Search

Nanoplastics are ubiquitous in marine environments, exhibiting high bioavailability and potential toxicity to marine organisms. However, the impacts of nanoplastics with various surface modifications on marine microalgae remain largely unexplored. This study explored the toxicity mechanisms of two nanoplastic types-polystyrene (PS) and polymethyl methacrylate (PMMA)-with distinct surface modifications on Skeletonema costatum at cellular and molecular levels. Results showed that nanoplastics significantly impaired the growth of microalgae, particularly PS-NH 2 , which caused the most pronounced growth inhibition, reaching 56.99 % after a 96-h exposure at 50 mg/L. Transcriptomic profiling revealed that nanoplastics disrupted the expression of genes predominantly involved in ribosome biogenesis, aminoacyl-tRNA biosynthesis, amino acid metabolism, and carbohydrate metabolism pathways. The integrated biochemical and transcriptomic evidence highlighted that PS-NH 2 nanoplastics had the most adverse impact on microalgae, affecting fundamental pathways such as ribosome biogenesis, energy metabolism, photosynthesis, and oxidative stress. Our findings underscore the influence of surface-modified nanoplastics on algal growth and contribute new understanding to the toxicity mechanisms of these nanoplastics in marine microalgae, offering critical information for assessing the risks of emerging pollutants., 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 © 2024 Elsevier B.V. All rights reserved.)

To explore the occurrence characteristics and health risk levels of the new pollutants organophosphate esters （OPEs） in tap water in Shanghai, based on the water supply areas of the Qingcaosha Reservoir, Chenhang Reservoir, Dongfeng Xisha Reservoir, and Upstream Huangpu River water sources, a total of 52 large shopping malls in Shanghai were selected as tap water sampling sites. Solid phase extraction and gas chromatography-triple quadrupole mass spectrometry were used to determine eight types of OPEs in tap water from shopping malls, including three types of chlorinated OPEs, two types of alkyl OPEs, and three types of aryl OPEs. On this basis, the health risk assessment of the substances with high detection frequency and concentration was carried out. The results showed that six types of OPEs were generally detected, and the average levels of eight types of OPEs in tap water collected in summer and winter were 64.3 ng·L -1 and 60.5 ng·L -1 , respectively. The concentration levels and detection rates of different types of OPEs in tap water followed the order of： chlorinated OPEs > alkyl OPEs > aryl OPEs. From the perspective of water sources, the average concentration of OPEs in tap water with Upstream Huangpu River water sources as the water source was the highest （132 ng·L -1 in summer and 170 ng·L -1 in winter）, and OPEs in tap water with Dongfeng Xisha Reservoir as the water source was the lowest （25.1 ng·L -1 in summer and 6.62 ng·L -1 in winter）. The average concentration of chlorinated OPEs in summer （62.1 ng·L -1 ） was higher than that in winter （53.9 ng·L -1 ）. Based on the reference dose of OPEs, there were no health risks to people of all ages through drinking water exposure. However, the OPE exposure in tap water of Shanghai was higher compared with that of other countries and regions, which requires further attention and research.

In this study, the impact of ammonia nitrogen stress on juvenile four-finger threadfin in pond culture was examined. The 96-hour median lethal concentration (LC50-96h) and safe concentration of ammonia nitrogen were assessed in juveniles with a body weight of 7.4 ± 0.6 g using ecotoxicological methods. The study design included a stress group exposed to LC50-96h levels of ammonia nitrogen and a control group without ammonia nitrogen exposure. To examine the physiological, biochemical, and metabolic effects of ammonia nitrogen on gill tissue, gill tissue samples were collected after 12, 24, 48, and 96 h of stress, with a resumption of treatment after 48 h. Compared to the control group, ammonia nitrogen adversely affected juvenile four-finger threadfin, with LC50-96h and safe concentration values of 20.70 mg/L and 2.07 mg/L, respectively. Exposure to ammonia nitrogen resulted in substantial gill damage, including fusion of lamellae, epithelial cell loss, and proliferation of chlorine-secreting cells. This tissue damage persisted even after a 48-h recovery period. Ammonia nitrogen stress triggered an increase in antioxidant enzyme activity (superoxide dismutase, catalase, and glutathione peroxidase) and malondialdehyde levels in gills, indicating oxidative stress from 12 h onwards. Although enzyme activity decreased over time, oxidative stress persisted even after recovery, suggesting an ongoing need for antioxidant defense. Metabolomics analysis showed significant alterations in 423 metabolites under ammonia nitrogen stress. Key metabolites such as L-arginine, taurine, 20-hydroxyarachidonic acid, 11,12-dihydroxy-5Z, 8Z, and 14Z eicosotrienic acid followed an increasing trend; uridine, adenosine, L-glutathione, and thymidine 5'-triphosphate followed a decreasing trend. These changes reflect metabolic adaptations to stress. In enriched metabolic pathways, the main differential pathways are membrane transport, lipid metabolism, and amino acid metabolism. After 48 h, significant differences were observed in 396 metabolites compared to the control group. Notably, L-arginine, choline, and L-histidine increased, while linoleic acid, adenosine, and glutathione decreased. Amino acid and lipid metabolism pathways were key affected pathways. Under ammonia nitrogen stress, juvenile four-finger threadfin increased the synthesis of unsaturated and saturated fatty acids to cope with low temperatures and bolster immune function by consuming spermidine. This adaptation helps to clear peroxides generated during fatty acid synthesis, thereby protecting cells from oxidative damage. This study provides insights for pond aquaculture and breeding of ammonia nitrogen-tolerant fish strains., 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 © 2024 Elsevier B.V. All rights reserved.)

