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Prevalent interactions among marine phytoplankton triggered by long-range climatic stressors are well-known environmental disturbers of community structure. Dynamic response of phytoplankton physiology is likely to come from interspecies interactions rather than direct climatic effect on single species. However, studies on enigmatic interactions among interspecies, which are induced by bioactive extracellular compounds (BECs), especially between related harmful algae sharing similar shellfish toxins, are scarce. Here, we investigated how BECs provoke the interactions between two notorious algae, Alexandrium minutum and Gymnodinium catenatum, which have similar paralytic shellfish toxin (PST) profiles. Using techniques including electron microscopy and transcriptome analysis, marked disruptions in G. catenatum intracellular microenvironment were observed under BECs pressure, encompassing thylakoid membrane deformations, pyrenoid matrix shrinkage and starch sheaths disappearance. In addition, the upregulation of gene clusters responsible for photosystem-I Lhca1/4 and Rubisco were determined, leading to weaken photon captures and CO2 assimilation. The redistribution of lipids and proteins occurred at the subcellular level based on in situ focal plane array FTIR imaging approved the damages. Our findings illuminated an intense but underestimated interspecies interaction triggered by BECs, which is responsible for dysregulating photosynthesis and organelle function in inferior algae and may potentially account for fitness alteration in phytoplankton community.
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Microplastics (MPs) have drawn exponential attention as anthropogenic pollutants, which have invaded every corner of planet. Seamounts are prominent features of the deep-sea topography, acting as breeding ground for marine animal calves and hotspots of pelagic biodiversity, yet MPs pollution in seamounts is scarcely studied. We investigated the MPs load in the whole vertical profile of seamount ambient water in the Subtropical Northwest Pacific Ocean. Based on focal plane array Fourier Transform Infrared spectrometry, MPs were detected in all layers, and varied from 0.9 to 3.8 items L-1, PP and PE were dominant, PA and PET tended to gather at the seamount summit. With depth increasing, small MPs (20-50 µm) were dominant, and MPs surface roughness including crack, hole, and biofouling showed an increase. Three plastic-degrading bacteria were noted in the layers around the seamount, indicating that the seamount community may accelerate MPs aging and further migration. Our work first unveiled the MPs occurrence in the whole vertical profile of the seamount. It reveals that ocean MPs migration and degradation are significantly affected by the unique topography and biotopes of the seamount.
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Monitoramento Ambiental , Microplásticos , Poluentes Químicos da Água , Microplásticos/análise , Oceano Pacífico , Poluentes Químicos da Água/análise , Água do Mar/químicaRESUMO
This paper investigates containment control for fractional-order networked systems. Two novel intermittent sampled position communication protocols, where controllers only need to keep working during communication width of every sampling period under the past sampled position communication of neighbors' agents. Then, some necessary and sufficient conditions are derived to guarantee containment about the differential order, sampling period, communication width, coupling strengths, and networked structure. Taking into account of the delay, a detailed discussion to guarantee containment is given with respect to the delay, sampling period, and communication width. Interestingly, it is discovered that containment control cannot be guaranteed without delay or past sampled position communication under the proposed protocols. Finally, the effectiveness of theoretical results is demonstrated by some numerical simulations.
