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As an indispensable type of pesticide, fungicides have been somewhat neglected compared to insecticides and herbicides. Heavy fungicide application in agricultural regions may generate downstream ecological concerns via in-stream transport, and the reservoir complicates the process. Monitoring fungicide exposure and exploring reservoir effect on fungicide transport is the key to develop the downstream strategies of agricultural diffusion pollution control. Here, we investigated the exposure, spatiotemporal dynamics, and ecological risk of fungicides in a reservoir-regulated agricultural basin, located in the middle of the Yangtze River Basin, China. Seven fungicides were preliminarily identified and exhibited high detection frequencies (85 %) in subsequent quantification of water samples from three sampling activities. The total concentration of fungicides ranged from 2.47 to 560.29 ng/L, 28.35 to 274.69 ng/L, and 13.61 to 146.968 ng/L in April, September, and November, respectively. Overall, the contamination levels of fungicides were in the ascending order of April November September. The spatial distribution of fungicides was closely associated with the dense of cultivated land, supporting its agricultural source. Furthermore, the reservoir plays a retention role in fungicides, alleviating ecological pressure downstream during the water storage period. Yet, due to the alternation of "source" and "sink" function of the reservoir, the contribution of Zijiang River to the fungicide load in the Yangtze River Basin still needs further attention. Although there is no acute risk posed by fungicides, even in the high-exposure scenario, the chronic ecological risk could not be ignored. Agricultural intensive regions, coupled with the reservoir, provide rather substantial chronic ecological concerns. Carbendazim has been designated as a priority pollutant that contributes significantly to cumulative chronic risk. Thus, we emphasize strengthening the supervision of fungicides in surface water and rationally restricting the use of carbendazim in agricultural operations.

Estuarine heavy metal deposition processes in tributaries can reflect the environmental changes in the basin and the contribution of tributaries to the pollution of downstream lakes. The dynamic processes of heavy metal deposition in two major tributaries of the middle reaches of the Yangtze River were explored using sediment cores. The relationships between heavy metals (HMs) and various physicochemical properties were analyzed using Pearson correlation analysis. The sediment chronological sequences were determined using Pb isotope dating, and the sediment fluxes of heavy metals were calculated. The differences in the driving factors of the two watersheds were analyzed using redundancy analysis. The results showed that heavy metal in both sediment cores were significantly higher than the corresponding background values and showed a relatively stable trend from deep to shallow, with Cd being the most exceeded heavy metal in both tributaries. The average sediment deposition rate was 1.31 cm/year. The Pearson correlation analysis (PCA) results between the HMs indicated similar sources, and the correlation analysis between HM and environmental variables showed that the HMs in both cores, especially Cu and Cr, were significantly correlated with phosphorus, suggesting a synergistic loss of HMs and P. Heavy metal deposition and the normalized difference vegetation index (NDVI) in watersheds showed a negative correlation. This negative correlation is more pronounced in watersheds with higher vegetation cover, where heavy metal deposition is more driven by natural factors. The redundancy analysis (RDA) results indicated that the transport of Cd and Cu was influenced by precipitation and runoff. Heavy metal deposition processes in lake estuaries under improved terrestrial vegetation show the historical contribution of tributaries to lakes, which is important for studying pollution and ecological restoration in watersheds.

Herbicides are ubiquitous pollutants in estuaries because of the increased demand for food and the need for intensive agricultural systems worldwide. Multi-interface partitioning processes are inadequate for the degradation products of herbicides, especially in sediment-laden river estuaries with intensive water and sediment partitioning. Therefore, the partition characteristics of atrazine and its degradation products at the surface water-suspended particulate matter (SPM), surface water-surface sediment, and SPM-surface sediment interfaces in a typical sediment-laden river estuary were analyzed, the dominant environmental factors were described, and the related mechanisms were explored. The results showed that the partitioning priority of atrazine and its degradation products was surface water SPM surface sediment. The partition coefficients of these three interfaces were significantly correlated. The primary degradation products and desisopropylhydroxyatrazine tended to partition into the SPM, and desethyldesisopropylatrazine tended to partition into the surface sediment. Canonical analysis and structural equation modeling indicated that temperature, salinity, sediment pH, and SPM concentrations were the main influencing factors. In the sediment-laden river estuary, the SPM concentration was the most dominant factor. The partition coefficients increased exponentially when the SPM concentration was150 mg/L at the SPM-surface sediment interface, leading to a rapid shift in the interface proportion of atrazine and its degradation products. In the context of climate change and human activities, the SPM concentration in the estuary was decreasing, which hastened the release potential for atrazine and its degradation products from the estuarine sediment. The investigation of the partition traits of organic degradation pollutants promotes the understanding of the multi-interface transport processes in estuaries.

