Search

Residues of antibiotics in the soil can have adverse effects on crop plants related closely to humans. However, there is a lack of knowledge on the phytotoxicity of antibiotics to sensitive species. The aim of our study was mainly to reveal tetracycline stress on the mobilization of seed storage proteins, lipids, and minerals of Chinese cabbage (Brassica rapa L.) during radicle elongation after germination. The Chinese cabbage seed was incubated for 48 h in tetracycline solutions at 1 and 5 μM. For the cotyledons of the seed, the result of TEM showed that tetracycline significantly hindered the mobilization of protein bodies, which was in line with the result of FTIR spectroscopy. However, the mobilization of oil bodies and mineral bodies in cotyledons was not significantly disturbed by the stress of tetracycline, as well as the energy supply in different organs including the cotyledons, hypocotyl, and radicle of the seed. To our knowledge, this is the first study to demonstrate the disturbance on mobilization of protein bodies in seed storage reserves caused by the stress of tetracycline at low levels during radicle elongation after germination.

Resources and the environment are two eternal themes of social development. Nuclear energy, a green source with high energy density, can greatly alleviate the pressure of the energy crisis in today's society. To guarantee the long-term sufficient supply of nuclear fuel, mining seawater uranium is imperative. Meanwhile, the great threats of uranium to ecological security and human health make the removal of uranium from the environment urgent. To achieve these ends, a large number of materials with specific functions have been born as a result. Among them, amidoxime-based materials serve as one of the most promising candidates and are the main tool used for uranium extraction from aqueous systems owing to their special affinity for uranium. However, there is still huge room for improvement in amidoxime-based materials in terms of their economic efficiency and performance. In this paper, we provide a comprehensive review of amidoxime-based materials for uranium recovery and removal, including synthesis strategies, characterization and types of amidoxime-based materials, the factors that influence uranium extraction, and the binding mechanisms between amidoxime ligands and uranyl ions, as well as the cost drivers in applications. Meanwhile, the shortcomings of current research as well as future development directions and research hotspots are also pointed out. Based on the in-depth analysis of the currently available literature, a demand-oriented strategy for fabricating a new generation of amidoxime-based adsorbents was proposed, and means to enhance the adsorbent performance were discussed with regards to four aspects, including adsorption capacity, selectivity, kinetics and regenerability. This paper aims to provide guidance for the purposeful design of novel amidoxime-based materials, and to provide advice on circumventing unfavorable factors and solving the technical problems relating to uranium recovery and removal.

Proton-binding study of humic acid (HA) is critical for describing and modeling the binding mechanism of HA with heavy metals. However, little is known about the intrinsic relationship between protonation behavior and HA characteristics, especially in sediments. In this study, HA was extracted from sediments and combination of spectrographic titration with parallel factor analysis, Gaussian fitting model and two-dimensional correlation spectroscopy analysis was developed as a novel in-situ tool. Results indicated that the intensity changes of fluorophores of sediment HA might be dependent on the structure characteristics (fused or non-fused ring) of phenolic species in the protonation process. Compared with phenolic groups (A1, 5.27 ± 0.05 eV; A3, 3.91 ± 0.02 eV), the carboxyl groups (A2, 4.65 ± 0.03 eV) exhibited greater contribution in the response of chromophores to the protonation process of sediment HA. Furthermore, proton binding to sediment HA first occurred in carboxyl groups and then in phenolic groups. The combined technique is a promising approach for the examination of the binding sites, binding capacities, and binding order in proton-HA binding process under environmental concentrations. Importantly, this method is a sensitive, effective and non-destructive technique without any need pre-concentrate.

