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Lost in the North: The first record of Diretmichthys parini (Post and Quéro, 1981) in the northern North Sea
2017
Cresson, Pierre | Rouquette, Manuel | Marco-miralles, Francoise | Dufour, Jean-louis | Causse, Romain | Bouchoucha, Marc | Mahe, Kelig
In June 2015, an individual of Diretmichthys parini (Post and Quero, 1981) was trawled at 530 m depth, in the North Sea off Norway and donated to research. This capture, the first for this species in the North Sea was the northernmost recorded so far, and provided an opportunity to document some aspects of the biology and ecology of this data-poor species. This individual was a female, 331 mm total length of 33 years old, with low mercury content in muscle and liver (~ 0.2 μg g− 1 wet mass). Stable isotope ratios (C and N) in muscle and liver were consistent with the planktonic diet expected for this species. The capture of this fish at the northern latitude known so far would be consistent with the extension of the home range and the latitudinal shift hypothesized for this species in the 1990′s.
显示更多 [+] 显示较少 [-]Response of the pearl oyster Pinctada margaritifera to cadmium and chromium: Identification of molecular biomarkers
2017
Gueguen, Yannick | Saulnier, Denis | Santini, Adrien | Magre, Kevin | Garen, Pierre | Bernagout, Solene | Nohl, Marine | Bouisset, Patrick | Helme, Herehia | Planes, Serge | Le Moullac, Gilles
This study was designed to identify in the pearl oyster Pinctada margaritifera, used as a bio-accumulator, molecular biomarkers for the presence of heavy metals in the lagoon environment. Pearl oysters were exposed to 2 concentrations (1 and 10 μg L− 1) of cadmium (Cd) and chromium (Cr) compared to a control. Twelve target genes encoding proteins potentially involved in the response to heavy metal contamination with antioxidant, detoxification or apoptosis activities were selected. P. margaritifera accumulated Cd but not Cr, and mortality was related to the amount of Cd accumulated in tissues. In response to Cd-Cr contamination, metallothionein (MT) was significantly up-regulated by Cd-Cr at both concentrations, while 7 others (SOD, CAT, GPX, GSTO, GSTM, CASP, MDR) were down-regulated. Based on the development of these molecular tools, we propose that the pearl oyster, P. margaritifera, could be used as a sentinel species for heavy metal contamination in the lagoons of tropical ecosystems.
显示更多 [+] 显示较少 [-]Modeling of real time exhaust emissions of passenger cars under heterogeneous traffic conditions
2017
Jaikumar, Rohit | Shiva Nagendra, S.M. | Sivanandan, R.
This paper presents the characterization and modeling of exhaust emissions released from the passenger cars on urban roads under heterogeneous traffic conditions. Onboard exhaust emissions measurement were made at selected corridors in a populous urban area of India. Exhaust emissions were characterized for different driving modes classified according to vehicle specific power (VSP). Results indicated that emissions at VSP modes under cruising speeds were 10–12 times less than idling (which is the mode used for emission standard certification), braking and accelerating conditions. Also it has been found that more than 20% of time vehicles were in idling conditions at most of the roads.Real-time exhaust emission prediction models for heterogeneous traffic conditions were developed using artificial neural network (ANN) technique. The vehicle characteristics such as revolutions per minute (RPM), speed, acceleration and VSP were used as input to the model. The onboard measurements of CO, HC and NOx concentrations were used to train the ANN based exhaust emission prediction models. Result showed good agreement with onboard measured emissions data (index of agreement = 0.9) of all driving modes. Further, ANN model's emissions were compared with emissions estimated from the COPERT model and emission factors recommended by the Automotive Research Association of India (ARAI). It was found that the ANN model emissions were edge over the ARAI and COPERT model emissions and useful for urban air quality management and traffic planning.
