Filtern
Dokumenttyp
- Zeitschriftenartikel (16)
- Vortrag (4)
- Beitrag zu einem Tagungsband (2)
- Beitrag zu einem Sammelband (1)
- Sonstiges (1)
- Posterpräsentation (1)
- Forschungsbericht (1)
Schlagworte
- TED-GC/MS (10)
- Microplastics (7)
- Microplastic (6)
- Mikroplastik (4)
- Mikroplastik-Analytik (2)
- Probennahme (2)
- APTES (1)
- Adsorbtion (1)
- Aktivkohle (1)
- Algae growth test (1)
Organisationseinheit der BAM
Eingeladener Vortrag
- nein (4)
This study reflects typical consumer textile washing behaviour while taking into account existing standards in the household appliance and garment industries. Two garments were washed repeatedly with artificial dirt and detergent 30 times. The collected washing water was separated using fractional filtration. Textile physical tests were used to follow property changes of the garments, the microplastic release is determined using thermoextraction/desorbtion–gas chromatography/mass spectrometry and the total organic carbon was measured as a sum parameter for the organic bonded carbon. This article shows the importance of a reality‐based approach when investigating microplastics of textile origin in the laundry care process. Deposits of detergent and dirt on the textiles were detected. The total mass of sieve residues was much higher than the release of synthetic polymers. The cotton content of the garments causes a much higher fibre release than synthetic fibres. Both will lead to false results by purely gravimetric analysis because nonpolymer fibres will be included microplastic mass. The results cannot be generalised only by the main polymer type, knowledge of the textile construction must be included for final evaluation.
A comprehensive characterization of the thermal and the fire behaviour is presented for polypropylene (PP) flax compounds containing ammonium polyphosphate (APP) and expandable graphite as fire retardants. Thermogravimetry coupled with an evolved gas analysis (TG-FTIR) was performed to ensure a significant thermal analysis. The fire response under forced flaming conditions was studied using a cone calorimeter. The external heat flux was varied between 30 and 70 kW m-2 so that the results could be evaluated for different fire scenarios and tests. Different flammability tests (UL 94, limiting oxygen index, glow wire test, GMI 60261) were performed and the results compared with the cone calorimeter data. The different char forming mechanisms are described and the resulting fire retardancy is classified. The successful and ecological friendly fire retardancy is a technological breakthrough for PP/flax biocomposites.
In this study, carried out within the Joint Danube Survey 4, a comprehensive microplastic screening in the water column within a large European river basin from its source to estuary, including major tributaries, was realized. The objective was to develop principles of a systematic and practicable microplastic monitoring strategy using sedimentation boxes for collection of suspended particulate matter followed by its subsequent analysis using thermal extraction desorption-gas chromatography/mass spectrometry. In total, 18 sampling sites in the Danube River Basin were investigated. The obtained suspended particulate matter samples were subdivided into the fractions of >100 μm and <100 μm and subsequently analyzed for microplastic mass contents. The results showed that microplastics were detected in all samples, with polyethylene being the predominant polymer with maximum contents of 22.24 μg/mg, 3.23 μg/mg for polystyrene, 1.03 μg/mg for styrene-butadiene-rubber, and 0.45 μg/mg for polypropylene. Further, polymers such as different sorts of polyester, polyacrylates, polylactide, and natural rubber were not detected or below the detection limit. Additional investigations on possible interference of polyethylene signals by algae-derived fatty acids were assessed. In the context of targeted monitoring, repeated measurements provide more certainty in the interpretation of the results for the individual sites. Nevertheless, it can be stated that the chosen approach using an integrative sampling and determination of total plastic content proved to be successful.
Microplastics are small plastic fragments that are widely distributed in marine and terrestrial environments. While the soil ecosystem represents a large reservoir for plastic, research so far has focused mainly on the impact on aquatic ecosystems and there is a lack of information on the potentially adverse effects of microplastics on soil biota. Earthworms are key organisms of the soil ecosystem and are due to their crucial role in soil quality and fertility a suitable and popular model organism in soil ecotoxicology.
