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A new innovative methodology system framework for source apportionment and source-specific risk assessment has been proposed and actively applied to identify the contamination characteristics, oriented sources and health risks associated with contamination levels of Heavy metals (HMs) and Polycyclic Aromatic Hydrocarbons (PAHs) in soils, a typical cold agricultural region in Northeastern China. To achieve this meaningful goal, a large-scale dataset including 1780 top soil samples, 10 HMs and 16 priority PAHs has been organized and collected from a typical study area in China. The total concentrations of the 10 selected HMs in study area range from 0.05 to 2147.40 mg/kg, with an average of 549.25 ± 541.37 mg/kg. The average concentrations of PAHs for (3-6)-rings are 16.60 ± 18.90, 26.40 ± 28.20, 9.51 ± 13.00 and 1.99 ± 5.30 ng/g, respectively. On the base of optimized literature source fingerprints for HM and PAH, a widely used receptor model, positive matrix factorization (PMF) has been applied to apportion the contamination sources HMs and PAHs in soils. Then source-specific health risk of soil HMs and PAHs have been assessed using the probabilistic incremental lifetime cancer risk model incorporated with source apportionment results data. Fertilizer residues/coke oven comprise the primary contamination source contributors of HMs and PAHs with corresponding contributions of 32.23 % and 27.93 % for HMs and 37.94 % for PAHs. Fertilizer/pesticide residues contributes most to the risks of soil HMs (28.8 %), followed by fossil fuel combustion (24.6 %), mining activities (20.2 %), traffic and vehicle emission (16.3 %) and electroplating/dyeing (14.1 %). Meanwhile, the ranking of health risks from the five identified contamination sources of soil PAHs are resident discharge, coal-fired boilers, coke oven emission, gasoline combustion and power plant, with the contribution of 27.1 %, 25.3 %, 17.3 %, 15.5 % and 14.8 %. And relatively, source-specific risk assessment demonstrates fossil fuel and coal combustion contribute the greatest impact to the total risk of HMs and PAHs (61.7 % and 56.1 %), respectively. This study provides a good example of how the source specific health risk assessment can be utilized to reduce the contamination in soils., Competing Interests: Declaration of competing interest We claim no conflicts of interest with other people or organizations that can inappropriately influence our work., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Combined remediation technologies are increasingly being considered to uranium contaminated groundwater, such as the joint utilize of permeable reactive bio-barrier (Bio-PRB) and electrokinetic remediation (EKR). While the assessment of uranium plume evolution in the combined remediation system (CRS) have often been impeded by insufficient understanding of multi-physical field superposition. Therefore, advanced knowledge in multi-physical field coupling in groundwater flow will be crucial to the practical application of these techniques. A two-dimensional multi-physical field coupling model was constructed for predicting the uranium degradation in CRS. The study demonstrates that the coupling model is able to predict the uranium plume evolution and rapidly evaluate the performance of CRS components. The results show that field electric direction and flow field strength are the key factors that affect the retardation and remediation performance of CRS. The reverse electric field direction significantly affected the contact reaction time of uranium in the system. The uranium residence time in the reverse electric field was 3.8 d, which was significantly greater than the original electric field (2.0 d). Depending on the voltage, the reverse electric field direction was 16%-36% more efficient than the original direction. The strength of the flow field was about two orders of magnitude higher than that of the electric field, so the groundwater flow rate dominated remediation efficiency. Reducing the flow rate by 1/2 could improve the performance of the system by approximately 66%. In addition, the coupling model can be utilized to design standard CRS for real site of uranium contaminated groundwater. To meet the optimal performance, the direction of the electric field should be set opposite to the flow field. This work has successfully used a coupling model to predict uranium contaminant-plume evolution in CRS and estimate the performance of each component., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Microbial community, as the decomposers of constructed wetland (CW), plays crucial role in biodegradation and biotransformation of pollutants, nutrient cycling and the maintenance of ecosystem balance. In this study, 9 water samples, 6 sediment samples, and 8 plant samples were collected in Annan CW, which has the functions of water treatment and wetland culture park. The characteristics of microbial community structure in different media were illustrated by using of high-throughput sequencing-based metagenomics approach and statistical analysis. Meanwhile, this study identified and classified human pathogens in CW to avoid potential risks to human health. The results showed that dominant bacteria phyla in CW include Proteobacteria, Bacteroides, Actinobacteria, Firmicutes and Verrucomicrobia. The distribution of microorganisms in three media is different, but not significant. And the pH and DO profoundly affected microbe abundance, followed by water temperature. The microbial diversity in sediments is the highest, which is similar with the detection of human pathogens in sediments. Moreover, compared with Calamus, Lythrum salicaria and Reed, Scirpus tabernaemontani has fewer pathogenic microorganisms. The distribution of microorganisms in the CW is complex, and a variety of human pathogens are detected, which is more prone to create potential risks to human health and should receive additional attention., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Hyporheic zone (HZ) systems have a natural purification capacity, and they are commonly used to provide high quality drinking water. However, the presence of organic contaminants in HZ systems in anaerobic environments causes the aquifer sediments to release metals (e.g., Fe) at levels above drinking water standards, which affects the quality of groundwater. In this study, the effects of typical organic pollutants (dissolved organic matter (DOM)) on Fe release from anaerobic HZ sediments were investigated. Ultraviolet fluorescence spectroscopy, three-dimensional excitation-emission matrix fluorescence spectroscopy, excitation-emission matrix spectroscopy coupled with parallel factor analysis and Illumina MiSeq high-throughput sequencing were used to determine the effects of the system conditions on Fe release from HZ sediments. Compared with the control conditions (low traffic and low DOM as a baseline), the Fe release capacity was enhanced by 26.7 % and 64.4 % at low flow rate (85.8 m/d) and high organic matter concentration (1200 mg/L), which was consistent with the residence-time effect. The transport of heavy metals under different system conditions varied with the influent organic composition. The influent organic matter composition and fluorescence parameters (the humification index, biological index and fluorescence index) were closely related to the release of the Fe effluent, while these factors had less influence on Mn and As. From 16S rRNA analysis of the aquifer media at different depths at the end of the experiment, under low flow rate and high influent concentration conditions, reduction of Fe minerals by Proteobacteria, Actinobacteriota, Bacillus, and Acidobacteria promoted the release of Fe. These functional microbes play an active role in the Fe biogeochemical cycle in addition to reducing Fe minerals to promote Fe release. In summary, this study reveals the effects of the flow rate and influent DOM concentration on the release and biogeochemistry of Fe in the HZ. The results presented herein will contribute to a better understanding of the release and transport of common groundwater contaminants in the HZ and other groundwater recharge environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Tri(1,3-dichloropropyl) phosphate (TDCPP) is widespread in the environment as a typical thyroid hormone-disrupting chemical. Here, we aimed to explore the toxicological mechanisms of the thyroid hormone-disrupting effects induced by TDCPP in zebrafish embryos/larvae using multi-omics analysis. The results showed that TDCPP (400 and 600 µg/L) induced phenotypic alteration and thyroid hormone imbalance in zebrafish larvae. It resulted in behavioral abnormalities during zebrafish embryonic development, suggesting that this chemical might exhibit neurodevelopmental toxicity. Transcriptomic and proteomic analysis provided consistent evidence at the gene and protein levels that neurodevelopmental disorders were significantly enhanced by TDCPP exposure (p < 0.05). Additionally, multi-omics data indicated that membrane thyroid hormone receptor (mTR)-mediated non-genomic pathways, including cell communication (ECM-receptor interactions, focal adhesion, etc.) and signal transduction pathways (MAPK signaling pathway, calcium signaling pathway, neuroactive ligand-receptor interaction pathway, etc.), were significantly disturbed (p < 0.05) and might contribute to the neurodevelopmental toxicity induced by TDCPP. Therefore, behavioral abnormalities and neurodevelopmental disorders might be important phenotypic characteristics of TDCPP-induced thyroid hormone disruption, and mTR-mediated non-genomic networks might participate in the disruptive effects of this chemical. This study provides new insights into the toxicological mechanisms of TDCPP-induced thyroid hormone disruption and proposes a theoretical basis for risk management of this chemical., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Lakes act as one of the reservoirs and dispersal routes of antibiotic resistance genes (ARGs) and pathogenic resistant bacteria in aquatic environments. Previous studies reported the occurrence and distribution of ARGs in lakes worldwide; however, few investigated the biogeography and diversity patterns of antibiotic resistome in the environment. To fill this gap, a large-scale data set of sediment metagenomes was collected from globally distributed lakes and characterized comprehensively using metagenomic assembly-based analysis, aiming to shed light on the biogeography and diversity patterns of ARGs in lake ecosystems from a global perspective. Our analyses showed that abundant and diverse ARGs were found in the global lake sediments, including a set of emerging ARGs such as mcr-type and carbapenem-resistant Enterobacteriaceae related genes. Most of the identified ARGs were generally associated with the commonly used antibiotics, suggesting the role of increasing antibiotic consumptions on the resistome prevalence. Spatially, the composition and diversity of ARGs varied across geographical distances and exhibited a scale-dependent distance-decay relationship. Notably, the composition of ARGs was largely shaped by bacterial community structure, and their diversities were co-governed by stochastic process (∼48%) and deterministic process (∼52%). Findings provide a valuable insight to better understand ecological mechanisms of ARGs in lake ecosystems and have important implication for the prevention and control of resistome risk., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)

