4 Material und Umwelt
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There is a need for an assessment of the emission properties of volatile organic compounds (VOCs) from consumer products. A method comparison was carried out to evaluate adapted and cost-effective procedures for such items. Smaller and automated emission chambers de-picted similar kinetics compared to a 203 L standard chamber. Toy samples made of PVC (Polyvinyl chloride) emitted more VOCs compared to other tested polymeric products. The emissions from 2 selected samples were studied to allow an evaluation of the resulting room concentration and external exposure of a child. Obtained concentrations were not of concern.
Two new approaches towards an emission reference material for use in quality assurance measures for materials emissions testing were developed and intensively tested. The overall goal was to obtain solid materials with homogenous and reproducible (S)VOC release. Since the application in inter-laboratory comparisons is aimed at, it should furthermore be long-term stable to ensure safe shipment to the customer without sustaining compound losses. In the first approach, thermoplastic polyurethane (TPU) was impregnated with the VOC texanol under high-pressure with liquid CO2 as solvent. In the second, styrene (VOC) and the SVOC 2,6-diisopropylnaphthalene (DIPN) were spiked into vacuum grease (VG) and a mixture of paraf-fin/squalane (P/S). For the prediction of the emission rates a finite element model (FEM) was developed for the VG and P/S type materials. All requirements for reference materials were fulfilled, whereas the TPU samples need to be aged for about 10 days until repeatable and re-producible emission rates were obtained.
The possible impact of ultrafine particles from laser printers on human health is controversially discussed although there are persons reporting substantial symptoms in relation to these emissions. A randomized, single-blinded, cross-over experimental design with two exposure conditions (high-level and low-level exposure) was conducted with 23 healthy subjects, 14 subjects with mild asthma, and 15 persons reporting symptoms associated with laser printer emissions. To separate physiological and psychological effects, a secondary physiologically based categorization of susceptibility to particle effects was used. In line with results from physiological and biochemical assessments, we found no coherent, differential, or clinically relevant effects of different exposure conditions on subjective complaints and cognitive performance in terms of attention, short-term memory, and psychomotor performance. However, results regarding the psychological characteristics of participants and their situational perception confirm differences between the participants groups: Subjects reporting symptoms associated with laser printer emissions showed a higher psychological susceptibility for adverse reactions in line with previous results on persons with multiple chemical sensitivity or idiopathic environmental intolerance. In conclusion, acute psychological and cognitive effects of laser printer emissions were small and could be attributed only to different participant groups but not to differences in exposure conditions in terms of particle number concentrations.
Comparison of Formaldehyde Concentrations in Emission Test Chambers Using EN 717-1 and EN 16516
(2018)
For more than 25 years EN 717-1 (Wood-based panels - Determination of formaldehyde re-lease - Part 1: Formaldehyde emission by the chamber method) is the standard for formalde-hyde emission testing of wooden boards. In 2017 EN 16516 (Construction products - Assess-ment of release of dangerous substances - Determination of emissions into indoor air) was published as a new harmonised standard for the emission testing of construction products. Because test chamber conditions are different, both standards give different concentrations for formaldehyde. To determine a conversion factor four test series were set up with different wooden boards. For a loading of 1 m²/m³ the conversion factor is 1.6. This means that the formaldehyde concentration measured under the conditions of EN 16516 is a factor of 1.6 higher compared to EN 717-1.
The development of a test to evaluate the degradation of semi-volatile fuels as diesel by microorganisms is presented. This method is based on the principles described in the CEC-L-103 Standard procedure that is exclusively meant for testing the biodegradability of non-volatile lubricants. Therefore, significant modifications involve aseptic conditions for testing specific microorganisms and conducting the test in closed vessels avoiding evaporation losses, while fuel quantification using gas chromatography-flame ionization detection (GC-FID) is retained. It is suggested that the modified procedure should enable routine application for semi-volatile hydrocarbon-based fuels. GC-FID provides additionally valuable information on the alteration of fuel component patterns during biodegradation. The procedure was successfully tested using two bacteria (Pseudomonas aeruginosa and Sphingomonas sp.) and two yeasts (Moesziomyces sp. and Candida sp.) isolated from real diesel contamination cases. All tested microorganisms caused a significant degradation of diesel fuel achieving hydrocarbon degradation percentages ranging from 23% to 35%. Specific aspects on the test modification and prospects for further modification regarding targeted investigations in the field of fuel contamination by microorganisms are briefly discussed.
