Auflistung nach Autor:in "Kittner, Maria"

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    A new concept for the ecotoxicological assessment of plastics under consideration of aging processes
    (2023) Kittner, Maria; Isernhinke, Lisa; Altmann, Korinna; Braun, Ulrike; Lukas, Marcus
    Microplastics are widely distributed in aquatic and terrestrial environments, but up tonow less is known about (eco)toxicological impacts under realistic conditions. Researchso far has focused mainly on impacts on organisms by fresh, single-origin plasticfragments or beads. However, plastics found in the environment are complex incomposition, this means different polymer types and sources, with and withoutadditives and in all stages of age, and therefore, in a more or less advanced stage ofdegradation. For oxidized degradation products that might be released from plasticmaterials during aging, there is a lack of information on potentially adverse effects onaquatic biota. The latter is of particular interest as oxidized degradation products mightbecome more water soluble due to higher polarity and are more bioavailable, therefore.The present study focused on plastic leachates of polystyrene (PS) and polylactic acid(PLA), which were derived from alternating stress by hydrolysis and ultraviolet (UV)radiation-representing a realistic scenario in the environment. Test specimens of PS,PLA, or a PLA/PS layer (each 50%) were alternately exposed to UV radiation for 5 daysfollowed by hydrolysis for 2 days, for several weeks alternating. Ecotoxicological effectsof the storage water (artificial freshwater) of the test specimens and additionally, in asecond experimental setup, the effects of five potential polymer degradation productswere detected by 72 h algae growth inhibition tests withDesmodesmus subspicatus.Results clearly indicate inhibitory effects on algae growth by contaminants in thestorage water of stressed plastics with increasing growth inhibition of proceedinghydrolysis and UV stress times. Different polymers caused variable inhibitions of algaegrowth with stronger inhibitions by PS and less effects by PLA and the mixed layer ofboth. Moreover, not microplastic particles but the resulting dissolved degradationproducts after aging caused theecotoxicological effectsââą Ìwith strong effects by theoxidized degradation products. The existing data highlight the relevance of plastic agingas a framework for microplastic ecotoxicity evaluation and allow a proof of concept. © 2023 The Authors.
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    Decomposability versus detectability: First validation of TED-GC/MS for microplastic detection in different environmental matrices
    (2023) Kittner, Maria; Eisentraut, Paul; Braun, Ulrike
    A fast method for microplastic detection is thermal extraction desorption-gas chromatography/mass spectrometry (TED-GC/MS), which uses polymer-specific thermal decomposition products as marker compounds to determine polymer mass contents in environmental samples. So far, matrix impacts of different environmental matrices on TED-GC/MS performance had not yet been assessed systematically. Therefore, three solid freshwater matrices representing different aquatic bodies with varying organic matter contents were spiked with a total of eight polymers. Additionally, for the first time, the two biodegradable polymers polybutylene adipate terephthalate (PBAT) and polylactide (PLA) were analysed using TED-GC/MS. The methodological focus of this work was on detectability, quality of signal formation as well as realisation of quantification procedures and determination of the limit of detection (LOD) values. Overall, TED-GC/MS allowed the unambiguous detection of the environmentally most relevant polymers analysed, even at low mass contents: 0.02wt% for polystyrene (PS), 0.04wt% for the tyre component styrene butadiene rubber (SBR) and 0.2wt% for polypropylene (PP), polyethylene (PE) and PBAT. Further, all obtained LOD values were increased in all matrices compared to the neat polymer without matrix. The LOD of the standard polymers were increased similarly (PS: 0.21-0.34 (micro)g, SBR: 0.27-0.38 (micro)g, PP: 0.32-0.36 (micro)g, PMMA: 0.64-1.30 (micro)g, PET: 0.90-1.37 (micro)g, PE: 3.80-6.99 (micro)g) and their decompositions by radical scission processes were not significantly influenced by the matrices. In contrast, matrix-specific LOD increases of both biodegradable polymers PBAT (LOD: 1.41-7.18 (micro)g) and PLA (0.84-20.46 (micro)g) were observed, probably due to their hetero-functional character and interactions with the matrices. In conclusion, the TED-GC/MS performance is not solely determined by the type of the polymers but also by the composition of the matrix. © 2023 Wiley VCH GmbH
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