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Currently, microplastic pollution is more serious and complicates the toxic effects of other co-existing pollutants in the environment. However, the effect and mechanism of biodegradable plastics on the growth and metabolism of probiotic remain unclear. This work selected Bacillus amyloliquefaciens as model bacterium for a three-day exposure experiment to probe the issues. The results showed that 100 mg/L polylactic acid microplastics (PLA MPs) (3–4 mm, flake shape) caused oxidative damage to cell membranes, disrupted cell wall composition and inhibited cell growth by 21.2–27.5 %. The toxicity was not simply additive or synergistic effects when PLA MPs (100 mg/L) and copper ions (10 mg/L) coexisted. PLA MPs did not significantly increase the toxicity of copper to bacteria, instead triggered some mechanisms to resist the toxicity of copper. The bacteria formed spores to resist PLA MPs, while the copper ions toxicity was weaken by chelation and efflux. It is worth noting that copper ions instead increased the expression of genes related fengycin and iturin then improving the bacteriostatic activity of the probiotic. This paper deeply analyzes the toxicity mechanism of combined pollution on Bacillus amyloliquefacien, and also provides new perspective for helping to inhibit pathogenic bacteria under biodegradable microplastics and metal stress. [Display omitted] • Paper discussed the toxicity of biodegradable microplastics and copper on probiotic. • Polylactic acid microplastics still had a certain toxicity to bacteria. • The toxicity of combined pollutants was not simple synergistic or additive effects. • Pollutants might instead improve the bacteriostatic effect of inoculants. [ABSTRACT FROM AUTHOR]

Epidemiological studies suggested that ambient fine particulate matter (PM 2.5 ) exposure was associated with cardiovascular disease. However, the underlying mechanism, especially the mitochondrial damage mechanism, of PM 2.5 -induced heart acute injury is still unclear. In this study, the alterations of mitochondrial morphology and mitochondrial fission/fusion gene expression, oxidative stress, calcium homeostasis and inflammation in hearts of rats exposed to PM 2.5 with different dosages (0.375, 1.5, 6.0 and 24.0 mg/kg body weight) were investigated. The results indicated that the PM 2.5 exposure induced pathological changes and ultra-structural damage in hearts such as mitochondrial swell and cristae disorder. Furthermore, PM 2.5 exposure significantly increased specific mitochondrial fission/fusion gene (Fis1, Mfn1, Mfn2, Drp1 and OPA1) expression in rat hearts. These changes were accompanied by decreases of activities of superoxide dismutase (SOD), Na + K + -ATPase and Ca 2+ -ATPase and increases of levels of malondialdehyde (MDA), inducible nitric oxide synthase (iNOS) and nitric oxide (NO) as well as levels of pro-inflammatory mediators including TNF-α, IL-6 and IL-1β in rat hearts. The results implicate that mitochondrial damage, oxidative stress, cellular homeostasis imbalance and inflammation are potentially important mechanisms for the PM 2.5 -induced heart injury, and may have relations with cardiovascular disease. [ABSTRACT FROM AUTHOR]

Macrophyte rhizospheric dissolved organic matter (ROM) served as widespread abiotic components in aquatic ecosystems, and its effects on antibiotic residues and antibiotic resistance genes (ARGs) could not be ignored. However, specific influencing mechanisms for ROM on the fate of antibiotic residues and expression of ARGs still remained unclear. Herein, laboratory hydroponic experiments for water lettuce (Pistia stratiotes) were carried out to explore mutual interactions among ROM, sulfamethoxazole (SMX), bacterial community, and ARGs expression. Results showed ROM directly affect SMX concentrations through the binding process, while C O and N-H groups were main binding sites for ROM. Dynamic changes of ROM molecular composition diversified the DOM pool due to microbe-mediated oxidoreduction, with enrichment of heteroatoms (N, S, P) and decreased aromaticity. Microbial community analysis showed SMX pressure significantly stimulated the succession of bacterial structure in both bulk water and rhizospheric biofilms. Furthermore, network analysis further confirmed ROM bio-labile compositions as energy sources and electron shuttles directly influenced microbial structure, thereby facilitating proliferation of antibiotic resistant bacteria (Methylotenera, Sphingobium, Az spirillum) and ARGs (sul 1, sul 2, intl 1). This investigation will provide scientific supports for the control of antibiotic residues and corresponding ARGs in aquatic ecosystems. [Display omitted] • Amide and amino groups in ROM are main binding sites for sulfamethoxazole. • ROM bio-labile compositions are closely linked to microbial metabolisms. • ROM fractions favored the formation of rhizospheric biofilms. • SMX pressure stimulated the succession of bacterial community. • Rhizospheric biofilms offered favorable microenvironments for ARB development. [ABSTRACT FROM AUTHOR]