Wood treated with nano metal fluorides is found to resist fungal decay. Sol−gel synthesis was used to synthesize MgF2 and CaF2 nanoparticles. Electron microscopy images confirmed the localization of MgF2 and CaF2 nanoparticles in wood. Efficacy of nano metal fluoride-treated wood was tested against brown-rot fungi Coniophora puteana and Rhodonia placenta. Untreated wood specimens had higher
mass losses (∼30%) compared to treated specimens, which had average mass loss of 2% against C. puteana and 14% against R. placenta, respectively. Nano metal fluorides provide a viable alternative to current wood preservatives.
Virologists. You might know a couple of them, but unless you are a virologist yourself, the probability that you have collaborated with one in the past is low. The community is relatively small, but they pack a heavy punch and are expected to play a leading role in the research into pathogens that lies ahead. You may ask why we think virologists are our future. Suffice it to say that it is not just because they have invented technologies that belong to the space age, including use of viruses as vehicles to shuttle genes into cells[1], organic nanoparticles with specific tools attached to their surfaces to get inside target cells[2], and using genetically modified viruses as therapies to fight against cancer[3]. Did you know that virologists currently only know of about 3,200 viral species but that more than 320,000 mammal-associated viruses[4] are thought to await discovery? Just think about the viruses hidden in the Arctic ice[5] or in the insects and other animals from once cut-off regions in the world, which now face ever-increasing human exposure[6]. But a heroic (as well as an apocalyptic) role for virologists may also be on the horizon, as the adoption of phage therapy may, in the future, be used to control harmful bacteria when antibiotics fail
Soiling of photovoltaic (PV) systems compromises their performance causing a significant power loss and demanding periodical cleaning actions. This phenomenon raises great concerns in the solar energy field, thus leading to notable research efforts over the last decades. Soiling is caused by a dual action of dust deposition and biofouling. However, surprisingly, the microbiological contribution to PV soiling is often overlooked or underestimated. In this study, a variety of qPCR-based methods have been developed to quantify the microbial load of fungi, bacteria and phototrophs on PV panels. These protocols were evaluated by comparison with culturedependent methods, and were implemented with real solar plants for two years. The results show that the developed molecular methods are highly sensitive and reliable to monitor the microbial component of the soiling. Fungal biomass was clearly dominant in all analysed PV modules, while bacteria and phototrophs showed much lower abundance. Light microscopy and qPCR results revealed that melanised microcolonial fungi and phototrophs are the main biofilm-forming microorganisms on the studied solar panels. In particular, the fungal qPCR protocol is proposed as a useful tool for monitoring of PV soiling, and investigating the microbial contribution to specific soiling cases.
Recent DNA-based studies have shown that the built environment is surprisingly rich in fungi. These indoor fungi – whether transient visitors or more persistent residents – may hold clues to the rising levels of human allergies and other medical and building-related health problems observed globally. The taxo¬nomic identity of these fungi is crucial in such pursuits. Molecular identification of the built mycobiome is no trivial undertaking, however, given the large number of unidentified, misidentified, and technically compromised fungal sequences in public sequence databases. In addition, the sequence metadata required to make informed taxonomic decisions – such as country and host/substrate of collection – are often lacking even from reference and ex-type sequences. Here we report on a taxonomic annotation workshop (April 10–11, 2017) organized at the James Hutton Institute/University of Aberdeen (UK) to facilitate reproducible studies of the built mycobiome. The 32 participants went through public fungal ITS bar¬code sequences related to the built mycobiome for taxonomic and nomenclatural correctness, technical quality, and metadata availability. A total of 19,508 changes – including 4,783 name changes, 14,121 metadata annotations, and the removal of 99 technically compromised sequences – were implemented in the UNITE database for molecular identification of fungi (https://unite.ut.ee/) and shared with a range of other databases and downstream resources. Among the genera that saw the largest number of changes were Penicillium, Talaromyces, Cladosporium, Acremonium, and Alternaria, all of them of significant importance in both culture-based and culture-independent surveys of the built environment.
