Small polymer particles with a diameter of less than 5 mm called microplastics find their way into the environment from polymer debris and industrial production. Therefore a method is needed to ...identify and quantify microplastics in various environmental samples to generate reliable concentration values. Such concentration values, i.e. quantitative results, are necessary for an assessment of microplastic in environmental media. This was achieved by thermal extraction in thermogravimetric analysis (TGA), connected to a solid-phase adsorber. These adsorbers were subsequently analysed by thermal desorption gas chromatography mass spectrometry (TDS-GC-MS). In comparison to other chromatographic methods, like pyrolyse gas chromatography mass spectrometry (Py-GC-MS), the relatively high sample masses in TGA (about 200 times higher than used in Py-GC-MS) analysed here enable the measurement of complex matrices that are not homogenous on a small scale. Through the characteristic decomposition products known for every kind of polymer it is possible to identify and even to quantify polymer particles in various matrices. Polyethylene (PE), one of the most important representatives for microplastics, was chosen as an example for identification and quantification.
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•Using a thermal decomposition method for analysing PE microplastics in environmental matrices in one step.•Direct measuring without a pre selection.•Identification and quantification of polymers in environmental samples.
The occurrence of microplastic (MP) in food products, such as beverages in plastic bottles, is of high public concern. Existing analytical methods focus on the determination of particle numbers, ...requiring elaborate sampling tools, laboratory infrastructure and generally time-consuming imaging detection methods. A comprehensive routine analysis of MP in food products is still not possible. In the present work, we present the development of a smart filter crucible as sampling and detection tool. After filtration and drying of the filtered-off solids, a direct determination of the MP mass content from the crucible sample can be done by thermal extraction desorption gas chromatography mass spectroscopy (TED-GC/MS). The new filter crucible allows a filtration of MP down to particle sizes of 5 µm. We determined MP contents below 0.01 µg/L up to 2 µg/L, depending on beverages bottle type. This may be directly related to the bottle type, especially the quality of the plastic material of the screw cap. Dependent on the plastic material, particle formation increases due to opening and closing operations during the use phase. However, we have also found that some individual determinations of samples were subjected to high errors due to random events. A conclusive quantitative evaluation of the products is therefore not possible at present.
The interaction of microcroplastics (MP) with dissolved organic matter, especially humic substances, is of great importance in understanding the behavior of microplastics in aquatic ecosystems. ...Surface modification by humic substances plays an essential role in transport and interaction of MP with abiotic and biotic components. Previous studies on the interaction between MP and humic substances were largely based on a model compound, humic acid (Sigma‐Aldrich). In our work, we therefore investigated the interaction of natural organic matter (NOM) sampled from a German surface water with low‐density polyethylene particles (LDPE). High‐pressure size exclusion chromatography (HPSEC) and UV/vis absorption and fluorescence spectroscopy were used to characterize the incubation solutions after modifications due to the presence of LDPE, and Raman spectroscopy was used to characterize the incubated microplastics. While the studies of the solutions generally showed only very small effects, Raman spectroscopic studies allowed clear evidence of the binding of humic fractions to MP. The comparison of the incubation of NOM and a lignite fulvic acid which also was tested further showed that specific signatures of the humic substances used could be detected by Raman spectroscopy. This provides an elegant opportunity to conduct broader studies on this issue in the future.
Natural organic material (NOM) and a lignite‐derived fulvic acid (both less than 100 mg L−1 organic carbon) were incubated with microplastic (LDPE, <75 µm) for 3 days. Raman spectroscopic examination of the filtered and washed particles displayed an overlap of the Raman spectra of LDPE with the fluorescence emission of the humic substances used, each of which exhibited a specific spectral response. Thus, Raman spectroscopy offers a direct, simple method for the detection of humic substances adsorbed on microplastics.
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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 m
3
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.
Uncertainties in estimates of soil carbon (C) stocks and sequestration result from major gaps in knowledge of C storage in soils, land-use history, the variability of field measurements, and ...different analytical approaches applied. In addition, there is a lack of long-term datasets from relevant land-use systems. As in many European countries, a national database on soil organic carbon (SOC) including all relevant information for the determination of soil C stocks is likewise missing in Germany. In this paper, we summarize and evaluate the present state of knowledge on organic-C contents/pools in soils of Germany and discuss the need for the acquisition and access to new data on soil organic carbon.Despite the number of agricultural sites under permanent soil monitoring, regional surveys on SOC, comprehensive ecosystem studies, and long-term field experiments, there is a striking lack of data in Germany particularly with regard to agricultural soils. Apart from a missing standardization of methods and homogeneous baseline values, the implementation of a periodic, nation-wide soil inventory on agricultural soils is required in order to simultaneously record information on land use, land-use change, and agricultural practice. In contrast, the existing national inventory of forest soils provides information on C-stock changes in forest soils, although there is some concern with regard to the representativeness of the sampling design to adequately address the problem of spatial heterogeneity and temporal variability.It is concluded that the lack of comprehensiveness, completeness, actuality, data harmonization, and standardized sampling procedures will further prevent the establishment of a SOC database in Germany with regard to the monitoring of trends in soil C pools and fluxes and the assessment of long-term C-sequestration potentials of soils under different land use. A future soil inventory should represent the heterogeneity of organic matter through functionally different SOC pools, topsoil characteristics as well as content, pool, and flux data for the deeper mineral-soil compartments.
