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Aquatic environmental assessment of Lake Balaton in the light of physical-chemical water parameters Texte intégral
2017
Sebestyén, Vitkor | Németh, József | Juzsakova, Tatjana | Domokos, Endre | Kovács, Zsófia | Rédey, Ákos
One of the issues of the Hungarian Water Management Strategy is the improvement and upgrading of the water of Lake Balaton. The Water Framework Directive (WFD) specifies and sets forth the achievement of the good ecological status. However, the assessment of the water quality of the lake as a complex system requires a comprehensive monitoring and evaluation procedure. Measurements were carried out around the Lake Balaton at ten different locations/sites and 13 physical-chemical parameters were monitored at each measurement site.For the interpretation of the water chemistry parameters the Aquatic Environmental Assessment (AEA) method devised by authors was used for the water body of the Lake Balaton. The AEA method can be used for all types of the water bodies since it is flexible and using individual weighting procedure for the water chemistry parameters comprehensive information can be obtain. The AEA method was compared with existing EIA methods according to a predefined criterion system and proved to be the most suitable tool for evaluating the environmental impacts in our study.On the basis of the results it can be concluded that the status of the quality of studied area on the Lake Balaton can be categorized as proper quality (from the outcome of the ten measurement sites this conclusion was reached at seven sites).
Afficher plus [+] Moins [-]Analysis of influence mechanism of energy-related carbon emissions in Guangdong: evidence from regional China based on the input-output and structural decomposition analysis Texte intégral
2017
Wang, Changjian | Wang, Fei | Zhang, Xinlin | Deng, Haijun
It is important to analyze the influence mechanism of energy-related carbon emissions from a regional perspective to effectively achieve reductions in energy consumption and carbon emissions in China. Based on the “energy-economy-carbon emissions” hybrid input-output analysis framework, this study conducted structural decomposition analysis (SDA) on carbon emissions influencing factors in Guangdong Province. Systems-based examination of direct and indirect drivers for regional emission is presented. (1) Direct effects analysis of influencing factors indicated that the main driving factors of increasing carbon emissions were economic and population growth. Carbon emission intensity was the main contributing factor restraining carbon emissions growth. (2) Indirect effects analysis of influencing factors showed that international and interprovincial trades significantly affected the total carbon emissions. (3) Analysis of the effects of different final demands on the carbon emissions of industrial sector indicated that the increase in carbon emission arising from international and interprovincial trades is mainly concentrated in energy- and carbon-intensive industries. (4) Guangdong had to compromise a certain amount of carbon emissions during the development of its export-oriented economy because of industry transfer arising from the economic globalization, thereby pointing to the existence of the “carbon leakage” problem. At the same time, interprovincial export and import resulted in Guangdong transferring a part of its carbon emissions to other provinces, thereby leading to the occurrence of “carbon transfer.”
Afficher plus [+] Moins [-]Relationship of meteorological factors and acute stroke events in Kaunas (Lithuania) in 2000–2010 Texte intégral
2017
Tamasauskiene, Laura | Rastenyte, Daiva | Radisauskas, Ricardas | Tamosiunas, Abdonas | Tamasauskas, Domantas | Vaiciulis, Vidmantas | Kranciukaite-Butylkiniene, Daina | Milinaviciene, Egle
Some researchers have hypothesised that meteorological factors may have an impact on acute cerebrovascular diseases. The aim of this study was to determine an impact of some meteorological factors on occurrence of acute cerebrovascular events in the middle-aged Kaunas population. Kaunas stroke register data were used. Data on meteorological factors for the time period from 2000 to 2010 were obtained from the Lithuanian Hydrometeorological Service Kaunas Meteorological Station. We analysed 4038 cases with stroke. Ischemic strokes composed 80.4% and haemorrhagic strokes—19.6%. According to Poisson regression analysis, significant negative correlation between ischemic, haemorrhagic and all types of stroke and ambient air temperature was found (β coefficient − 0.007, −0.016, −0.009, p < 0.001, respectively). Results of ARIMA showed that ambient temperature of the day of stroke onset was associated with the occurrence of ischemic, haemorrhagic and all types of stroke: when temperature was lower, the risk of stroke was higher (−0.006, −0.003, −0.009, p < 0.001, respectively). Low temperature on the event day and 1 and 2 days before the event was associated with higher incidence of haemorrhagic stroke in women. Low ambient temperature on the event day increased incidence of haemorrhagic stroke in subjects 55–64 years. High wind speed on the event day was associated with higher incidence of ischemic stroke in older subjects. Meteorological factors may have some impact on the risk of acute cerebrovascular events. Health care providers should focus on preventive measures, which can reduce these risks.
