The contamination of marine and freshwater ecosystems with plastic, and especially with microplastic (MP), is a global ecological problem of increasing scientific concern. This has stimulated a great deal of research on the occurrence of MP, interaction of MP with chemical pollutants, the uptake of MP by aquatic organisms, and the resulting (negative) impact of MP. Herein, we review the major issues of MP in aquatic environments, with the principal aims 1) to characterize the methods applied for MP analysis (including sampling, processing, identification and quantification), indicate the most reliable techniques, and discuss the required further improvements; 2) to estimate the abundance of MP in marine/freshwater ecosystems and clarify the problems that hamper the comparability of such results; and 3) to summarize the existing literature on the uptake of MP by living organisms. Finally, we identify knowledge gaps, suggest possible strategies to assess environmental risks arising from MP, and discuss prospects to minimize MP abundance in aquatic ecosystems.

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Raman microspectroscopy allows us to distinguish between synthetic and natural fibers in beverage samples.

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We examined the potential of stable-isotope Raman microspectroscopy (SIRM) for the evaluation of differently enriched C-labeled humic acids as model substances for soil organic matter (SOM). The SOM itself can be linked to the soil water holding capacity. Therefore, artificial humic acids (HA) with known isotopic compositions were synthesized and analyzed by means of SIRM. By performing a pregraphitization, a suitable analysis method was developed to cope with the high fluorescence background. Results were verified against isotope ratio mass spectrometry (IRMS). The limit of quantification was 2.1 × 10C/C for the total region and 3.2 × 10C/C for a linear correlation up to 0.25C/C . Complementary nanoscale secondary ion mass spectrometry (NanoSIMS) analysis indicated small-scale heterogeneity within the dry sample material, even though-owing to sample topography and occurring matrix effects-obtained values deviated in magnitude from those of IRMS and SIRM. Our study shows that SIRM is well-suited for the analysis of stable isotope-labeled HA. This method requires no specific sample preparation and can provide information with a spatial resolution in the micrometer range. Graphical abstract Analysis of the isotopic composition of humic acids by Raman microspectroscopy in combination with isotope ratio mass spectrometry and nanoscale secondary ion mass spectrometry.

Die Verunreinigung von Salz‐ und Süßwassersystemen durch Kunststoffe und insbesondere Mikroplastik (MP) stellt ein weltweites ökologisches Problem dar. Zahlreiche Studien beschäftigten sich mit dem Vorkommen von MP, der Wechselwirkung mit Schadstoffen, der Aufnahme durch aquatische Organismen und den daraus resultierenden Wirkungen. Dieser Aufsatz behandelt die wichtigsten Fragen in Bezug auf MP in aquatischen Systemen. Der Schwerpunkt liegt hierbei auf: 1) der Beschreibung der analytischen Methoden zur Probenahme, Aufbereitung, Identifikation und Quantifizierung von MP sowie deren Anwendbarkeit, Zuverlässigkeit und den benötigten Verbesserungen; 2) einer Abschätzung des MP‐Vorkommens sowie möglicher Hindernisse bei der Vergleichbarkeit unterschiedlicher Studien; 3) einer Zusammenfassung der bekannten Literatur zur Aufnahme von MP durch Organismen. Anschließend werden vorhandene Wissenslücken aufgezeigt, mögliche Strategien zur Bewertung der Umweltgefährdung vorgeschlagen und Perspektiven zur Reduzierung von MP in aquatischen Ökosystemen diskutiert.