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Comunicação , Simulação por Computador , Redes Neurais de Computação , AlgoritmosRESUMO
Mercury (Hg) isotopes provide a useful tool to understand Hg sources and processes in the environment. The Hg isotopic composition of seawater remains poorly constrained due to the lack of an efficient method to process large volumes of low-Hg-concentration seawater samples. Here, we develop a continuous flow-double purge and trap device for the in situ preconcentration of Hg in seawater. This method yielded a good Hg recovery of 91.7 ± 3.3% (n = 4, 1SD) for spiked seawater samples and gave reasonably similar Hg isotope ratios of NIST 8610, indicating a limited matrix effect and limited Hg isotope fractionation during processing of seawater. NIST 8610 δ202Hg (-0.55 ± 0.09, n = 4, 1SD) and Δ199Hg (0.07 ± 0.02, n = 4, 1SD) were similar to previously published data. The method was successfully applied to seawater collected from the Xiamen Bay and the South China Sea. The seawater samples showed a Hg recovery of 91.6 ± 5.4% (n = 12, 1SD). Seawater Δ199Hg (-0.04 ± 0.05, n = 7, 1SD) in the Xiamen Bay was different from seawater Δ199Hg (0.05 ± 0.07, n = 5, 1SD) in the South China Sea, which implies distinct Hg sources to coastal and open ocean areas and highlights the robustness of our method in understanding the Hg isotopic composition of seawater.
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Microplastics (MPs) act as carriers for organic pollutants (e.g. antibiotics) and microorganisms (e.g. bacteria) in waters, leading to the proliferation of antibiotic resistance genes. Moreover, the antibiotics adsorbed on MPs may exacerbate this process. For further research, it is necessary to understand the types and amounts of antibiotics adsorbed on MPs. However, due to the heavy work of MPs collection and sample pretreatment, there is a lack of analytical methods and relevant data. In this study, an in-tube solid phase microextraction (IT-SPME) on-line coupled to HPLC-MS/MS method based on amorphous precursor polymer of three-dimensional covalent organic frameworks/monolith-based composite adsorbent was developed, which could efficiently capture, enrich and analyze tetracycline (TCs) antibiotics. Under the optimal extraction parameters, the developed method was capable of detecting TCs at levels as low as 0.48-1.76 pg. This method was applied to analyze the TCs adsorbed on MPs of different particle sizes in mariculture water for the first time, requiring a minimum amount of MPs of only 1 mg. Furthermore, it was observed that there could be an antagonistic relationship between algal biofilm and TCs loaded on MPs. This approach could open up new possibilities for analyzing pollutants on MPs and support deeper research on MPs.
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Microextração em Fase Sólida , Poluentes Químicos da Água , Microextração em Fase Sólida/métodos , Água , Microplásticos , Plásticos , Espectrometria de Massas em Tandem , Espectrometria de Massa com Cromatografia Líquida , Antibacterianos , Poluentes Químicos da Água/análise , TetraciclinasRESUMO
Aqueous zinc-ion batteries (AZIBs) are considered as a promising alternative to lithium-ion batteries for stationary energy storage due to their environmental benignity and cost-effectiveness. However, the development of AZIBs continues to be plagued by a lack of cathode materials with high specific capacity and superior lifetime. Herein, we in-situ synthesize amorphous VO2@rGO assisted by controlling the charging cut-off voltage. Experimental results and theoretical calculations confirm that the amorphous VO2(A)@rGO can effectively reduce the migration energy barrier of Zn2+, improve the conductivity of the electrode, and promote the insertion/extraction of Zn2+. Consequently, the Zn//VO2(A)@rGO battery exhibits an ultra-high specific capacity of 527.0 mAh·g-1 at 1 A·g-1 after 100 cycles, an ultra-long cycle stability of 183.4 mAh·g-1 at 20 A·g-1 after 30,000 cycles, and an energy of 316.1 Wh·Kg-1 at a power density of 6082.9 W·Kg-1 power density. Meanwhile, we reveal that the amorphous VO2@rGO electrode follows a hybrid mechanism of classical Zn2+ insertion/de-insertion and the reversible phase transition from amorphous VO2 to V2O3. This study highlights that in-situ preparation of amorphous VO2@rGO cathode materials by controlling the charging voltage interval, opening up further possibilities for the development of high-performance AZIB cathodes.