Biological tests with plant seeds have been adopted in many studies to investigate the phytotoxicity of pollutants to facilitate the control of risks and remain to be optimized. In this work, the experiment with a small sample size (Experiment 1) and the experiment with a large one (Experiment 2) were designed to study the effect of tetracycline (TC) on Chinese cabbage (Brassica rapa L.) at seed germination and radicle elongation stages. At the former stage, germination number data were obtained to analyze the germination energy (GE) and to judge the probability of the number of germinated seeds (Pn) by the binomial distribution model in Experiment 1. While germination time-to-number data were obtained to analyze the mean time to germination (MGT), the estimate of mean time to germination (EMGT) by survival analysis method, the time to germination for 50% of total seeds (T50) and the germination rate (GR) besides GE in Experiment 2. At the latter stage, the data of radicle length (RL) were obtained in all the experiments and the influence from the former stage on this stage was excluded in Experiment 2 but not in Experiment 1. Results showed that TC had universal adverse effects on the latter stage but not on the former stage in the experiments. Considering the availability of germination data for statistical analysis and the robustness of RL data, the methods adopted in Experiment 2 were more feasible than those in Experiment 1. In addition, Chinese cabbage seeds with medium size have the character of rapid germination compared with the commonly used crop species and can be used to shorten the experimental cycle to study the responses of seeds to pollutants to evaluate the phytotoxicity. We introduced survival analysis method to analyze the germination time-to-number data obtained in seed germination test to evaluate the phytotoxicity of tetracycline.

Capacitive deionization (CDI) has attracted increasing attention over the past decade for the facile removal of ions from aqueous solutions. Nowadays, CDI is rapidly growing and evolving, and has been applied in many aspects. One important application field is water remediation, i.e., removing ionic contaminants of concern from water. Herein, we investigated the feasibility of perchlorate removal from brackish waters by batch-mode CDI technology. Effects of various operating parameters on dynamic electrosorption processes of both perchlorate and chloride were examined. Meanwhile, a one-dimensional CDI process model for dual-anions was developed to quantitatively describe the electrosorption kinetics of perchlorate and chloride, and an excellent agreement between the modeling results and the experimental data was observed. Experimental results revealed a favorably strong preferential adsorption of ClO4− over Cl− in the studied CDI system under various conditions. Moreover, only slight discrepancy between adsorption-desorption cycles was found, demonstrating the good regeneration of electrodes and operational stability of the CDI cell. Finally, the scale-up studies indicated that the CDI stack with multiple pairs of electrodes could achieve a much more superior ion removal performance than the CDI cell with only one pair of electrodes. To conclude, these results showed that the CDI system was effective for perchlorate selective removal in the presence of other major ions and had potential in treatment of perchlorate-contaminated brackish water.

Nanoplastics and carbon nanotubes (CNTs) is one of the emerging environmental contaminants and a widely used engineering nanomaterial, and their biological toxicity has been frequently studied. However, there has been no research on the combined exposure of these two totally different shape nanoparticles. To explore their potential threat to freshwater ecosystems, Microcystis aeruginosa (M. aeruginosa) was exposed to concentration gradients of polystyrene nanoplastics (Nano-PS) and multi-walled carbon nanotubes (MWCNTs). The physiological analysis and whole-transcriptome sequencing were integrated to certify the cytotoxicity. As the physiological results showed, the low concentration (5 mg/L) of these two nanoparticles showed a stimulation on the growth (6.49%–12.2%) and photosynthesis (0–7.6%), and the coexposure was slightly higher than individuals. However, other concentrations showed inhibitory effect, especially at high concentration (50 mg/L), and all physical signs and electron microscope images showed obvious cytotoxicity. Compared with the individuals, the coexposure showed an antagonistic effect induced by the heterogeneous agglomeration which decreased the surface toxicity and the contact with algae of nanomaterials. Transcriptome results showed that coexposure treatment had the fewest differential genes, and the primary effects embodied in the disturbances of cellular and metabolic processes which were superior to the individuals. In the 50 mg/L Nano-PS, the translation process was significantly disordered, and MWCNTs could disrupted the photosynthesis, multiple metabolism processes, membrane transport, and translation. These findings demonstrated the aquatic toxic mechanism from cellular and metabolic processes of Nano-PS and MWCNTs for M. aeruginosa and provided valuable data for environmental risk assessment of them.