Therefore, the aim of this study was to gain insight into the effects of environmentally relevant concentrations of microplastics on the earthworm Eisenia andrei on multiple levels of biological organization after different exposure periods. Earthworms were exposed to two types of microplastics: (1) polystyrene-HBCD and (2) car tire abrasion in natural soil for 2, 7, 14 and 28 d. Acute and chronic toxicity and all subcellular investigations were conducted for all exposure times, avoidance behavior assessed after 48 h and reproduction after 28 d. Subcellular endpoints included enzymatic biomarker responses, namely, carboxylesterase, glutathione peroxidase, acetylcholinesterase, glutathione reductase, glutathione S-transferase and catalase activities, as well as fluorescence-based measurements of oxidative stress-related markers and multixenobiotic resistance activity. Multiple biomarkers showed significant changes in activity, but a recovery of most enzymatic activities could be observed after 28 d. Overall, only minor effects could be observed on a subcellular level, showing that in this exposure scenario with environmentally relevant concentrations based on German pollution levels the threat to soil biota is minimal. However, in areas with higher concentrations of microplastics in the environment, these results can be interpreted as an early warning signal for more adverse effects. In conclusion, these findings provide new insights regarding the ecotoxicological effects of environmentally relevant concentrations of microplastics on soil organisms.
Discoloration Effects of High-Dose gamma-Irradiation and Long-Term Thermal Aging of (U) HMW-PE
(2017)
Two polyethylene types with ultra-high (UHMWPE) and high molecular weight (HMW-PE) used as neutron radiation shielding materials in casks for radioactive waste were irradiated with doses up to 600 kGy using a 60Co gammasource. Subsequently, thermal aging at 125∘C was applied for up to one year. Degradation effects in the materials were characterized using colorimetry, UV-Visspectroscopy, IR spectroscopy, and DSC. Both materials exhibited a yellowing upon irradiation.The discoloration of UHMW-PE disappeared again after thermal aging.Therefore, the yellowing is assumed to originate fromannealable color centers in the formof free radicals that are trapped in the crystalline regions of the polymer and recombine at elevated temperatures. For the antioxidantcontaining HMWPE, yellowing was observed after both irradiation and thermal aging. The color change was correlated mainly to decomposition products of the antioxidant in addition to trapped radicals as in UHMW-PE. Additionally, black spots appeared after thermal aging of HMW-PE.
Water treatment with activated carbon (AC) is an established method for the removal of organic micropollutants and natu ral organic matter. However, it is not yet possible to predict the removal of individual pollutants. An appropriate material characterization, matching adsorption processes in water, might be the missing piece in the puzzle. To this end, this study examined 25 diferent commercially available ACs to evaluate their material properties. Frequently reported analyses, including N2 adsorption/desorption, CHNS(O), point of zero charge (PZC) analysis, and X-ray photoelectron spectroscopy, were conducted on a selected subset of powdered ACs. Inorganic elements examined using X-ray fuorescence and X-ray difraction spectroscopy revealed that relative elemental contents were distinctive to the individual AC’s raw material and activation procedure. This study also is the frst to use thermogravimetric analysis (TGA) coupled to Fourier-transform infrared spectroscopy (FTIR) to conduct quantitative analyses of functional surface oxygen groups (SOGs: carboxylic acid, anhydride, lactone, phenol, carbonyl, and pyrone groups) on such a large number of ACs. The comparably economical TGA method was found to provide good surrogates for the PZC by pyrolytic mass loss up to 600 ◦C (ML600), for the oxygen content by ML1000 and for the carbon content by oxidation. Mass loss profles depict the AC’s chemistry like fngerprints. Furthermore, we found that SOG contents determined by TGA-FTIR covered a wide individual range and depended on the raw material and production process of the AC. TGA and TGA-FTIR might therefore be used to identify the suitability of a particular AC for a variety of target substances in diferent target waters. This can help practitioners to control AC use in waterworks or wastewater treatment plants.
