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Plastics are a diverse group of materials used in packaging, construction, medical applications, and many more. Due to their favourable properties their production and consequently their input into natural systems has increased drastically over the last decades. In the environment (photo-)oxidation processes and mechanical abrasion may then lead to the decomposition of the plastics. During this process microplastics (<5 mm) are formed. It has been noted that xenobiotics which are present in the same compartments can sorb to microplastics. However, knowledge on this topic is still limited. The work presented here aimed to investigate the sorption of the type 2 diabetes drug metformin and the triazole fungicide difenoconazole to virgin polyamide (PA), polypropylene (PP), and polystyrene (PS). Additionally, sorption to cryo-milled PP and acid-treated PA was studied. The latter was also characterised by Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and dynamic scanning calorimetry (DSC). Sorption experiments were planned on the basis of a full factorial design with agitation, salinity, and pH value as parameters. Results of the study revealed that metformin did not show any affinity towards the tested materials. Difenoconazole however, sorbed to all microplastics. Data analysis showed that agitation is the main influencing factor, whereas salinity and the pH value held little to no significance. Mechanical and chemical treatment of the polymers led to enhanced sorption of difenoconazole. Long-term sorption experiments confirmed the hypothesis that particle size strongly influences the time until sorption-desorption equilibrium is reached.
MaUS is an acronym for ”Material und Umweltsimulationen“. Plastics are in the focus of environmental politics due to their long term behaviour and therefore to their persistence. Not only that they appear as visible contaminants in the sea and on the beach, but their unknown behaviour concerning their additives as well as the related transformation products are anxious. Therefore, we wish to establish a certified reference method to provide a method for testing plastics.
Aim of this project is the development of fast motion standard reference methods for testing plastics regarding to their environmental compatibility. To establish these testing methods, we use polystyrene (PS) and polypropylene (PP) with environmental relevant brominated flame retardants, known for their persistent bioaccumulative and toxic (PBT) properties. In case of PS the material contains 1 wt% of 1,2,5,6,9,10-hexabromocyclododecan (HBCD) and in case of PP 0.1 wt% bromodiphenylether (BDE-209), which is known as a substance of very high concern (SVHC). Furthermore, we use polycarbonate (PC), which is still used as material in baby flasks and releases Bisphenol A (BPA), an estrogenic active substance.
As an additional material PTFE is used for its importance as a source for two ubiquitous environmental substances (PFOS and PFOA), whose toxicological effects are still incompletely known.
The focus in this current work is set on the transfer of potential pollutants out of applied materials mentioned above into environmental compartments like water or soil. Here an accelerated aging concept should be developed to shortened time consuming natural processes. For these resulting simulations we use a programmable weathering chamber with dry and wet periods and with high and low temperatures. These programmes run for several weeks and according to a defined sampling schedule we take water samples, run a clean-up procedure by SPE (Molecular imprinted polymers (MiPs) resp. polymer based cartridges (Waters Oasis HLB)) and analyse them by HPLC-UV resp. LC-MS/MS. Of most interest in case of flame retardants are photocatalytic transformation products. Therefore, we conduct a non-target-screening resp. a suspected target-screening by LC-MS/MS and HRMS.