Emerging Contaminants in the Effluent of Wastewater Should Be Regulated: Which and to What Extent?

Effluent discharged from urban wastewater treatment plants (WWTPs) is a major source of emerging contaminants (ECs) requiring effective regulation. To this end, we collected discharge datasets of pharmaceuticals (PHACs) and endocrine-disrupting chemicals (EDCs), representing two primary categories of ECs, from Chinese WWTP effluent from 2012 to 2022 to establish an exposure database. Moreover, high-risk ECs' long-term water quality criteria (LWQC) were derived using the species sensitivity distribution (SSD) method. A total of 140 ECs (124 PHACs and 16 EDCs) were identified, with concentrations ranging from N.D. (not detected) to 706 µg/L. Most data were concentrated in coastal regions and Gansu, with high ecological risk observed in Gansu, Hebei, Shandong, Guangdong, and Hong Kong. Using the assessment factor (AF) method, 18 high-risk ECs requiring regulation were identified. However, only three of them, namely carbamazepine, ibuprofen, and bisphenol-A, met the derivation requirements of the SSD method. The LWQC for these three ECs were determined as 96.4, 1010, and 288 ng/L, respectively. Exposure data for carbamazepine and bisphenol-A surpassed their derived LWQC, indicating a need for heightened attention to these contaminants. This study elucidates the occurrence and risks of ECs in Chinese WWTPs and provides theoretical and data foundations for EC management in urban sewage facilities.

Evaluation of the DGT passive samplers for integrating fluctuating concentrations of pharmaceuticals in surface water.

Diffusive gradients in thin films (DGTs) have been well-documented for the measurement of a broad range of organic pollutants in surface water. However, the performance has been challenged by the inherent periodic concentration fluctuations for most organic pollutants. Therefore, there is an urgent need to assess the true time-weighted average (TWA) concentration based on fluctuating concentration profiles. The study aimed to evaluate the responsiveness of DGT and accuracy of TWA concentrations, considering various concentration fluctuating scenarios of 20 pharmaceuticals in surface water. The reliability and accuracy of the TWA concentrations measured by the DGT were assessed by comparison with the sum of cumulative mass of DGT exposed at different stages over the deployment period. The results showed that peak concentration duration (1-5 days), peak concentration fluctuation intensity (6-20 times), and occurrence time of peak concentration fluctuation (early, middle, and late stages) have minimal effect on DGT's response to most target pharmaceutical concentration fluctuations (0.8 < CDGT/CTWA < 1.2). While the downward-bent accumulations of a few pharmaceuticals on DGT occur as the sampling time increases, which could be accounted for by capacity effects during a long-time sampling period. Additionally, the DGT device had good sampling performance in recording short fluctuating concentrations from a pulse event returning to background concentrations with variable intensity and duration. This study revealed a satisfactory capacity for the evaluation of the TWA concentration of pharmaceuticals integrated over the period of different pulse deployment for DGT, suggesting that this passive sampler is ideally suited as a monitoring tool for field application. This study represents the first trial for evaluating DGT sampling performance for pharmaceuticals with multiple concentration fluctuating scenarios over time, which would be valuable for assessing the pollution status in future monitoring campaign.

Cardiac commitment driven by MyoD expression in pericardial stem cells.

Cellular therapy holds immense promise to remuscularize the damaged myocardium but is practically hindered by limited allogeneic sources of cardiac-committed cells that engraft stably in the recipient heart after transplantation. Here, we demonstrate that the pericardial tissue harbors myogenic stem cells (pSCs) that are activated in response to inflammatory signaling after myocardial infarction (MI). The pSCs derived from the MI rats (MI-pSCs) show in vivo and in vitro cardiac commitment characterized by cardiac-specific Tnnt2 expression and formation of rhythmic contraction in culture. Bulk RNA-seq analysis reveals significant upregulation of a panel of genes related to cardiac/myogenic differentiation, paracrine factors, and extracellular matrix in the activated pSCs compared to the control pSCs (Sham-pSCs). Notably, we define MyoD as a key factor that governs the process of cardiac commitment, as siRNA-mediated MyoD gene silencing results in a significant reduction of myogenic potential. Injection of the cardiac-committed cells into the infarcted rat heart leads to long-term survival and stable engraftment in the recipient myocardium. Therefore, these findings point to pericardial myogenic progenitors as an attractive candidate for cardiac cell-based therapy to remuscularize the damaged myocardium.