Afficher plus [+] Moins [-]Study of the antimicrobial and antifouling properties of different oxide surfaces Texte intégral
2017
Blel, W. | Limousy, L. | Dutournié, P. | Ponche, A. | Boucher, A. | Le Fellic, M.
Membrane separation processes find applications in an array of fields as they use far less energy and chemical agents than competing processes. However, a major drawback of membrane technology is that biofilm formation alters membrane performances. Preventing biofilm formation is thus a pivotal challenge for larger-scale development of membrane processes. Here, we studied the comparative antibacterial activities of different inorganic membranes (ceramic and zeolite-coated ceramic with or without copper exchange) using several bacterial strains (Escherichia coli, Staphylococcus aureus, and Bacillus subtilis). In static conditions, alumina plates coated with Cu-exchanged zeolite showed significant bactericidal activity. In dynamic mode (circulation of a contaminated nutrient medium), there was no observable bacterial adhesion at the surface of the Cu-exchanged material. These results confirm the antifouling properties of the Cu-mordenite layer due to both the increased hydrophilicity and antibacterial properties of the active layer.Tests performed with tubular filtration membranes (without copper exchange) showed a significant decline in membrane hydraulic properties during filtration of culture media containing bacteria, whereas copper-exchanged membranes showed no decline in hydraulic permeability. Filtration tests performed with concentrated culture media containing spores of B. subtilis led to a significant decrease in membrane hydraulic permeabilities (but less so with Cu-exchanged membranes). The surfaces showed less effective global antifouling properties during the filtration of a concentrated culture medium due to competition between bacterial growth and the bactericidal effect of copper. Analyses of copper leached in solution show that after a conditioning step, the amount of copper released is negligible.
Afficher plus [+] Moins [-]Concentration-dependent alterations in gene expression induced by cadmium in Solanum lycopersicum Texte intégral
2017
Hou, Jing | Liu, Xinhui | Cui, Baoshan | Bai, Junhong | Wang, Xiangke
Cadmium (Cd) toxicity in agricultural soil has received significant attention because of its higher transformation in the food chain and toxicity to humans. The aim of the present study was to develop sensitive and specific biomarkers for Cd stress. Therefore, transcriptional analyses were performed to investigate concentration-response characteristics of Cd responsive genes identified from a Solanum lycopersicum microarray. The results showed that the lowest observable adverse effect concentrations (LOAECs) of Cd to S. lycopersicum were 1 mg/kg for seed germination, 8 mg/kg for root dry weight, 8 mg/kg for root elongation, and 8 mg/kg for root morphology. Furthermore, the genes were differentially expressed even at the lowest Cd concentrations (0.5 mg/kg), indicating that the detection of Cd in soil at the molecular level is a highly sensitive method. Cd in soil was positively correlated with the expression of the F-box protein PP2-B15 (r = 0.809, p < 0.01) and zinc transporter 4 (r = 0.643, p < 0.01), indicating that these two genes could be selected as indicators of soil Cd contamination.
Afficher plus [+] Moins [-]Intensification of constructed wetlands for land area reduction: a review Texte intégral
2017
Ilyas, Huma | Masih, Ilyas
The large land area requirement of constructed wetlands (CWs) is a major limitation of its application especially in densely populated and mountainous areas. This review paper provides insights on different strategies applied for the reduction of land area including stack design and intensification of CWs with different aeration methods. The impacts of different aeration methods on the performance and land area reduction were extensively and critically evaluated for nine wetland systems under three aeration strategies such as tidal flow (TF), effluent recirculation (ER), and artificial aeration (AA) applied on three types of CWs including vertical flow constructed wetland (VFCW), horizontal flow constructed wetland (HFCW), and hybrid constructed wetland (HCW). The area reduction and pollutant removal efficiency showed substantial variation among different types of CWs and aeration strategies. The ER-VFCW designated the smallest footprint of 1.1 ± 0.5 m² PE⁻¹ (population equivalent) followed by TF-VFCW with the footprint of 2.1 ± 1.8 m² PE⁻¹, and the large footprint was of AA-HFCW (7.8 ± 4.7 m² PE⁻¹). When footprint and removal efficiency both are the major indicators for the selection of wetland type, the best options for practical application could be TF-VFCW, ER-HCW, and AA-HCW. The data and results outlined in this review could be instructive for futures studies and practical applications of CWs for wastewater treatment, especially in land-limited regions.