In recent years, microplastics (MPs) as emerging carriers for environmental pollutants have attracted increasing worldwide attention. However, the adsorption of heavy metals on MPs, especially for biodegradable MPs, has been still poorly understood in estuarine environments. In this study, we investigated the aging of biodegradable and conventional MPs in the Pearl River Estuary after long-term exposure and their impacts on the adsorption of heavy metals from seawater. The results showed that the changes in surface characteristics were more prominent on biodegradable MPs than on conventional MPs after aging. Both biodegradable and conventional MPs could adsorb heavy metals, and their adsorption capacities fluctuated greatly on different MPs and different exposure times. The adsorption capacities of Cu, Pb, and As on biodegradable MPs were higher than those on conventional MPs, whereas Mn, Cr, and Co had lower adsorption on biodegradable MPs after 9-12 months by inductively coupled plasma-mass spectrometry (ICP-MS). The aging characteristics (CI, O/C, and X c ) of MPs accounted for a contribution of 51.0% on heavy metal adsorption, while the environmental factors (temperature, salinity, pH, and heavy metal concentration) only contributed to 13.2%. Therefore, the present study can provide important evidence on the environmental behaviors and ecological risks of biodegradable and conventional MPs in estuarine systems., 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.)

This study reviewed the spatial and temporal distributions of polycyclic aromatic hydrocarbons (PAHs) during 2000-2010 in inland sediments of China and quantified the underlying socioeconomic determinants based on the structural equation model and gravity model. We found that PAHs concentrations in the sediments of eight different regions followed the order of Northern coast>Northeast>Eastern coast>Southern coast>Middle Yellow River>Middle Yangtze River>Southwest>Northwest. The Southern coast, Middle Yangtze River, and Southern coast regions showed large contributions to the high-molecular weight PAHs, whereas the Northeast, Northwest, and Middle Yellow River regions showed high contributions to the low-molecular weight PAHs. PAHs concentrations continuously increased from the year 2000 followed by a gradual decline after 2006, with significant differences in the year when PAHs levels reached their peak. PAHs concentrations of sediment in developed regions declined in recent years following a continuous increase in the 2000s; however, they still increased rapidly in developing regions owing to fast economic development. In addition, the increment rate of PAHs concentrations in sediment at the remote or less-developed regions was slower than that at the developed regions. Urbanization and industrialization had an important effect on PAHs in the sediments, and the largest influencing factor was the economic development.

An effective complex of nanoscale zero-valent iron (NZVI) supported on zirconium 1,4-dicarboxybenzene metals-organic frameworks (UIO-66) with strong oxidation resistance was synthesized (NZVI@UIO-66) for V 5+ removal from wastewater. The results demonstrated that NZVI was successfully loaded on UIO-66 with a uniform dispersion, and then the composite was aged in the air which was named A-NZVI@UIO-66. V 5+ could be removed quickly and completely using A-NZVI@UIO-66 in a wider pH range except for the pH = 1 condition. The reaction between A-NZVI@UIO-66 and V 5+ was an endothermic process. Freundlich model with a better-fitted value showed the adsorption of V 5+ on A-NZVI@UIO-66 was multi-layer heterogeneous adsorption and the adsorbed amount of V 5+ was 397.23 mg V/g NZVI. Nitrate had a competitive inhibition on V 5+ removal by A-NZVI@UIO-66. Mechanisms of vanadium elimination from the aqueous phase by A-NZVI@UIO-66 included physical adsorption, reduction, and complex co-precipitation, particularly the reduction dominated. The subsistent Zr-O bond in A-NZVI@UIO-66 provided a possible double reaction path by playing an electron donor, storage, or conductor role. After acid leaching, A-NZVI@UIO-66 represented good reusability in the removal of V 5+ from the practical mine sewage., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

While expanded polystyrene (EPS) microplastics have been widely recognized as one of the most important components of plastic litter in the intertidal zones of the global ocean, our understanding of their environmental fate on island beaches is insufficient. In this study, we intended to reveal that the latest EPS microplastic pollution status on 5 island beaches in the Pearl River Estuary, China, by comprehensively assessing the abundance, distribution, size, surface texture and carrying capacity of heavy metals (Cd, As, Cr, Ni, Cu, Pb, Mn, Fe, Al). High level of EPS microplastic abundance ranged from 328 to 82,276 particles m -2 was found, with the highest abundance at Guishan Island and the lowest at Dong'ao Island. Spatial distribution of EPS microplastic abundance was significantly different among different islands. EPS microplastics in the size range of 1-2 mm were the most abundant. The content of heavy metals in EPS microplastics collected on the beaches was greater than that in the new EPS products. The average concentrations of heavy metals in EPS microplastics from 5 islands are Cd (0.27 ± 0.19 μg g -1 ), As (5.50 ± 3.84 μg g -1 ), Cr (14.9 ± 8.25 μg g -1 ), Cu (15.0 ± 7.66 μg g -1 ), Ni (17.2 ± 17.6 μg g -1 ), Pb (24.8 ± 7.39 μg g -1 ), Mn (730 ± 797 μg g -1 ), Fe (8340 ± 4760 μg g -1 ), and Al (9624 ± 6187 μg g -1 ), respectively. The correlation between heavy metals in EPS microplastics and sediments was better than that between heavy metals in EPS microplastics and seawater. The study results indicated that EPS microplastics could act as a carrier for the transport of heavy metals, which might pose a threat to biological and human health., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.)