Occurrence, Source Apportionment, and Ecological Risk of Typical Pharmaceuticals in Surface Waters of Beijing, China.

Various studies have shown that the heavy use of pharmaceuticals poses serious ecological risks, especially in metropolitan areas with intensive human activities. In this study, the spatial distribution, sources, and ecological risks of 29 pharmaceuticals in 82 surface waters collected from the North Canal Basin in Beijing were studied. The results showed that the pharmaceutical concentrations ranged from not detected to 193 ng/L, with ampicillin being undetected while ofloxacin had a 100% detection frequency, which indicates the widespread occurrence of pharmaceutical pollution in the North Canal Basin. In comparison with other freshwater study areas, concentrations of pharmaceuticals in the North Canal Basin were generally at moderate levels. It was found that pharmaceutical concentrations were always higher in rivers that directly received wastewater effluents. Source analysis was conducted using the positive matrix factorization model. Combining the spatial pollution patterns of pharmaceuticals, it has been found that wastewater effluents contributed the most to the loads of pharmaceuticals in the studied basin, while in suburban areas, a possible contribution of untreated wastewater was demonstrated. Risk assessment indicated that approximately 55% of the pharmaceuticals posed low-to-high ecological risks, and combining the results of risk analyses, it is advised that controlling WWTP effluent is probably the most cost-effective measure in treating pharmaceutical pollution.

Influence of watershed characteristics and human activities on the occurrence of organophosphate esters related to dissolved organic matter in estuarine surface water.

Organophosphate esters (OPEs) are widespread in aquatic environments and pose potential threats to ecosystem and human health. Here, we profiled OPEs in surface water samples of heavily urbanized estuaries in eastern China and investigated the influence of watershed characteristics and human activities on the spatial distribution of OPEs related to dissolved organic matter (DOM). The total OPE concentration ranged from 22.3 to 1201 ng/L, with a mean of 162.6 ± 179.8 ng/L. Chlorinated OPEs were the predominant contaminant group, accounting for 27.4-99.6 % of the total OPE concentration. Tris(2-chloroisopropyl) phosphate, tris(1,3-dichloro-2-propyl) phosphate, and tributyl phosphate were the dominant compounds, with mean concentrations of 111.2 ± 176.0 ng/L, 22.6 ± 21.5 ng/L, and 14.8 ± 14.9 ng/L, respectively. Variable OPE levels were observed in various functional areas, with significantly higher concentrations in industrial areas than in other areas. Potential source analysis revealed that sewage treatment plant effluents and industrial activities were the primary OPE sources. The total OPE concentrations were negatively correlated to the mean slope, plan curvature, and elevation, indicating that watershed characteristics play a role in the occurrence of OPEs. Individual OPEs (triisobutyl phosphate, tris(2-butoxyethyl) phosphate, tris(2-chloroethyl) phosphate, and tricresyl phosphate) and Σalkyl-OPEs were positively correlated to the night light index or population density, suggesting a significant contribution of human activity to OPE pollution. The co-occurrence of OPEs and DOM was also observed, and the fluorescence indices of DOM were found to be possible indicators for tracing OPEs. These findings can elucidate the potential OPE dynamics in response to DOM in urbanized estuarine water environments with intensive human activities.

[Simultaneous determination of four N-lauryl amino acid surfactants in facial cleansers by high performance liquid chromatography-ultraviolet detection].

