Environmental reservoirs of antibiotic resistance (AR) are a growing concern that are gathering more attention as potential sources for human infection. Carbapenem-resistant Enterobacteriaceae (CRE) are extremely dangerous, as carbapenems are often drugs of last resort that are used to treat multi-drug resistant infections. Among the genes capable of conferring carbapenem resistance to bacteria, the most transferrable are those that produce carbapenemase, an enzyme that hydrolyzes carbapenems and other β-lactam antibiotics. The goal of this review was to comprehensively identify global environmental reservoirs of carbapenemase-producing genes, as well as identify potential routes of transmission to humans. The genes of interest were Klebsiella pneumoniae carbapenemase (KPC), New Delhi Metallo-β-lactamase (NDM), Oxacillinase-48-type carbapenemases (OXA-48), and Verona Integron-Mediated Metallo-β-lactamase (VIM). Carbapenemase genes have been reported in the environment on almost every continent. Hospital and municipal wastewater, drinking water, natural waterways, sediments, recreational waters, companion animals, wildlife, agricultural environments, food animals, and retail food products were identified as current reservoirs of carbapenemase-producing bacteria and genes. Humans have been recorded as carrying CRE, without recent admittance to a hospital or long-term care facility in France, Egypt, and China. CRE infections from the environment have been reported in patients in Montpellier, France and Cairo, Egypt. This review demonstrates the need for 1) comprehensive monitoring of AR not only in waterways, but also other types of environmental matrices, such as aerosol, dusts, periphyton, and surfaces in indoor environments; and 2) action to reduce the prevalence and mitigate the effects of these potentially deadly resistance genes. In order to develop an accurate quantitative model for environmental dimensions of AR, longitudinal sampling and quantification of AR genes and bacteria are needed, using a One Health approach.

The environmental consequences of nano-CuO particles have gained significant attention in recent decades. Identification of the mechanisms for soil and plant responses with respect to the chemical speciation of nano-CuO (mainly the exchangeable and reducible fractions) remains scarce. Here, we analyzed different chemical speciation of Cu and DTPA-extractable Cu over 42 days in (1) control soil without Cu addition; (2) soil treated with nano-CuO particles; and (3) soil treated with CuSO₄ solution. The applied dose was 500 mg Cu kg⁻¹ and maize was grown in these soils. Plant growth was inhibited, but the inhibition by nano-CuO was slightly weaker compared to CuSO₄. Cu accumulations were similar in the roots for CuSO₄ and nano-CuO treatments, but significantly higher in the shoots for CuSO₄ treatment. This indicates that Cu from nano-CuO-treated soils mainly accumulated in roots but rarely transferred to shoots. Enzyme activities on the rhizoplane visualized by zymography were strongly depressed by CuSO₄ but slightly inhibited by nano-CuO. Microbial community diversity measured by 16S rRNA was the lowest in CuSO₄-treated soils among three treatments. These results were explained by the following mechanisms: (1) Gradual increases of DTPA-extractable and exchangeable Cu were found in nano-CuO-treated soil, and the final concentrations at day 42 were only half of those in CuSO₄-treated soil; (2) Enzyme activities on the rhizoplane were positively related to soil pH and negatively correlated with DTPA-extractable and exchangeable Cu; (3) Even though reducible Cu in nano-CuO-treated soils was 1.3 times higher than in CuSO₄-treated soils, indicating stronger nano-accrued oxidative stress in nano-CuO-treated soils, the toxicity induced by nano-CuO particles was still weaker than CuSO₄. Nevertheless, the toxicity of Cu particles to plants and microbes mainly depends on the gradually-released bioavailable Cu. This demonstrates the greater importance of bioavailable Cu concentrations for toxicity modulation rather than the scale of Cu particles.

Microplastic particles are a global concern due to their widespread and growing threat to marine and coastal environments. To improve knowledge of microplastic pollution in China, we investigated 25 sediment samples collected with a box corer in the Southern Yellow Sea and East China Sea off the coast of China. The microplastics were extracted from sediments via density separation, after which they were observed under a microscope and characterized according to shape, color, and size, while polymer type identification was performed using micro-Fourier transform infrared spectroscopy. The abundance of microplastics in the offshore region of the Southern Yellow Sea and East China Sea was mapped. The mean concentration of microplastics at the 25 sites was 13.4 ± 0.6 particles 100 g⁻¹ dry weight (range: 6.0–24.0 particles 100 g⁻¹ dry weight). Based on the categorization according to shape, color, and size, fiber (77%) was the most abundant shape, while blue (35%) and transparent (29%) were the most prevalent colors. In addition, the dominant size of microplastics was smaller than 1000 μm which accounted for 89%. Finally, polyethylene, polyethylene terephthalate, acrylic, polyester, cellulose, and cellophane were the most abundant types of microplastics identified. Our result highlighted the presence of microplastics in offshore sediments from the Yellow Sea and East China Sea, and provided useful information for evaluating the environmental risks posed by microplastics in China.