显示更多 [+] 显示较少 [-]Light absorption characteristics of brown carbon during foggy and non-foggy episodes over the Indo-Gangetic Plain
2017
Atmospheric PM1 (particulate matter with aerodynamic diameter ≤ 1 μm) samples have been collected during foggy (n = 17) and non-foggy nights (n = 19) in wintertime at Kanpur in central Indo-Gangetic Plain (IGP) to assess light absorption characteristics and direct radiative forcing of water-extractable brown carbon (BrC). We have observed a significant enhancement (two-tailed t-test: t = 2.2; at significance level: p < 0.05) in the absorption coefficient of water-extractable BrC at 365 nm (babs-BrC-365) from non-foggy (Avg.: 53.5 Mm⁻¹) to foggy episodes (69.3 Mm⁻¹). Enhancement in mass absorption efficiency (MAE) of BrC (1.8 m²/g C) during foggy episodes is consistent with that of babs-BrC-365. Absorption Ångström exponent (AAE) remained similar (2.8) during foggy and non-foggy episodes. Significantly lower value of AAE (2.8) at Kanpur compared to other places in IGP (∼5) highlights more light absorbing potential of atmospheric BrC over central IGP. Furthermore, MAE of EC at 660 nm during foggy period (8.5 m²/g) is relatively high as compared to that during the non-foggy episode (7.0 m²/g). The MAE of BrC and EC exhibited enhancement by ∼15% and 20%, respectively during foggy events. These observations are also reflected by an increase (t = 11.1; p < 0.05) in direct radiative forcing of water-extractable BrC (relative to EC) in the atmosphere: from 23.7 ± 10.8% during non-foggy to 54.3 ± 16.5% during foggy episodes. Differences in chemical composition, loading, absorption properties and direct radiative forcing (DRF) of carbonaceous aerosols during non-foggy and foggy episodes indicate predominant influence of fog-processing.
显示更多 [+] 显示较少 [-]Changes in the diurnal variations of clouds and precipitation induced by anthropogenic aerosols over East China in August 2008
2017
We investigated the impacts of all anthropogenic aerosols and black carbon (BC) on the diurnal variations of cloud and precipitation over East China during August 2008 using a coupled meteorology and chemistry model (WRF-Chem). Comparison of the model results with observations showed that the model reproduced reasonably well the distribution patterns of the aerosol optical depth (AOD), the horizontal wind, precipitation, and the liquid water path (LWP). The results from ensemble numerical experiments showed the aerosol-induced cloud droplet number concentration (CDNC) increased by 20–160 cm⁻³ over East China. The aerosol-induced cloud fraction (CF) increased by 0.03–0.08 below 850 hPa and at around 750 hPa over East China; it decreased by up to 0.06 between 750 and 850 hPa at around 25°N and over Central China. These increases were larger at early morning and nighttime, whereas the decreases were larger in the afternoon and evening. Other scattering aerosols were the main contributor to the increase of CDNC and offset the decrease induced by BC. The decrease of CF over Central China was mainly caused by BC. The precipitation induced by aerosols decreased by 20–200 mm over South and North China with the largest decrease over the North China Plain and southwest China. There was an increase of 20–100 mm over Central China. The decrease in precipitation over South and North China mainly occurred during the day, whereas the increase in precipitation over Central China mainly occurred at night which was caused by BC.
显示更多 [+] 显示较少 [-]Reaction Mechanism and Degradation Pathway of Rhodamine 6G by Photocatalytic Treatment
2017
Rasheed, Tahir | Vēlāyutan̲, T. A. | Iqbal, Hafiz M. N. | Hu, Hongbo | Zhang, Xuehong
The photocatalytic degradation of a cationic dye, rhodamine 6G (Rh-6G) under UV light irradiation was carried out. Rh-6G was completely decolorized in 180 min of photo-oxidative degradation period. The extent of degradation was confirmed performing total organic carbon (TOC) analysis, and up to 90.14%, TOC removal was achieved. Several critical analytical techniques including UV-Vis spectroscopy, high-performance liquid chromatography (HPLC), and ultra-performance liquid chromatography coupled with electrospray ionization mass spectrometry (UPLC/MS) were employed to scrutinize the mechanistic insights of the dye photodegradation. The degraded N-demethylation intermediates and several small molecular products were qualitatively identified, and a tentative photodegradation pathway was proposed. Toxicological evaluation of the degradation products was carried out three types of cell lines (MTT assay) and Triticum sativum seeds. In conclusion, enhanced biodegradability accompanied by toxicity reduction confirmed the promising efficiency of photocatalysis for Rh-6G degradation and therefore could be used for the remediation of textile effluents.
