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Effects of climate change on surface-water photochemistry: a review
2014
De Laurentiis, Elisa | Minella, Marco | Maurino, Valter | Minero, Claudio | Vione, Davide
Information concerning the link between surface-water photochemistry and climate is presently very scarce as only a few studies have been dedicated to the subject. On the basis of the limited knowledge that is currently available, the present inferences can be made as follows: (1) Warming can cause enhanced leaching of ionic solutes from the catchments to surface waters, including cations and more biologically labile anions such as sulphate. Preferential sulphate biodegradation followed by removal as organic sulphides in sediment could increase alkalinity, favouring the generation of the carbonate radical, CO₃ ·⁻. However, this phenomenon would be easily offset by fluctuations of the dissolved organic carbon (DOC), which is strongly anticorrelated with CO₃ ·⁻. Therefore, obtaining insight into DOC evolution is a key issue in understanding the link between photochemistry and climate. (2) Climate change could exacerbate water scarcity in the dry season in some regions. Fluctuations in the water column could deeply alter photochemistry that is usually favoured in shallower waters. However, the way water is lost would strongly affect the prevailing photoinduced processes. Water outflow without important changes in solute concentration would mostly favour reactions induced by the hydroxyl and carbonate radicals (·OH and CO₃ ·⁻). In contrast, evaporative concentration would enhance reactions mediated by singlet oxygen (¹O₂) and by the triplet states of chromophoric dissolved organic matter (³CDOM*). (3) In a warmer climate, the summer stratification period of lakes would last longer, thereby enhancing photochemical reactions in the epilimnion but at the same time keeping the hypolimnion water in the dark for longer periods.
显示更多 [+] 显示较少 [-]Characterization of the interactions between tetracycline antibiotics and microbial extracellular polymeric substances with spectroscopic approaches
2014
Song, Chao | Sun, Xue-Fei | Xing, Su-Fang | Xia, Peng-Fei | Shi, Yi-Jing | Wang, Shu-Guang
The antibiotics have attracted global attentions for their impact on aquatic ecosystem. The knowledge about the fate of antibiotics encountering extracellular polymeric substances (EPS) is, however, limited. In this study, we investigated the interacting mechanisms of tetracycline (TC) to EPS extracted from aerobic activated sludge. The contributions of the main components of EPS, extracellular proteins, and polysaccharides were evaluated using bovine serum albumin and alginate sodium, respectively. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and nuclear magnetic resonance indicated that hydroxyl, carboxyl, and amino groups were the domain chemical groups involved in the interaction between TC and EPS, and the binding of TC onto EPS changed the structure of these chemical groups, thus causing shifts in their UV–visible absorption spectra. In addition, we found that extracellular proteins, rather than polysaccharides, were the major active contents involved in the interaction. Three-dimensional excitation–emission matrix fluorescence spectroscopy showed that the fluorophores in EPS were clearly quenched by TC and the static quenching process was observed, implying the complex formation of TC and EPS. Furthermore, thermodynamic analysis indicated that the binding of TC with EPS is spontaneous and dominated by electrostatic forces.
显示更多 [+] 显示较少 [-]Carbon dioxide capturing technologies: a review focusing on metal organic framework materials (MOFs)
2014
Sabouni, Rana | Kazemian, Hossein | Rohani, Sohrab
In this study, a relevant literature has been reviewed focusing on the carbon dioxide capture technologies in general, such as amine-based absorption as conventional carbon dioxide capturing technology, aqueous ammonia-based absorption, membranes, and adsorption material (e.g., zeolites, and activated carbons). In more details, metal organic frameworks (MOFs) as new emerging technologies for carbon dioxide adsorption are discussed. The MOFs section is intended to provide a comprehensive overview of MOFs including material characteristics and synthesis, structural features, CO₂adsorption capacity, heat of adsorption and selectivity of CO₂.
显示更多 [+] 显示较少 [-]Aerobic metabolism and cardiac activity in the descendants of zebrafish exposed to pyrolytic polycyclic aromatic hydrocarbons
2014
Lucas, Julie | Perrichon, Prescilla | Nouhaud, Marine | Audras, Alexandre | Leguen, Isabelle | Lefrancois, Christel
The increase of anthropogenic activities on coastal areas induces discharges of polycyclic aromatic hydrocarbons (PAHs) in aquatic ecosystem. PAH effects depend not only on their concentration and the way of contamination but also on the different developmental stages of the organism. Zebrafish were exposed to relevant concentration of pyrolytic PAHs from the first meal (i.e., 5-day post fertilization, dpf) to mature adults. Parental effect of this type of exposure was evaluated through the assessment of aerobic metabolic scope, cardiac frequency, and cardiac mRNA expression on larval and/or embryo progeny of contaminated fish. Our results suggest that cardiac frequency increased in larval descendants of fish exposed to the environmental concentration of pyrolytic PAHs (i.e., 5 ng.g⁻¹of food), while a lack of effect on aerobic metabolism in 5 dpf larvae was highlighted. A surexpression of mRNA related to the cardiac calcium transporting ATPase atp2a2a, a protein essential for contraction, is in accordance with this increasing cardiac frequency. Even if cardiac development genes cmlc1 and tnnt2a were not affected at early life stages tested, complementary work on cardiac structure could be interesting to better understand PAHs action.