Tools for the characterization of secondary raw materials - status of leaching test application
(2018)
Leaching tests are used as tools for the assessment of environmental compatibility of granular waste materials with potential for reuse. The presentation gives an overview on available leaching tests, their field of application and relation to legislation. Furthermore robustness testing to elaborate optimized test conditions as well as performance characteristics from validation studies by BAM are addressed.
Tools for the characterization of secondary raw materials - status of leaching test application
(2018)
Leaching tests are used as tools for the assessment of environmental compatibility of granular waste materials with potential for reuse. The presentation gives an overview on available leaching tests, their field of application and relation to legislation. Furthermore robustness testing to elaborate optimized test conditions as well as performance characteristics from validation studies by BAM are addressed.
Development of a methodical approach for in-situ analysis of modern reverse paintings on glass
(2018)
The technique of painting on the reverse side of glass was rediscovered by artists in the early 20th century and gained great popularity, especially in Germany. In contrast to other paint techniques (e.g. panel and mural painting), the paint layers are applied in reverse succession starting with the foremost paint layer and ending with the primer (backmost layer). The paintings are viewed in reflected light, thus revealing an impressive gloss, luminosity and depth of colour.
Scientific investigation of the material provides important information for appropriate conservation concepts. Transport of the precious and fragile objects to the lab is often not feasible. Therefore, in-situ, non-invasive analysis is necessary to analyse colorants and binders. However, some analytical problems need to be considered: due to the reverse paint stratigraphy in reverse paintings on glass, the measured layer is always the backmost one. The analytical possibilities are extremely reduced, when the back is covered by a metal foil (or by paper, carton etc.). However, measurements through the glass (using Raman and VIS) can still yield information on the colourants of the front layer.
When the paint layer is accessible, we start our procedure using X-ray fluorescence (Tracer III-SD, Bruker AXS Microanalysis GmbH, 40 kV, 15 μA) and VIS reflectance spectroscopy (SPM 100, Gretag-Imaging AG). Both techniques provide first information on the inorganic colourants. Raman measurements (i-Raman®Plus, Bwtek inc., 785 nm, 50× objective, resolution 4 cm-1) are then carried out to clarify uncertain XRF measurements and to identify synthetic organic pigments (SOP). Diffuse Reflection-Infrared-Fourier-Transform Spectroscopy (DRIFTS; ExoScan, Agilent GmbH, 4000–650 cm-1, 500 scans, spectral resolution 4 cm-1) is used for the classification of the binders. Moreover, it may help to identify SOP, when fluorescence dominates the Raman signal. This analytical sequence yields the best results, when time is the limiting factor.
We present two in-situ studies of the paintings “Kreuzabnahme” (1914-15) by Carlo Mense and “Stadt am Morgen” (1921) by Walter Dexel. The painting “Kreuzabnahme” is an outstanding piece in Mense’s ɶuvre, because the glass plate was painted on both sides (Fig. 1). The results of the back-side show mainly inorganic pigments: basic lead white, talc, red and brown ochre, cinnabar, chrome yellow, viridian, ultramarine blue, Prussian blue and bone black. The classification of binding media using DRIFTS yields positive results for drying oil. Acrylic resin could be identified in two areas, resulting from a previous restauration treatment. For the front side painting, Mense used basic lead white, cinnabar, chrome yellow and umbra as pigments and oil as binder.