During past two decades, steroid hormones have raised significant public concerns due to their potential adverse effects on the hormonal functions of aquatic organisms and humans. Considering China being a big producer and consumer of steroid hormones, we summarize the current contamination status of steroid hormones in different environmental compartments in China, and preliminarily assess the associated risks to ecological systems. The results show that steroid hormones are ubiquitously present in Chinese surface waters where estrogens are the most studied steroids compared with androgens, progestogens and glucocorticoids. Estrone (E1), 17β-estradiol (17β-E2) and estriol (E3) are generally the dominant steroid estrogens in Chinese surface waters, whereas for the other steroids, androsterone (ADR), epi-androsterone (EADR), progesterone (PGT), cortisol (CRL) and cortisone (CRN) have relatively large contributions. Meanwhile, the investigations for the other environmental media such as particles, sediments, soils and groundwater have been limited, as well as for steroid conjugates and metabolites. The median risk quotients of most steroid hormones in surface waters and sediments are lower than 1, indicating low to moderate risks to local organisms. This review provides a full picture of steroid distribution and ecological risks in China, which may be useful for future monitoring and risk assessment. More studies may focus on the analysis of steroid conjugates, metabolites, solid phase fractions, analytical method development and acute/chronic toxicities in different matrices to pursue a more precise and holistic risk assessment., 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.)

A novel 3D Eu(iii) metal-organic framework (Eu-MOF-1) formulated as [Eu(L)(H2O)(DMA)] (L = 2-(2-nitro-4-carboxylphenyl)terephthalic acid) has been successfully synthesized under solvothermal conditions and characterized by structural analyses. Eu-MOF-1 displays a new 3D framework containing EuIII ions, ligand L, and coordinated DMA molecules and water molecules. The fluorescence investigations indicate that Eu-MOF-1 emits bright red luminescence, and shows relatively high water stability and outstanding chemical stability under a relatively wide range of pH conditions. It is noteworthy that Eu-MOF-1 can quantitatively detect p-aminophenol (PAP) which is a metabolite of phenylamine in human urine. More significantly, Eu-MOF-1 is the first reported multi-responsive luminescent sensor for detecting the biomarker PAP, and MnVII and CrVI anions with high selectivity, sensitivity, recyclability and relatively low detection limits in aqueous solutions. Furthermore, the possible sensing mechanisms of Eu-MOF-1 for selective sensing have also been explored in detail. Eu-MOF-1 could be an ideal candidate as a multi-responsive luminescent sensor in biological and environmental areas.

Nowadays, nanoscale zero valent iron (nZVI) has been extensively applied for the decontamination of various pollutants, but passivation of nZVI severely affects its reactivity in use. In this study, ultrasound (US)-assisted catalytic reduction of Cr(VI) by an acid mine drainage based nZVI (AMD-nZVI) coupling with FeS 2 system was systematically examined. Results show that the presence of FeS 2 and US induced a synergistic enhancement of Cr(VI) removal by AMD-nZVI. Nearly 98% of Cr(VI) removal was achieved by AMD-nZVI/FeS 2 /US process within 60 min under optimal reaction conditions. Several coexisting substances with lower concentration including Pb(II), Ni(II), bisphenol A (BPA) and 2,4-diclorophenol (2,4-DCP) could be effectively removed in simultaneous manner with Cr(VI) removal. The inhibitory order of water matrix species on Cr(VI) removal was NO 3 -  > PO 4 3-  > HCO 3 -  > Ca 2+  > Mg 2+  > Cl - , and a serious suppression effect was induced by humic acid (HA). Addition of ethylene diamine tetra-acetic acid (EDTA) and citric acid (CA) could enhance Cr(VI) removal rate. An enhanced reaction mechanism was proposed, which involved the regeneration of more Fe 2+ and H + by AMD-nZVI/FeS 2 /US process, leading to the reduction of Cr(VI) by AMD-nZVI and FeS 2 into Cr(III) species inculding Cr 2 O 3 and Cr(OH) 3 . This study well demonstrates that AMD-nZVI/FeS 2 /US process is considered as a potential candidate for the remediation of Cr(VI) in real wasterwater., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The applicability of sludge biochar catalyst (SBC) coupling with ultrasound (US) irradiation for the simultaneous removal of Pb(II) and phenol was firstly investigated in this study. Results indicate that Pb(II) removal of SBC/US process was superior to that of SBC without US. The inhibitory order of the coexisting anions on Pb(II) removal was PO 4 3- > HCO 3 -  > NO 3 -  > F - > SO 4 2- > Cl - . Also, several coexisting metals ions inculding Cr(VI), Ni(II) and Cu(II) could be removed in a simultaneous manner with Pb(II). A high removal performance of Pb(II) by SBC/US process and its synergism with phenol oxidation had been successfully achieved. The simultaneous removal efficiencies of Pb(II) and phenol were high up to 95% within 60 min at optimum reaction conditions. Four kinds of Pb species inculding Pb 0 , PbCO 3 , PbO and Pb(OH) 2 were formed during the reaction, whereas five kinds of transformation compounds of phenol such as 1,4-benzoquinone, acetic acid, formic acid, maleic acid and propionic acid were detected. Both HO and O 2 - contributed to the oxidation of phenol by SBC/US process, but HO was dominant radical. A reaction mechanism for the synergistic removal of Pb(II) and phenol by SBC/US process involving in four stages-namely adsorption, precipitation, reduction and Fenton-like oxidation processes was proposed. This study demonstrates that SBC/US process could be considered as a potential candidate for the remediation of real wastewaters containing Pb(II) and phenol., 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 Ltd. All rights reserved.)