Tetracycline (TC), a widely used antibiotic, is easy to enter the aquatic ecosystem through soil erosion, livestock manure and wastewater discharge, resulting in a series of risks. The application of Z-scheme photocatalysts with efficient interface charge separation and transfer has been regard as an effective strategy for antibiotic degradation. Herein, a novel ternary Z-scheme Bi12O17Cl2/Ag/AgFeO2 was successfully synthesized by ultrasound-assisted ethanol reduction of Ag+ on the interface of Bi12O17Cl2 and AgFeO2. The Bi12O17Cl2/Ag/AgFeO2 Z-scheme system exhibited an enhanced photocatalytic degradation capability for TC, which was over 6.5 times and 2.4 times higher than those of AgFeO2 and Bi12O17Cl2/AgFeO2 system, respectively. The photocatalytic process of TC was explored, and the results indicated that an optimum catalyst concentration of 0.5 g L−1 and a primeval pH (without adjustment) favored the degradation process, while the introduction of exogenous anions (CO32−, SO42− and NO3−) and organic matter (HA) supressed the degradation of TC. Simultaneously, the possible pathway for the degradation process of TC was presented based on the liquid chromatography-mass spectrometry (LC-MS) analysis. Active species trapping experiments and ESR spectra revealed the significant contribution of O2− in the TC degradation, and verified the Z-scheme mechanism of the Bi12O17Cl2/Ag/AgFeO2 system.

Climate change, regarded as one of the major threats to biodiversity and ecosystems, can impact on the distribution and survival of migratory birds. To investigate the threats of climate change to threatened migratory bird distributions, we used species distribution model (SDM) and climatic data under current and future climate scenarios to predict future changes in species distributions and how the geographic distribution of these threatened birds may respond to climate change by 2050. Our results show the hotspots for all species may remain in the lower and middle reaches of the Yangtze River, while more species may dwell in the coastal regions of the Bohai Gulf and the Yellow Sea in the future. Our findings show that the percentage of all species distributions or hotspots for all threatened species covered by national nature reserves (NNRs) in China remain low by 2050. Thus, we propose that China should increase and expand reserves in eastern China. Significantly, we emphasize the creation of protected areas to make it the Ramsar sites in the world and recommend that China should (1) strengthen the cooperation with neighboring countries to share maximum species occurrence data (especially the threatened species), (2) overlay maps of individual species for each taxon to assess the efficiency of coastal nature reserves and predict the hotspots shift under climate change, (3) trade off urban development and ecosystem stability to create new and dynamic protected areas to make it the Ramsar sites, (4) appeal for long-term protection of ecosystem stability to achieve sustainable development in the world.

Herein, we demonstrated the suitability and effectiveness of utilizing flow-electrode capacitive deionization (FCDI) for treatment of fluoride-contaminated brackish groundwater. By comparing operational modes of short-circuited closed-cycle (SCC), isolated closed-cycle (ICC) and single cycle (SC), it was found that SCC mode was the most advantageous. In SCC configuration, the effects of different parameters on the removal of F− and Cl− were investigated including current density, hydraulic residence time (HRT), activated carbon (AC) loading and feed concentration of coexisting NaCl. Results indicated that the steady-state effluent Cl− concentration dropped with elevated applied current, and the decreasing rate got faster with the increase of HRT or AC loading. However, for the steady-state effluent F− concentration, it dropped to a value under a small applied current and maintained stable in spite of the increase in applied current, and both HRT and AC loading had insignificant effects on the steady-state effluent F− concentration. F− was preferentially removed from the treated water compared with Cl−, and a higher ion selectivity could be obtained at lower applied current and smaller HRT with the trade-off being that operation under these circumstances would generate outlet water with little change in conductivity compared to the influent. The removal efficiencies of F− and Cl− both decreased with increasing feed concentration of coexisting NaCl. This study should be of value in establishing FCDI as a viable technology for treatment of fluoride-contaminated brackish groundwater.