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The study analyzes the survey data on the surface sediments in 355 stations in Xiamen Sea area during 2004-2006, 2007-2009, 2010-2013, and 2014-2016. The result finds that contents of TOC, sulfide, and oils in the surface sediments were generally low but showed significant spatial differences (p < 0.05) in most cases, with TOC in the West Sea area (WS) staying significantly higher than other sea areas. Xiamen Sea area suffered universal heavy metal pollution mainly from Cu and Zn for years in the WS, the Jiulong River Estuary (JE), and the East Sea area (ES), and the heavy metal pollution index (HPI) exhibited significant spatial differences across the four periods (p < 0.05). With the source of heavy metals in the WS being mainly related to human activities, Cu and Zn were related to the development of port shipping and Pb to aquaculture. The heavy metal pollution in JE was mainly related to the input of rivers emptying into the sea. The high Cu content in the ES was related to the direct discharge of massive domestic sewage into the sea at the time. From 2004 to 2016, the potential ecological risks of heavy metals in Xiamen Sea area stayed low.
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Metais Pesados , Poluentes Químicos da Água , China , Monitoramento Ambiental , Sedimentos Geológicos , Humanos , Chumbo , Metais Pesados/análise , Óleos , Medição de Risco , Rios , Esgotos , Sulfetos , Poluentes Químicos da Água/análiseRESUMO
Pharmaceuticals and personal care products (PPCPs) in the sea area surrounding a densely populated tourist city in southeastern China were investigated. In total, 32 PPCP pollutants classified into 23 categories were detected. Different spatial distribution patterns of PPCPs indicated possible contamination from runoff and multiple local sources. The labile-to-conservative ratios of PPCPs showed the influence of untreated domestic sewage. In addition, increased concentrations of ciprofloxacin, enrofloxacin, and erythromycin around aquaculture farms imply that aquaculture cannot be neglected as a source. The concentrations of oxytetracycline, ranitidine, ciprofloxacin, miconazole, and sulfamethizole were higher in the wet season than those in the dry season, and the difference in pharmaceutical consumption was suspected to be the main driving factor of this seasonal variation. The risk quotients calculated with the maximum concentrations of miconazole, triclosan, dehydronifedipine, and triclocarban exceeded 0.1, indicating potential moderate or high risks. Antibacterial agents in daily chemicals and azole broad-spectrum antifungals were associated with the highest risks in this study; this might be another significant pollution characteristic in the sea area around this subtropical tourist city.
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Cosméticos , Preparações Farmacêuticas , Poluentes Químicos da Água , China , Cidades , Cosméticos/análise , Monitoramento Ambiental , Medição de Risco , Água do Mar , Poluentes Químicos da Água/análiseRESUMO
In this work, magnetic separably barium ferrite nanomaterial (BaFeO) was synthesized via citrate acid assisted sol-gel combustion method. Subsequently, X-ray diffraction (XRD), scanning electron microscopy-energy dispersion spectroscopy (SEM-EDS), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) were applied for its structural, morphological, and electromagnetic characterization. In addition, microwave (MW) absorption and thermal conversion test results indicated the BaFeO had electrothermal rather than magnetothermal conversion capacity. Meanwhile, the synthesized BaFeO showed satisfactory performance in both eliminating and mineralization of a typical triphenylmethane dye, brilliant green (BG), in MW-induced catalytic oxidation (MICO) process without extra oxidant addition. Besides, changes in element valence and content of BaFeO before and after MICO process investigated with XRD, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) showed its relatively stable properties. Furthermore, transition oxygen species involved in MICO process was deduced as lattice oxygen species. Then, the possible degradation pathway of BG was proposed as demethylation, open-loop of triphenylmethane, releasing one ring, formation of the benzene ring and the ultimate mineralization based on the degradation intermediates tentatively identified by gas chromatography mass spectrometry (GC/MS) and liquid chromatography mass spectrometry (LC/MS), respectively. Finally, ecotoxicity analysis by ecological structure activity relationships (ECOSAR) showed that both the acute and chronic toxicity of these intermediates were lower than that of parent BG. These findings are important regarding the development of efficient catalysts in MICO process for degradation of BG analogues in wastewater.