Measurements of the abstract painting “Stadt am Morgen” by Walter Dexel show zinc white, basic lead white, chalk, cinnabar, red lead, strontium yellow, cadmium yellow, cobalt blue, Prussian blue, ultramarine blue, brown ochre and bone black as pigments. Moreover, synthetic alizarin (PR83) was identified as dark red colorant. The results of DRIFTS classify oil as binding media.
We conclude that, the use of complementary spectroscopic methods yields the best results for in-situ analysis of reverse paintings on glass.
Zearalenone (ZEN) and its sulfate and glucoside conjugates have been detected in (a broad variety of) food and feed commodities1. Both conjugated derivatives are formed as part of fungal or plant secondary metabolism and thus, belong to the group of modified mycotoxins2. After consumption of contaminated foodstuff, the conjugates can be hydrolyzed by human intestinal microbiota leading to liberation of ZEN that implies an underestimation of the true ZEN exposure. In order to include ZEN conjugates in routine analysis, as well as for toxicological investigation reliable standards are needed.
The objective of the present study was to develop a simple and economic method for biosynthesis of ZEN conjugates. Preceding experiments on the biotransformation of ZEN by Rhizopus and Aspergillus species showed a mixed metabolite formation3. Therefore, these known ZEN conjugating fungal strains were screened for their potential to selectively synthesize the ZEN derivatives ZEN-14-sulfate (Z14S), ZEN-14-glucoside (Z14G) and ZEN-16-glucoside (Z16G). The screening was conducted by adding ZEN to liquid fungal cultures. Cultivation conditions and ZEN incubation time were varied. All media samples were analyzed for metabolite formation by HPLC-MS/MS. Z14S was exclusively formed by A. oryzae. Under optimized conditions a specific biosynthesis of Z14G by R. oryzae and Z16G by R. oligosporus was achieved. After liquid-liquid-extraction and preparative chromatographic cleanup 1H-NMR purities of ≥ 73% for Z14S, ≥ 82% for Z14G and ≥ 50% for Z16G were obtained. In addition, a consecutive biosynthesis was developed by first using Fusarium graminearum for ZEN biosynthesis on rice based liquid medium. After inactivation of Fusarium the subsequent conjugation reaction was conducted utilizing Aspergillus and Rhizopus species under the various optimized conditions.
In this study an easy and cost-efficient biosynthesis for Z14S, Z14G and Z16G was developed. The developed biosynthesis could be also used for other metabolites like ZEL conjugates. Our results of the in vitro screening indicate also the formation of a ZEL-glucoside and α ZEL-sulfate as major metabolites by R. oryzae. In sum, under optimized cultivation conditions fungi can be easily utilized for a targeted and stereospecific synthesis of ZEN conjugates.
Infections with multi-resistant Gram negative pathogens are a major threat to our health system. In order to serve the needs in antibiotics development we selected untapped bioresources and implemented high throughput approaches suitable for the discovery of strains producing antibiotics with anti-Gram negative activity.
Our approaches rely on the hypothesis that Termite associated bacteria are likely to produce potent antibiotics to defend their hosts against entomopathogenic microorganisms. Termite nests and guts harbor suitable, highly diverse microbiomes in which bacterial taxa are present known to potentially produce natural compounds. In
a first step the diversity of Coptotermes species nest microbiomes was assessed carefully by using 16S rDNA amplicon sequencing on the Illumina MiSeq platform and nest material was selected to retrieve viable cells by using Nycodenz density gradient centrifugation. In order to analyze the diversity of the culturable termite nest microbiome, bacterial cells were either distributed in 384-well plates
(approach 1) or encapsulated in small spheric agarose beads by an high throughput microfluidics technique (approach 2). Cultures obtained from approach 1 were scaled-up in 96-well Duetz-systems for characterization of diversity and for rapid supernatant screening using the bioluminescence-labeled E. coli pFU166. The generated
droplets of approach 2 simultaneously received a small population of GFP-tagged Gram negative screening cells and were sorted for low fluorescence using FACS. After elimination of redundancy we performed a fast scale-up of active strains.