Methyl parathion (MP) is a typical organophosphorus pesticide that is widely used worldwide, and hydrolysis, oxidation and reduction are the main abiotic degradation processes. Manganese dioxide (MnO 2 ) and organic acid can participate in various geochemical processes of pollutants, a reaction system was constructed to degrade MP using δ-MnO 2 and oxalic acid. The δ-MnO 2 /oxalic acid reaction system could efficiently degrade MP, and the removal rate of MP (20 μM) reached 67.83% within 30 h under the optimized conditions (pH 5, [δ-MnO 2 ] = 2 mM, [oxalic acid] = 100 mM). MP was hydrolyzed by substitution reactions of S N @P and S N @C, and reduced by conversion of the nitro groups (-NO 2 ) in MP and its hydrolysates to amino groups (-NH 2 ). The primary active substance produced in the reaction system was the complexes dominated by Mn(III)-oxalic acid. This study provides a scientific basis for the degradation of organophosphorus pesticides using MnO 2 and an organic acid. The results have important theoretical significance and application value for pollution control and remediation of organophosphorus pesticides., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Aquatic sediment polluted by potentially toxic elements (PTEs) from mining activities represents a potential health "time bomb" for humans and the local ecology, but the integrated analysis of pollution and hazards of PTEs in sediment around typical metal mines in China is limited. Presently, the associated pollution status, spatial distribution, and ecological and health hazards of Cd, Cu, Zn, Pb, Cr, and As were investigated through index evaluation, spatial analysis, health risk assessment models, and Monte Carlo simulation. Overall, the sediment exhibited varying degrees of PTE contamination; notably, the level of Cd was 104.85 times higher than its background value, and it became the most enriched element in the surveyed sediment, followed in descending order by Cu, As, Zn, Pb, and Cr. Nationally, over 64.5% of metal-mining-affected sediment presented a very high ecological risk, contributed mostly by Cd (43.2%-98.7%) followed by As, Pb, and Cu; the risk contributed by both Cr and Zn was found to be negligible. The adverse health risk posed to children by most sediment was 1.72 and 6.46 times higher than that posed to adults for cancerous and noncancerous risks, respectively. The potential noncarcinogenic risks were mainly caused by As, which contributed over 78.9% of the Hazard Index values, then followed by Pb (>9.3%). For both children and adults, the carcinogenic risk of PTEs decreased in the following order: As > Cd > Cr > Pb. The investigated sediment was found seriously affected by nearby metal mines, especially those in regions with long-term and large-scale nonferrous-metal-mining activities. This study could provide a reference for policymakers to develop control strategies for PTE pollution in sediment around mining areas., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Antimicrobial resistance (AMR) is one of the significant global issues to public health. Compared to other aquatic environments, research on AMR in groundwater is scarce. In the study, a meta-analysis was conducted to explore the characteristics and risks of antibiotics and antibiotic resistance genes (ARGs) in global groundwater, using a data set of antibiotic concentrations collected from publications during 2000-2021 and a large-scale metagenomes of groundwater samples (n = 330). The ecotoxicological risks of antibiotics in the global groundwater were evaluated using mixture risk quotient with concentration addition model to consider the synergistic effects of multiple antibiotics. Bioinformatic annotations identified 1413 ARGs belonging to 37 ARG types in the global groundwater, dominated by rifamycin, polyketide, and quinolone resistance genes and including some emerging ARGs such as mcr-family and carbapenem genes. Relatively, the level of ARGs in the groundwater from spring was significantly higher (ANOVA, p < 0.01) than those from the riparian zone, sand and deep aquifer. Similarly, metal resistance genes (MRGs) were prevalent in the global groundwater, and network analysis suggested the MRGs presented non-random co-occurrence with the ARGs in such environments. Taxonomic annotations showed Proteobacteria, Actinobacteria, Eukaryota, Acidobacteria and Thaumarchaeota were the dominant phylum in the groundwater, and the microbial community largely shaped profile of ARGs in the environment. Notably, the ARGs presented co-occurrence with mobile genetic elements, virulence factors and human bacterial pathogens, indicating potential dissemination risk of ARGs in the groundwater. Furthermore, an omics-based approach was used for health risk assessment of antibiotic resistome and screened out 152 risk ARGs in the global groundwater. Comparatively, spring and cold creek presented higher risk index, which deserves more attention to ensure the safety of water supply., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

A metagenomics-based technological framework has been proposed for evaluating the potential and utility of FEAST as an ARG profile-based source apportionment tool. To this end, a large panel of metagenomic data sets was analyzed, associating with eight source types of ARGs in environments. Totally, 1089 different ARGs were found in the 604 source metagenomes, and 396 ARG indicators were identified as the source-specific fingerprints to characterize each of the source types. With the source fingerprints, predictive performance of FEAST was checked using "leave-one-out" cross-validation strategy. Furthermore, artificial sink communities were simulated to evaluate the FEAST for source apportionment of ARGs. The prediction of FEAST showed high accuracy values (0.933 ± 0.046) and specificity values (0.959 ± 0.041), confirming its suitability to discriminate samples from different source types. The apportionment results reflected well the expected output of artificial communities which were generated with different ratios of source types to simulate various contamination levels. Finally, the validated FEAST was applied to track the sources of ARGs in river sediments. Results showed STP effluents were the main contributor of ARGs, with an average contribution of 76 %, followed by sludge (10 %) and aquaculture effluent (2.7 %), which were basically consistent with the actual environment in the area., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Riverbank filtration (RBF) constitutes an important part of the water cycle, which involves active natural filtration leading to pollution of river water being intercepted and retained. The RBF has the function of water purification, but retention of exogenous pollutants in the RBF system complicates biogeochemical processes due to the presence of primary active components. In this study, we verified the essential role of microbial mediation during the interactions between primary Fe minerals in the RBF system and dissolved organic matter (DOM) in river water based on lab-scale experiments. The results demonstrated that DOM from infiltration of river water increased the amount of iron (Fe) released from the sediment in RBF, leading to an increase in Fe concentration in groundwater by higher than one order of magnitude. In particular, the existence of Fe bacteria even made this effect more thorough and more complex. Abiotic reduction was shown to play a more significant role in increasing Fe release than microbe-mediated reduction. Increasing the amount of Fe released could change the distribution of Fe minerals at the sediment surface, thereby affecting the structure of the microbial community in the RBF system and decreasing the DOM concentration in the groundwater. Moreover, As and Mn were found to behave in a similar manner as Fe due to their close biochemical properties when interacting with primary minerals in sediment. This study not only provides mechanistic insight into the higher Fe concentrations encountered in the groundwater of nearby rivers but also has important practical implications for developing nature-based technologies for water pollution control and environmental remediation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

As a green technology, constructed wetlands (CWs) can provide a low-cost solution for wastewater treatment. Either as a standalone treatment or integrated with conventional treatment, nutrients, antibiotic resistant bacteria (ARB)/antibiotic resistance genes (ARGs) can be removed by CW efficiently. While, few studies have focused on characteristics of resistome and bacterial community (BC) structure in CW during dormant period. Therefore, in this study, Annan CW (a full-scale hybrid CW) was selected to characterize resistome and BC during dormant period. The profiles of bacteria / ARGs were monitored in combination of shotgun sequencing and metagenomic assembly analysis. And multidrug ARGs are the most abundant in Annan CW, and surface flow wetland had the relatively high ARG diversity and abundance compared with subsurface flow wetland and the front pond. The most dominant phylum in CW is Proteobacteria, while the other dominant phylum in three parts have different order. COD, TP, TN, ARGs, and mobile genetic genes (MGEs) were removed by subsurface flow CW with better performance, but virulent factors (VFs) were removed by surface flow CW with better performance. Based on the spatiotemporal distribution of ARGs, the internal mechanism of ARGs dynamic variation was explored by the redundancy analysis (RDA) and variation partitioning analysis (VPA). BCs, MGEs and environmental factors (EFs) were responsible for 45.6 %, 28.3 % and 15.4 % of the ARGs variations. Among these factors, BCs and MGEs were the major co-drivers impacting the ARG profile, and EFs indirectly influence the ARG profile. This study illustrates the specific functions of ARG risk elimination in different CW components, promotes a better understanding of the efficiency of CWs for the reduction of ARG and ARB, contributing to improve the removal performance of constructed wetlands. And provide management advice to further optimize the operation of CWs during dormant period., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