Under the environmental changes associated with mine tributaries entering mainstream rivers, differences in the distributions and migration behaviors of metal(loid)s can be found, but the behavior of antimony (Sb) is still poorly understood in this regard. We analyzed the occurrence, distribution, migration, and influencing factors of the Sb concentration in the water body of the Zijiang River (ZR) around a superlarge Sb deposit zone. The total Sb concentrations were 1.45-15.66 μg/L, 3.16-133.63 mg/kg, and 0.83-41.82 μg/L in the ZR surface waters, sediments, and pore waters, respectively; Sb(V) was the predominant form of Sb found in the surface waters. Mining and smelting were the main sources of Sb in the ZR. Spatially, the Sb concentration showed a decreasing trend from the tributaries to the ZR mainstream. In the ZR, the surface-water Sb concentration showed an increasing trend from the upstream to the downstream, while in the sediments and pore waters, the midstream Sb concentrations were higher than the upstream and downstream concentrations; this finding was related to the sediment retention and accumulation behaviors of reservoirs and dams resulting in the secondary release of Sb in sediments. Sb tended to be bound to the solid phase, dominated by amorphous iron (Fe)/aluminum (Al) oxides and calcium in sediments. This study highlights that, based on current Sb migration patterns, the accumulation of sediments carried by tributaries near Sb mines in the midstream ZR and the Sb pollution caused by sediment release will be long-term, and the related environmental consequences need to be further predicted.

River delta-front estuaries (DEs) are vital interfaces for fluxes between terrestrial and marine environments. However, deep uncertainty exists in estimating the sedimentary pollutant flux from terrestrial environments in DEs due, in part, to a lack of direct measurements in these dynamic and complicated regions and uncertainty in the calculation method. Due to its high sediment content, the Yellow River (YR) has a strong ability to adsorb phosphorus; therefore, it reliably reflects estuarine sedimentary processes. Here, through the comprehensive analysis of field samples, monitoring data and remote sensing images, we conclude that riverine fine particles control the deltaic estuary pollution status and that particle size is the key factor. Based on the stable relationships between phosphorus and heavy metals, with r2 values of 0.990, 0.992, and 0.639 for As, Cd, and Cr, respectively, we estimated that the P flux reached 22.68 g/m2 yr in 2017. Analysis of the YR high-silt sediment load, which has a strong phosphorus adsorption ability and constitutes a substantial fraction of global fluvial sediment transport, revealed a negative correlation between the riverine sediment load and the estuarine phosphorus flux.

In the area affected by non-ferrous metal mining activities, mercury (Hg) contamination in the water and sediments posed potential risks to ecology and human health. In this study, river water and sediment samples were collected in the Zijiang river - South Dongting Lake basin to analyze Hg residues, identify potential Hg sources and evaluate the ecological and health risks posed by Hg contamination. In this study, the average concentrations of THg, PHg, DHg and DMeHg in river water were 38.05 ± 27.13 ng/L, 25.18 ± 26.83 ng/L, 12.88 ± 9.64 ng/L and 0.29 ± 0.07 ng/L, respectively. The THg and MeHg contents in sediments were 234.24 ± 152.93 µg/kg and 0.48 ± 0.16 µg/kg, respectively. The more enrichment of Hg in sediments was observed in the Zijiang River than in the South Dongting Lake, especially in the upstream and midstream regions. Two potential Hg sources in the basin were identified by correlation matrix, principal component analysis (PCA) and positive matrix factorization (PMF) model. The comparable Hg flux with other rivers worldwide was found in the Zijiang River (0.53 Mg/y). Furthermore, it was found by the delayed geochemical hazard (DGH) model that the ecological risk of Hg was more significant in the Zijiang River with more frequent transformation pathways. For different populations, the health risk values caused by Hg were all lower than the USEPA's guideline value. This study provided sound evidence for further control of Hg contamination.

