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Abstract Microplastics (MPs) has gradually become a global environmental pollution problem and may harm human and animal health. In recent years, a large number of studies had shown that MPs had various toxicological effects on different organisms. At the same time, a number of studies had also shown that gut microbiota was closely related to host health and as a toxicity target for certain environmental pollutants including MPs. The fact is that more and more studies proved that MPs not only could interact with microorganism directly but also serve as a carrier for other pollutants and interacted with microorganism indirectly. In this review, we summarized the interactions between MPs and microorganisms as well as gut microbiota, and considered the possible impacts of MPs on environmental animal and human health, suggesting that the environmental microorganisms and the gut microbiota of animals were also the very important target for MPs. We hope that more studies pay more attention to focus on the relationship between MPs, gut microbiota, and environmental animals and human health in the future. Graphical abstract Unlabelled Image Highlights • Microplastics could interact with microorganisms as well as gut microbiota. • Microplastics may affect host health through effects on gut microbiota. • Effects of microplastics on gut microbiota need more attention. [ABSTRACT FROM AUTHOR]

Propamocarb (PM) is a widely used fungicide that affects lipid biosynthesis in fungi. In this study, we explored the effects of PM on mouse metabolism and gut microbiota-related pathways by exposing C57BL/6J mice to 1, 3, and 10 mg/L PM through drinking water for a duration of 10 weeks. We found that hepatic bile acids (BAs) were considerably increased in the PM-treated group. The transcription of genes related to BA synthesis and transportation were also markedly altered in the liver and the ileum; accordingly, serous BA profiles were changed. BAs are tightly associated with energy metabolism and the gut microbiota; as expected, we observed that hepatic glycolysis; β-oxidation; fatty acid transportation, release and synthesis; and triacylglycerol synthesis and transportation were significantly altered at the transcriptional level. Gut microbial community structures were significantly changed both in cecal contents and feces. Using Linear discriminant analysis Effect Size (LEfSe), we found that Chloroflexi, Bacteroidetes and Actinobacteria phyla; Prevotellaceae, Odoribacteraceae and Porphyromonadaceae families; and Butyricimonas, Oscillospira, Parabacteroides, Prevotella and Dorea genera enriched in PM-treated mice. Fecal metabolites involved in energy metabolism were likewise altered. In addition, the atherosclerosis-promoting molecule trimethylamine was significantly increased in feces, which induced a disturbance in the cardiac NO/NOS pathway and an increase in NF-κB transcriptional levels. Our findings indicated that chronic PM exposure induced disorders in enterohepatic metabolism and had potential to increase the risk of cardiovascular disease. [ABSTRACT FROM AUTHOR]

Reduction of surface-bound arsenate [As(V)] and subsequent release into the aqueous phase contribute to elevated As in groundwater. However, this natural process is not fully understood, especially in the presence of sulfate-reducing bacteria (SRB). Gaining mechanistic insights into solid-As(V)-SRB interactions motivated our molecular level study on the fate of nano-TiO 2 bound As(V) in the presence of Desulfovibrio vulgaris DP4, a strain of SRB, using incubation and in situ ATR-FTIR experiments. The incubation results clearly revealed the reduction of As(V), either adsorbed on nano-TiO 2 or dissolved, in the presence of SRB. In contrast, this As(V) reduction was not observed in abiotic control experiments where sulfide was used as the reductant. Moreover, the reduction was faster for surface-bound As(V) than for dissolved As(V), as evidenced by the appearance of As(III) at 45 h and 75 h, respectively. ATR-FTIR results provided direct evidence that the surface-bound As(V) was reduced to As(III) on TiO 2 surfaces in the presence of SRB. In addition, the As(V) desorption from nano-TiO 2 was promoted by SRB relative to abiotic sulfide, due to the competition between As(V) and bacterial phosphate groups for TiO 2 surface sites. This competition was corroborated by the ATR-FTIR analysis, which showed inner-sphere surface complex formation by bacterial phosphate groups on TiO 2 surfaces. The results from this study highlight the importance of indirect bacteria-mediated As(V) reduction and release in geochemical systems. [ABSTRACT FROM AUTHOR]