An analytical algorithm coupling free-phase migration, precipitation, and natural attenuation through volatilization and biodegradation (FPVB) was developed to calculate the flux of light nonaqueous-phase liquid (LNAPL) leaking from unsaturated zone to groundwater. Sandbox and soil column experiments were performed to identify the LNAPL migration characteristics and states to provide data to establish and verify FPVB algorithm. For free-phase migration, the Kinematic Oily Pollutant Transport (KOPT) model was used to determine LNAPL movement velocity and leakage time. The correlations of water saturation, residual LNAPL saturation and the cumulative dissolution ratio of residual LNAPL were described using an empirical formula for the precipitation leaching process. Equations for diesel volatilization kinetics and first order degradation were used to describe the natural attenuation processes. Coupling the algorithms for the different stages gave the final FPVB algorithm. The FPVB algorithm was used to describe the pollution situation at a real site, and the results were consistent with the actual situation. The FPVB algorithm could be used to quickly assess the scale and degree of pollution with little information on the parameters for the actual LNAPL leakage event., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Currently, most researches focus on that constructed wetlands (CWs) achieve desirable removal of antibiotics, antibiotic resistance genes (ARGs) and human pathogens. However, few studies have assessed the fate of resistome components, especially the behavior and cooccurrence of ARGs, mobile genetic elements (MGEs) and virulence factors (VFs). Therefore, characteristics of microbial communities (MCs) in CWs and their receiving rivers also deserve attention. These factors are critical to water ecological security. This study used two CWs to explore the fate of resistome components and characteristics of MCs in the CWs and their receiving river. Eleven samples were collected from the two CWs and their receiving river. High-throughput profiles of ARGs and microbial taxa in the samples were characterized. 31 ARG types consisting of 400 subtypes with total relative abundance 42.63-84.94× /Gb of sequence were detected in CWs, and 62.07-88.08× /Gb of sequence in river, evidencing that ARG pollution covered CWs and the river, and implying huge potential risks from ARGs. MGEs and VFs were detected, and tnpA, IS91 and intI1 were the three dominant MGEs, while Flagella. Type IV pili and peritrichous flagella were main VFs. Both CWs can remove ARGs, MGEs and VFs efficiently. However, some ARGs were difficult to remove, such as sul1 and sul2, and certain ARGs remained in the effluent of the CWs. The co-occurrence of ARGs, MGEs, and VFs implies the risk of antibiotic resistance and dissemination of ARGs. Eighty-five types of human pathogen were detected in the river samples, particularly Pseudomonas aeruginosa, Bordetella bronchiseptica, Aeromonas hydrophila and Helicobacter pylori. Correlation analysis indicated that MCs had significant effects on the profiles of ARGs in the water environment. This study reveals potential risks of the reuse of reclaimed water, and illustrates the removal ability of ARGs and related elements by CWs. This study will be helpful for monitoring and managing resistomes in water environments., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be constructed as influencing the position presented in, or the review of the manuscript entitled “Fate of Resistome Components and Characteristics of Microbial Communities in Constructed Wetlands and Their Receiving River”., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Due to extensive water exchanges and abundant active biochemical compositions, active and complex hydrogeochemical processes often exist in riverbank filtration (RBF). The distribution of microbes is considered to be profoundly affected by these processes and is considered to impact the hydrogeochemical processes and the migration and transformation of water pollutants in turn and then impact the water quality. The distribution of microbes and their response to the physiochemical properties along a vertical RBF profile perpendicular to the Songhua River in Northeast China was explored by using 16 S rRNA and redundancy analysis (RDA). The results showed that various microbes were found in the vertical riparian filter (RBF) curve, including Actinobacteria, Proteobacteria, Acidobacteria, Chloroflexi, and Firmicutes. With increasing depth (vertical) and distance from the river (lateral), the microbial community and diversity in the RBF sediment profile decreased. Nitrospirota, Pseudomonas, Gammaproteobacteria, Ochrobactrum, Acinetobacter and Desulfobacterota of the RBF core taxa were also significantly correlated with the biotransformation behavior of typical groundwater pollutants (ammonia, Fe, Mn and S). The amount of As in the RBF is too low to sustain microbial survival. Some microbes in RBF can also degrade natural organic pollutants. This study not only revealed the spatial distribution of geological microbes under the impact of hydrological processes but also lays a foundation for the further study of the hydrobiogeochemical processes of active biochemical compositions in groundwater and water quality evolution, which is of positive significance to ensure the quality safety of the drinking water supplied by RBFs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

The effluents of sewage treatment plants (eSTP) are one of the critical contributors of antibiotic resistiome in rivers. Recently, community coalescence has been focused as the entire microbiome interchanges with one another. While works have reported the prevalence of antibiotic resistance genes (ARGs) in eSTP and their effects on river resistome, little research has investigated the extent of resistome coalescence in the environment. In the study, we have addressed the issue and focused on the resistome coalescence of eSTP in an urban river with a typical effluent/river coalescence model, by utilizing high-throughput sequencing (HTS)-based metagenomic assembly analysis. In all, a total of 609 ARGs were found in the eSTP-river system, conferring resistance to 30 antibiotic classes and including some emerging ARGs such as mcr-type, tetX and carbapenemase genes. Statistical analyses including linear discriminant analysis effect size (LEfSe) showed the coalescence of STP effluents increased the diversity and abundance of river resistome, indicating its low resistance to disturb the invasion of resistome community in eSTP. After coalescence in the river, the imprints of STP-derived ARGs presented a temporary increase and gradually decreased trend along the flow path. Further, an innovative fast expectation-maximization microbial source tracking (FEAST) method was used to quantitatively apportion the coalescence event, and demonstrated the contribution of eSTP on river resistome and its attenuation dynamics in the downstream. Notably, correlation-based network analysis and contig-based co-occurrence analysis showed the coalesced resistome in the downstream river co-occurred with human bacterial pathogens, mobile genetic elements and virulence factor genes, indicating potential resistome dissemination risk in the environment. This study provides more profound understanding of resistome coalescence between engineered and natural contexts, which is helpful for optimizing strategies to prevent and control resistome risk in aquatic environment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier Ltd.)

The reuse of urban reclaimed water is conducive to alleviate the current serious shortage of water resources. However, antibiotic resistance genes (ARGs) in reclaimed water have received widespread attention due to their potential risks to public health. Deciphering the fate of ARGs in reclaimed water benefits the development of effective strategies to control resistome risk and guarantees the safety of water supply of reclaimed systems. In this study, the characteristics of ARGs in an integrated reclaimed water system (sewage treatment plant-constructed wetland, STP-CW) in Beijing (China) have been identified using metagenomic assembly-based analysis, as well as the combined effect of the STP-CW system on the reduction of antibiotic resistome. Results showed a total of 29 ARG types and 813 subtypes were found in the reclaimed water system. As expected, the STP-CW system improved the removal of ARGs, and about 58% of ARG subtypes were removed from the effluent of the integrated STP-CW system, which exceeded 43% for the STP system and 37% for the CW system. Although the STP-CW system had a great removal on ARGs, abundant and diverse ARGs were still found in the downstream river. Importantly, network analysis revealed the co-occurrence of ARGs, mobile genetic elements and virulence factors in the downstream water, implying potential resistome dissemination risk in the environment. Source identification with SourceTracker showed the STP-effluent was the largest contributor of ARGs in the downstream river, with a contribution of 45%. Overall, the integrated STP-CW system presented a combined effect on the reduction of antibiotic resistome, however, the resistome dissemination risk was still non-negligible in the downstream reclaimed water. This study provides a comprehensive analysis on the fate of ARGs in the STP-CW-river system, which would benefit the development of effective strategies to control resistome risk for the reuse of reclaimed water., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Exploring the relationships between heavy metal release and salinity can help address the problems of combination of toxic heavy metals and salinization in contaminated soils. Therefore, in this study, the release characteristics of heavy metals (Cd, Cu and Zn) under different salt types and mass concentrations were investigated through batch desorption experiments. Spearman's correlation analysis was performed to assess the effects of typical physicochemical properties on metal release under salt stress. The results indicated that the types and concentration gradients of salt had notably different impacts on the release of different metals; specifically, there were significant impacts for Cd but slight impacts for Cu and Zn. MgCl 2 and CaCl 2 had more obvious promoting effects on Cd release, followed by a salt mixture and NaCl, and this pattern was similar for Zn release. Most salts could slightly restrain the release of Cu, except for MgCl 2 and Na 2 SO 4 , which had slight promoting effects. Moreover, low levels of CaCl 2 could effectively restrain the release of Cu. The results showed that the release capacities of metals followed the order of Cd > Cu > Zn, possibly attributed to the competitive adsorption among cations. Ferromanganese oxides in the soil favored the release of Cd and Zn under salt treatments, and redox potential was an important factor affecting Cu release. The results also suggested that the background values of metals could affect metal release, but the effects were varied under different salt treatments for Zn. The reason for this may be that the addition of different salts changed the effects of certain soil properties on the metal release. Overall, this study can serve as an important reference for controlling heavy metal pollution in soils in salinization and coastal areas., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The groundwater in many aquifers contains elevated concentrations of iron (Fe). Although much of this Fe is from its release from water-bearing sediments under natural environmental conditions, sufficient evidence is lacking to clarify whether anthropogenic pollutants, such as dissolved organic matter (DOM), can increase this natural release. In this time series and comparative analysis study, an Fe increasing effect was verified through laboratory leaching tests. The influences of the aqueous environmental conditions, such as pH, were also investigated. DOM can promote the release of Fe from sediments and increase the concentration of Fe in groundwater. In addition, lower or higher pH and temperature can enhance the release of Fe to some extent. Higher concentrations of DOM provided a more thorough release of Fe from the sediment; additional ions such as Cu also affected Fe release. It is possible that complexation between DOM and Fe occurs through ligand dissolution and reduction, thus promoting the release of Fe. The findings indicate that DOM imported through anthropogenic activities can increase the release of Fe from aquifer sediments into groundwater, thus worsening Fe pollution in groundwater. This study explored the mechanism by which different types of DOM release Fe from aquifer sediments and investigated the factors that influence this process. The findings provide insights into the geochemical processes of Fe in the groundwater., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Polycyclic aromatic compound (PAC) contamination in soil as a result of oil spills is a serious issue because of the huge global demand for fossil energy. This study assessed the vertical variation in polycyclic aromatic hydrocarbons (PAHs), derivatives of PAHs (dPAHs) and bacterial community structure in deep soil with long-term contamination by oil spillage. Our results suggest that the content of total PACs ranged from 1196.6 μg/kg to 14980.9 μg/kg and decreased with depth at all sites. PAHs were the most abundant PACs, with a mean concentration of 6640.7 μg/kg, followed by oxygenated PAHs (mean 156.3 μg/kg) and nitrated PAHs (mean 33.4 μg/kg). PAHs are mainly low molecular weight PACs such as naphthalene, fluorene and phenanthrene, while derivatives of PAHs are all low molecular weight PACs and mainly oxygenated PAHs. Low molecular weight PAHs were an important source of dPAHs under specific conditions. The bacterial community structure showed higher bacterial diversity and lower bacterial richness in shallow soil (2-6 m in depth) than in deep soil (8-10 m in depth). Spearman's analysis confirmed that dramatic bacterial community shifts are a response to contamination. At the genus level, the presence of PACs highly selected for Pseudomonas, belonging to Proteobacteria. Moreover, functional predictions based on Tax4Fun revealed that soil with long-term contamination had a strong potential for PAC degradation. In addition, statistical analysis showed that oxidation-reduction potential (Eh) was closely related to variations of bacterial community composition and function. Finally, Ramlibacter, Pseudomonas, Pseudonocardia, c&#95;MB-A2-108, f&#95;Amb-16S-1323, and Qipengyuania were identified by cooccurrence network analysis as keystone taxa contributing to the maintenance of bacterial ecological function. Together, our results provide evidence of tight bacterial effects of PAHs and dPAHs and a more complete understanding of the fate of PACs in deep contaminated soils., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