Since the toxicity of Sb(III) is 10 times as high as that of Sb(V) in the environment, it is urgent to find a way to cut down Sb(III). β-FeOOH-modified biochar (β-FeOOH/BC) was prepared and used to remove Sb(III). The characterization results suggested that oxygen-containing functional groups formed on β-FeOOH/BC, which increased the Sb(III) removal efficiency. Even under complex water matrix conditions, the outstanding adsorption performance of β-FeOOH/BC for Sb(III) was obtained. The adsorption reaction rapidly reached a high removal efficiency within 5 min and approached adsorption equilibrium in about 6 h. The adsorption process was fitted to pseudo-second-order kinetics. Amount of maximum adsorption was 202.53 mg g

A pot experiment was conducted to assess the Sb phytoavailability and its accumulation in the wheat before and after remediation, using the composted manure of poultry and sheep, and a chemical amendment (limestone). The present study evaluates the effects of amendments on Sb bioavailability in different soils and investigates the relationship between bioaccumulated Sb and its availability in spiked soils using two different single extraction methods. Furthermore, a sequential extraction procedure was used to measure different fractions of Sb in soil, in order to assess the effect of remediation. The results revealed that bioavailability of Sb were highly affected by the three soil amendments on plant height, uptake of Sb by wheat. Poultry compost (Pc) and Sheep compost (Sc) increased the residual fraction of Sb in soils, and decreased the Sb uptake by wheat, enhanced the height, biomass and dry yield of the wheat crop. While the residual fraction of Sb in soils didn't obviously increased by adding Chemical (limestone) in the four soils. It is concluded that uptake of Sb in the soils significantly decreased with the addition of amended materials in the Sb spiked soils, and poultry compost is the most effective. In the lower level of Sb contaminated soils remediated by poultry compost (Pc), the uptake of Sb in wheat decreased 63.1-74.4 %, 68.7-79.0 %, 68.9-76.9 % and 66.3-82.6 % in S1, S2, S3, S4, compared to the contaminated soils without amendments, respectively.

Globally, organophosphate esters (OPEs) have attracted substantial attention because of their ubiquity in the environment, toxicity, and potential ecological and health risks. This study comprehensively investigated the occurrence, partitioning, and spatial distribution of nine ordinary monomeric OPEs (m-OPEs) and three emerging oligomeric OPEs (o-OPEs) in a major tributary of the middle Yangtze River, which is the Zijiang River (ZR), and their associated potential health risks. Total OPE concentrations ranged from 18.8 to 439 ng L

Mining, smelting and tailing deposition activities can cause metal(loid) contamination in surrounding soils, threatening ecosystems and human health. Microbial indicators are sensitive to environmental factors and have a crucial role in soil ecological risk assessment. Xikuangshan, the largest active antimony (Sb) mine in the world, was taken as the research area. The soil properties, metal(loid) contents and microbial characteristics were investigated and their internal response relationships were explored by multivariate statistical analysis. The assessment of the single pollution index and Nemerow synthetic pollution index (P

Phosphorus is an integral component of marine biogeochemistry. This research investigated the environmental behavior of P in Laizhou Bay using high-resolution sampling, P fractionation, and isotherm adsorption. The total dissolved P (TDP) concentration ranged from 8.4 to 61.0 μg/L in the bay water, while total P (TP) concentration ranged from 311.6 to 654.5 mg/kg in the sediment. The TDP concentration in the water was high in the estuarine area of the Yellow River and the southwestern bay under the combined effects of riverine inputs, direct wastewater discharge, and limited water exchange ability. High TP concentrations in the sediment were observed near the mouth of the Yellow River and central bay, mainly due to the movement and settlement of fine suspended particles under the influence of ocean currents. The P in the bay sediment was predominantly in the calcium-bound fraction and was associated with small particles such as silt and clay. The equilibrium P concentration (EPC