Significant developments have recently been achieved in the field of N-lauryl amino acid (NLAA) surfactants derived from renewable resources. Compared with conventional surfactants, NLAAs exhibit remarkable surfactant properties, exceptional biodegradability, good biocompatibility, and high safety profiles. These attributes have led to the widespread use of NLAAs in personal-care products. The detection methods employed for NLAAs include two-phase titration (TT), spectrophotometric analysis (SA), and high performance liquid chromatography (HPLC). However, because both TT and SA measure the total concentration of anionic active matter, identifying and quantifying individual compounds in a sample containing multiple anionic surfactants is impossible. The presence of cationic surfactants in the sample also introduces interferences, which lead to significant errors. Compared with TT and SA, HPLC offers direct and rapid testing procedures. However, compounds with no or weak UV-visible light absorption exhibit low sensitivity when detected by UV, necessitating the use of detectors such as differential refractive index detectors (RIDs), evaporative light scattering detectors (ELSDs), or charged aerosol detectors (CADs). Most HPLC users consider UV light as the fundamental configuration of the instrument, and other detectors are less commonly employed. Therefore, establishing a new HPLC method suitable for the UV detection of NLAAs is of practical significance. In this study, a novel HPLC-UV method was developed for the simultaneous detection of N-lauryl glutamine (LG), N-lauryl glycine (LC), N-lauryl alanine (LA), and N-lauryl sarcosine (LS) by optimizing the mobile-phase composition and selecting an appropriate chromatographic column and detection wavelength. The samples were mixed with acetonitrile-0.10% H3PO4 aqueous solution (60∶40, v/v) and sonicated for 10 min, then stayed at room temperature for 5 min. Subsequently, the mixture was filtered through a 0.22 µm filter membrane and separated on an Agilent Eclipse Plus C18 column (150 mm×4.6 mm, 5 µm). The mobile phase used for separation consisted of acetonitrile-0.10% H3PO4 aqueous solution at a flow rate of 1.0 mL/min. The detection wavelength was set at 205 nm, and the injection volume was 10 µL. The results demonstrated that the four NLAAs exhibited good linearity in the range of 2.0-800.0 mg/L, with correlation coefficients (r)≥0.9995. The limits of detection (LODs) ranged from 0.17 to 0.49 mg/L, and limits of quantification (LOQs) ranged from 0.57 to 1.63 mg/L. The relative standard deviations (RSDs) for precision, repeatability, and stability over 24 h were all below 2.0%. Using this method, the NLAA contents of five facial-cleanser products were determined. The results demonstrated that all five samples contained one or more NLAAs, and the total NLAA contents ranged from 64.58 to 97.01 mg/g. The five spiked-sample recoveries of the NLAAs at four different spiked levels (0.60, 4.50, 15.00, 24.00 mg/g) ranged from 94.3% to 107.4%, indicating satisfactory accuracy. However, the actual NLAA composition and label for one facial-cleanser product were not consistent with our test results. This finding demonstrates the necessity of strengthening market monitoring through testing. The proposed method has the advantages of simple pretreatment, rapid testing, good precision, high accuracy, and appropriate stability. Thus, it is suitable for the determination of NLAA contents in facial cleansers and provides an effective technical reference for the raw-material purity assessment, synthetic yield detection, and product quality control of this type of surfactant.

Depth-dependent variations of physicochemical properties of sedimentary dissolved organic matter and the influence on the elimination of typical pharmaceuticals.

Sedimentary dissolved organic matter (DOM) could exert a significant influence on the transformation of trace organic contaminants. However, the variations of sedimentary DOM properties with depth and their impact on trace organic contaminants biodegradation remain unclear. In this study, the qualitative changes in DOM properties with depth were assessed using spectral techniques. Specifically, within the sediment range of 0-30 cm, humic acid and fulvic acid fractions exhibited higher degrees of humification and aromatization at 10-20 cm, while hydrophilic fractions showed higher degrees of humification and aromatization at 20-30 cm. Furthermore, electrochemical methods were employed to quantitatively assess the electron transfer capacity of sedimentary DOM at different depths, which displayed consistent variation trend with humification and aromatization degree. The high degree of humification and aromatization, along with strong electron-accepting capability of DOM, significantly enhanced the biodegradation rates of tetracycline and ritonavir. To gain deeper insights into the influence of molecular composition of DOM on its properties, two-dimensional gas chromatography-quadrupole mass spectrometry analysis revealed that quinones and phenolic hydroxyl compounds govern the redox reactivity of DOM. Simulated experiment of DOM-mediated biodegradation of typical pharmaceuticals confirmed the role of quinones and phenolic hydroxyl groups in the redox reactivity of DOM.