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Compostos de Bário/química , Compostos Férricos/química , Nanoestruturas/química , Compostos de Amônio Quaternário/química , Catálise , Corantes/química , Magnetismo , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Micro-Ondas , Espectroscopia Fotoeletrônica , Águas Residuárias , Difração de Raios XRESUMO
Microplastic pollution is widespread across most ocean basins around the world. Microplastics (MPs) are small plastic particles that have a significant impact on the marine environment. Various research on plastic pollution have been conducted in several regions. However, currently, there is limited data on the distribution and concentration of MPs in the mid-west Pacific Ocean. Therefore, this study we investigated the abundance, distribution, characteristics, and compositions of MPs in this region. Sea surface water samples collected from 18 stations showed a microplastic concentration range of 6028-95,335 pieces/km2 and a mean concentration of 34,039 ± 25,101 pieces/km2. Highest microplastic concentrations were observed in the seamount region of western Pacific. We observed a significant positive correlation between microplastic abundance and latitude across the study region. It was observed that microplastic concentrations decreased with increasing offshore distance at sites located on a 154° W transect. Fibres/filaments were the dominant microparticles observed in this study (57.4%), followed by fragments (18.3%). The dominant particle size range was 1-2.5 mm (35.1%), followed by 0.5-1 mm (28.5%), and the dominant particle colour was white (33.8%), followed by transparent (31.0%) and green (24.6%). The most common polymer identified by µ-Raman was polypropylene (39.1%), followed by polymethyl methacrylate (16.2%), polyethylene (14.1%) and polyethylene terephthalate (14.2%). The possible sources and pathways of microplastics in the study area were proposed based on the morphological and compositional characteristics of particles, their spatial distribution patterns, and shipboard current profiling (ADCP). Our study contributes to the further understanding of MPs in remote ocean areas.
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Plásticos , Poluentes Químicos da Água/análise , Monitoramento Ambiental , Microplásticos , Oceano PacíficoRESUMO
China is the largest plastic consumer in the world. Despite its plastic waste import ban in 2017, this populous economy inevitably generates a large amount of waste, including plastic waste, a considerable part of which has become marine litter. Data from the 2018 National Coastal Cleanup and Monitoring Project, the largest beach litter monitoring activities using the citizen science approach in China, have been retrieved and analyzed to understand spatial patterns, composition, and original usage of marine litter. Within this project, 24 beaches were surveyed every two months. As a result, the mean density was 3.85 ± 5.39 items m-2, much higher than that reported by previous studies in China. There were great differences in the spatial distribution of litter. The highest densities appeared in the runoff-affected area of the Yangtze River, which was another difference from previous studies. Low-density, easy-to-transport foamed plastics were the major contributor to marine litter in these areas. Along China's coast, approximately 90% of litter was from land-based sources, and over half of that originated from domestic sources. Including foamed plastic products, plastic litter with low recycling value dominated. Both natural and human factors influencing the spatiotemporal distribution and composition of litter are discussed. Socioeconomic factors, such as the lifestyle and consumption levels of citizens and local waste management systems, are possible explanations for the low-value characteristic of marine litter. The deviation between previous data and citizen science data in this study may be caused by many factors. Based on the discussion on these factors, some suggestions for citizen science research in China are also put forward.
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Praias , Monitoramento Ambiental , Resíduos , China , Ciência do Cidadão , PlásticosRESUMO
A novel three-dimensional (3D) flower-like ZnO@Ag composite is successfully synthesized through a simple and facile process, which is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS).When evaluated as an anodic material for nickel-zinc alkaline secondary batteries, the 3D flower-like ZnO@Ag composite exhibits the high discharge capacity (627 mAh g-1) and long cycle life (830 cycles). The outstanding electrochemical performance is ascribed to the Ag nanoparticles enhancing electron conductivity and the uniform flower-like structure providing enough electrochemical reaction sites, so as to reduce electrode polarization and improve cell efficiency. Furthermore, the possible growth mechanism of 3D flower-like ZnO@Ag composite has been proposed. The effect of silver content on formation of ZnO@Ag composites was also investigated in detail, indicating the appropriate silver content plays a key role in forming a defined 3 D flower-like structure for the ZnO@Ag composite.