Flow-electrode capacitive deionization (FCDI) is attracting growing attention owing to its advantages such as effective ion removal capacity and easy management of the electrodes. Optimization of the flow-electrode comprising carbon materials and aqueous electrolyte is always a research hotspot aimed at improving FCDI performance. Herein, we innovatively introduced appropriate amount of KI3 into the cathodic flow-electrode to provide a highly efficient means of enhancing FCDI desalination performance with a stable behavior in salt electrosorption and desorption over multi-cycle consecutive runs. The accelerated salt removal rate originated from the reversible redox reaction of I3−/I− and the maintenance of the electro-neutrality of the global electrolyte. Although possible minor release or leakage of I−/I3− through the cation-exchange membrane and into the treated water occurred, which makes the proposed approach not quite suitable for potable water production, we demonstrated that this system has great application prospects in treatment of iodide-containing saline wastewater without causing secondary pollution.

Climate changes are related to the changes in the distribution of migratory species, which irreparably harm biodiversity. In this study, we evaluated the habitat change and population centroid shift for 7 orders and 23 different species on the IUCN (International Union for the Conservation of Nature and Natural Resources) Red List of migratory birds from 2014 to 2017 in current to mid-21st (2041–2700) century by Maximum Entropy method (MaxEnt) model. We found that there is significant spatial variability in geographical suitability, with the Yangtze River basin losing 9.74% of suitable habitat and the Pearl River basin losing 13% of habitat. The area of suitable habitat decreases over 3% of total habitat area in China under the RCP 2.6, and decreases about 10% of total habitat area in China under RCP 8.5 scenario, with the population centroid of habitat moving about 50 km to northeast on average. Furthermore, the mean suitability of migratory birds will decrease over 3% in the future, which means environmental variables are changing in directions that are not suitable for birds. Migratory birds will change their habitat and growth cycle in response to the climate change. The direction and distance of the population centroid are different for every species. Most of the individual species in the study will move over 50 km and all the species will move to places with higher suitability. For the whole of China, the constraint for migratory birds is t min (Minimum temperature). The dominant variable in southeast China is NDVI (Normalized Difference Vegetation Index), while alt (altitude) in the north China. The decline in the suitable habitat area and shift in the population centroid will lead to the changes in the time and distance of the migration process, resulting in more adverse conditions for the survival of migratory birds. Our study proves the adverse role of climate change in species distribution which is a prerequisite for protecting species in the future.

Stresses of antibiotics can cause strains (i.e. effects) on seed at germination and post-germination stages. But there is a lack of research on the period and type of the effects at present. In this study, Chinese cabbage (Brassica rapa L.), a commonly used crop, was selected to investigate the effect of tetracycline (TC), a major-use antibiotic, on its seed during different periods of the stages. Results showed that there were no significant differences among the germination energy (GE) of control (CK) and treatments, but radicle length (RL) of the treatments, the exposure to TC at post-germination stage (i.e. radicle elongation stage), was all significantly less than that of CK. The initial stage of radicle elongation was the earliest and most sensitive period at which the stress of TC caused the plastic effect on seed. Moreover, the action of TC stress on seed did not have a delayed characteristic. The result of RL was identical to the leakage of intracellular substances at radicle fast elongation stage, but not the Evan’s blue trapped by radicle. We concluded that TC inhibited the elongation of radicle through weakening the cellular metabolic activity rather than leading to the loss of cellular membrane integrity. It should be paid more attention to the phytotoxicity of TC in the field due to its active characteristics revealed in our study.

Climate change and eutrophication are both critical environmental issues currently. Climate change induces more critical microplastic pollution and sediment resuspension in eutrophic lakes, and conversely the presence of microplastics and resuspension events would intensify these two environmental effects. Via evaluating the impacts of microplastics and sediment resuspension on climate change and eutrophication, it is favorable to provide recommendations for ecological protection and policy formulation in regard to the nutrient input as well as the production and utilization of plastic. In this review, we explore how climate change and eutrophication interact with microplastic pollution and sediment resuspension in shallow lakes, highlighting that both of the latter two play a significant role in the former two. Furthermore, future prospects are put forward on the further and deeper research on the global warming and eutrophication in shallow lakes with microplastic pollution.