In the past two decades, numerous studies on dioxin concentrations in breast milk have been conducted in China. However, information concerning dioxin concentrations in breast milk from women living in e-waste recycling sites remains limited. Thus, this study aimed to evaluate health risk owing dioxin intake in e-waste recycling areas in China. In 2015, 42 mothers were recruited from an e-waste recycling site, and the same number of mothers were recruited from a reference site. We collected 10-mL breast milk samples from each participant. Breast milk concentrations of polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs) were significantly higher in the exposed group than in the reference group. The total toxic equivalents (TEQ) of PCDDs/DFs were 9.68 pg/g lipid in the exposed group, a value two times higher than those in the reference group (4.18 pg/g lipid). The estimated daily intake (EDI) of PCDD/DFs was calculated to assess the risk of dioxins through breastfeeding. The infant EDI level was two times higher in the exposed group (54.21 pg TEQ/kg body wt/day) than in the reference group (23.41 pg TEQ/kg body wt/day). Our findings suggest that mothers and their breastfeeding infants living in an e-waste recycling site were exposed to higher dioxin concentrations than those living in a reference site. Unlabelled Image • The dioxin concentrations in the exposed group were significantly higher than the reference group. • The infant EDI levels in the exposed group was 2 times higher than in the reference group. • The mothers and their breast-fed infants living in the exposed area higher body burden of dioxin [ABSTRACT FROM AUTHOR]

Arsenic (As) pollution in coastal wetland soil has attracted attention. However, how anaerobic microbes impact the fate of As in coastal wetland environments remains poorly understood. To elucidate underlying mechanisms of anaerobic microbes mediated As mobilization, incubation experiments were performed in this study. The results demonstrate that the concentrations of total dissolved As and As(III) were higher in biotic incubations compared with abiotic controls. The dissolved As(III) concentrations increased and reached maximum values of 11.0 ± 1.2 and 12.0 ± 1.1 μg/L for biotic incubations with and without additional sulfate, respectively. Sulfate and Fe reduction induced by anaerobic microbes were evidenced by the detection of sulfide and Fe(II) in biotic incubations. The sequential extraction results indicated that the content of crystalline Fe mineral fraction of As (As cry) increased and that of amorphous Fe mineral fraction of As (As amo) decreased in the solid phase. Therefore, the released As was attributed to microbially mediated reductive dissolution of amorphous Fe mineral matter and, after 40 days of incubation, the decreased As might be immobilized via re-adsorption onto, or co-precipitation with, the newly formed crystalline Fe minerals. The 16S rRNA results indicated that Proteobacteria , Chloroflexi , Actinobacteria , and Firmicutes constituted the majority of the bacterial community in biotic incubations. The sulfate-reducing bacterium Desulfocapsa induced sulfate reduction and further promoted the reduction and release of As in soils. This study provides insights into the mechanism for As mobilization and redistribution in coastal wetland soils. Unlabelled Image • Dissolved As was higher in biotic incubations compared with abiotic controls. • As mobilization resulted from the reductive dissolution of amorphous iron minerals. • The released As was partly immobilized in newly formed crystalline iron minerals. • As(V) reduction and release were affected by sulfate-reducing bacterium Desulfocapsa. [ABSTRACT FROM AUTHOR]