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Marine debris characterization is fundamental for developing policies aiming at ending the flow of marine debris at the source. China has the largest coastal population in the world. For this emerging economy, the sources of debris might be different from those in regions at different developmental stages. As a typical coastal tourist city and a special economic zone in East China, there are multiple sources of marine debris continuously produced around Xiamen. Marine debris characterization here could provide insights into regulatory measures. Therefore, the abundance and composition of marine debris around Xiamen were investigated. Average densities of floating, beached, benthic macro-debris and floating microplastics (0.5â¯mm - 5â¯mm) were 3963⯱â¯2027â¯itemsâ¯km-2, 0.13⯱â¯0.08â¯itemsâ¯m-2, 20,274⯱â¯15,873â¯itemsâ¯km-2 and 36,455⯱â¯33,935â¯itemsâ¯km-2, respectively. Based on the Clean Coast Indexes, the beaches investigated were supposed to be "very clean" most of the time (73.2%⯱â¯34.9%). Wastes with low value for recycling/reuse, such as grocery bags, ropes, and foams, were the main items of marine debris in the study area. Both domestic sources from the upstream and local fishing/aquaculture activities significantly contributed to marine debris. Obvious regional differences in benthic debris categories could be explained by both natural factors and the rural-urban gap in economic levels, waste-management strategies and infrastructure. These might be common features in this emerging market and densely populated economy. The findings provide insights into the sources of mismanaged waste around this tourist city and some neglected deficiencies in China's current solid waste management system.
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People are increasingly aware of ubiquitous microplastic (MP) pollution in the world's ocean due to its far-reaching harmful impacts on marine ecosystem and potential hazards to human health, yet surprisingly comparatively limited studies about the abundance, source, transport, and fate of MPs in the Northwestern Pacific Ocean are available. We conducted the field survey of MPs pollution at the surface of the Northwestern Pacific Ocean between August 25 and September 26, 2017. MPs were collected from 18 sampling stations in the Northwestern Pacific Ocean using a manta trawl net with a mesh size of â¼330⯵m and a rectangular net opening of 0.45â¯×â¯1â¯m. The abundance, shape, color, size, chemical composition, and surface morphology were characterized using light microscopy, µ-Raman spectroscopy, and scanning electron microscopy (SEM). The results show surface MPs at concentrations ranging over two orders of magnitude (6.4â¯×â¯102 to 4.2â¯×â¯104 particles km-2) and a mean abundance of 1.0â¯×â¯104 particles km-2. The most concentrated MPs were found at XTJ3-9, which may be associated with the convergence of surface currents collectively affected by the Kuroshio and its extension, adjacent eddies, and flow regimes. Polyethylene accounts for 57.8% of enumerated MPs, followed by polypropylene (36.0%) and nylon (3.4%). Pellets, sheets, lines, and films are major forms which may be linked to the breakdown of larger particles, aging processes, and movement over long distances by prevailing currents. Four possible MPs migration pathways were proposed based on the source-specific distribution, chemical fingerprints, size distribution patterns, and the observed physical oceanographic parameters.