显示更多 [+] 显示较少 [-]Simultaneous Detection of 13 Endocrine Disrupting Chemicals in Water by a Combination of SPE-BSTFA Derivatization and GC-MS in Transboundary Rivers (France-Belgium)
2017
Sghaier, RafikaBen | Net, Sopheak | Ghorbel-Abid, Ibtissem | Bessadok, Salma | Le Coz, Maïwen | Hassan-Chehimi, DalilaBen | Trabelsi-Ayadi, Malika | Tackx, Michele | Ouddane, Baghdad
The occurrence of endocrine-disrupting chemicals (EDCs) in the aquatic environment has brought increasing concern due to their potential adverse impacts on ecosystems and humans. These compounds are generally present in complex water matrices, such as surface waters at trace levels (ng L⁻¹) making their analysis difficult. In this work, an analytical method for the simultaneous determination of 13 EDCs, including 5 steroid estrogens, 1 progestogen, 1 androgen, and 6 endocrine-disrupting phenols in water, was developed using solid phase extraction (SPE), derivatization, and gas chromatography-mass spectrometry (GC-MS). The method was validated by spiking the 13 EDCs to the interest matrix. The recovery was in the range of 52–71% with an average of 62%. The limits of quantification were 1 and 5–10 ng L⁻¹ for phenolic compounds and hormones, respectively. The validated method was applied to assess the contamination level of the targeted EDCs in 15 sites collected from six rivers located at the cross-border area of Northern France and Belgium. The majority of the considered compounds were detected in the sampling sites and among them, bisphenol A (BPA) was found at the highest level which can be up to 286 ng L⁻¹. However, NP was the most frequently detected, followed by BPA and PG.
显示更多 [+] 显示较少 [-]The Contribution of Pyrene Degrading Bacteria and Chemical Reagents to Scirpus triqueter Phytoremediation of Pyrene and Ni Co-contaminated Soil
2017
Hu, Xiaoxin | Zhang, Xinying | Liu, Xiaoyan | Cao, Liya | Chen, Jing | Huo, Zhuhao
Phytoremediation of organic pollutant and heavy metal (HM) co-contaminated soils shows many advantages and can be improved by adding chemical reagents or inoculating with degrading bacteria. In this study, pot culture experiments were performed to explore the effects of chemical reagents (nitrilotriacetic acid and alkyl polyglucoside), pyrene degrading bacteria HD-1, and their combination on phytoremediation efficiency for pyrene and nickel (Ni) co-contaminated soil by Scirpus triqueter. After a 60-day culture, plant biomass, pyrene dissipation from soil, Ni accumulation in plant, and Ni accessibility in co-contaminated soil were determined. Results showed that although the application of chemical reagents alone had no apparent effect on plant growth, their combination with the introduced HD-1 alleviated the inhibition effects on plant growth in co-contaminated soil. The dissipation of pyrene in the soil with plant (P), soil with bacteria (NPB), soil with chemical reagents (NPC) and soil with both of them (PBC) were 35.49, 51.36, 42.89, and 59.78%, respectively, and were higher than NP (19.52%) with neither of them. The Ni concentration in Scirpus triqueter of group with bacteria (PB), group with chemical reagents (PC) and group PBC increased to 100.40, 80.97 and 87.77 mg kg⁻¹ respectively when compared with that of group P (46.04 mg kg⁻¹) without bacteria or chemical reagents. Besides, inoculation with HD-1 or/and adding chemical reagents caused Ni to shift from less bioavailable forms to more bioavailable forms. This study suggested the contribution of pyrene degrading bacteria and chemical reagents to Scirpus triqueter phytoremediation of pyrene and Ni co-contaminated soil.