显示更多 [+] 显示较少 [-]Responses of the European flounder (Platichthys flesus) to a mixture of PAHs and PCBs in experimental conditions
2014
Dupuy, Célie | Galland, Claire | Devaux, Alain | Bony, Sylvie | Loizeau, Véronique | Danion, Morgane | Pichereau, Vianney | Fournier, Michel | Laroche, Jean
A multibiomarker approach was developed to evaluate the juvenile European flounder responses to a complex mixture of 9 polycyclic aromatic hydrocarbons (PAHs) and 12 polychlorinated biphenyls (PCBs). Exposure was performed through contaminated food pellets displaying: (1) PAH and PCB levels similar to those detected in the heavily polluted Seine estuary, respectively in sediments and in flatfish and (2) ten times these concentrations. Several biomarkers of the immune system (e.g., lysozyme concentration and gene expression of complement component C3 and TNF-receptor), DNA damage (e.g., Comet assay), energetic metabolism (e.g., activity of cytochrome C oxidase), detoxification process (e.g., cytochrome P450 1A1 expression level: CYP1A1; betaine homocysteine methyl transferase expression level: BHMT) were investigated after 14 and 29 days of contamination, followed by a 14-days recovery period. After 29 days of contamination, the detoxification activity (CYP1A1 expression level) was positively correlated with DNA damages; the increase of the BHMT expression level could also be related to the detoxification process. Furthermore, after the recovery period, some biomarkers were still upregulated (i.e., CYP1A1 and BHMT expression levels). The immune system was significantly modulated by the chemical stress at the two concentration levels, and the lysozyme appeared to be the most sensitive marker of the mixture impact.
显示更多 [+] 显示较少 [-]Rhodamine B induces long nucleoplasmic bridges and other nuclear anomalies in Allium cepa root tip cells
2014
Tan, Dehong | Bai, Bing | Jiang, Donghua | Shi, Lin | Cheng, Shunchang | Tao, Dongbing | Ji, Shujuan
The cytogenetic toxicity of rhodamine B on root tip cells of Allium cepa was investigated. A. cepa were cultured in water (negative control), 10 ppm methyl methanesulfonate (positive control), and three concentrations of rhodamine B (200, 100, and 50 ppm) for 7 days. Rhodamine B inhibited mitotic activity; increased nuclear anomalies, including micronuclei, nuclear buds, and bridged nuclei; and induced oxidative stress in A. cepa root tissues. Furthermore, a substantial amount of long nucleoplasmic bridges were entangled together, and some nuclei were simultaneously linked to several other nuclei and to nuclear buds with nucleoplasmic bridges in rhodamine B-treated cells. In conclusion, rhodamine B induced cytogenetic effects in A. cepa root tip cells, which suggests that the A. cepa root is an ideal model system for detecting cellular interactions.
显示更多 [+] 显示较少 [-]Part I: Temporal and spatial distribution of multiclass pesticide residues in lake waters of Northern Greece: application of an optimized SPE-UPLC-MS/MS pretreatment and analytical method
2014
Kalogridi, Eleni-Chrysoula | Christophoridis, Christophoros | Bizani, Erasmia | Drimaropoulou, Garyfallia | Fytianos, Konstantinos
The present work describes the application of an analytical procedure, utilizing ultra performance liquid chromatography (UPLC) coupled with mass spectrometry instrumentation, for the determination of 253 multiclass pesticides, classified in six different groups. Solid phase extraction was applied for the isolation and pre-concentration of target compounds in water samples. Surface waters of the lakes located in Northern Greece (Volvi, Doirani, and Kerkini), were collected in two time periods (fall/winter 2010 and spring/summer 2011) and analyzed, applying the developed analytical methods. Spatial distribution of detected pesticides was visualized using interpolation methods and geographical information systems (GIS). Pesticides with maximum concentrations were amitrole, propoxur, simazine, chlorpyrifos, carbendazim, triazophos, disulfoton-sulfone, pyridaben, sebuthylazine, terbuthylazine, atrazine, atrazine-desethyl, bensulfuron-methyl, metobromuron, metribuzin, rotenone, pyriproxyfen, and rimsulfuron. In Lake Kerkini, mainly carbamates and triazines were determined at elevated concentrations, near the coastal point of the NW side of the lake. Seasonal variations were strong among the applied pesticide classes and determined concentrations, indicating the contribution of pesticide application patterns and rainfall. Lake Doirani exhibited organophosphate pesticides at higher concentrations mainly at coastal points, while triazines emerged as the main pollutant during spring sampling. Lake Volvi exhibited the highest pesticide concentrations, mostly triazines and ureas at the central part of the lake. The occurrence of extreme values and nonconstant seasonal variations indicated that the concentrations were increased disproportionately during the second sampling, as a result of the varying contribution of pollution sources right after the application period. In all cases, the total concentration of pesticides increased during the second sampling period.