Afficher plus [+] Moins [-]Selective determination of sulfonamides from environmental water based on magnetic surface molecularly imprinting technology Texte intégral
2017
Xu, Yang | Zhao, Qi | Jiang, Liyan | Li, Zhengqiang | Chen, Yanhua | Ding, Lan
In the study, a simple and selective method based on magnetic separation technology is presented for the extraction of sulfonamides (SAs) from environmental water, followed by liquid chromatography–tandem mass spectrometry. In this method, magnetic surface molecularly imprinted polymers (Fe₃O₄@SiO₂@MIPs) with super-paramagnetic property and high selectivity toward SAs were developed as magnetic adsorbents. The Fe₃O₄@SiO₂@MIPs were then applied to the selective extraction of SAs from environmental water. The extraction and enrichment were accomplished simultaneously in a single step by simply stirring the mixture of adsorbents and water samples. The Fe₃O₄@SiO₂@MIPs were characterized by scanning electron microscopy, Fourier-transform infrared spectrometry, and vibrating sample magnetometry. The adsorption thermodynamics and kinetics were employed to study the adsorption mechanism of the Fe₃O₄@SiO₂@MIPs. And the matrix effect of the method was evaluated. Calibration curves obtained by analyzing matrix-matched standards show excellent linear relationship (R = 0.9994–0.9999) in the concentration range of 10–1000 ng L⁻¹, and the limits of detection are in the range of 1.4–2.8 ng L⁻¹. The relative standard deviations of intra- and inter-day obtained are in the range of 2.8 to 7.8 and 3.1 to 7.9%, respectively. The proposed method was successfully applied to determine SAs in six environmental water samples, and SAs were detectable in four of them with the concentration from 10.5 to 120.2 ng L⁻¹.
Afficher plus [+] Moins [-]Influence of silver nanoparticles and liberated silver ions on nitrifying sludge: ammonia oxidation inhibitory kinetics and mechanism Texte intégral
2017
Giao, Nguyen Thanh | Limpiyakorn, Tawan | Kunapongkiti, Pattaraporn | Thuptimdang, Pumis | Siripattanakul-Ratpukdi, Sumana
Silver nanoparticles (AgNPs) are widely used in commercial products because of their excellent antimicrobial activity. Entrance of AgNPs and its released Ag ions (Ag⁺) into wastewater treatment plants could harm ammonia oxidation (AO) process resulting in environmental problems. This study investigated inhibitory kinetics and mechanism of AO from nitrifying sludge influenced by AgNPs and Ag⁺. The findings demonstrated that AgNPs and Ag⁺ adversely influenced on AO. Silver ions were more toxic to AO than AgNPs, which was indicated by the lower inhibitory constant (K ᵢ) of 0.29 mg/L compared to that of AgNPs (K ᵢ of 73.5 mg/L). Over the experimental period of 60 h, AgNPs at 1, 10, and 100 mg/L released Ag⁺ in the average concentrations of 0.059, 0.171, and 0.503 mg/L, respectively. Silver nanoparticles of 1–100 mg/L inhibited AO by 45–74%, whereas Ag⁺ of 0.05–0.50 mg/L inhibited AO by 53–94%. This suggested that the AgNP toxicity mainly derived from the liberated Ag⁺. Scanning electron microscopy results revealed that AgNPs attached on microbial cell surfaces, and both AgNPs and Ag⁺ induced cell morphological change from rod shape to shorter rod shape. Transmission electron microscopy showed that AgNPs and Ag⁺ diminished the thickness of the outer layer and reduced the density of internal parts of the exposed microbial cells, which could be the reasons for the morphology change. Live/dead results also confirmed that AgNPs and Ag⁺ damaged membrane integrity of cells in the nitrifying sludge. This study suggested that the primary mechanism for toxicity of AgNPs was the liberation of Ag⁺ and then both of silver species caused cell death.