Persulfate could be activated by zero-valent iron (ZVI) leading to the rapid removal of various contaminants. However, quick consumption of Fe 2+ largely constrained the removal (%) of target pollutants. Here it was reported that Na 2 S 2 O 8 (SP) combined with ZVI, as an external source of Fe 2+ , was activated by Fe 2+ to quickly (minutes scale) and efficiently (more than 90%) remove As (III) from aqueous solution at an initial pH value from 1.0 to 9.0. As (III) removal was obviously improved by an increase of Fe 2+ rather than Na 2 S 2 O 8 dosage. The removal of As (III) using Fe 2+ -SP-ZVI system followed the pseudo-second-order kinetic and pseudo-first-order kinetic expression. Fe 2+ from ZVI oxidization could improve the efficient generation of , which obviously boosted ZVI corrosion. The production of could be manipulated by oxalic acid, ethylenediaminetetraacetic acid (EDTA), citric acid and phosphates through controlling the concentration of dissociative Fe 2+ , leading to an obvious repression on As (III) removal. The fitting of X-ray absorption fine structure (XAFS) spectra illustrated that the interatomic distance of As-O shell was located between As(III)-O and As(V)-O shell and external Fe 2+ could promote the oxidation of As (III) to As (V) from 35.6% in 1.0 min-44.5% in 10.0 min. Goethite as the main component of iron oxyhydroxides might play a significant role of As (III) adsorption in Fe 2+ -SP-ZVI system. These findings are crucial for knowing the fate and transport of arsenic under permeable reactive barriers., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Recently, clean-up of resistant organic compounds has attracted growing attention. In this study, a novel heterogeneous ultrasound-enhanced sludge biochar catalyst/persulfate (BC/PS/US) process was firstly developed for the degradation of bisphenol A (BPA) in water. The results revealed that BC/PS/US process could successfully achieve a positively synergistic effect between sonochemistry and catalytic chemistry on the degradation of BPA compared to its corresponding comparative process. Nearly 98% of BPA could be degraded within 80 min at optimum reaction conditions. The coexisting substances including Cl - , SO 4 2- and NO 3 - had no obvious inhibition on the BPA degradation, whereas HCO 3 - and humic acid (HA) had significant inhibition effects on that. PS decomposition of BC/PS/US process was superior to that of BC/PS or US/PS process. Both SO 4 - and HO participated in the degradation of BPA, but SO 4 - was predominant radical in the BC/PS/US process. A possible pathway of BPA degradation was proposed, and the BPA molecule was attacked by SO 4 - and degraded into five kinds of intermediate products through hydroxylation and demethylation processes. This study helps to comprehend the application of sludge biochar catalyst as a persulfate activator for the degradation of organic compounds under ultrasound irradiation, and provides a new strategy in wastewater treatment., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In order to acquire the spatial distribution, speciation, and risk assessment of arsenic (As), 18 sediment samples were collected in the middle and upper reaches (Nanpan River, Beipan River, Hongshui River, Diaojiang River, and Duliu River) of the Xijiang River basin, China. The chemical fractions of As in the collected sediments were mainly dominated by the residual fraction and the Fe (Mn, Al) oxide/oxyhydroxides fractions. The correlation analysis results showed that the chemical fraction of As in sediments had close correlations with Mn, good correlations with Fe and organic matter (OM), while weak correlations with Al and carbonate. In addition, it also showed that Diaojiang River basin was found to have an extremely high As pollution status and suffered from high ecological risk. Duliu River and Nanpan River had moderately polluted levels of As and showed a low ecological risk. The other sample sites of Xijiang River basin were uncontaminated of As. The assessment results from this study indicated that the different types of species present based on the chemical fractionation of As from the Xijiang River basin showed different risks. Graphical abstract.

We investigated the concentrations of 10 heavy metals in Potamogeton malaianus , Nymphoides peltata , Eichhornia crassipes , and Hydrilla verticillata to evaluate their potential to bioaccumulate heavy metals and related influencing factors in Taihu Lake. Enrichment factor (EF) values of Cu, Cr, Mn, Ni, Zn, Co, Pb, and V were above 2.0, indicating moderate to significant contamination in sediment. Most of Ti, V, Cr, Mn, and Ni in P. malaianus , E. crassipes , and H. verticillata and V in N. peltata were within excess/toxic level in plants, but higher than normal level. Even though no aquatic plants in this study were identified as a hyperaccumulator, relatively higher concentrations in aquatic plants were found in Taihu Lake than have been found in other previous studies. Heavy metal in submerged plants, especially in their stems, seemed to be more closely related to metals in water and sediment than those in floating-leaf plants. Ratios of metals in stem versus leaves in all plants ranged from 0.2 to 25.8, indicating various accumulation capabilities of plant organs. These findings contribute to the application of submerged aquatic plants to heavy metal removal from moderately contaminated lakes., Competing Interests: The authors declare no conflict of interest.