Implementation of this pipeline allows us to prioritize antibiotics producing strains in a ultra-high throughput fashion and by cultivation of broad diversity in our approches.
Initial situation:
Aluminum is an often-used building material in modern architecture, not only for construction but as well for facades and decorative elements. In the 1950th and 1960th, after World War II, many buildings in Germany were constructed with aluminum or contain elements of colored anodized aluminum. In the last years a larger number of these buildings are increasingly in the sight of conservation works including the aluminum parts such as window frames or facade coverings.
Damaged Aluminum Surfaces:
Common damages are a change of color or gloss changes through weathering processes, drill holes or marks due to later modifications, scratches in the anodized layer due to extensive wear e.g. at handrails or door handles.
To repair damaged aluminum surfaces, there are usually two options: smaller damaged areas are repaired by using a touch-up pen. In case of larger damages, the complete re-anodization is necessary. This includes to de-anodize the surface with cleaning and grinding the whole aluminum object. Both possibilities are disadvantageous for the objects. The touch-up pen often does not match the color of the original surface together with an insufficient corrosion protection for outdoors. While the newly anodized surface differs in color and gloss from the originally applied color.
Research Approach:
The whole procedure contrasts with the principal approach in conservation which aims to intervene as less as possible, in case of the conservation of an object. To fulfill this approach in a more appropriate way the research project focuses on a mobile and partial application for colored, anodized aluminum parts.
To anodize aluminum the application of an electrolyte onto the surface together with sufficient voltage and current is necessary. Generally diluted sulfuric acid is used as electrolyte. Different possibilities are examined to enable the mobile application of the electrolyte, e. g. the application by producing a gel matrix or like in electroplating by pen or brush wrapped with a fleece fabric.
Experimental part:
First experiments are conducted to examine the structure of the anodized layer in relation with proper cleaning, anodization time with applied voltage and current and the coloring process. The aim was to reduce the preparation procedure and the anodization time as much as possible to facilitate the mobile application.
Examinations with Keyence microscope, Eddy current testing and REM are performed to characterize the layers. The results are shown in table 1. A clear connection between proper cleaning, anodization time, voltage and amperage and the achieved thickness of the anodized layer is significant. Cracks in the layer show that raising the voltage and amperage results in thicker layers but as well in a crumbled and less stable anodized surface.
Gel preparation:
In addition to the anodization process with a liquid e.g. sulfuric acid a gel application is tested to prevent the electrolyte from rinsing down during the mobile application. For this purpose, several gel-forming agents are tested together with their stability in acid systems. It was observed, that the consistency of the gels varies dependent of the time.
Conductivity:
The conductivity of sulfuric acid combined with different gel-systems was measured and compared in order to predict the possible growth of layers during anodic oxidation process.
Further steps:
Determination and optimization of application parameters like voltage, amperage and anodization-time to build up a preferably stable and sufficient thick anodized layer. Examination of gel preparation to guarantee a stable product, enforcing with textile tape for easy application.
Leachiing tests - a useful tool for the environmental impact assessment of construction products?
(2018)
Construction products and waste materials used for construction can be in contact with the environment and may release potential harmful compounds. Information on the total content of these substances in the product is not sufficient to assess its envrionmental impact since it does not consider realistic exposure conditions.The impact of these compounds is often assessed by using the total content in the product. This estimation lacks realistic exposure conditions.
Concerning the pathway to soil and groundwater by contact with rain or seepage water leaching tests, which were developed and standardized by the European Committee for Standardization, are available. While for secondary construction products and waste this investigation of the leaching behaviour is standard procedure and is already part of regulation in Germany (draft ordinance on reuse of mineral waste) and within Europe (landfill directive) the release from primary construction products got in the focus more recently. Several monitoring studies found unexpected high concentrations of substances used as herbicides and fungicides in surface water and stormwater originating from urban areas. As some of these compounds are even banned for the use in agricultural applications in Europe alternative sources as roof materials and façade coatings exposed to rain were suggested. Further field and laboratory tests confirmed construction products as sources of these substances in water.