Sfrp1 as a Pivotal Paracrine Factor in the Trained Pericardial Stem Cells that Foster Reparative Activity.

Tissue damage often induces local inflammation that in turn dictates a series of subsequential responses, such as stem cell activation and growth, to maintain tissue homeostasis. The aim of the study is to testify the possibility of using inflammation-trained stem cells as optimal donor cells to augment the efficacy of cell therapy. The pericardial stem/stromal cells derived from the animals after myocardial infarction (MI-pSC) showed an enhanced myogenic potential and augmented reparative activity after transplantation in the injured hearts, as compared to the Sham-pSC. Bulk RNA-Seq analysis revealed significant upregulation of a panel of myogenic and trophic genes in the MI-pSC and, notably, Sfrp1 as an important anti-apoptotic factor induced robustly in the MI-pSC. Injection of the MI-pSC yielded measurable numbers of surviving cardiomyocytes (Tunel and Casp-3 negative) within the infarct area, but the effects were significantly diminished by siRNA-based silence of Sfrp1 gene in the pSC. Primed Sham-pSC with pericardial fluid from MI rats mimicked the upregulation of Sfrp1 and enhanced myogenic potential and reparative activity of pSC. Taken together, our results illustrated the inflammation-trained pSC favor a reparative activity through upregulation of Sfrp1 gene that confers anti-apoptotic activity in the injured cardiomyocytes. Therefore, the active form of stem cells may be used as a cardiac protective agent to boost therapeutical potential of stem cells.

A landscape source-sink model to understanding the seasonal dynamics of antibiotics in soils at watershed scale.

Human and veterinary antibiotics occur widely in soil ecosystems and pose a serious threat to soil health. Landscape structure can be linked to Earth surface processes and anthropogenic footprints and may influence the variability of antibiotics in soil. In this study, an improved landscape source-sink model was used to characterize source-sink structures using the location-weighted landscape index (LWLI), which can be linked to antibiotic seasonality. The topographic wetness index was employed to identify source and sink landscapes, which represent antibiotic transport pathways via topography-driven hydrological processes. The results indicate that LWLI values and antibiotic seasonality are typically higher in farmland soils than in forest and orchard soils. LWLI values exhibit significant positive correlations with antibiotic seasonality in soils (R2: 0.33-0.58). Furthermore, landscape source-sink structures have a significant influence on antibiotic seasonality between winter and other seasons in farmland soils; however, these structures affect antibiotic seasonality between summer and other seasons in forest and orchard soils. The results of this study indicate that water movement regulated by landscape structure may play a crucial role in influencing antibiotic seasonality in soils at the watershed scale, and the landscape source-sink model can be used to quantitatively evaluate antibiotic seasonality in soil environment.

Urbanization and land use regulate soil vulnerability to antibiotic contamination in urban green spaces.

The presence of antibiotics in environment is an emerging concern because of their ubiquitous occurrence, adverse eco-toxicological effects, and promotion of widespread antibiotic resistance. Urban soil, which plays a noticeable role in human health, may be a reservoir of antibiotics because of intensive human disturbance. However, little is understood about the vulnerability of soil to antibiotic contamination in urban areas and the spatial-temporal characteristics of anthropogenic and environmental pressures. In this study, we developed a framework for the dynamic assessment of soil vulnerability to antibiotic contamination in urban green spaces, combining antibiotic release, exposure, and consequence layers. According to the results, soil vulnerability risks shown obvious spatial-temporal variation in urban areas. Areas at a high risk of antibiotic contamination were usually found in urban centers with high population densities and in seasons with low temperature and vegetation coverage. Quinolones (e.g., ofloxacin and norfloxacin) were priority antibiotics that posed the highest vulnerability risks, followed by tetracyclines. We also confirmed the effectiveness of the vulnerability assessment by correlating soil vulnerability indexes and antibiotic residues in urban soils. Furthermore, urbanization- and land use-related parameters were shown to be critical in regulating soil vulnerability to antibiotic contamination based on sensitivity analysis. These findings have important implications for the prediction and mitigation of urban soil contamination with antibiotics and strategies to improve human health.