Antimony (Sb) and arsenic (As), carcinogenic and toxic elements, cause environmental pollution, in addition, the different chemical properties of Sb and As make them difficult to co-removal. In this study, we incorporated of nano-TiO

Antimony (Sb) is a hazardous metalloid that is ubiquitous in the environment. Its toxicity and mobility are strongly influenced by the valence state. Particles and aquatic colloids are abundant in ...

Simulating the adsorption behavior of Sb(V) on goethite is of great significance for predicting the mobility of Sb(V) in soil. However, there is still a lack of charge distribution and multisite surface complexation (CD-MUSIC) models that conform to the actual adsorption mechanism. Therefore, our research combined the previous EXAFS results with the SCMs and established two CD-MUSIC models (Model I, which introduced bidentate binuclear and bidentate mononuclear complexes, and Model II, which introduced bidentate mononuclear and monodentate mononuclear complexes). It is also one of the rare cases that bidentate edge- and corner-sharing adsorption complexes have been distinguished by introducing different amounts of H

In this study, surface seawater, bottom seawater and surface sediments were collected from the Yellow River Estuary Area (YREA) and the Laizhou Bay (LB) to investigate the occurrence, spatial distribution and geochemical control factors for total mercury (THg) and methylmercury (MeHg) in different phases. The geochemical characteristics of seawater and sediments suggested significant variances in the YREA and the LB. The high contamination of Hg in the YREA showed the discharge of the Yellow River (YR) contributed significantly to the Hg contamination in the LB. The partial least squares regression (PLSR) model was utilized to explore the complicated interactions between geochemical controls and methylation potentials in different phases. Although the ecological risk (ER) of Hg was not significant in this study area, the higher values of ER in the YREA suggested that the YR was the primary Hg contributor to LB. Therefore, the potential Hg risk should not be ignored.

Currently, alleviating antimony (Sb) contamination in aqueous solutions is crucial for restoring and recovering ecological and environmental health. Due to its toxicity, bioaccumulation and mobile characteristics, developing an efficient technique for antimony decontamination is imperative. Herein, we prepared a Fe-Cu-chitosan (FCC) composite by a one-step coprecipitation method, in which nanoscale Fe/Cu acts as the active sites and the whole structure is exhibited as porous microscale particles. A Fe/Cu proportion of 2/1 (FCC-2/1) was determined to be the optimum proportion for antimony adsorption, specifically 34.5 mg g

Steroid hormones in the environment have attracted public attention because of their high endocrine-disrupting activity even at rather low exposure level. Excessive hormones in the soil from the pollutant discharge of intensive farming would pose a potential threat to the ecology and the human health. Vanadium oxide modified carbon nanotube (VO

Recent studies have suggested that rare earth elements (REEs) are contaminants of emerging concern. Moreover, the understanding of the occurrence and risks of REEs in river-estuary-bay systems is limited. The present study investigated the distributions, geochemical characteristics, and ecological risks of Y and 14 REEs (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) in sediments from the Yellow River to its estuary and adjacent Laizhou Bay. The average total concentrations of Y and REEs in the sediments generally increased from the Yellow River (149 mg/kg) to the estuary (165 mg/kg) and Laizhou Bay (173 mg/kg). In the estuarine core sediments, the concentrations of Y, light REEs (LREEs), and heavy REEs (HREEs) were in the ranges of 19.5-31.4 mg/kg, 58.6-156 mg/kg, and 12.3-19.1 mg/kg, respectively, from the 1700s to 2018, showing no obvious increasing or decreasing trends. The surface and core sediments from the river to the bay were characterized by obvious fractionation between LREEs and HREEs. In sediments, Fe minerals and clay are believed to promote the accumulation of REEs, especially HREEs. The enrichment levels of REEs generally increased from the middle reaches of the Yellow River to the bay, and Gd, Tb, Dy, Ho, Yb, and Lu were the most enriched elements in the sediments. Lu had moderate potential ecological risks in sediments of "the Yellow River-estuary-bay" system, and other REEs had relatively low ecological risks. The potential ecological risk indices of Y and REEs ranged from 78.7 to 144, showing increasing trends from the Yellow River to its estuary and adjacent bay, which should raise concerns regarding emerging contaminant management around estuarine and coastal regions.