Microplastic (MP) has become a concerning global environmental problem. It is toxic to aquatic organisms and can spread through the food chain to ultimately pose a threat to humans. In the environment, MP can interact with microbes and act as a microbial habitat. However, effects of polystyrene MP on the gut microbiota in mammals remain unclear. Here, male mice were exposed to two different sizes of polystyrene MP for 5 weeks to explore its effect. We observed that oral exposure to 1000 μg/L of 0.5 and 50 μm polystyrene MP decreased the body, liver and lipid weights in mice. Mucus secretion in the gut decreased in both sizes of polystyrene MP-treated groups. Regarding the gut microbiota, at the phylum level, polystyrene MP exposure decreased the relative abundances of Firmicutes and α- Proteobacteria in the feces. Furthermore, high throughput sequencing of the V3-V4 region of the 16S rRNA gene revealed significant changes in the richness and diversity of the gut microbiota in the cecums of polystyrene MP-treated mice. At the genus level, a total of 6 and 8 types of bacteria changed in the 0.5 and 50 μm polystyrene MP-treated groups, respectively. Furthermore, an operational taxonomic unit (OTU) analysis identified that 310 and 160 gut microbes were changed in the 0.5 and 50 μm polystyrene MP-treated groups, respectively. In addition, the hepatic triglyceride (TG) and total cholesterol (TCH) levels decreased in both 1000 μg/L 0.5 and 50 μm polystyrene MP-treated groups. Correspondingly, the relative mRNA levels of some key genes related to lipogenesis and TG synthesis decreased in the liver and epididymal fat. These results indicated that polystyrene MP could modify the gut microbiota composition and induce hepatic lipid disorder in mice; while the mouse is a common mammal model, consequently, the health risks of MP to animals should not be ignored. [ABSTRACT FROM AUTHOR]

Abstract Microplastics (MPs), which are new environmental pollutants with a diameter of <5 mm, have received wide attention in recent years. However, there are still very limited data regarding the risks of MPs to animals, especially higher mammals. In this study, we exposed male mice to 5 μm pristine and fluorescent polystyrene MP for six weeks. The results showed that the polystyrene MP was observed in the guts of mice and could reduce the intestinal mucus secretion and cause damage the intestinal barrier function. In addition, high-throughput sequencing of the V3-V4 region of the 16S rRNA gene was used to explore the change of the gut microbiota composition in the cecal content. At the phylum level, the content of Actinobacteria decreased significantly in the polystyrene MP-treated group. The PD whole-tree indexes of the alpha diversity and principal component analysis (PCA) of the beta diversity indicated that the diversity of gut microbiota was altered after polystyrene MP exposure. At the genus level, a total of 15 types of bacteria changed significantly after exposure to polystyrene MP. Furthermore, the predicted KEGG (Kyoto Encyclopedia of Genes and Genomes) metabolic pathway differences indicated that the main metabolic pathways of the functional genes in the microbial community were significantly influenced by the polystyrene MP. In addition, indexes of amino acid metabolism and bile acid metabolism in the serum were analyzed after polystyrene MP exposure. These results indicated that polystyrene MP caused metabolic disorders. In conclusion, the polystyrene MP induced gut microbiota dysbiosis, intestinal barrier dysfunction and metabolic disorders in mice. This study provided more data on the toxicity of MPs in a terrestrial organism to aid in the assessment of the health risks of polystyrene MP to animals. Graphical abstract Unlabelled Image Highlights • 5 μm polystyrene microplastic could be accumulated in the gut of mice. • 5 μm polystyrene microplastic induced intestinal barrier dysfunction in mice. • 5 μm polystyrene microplastic induced gut microbiota dysbiosis in mice. • 5 μm polystyrene microplastic induced bile acids metabolism disorder in mice. [ABSTRACT FROM AUTHOR]

Pollution of Sb(III) in water has caused great concern in recent years. Nanoscale zero-valent iron (nZVI) can detoxify Sb(III) polluted water, but the rapid passivation and low adsorption capacity limit its practical application. Hence, this study provides a new and efficient nanotechnology to remove Sb(III) using the sulfidated nanoscale zero-valent iron (S-nZVI). The S-nZVI exhibits higher Sb(III)-removal efficiency than pristine nZVI under both aerobic and anoxic conditions. The adsorption capacity of Sb(III) by optimized S-nZVI (465.1 mg/g) is 6 times as high as that of the pristine nZVI (83.3 mg/g) under aerobic conditions. The results indicate that Sb(III) and Sb(V) can be immobilized on the surface of S-nZVI by forming Fe-S-Sb precipitates. Moreover, characterization results demonstrate that the existence of S2− can not only activate H 2 O 2 to produce hydroxyl radical, but also accelerate the cycle of Fe3+/Fe2+ to improve the efficiency of Fenton reaction. Therefore, S-nZVI can produce more hydroxyl radicals to oxidize Sb (III) to Sb (V) and results in 2.3-fold higher oxidation rate of Sb(III) compared to pristine nZVI. The formed FeS layer on the S-nZVI surface can also improve the release ability of Fe2+ and accelerate the formation of nZVI corrosion products. S-nZVI thus holds great potential to be applied in antimony removal. Unlabelled Image • The existence of S2− enhanced the oxidation ability of S-nZVI to Sb(III) • The cycle of Fe3+/Fe2+ was accelerated in S-nZVI system • The mechanism of antimony under aerobic or anoxic conditions were investigated [ABSTRACT FROM AUTHOR]

