, even a classification of IBA as hazardous (i.e 19 01 11*) would not affect utilization but handling and transport.
Im Rahmen eines vom Umweltbundesamt geförderten Forschungsprojekts wurde untersucht, ob die Abtrennung der Feinfraktion (0-2 mm) eine Verbesserung der umweltrelevanten Eigenschaften bewirkt und somit HMVA-1 erreicht werden kann. In Deutschland wird die Rostasche durch Nassentschlackungssysteme aus dem Feuerraum ausgetragen. Durch den Kontakt mit Wasser setzen direkt hydraulische Reaktionen ein, die eine vollständige Abtrennung der Feinfraktion unmöglich machen. Das wurde bereits in den 1990er Jahren erkannt und führte zur Entwicklung des ABB InRec Verfahrens mit Trockenentaschung als ersten Verfahrensschritt. Auch damals war das Ziel eine möglichst inerte Rostasche für die Verwertung zu erzeugen. In den letzten Jahren wurden in der Schweiz Trockenentaschungssystem installiert, hier vor allem um die Rückgewinnung von elementaren Metallen auch in der Feinfraktion zu verbessern. Welche Potenziale sich dabei erschließen lassen, wurde in einem anderen UBA-Projekt untersucht. Im Rahmen unserer Arbeiten wurde versuchsweise trockene Rostasche an einer Anlage in Süddeutschland genommen und im Labor untersucht. Im Vortrag werden die Ergebnisse zum Auslaugverhalten und zur Gefahreneigenschaft HP14 (Ökotoxizität) vorgestellt.
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).
Understanding Stimulation of Conjugal Gene Transfer by Nonantibiotic Compounds: How Far Are We?
(2024)
A myriad of nonantibiotic compounds is released into the environment, some of which may contribute to the dissemination of antimicrobial resistance by stimulating conjugation. Here, we analyzed a collection of studies to (i) identify patterns of transfer stimulation across groups and concentrations of chemicals, (ii) evaluate the strength of evidence for the proposed mechanisms behind conjugal stimulation, and (iii) examine the plausibility of alternative mechanisms. We show that stimulatory nonantibiotic compounds act at concentrations from 1/1000 to 1/10 of the minimal inhibitory concentration for the donor strain but that stimulation is always modest (less than 8-fold). The main proposed mechanisms for stimulation via the reactive oxygen species/SOS cascade and/or an increase in cell membrane permeability are not unequivocally supported by the literature. However, we identify the reactive oxygen species/SOS cascade as the most likely mechanism. This remains to be confirmed by firm molecular evidence. Such evidence and more standardized and high-throughput conjugation assays are needed to create technologies and solutions to limit the stimulation of conjugal gene transfer and contribute to mitigating global antibiotic resistance.