An investigation of microplastic (MP) occurrence in a municipal wastewater treatment plant (WWTP) effluent with tertiary treatment was carried out. Representative sample volumes of 1 m3 were taken by applying a fractionated filtration method (500, 100, and 50 µm mesh sizes). The detection of MP mass fractions by thermal extraction desorption–gas chromatography/mass spectrometry (TED-GC/MS) was achieved without the previously required additional sample pretreatment for the first time. Different types of quantification methods for the evaluation of TED-GC/MS data were tested, and their accuracy and feasibility have been proven for real samples. Polyethylene, polystyrene, and polypropylene were identified in effluent samples. The polymer mass content varied significantly between 5 and 50 mg m−3. A correlation between the MP load and the quantity of suspended matter in the WWTP effluents, particle size distribution, particle type, and operation day (i.e., weekday, season, and capacity) was not found. It can be concluded that a meaningful assessment of WWTPs requires a comprehensive sampling campaign with varying operation conditions.
Tire wear (TW) constitutes a significant source of microplastic in terrestrial ecosystems. It is known that particles emitted by roads can have an effect up to 100 m into adjacent areas. Here, we apply for the first-time thermal extraction desorption gas chromatography-mass spectrometry (TED-GC/MS) to determine TW in soil samples by detection of thermal decomposition products of styrene-butadiene rubber (SBR), without additional enrichment. Additionally, zinc contents were determined as an elemental marker for TW. Mixed soil samples were taken along three transects along a German motorway in 0.3, 2.0, and 5.0 m distance from the road. Sampling depths were 0–2, 2–5, 5–10, and 10–20 cm. Four fine fractions, 1 000–500, 500–100, 100–50, and <50 μm, were analyzed.
TW contents based on SBR ranged from 155 to 15 898 mg kg−1. TW contents based on zinc were between 413 and 44 812 mg kg−1. Comparison of individual values of SBR and zinc reveals SBR as a more specific marker. Results confirm that most TW ends up in the topsoil within a 2 m distance.
The sampling strategy resulted in representative data for a larger area. Standard deviations of quadruple TED-GC/MS determination of SBR were <10% for all grain size fractions. TED-GC/MS is a suitable analytical tool for determining TW in soil samples without the use of toxic chemicals, enrichment, or special sample preparation.
Microplastic (MP) contamination in natural water circulation is a concern for environmental issues and human health. Various types of polymer materials have been identified and were detected in MP analytic test procedures. Beyond MP polymer type, particle size and form play a major role in water analysis due to possible negative toxicologic effects on flora and fauna. However, the correct quantitative measurement of MP size distribution over several orders of magnitude is strongly influenced by sample preparation, filtration materials and processes, and microanalytical techniques, as well as data acquisition and analysis. In this paper, a reference methodology is presented aiming at an improved quantitative analysis of MP particles. An MP analysis workflow is demonstrated including all steps from reference materials to sample preparation, filtration handling, and MP particle size distribution analysis. Background-corrected particle size distributions (1–1000 µm) have been determined for defined polyethylene (PE) and polyethylene terephthalate (PET) reference samples. Microscopically measured particle numbers and errors have been cross-checked with the total initial mass. In particular, defined reference MP samples (PE, PET) are initially characterized and applied to filtration experiments. Optical microscopy imaging on full-area Si filters with subsequent image analysis algorithms is used for statistical particle size distribution analysis. To quantify the effects of handling and filtration, several blind tests with distilled water are carried out to determine the particle background for data evaluation. Particle size distributions of PE and PET reference samples are qualitatively and quantitatively reproduced with respect to symmetry, and maximum and cut-off diameter of the distribution. It is shown that especially MP particles with a radius of >50 µm can be detected and retrieved with high reliability. For particle sizes <50 µm, a significant interference with background contamination is observed. Data from blank samples allows a correction of background contaminations. Furthermore, for enhanced sampling statistics, the recovery of the initial amount of MP will be qualitatively shown. The results are intended as an initial benchmark for MP analytics quality. This quality is based on statistical MP particle distributions and covers the complete analytic workflow starting from sample preparation to filtration and detection. Microscopic particle analysis provides an important supplement for the evaluation of established spectroscopic methods such as Fourier-transform infrared spectroscopy or Raman spectroscopy.