A double-cycle echo state network topology for time series prediction.

Echo state network (ESN) has gained wide acceptance in the field of time series prediction, relying on sufficiently complex reservoir connections to remember the historical features of the data and using these features to obtain the outputs by a simple linear readout. However, the randomness of its input and reservoir connections pose negative impacts on the prediction performance and performance stability of the models, the complexity of reservoir connections brings high time consumption during network computing, and the presence of randomness and complexity makes the hardware implementation of the ESN difficult. In response, we propose a double-cycle ESN (DCESN) based on the Li-ESN model, which has fixed weights to improve prediction performance and performance stability and simpler reservoir connections compared to the classical ESN to reduce the time consumption. The existence of both greatly reduces the difficulty of hardware implementation of the ESN and provides many conveniences for the future application of the ESN. Experimental results on many widely used time series datasets show that the DCESN has comparable or even better prediction performance than the ESN and good robustness against noise and parameter fluctuations.

An innovative risk evaluation method on soil pathogens in urban-rural ecosystem.

The presence and reproduction of pathogens in soil environment have significant negative impacts on soil security and human health in urban-rural ecosystem. Rapid urbanization has dramatically changed the land use, soil ecosystems, and the presence of pathogens in soil environment, however, the risk associated with soil pathogens remains unknown. Identifying the potential risk of pathogens in soils in urban-rural ecosystem has become an urgent issue. In this study, we established a risk evaluation method for soil pathogens based on analytic hierarchy process and entropy methods to quantitatively estimate the potential risk of soil pathogens to children and adults in urban-rural ecosystem. The abundance and species number of soil pathogens, network structure of soil microbial community, and human exposure factors were considered with 12 indicators to establish the risk evaluation system. The results revealed that 19 potential pathogenic bacteria were detected in soils within a typical urban-rural ecosystem. Substantial differences were observed in both abundance and species of soil pathogens as well as network structure of soil microbial community from urban to rural areas. Urban areas exhibited relatively lower levels of soil pathogenic abundance, but the microbial network was considerably unstable. Rural areas supported relatively higher levels of soil pathogenic abundance and stable microbial networks. Notably, peri-urban areas showed relatively unstable microbial networks alongside higher levels of soil pathogenic abundance compared to other areas. The risk evaluation of soil pathogens for both adults and children showed that peri-urban areas presented the highest potential risk, with children being more susceptible than adults to threats posed by soil pathogens in both urban and peri-urban areas. The established evaluation system provides an innovative approach for quantifying risk of soil pathogens at regional scale and can be used as a reference for preventing soil pathogens contamination and enhancing soil health in areas with intense human activities.

The microbial oxidation of pharmaceuticals in an anaerobic aqueous environment: Effect of dissolved organic matter fractions from different sources.