With the ongoing development and utilization of nuclear energy, uranium pollution has become an increasingly serious issue. Although many adsorbents are able to remove hexavalent uranium (U(VI)) from aqueous solution, the development of a high capacity adsorbent exhibiting superior stability would be beneficial. Grafting poly(amidoxime) (PAO) onto reduced graphene oxide (rGO) provides suitable U(VI) adsorption performance but the PAO is prone to agglomeration. The present work used density functional theory calculations to predict that PAO would bond with pyrrolic N atoms in nitrogen-doped rGO (N-rGO). To confirm this, PAO-grafted rGO (PAO-rGO) and PAO-grafted N-rGO (PAO-N-rGO) were prepared and characterized and the successful grafting of PAO on N-rGO was demonstrated. Adsorption experiments demonstrated that PAO-N-rGO exhibit superb U(VI) adsorption performance compared with the original PAO-rGO under acidic conditions. As for competing metal ions, Cu 2+ , Al 3+ , and Ca 2+ have a greater impact on U(VI) adsorption than Na + , Mg 2+ , and K + both for PAO-rGO and PAO-N-rGO. The maximum adsorption capacities of PAO-rGO and PAO-N-rGO for U(VI) were calculated to be 1500.26 and 1545.95 mg g -1 , respectively. The mechanism of nitrogen doping promoting uranium(VI) adsorption can be attributed to enhanced PAO grafting and improvement of adsorption performance of the rGO. This work demonstrates that nitrogen doping is a viable strategy for enhancing the U(VI) adsorption performance of PAO-rGO.

Peat-derived organic matter, as powerful chelators, is of great significance for the transport of Fe to the ocean and the enhancement of dissolved Fe. However, the iron binding capacity of molecular weight (MW)-fractionated dissolved organic matter is variable, due to its structure and composition heterogeneity. In this work, we used the standard Pahokee Peat fulvic acid (PPFA) as an example, and investigated the spectroscopy properties and Fe(III) binding ability of PPFA and different molecular weight fractions by UV−Vis absorbance and fluorescence spectroscopy and the Donnan Membrane Technique (DMT). The results showed binding sites for Fe(III) at the 263 nm and >320 nm regions in differential absorbance spectra. Upon increasing the iron concentration to 18.00 μmol·L−1, the critical binding capacity was exceeded, which resulted in a decrease in absorbance. Fe(III) was found to prefer to bind to humic-like components, and ultraviolet humic-like fluorophores displayed stronger binding strength. High molecular weight PPFA fractions (>10 kDa) possessed more aromatic and hydrophobic components, displayed a higher degree of humification, and exhibited higher metal binding potential. Furthermore, the speciation analysis and stability constant (cK) were calculated using Donnan membrane equilibrium. The correlation between cK values and PPFA spectral properties demonstrated that aromaticity, hydrophobicity, molecular weight and humification degree were crucial indices of PPFA−Fe(III) affinity. Significantly, the humification degree, represented by HIX, showed the strongest correlation (r = 0.929, p = 0.003), which could be used to estimate the binding strength. This study provides further understanding of the complexation mechanism of iron and DOM in the peat environment and identifies the considerable effect of molecular weight.

Dissolved organic matter (DOM) in soil is a key factor affecting the bioavailability of heavy metals, but very few studies have focused on the role of DOM in the use of soil amendments to mitigate heavy metal accumulation in crops. Here, eleven materials were added to cadmium (Cd)-contaminated paddy soil in greenhouse pot trials; rice was grown and harvested, the chemodiversity of post-harvest soil DOM was characterized using Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry, and the specific associations between soil DOM traits and water-extractable soil Cd concentration were identified at the molecular level. The results showed that the endogenous release caused by altering soil pH had a greater effect on soil DOM concentration than did the exogenous chemical input due to the application of organic amendments, which in turn contributed to the chemodiversity of DOM. After one season of rice cultivation, soil DOM molecules were mainly dominated by relatively low molecular weight heteroatom-free lignins. C/N, C/H ratios of organic materials influenced DOM molecular fingerprint patterns, and soil pH and redox potential were the main driving forces affecting the chemodiversity of DOM. Furthermore, the low molecular weight, high saturation, low aromaticity, and heteroatom-free DOM molecules are more likely to dissolve Cd from the soil solid phase, thus increasing the potential risk of Cd to the environment. The results provide critical information about amendments-induced changes in DOM chemodiversity and will inform the selection of appropriate soil amendments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Heavy metals pollution in groundwater and the resulting health risks have always been an environmental research hotspot. However, the available information regarding this topic and associated methods is still limited. This study collected 98 groundwater samples from a typical agricultural area of Songnen Plain in different seasons. The pollution status and sources of ten heavy metals (As, Ba, Cd, Co, Cr (VI), Cu, Fe, Mn, Ni, Pb, and Zn) were then analyzed and compared. In addition, the human health risks assessment (HHRA) model was used to calculate human health risks caused by heavy metals in groundwater. The results revealed that heavy metals were mainly distributed in the northwest of the study area and along the upper reaches of the Lalin river and that the concentrations of heavy metals were higher during the wet season than the dry season. Industrial and agricultural activities and natural leaching are the main sources, and each kind of heavy metal may have different sources. Fe and Mn are the primary pollutants, mainly caused by the native environment and agricultural activities. The exceeding standard rates are 71.74% and 61.54%, respectively based on the Class III of Quality Standard for Groundwater of China (GB/T 14848-2017). The maximum exceeding multiple are 91.45 and 32.05, respectively. The health risks of heavy metals borne by different groups of people were as follows: child > elder > young > adult. Carcinogenic heavy metals contribute to the main risks, and the largest risks sources are Cr and As. Therefore, the government should appropriately restrict the use of pesticides and fertilizers, strictly manage the discharge of enterprises, and control man-made heavy metals from the source. In addition, centralized water supply and treatment facilities shall be established to prevent the harm of native heavy metals.