Household and personal care products (HPCPs) are a kind of contaminants closely related to daily life, capturing worldwide concern. To our knowledge, this is the first attempt focusing on the spatiotemporal occurrence and mixture risk of HPCPs in the waters from rivers to Laizhou Bay. Nine HPCPs were quantitated in 216 water samples gathered from Laizhou Bay and its adjacent rivers in 2018, 2019, and 2021 to reveal the spatiotemporal occurrence and mixture ecological risks in Laizhou Bay. Eight HPCPs were detected with detection frequencies ranging from 74% to 100%. The total concentrations were in the ranges 105-721 ng L

To investigate the long-term effects of urbanization and industrialization on coastal trace metal contamination, two sediment cores, Q21 (representing 1965-2018) and Q23 (representing 1986-2018), collected from the adjacent coasts of the east old town and west new area of Qingdao were analyzed. Although the concentrations of As, Cd, Co, Cr, Cu, Ni, Pb, Sc, and Zn were higher in Core Q21, the increasing trends in their concentrations and contamination levels were more obvious in Q23, especially since the 2000s. Moreover, the urbanization rates of the new area (1978-2017) were significantly positively correlated with the historical metal concentrations in Q23. Affected by the rapid socio-economic development in the new area, the combined excessive concentrations of the eight metals (excluding Sc) increased faster in Q23 (0.14-78.4 mg/kg) than Q21 (0.58-45.3 mg/kg). Overall, the sediment Core Q23 experienced higher trace metal contamination and ecological risks than Core Q21.

The largest semi-enclosed sea of China, the Bohai Sea, serves as an important sink of microplastics (MPs) originated from terrestrial and marine sources. This study summarized potential sources and migration pathways of MPs in the Bohai Sea and reviewed the abundance and characteristics of MPs in water, sediments, and organisms. Coastal anthropogenic activities (i.e., plastic production, agricultural activities, and industrial and domestic sewage discharge) and marine origins (i.e., aquaculture, marine litters, and transportation) might accelerate the MPs enrichment in the Bohai Sea. The abundance of MPs ranged from 0.07 to 5200 items/m

The removal of arsenic (As(V) and As(III)) from contaminated water has attracted great attention. However, the generation of arsenic-containing hazardous waste by traditional methods has become an inevitable environmental problem. Herein, a UV/sulfite advanced reduction method was proposed to remove As(V) and As(III) from aqueous solution in the form of valuable elemental arsenic (As(0)), thus avoiding the generation of arsenic-containing hazardous waste. The results showed that greater than 99.9% of As(V) and As(III) were reduced to the high purity As(0) (99.5 wt%) with the residual arsenic concentration below 10 μg L

Organic pollutants are ubiquitous in estuarine areas, nonetheless, the transport mechanisms of herbicides in such areas are limited. Atrazine and acetochlor were analyzed in suspended particle matter (SPM), surface sediment, and surface water from the Yellow River estuary and the surrounding rivers and sea. Among these rivers, the Yellow River contributes the most herbicide flux to the sea annually. The herbicide concentrations in water and sediment decreased from the estuarine areas to the deep sea. The fugacity fraction values of atrazine exceeded 0.5 in the Yellow River estuary, which supported that the herbicides in sediment desorbed at the estuarine areas. The herbicide in the SPM showed high concentration in the outer sea and increased as a power function with decreasing SPM content. The increasing partition capacity indicated that the herbicides tended to sink into sediment, increasing the ecological risk posed by herbicides. The ecological risk of acetochlor deserves continuous attention.