Antibiotics can induce adverse effects on plants. Brassica crop seeds, for their advantages, are used widely in seed germination test to investigate phytotoxicity of substances. However, their performances on evaluating antibiotics remain to be studied to select sensitive species for control of potential risks. In this work, common species of Chinese cabbage (Brassica rapa L.), edible rape (Brassica napus L.), and cabbage (Brassica oleracea L.) with three cultivars each were selected to compare and analyze the sensitivity difference of their seeds to tetracycline (TC) stress. Results showed that the ratio of axis to cotyledon (RAC) by fresh weight was an alternative endpoint besides radicle length (RL) in the test. The species sensitivity distribution (SSD) based on the effective concentrations causing x% inhibition (ECx) in RL of seeds exposed to TC was applied to compare the sensitivity of seeds and estimate the hazardous concentration for x% species (HCx). From the species-dependent sensitivity and the sensitivity difference of cultivars in the same species of seeds to TC, the performance of Chinese cabbage was the best in the study. The sensitivity of seeds to TC could be evaluated by EC20 related to seed physical traits and germination indices, while the extent of seeds affected by TC could be evaluated by EC50 related to the composition of seed storage reserves. We recommended that it was a new idea to analyze responses of different seeds to TC at large scale according to seed innate characteristics.

High levels of zinc ion (Zn2+) in environmental scenarios have long been considered to be harmful, and this study was experimentally and theoretically performed to explore the feasibility of electro-assisted adsorption of Zn2+ on activated carbon cloth from aqueous solutions in batch-flow mode. The characteristics of carbon cloth were systematically evaluated using cyclic voltammetry and various surface characterization techniques. Effects of operating parameters, including charging voltage, feed Zn2+ concentration, solution volume, and flow rate, on the dynamic removal process of Zn2+ were examined. Meanwhile, a theoretical model was developed to quantitatively describe the electro-assisted adsorption of Zn2+, and an excellent agreement between the modeling results and the experimental data was observed. The Zn2+ removal mechanisms involve both nonelectrostatic interactions (physi- or chemisorption) and electrostatic interactions. Experimental and theoretical results demonstrated a significant enhancemen...

It remains debatable whether carbonized straw reapplying is a better solution than direct straw reapplying. Comparison of the characteristics and complexation behaviors of dissolved organic matter (DOM) derived from straw (ST) and biochar (BC) may offer new insights, but little current information exists. Herein, DOM samples were characterized by Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), revealing that the molecular weight and condensed aromatic components of BCDOM (457.70 Da and 71.16%, respectively) were higher than those of STDOM (433.48 Da and 3.13%, respectively). In particular, the N-containing compounds of BCDOM was more aromatic than STDOM. By combining spectroscopic techniques, complexation modeling, and chemometric analysis, BCDOM was shown to exhibit higher binding parameters (log KM) and more binding sites for Pb than STDOM. Noteworthily, the two binding sites, aromatic N O and aromatic NO2, existed only in the interaction of BCDOM with Pb. Furthermore, while phenol-OH displayed the fastest response to Pb in both STDOM and BCDOM, the binding sequences were not exactly the same. These differences may be related to the variations in the aromaticity and N-containing structures of DOM detected by FTICR-MS. These findings have implications on the stewardship of straw- and biochar-amended soil.

Flow-electrode capacitive deionization (FCDI) has attracted growing attention due to its superior desalination capacity and continuous operation. This study, for the first time, systematically investigated the desalination behaviors of FCDI under a variety of operational modes and made a detailed comparison of relevant operation to provide useful information for selecting appropriate FCDI operational mode. Five operational modes with respect to the flow of electrodes and feed water were studied with both constant voltage and constant current applied. Results revealed that the effluent conductivity during charging decreased continuously in batch mode while decreased quickly and then leveled off in single-pass mode. pH of flow-electrodes fluctuated differently for the operational modes of isolated closed-cycle (ICC), short-circuited closed-cycle (SCC) and open cycle (OC), while pH of the effluent stream maintained stable for all operational modes. The variation of current or voltage could be explained by the change in the resistance of FCDI mainly induced by the middle-chamber salt concentration. Based on the three performance indicators of average salt removal rate, charge efficiency and removed salt normalized energy consumption, ICC/single-pass and SCC/single-pass are the two most superior operational modes, followed by OC/single-pass, ICC/batch-mode and SCC/batch-mode. Further considering the advantage of SCC in the continuous charge neutralization and electrode regeneration, SCC/single-pass operational mode can be deemed optimal.