显示更多 [+] 显示较少 [-]Effect of water composition on the photocatalytic removal of pesticides with different TiO₂ catalysts
2014
Carbajo, Jaime | García-Muñoz, Patricia | Tolosana-Moranchel, Alvaro | Faraldos, Marisol | Bahamonde, Ana
The objective of this work is double—firstly to explore the photocatalytic efficiency of five different commercial TiO₂ catalysts in the photodegradation of a mixture of pesticides classified by the EU as priority pollutants and secondly to analyze the correlation between their physicochemical properties and the inhibition of the studied photocatalytic process when natural water was employed. Photocatalytic efficiencies when ultrapure water was used seem to point out that surface area was not a prerequisite for the photodegradation of the selected mixture of pesticides. On the other hand, significant differences in total organic carbon (TOC) conversions were obtained with the two studied water compositions. On one side, Evonik materials appear to be mostly inhibited when natural water was employed, whereas on the other, it should be remarked that anatase Sigma-Aldrich (SA) and, particularly, Hombikat UV100 (HBK) materials presented a very limited photo-efficiency inhibition or even a higher initial rate of TOC removal when a natural water matrix was used, probably due to their specific surface properties (PZC, S BET). Therefore, heterogeneous photocatalysis has proved to be a promising technology for the degradation of the selected mixture of pesticides where the final photo-efficiency of the five commercial titania catalysts studied here responds to a complex balance between its surface and structural properties.
显示更多 [+] 显示较少 [-]Degradation of PAHs in soil by Lasiodiplodia theobromae and enhanced benzo[a]pyrene degradation by the addition of Tween-80
2014
Wang, Cuiping | Liu, Haibin | Li, Jing | Sun, Hongwen
Benzo[a]pyrene (BaP), a five-ring polycyclic aromatic hydrocarbon (PAH), which has carcinogenic potency, is highly recalcitrant and resistant to microbial degradation. A novel fungus, Lasiodiplodia theobromae (L. theobromae), which can degrade BaP as a sole carbon source in liquid, was isolated in our laboratory. To prompt the further application of L. theobromae in remediation of sites polluted by BaP and other PAHs, the present study was targeted toward the removal of BaP and PAHs from soil by L. theobromae. The degradation of BaP by L. theobromae was studied using a soil spiked with 50 mg/kg BaP. L. theobromae could remove 32.1 % of the BaP after 35 days of cultivation. Phenanthrene (PHE) inhibited BaP degradation as a competitive substrate. The tested surfactants enhanced BaP degradation in soil by different extents, and a removal rate of 92.1 % was achieved at a Tween-80 (TW-80) concentration of 5 g/kg. It was revealed that TW-80 could not only enhance BaP bioavailability by increasing its aqueous solubility and decreasing the size of its colloid particles but also increase enzyme secretion from L. theobromae and the population of L. theobromae. Moreover, ergosterol content together with the biomass C indicated the increase in L. theobromae biomass during the BaP biodegradation process in soils. Finally, a soil from a historically PAH-contaminated field at Beijing Coking Plant in China was tested to assess the feasibility of applying L. theobromae in the remediation of polluted sites. The total removal rate of PAHs by L. theobromae was 53.3 %, which is 13.1 % higher than that by Phanerochaete chrysosporium (P. chrysosporium), an effective PAH degrader. The addition of TW-80 to the field soil further enhanced PAH degradation to 73.2 %. Hence, L. theobromae is a promising novel strain to be implemented in the remediation of soil polluted by PAHs.
显示更多 [+] 显示较少 [-]Effects of ammonia on methane oxidation in landfill cover materials
2014
Long, Yu-Yang | Liao, Yan | Miao, Jing-Yu | Shen, Dong-Sheng
The effects of ammonia (NH₃) on CH₄attenuation in landfill cover materials consisting of landfill cover soil (LCS) and aged municipal solid waste (AMSW), at different CH₄concentrations, were investigated. The CH₄oxidation capacities of LCS and AMSW were found to be significantly affected by the CH₄concentration. The maximum oxidation rates for LCS and AMSW were obtained at CH₄concentrations of 5 % and 20 %(v/v), respectively, within 20 days. CH₄biological oxidation in AMSW was significantly inhibited by NH₃at low CH₄concentrations (5 %, v/v) but highly stimulated at high levels (20 % and 50 %, v/v). Oxidation in LCS was stimulated by NH₃at all CH₄concentrations due to the higher conversion of the nitrogen in NH₃in AMSW than in LCS. NH₃increases CH₄oxidation in landfill cover materials.
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