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Monitoramento Ambiental/métodos , Poluição Ambiental/análise , Plásticos/efeitos adversos , Oceano Pacífico , Plásticos/química , PrevalênciaRESUMO
Studying the abundance, characteristics, and removal of microplastics (MPs) in wastewater treatment plants (WWTPs) in coastal cities is of great significance for understanding the impacts of human activities on the marine environment, but currently, little information on this topic is available in China. Therefore, the abundance, characteristics, and removal of MPs in seven WWTPs of Xiamen, a typical coastal city in China, are studied. Sixty samples were collected using an improved sampling method involving an electromagnetic flowmeter and a fast digital camera. The influent MPs concentration is 1.57-13.69 items/L, and it is reduced to 0.20-1.73 items/L in the effluent, indicating that 79.3-97.8% MPs is removed. Based on the daily effluent discharge and MPs removal rate, it is estimated that â¼6.5â¯×â¯108â¯MPs are released from the seven WWTPs into the Xiamen Bay each day. The light microscopic and micro-Raman spectroscopic analysis indicates that â¼62.68% of particles are plastic polymers, including polypropylene (31.6%), polyethylene (21.9%), polystyrene (10.1%), propylene/ethylene copolymer (9.2%), and polyethylene terephthalate (7.5%). The color of MPs is mainly composed of white (27.3%) and clears (25.8%). Our results show that granules (41.1%) are the dominant shape of MPs, followed by fragments (31.3%), fibers (23.7%), and pellet (3.9%). The characteristics of MPs such as sizes, shapes, and types affect the MPs removal in WWTPs. Our findings show that MPs concentration in the influent is positively correlated with the suspended solids (SS), however, in the effluent, it is associated with the WWTPs operating load, as reflected by obviously higher MP abundance in overloaded ones.
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Águas Residuárias , Poluentes Químicos da Água , China , Cidades , PlásticosRESUMO
Prevalence of microplastics (MPs) throughout the world's oceans has raised growing concerns due to its detrimental effects on the environment and living organisms. Most recent studies of MPs, however, have focused on the estuaries and coastal regions. There is a lack of study of MPs pollution in the open ocean. In the present study, we conducted field observations to investigate the abundance, spatial distribution, and characteristics (composite, size, color, shape and surface morphology) of MPs at the surface of the Northwestern Pacific Ocean. Samples of MPs were collected at 18 field stations in the Northwestern Pacific Ocean using a surface manta trawl with a mesh size of ~330⯵m and width of 1â¯m from August 25 to September 26, 2017. The MPs were characterized using light microscopy, Micro-Raman spectroscopy, and scanning electron microscopy (SEM). Our field survey results indicate the ubiquity of MPs at all stations with an abundance from 6.4â¯×â¯102â¯itemsâ¯km-2 to 4.2â¯×â¯104â¯itemsâ¯km-2 and an average abundance of 1.0â¯×â¯104â¯itemsâ¯km-2. The Micro-Raman spectroscopic analysis of the MPs samples collected during our field survey indicates that the dominant MPs is polyethylene (57.8%), followed by polypropylene (36.0%) and nylon (3.4%). The individual chemical compositions of MPs from the stations within the latitude range 123-146°E are comparable with each other, with PE being the dominating composition. Similar chemical fingerprints were observed at these field stations, suggesting that the MPs originated from similar sources. In contrast, the major MPs at the field stations adjacent to Japan is polypropylene, which may originate from the nearby land along the coast of Japan. Physical oceanography parameters were also collected at these stations. The spatial distribution of MPs is largely attributed to the combined effects of flow pattern, adjacent ocean circulation eddies, the Kuroshio and Kuroshio Extension system.
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A mass balance of total mercury (HgT, dissolved+particulate) is constructed for China's Jiulong River estuary based on measured HgT concentrations in the surface water, sediment, porewater, and groundwater for May, August, and November 2009, combined with data from the literature. The HgT mass budget results show that the dominant source (39-55%) is desulfurized seawater discharged from the Songyu coal-fired power plant. Submarine groundwater discharge (SGD)-derived HgT flux into the estuary is equivalent to 8-58% of the HgT input from the Jiulong River, which is remarkable when compared with SGD-derived HgT fluxes reported in coastal systems worldwide. Hence, SGD is a significant pathway for the transport of HgT into the Jiulong River estuary. The primary HgT sinks is export to the Taiwan Strait (53-88%), which has important environmental implications on the Hg cycling and marine ecosystems in marginal seas.