The situation of eutrophication and shortage of phosphorus resources have triggered the development of new methods for the removal and recovery of phosphorus. In this study, a novel and highly efficient composite (nano-CaO 2 /BC) was fabricated by using the porous biochar (BC) to load calcium peroxide (CaO 2) nanoparticles. The developed nano-CaO 2 /BC was applied to remove and recover phosphate from P-contained sewage. The phosphate removal performance of the composite was examined using the bulk solutions with different pH values, coexisting anions, composite dosages, and initial phosphate concentrations. The phosphate adsorption was a typical chemisorption process that agreed well with the pseudo-second-order kinetic model. Isotherm studies showed that the adsorption matched well with Langmuir-Freundlich and the maximum adsorption capacity at equilibrium was 213.22 ± 13.57 mg g−1 (298 K). The characterization results demonstrated that the predominant adsorption mechanism was precipitation. Moreover, the composite had good reusability. The seedling growth test confirmed that the P-laden composite can be mixed with soil to promote the growth of seedlings. Therefore, the method of "cycle back to soil" of used composite provided a way of resource utilization and waste disposal. The CaO 2 suspension was formed firstly, then adding the biochar into it to load CaO 2 nanoparticles, fabricating nano-CaO 2 /BC which can be used to remove phosphate in wastewater. The predominant adsorption mechanism was precipitation. P-laden nano-CaO 2 /BC can be cycled back to soil to promote the growth of seedlings as a P-fertilizer, realizing resource utilization and waste disposal. Unlabelled Image • Nano-CaO 2 /BC is facilely synthesized to efficiently remove phosphate. • Nano-CaO 2 /BC has a good removal ability in wide initial pH and temperature ranges. • P-laden nano-CaO 2 /BC can be cycled to soil to enhance the growth of seedlings. [ABSTRACT FROM AUTHOR]

• Microwave-assisted with CH 3 COONH 4 synthesis meets sustainable requirements. • The PS catalytic performance was enhanced through dual modulation. • The reactive sites of OG was predicted by FMO and DD method. • The electron circulation can be maintained by the battery-likely Fe-MOFs-D. In this study, four typical modulators (NH 4 OH(A), CH 3 COOH(B), CH 3 COONa(C) and CH 3 COONH 4 (D)) were applied to modulate the microwave-assisted synthesis of Fe-MOFs. The effects of various modulators on the yield, electrochemistry activity and PS activation capacity of prepared catalysts were systematically investigated. The ideal modulator was revealed as the 7.5 mM CH 3 COONH 4. Contributed by the defects caused by the dual effects of CH 3 COONH 4 , Fe-MOFs-D-7.5/PS system showed excellent orange G (OG) degradation with high reaction stoichiometric efficiency (RSE) and desirable recycling performance. The main radicals should be SO 4 ·− and O 2 ·− which were confirmed by EPR and chemical quenchers. Furthermore, the frontier molecular orbital (FMO) theory and dual descriptor (DD) method were employed in predicting radical attacking sites of OG. According to the results of theoretical computations and experimental detection, degradation pathways of OG in Fe-MOFs-D-7.5/PS system were proposed. Similar to the function of the battery, this study gives new insight into the possible mediatory roles of Fe-MOFs-D-7.5 in PS activation by transferring the electrons between PS and the unsaturated metal sites (CUS). The Fe-MOFs-D-7.5/PS system is a promising process for environmental remediation. [ABSTRACT FROM AUTHOR]