Microplastics have been detected in freshwaters all over the world in almost all samples, and ecotoxicological studies have shown adverse effects of microplastics on organisms. However, no risk assessment of microplastics has been performed specifically in freshwater so far. The aim of the present study was therefore to review all exposure and ecotoxicity data available for microplastics in freshwaters and to perform a preliminary probabilistic risk assessment. The exposure probability distribution was based on 391 concentrations measured in Asia, Europe, and North America. Because exposure data are mainly available in particle number-based metrics but results from hazard studies are mostly mass-based, the hazard results were converted into particle number concentrations. A statistical analysis of the hazard data showed that there was no significant influence of particle shape or type of polymer on the no-observed-effect concentration. The predicted-no-effect concentration (PNEC) was calculated as the fifth percentile of the probabilistic species sensitivity distribution, based on 53 values from 14 freshwater species, to have a mode of 7.4 Â 10 5 particles Á m À3 (25th and 75th quantiles of 6.1 Â 10 5 and 1.3 Â 10 6 particles Á m À3 , respectively). The exposure probability distribution was divided by the PNEC probability distribution to calculate risk characterization ratios (RCRs), with modes of 1.3 Â 10 À6 in North America, 3.3 Â 10 À6 in Europe, and 4.6 Â 10 À3 in Asia. Probability distributions associated with the RCRs showed that ecological risks cannot be entirely excluded in Asia, where 0.4% of the RCR values were above 1. Environ Toxicol Chem 2019;38:436-447. C 2018

Microplastic fibers (MPF) have been found to be a major form of microplastic in freshwaters and washing of synthetic textiles has been identified as one of their main sources. The aim of this work was to use a panel of twelve different textiles of representative fiber and textile types to investigate the source(s) of the MPF released during washing. Using standardized washing tests, textile swatches tailored using five different cutting/sewing methods were washed up to 10 times. The MPF quantity and fiber length were determined using image analysis. The 12 textiles demonstrated a great variability in MPF release, ranging from 210 to 72'000 MPF/g textile per wash. The median MPF length ranged from 165 µm to 841 µm. The number of released MPF was influenced by the cutting method that scissor-cut samples released 3 -21 times higher numbers of MPF the laser-cut samples. The textiles with mechanically processed surfaces (i.e. fleece) released significantly more (p-value < 0.001) than the textiles with unprocessed surfaces. For all textiles, the MPF release decreased with repeated wash cycles and a small continuous fiber release was observed after 5-6 washings, accompanied by a slight increase in fiber length. The decrease in the number of MPF released is likely caused by depletion of the production-inherited MPFs trapped within the threads or the textile structure. The comparison of MPF release from laser-cut samples, which had sealed edges, and the other cutting methods allowed us to separate the contributions of the edge-and surface-sourced fibers from the textiles to the total release. On average, 84% (range 49-95%) of the MPF release originated from the edges, highlighting the importance of the edge-to-surface ratio when comparing different release studies. The large contribution of the edges to the total release offers options for technical solutions which have the possibility to control MPF formation throughout the textile manufacturing chain by using cutting methods which minimize MPF formation.

The pathogenesis of inflammatory bowel disease (IBD) might be related to the local inflammatory damage and the dysbacteriosis of intestinal flora. Probiotics can regulate the intestinal flora and ameliorate IBD. The probiotic Bacillus subtilis strain B. subtilis JNFE0126 was used as the starter of fermented milk. However, the therapeutic effects of B. subtilis-fermented milk on IBD remain to be explored. In this research, the therapeutic effect of B. subtilis-fermented milk on dextran sulfate sodium salt (DSS)-induced IBD mouse model was evaluated. Besides, the expression of pro-inflammatory/anti-inflammatory cytokines, the proliferation of the intestinal stem cells, and the reconstruction of the mucosa barrier were investigated. Finally, alteration of the gut microbiota was investigated by taxonomic analysis. As shown by the results, the disease activity index (DAI) of IBD was significantly decreased through oral administration of B. subtilis (JNFE0126)-fermented milk, and intestinal mucosa injury was attenuated. Moreover, B. subtilis could reduce the inflammatory response of the intestinal mucosa, induce proliferation of the intestinal stem cell, and promote reconstruction of the mucosal barrier. Furthermore, B. subtilis could rebalance the intestinal flora, increasing the abundance of Bacillus, Alistipes, and Lactobacillus while decreasing the abundance of Escherichia and Bacteroides. In conclusion, oral administration of the B. subtilis-fermented milk could alleviate DSS-induced IBD via inhibition of inflammatory response, promotion of the mucosal barrier reconstruction, and regulation of the intestinal flora.

Nanoplastics (defined here as plastic particles smaller than 1000 nm) released during the daily use of plastic products are gaining increasing attention due to their potential effects on human and environmental health. Formation of nanoplastics has been reported so far for diverse plastic products under varying conditions of use. The washing of synthetic textiles has been identified as an important source of microplastic fibers (MPF) released to the environment. In addition, abrasion of textiles was shown to induce further fragmentation of fibers and subsequent formation of much smaller and shorter fibrils. The aim of this work was to identify whether washing and wearing of textiles also results in the formation of nanoplastics. We designed washing and abrasion experiments to investigate the morphology, number, and size of micro-and nanoplastics released from polyester textiles. Using a combination of techniques including scanning transmission X-ray microspectroscopy (STXM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA), we were able to quantify nanoplastics (average hydrodynamic diameter 173−188 nm), microplastic fibrils (diameter 3 ± 1 μm, length 20−160 μm), and MPFs (diameter 16 ± 7 μm, length up to 5 mm). The presence of polyester nanoplastics was confirmed by the near edge X-ray absorption fine spectra (NEXAFS) of the nanoparticles in the abrasion and washing samples for particles larger than 100 nm. We estimated that in the abraded samples, 1 g of fleece textile released an average of 2.1× 10 11 nanoplastic particles (1.4 mg), 1.4 × 10 4 MPFs (1.0 mg), and 5.3 × 10 5 fibrils (0.5 mg) based on SEM images and NTA. In the nonabraded samples, 1 g of textile released an average of 3.3 × 10 11 nanoplastic particles (2.1 mg), 2.8 × 10 3 MPFs (0.2 mg), and no fibrils. The present study is the first to show a significant release of polyester nanoplastics during the washing and abrasion of synthetic textiles.