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Monitoramento Ambiental/métodos , Estuários , Água Subterrânea/química , Mercúrio/análise , Rios/química , Poluentes Químicos da Água/análise , China , Carvão Mineral/análise , Ecossistema , Centrais Elétricas , Água do Mar/química , Navios , TaiwanRESUMO
The contents of Cu, Pb, Zn, Cd, Cr, Hg and As in the surface sediments of over 668 sites were monitored in a comprehensive program for assessing the degree of heavy-metal pollution and adverse biological effects of the offshore sediments in China. The contamination factor and geoaccumulation index indicated that As and Pb might be two of the most influential pollution loading in these metals. Cluster analysis separated 19 areas in China's near seas into 7 groups with different pollution characteristic, where the sediments along Zhejiang coast were the most highly-contaminated. Based on biological adverse effects index and sediment quality guideline for As, nearly half of sites in China's near seas induced slight adverse biological effects. With correlation analysis, self-organizing map and factor analysis, different sources as well as various adsorption mechanisms/anthropogenic factors were suggested to be important roles in altering the concentration of heavy metals in the sediments.
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Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Metais Pesados/análise , Rios/química , Água do Mar/química , Poluentes Químicos da Água/análise , China , Análise por Conglomerados , Sedimentos Geológicos/análise , Oceanos e Mares , Medição de RiscoRESUMO
To investigate the photodegradation process of dimethyl phthalate (DMP) in the ultraviolet light (UV)-H2O2 system, mass spectrometer was used to identify degradation products and further more, to speculate the possible mechanisms of degradation process. Experimental results showed that the degradation efficiency of 10 mg x L(-1) DMP reached 92.3% in 90 minutes in the UV-H2O2 system, and the more H2O2 was added, the faster DMP decomposed. The pH of DMP solution decreased from the initial 6.5 to 4.98, because of the generating of organic phenolic acids and small acid molecules generated by the degradation of DMP. By the GC/MS as well as LC/MS analysis, degradation products of the DMP in the UV-H2O2 system were thought to comprise six categories, from which we could infer that hydrolysis occurs simultaneously on the two side chains of the DMP, generating phthalic acid that can quickly change to the more stable terephthalic acid. In addition, DMP could also occur benzene ring replacement as well as the ring condensed of the side chains. Finally, by the role of *OH, DMP and its aromatic intermediates occurred ring-opening reaction, and benzene ring was destroyed and generated organic acids of small molecular, which was further mineralized to CO2 and water.
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Poluentes Ambientais/isolamento & purificação , Peróxido de Hidrogênio/química , Ácidos Ftálicos/isolamento & purificação , Raios Ultravioleta , Poluentes Ambientais/química , Espectrometria de Massas , Fotólise/efeitos dos fármacos , Ácidos Ftálicos/químicaRESUMO
Nanoscale copper ferrite was prepared by co-precipitation method, while citrate acid assisted method was used as reference. Microwave-induced degradation of crystal violet was performed with synthesized copper ferrite, and the behavior of copper ferrite in this process was studied by X-ray photoelectron spectroscopy, SEM/EDS and vector network analyzer. Microwave radiation could greatly enhance the activity of copper ferrite in organic oxidation. The variant of copper and iron on the surface and in the inner core of copper ferrite was studied here. Copper ferrite presents relatively low dielectric loss. Meanwhile, microwave radiation makes a faster degradation than conventional heating process, indicating an indispensable non-thermal effect of microwave with copper ferrite in the process. Microwave induced holes could be responsible for the efficient degradation. The effect of annealing on crystallization and degradation process was considered here, and the intermediates and products were studied by GC-MS and LC-MS to provide a comprehensively evaluation of degradation.