显示更多 [+] 显示较少 [-]Toxic Assessment of Cadmium Based on Online Swimming Behavior and the Continuous AChE Activity in the Gill of Zebrafish (Danio rerio)
2017
Pan, Hongwei | Zhang, Xu | Ren, Baixiang | Yang, Huanhuan | Ren, Zongming | Wang, Weiliang
The cadmium (Cd) contamination in the aquatic environment has attracted more and more attention due to its toxicity characteristics, e.g., accumulation in the environment, non-degradability, and the potential threat to the ecosystem. In this research, in order to illustrate the potential threat of heavy metal Cd to aquatic organisms, the online swimming behavior and the continuous acetylcholinesterase (AChE) activity in the gill of Zebrafish (Danio rerio) in 48 h exposure of cadmium chloride (CdCl₂) (4.26 mg/L (0.1 TU, toxic unit), 42.6 mg/L (1.0 TU), and 85.2 mg/L (2.0 TU)) are investigated. The behavior responses of D. rerio based on behavior strength (BS) have obvious dose-effect relationship, and lower BS values could be observed in the dark period at 13–21 h and 37–45 h in all treatments. The circadian rhythm could be observed even in all treatments (0.1, 1.0, and 2.0 TU), and the rhythm was disrupted with 1.0 TU at the end of the experiment whereas the lower (0.1 TU) and higher (2.0 TU) levels showed clear rhythms. These results suggested that the online BS values could illustrate the toxicity of CdCl₂ directly. The AChE activity in the gill is strongly inhibited by CdCl₂ based on the continuous sample results during 48 h exposure. The cross-correlation results using DCCA show a high correlation (r > 0.5) with extreme significance (p < 0.01), which suggest that the exposure in CdCl₂ can affect the AChE activity of D. rerio, and then damage the transduction signal due to neurotoxicity, which may induce decrease of swimming behavior, loss of coordination, and other kinds of behavior changes.
显示更多 [+] 显示较少 [-]Clay-to-Carbon Ratio Controls the Effect of Herbicide Application on Soil Bacterial Richness and Diversity in a Loamy Field
2017
Herath, H.M. L. I. | Moldrup, Per | de Jonge, LisW. | Nicolaisen, Mogens | Norgaard, Trine | Arthur, Emmanuel | Paradelo, Marcos
Soil texture and soil organic carbon (OC) influence the bacterial microenvironment and also control herbicide sorption. A field-scale exploratory study was conducted to investigate the potential interaction between soil texture parameters, herbicides, and soil bacterial richness and diversity. Glyphosate and bentazon were used to evaluate the herbicidal effect on bacterial community under different conditions created by clay and OC gradients in a loamy field. Metabarcoding by high-throughput sequencing of bacterial rDNA was used to estimate bacterial richness and diversity using OTUs, abundance-based coverage (ACE), Shannon diversity index, and phylogenetic diversity. In general, bacterial richness and diversity increased after bentazon application and decreased after glyphosate application. There was no significant effect for field locations with Dexter n (the ratio between clay and OC) values below 4.04 (the median of the values in the field study). The correlation coefficient (r) between bacterial richness and clay decreased after bentazon application, but increased after glyphosate application. Correlations between Dexter n and bacterial indices followed the same pattern, decreasing after bentazon application and increasing after glyphosate application. This indicated that the specific chemical nature of individual herbicides affected bacterial communities. This study reinforced the importance of including soil physical and chemical characteristics to explain the influence of pesticides on the variation in soil bacterial communities in agroecosystems.
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