The aim of this presentation is to show exemplary results of existing leaching methods and underline the strength and weaknesses of the test system with selected examples from our work. We especially draw the attention to the research which is still needed to close the gap between the results of leaching experiments and the subsequent risk assessment of the products.
A non-invasivemethod has been carried out to show the capabilities and limitations of Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) for identifying of colourants and binders in modern reverse glass paintings. For this purpose, the reverse glass paintings “Zwei Frauen am Tisch” (1920–22), “Bäume” (1946) (both by Heinrich Campendonk), “Lofoten” (1933) (Edith Campendonk-van Leckwyck) and “Ohne Titel” (1954) (Marianne Uhlenhuth), were measured. In contrast to other techniques (e.g. panel and mural painting), the paint layers are applied in reverse succession. In multi-layered paint systems, the front paint layer may no longer be accessible. The work points out the different spectral appearance of a given substance (gypsum, basic lead white) in reverse glass paintings. However, inverted bands, band overlapping and derivative-shaped spectral features can be interpreted by comparing the spectra fromthe paintingswith spectra frompure powders and pigment/linseed oil mock-ups. Moreover, the work focuses on this method's capabilities in identifying synthetic organic pigments (SOP). Reference spectra of three common SOP (PG7, PY1, PR83) were obtained from powders and historical colour charts.We identified PR83 and PY1 in two reverse glass paintings, using the measured reference spectra. The recorded DRIFTS spectra of pure linseed oil, gum Arabic, mastic, polyvinyl acetate resin and bees wax can be used to classify the binding media of the measured paintings.
The presentation gives an overview about the use of ecotoxicity testing in assessment of waste. Especially in cases with unknown composition this kind of test are useful. Recently, the assessment of the hazard property HP 14 "ecotoxicity" for the labelling of waste was published. The labelling procedure is explained in detail.
Zearalenone (ZEN) and its phase II sulfate and glucoside metabolites have been detected in food and feed commodities. After consumption, the conjugates can be hydrolyzed by the human intestinal microbiota leading to liberation of ZEN that implies an underestimation of the true ZEN exposure. To include ZEN conjugates in routine analysis, reliable standards are needed, which are currently not available. Thus, the aim of the present study was to develop a facilitated biosynthesis of ZEN-14-sulfate, ZEN-14-glucoside and ZEN-16-glucoside. A metabolite screening was conducted by adding ZEN to liquid fungi cultures of known ZEN conjugating Aspergillus and Rhizopus strains. Cultivation conditions and ZEN incubation time were varied. All media samples were analyzed for metabolite formation by HPLC-MS/MS. In addition, a consecutive biosynthesis was developed by using Fusarium graminearum for ZEN biosynthesis with subsequent conjugation of the toxin by utilizing Aspergillus and Rhizopus species. ZEN-14-sulfate (yield: 49%) is exclusively formed by Aspergillus oryzae. ZEN-14-glucoside (yield: 67%) and ZEN-16-glucoside (yield: 39%) are formed by Rhizopus oryzae and Rhizopus oligosporus, respectively. Purities of ≥73% ZEN-14-sulfate, ≥82% ZEN-14-glucoside and ≥50% ZEN-16-glucoside were obtained by 1H-NMR. In total, under optimized cultivation conditions, fungi can be easily utilized for a targeted and regioselective synthesis of ZEN conjugates.
The presentation gives an overview about the use of ecotoxicity testing in assessment of waste. Especially in cases with unknown composition this kind of test are useful. Recently, the assessment of the hazard property HP 14 "ecotoxicity" for the labelling of waste was published. The labelling procedure is explained in detail.