Plastic pollution is continuously growing on a global scale and emerging as a major environmental hazard. Smaller-sized plastics, so-called microplastics (<5 mm), are considered as being omnipresent throughout the aquatic environment, yet freshwater ecosystems have received little attention so far and are still largely unstudied. Present study aims to expand the current knowledge on microplastics in freshwater systems by documenting the occurrence in the digestive system of fish from 15 rivers at 17 locations in Flanders, Belgium. To increase inter-study comparability and identification accuracy, a more standardized protocol was combined with a conservative approach towards acceptance of microplastic particles. Four rivers were found to have fish containing microplastics. However, no significant differences could be established between the sampling sites. In total 78 specimens of gudgeon (Gobio gobio) have been investigated, 9% of which had ingested at least one microplastic item, thus showing that contamination appears to be limited. Microscopic and spectroscopic analysis showed the microplastics to be from various sources with a diverse range of physical characteristics. Out of the eight items identified as microplastics, seven different polymer types were identified. Although further detailed research is necessary, this preliminary study shows that gudgeons from several Flemish rivers are contaminated with microplastics.

Phthalate esters (PAEs), as widely used plasticizers, have been concerned for their possible disruption of estrogen functions via binding to and activating the transcription of estrogen receptors (ERs). Nevertheless, the computational interpretation of the mechanism of ERs activities modulated by PAEs at the molecular level is still insufficient, which hinders the reliable screening of the ERs-active PAEs with high speed and high throughput. To bridge the gap, the in silico simulations considering the effects of coactivators were accomplished to explore the molecular mechanism of action for the purpose of predicting the estrogenic potencies of PAEs. The transcriptional activation functions of human ERα (hERα) modulated by PAEs is predicted via the simulations including binding interaction of PAEs and hERα, conformational changes of PAEs-hERα complexes and recruitment of coactivators. Molecular insight into the diverse estrogen mechanism of action among PAEs with regard to hERα agonists and selective estrogen receptor modulators (SERMs) is provided. Agonist-modulated conformational change of hERα leads to the optimal exposure of its Activation Function 2 (AF-2) surface which, in turn, facilitates the recruitment of coactivators, therefore promoting the transcriptional activation functions of hERα. Conversely, binding interaction of hERα with SERMs among PAEs leads to the conformational change with blocked AF-2 surface, thus preventing the recruitment of coactivators and consequently inhibiting the AF-2 activity. The two-hybrid recombinant yeast is experimentally used for verification. The established in silico evaluation methodology exhibits great promise to speed up the prediction of chemicals which work as hERα agonist or SERMs.

Solid wastes containing potentially toxic elements (PTEs) are widely generated around the globe. Critical concerns have been raised over their impacts on human health and the environment, especially for the exposure to PTEs during the transfer and disposal of the wastes. It is important to devise highly-efficient and cost-effective treatment technologies for the removal or immobilisation of PTEs in solid wastes. However, there is an inadequate overview of the global flow of PTEs-contaminated solid wastes in terms of geographical distribution patterns, which is vital information for decision making in sustainable waste management. Moreover, in view of the scarcity of resources and the call for a circular economy, there is a pressing need to recover materials (e.g., precious metals and rare earth elements) from waste streams and this is a more sustainable and environmentally friendly practice compared with ore mining. Therefore, this article aims to give a thorough overview to the global flow of PTEs and the recovery of waste materials. This review first summarises PTEs content in various types of solid wastes; then, toxic metal(loid)s, radioactive elements, and rare earth elements are critically reviewed, with respect to their patterns of transport transformation and risks in the changing environment. Different treatments for the management of these contaminated solid wastes are discussed. Based on an improved understanding of the dynamics of metal(loid) fates and a review of existing management options, new scientific insights are provided for future research in the development of high-performance and sustainable treatment technologies for PTEs in solid wastes.