In this work, a CE method was developed to separate five anthraquinones: aloe-emodin, rhein, emodin, chrysophanol, and physcion. The CE method used a nano-sized metal organic framework MIL-101 (nMIL-101) as pseudostationary phase (PSP) and sorbent for dispersed particle extraction (DPE). The nMIL-101 was synthesized by microwave technique and was characterized by UV-vis, TEM, Zeta potential, X-ray diffraction spectrometry and micropore physisorption. In this method, anthraquinones were adsorbed by nMIL-101 of a fast kinetics within 10 min and then separated by CE. The CE conditions were optimized considering time, pH, buffer ionic strength, and nanoparticles concentration. The optimal CE condition is using 20 mM sodium borate buffer (pH 9.1) containing 15% methanol (v/v) and 400 mg/L nMIL-101 as additives within 8 min. The LODs varied from 24 to 57 μg/L, which were lower than those previously reported. Our method has been successfully applied to determine trace anthraquinones in environmental water samples., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A novel method with high sensitivity for the rapid determination of chrysin, apigenin and luteolin in environment water samples was developed by double-pumps controlled on-line solid-phase extraction (SPE) coupled with high-performance liquid chromatography (HPLC). In the developed technique, metal organic framework MIL-101 was synthesized and applied as a sorbent for SPE. The as-synthesized MIL-101 was characterized by scanning electron microscope, X-ray diffraction spectrometry, thermal gravimetric analysis and micropore physisorption analysis. The MIL-101 behaved as a fast kinetics in the adsorption of chrysin, apigenin and luteolin. On-line SPE of chrysin, apigenin and luteolin was processed by loading a sample solution at a flow rate of 1.0 mL/min for 10 min. The extracted analytes were subsequently eluted into a ZORBAX Bonus-RP analytical column (25 cm long × 4.6 mm i.d.) for HPLC separation under isocratic condition with a mobile phase (MeOH: ACN: 0.02 M H 3 PO 4 = 35:35:30) at a flow rate of 1.0 mL/min. Experimental conditions, including ionic strength, sample pH, sample loading rates, sample loading time and desorption analytes time, were further optimized to obtain efficient preconcentration and high-precision determination of the analytes mentioned above. The method achieved the merits of simplicity, rapidity, sensitivity, wide linear range and high sample throughput. The possible mechanism for the adsorption of flavonoids on MIL-101 was proposed. The developed method has been applied to determine trace chrysin, apigenin and luteolin in a variety of environmental water samples., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

For figuring out the distribution and transportation characteristics of heavy metals Mn, Pb, Cu and As among overlying water-pore water-surface sediments so as to offer a scientific basis for the development of urban construction and protection of karst groundwater, overlying water, pore water and surface sediment samples were collected in December 2013 ( winter) and June 2014 (summer) respectively. Results show that the detection rates of Mn, Pb, Cu and As are 100% both in overlying water and pore water with the concentration Mn > Pb > Cu > As, summer > winter, pore water > overlying water, respectively, and the groundwater could not be a source of drinking water because of the excessive content of Mn and Pb. In addition, the concentration of heavy metals Mn, Pb, Cu and As in pore water are higher than that in overlying water, indicating that heavy metals could diffuse into overlying water from pore water because of concentration gradient, especially in summertime. Moreover, study also finds that heavy metals are accumulated in surface sediments, the total content of four heavy metals has a decreasing trend between UGR6( sampling site 7) and UGR5 (sampling site 6), but has an increasing trend from UGR5 (sampling site 6) to URG0 (sampling site 1). Mn, in surface sediments, has strong instability and mobility, which can not only cause the pollution of overlying water but also enlarge contaminated area. In a word, Laolongdong subterranean river has strong capacity of self-purification, especially the surface sediments.

Even zeolite is promising in ammonia pollution disposing, its removal efficiency is frequently interfered by organics. As activated carbon has good removal efficiency on organic contaminants, combination of two adsorbents may allow their respective adsorption characteristics into full play. This paper provides a performance assessment of the combination for enhancing ammonium removal in micro-polluted raw water. Gel-filtration chromatography (GFC) was carried out to quantify the molecular weight (MW) range of organic contaminants that powdered activated carbon (PAC) and powdered zeolite (PZ) can remove. The polydispersity difference which also calculated from GFC may indicate the wider organic contaminants removal range of PAC and the relatively centralized removal range of PZ. The jar tests of combination dosing confirm a synergistic effect which promotes ammonium removing. Nevertheless, it also shows an antagonism hindering the due removal performance of the two adsorbents on CODMn, while it is not much evident on UV254. Furthermore, a comparison study with simulated coagulation-sedimentation process was conducted to evaluate the optimum dosing points (spatial and temporal) of PAC and PZ among follows: suction well, pipeline mixer, early and middle phase of flocculation. We suggest to dose both two adsorbents into the early phase of flocculation to maximize the versatile removal efficiency on turbidity, ammonium and organic contaminants., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