Previous studies have demonstrated the importance of dissolved organic matter (DOM) on the biodegradation of trace organic contaminants occurred in the hyporheic zone. However, the role of diverse DOM fractions with distinct physicochemical properties on the biodegradation of pharmaceuticals under reducing conditions is scarcely known. To address this knowledge gap, DOMs derived from road-deposited sediment, soil, and active sludge (namely allochthonous DOM) and algae (namely autochthonous DOM) were collected and isolated into different fractions. Thereafter, the effect of DOM fractions on the anaerobic microbial oxidation of two typical pharmaceuticals, i.e., ritonavir (RTV) and tetracycline (TC) was explored by using simulated anaerobic microcosms. Mechanistic insights into how DOM fractions from different sources influence pharmaceutical biodegradation processes were provided by optical and electrochemical analyses. Results showed that humic acid and fulvic acid fractions from allochthonous DOM could enhance the biodegradation of TC (12.2 % per mgC/L) and RTV (14.5 % per mgC/L), while no significant impact was observed for that of hydrophilic fractions. However, autochthonous DOM promoted the biodegradation of TC (4.17 % per mgC/L) and inhibited that of RTV. Mechanistic analysis showed that the higher of humification and aromatization level of DOM components, the stronger their promotive effect on the biodegradation of TC and RTV. Further, the promotive mechanism could be attributed to the response of quinone moieties in DOM as extracellular electron acceptors that yields more energy to support microbial metabolism. These results provide a more comprehensive understanding of diverse DOM fractions mediating microbial anaerobic oxidation of trace organic pollutants, and extend our insights into contamination control and remediation technologies.

Triple-Mode upconversion emission for dynamic multicolor luminescent anti-Counterfeiting.

Lanthanide (Ln3+) luminescent materials play a crucial role in information security and data storage owing to their excellent and unique optical properties. The advances in dynamic colorful luminescent anti-counterfeiting nanomaterials enable the generation of a high-level information encryption. In this work, a superior thermal, optical wavelength and excitation power triple-mode stimuli-responsive emission color modulation is demonstrated in a lanthanide-doped nanostructured luminescent material. The plentiful emission colors are manipulated by modulating the composition of a fluoride core-shell nanostructure with different Ln3+ at different doping concentrations. The nanomaterials display remarkable excitation wavelength/power-dependent color change, along with temperature-dependent color variation in the range from 298 K to 437 K, with a good relative sensitivity Sr of 1.1387% K-1 at 398 K. The universal optical modulation, combined with the excellent optical and structural stability of the luminescent nanoparticles, renders many advantages for the anti-counterfeiting application. This work explores a universal strategy for the manipulation of triple-mode stimuli-responsive dynamic luminescence and demonstrates its good potential for anti-counterfeiting application.

Linking pharmaceutical residues to dissolved organic matter and aquatic bacterial communities in a highly urbanized bay.

Pharmaceuticals are causing environmental concerns associated with their widespread distribution in aquatic ecosystems. The environmental fate and behavior of pharmaceutical residues are related to dissolved organic matter and bacterial communities, both of which are strongly influenced by human activities. However, the relationships among pharmaceutical pollution, dissolved organic matter pool, and bacterial community structure under the pressure of human activities are still unclear, especially in highly urbanized bay areas. In this study, we investigated the occurrence and distribution of 35 pharmaceuticals in a typical urbanized bay (Hangzhou Bay) in Eastern China, and analyzed their relationships with dissolved organic matter and aquatic bacterial community structure. The target pharmaceuticals were ubiquitously detected in surface water samples, with their concentrations ranging from undetectable to 263 ng/L. The detected pharmaceuticals were mostly sulfonamides, macrolides, antidepressants, and metabolites of stimulants. Significant positive correlations were observed between the concentrations of pharmaceuticals and the intensity of human activities. Strong correlations also emerged between the concentration of antidepressants and the speed of urban expansion, as well as between the concentration of cardiovascular drugs and the population density or nightlight index. Three fluorescent components (protein-like C1, terrestrial humic-like C2, protein tryptophan-like C3) were significantly positively correlated with the total concentration of pharmaceuticals. Pharmaceutical pollution reshaped aquatic bacterial communities, based on the close correlation observed between pharmaceutical concentration and bacterial community structure. The results elucidate the potential dynamics of dissolved organic matter pool and aquatic bacterial communities in response to pharmaceutical pollution in urbanized bay ecosystems.

Pharmaceutical active compounds in a heavily industrialized and urbanized bay, Eastern China.