In this study, a new integrated multidisciplinary-based framework has been proposed to better understand the environmental risks of heavy metals (HMs) in agricultural soils. The source apportionment results revealed by a multilinear engine model were incorporated into the geochemical indexes and the probabilistic health risk assessment models for identifying the source-oriented risks of HMs in the environment. High-throughput sequencing-based metagenomic assembly analysis was used for characterizing the prevalence and dissemination risk of antibiotic resistomes and their associations with the geochemical enrichment of HMs in the soils. Results showed agricultural and industrial activities were the main sources of HMs in the environment. Although the soils were contaminated moderately by HMs and the health risks posed by soil metals were negligible for both adult and children, source-oriented risk evaluation suggested agricultural activities contributed relatively higher contamination and health risks than the other sources. Notably, abundant and diverse antibiotic resistant genes, mobile gene elements, virulence factors, and antibiotic-resistant bacterial pathogens were identified in the agricultural soils, as well as their co-occurrences on the same contigs, implying a non-negligible resistome risk. Further, statistical and network analyses showed the geochemical enrichment of HMs exerted significant effects on the antibiotic resistomes in the environment., (Copyright © 2021 Elsevier B.V. All rights reserved.)

90 groundwater samples and 14 surface water samples were collected in wet season (summer) and dry season (winter) in the North China Plain (NCP), and analyzed for 11 organophosphorus pesticides (OPPs). The results showed that the main types of OPPs in surface water and groundwater were dimethoate, dichlorvos, methyl-parathion, malathion in both summer and winter. The OPP concentrations in groundwater and surface water were higher in summer than in winter. In the vertical direction, the distribution characteristics of different four types of groundwater sampling points are different. In the horizontal direction: farmland adjacent to a river (FAR) > central farmland (CF) > nonfarm area adjacent to a river (NFAR) > central nonfarm area (CNF). The OPPs concentrations in surface water adjacent to farmland were higher than that in surface water adjacent to nonfarm area. The main factors influencing the distribution of OPPs in the groundwater and surface water were the interaction process between them, the groundwater flow field and the OPPs used in agricultural activities. The ecological risk of OPPs to surface water was greater in summer than in winter. Water Flea was at medium risk, and malathion had the greatest influence on Water Flea in both summer and winter. The non-carcinogenic and carcinogenic risks of the four main OPPs in surface water were higher than in groundwater, and were higher in summer than in winter, but they would not lead to adverse health effects on local residents., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Anthropogenic pollutants (organic nitrogen and ammonia) can change the dynamic balances of hydrogeochemical components of groundwater, and this can affect the fates of the pollutants and groundwater quality. The aim of this paper is to assess the long-term impact of pollutants on groundwater component concentrations and species in three sites that has been polluted with illegal discharge wastewater containing organic nitrogen and ammonia, in order to reveal the interactions between nitrogen species and Mn. We analyzed semi-monthly groundwater data from three sites in northwestern China over a long period of time (2015-2020) by using statistical analyses, correlation analyses, and a correlation co-occurrence network method. The results showed that wastewater entering groundwater from surface changed the hydrogeochemical component concentrations and species significantly. The main form of inorganic nitrogen species changed from nitrate to ammonia. The Mn concentration increased from undetectable (<0.01 mg/L) to 1.64 mg/L (the maximum), which surpassed the guideline value suggested by China and WHO. The main mechanism for Mn increase is the reductive dissolution of Mn oxide caused by the oxidation of organic nitrogen. Mn‑nitrogen species interaction complicates the transformation of nitrogen components. Chemoautotrophic denitrification and dissimilatory nitrate reduction to ammonium (DNRA) mediated by Mn are the major mechanisms of nitrate attenuation when dissolved oxygen is greater than 2 mg/L. Mn oxides reductive dissolution and reoxidation of Mn by nitrate reduction cause Mn to circulate in groundwater. The results provide field evidence for interactions between nitrogen species transformation and Mn cycle in groundwater. This has important implications for pollution management and groundwater remediation, particularly monitored natural attenuation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

This study focused on the processes of free infiltration, precipitation displacement, and natural attenuation of the LNAPL under the condition of near-surface leakage. Sandbox experiments were performed to explore the migration characteristics of LNAPL in the vadose zone with two media structures and the influences of the soil interface on the migration of LNAPL. The results indicate that the vertical migration velocity of the LNAPL infiltration front in medium and coarse sand was 1 order of magnitude higher than that in fine sand and that the LNAPL accumulated at the coarse-fine interface, which acted as the capillary barrier. Displacement of precipitation for LNAPL had little relationship with rainfall intensity and was obviously affected by medium particle size, where coarse sand (40.78%) > medium sand (20.5%) > fine sand (10%). The natural attenuation rate of the LNAPL in the vadose zone was related to the water content of the media; the natural attenuation rate of fine sand was higher. This study simulated the process of the LNAPL leakage from the near surface into the layered heterogeneous stratum, improved the understanding of the migration of the LNAPL under different stratum conditions, and can provide support for the treatment of LNAPL leakage events in the actual site.

The abuse of illicit drugs has led to their extensive detection worldwide and subsequently exerted adverse effects upon aquatic organisms and ecosystem. However, less attention has been paid to the uptake, biotransformation, internal distribution, and toxicokinetic processes in the exposed organisms. In this study, zebrafish (Danio rerio) was exposed to methamphetamine (METH) and ketamine (KET) at three different concentrations in a semi-static exposure system. METH and KET, together with their metabolites, amphetamine (AMP) and norketamine (NK), were consistently detected in zebrafish. Over 14-day exposure, the relative magnitude of mean concentrations of illicit drugs in zebrafish generally followed the order of brain > liver > intestine > ovary > muscle. The uptake rate constants (K u ) of METH and KET were in the range of 0.590-1.38 × 10 3 L/(kg·d), the elimination rate constants (K e ) were in the range of 0.18-6.98 1/d, and the half-lives were in the range of 0.18-6.98 d, respectively. METH and KET demonstrated relatively rapid uptake and elimination kinetics and short half-lives, and concentrations in organs were driven by external concentrations. Illicit drugs were not persistent within zebrafish organs when there were no substantial external contaminant sources. The observed values of bioconcentration factor (BCF o , L/kg) and kinetically-derived bioconcentration factor (BCF k , L/kg) were at the similar level. The ability of different zebrafish organs accumulating target chemicals from the aquatic environment was different, and brain was the target organ of the test illicit drugs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Here, a new integrated methodology framework has been proposed for source apportionment and source-oriented risk evaluation, and applied to identify the characteristics, sources and health risks of PAHs in the soils of a typical cold region in Northeastern China. To this end, a large-scale data set containing 1780 soil samples and 16 priority PAHs has been collected from the study area. Two advanced receptor models, positive matrix factorization (PMF) and multivariate curve resolution-weighted alternating least-squares (MCR-WALS), have been comparatively employed to apportion the pollution sources of soil PAHs, with the help of a set of modified literature PAH source fingerprints. Further, the apportionment results have been incorporated into a probabilistic incremental lifetime cancer risk model for assessing the source-specific health risk of soil PAHs. Notably, the PMF and MCR-WALS models have apportioned essentially same results. The coal combustion and gasoline engine are identified as the main contributors of soil PAHs, with contributions of 57.9-58.1% and 25.2-22.2%, respectively. The health risks posed by PAHs in the soils are negligible for both adult and children; relatively, source-oriented risk assessment shows coal combustions make the largest contribution to the total risk of PAHs (56.1%), followed by gasoline engine (22.5%) and coke oven (21.4%)., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Sodium percarbonate (SPC) and peroxymonocarbonate (PMC) have been widely used in modified Fenton reactions because of their multiple superior features, such as a wide pH range and environmental friendliness. This broad review is intended to provide the fundamental information, status and progress of SPC and PMC based decontamination technologies according to the peer-reviewed papers in the last two decades. Both SPC and PMC can directly decompose various pollutants. The degradation efficiency will be enhanced and the target contaminants will be expanded after the activation of SPC and PMC. The most commonly used catalysts for SPC activation are iron compounds while cobalt compositions are applied to activate PMC in homogenous and heterogeneous catalytical systems. The generation and participation of hydroxyl, superoxide and/or carbonate radicals are involved in the activated SPC and PMC system. The reductive radicals, such as carbon dioxide and hydroxyethyl radicals, can be generated when formic acid or methanol is added in the Fe(II)/SPC system, which can reduce target contaminants. SPC can also be activated by energy, tetraacetylethylenediamine, ozone and buffered alkaline to generate different reactive radicals for pollutant decomposition. The SPC and activated SPC have been assessed for application in-situ chemical oxidation and sludge dewatering treatment. The challenges and prospects of SPC and PMC based decontamination technologies are also addressed in the last section., (Copyright © 2020. Published by Elsevier B.V.)