We report here the first application of the Spatially Referenced Regressions on Watershed Attributes (SPARROW) model to China, a country naturally and culturally distinct from previous SPARROW applications. The Songhuajiang River Basin (556,700 km(2)) empties into the Tongjiang monitoring section, a shared water resource of great import for both Chinese and Russian citizens. The model was calibrated to annual loads of total nitrogen (TN) at 102 sites and total phosphorus (TP) at 65 sites. We assessed the rates of delivery and loss of nutrients from diffuse sources and also provided reach-level predictions of the percentage of nutrient loads delivered from upstream subbasins to Tongjiang monitoring section. The results indicated that farmland and pasture land were responsible for about 70 % of nutrient inputs to the Tongjiang monitoring section. Point source inputs were not statistically significant sources of TN or TP. We presented evidence that rice paddies delivered less TN to streams per area than other types of cropland. The locations responsible for the highest TN and TP inputs to the Tongjiang monitoring section tended to be located near the mainstream, though the areas of highest TN delivered yield did not correspond to the areas of highest TP delivered yield. This suggests that different management priorities may be needed in different parts of the Songhuajiang River Basin.

Salinity has significant effects on nitrification and denitrification processes, particularly in estuarine systems. A dissolved oxygen-enriched river and its estuary in northern China were selected to investigate the impact of salinity gradients (0.6, 4, 7.6, 11.4 and 14.7‰) obtained from the mixing of river samples and estuarine samples with different proportions on coupled nitrification and aerobic denitrification via incubation experiments (35 and 10 °C). Results indicated that: (a) nitrification and coupled nitrification-aerobic denitrification occurred for all treatments, which resulted in NO3- being either accumulated or removed at the end of the incubation; (b) a suitable range of salinity is 4.0-11.4‰ for nitrification and 4.0-7.6‰ for coupled nitrification-aerobic denitrification; and (c) the relatively higher temperature (35 °C) can effectively stimulate N transformation processes compared to the lover temperature (10 °C) in the incubation experiment.

The removal of heavy metals from electroplating wastewater is a matter of paramount importance due to their high toxicity causing major environmental pollution problems. Nanoscale zero-valent iron (NZVI) became more effective to remove heavy metals from electroplating wastewater when enhanced chitosan (CS) beads were introduced as a support material in permeable reactive barriers (PRBs). The removal rate of Cr (VI) decreased with an increase of pH and initial Cr (VI) concentration. However, the removal rates of Cu (II), Cd (II) and Pb (II) increased with an increase of pH while decreased with an increase of their initial concentrations. The initial concentrations of heavy metals showed an effect on their removal sequence. Scanning electron microscope images showed that CS-NZVI beads enhanced by ethylene glycol diglycidyl ether (EGDE) had a loose and porous surface with a nucleus-shell structure. The pore size of the nucleus ranged from 19.2 to 138.6 μm with an average aperture size of around 58.6 μm. The shell showed a tube structure and electroplating wastewaters may reach NZVI through these tubes. X-ray photoelectron spectroscope (XPS) demonstrated that the reduction of Cr (VI) to Cr (III) was complete in less than 2 h. Cu (II) and Pb (II) were removed via predominant reduction and auxiliary adsorption. However, main adsorption and auxiliary reduction worked for the removal of Cd (II). The removal rate of total Cr, Cu (II), Cd (II) and Pb (II) from actual electroplating wastewater was 89.4%, 98.9%, 94.9% and 99.4%, respectively. The findings revealed that EGDE-CS-NZVI-beads PRBs had the capacity to remediate actual electroplating wastewater and may become an effective and promising technology for in situ remediation of heavy metals., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The abandoned mushroom compost of Flammulina velutipes, a cheap and easy by-product to get, was used as biosorbent for removing copper ions from aqueous solution. Batch experiments were carried out to investigate the effect of contact time, solution pH, biomass dosage, initial concentration of Cu2+ ions and temperature on biosorption efficiency. The maximum sorption capacity could be reached at pH 5.0 in 60 min. Langmuir, Freundlich, and Redlich- Peterson isotherm models were used to fit the experimental data and their model parameters were evaluated. The calculated qm based on Langmuir equation was 35.608 mg g(-1) at 288 K, 48.711 mg g(-1) at 298 K, and 42.330 mg g(-1) at 308 K, respectively. The kinetics were discussed by pseudo- first order and pseudo-second order models, and the result showed that the latter was more suitable. The thermodynamics of biosorption was also investigated, and the biosorption process was feasible, spontaneous and endothermic in nature.

Based on field investigations in the Changjiang River mouth, rain sampling from the river's upper reaches to the mouth, historical data, and relevant literatures, the budget and major control factors of total phosphorus (TP) and dissolved inorganic phosphorus (DIP) in the river catchment were estimated and discussed from the catchment scale. It will supply a base for effective controlling P concentration in the Changjiang River and its mouth. Results show that the export fluxes of TP and DIP were mainly controlled by the river runoff. The TP and DIP in the Changjiang River came mainly from agricultural nonpoint source P losses from fertilizer and soil and point sources of industrial waste and residential sewage discharges. The export fluxes of TP and DIP in the river mouth were only 27.0% and 28.3% of the imports from the river catchment, respectively, suggesting that most of P were removed in transportation. A mass of freshwater marshes in the river catchment were the main areas to remove P. Significant increasing in utilization of fertilizer P and incessant increasing in water and soil loss areas were the primary reasons of agricultural nonpoint source P losses. How to decrease the agricultural nonpoint source P loss from the catchment scale is a key controlling P concentration in the Changjiang River and its mouth. The point source industrial waste P discharge has been primarily treated in the river catchment, but the residential sewage P discharge needs further control.