Afficher plus [+] Moins [-]Comparison of the effectiveness of soil heating prior or during in situ chemical oxidation (ISCO) of aged PAH-contaminated soils Texte intégral
2017
Ranc, Bérénice | Faure, Pierre | Croze, Véronique | Lorgeoux, Catherine | Simonnot, Marie-Odile
Thermal treatments prior or during chemical oxidation of aged polycyclic aromatic hydrocarbon (PAH)-contaminated soils have already shown their ability to increase oxidation effectiveness. However, they were never compared on the same soil. Furthermore, oxygenated polycyclic aromatic hydrocarbons (O-PACs), by-products of PAH oxidation which may be more toxic and mobile than the parent PAHs, were very little monitored. In this study, two aged PAH-contaminated soils were heated prior (60 or 90 °C under Ar for 1 week) or during oxidation (60 °C for 1 week) with permanganate and persulfate, and 11 O-PACs were monitored in addition to the 16 US Environmental Protection Agency (US EPA) PAHs. Oxidant doses were based on the stoichiometric oxidant demand of the extractable organic fraction of soils by using organic solvents, which is more representative of the actual contamination than only the 16 US EPA PAHs. Higher temperatures actually resulted in more pollutant degradation. Two treatments were about three times more effective than the others: soil heating to 60 °C during persulfate oxidation and soil preheating to 90 °C followed by permanganate oxidation. The results of this study showed that persulfate effectiveness was largely due to its thermal activation, whereas permanganate was more sensitive to PAH availability than persulfate. The technical feasibility of these two treatments will soon be field-tested in the unsaturated zone of one of the studied aged PAH-contaminated soils.
Afficher plus [+] Moins [-]Chemical properties of dissolved organic matter derived from sugarcane rind and the impacts on copper adsorption onto red soil Texte intégral
2017
Hu, Sihai | Wu, Yaoguo | Yi, Na | Zhang, Shuai | Zhang, Yuanjing | Xin, Xu
Dissolved organic matter (DOM), as the most active organic carbon in the soil, has a coherent affinity with heavy metals from inherent and exogenous sources. Although the important roles of DOM in the adsorption of heavy metals in soil have previously been demonstrated, the heterogeneity and variability of the chemical constitution of DOM impede the investigation of its effects on heavy metal adsorption onto soil under natural conditions. Fresh DOM (FDOM) and degraded DOM (DDOM) from sugarcane rind were prepared, and their chemical properties were measured by Fourier-transform infrared spectrometry (FTIR), excitation-emission matrix (EEM) fluorescence spectroscopes, nuclear magnetic resonance (NMR), and molecular weight distribution (MWD). They were also used in batch experiments to evaluate their effects on the adsorption of Cu(II) onto farmland red soil. Based on our results, the chemical structure and composition of DDOM greatly varied; compared with FDOM, the C/O ratio (from 24.0 to 9.6%) and fluorescence index (FI) (from 1.4 to 1.0) decreased, and high molecular weight (>10 kDa) compounds increased from 23.18 to 70.51%, while low molecular weight (<3 kDa) compounds decreased from 56.13 to 12.13%; aromaticity and humification degree were markedly enhanced. The discrepancy of FDOM and DDOM in terms of chemical properties greatly influenced Cu(II) adsorption onto red soil by affecting DOM-Cu(II) complex capacity. The FDOM inhibited the adsorption of Cu(II), while DDOM promoted adsorption, which was significantly influenced by soil pH. Maximum adsorption capacity (Q ₘ) was 0.92 and 5.76 mg g⁻¹ in the presence of FDOM and DDOM, respectively. The adsorption process with DDOM could be better described by the Langmuir model, while that with FDOM was better described by the Freundlich model. The impacts caused by the dynamic changes of the chemical properties of DOM under natural conditions should therefore be considered in the risk assessment and remediation of soils contaminated with heavy metals.
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