Currently, the environmental and ecological damage caused by As(V) and Sb(V) co-contamination has attracted widespread attention worldwide. Due to the similar intrinsic structure configuration and electrostatic repulsion of As(V) and Sb(V), the long-standing issue of their low co-removal capacity remains unresolved. In this study, novel Fe-Cu (FC) binary materials with varied Fe/Cu proportions were synthesized via a simple co-precipitation method to co-eliminate aquatic As(V) and Sb(V). A 2/1 ratio of Fe/Cu was determined to be a suitable proportion with a higher co-adsorption capacity, specifically 70.9 mg·g−1 for As(V) and 94.3 mg·g−1 for Sb(V). Detailed morphological and structural analyses indicated that the FC material gradually changed from microscale aggregates to nanoscale spheres with increasing Cu content, accompanied by an increasing crystalline degree and higher surface area. Additionally, the transformation of amorphous ferrihydrite (FO) into FeO(OH) was suppressed by Fe-Cu complexion during the co-adsorption process, in which ferrihydrite (FO) had more adsorption sites than FeO(OH). In addition, the addition of Cu promoted the pHpzc of FC materials from the acidic range into the neutral or alkaline range. The increased potential difference of FC materials accelerated the As(V) and Sb(V) diffusion rate and effectively offset native electrostatic repulsion, which exhibited a considerable effect than the adsorption sites. Through detailed kinetic data analysis, it was determined that the proportion of the diffusion layer thickness around Sb(V) was suppressed to the As(V) level, and the adsorption kinetics of the two species were both promoted by the self-driven force field. All the results indicated that the co-adsorption capacity depended on the coupling contribution of Fe and Cu, where Fe oxide acted as the major adsorption potential and Cu provided a self-driven force for As(V) and Sb(V) diffusion. This study may provide a novel prospective for homogeneous metal ion co-removal.

China is facing a shortage of antimony (Sb) resources, and Sb emissions are worsening. In exploring solutions to these issues, this paper attempts to apply substance flow analysis (SFA) to track Sb flow among the lithosphere, anthroposphere, and biosphere in China. The results are as follows: (1) China's Sb ore faces the risk of depletion. Although China has the largest Sb reserves in the world, the import of Sb concentrate accounted for a large proportion of the total material input during the production stage, which has increased from 9.78% in 2006 to 30.22% in 2016. Moreover, since 2013, the net export rate of Sb products during the manufacture and fabrication (M&F) stage has been growing, reaching 21.32% in 2016. (2) The Sb industry is highly dependent on ores. Moreover, the resource efficiency and cycling ratio of Sb are quite low. (3) Sb emissions cannot be ignored in industrial processes, particularly Sb emissions from the M&F and usage stages. Sb emissions discharged into the biosphere reached 1915.58 Gg in the period from 2006 to 2016.

Sulfate radical-based advanced oxidation processes (AOPs) have been applied in soil remediation to degrade traditional pollutants in situ, such as polychlorinated biphenyls (PCBs), diesel, polycyclic aromatic hydrocarbons (PAHs), and total petroleum hydrocarbons (TPH). Emerging pollutants such as pesticides, pharmaceuticals, and phthalates have gradually entered the treatment list, and removal technology has been optimized from simple persulfate addition to coupling with various activation methods, including iron activation, thermal activation, base activation, and electrical activation. Peroxydisulfate (PDS) is widely used as oxidant in soil remediation due to its low cost and long environmental retention time. Experimental parameters and some soil properties significantly impact the contaminant removal rate. Changes in soil geochemistry, biology, and contaminant dynamics occur after application of this technology. The degradation rate of contaminants in soil is generally characterized by a pseudo-first-order reaction kinetic model. Other mathematical models have also been developed to understand the oxidation process. This review provides an overview of persulfate-based AOPs for organic contaminated soil remediation, especially for the deep understanding of the activation mechanisms and influential factors.