Effect of nanoparticles (Fe and Fe/Ni) on the biodegradation of phenol by BFN at different pH values (8.0, 6.0 and 3.0) was investigated. The results showed that the degradation of phenol was promoted in the presence of the Fe and Fe/Ni nanopracticles at pH = 8.0 and pH = 6.0, whereas only Fe nanoparticles improved the biodegradation of phenol at pH = 3.0. The former could be ascribed to the H2 generated from iron corrosion, which can contribute to the degradation of phenol by BFN and the growth of BFN by providing electrons, while the latter could be attributed to that the increasing pH value resulted from the generation of OH from iron corrosion was beneficial to the growth of BFN. The improved growth of BFN in the presence of the metallic nanopracticles was observed in medium with various pH values. The results obtained from SEM and EDS demonstrated that the nanoparticles were adhered to the surface of BFN, but there was no significant change in the morphology of the microbes. Overall, nanoparticles (Fe and Fe/Ni) can facilitate the growth of BFN and thus the degradation of phenol.

Concentrations of representative organochlorines (OCs), including organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in a batch of farmed mandarin fish from a cultivation pond in Wujiang City, Jiangsu Province, were determined with GC-ECD. Meanwhile, a preliminary human health risk assessment was conducted. Results showed that, the concentrations of dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB) and PCBs in the farmed mandarin fish were in the range of 1.3-4.57 ng/g, 0.13-1.24 ng/g, 0.07-0.44 ng/g and 0-5.22 ng/g, respectively, with an average value of 2.96, 0.40, 1.27 and 0.7 ng/g, respectively. These values were far below the corresponding residue limits set by China's Ministry of Health and the U.S. Food and Drug Administration, and at the low end of the global pollution bar. Referring to the reference values given by USEPA Integrated Risk Information System, calculated non-carcinogenic hazard ratios (HRs) of DDTs, HCB and PCBs were all <1 and carcinogenic HRs of DDTs, HCHs, HCB and PCBs were all >1. The results indicated that DDTs, HCHs and HCB in farmed mandarin fish did not have negative human health influence, but existed potential carcinogenic risk to humans. Compared to rural residents, urban residents were more vulnerable to DDTs, HCHs, HCB and PCBs threats.

Bentonite-supported nanoscale zero-valent iron (B-nZVI) was synthesized using liquid-phase reduction. The orthogonal method was used to evaluate the factors impacting Cr(VI) removal and this showed that the initial concentration of Cr(VI), pH, temperature, and B-nZVI loading were all importance factors. Characterization with scanning electron microscopy (SEM) validated the hypothesis that the presence of bentonite led to a decrease in aggregation of iron nanoparticles and a corresponding increase in the specific surface area (SSA) of the iron particles. B-nZVI with a 50% bentonite mass fraction had a SSA of 39.94 m(2)/g, while the SSA of nZVI and bentonite was 54.04 and 6.03 m(2)/g, respectively. X-ray diffraction (XRD) confirmed the existence of Fe(0) before the reaction and the presence of Fe(II), Fe(III) and Cr(III) after the reaction. Batch experiments revealed that the removal of Cr (VI) using B-nZVI was consistent with pseudo first-order reaction kinetics. Finally, B-nZVI was used to remediate electroplating wastewater with removal efficiencies for Cr, Pb and Cu > 90%. Reuse of B-nZVI after washing with ethylenediaminetetraacetic acid (EDTA) solution was possible but the capacity of B-nZVI for Cr(VI) removal decreased by approximately 70%., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

A Ca-deficient hydroxyapatite (d-HAp) from the by-product of phosphate wastewater treatment has been used to remove fluoride ions. The effects of pH, coexistent calcium and magnesium ions, and chloride ions on the adsorption efficiency were investigated for the system. The results showed that d-HAp adsorbed F- efficiently within a wide pH range (4-7), and the defluoridation capacity of d-HAp remained 85%. There was no significant effect on removal of fluoride ions with addition of up to 200 times as high a concentration of Ca2+, Mg2+ and Cl-, so it suggested that d-HAp was applicable to high fluoride area. The adsorption kinetics can be described by Pseudo-second-order reaction model and the correlation coefficient R2 was 0.999 0. It was also found that the adsorption of F- on d-HAp followed the Langmuir model. The maximal static adsorption capacity was calculated as 26.11 mg x g(-1). It also suggested that ion exchange was the main mechanism during this adsorptive process.

Modified kaolinite clay with 25% (w/w) aluminium sulphate and unmodified kaolin were investigated as adsorbents to remove Pb(II) from aqueous solution. The results show that amount of Pb(II) adsorbed onto modified kaolin (20mg/g) was more than 4.5-fold than that adsorbed onto unmodified kaolin (4.2mg/g) under the optimized condition. In addition, the linear Langmuir and Freundlich models were used to describe equilibrium isotherm. It is observed that the data from both adsorbents fitted well to the Langmuir isotherm. The kinetic adsorption of modified and unmodified kaolinite clay fitted well to the pseudo-second-order model. Furthermore, both modified and unmodified kaolinite clay were characterized by X-ray diffraction, Fourier transform infrared (FT-IR) and scanning electron microscope (SEM). Finally, both modified and unmodified kaolinite clay were used to remove metal ions from real wastewater, and results show that higher amount of Pb(II) (the concentration reduced from 178 to 27.5mg/L) and other metal ions were removed by modified kaolinite clay compared with using unmodified adsorbent (the concentration reduced from 178 to 168 mg/L).