Heavy metal pollution has been a global concern and key points of environmental pollution prevention and control due to the growing problems of urbanization and industrialization. Rapidly and correctly apportioning sources of heavy metal is still a great challenge because of the stability of source fingerprint and complex interaction of multiple contaminants and sources. In this study, we perform a combination of optimization of pollution source fingerprint and source apportionment through jointly utilizing two machine classification and screening methods for characterizing the pollution sources of heavy metal in the sediments of an urban river and its surrounding soils. Dominance-based rough set model (DRS), content optimization tools, and multivariate curve resolution-alternating least squares model (MCR-WALS) were employed to screen representative pollution source samples, optimize pollution source fingerprint, and apportion the potential sources of heavy metals, respectively. Further, Support vector machine (SVM) was adopted to correspondence analysis results and pollution fingerprint based on the factor characteristics for achieving source apportionment accurately. Results showed that the pollution source pollution source fingerprints optimized by DRS and optimization tools are more representative and stable, and the results obtained by SVM and MCR-WALS are more accurate comparing with traditional methods. As whole, source apportionment suggested that printing and dyeing, chemical, electroplating, metal processing were the main origins of heavy metals in this area and the proportions of them in sediment and soil pollution sources were 67.05% and 28.43%, respectively. Besides, coal combustion was also the main sources of heavy metal pollution in soils, accounting about 34.16%. Results of the study can advance our knowledge to better understand the characterization of heavy metal pollution in the peri-urban ecosystem and to design effective targeted strategies for reducing heavy metal pollution diffusion., (Copyright © 2021 Elsevier B.V. All rights reserved.)

This study aims to better understand the effects of heavy metal enrichment on microbiomes and resistomes and the source-specific ecological risks of metals in the sediments of an urban river. Geo-accumulation index and enrichment factor suggested the river sediments were contaminated by Cd, Cu, Pb, and Zn in varying degrees. High-throughput sequencing-based metagenomics analysis identified 430 types of antibiotic resistance genes (ARGs), dominated by the multidrug, MLS, bacitracin, quinolone, and aminoglycoside ARGs, and 52 metal resistance genes (MRGs) mainly conferring resistance to zinc, copper, cadmium, lead, mercury and multiple metals. Spearman correlation analysis and Mantel test showed the heavy metal enrichment exerted significant effects on the microbial community, ARGs and MRGs. Source apportionment using positive matrix factorization revealed that natural source (42.8%) was the largest contributor of metals in the river sediments, followed by urban activities (35.4%) and a mixed source (21.7%). However, when incorporating the apportionment results into a modified risk model to evaluate the source-specific ecological risks, results showed human activities dominated the risks of metals. Comparatively, the urban activities majorly caused moderate- and considerable- ecological risks, while the mixed source with respect to agricultural and industrial activities contributed higher percentages on high- and extremely high- ecological risks., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Recently, crAssphage has been proposed as a human-specific marker for tracking fecal contamination. However, its performance has always been validated in a limited number of host samples, which may obscure our understanding of its utility. Furthermore, few studies have quantified confidence of fecal contamination when using crAssphage . Here, we evaluate the performance and confidence of crAssphage by analyzing a large panel of metagenomic data sets combined with Bayesian analyses. Results demonstrate that crAssphage exhibits superior performance with high host sensitivity and specificity, indicating its suitability for tracking human fecal sources. With the marker, a high confidence (>90%) can be obtained and particularly, multiple samples with positive results provide a near certainty of confidence. The application of crAssphage in the sediments of three Chinese urban rivers shows a high confidence of >97% of human fecal contamination, suggesting the serious challenge of sewage pollution in these environments. Additionally, significant correlation is observed between crAssphage and antibiotic resistance genes (ARGs), expanding the utilization of crAssphage for pollution management of ARGs. This study highlights the benefit of using metagenomic-based analysis for evaluating the performance and confidence of microbial source tracking markers in the coming era of big data with increasing resources in available metagenomic data.

Contaminated sites have been recognized as posing serious comprehensive social and environmental issues and have earned worldwide attention. China is becoming one of the largest contaminated sites remediation markets in the world and the contaminated sites in northeastern China need to rehabilitate urgently. However, remediation planning is often hindered by high financial costs resulting from incomplete assessments of pollution and inappropriate remediation plans. In-depth contaminated site assessments can provide the necessary baseline data for remediation alternatives screening. Therefore, risk assessments and remediation decisions will play crucial roles in the rehabilitation and reconstruction of contaminated sites in China. The main objectives of this study were to present a novel method for health risk assessment (HRA) and to demonstrate a multicriteria decision analysis (MCDA) based on this method to select the most suitable remediation alternatives of groundwater and to prioritize management of contaminated site. To demonstrate the HRA and MCDA processes, a typical contaminated site in Longtan, Jilin province, China, was used. The results of this research indicated that Benzene (PhH) and 1,2-Dichloroethylene (1,2-DCE) were the main organic pollutants and the vanillin plant in the north of the site was main pollution source. Pollution migrated from the north to the south and the health risk range in winter was significantly greater than in summer. Four remediation alternatives were proposed on the basis of the HRA results. The MCDA results showed that PRB was the most suitable technology for integrating the relevant environmental, social, economic, and technical aspects required for remediation. This study may help responsible agencies to strengthen local risk-based program screening frameworks for contaminated sites, to promote reconstruction projects, and to increase local public confidence of contaminated sites remediation., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Surface-water irrigation is one of the most important irrigation methods in areas with abundant surface water. Although this method of irrigation is both economical and convenient, many contaminants are also introduced into the soil-water systems such as organophosphorus pesticides (OPPs). To study the influence of surface-water irrigation on the distribution of OPPs in soil-water systems, 42 water samples (38 groundwater and four surface water) and 85 soil samples (78 profile soil samples and seven topsoil samples) were taken from Shahu in the Jianghan Plain, China. Shahu is a typical Chinese surface-water irrigation district. During sampling, three types of areas were considered: surface-water irrigated areas, groundwater-irrigated areas away from rivers, and non-irrigated areas adjacent to rivers. The results showed that the concentrations of OPPs in the groundwater and soil in the surface-water irrigated farmland were higher than those in groundwater-irrigated farmland. The groundwater flow field and surface-water irrigation were responsible for the OPPs. Thus, it is clear that the surface-water irrigation had a strong influence on the distribution of OPPs in soil-water systems. Principal component analysis for OPPs content in groundwater showed that the key influencing factors on the distribution of OPPs in groundwater were the groundwater flow field and current pesticide use., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The increasing prevalence of antibiotic resistance genes (ARGs) in aquatic environments has attracted considerable concerns due to their potential threat to public health. For reducing environmental risk of ARGs, it is crucial to identify the pathogenic resistant bacteria, determine the driving forces governing the ARG community and apportion their sources, which is yet remained to explore. In this study, we developed a framework integrating high-throughput sequencing (HTS) analyses, null-model-based methods and machine-learning classification tool for understanding the environmental resistome risk and the ecological processes that control the ARG profile in aquatic sediments, and applied to two urban lakes (Lake Tai and Lake Baiyang) in China. The HTS-based metagenomic analyses revealed abundant and diverse resistome, mobilome and virulome in the two lakes, including some emerging ARGs such as mcr and carbapenemases types. Relatively, the diversities for ARGs, mobile genetic elements (MGEs) and virulence factor genes in Lake Baiyang were significantly higher than those in Lake Tai (p < 0.05). The metagenomic assembly and binning approaches tracked a number of potential pathogenic antibiotic resistant bacteria and found the co-occurrence of ARGs, MGEs and human bacterial pathogens in ~50% of the sediment samples, indicating a substantial resistome risk in the lakes. Comparison of multiple-site beta-diversity dissimilarity indexes suggested the ARG diversity was mainly explained by the spatial turnover rather than nestedness and exhibited significant distance-decay pattern. The results of using a novel null-model-based stochasticity ratio showed the stochastic processes made a higher contribution than the deterministic processes on the ARG profile in the environment, especially for Lake Baiyang (>65%). This was confirmed by the determination analyses of various ecological processes on ARG community by utilizing the null-model-based statistical framework for quantifying community assembly. That is, homogenizing dispersal (40%) dominated in Lake Baiyang, followed by homogeneous selection (32%) and ecological drift (15%), while ecological drift (33%) and homogenizing dispersal (31%) were the dominators in Lake Baiyang. SourceTracker analysis showed human sewage-associated sources were the largest contributor (~62%) of ARGs in the environment. The findings shed light on the dissemination risk and driver dynamics of antimicrobial resistance in the aquatic environment, which may help to make effective management strategies for controlling pollution of ARGs., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