Plastics enter the environment and break up into microplastics (MPs) and even nanoplastics (NPs) by biotic and abiotic weathering. These small particles are widely distributed in the environmental media and extremely mobile and reactive, easily suspending in the air, infiltrating into the soil, and interacting with biota. Current research on MPs/NPs is either in the abiotic or biotic compartments, with little attention paid to the fact that the biosphere as a whole. To better understand the complex and continuous movement of plastics from biological to planetary scales, this review firstly discusses the transport processes and drivers of microplastics in the macroscopic compartment. We then summarize insightfully the uptake pathways of MPs/NPs by different species in the ecological compartment and analyze the internalization mechanisms of NPs in the organism. Finally, we highlight the bioaccumulation potential, biomagnification effects and trophic transfer of MPs/NPs in the food chain. This work is expected to provide a meaningful theoretical body of knowledge for understanding the biogeochemical cycles of plastics. [Display omitted] • The transport of MPs in macroscopic compartments are discussed. • Uptake pathways of MPs/NPs in different biota are summarized. • Different mechanisms of cellular internalization of NPs in organisms are analyzed. • Bioaccumulation potential and biomagnification effects of MPs/NPs are assessed. • Evidence for trophic transfer of MPs/NPs along the food chain is highlighted. [ABSTRACT FROM AUTHOR]

We reported the discovery and identification of emerging sulfur-containing polycyclic aromatic hydrocarbons, namely polycyclic aromatic sulfur heterocycles (PASHs), in PM 2.5 collected from two typical regions of China, Taiyuan and Guangzhou. Until now, there is no research on contamination status, sources and potential health risks of this unexpected group of organic contaminants in PM 2.5. High atmospheric concentrations (ng m−3) and significant time-dependent variations were determined in PM 2.5 of Taiyuan from 2017 to 2018. Coal combustion/secondary formation and traffic emission/secondary formation were apportioned as possible pollution sources for the PM 2.5 -bound PASHs in Taiyuan and Guangzhou, respectively. Dithiothreitol and cell viability assays were applied for evaluations of PASH-induced reactive oxygen species (ROS) production and cell toxicity based on the determined real exposure levels for adults. The results illustrated that PASHs in PM 2.5 possibly caused oxidative stress and inhibition of human bronchial epithelial cells in seriously polluted regions such as Taiyuan, suggesting that the pollutant-induced health concerns may need more investigations. This study provides new insights into PM 2.5 pollution, and is beneficial for the development of effective contamination control strategies and reduction of risks on public health. [Display omitted] • Detailed contamination levels of PM 2.5 -bound PASHs were firstly studied. • Different pollution sources were identified in Taiyuan and Guangzhou. • The PM 2.5 -bound PASHs possessed potential health risks for human inhalation. [ABSTRACT FROM AUTHOR]

Stabilization is the most important remediation mechanisms for sediment polluted heavy metals. However, little research has been done on the identification of microenvironmental response and internal correlation, as well as synergistic mechanisms during heavy metal remediation. This study aims to investigate the inner response mechanisms of microenvironment after the lead (Pb) are gradually stabilized in sediment. An eco-friendly amendment strategy which firstly used 100% biodegradable sophorolipids (SOP) to modify chlorapatite (ClAP) for the fabrication of SOP@nClAP was applied in this study. The stabilization efficiency of Pb was significantly improved by SOP@nClAP compared with ClAP. Most importantly, the high-throughput sequencing showed that the dominant species in the sediment changed with the stabilization of Pb. The decrease of Proteobacteria and increase of Firmicutes , especially the Sedimentibacter within the phylum Firmicute directly suggested that large amounts of Pb were stabilized. This research is not only devoted to stabilize Pb in sediment by eco-friendly amendment strategy, but also keep a watchful eye on microenvironment response mechanisms during the Pb stabilization in sediment. Therefore, this study lays a foundation for the future application of more heavy metal amendment strategies in the sediment environment and improves the possibility of large-scale site amendment. [Display omitted] • An eco-friendly sophorolipids modified chlorapatite (SOP@nClAP) was fabricated. • Pb was significantly stabilized in sediment by SOP@nClAP. • Response of microenvironment was also beneficial to remediation of sediment. • SOP can greatly improve the effective utilization of phosphorus in ClAP. [ABSTRACT FROM AUTHOR]

Industrial progress has brought us an important polymer material, i.e. plastic. Because of mass production and use, and improper management and disposal, plastic pollution has become one of the most pivotal environmental issues in the world today. However, the current researches on microplastics/nanoplastics are mainly focused on individual aquatic, terrestrial and atmospheric environments, ignoring the fact that the natural environment is a whole. In this regard, the transport of microplastics/nanoplastics among the three environment compartments, including reciprocal contributions and inherent connections, and the impact of microplastics/nanoplastics on organisms living in multiple environments are research problems that we pay special attention to. Furthermore, this paper comprehensively reviews the transport and distribution of microplastics/nanoplastics in individual compartments and the toxicity of organisms, either alone or in combination with other pollutants. The properties of microplastics/nanoplastics, environment condition and the growth habit of organisms are critical to the transport, distribution and toxicity of microplastics/nanoplastics. These knowledge gaps need to be addressed urgently to improve cognition of the degree of plastic pollution and enhance our ability to deal with pollution. Meanwhile, it is hoped that the paper can provide a relatively complete theoretical knowledge system and multiple "leads" for future innovative ideas in this field. ga1 • Discuss the interface transport of microplastics/nanoplastics (MPs/NPs) among three major environment compartments. • Analyze the effects of MPs/NPs to creatures that need to span aquatic, terrestrial and atmospheric environment. • Completely review the transport pathway and toxicity of MPs/NPs in individual environments. [ABSTRACT FROM AUTHOR]