The removal of arsenic from groundwater is an important issue for environmental safety and human health. Research focused on the comparative assessment of arsenic removal from arsenic-bearing groundwater and arsenic-containing-synthetic water (2 mg/L) using natural magnetic material (NMM) (rock) and synthesized magnetic material (SMM) by Bacillus pasteurii and humic acid. The arsenic-bearing groundwater (97.56 ± 0.05 μg/L) exceed the WHO limit (10 μg/L) of arsenic concentration for drinking water. The NMM contains dominantly magnetite, hematite, ferrihydrate, coesite, quartz, and stishovite. The NMM of natural rock exhibited the existence of iron (6.25–8.86% Fe₃O₄), which is widespread and important component in sedimentary rocks. The investigation on vibrating sample magnetometers (VSM) of NMM and SMM demonstrated the typical magnetization properties, which can be separated after arsenic removal process. The thermogravimetric analysis (TGA) of SMM displayed the existence of organic matter decomposition during particle synthesis. The TEM and SEM exhibited the nanoparticle particle formation within the range of 10–39 nm (10–20 nm particle Fe₃O₄ through B. pasteurii). FTIR spectrum (before and after removal of arsenic) indicated the existence and binding nature in between arsenic and iron. >90% of arsenic was removed from arsenic-bearing groundwater using Fe₃O₄, Fe₃O₄ (N₂-Environment), Fe₃O₄ with humic acid, and Fe₃O₄ with B. pasteurii after 25 min, 8 min, 13 min and 120 min, respectively. In case of NMM in Site-A, the arsenic removal was observed very fast as 85–87% within 30 s, whereas 95–99%, 93–95% and 88–91% removal detected using the sample of Site-A, Site-B, and Site-C respectively, after 120 min at natural pH (8.31 ± 0.05) of arsenic-bearing groundwater. Thus, NMM, (ecofriendly green material), can be applicable for arsenic removal from arsenic-bearing groundwater.

This study evaluated hormetic effect of oxidative stress exerted by fullerene crystals (nC₆₀) on Daphnia pulex, employing transcriptomics and metabolomics. D. pulex were exposed to various concentrations of nC₆₀ for 21 days. Hormetic effect of oxidative stress was most evident after 7 days, with markedly increased L-Glutathione (GSH) concentration and Superoxide Dismutase (SOD) activity at low doses of nC₆₀ exposure, and oppositely at high doses. The transcriptomics and metabolomics were used to elucidate the molecular mechanism underlying the hormesis in oxidative stress. There were significant alterations in major pathways involving oxidative stress and energy metabolism in D. pulex. Some important intermediates and the expression of their regulatory genes coincided with each other with first up-regulated and then down-regulated with the concentration increased, consistent with the hormesis description. The nC₆₀ interfered the TCA cycle of D. pulex. The synthesis of L-cysteine and glutamate was directly affected, and further disturbed the synthesis of GSH. This work is of great significance to provide the molecular-level evidence into the hormetic effect in oxidative stress of D. pulex exposed to nC₆₀.

Degrading aquatic organic pollutants efficiently is very important but strongly relied on the design of photocatalysts. Porous graphene could increase photocatalytic performance of ZnO nanoparticles by promoting the effective charge separation of electron-hole pairs if they can be composited. Herein, porous graphene, ZnO nanoparticles and porous graphene/ZnO nanocomposite were prepared by fine tuning of partial combustion, which graphene oxide imperfectly covered by the layered Zn salt was combusted under muffle furnace within few minutes. Resulting ZnO nanoparticles (32–72 nm) are dispersed uniformly on the surface of graphene sheets, the pore sizes of porous graphene are in the range from ∼3 to ∼52 nm. The synthesized porous graphene/ZnO nanocomposite was confirmed to show enhanced efficiency under natural sunlight irradiation compared with pure ZnO nanoparticles. Using porous graphene/ZnO nanocomposite, 100% degradation of methyl orange can be achieved within 150 min. The synergetic effect of photocatalysis and adsorption is main reason for excellent MO degradation of PG/ZnO nanocomposite. This work may offer a new route to accurately prepare porous graphene-based nanocomposite and open a door of their applications.

We assessed factory-calibrated field-portable X-ray fluorescence (pXRF) data quality for use with minimally-prepared aquatic sediments, including the precision of replicate pXRF measurements, accuracy of factory-calibrated pXRF values as compared to total digestion/ICP-OES concentrations, and comparability of calibrated pXRF values to extractable concentrations. Data quality levels for precision, accuracy, and comparability were not equivalent for element/analyzer combinations. All analyses of elements that were assessed for precision and accuracy on a single analyzer were both precise (<10% relative standard deviation) and accurate (r2 > 0.85) for K, Ca, Ti, Mn, Fe, and Zn. Calibrated pXRF values for Al, K, Ca, Ti, Mn, Fe, Cu, Zn, and Pb were within ∼10% relative difference of total digestion/ICP-OES concentrations. Calibrated pXRF values for Fe, Cu, Zn, As, and Pb were within ∼20% relative difference of extractable concentrations. Some elements had a higher level of data quality using specific analyzers, but in general, no pXRF analyzer had the highest level of data quality in all categories. Collectively, our data indicate that a wide range of factory-calibrated pXRF units are capable of providing high-quality total concentrations for the analysis of aquatic sediments.