As one of the most widespread pollutants worldwide, nitrogen has long been a concern in the environment, including groundwater. However, due to the limitations of investigations and study progress, there is still a poor understanding of groundwater nitrogen pollution and its potential effects on human health in many areas, particularly in developing countries. The spatiotemporal evolution of groundwater nitrate nitrogen levels and potential human health risks in the Songnen Plain, Northeast China were comprehensively studied based on both our own test data and available published data that were collected by us over a study period from 1995 to 2015. Groundwater nitrate nitrogen concentrations exhibited significant temporal and spatial differences: there was an increasing trend with time; and the distribution of high concentration areas expanded from the central and western areas to the east with time. The similar pattern existed in the potential health risks posed to the residents considering the two exposure pathways including drinking water and dermal contact. The effects of groundwater nitrate nitrogen on human health depend on the nitrate concentration but there were also age differences, namely, in the order of infants > children > adult females ≈ adult males, according to the hazard quotient (HQ) used in the human health risk assessment (HHRA) model. The spatiotemporal evolution of groundwater nitrate nitrogen levels and potential human health risks indicate that the issue of nitrogen pollution in groundwater in the study area is worsening and needs further attention. The drivers that increased nitrate nitrogen concentrations in the groundwater of the study area were the increased fertilizer use due to the increased cultivated land area and implementation of a land fertility policy by the local government. It should be acknowledged that the results have uncertainties that not only come from the layout of sampling points and selection of spatial interpolation methods but also come from the parameter settings in the assessment model and assumptions of drinking water scenarios. However, the conclusions still have important reference value for groundwater pollution control and management and human health risk supervision and early warning., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Heterogeneous catalysts for persulfate activation were synthesized using ferrocene and carbon nanofiber as precursor by one-pot hydrothermal method and their performances of catalysts for persulfate activation were evaluated via ibuprofen degradation efficiencies. The structure of the catalyst was identified as carbon encapsulated Fe 3 O 4 grafted on carbon nanofibers (Fe 3 O 4 @C/CNFs) by multiple characterization methods. The CNF supporter could greatly reduce the magnetization of Fe 3 O 4 and increase the coercivity, which effectively avoided agglomeration. The specific surface area of the Fe 3 O 4 @C/CNFs was determined as 65.36 m 2 /g. The Fe 3 O 4 @C/CNFs exhibited high catalytic performances for persulfate activation and ibuprofen could be completely removed in the system with an activation energy of 23.51 kJ/mol. The degradation efficiencies increased with the Fe loading, catalyst dosage and persulfate concentration. The catalysts also showed stable activity with minimal metal leaking over five cycles. Hydroxyl and sulfate radicals were verified by spin-trapping and scavenger experiments and principally contributed to ibuprofen degradation. The possible ibuprofen degradation pathways were elucidated based on intermediate analysis. This work would promote the applications of sulfate radical based advanced oxidation processes for the environmental remediation., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The carbon nanofibers supported Co/Ag bimetallic nanoparticles (Co@CNFs-Ag) were synthesized for heterogeneous activation of peroxymonosulfate and efficient oxidation of amoxicillin in this work. Co nanoparticles with a diameter of 20-30 nm were encapsulated in the carbon nanofibers to reduce the loss of Co during the preparation and catalysis processes. Ag nanoparticles (5-10 nm) were distributed on the surface of CNFs. Complete removal of amoxicillin could be achieved within 30 min by Co@CNFs-Ag activated peroxymonosulfate system. The high catalytic performance could be attributed to the large aspect ratio (> 10,000) of the carbon nanofibers and the mutual reaction of the Co/Ag bimetallic nanoparticles with peroxymonosulfate. The optimal mass ratio of oxidant and catalyst was 10 and the optimized pH was 7. Co@CNFs-Ag exhibited stable catalytic activity and minimal metal leakage over a period of 5 cycles. The activation energy of the system was 29.51 kJ/mol derived by the Arrhenius equation. Both hydroxyl and sulfate radicals contributed to amoxicillin degradation and the latter were key to the degradation. Finally, the reaction mechanism of bimetallic synergistic catalytic system and possible amoxicillin degradation pathways were elucidated. The results of this study provide novel insights for application of sulfate radical-based advanced oxidation processes in environmental remediation., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Bench-scale experiments were conducted to investigate the effect of hydraulic loadings and influent concentration on the migration and biotransformation behavior of three groundwater pollutants: ammonium (NH 4 + ), iron (Fe 2+ ) and manganese (Mn 2+ ). Columns packed with aquifer media collected from a river bank filtration (RBF) site in Harbin City, NE China were introduced synthetic groundwater (SGW) or real groundwater (RGW) were at two different constant flow rates and initial contaminant concentrations to determine the impact of system conditions on the fate of the target pollutants biotransformation. The results showed that the biotransformation rate of Fe 2+ Mn 2+ , and NH 4 + decreased by 8%, 39% and 15% under high flow rate (50 L d -1 ) compared to low flow rate (25 L d -1 ), which was consistent with the residence-time effect. While the biotransformation rate of Fe 2+ Mn 2+ , and NH 4 + decreased by 7%, 14% and 9% under high influent concentration compared to original groundwater. The 16S rRNA analysis of the aquifer media at different depths after experiments completion demonstrated that the relative abundance of major functional microbes iron oxidizing bacteria (IOB) and manganese oxidizing bacteria (MnOB) under higher flow rate and higher influent concentration decreased 13%, 14% and 25%, 24%, respectively, whereas the ammonium oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) exhibited minimal change, compared to the lower flow rate. Above all results indicated that both high flow rate and high concentration inhibit the biotransformation of NH 4 + , Fe 2+ and Mn 2+ . The biotransformation of Fe 2+ and Mn 2+ occurs primarily in the 0-40 cm and 20-60 cm depth intervals, respectively, whereas the NH 4 + biotransformation appears to occur relatively uniformly throughout the whole 110cm column. The biotransformation kinetics of NH 4 + in RGW and SGW, Mn 2+ in RGW at different depths accords with the first order kinetics model, while Fe 2+ in RGW and SGW, Mn 2+ in SGW presented more complicated biotransformation process. The results should improve understanding of the transport and fate of common groundwater pollutants in riverbank filtration and other groundwater recharge environments., Competing Interests: CONFLICT OF INTEREST STATEMENT The authors declare no competing financial interest.

Heavy metal pollution in lakes has attracted concerns worldwide since long retention times in lakes allow metals to accumulate and may pose significant threat to ecosystem health. For designing targeted risk mitigation strategies, it is necessary to identify the source-specific risks of heavy metals in the environment. Although previous studies have addressed either risk assessment or source identification of heavy metals in the environment, few have attempted to establish a link between them. In the study, we perform a combination of source apportionment and risk assessment for characterizing the pollution sources and source-specific risks of heavy metals in the sediments of an urban river-lake system. To this end, positive matrix factorization (PMF) was employed to apportion the potential sources of heavy metals, combined with a support vector machine classifier and the referential source fingerprints of metals in the study area. Then, the apportionment results were incorporated into the environmental risk models to evaluate the ecological and human health risks posed by heavy metals from the identified pollution sources. Results showed the river-lake system was contaminated by Cd, Cu, Zn and other metals in varying degree. Particularly, the element of Cd presented moderate to heavy pollution level. In relative, the industrial activities were identified as the largest contributor (48.0%) of heavy metals in the river-lake sediments, mainly associating with electroplating and paper making, followed by the agricultural activities (27.3%) and mix source (24.7%). Overall, the non-carcinogenic and carcinogenic risks posed by the heavy metals were acceptable, however, the element of Cd showed moderate ecological effect. Further, source-oriented risk evaluation suggested industrial processes made higher contributions to the ecological risk of heavy metals in the river-lake system. The study will provide regulators help to update the information by adding apportionment analysis in the context of risk assessment to facilitate subsequent mitigation strategies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Antibiotics have been widely used in the past decades and caused global public health concerns due to the growing problems of antimicrobial resistance. The peri-urban rivers are always receiving massive wastes containing antibiotics and appear to be a reservoir of antibiotics and antibiotic resistance genes in the environment. To prevent and control the pollution of antibiotics, it is essential to correctly identify the potential sources of antibiotics in peri-urban rivers. Currently, systematic knowledge on risk characteristics and source apportionment of antibiotics in peri-urban rivers is still lacking. In the study, we addressed this problem and focused on exploring the ecotoxicological risk and potential sources of antibiotics in a peri-urban river in Beijing (Chaobai River). To this end, the waters and sediments were collected from the river, as well as the potential source types including domestic sewage, WWTP effluent, chicken manure, pig manure and cattle manure. The occurrence and concentration levels of 16 antibiotics in the waters and sediments of the river were comprehensively characterized, as well as the correlation of antibiotics with environmental factors. Then, risk quotients and mixture risk quotients were used to assess the ecotoxicological risk of single compound and the mixture toxicity of antibiotics, respectively. The synergistic effects of antibiotic mixtures were also analyzed. Further, positive matrix factorization was employed to apportion the potential sources of antibiotics based on the multilinear engine (ME-2) algorithm. The target antibiotics were widely detected in the peri-urban river and several antibiotics posed moderate ecotoxicological risks on aquatic organisms. Apportionment analysis identified four potential sources of antibiotics in the waters of Chaobai River, including domestic sewage (31.5%), chicken waste (26.4%), WWTP effluent (22.2%) and a mix source (20.0%). Additionally, WWTP effluent (~58%) and sewage effluent (41%) were apportioned as the main contributors of antibiotics in the sediments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Solar-induced chlorophyll fluorescence (SIF) is a novel optical signal that has been successfully used to track plant dynamics with the influence of soil water deficit. However, the effect of atmospheric water deficit on SIF under the impact of soil water deficit still remains unclear. Here, continuous measurements of SIF (at 760 nm, F760) of winter wheat under different soil water deficit were collected with a self-developed system. Additionally, soil moisture and atmosphere parameters [including air temperature (Ta), relative air humidity (Rh), and photosynthetically active radiation at 400-700 nm (PAR)] were also synchronously collected by common commercial devices. Vapor pressure deficit (VPD) was calculated based on the measurements of Ta and Rh. The results showed that the driving effect of PAR on F760 was obvious as we expected. Additionally, such effects of PAR on AF760 (F760/PAR) and Fy760 (F760/L685, L685 was canopy radiance at 685 nm) still existed when the PAR influences were partially removed by the calculation of F760/PAR and F760/L685. Furthermore, the relationship of PAR with AF760 or Fy760 was observed to be strengthened under the situation of water deficit through the analysis of Pearson correlations. With the influence of PAR, the accelerative effect of VPD on SIF under soil water deficit was not always observed in our study. Nevertheless, when the effect of PAR was removed by using partial correlation, VPD showed much stronger correlation with SIF in soil water stressed plot than that in unstressed one both at diurnal and seasonal scales. These results revealed that soil water deficit might promote the effect of atmospheric water deficit on SIF. This study has great significance for the application of SIF in drought monitoring and health assessments in terrestrial ecosystem., (Copyright © 2020. Published by Elsevier B.V.)