Bays are transition zones connecting freshwater ecosystems and marine ecosystems, and they are strongly influenced by intensive human activities. Pharmaceuticals are of concern in bay aquatic environments because of their potential threat to marine food web. We studied the occurrence, spatial distribution, and ecological risks of 34 pharmaceutical active compounds (PhACs) in Xiangshan Bay, a heavily industrialized and urbanized area in Zhejiang Province, Eastern China. PhACs were ubiquitously detected in the coastal waters of the study area. A total of twenty-nine compounds were detected in at least one sample. Carbamazepine, lincomycin, diltiazem, propranolol, venlafaxine, anhydro erythromycin, and ofloxacin had the highest detection rate (≥ 93%). These compounds were detected with maximum concentrations of 31, 127, 0.52, 1.96, 2.98, 75, and 98 ng/L, respectively. Human pollution activities included marine aquacultural discharge and effluents from the local sewage treatment plants. These activities were the most influential sources in this study area based on principal component analysis. Lincomycin was an indicator of veterinary pollution of coastal aquatic environment, and the concentrations of lincomycin were positively related to the total phosphorus in this area (r = 0.28, p < 0.05). Typical PhACs such as venlafaxine, ofloxacin, norfloxacin, roxithromycin, and clarithromycin were significantly and positively correlated with nitrate and total nitrogen (r > 0.26, p < 0.05) based on Pearson's correlation analysis. Carbamazepine was negatively correlated with salinity (r < - 0.30, p < 0.01). Land use pattern was also correlated with the occurrence and distribution of PhACs in the Xiangshan Bay. Some PhACs, i.e., ofloxacin, ciprofloxacin, carbamazepine, and amitriptyline posed medium to high ecological risks to this coastal environment. The results of this study could be helpful to understand the levels of pharmaceuticals, potential sources, and ecological risks in marine aquacultural environment.

Urbanization-land-use interactions predict antibiotic contamination in soil across urban-rural gradients.

Antibiotics ubiquitously occur in soils and pose a potential threat to ecosystem health. Concurrently, urbanization and land-use intensification have transformed soil ecosystems, but how they affect antibiotic contamination remain largely unknown. Therefore, we profiled a broad-scale pattern of antibiotics in soil from agricultural lands and green spaces across urbanization gradients, and explored the hypothetical models to verify the effects of urbanization and land-use intensity on antibiotic contamination. The results showed that antibiotic concentrations and seasonality were higher in agricultural soil than in green spaces, which respectively showed linear or hump-shaped declines along with the increasing distance to urban centers. However, the response of antibiotic pollution to land-use intensity depended strongly on the urbanization level. More importantly, interactions between urbanization and land-use explained, on average, 59.6 % of the variation in antibiotic concentrations in soil across urbanization gradients. The proposed interactions can predict the non-linear changes in soil vulnerability to antibiotic contamination. Our study revealed that the urbanization can modulate the effects of land-use intensity on antibiotic concentration and seasonality in the soil environment, and that there is high stress on peri-urban soil ecosystems due to ongoing land-use changes arising from rapid urbanization processes.

[Distribution of Biodegradable Dissolved Organic Matter and Its Affecting Factors in a Typical Peri-urban Watershed in Yangtze River Delta].