Water pollution and freshwater scarcity are two of the most important environmental problems faced by human around the globe in the 21st century. Capacitive deionization (CDI), as a promising electrochemical water treatment technology, has attracted large attention over the past decade for the facile removal of ions from water with the advantages of environmental friendliness, cost effectiveness, low energy consumption, and convenient electrode regeneration. Enormous progress has been made in the CDI research field and now CDI encompasses various cell architectures assembled with either capacitive electrodes or battery electrodes. These scientific advances are accompanied by a diverse application of CDI-based technologies. This work is intended to summarize the versatile applications of CDI and highlight the representative achievements in each of the applications primarily covering water desalination, water purification, water disinfection, resource recovery and synergistic combination with other technologies. Emerging application areas of CDI such as energy harvesting and CO2 capture are also presented. Lastly, the challenges and future outlook for CDI practical applications are discussed. This work should be of value in promoting CDI-based technologies to develop into a competitive option for coping with multiple water or energy-related issues.

Phosphorus (P) concentrations as low as 10 mg/L P can lead to eutrophication in natural waters. Meanwhile, phosphorus is an important and non-renewable resource for humans, animals and plants. This study investigated the removal and recovery of phosphorus from low-strength wastewaters by flow-electrode capacitive deionization (FCDI) to realize the sustainable utilization of phosphorus. Effects of different operating parameters on the performance of FCDI for phosphorus removal were systematically studied, including applied voltage, flow rate and flow direction of feed water, initial phosphorus concentration, carbon black content and initial pH value. Results showed that the applied voltage and initial pH value had great influence on the phosphorus removal efficiency. The removal efficiency of phosphorus reached about 97% when the operating parameters were optimized. The FCDI system possessed good removal performance of phosphorus after six consecutive cycling tests. In addition, the low concentration of feed phosphorus solution (100 mg/L P) could be effectively concentrated by 16 times after 11 h of operation through the enrichment experiment, leading to a final concentration of 16.8 mg/L P in feed solution and 1567 mg/L P in the aqueous phase of flow electrodes. To conclude, these results revealed that FCDI system is effective in phosphorus removal and recovery, and has great application prospects in treatment of phosphorous wastewaters.

Considering that urban expansion and increase of human activities represent important threats to biodiversity and ecological processes in short and long term, developing protected area (PA) network with high connectivity is considered as a valuable conservation strategy. However, conservation planning associated with the large-scale network in China involves important information loopholes about the land cover and landscape connectivity. In this paper, we made an integrative analysis for the identification of conservation priority areas and least-cost ecological corridors (ECs) in order to promote a more representative, connected and efficient ecological PA network for this country. First, we used Zonation, a spatial prioritization software, to achieve a hierarchical mask and selected the top priority conservation areas. Second, we identified optimal linkages between two patches as corridors based on least-cost path algorithm. Finally, we proposed a new framework of China's PA network composed of conservation priority and ECs in consideration of high connectivity between areas. We observed that priority areas identified here cover 12.9% of the region, distributed mainly in mountainous and plateau areas, and only reflect a spatial mismatch of 19% with the current China's nature reserves locations. From the perspective of conservation, our result provide the need to consider new PA categories, specially located in the south (e.g., the middle-lower Yangtze River area, Nanling and Min-Zhe-Gan Mountains) and north regions (e.g., Changbai Mountains), in order to construct an optimal and connected national network in China. This information allows us better opportunities to identify the relative high-quality patches and draft the best conservation plan for the China's biodiversity in the long-term run.