Ipomoea aquatica with low-energy N+ ion implantation was used for the removal of both nitrogen and phosphorus from the eutrophic Chaohu Lake, China. The biomass growth, nitrate reductase and peroxidase activities of the implanted I. aquatica were found to be higher than those of I. aquatica without ion implantation. Higher NO3-N and PO4-P removal efficiencies were obtained for the I. aquatica irradiation at 25 keV, 3.9 x 10(16) N+ ions/cm(2) and 20 keV 5.2 x 10(16) N+ ions/cm(2), respectively (p < 0.05). Moreover, the nitrogen and phosphorus contents in the plant biomass with ion implantation were also greater than those of the controls. I. aquatica with ion implantation was directly responsible for 51-68% N removal and 54-71% P removal in the three experiments. The results further confirm that the ion implantation could enhance the growth potential of I. aquatica in real eutrophic water and increase its nutrient removal efficiency. Thus, the low-energy ion implantation for aquatic plants could be considered as an approach for in situ phytoremediation and bioremediation of eutrophic waters.

The adsorption of humic acid onto hexagonal mesoporous silica(HMS) and surface aminated HMS was investigated. The simulation results using Freundlich model indicated that the surface amination of HMS led to an increase of adsorption constant from 0.56 to 105, reflecting markedly enhanced adsorption of humic acid upon surface amination. In addition, humic acid adsorption under acidic conditions was favored. Adsorbed humic acid molecules were found to be located in the mesopores of aminated HMS and the mesopores with relatively larger pore diameters were preferentially occupied. The kinetics of humic acid adsorption onto the aminated HMS could be well described by second order kinetics and the adsorption rate was mainly dominated by intrapore diffusion process.

The concentrations of Sr and (87)Sr/(86)Sr isotopic ratios have been measured in the dissolved loads from the main channel of the Yangtze River. The result shows that the Yangtze River mainstream water has considerably higher Sr concentration (202-330 microg kg(-1)) and slightly lower (87)Sr/(86)Sr ratio (0.7098-0.7108) than the global average runoff values of dissolved Sr (78 microg kg(-1)) and (87)Sr/(86)Sr ratio (0.7119). The (87)Sr/(86)Sr values of 0.7098-0.7108 in river waters result from the intense weathering of carbonate and evaporate rocks that enriched in the Yangtze River drainage basin. The calculated result based on the end-member mixing model shows that about 91% of total dissolved Sr are derived from the weathering of carbonate and evaporate rocks and the other 9% derived from the weathering of silicate rock. The Yangtze River transports about 1.86 x1 0(11)g yr(-1) (2.12 x 10(9)mol yr(-1)) of dissolved Sr annually to the East China Sea, with an average (87)Sr/(86)Sr of 0.7108. The calculated "(87)Sr(excess) flux" of the Yangtze River is about 2.12 x 10(7)mol yr(-1), indicating the important impact on seawater Sr isotope evolution. The measured (87)Sr/(86)Sr ratios of suspended particulate matters in the Yangtze River water ranging from 0.7178 to 0.7252, are about 0.015 higher than that of corresponding dissolved loads, reflecting more important contribution of silicate particles in suspended particulate matters and preferential dissolution of carbonate rocks during basin weathering.

MnO2 loaded weak basic anion exchange resin D301 (Anion exchange resin, macroreticular weak basic styrene) as adsorbent has been prepared and applied to the removal of cadmium. The adsorption characteristics have been investigated with respect to effect of pH, equilibrium isotherms, removal kinetic data, and interference of the coexisting ions. The results indicated that the Cd2+ could be efficiently removed using MnO2 loaded D301 resin in the pH range of 3-8 from aqueous solutions with the co-existence of high concentration of alkali and alkaline-earth metals ions. T he saturate adsorption capacity of the Cd2+ was 77.88 mg/g. Theadsorption process followed the pseudo first-order kinetics. The equilibrium data obtained in this study accorded excellently with the Langmuir adsorption isotherm.

A new resonance scattering method was proposed for the determination of chlorite, basing on the resonance scattering effect of rhodamine dye. In HCl-sodium acetate buffer solution, chlorite oxidizes I- into I2 and the reaction of I2 and excess I- results in I3- It is respectively combined with rhodamine dyes, including rhodamine B (RhB), butyl rhodamine B (b-RhB), rhodamine G (RhG) and rhodamine S (RhS), to form association complex particles, which exhibit stronger resonance scattering (RS) effect at 400 nm. The chlorite concentration of ClO2- in the range of 0.00726-0.218 microg/ml, 0.0102-0.292 microg/ml, 0.00726 0.145 microg/ml and 0.0290 0.174 microg/ml is respectively linear to the RS intensity of association complex particle systems at 400 nm for the RhB, b-RhB, RhG and RhS. The detection limits of the four systems were respectively 0.00436, 0.00652, 0.00580 and 0.01450 microg/ml ClO2-. In the four systems, the RhB system possesses good stability and high sensitivity. It has been applied to the analysis of chlorite in wastewater with satisfactory results.