Dissolved organic matter (DOM) plays key roles in the carbon biogeochemical cycle, and biodegradable dissolved organic matter (BDOM) is one of the key fractions of DOM. Rapid urbanization and intensive human activities substantially influence the distribution of DOM at the watershed scale. Identifying the spatial and temporal variability in BDOM has become an important and urgent issue of water quality control in rapid urbanization areas. However, limited studies have been conducted to explore the role of human activities on the occurrence and distribution of BDOM in peri-urban watersheds. In this study, the spatial and temporal distribution of BDOM and related affecting factors were investigated in a typical peri-urban watershed (Zhangxi watershed) located at Ningbo City in Yangtze River Delta. Water samples were collected in wet and dry seasons in 2019 based on topographic features, land use, and intensity of human activities. The BDOM were characterized by fluorescence excitation-emission matrix and parallel factor analysis (EEM-PARAFAC), and land use patterns were analyzed using the Source-Sink Landscape Model. The results of this study showed that the BDOM concentrations ranged from 0.57 to 6.80 mg·L-1. Obvious spatial and temporal heterogeneities of BDOM were found at the watershed scale, and significantly higher concentrations of BDOM were observed in the wet season than those in the dry season. Furthermore, relatively high concentrations of BDOM were found in areas with relatively higher intensive human activities. Two fluorescent components (a terrestrial humic-like substance and protein-like substance) were observed using the PARAFAC model. The results of spatial analysis showed that terrestrial humic-like fluorescent components were closely positively correlated with anthropogenic parameters (percentages of agricultural and urban land and ratio of source and sink landscapes). The results showed that the occurrence and distribution of BDOM were strongly influenced by human activities, which could provide scientific guidance for water quality control and related land management in peri-urban aquatic ecosystems.

Design and analysis of in-plane and out-of-plane heterostructures based on monolayer tri-G with enhanced photocatalytic property for water splitting.

Photocatalytic water splitting is considered to be a promising renewable solution to the energy crisis and environmental problems as an inexhaustible clean energy source. Graphene has an ultrahigh carrier mobility, but the zero gap limits its practical application in the photocatalysis field. Graphane has a wider band gap and retains a high carrier mobility, which demonstrates its great potential in this field. However, the broad band gap results in low photocatalytic efficiency. In this work, we propose two effective ways to modulate its electronic structure, modifying the structure of graphane and constructing a heterojunction using density functional calculations. We systematically investigated four trilayer graphane (tri-G) conformers and designed in-plane (lateral) and out-of-plane (vertical) heterojunctions with tri-G and chair-G (cha-G), the two most stable graphanes, with theoretical prediction. The results show that tri-G not only has a smaller band gap, falling in the ultraviolet range, which enhances the UV-light catalytic performance, but also has tunable band edge positions, locating outside the reduction potential of hydrogen and oxidation potential of water. Furthermore, the calculated electron effective mass for the tri-G conformers is smaller than that of cha-G. What's more, the band gap, band edge position, and photocatalytic efficiency are further optimized by constructing heterojunctions. In particular, both the in-plane and out-of-plane tri-G-C/cha-G heterostructures are confirmed as direct band gap semiconductors and type-I heterostructures exhibiting special band alignment, meanwhile satisfying the requirements for water splitting. And the band gaps of the heterostructures are further reduced. In addition, metal doping is expected to further optimize their electronic structure. These results provide theoretical support and a feasible modulation strategy for developing graphane as an effective photocatalyst for water splitting.

Assessment of heavy metals contamination and human health risk assessment of the commonly consumed medicinal herbs in China.

This study investigates heavy metal contamination of commonly consumed medicinal herbs and human health risks to the Chinese population arising from the consumption of herbs that contain potentially harmful elements. Food safety standards for Chinese residents are becoming stricter, and much work in this field needs to be performed. This study examines Co, Ba, Fe, Cr, Mn, Ni, Zn, As, Cd, Pb, Cu, Be, Sb, and Bi concentrations in four regularly consumed Chinese herb species: Radix Paeoniae Alba (RPA), Radix Angelicae Dahuricae (RAD), Rhizoma Atractylodis Macrocephalae (RAM), and Radix Puerariae (RP). A pollution status examination and evaluation of heavy metals in RPA, RAD, RAM, and RP were performed. The human health risk assessment associated with the intake of potentially harmful elements in herbs was calculated in terms of the estimated daily intake (EDI), the target hazard quotient (THQ), the estimated hazard index (HI), and the lifetime cancer risk (CR). The mean single-factor pollution index (PI) showed that in the RPA, RAD, RAM, and RP samples, approximately 10.0%, 10.0%, 30.0%, and 10.0%, respectively, were polluted by Cd. The present study indicated that the pattern of consumption of the studied herbs in China does not seem to suggest an excessive health hazard associated with any of the toxic elements studied.