Bioenergy carbon capture and storage (BECCS) is an effective option for mitigation of greenhouse gas (GHG) emissions. Nevertheless, there is barely serious debate about whether its implementation can possibly jeopardize the global water resources security. Here, we provided an assessment of biomass-based Substitute Natural Gas (BioSNG) production combined with CCS, a promising BECCS technology, in terms of global water resources security, with a focus on the growth of two typical second-generation bioenergy crops: switchgrass and miscanthus. A bottom-up analysis approach was applied in this paper to calculating water consumption for BECCS and estimating water quality deterioration caused by increasing fertilizer and pesticide application. The results indicated that water usage of BECCS was equal to adding 12.86%-16.64% (switchgrass) and 17.59%-26.06% (miscanthus) additional water stress on global available water resources at 2100. Additional N fertilizer application in 2100 would be equal to over 84%, 55% and 42% for both switchgrass and miscanthus under three CCS capture efficiency scenarios, respectively, comparing to such global scale in 2012. Additional phosphate fertilizer adding to global annual available water at 2100 were 0.004-0.008 mg L - 1 (switchgrass) and 0.003-0.006 mg L - 1 (miscanthus), respectively. The secondary environmental hazards, such as N 2 O emission, would offset GHG emission mitigation by BECCS. Meanwhile, the enrichment and leaching of pesticide residues increased the risk of groundwater contamination. This study revealed water consumption and contamination issues caused by BECCS cannot be neglected. Thus, additional studies of accurate land-use models in global scale and advanced technology for biofuel extraction are needed in the future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Apportion soil heavy metal sources across large-scale regions is a challenging task. The present study developed a modified receptor model to estimate the contributions of various sources to soil heavy metals and the associated health risks at a large scale. A positive matrix factorization model based on a partition computing approach was employed; the entire study area was divided into several zones for the source apportionment and then calculated together, termed partition computing-PMF (PC-PMF). The agricultural soil in Tianjin, China, was chosen for the case study. The PC-PMF results showed that irrigation, atmospheric deposition and sludge application were the main anthropogenic sources, with contributions of 26.60 %, 19.56 % and 2.86 %, respectively. We subsequently combined PC-PMF with a human health risk assessment model (HHRA) to obtain the human health risk of every source category. The natural background was regarded as a major factor influencing human health in the study area, with contributions of 38.03 % for the noncarcinogenic risk and 28.68 % for the carcinogenic risk. The results indicated that PC-PMF performed better at the source apportionment of soil heavy metals than PMF. This study provides a good example of how the spatial variability can be utilized to reduce the uncertainty in source apportionment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Water supply safety of riverbank filtration wells (RBFWs) have attracted a great deal of attention in recent years as their role in water supply is increasingly valued. In this study, this issue was revealed from the perspective of water level, quality and supply capacity of RBFWs based on an interference-pumping test with three pumping wells near the Songhua River in Northeast China followed by a recovery test. The results showed that a stable cone of depression of groundwater level in the riverbank filtration (RBF) formed after pumping for about five days with the maximum drawdown of the groundwater level of 10.42 m. The corresponding water capacity of the well group maintained 2.78 × 10 4 m 3 /d from then until the end of the test, 60% of which were captured directly from the river. The groundwater level could return to the level before the pumping test after the pumping test stopped for one day. The RBF could provide turbidity, trace organic substances and major cations and anions (except for Ca 2+ and Mg 2+ ) pre-treatment of the river water with the removal rates of 29%-95% for some water quality indicators. However, limited improvement of water quality was observed with respect to some inorganic contaminants (Fe, Mn and NH 4 + -N) because the background concentrations of them in the groundwater were higher than in the river water. When compared with the impact on water level and supply capacity, the impact of the surface water-groundwater interaction on the mechanisms of water quality evolution was more complicated. Taken together, the results of this study indicate that RBFWs can ensure a sustainable water supply of stable quality, which can also simplify the post-treatment processes of waterworks and reduce costs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Antimicrobial resistance has been a global public health concern. The river-lake systems are one of the tightly connected terrestrial ecosystems and, appear to be reservoirs of antibiotic resistant genes (ARGs) and dispersal routes of resistant pathogens because they are easily impacted by human activities. Currently, systematic knowledge on the prevalence, transfer risk and source of ARGs in river-lake systems is largely lacking. In this study, we focused on the high-throughput profiling and source-sink relationship disentangling of ARGs in the sediments of an interconnected river-lake system (Fuhe River and its receiving Lake Baiyang in northern China). To this end, 40 surface sediments were collected for metagenomic shotgun sequencing. The profile and co-occurrence of ARGs in the sediments of the river-lake system were comprehensively characterized, as well as the mobile genetic elements (MGEs) carrying ARGs and their potential resistome dissemination risk. CrAssphage, a recently-discovered bacteriophage, was used to track human fecal pollution on the prevalence of ARGs. Meanwhile, a novel fast expectation-maximization microbial source tracking (FEAST) method was combined with linear discriminant analysis effect size method (LEfSe) for quantitatively apportioning the contribution of river sediment to the presence of ARGs in the receiving lake. Results showed abundant and diverse ARGs (24 types consisting of 510 subtypes) were detected in the sediments of the river-lake system, including some emerging ARGs such as mcr-1, tetX and carbapenemases types. Network analysis suggested non-random co-occurrence patterns of ARGs within the same type and among different types. Importantly, a number of MGE-carrying contigs were identified with jointly containing one or more ARGs, resulting in higher resistome risk potential in Lake Baiyang than many worldwide lakes. Source tracking indicated the prevalence of ARGs in the sediments of the river-lake system might be largely explained by the extent of human fecal contamination, and apportionment estimates the load transport from Fuhe River contributed more than 80% of ARGs to the receiving Lake Baiyang., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Based on the chemiluminescence (CL) phenomenon of peroxymonosulfate (PMS) and Tb(III) enhanced by its ligand in a micelle microenvironment, a fast and sensitive flow injection CL method for PMS detection was proposed and applied to the analysis of different samples and PMS decomposition. Under the optimized conditions, a linear range was obtained from 4.0 × 10 -6  mol L -1 to 2.0 × 10 -4  mol L -1 with a high correlation coefficient (r = 0.9997), detection limit of 5.0 × 10 -7  mol L -1 (S/N = 3) and relative standard deviation of 2.4% for 1.0 × 10 -5  mol L -1 PMS (n = 9). This was successfully applied to the determination of PMS in Virkon powder, tap water, and swimming pool water samples with satisfactory recoveries from 94.8% to 104.8%. In particular, the analytical frequency could be as fast as five samples per minute because there was no reaction step before analysis and the CL phenomenon was instantaneous. Therefore, this CL method has also been successfully applied to investigate the PMS decomposition profiles in carbon material (carbon nanotubes, carbon nanofibres, activated carbon and graphene oxide) catalysis systems, which followed pseudo-first-order kinetics with good correlation coefficients (r > 0.9305). Quenching experiments and electron spin resonance spectra verified that the CL phenomenon was due to the formation of singlet oxygen, and that hydroxyl and sulfate radicals might be important in the generation of singlet oxygen. Tb(III) is the luminescent emitter according to the characteristics emission bands of the fluorescence and CL spectra in different media., (© 2019 John Wiley & Sons, Ltd.)

Nitrate pollution in groundwater is now one of the most important environmental problems all over the world. For this purpose, a new framework for risk screening and assessment of groundwater nitrate was proposed according to source-pathway-receptor-response model to provide basic for defining environmental management strategies. The framework is composed of groundwater relative risk model (RRM), groundwater contamination risk assessment (CRA), and human health risk assessment (HHRA). The framework is applied in the lower Liaohe river basin plain, northeast of China. The results showed that the priority area with high groundwater relative risk in study area was successfully screened by RRM. Furthermore, the sites with high human health risk for public by groundwater nitrate were selected as hazardous areas. This framework promotes systematic integration of risk assessment of groundwater nitrate and expands traditional research on groundwater management from a scale-based approach to crucial insights into pollution., (Copyright © 2019 Elsevier B.V. All rights reserved.)