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Does increased salinity influence the competitive outcome of two producer species? Полный текст
2017
Venâncio, C | Anselmo, E. | Soares, A. | Lopes, I.
Within the context of global climate changes, it is expected that low-lying coastal freshwater ecosystems will face seawater intrusion with concomitant increase in salinity levels. Increased salinity may provoke disruption of competitive relationships among freshwater species. However, species may be capable of acclimating to salinity, which, in turn, may influence the resilience of ecosystems. Accordingly, this work aimed at assessing the effects of multigenerational exposure to low levels of salinity in the competitive outcome of two species of green microalgae: Raphidocelis subcapitata and Chlorella vulgaris. To attain this, three specific objectives were delineated: (1) compare the toxicity of natural seawater (SW) and NaCl (as a surrogate of SW) to the two microalgae, (2) determine the capacity of the two microalgae species to acclimate to low salinity levels, and (3) assess the influence of exposure to low salinity levels in the competitive outcome of the two microalgae. Results revealed SW to be slightly less toxic than NaCl for the two microalgae. The EC₂₅,₇₂ ₕ for growth rate was 4.63 and 10.3 mS cm⁻¹ for R. subcapitata and 6.94 and 15.4 mS cm⁻¹ for C. vulgaris, respectively for NaCl and SW. Both algae were capable of acclimating to low levels of salinity, but C. vulgaris seemed to acclimate faster than R. subcapitata. When exposed in competition, under control conditions, the growth rates of C. vulgaris were lower than those of R. subcapitata. However, C. vulgaris was capable of acquiring competitive advantage equaling or surpassing the growth rate of R. subcapitata with the addition of NaCl or SW, respectively. The multigenerational exposure to low levels of salinity influenced the competitive outcome of the two algae both under control and salinity exposure. These results suggest that long-term exposure to low salinity stress can cause shifts in structure of algae communities and, therefore, should not be neglected since algae are at the basis of food web constituting important energetic resources to higher trophic levels.
Показать больше [+] Меньше [-]Pilot scale nanofiltration treatment of olive mill wastewater: a technical and economical evaluation Полный текст
2017
Sanches, S. | Fraga, M. C. | Silva, N. A. | Nunes, P. | Crespo, J. G. | Pereira, V. J.
The treatment of large volumes of olive mill wastewater is presently a challenge. This study reports the technical and economical feasibility of a sequential treatment of olive mill wastewater comprising a dissolved air flotation pre-treatment and nanofiltration. Different pilot nanofiltration assays were conducted in a concentration mode up to different volume reduction factors (29, 45, 58, and 81). Data attained demonstrated that nanofiltration can be operated at considerably high volume reduction factors and still be effective towards the removal of several components. A flux decline of approximately 50% was observed at the highest volume reduction factor, mainly due to increase of the osmotic pressure. Considerably high rejections were obtained across all experiments for total suspended solids (83 to >99%), total organic carbon (64 to 99%), chemical oxygen demand (53 to 77%), and oil and grease (67 to >82%). Treated water was in compliance with European legal limits for discharge regarding total suspended solids and oil and grease. The potential recovery of phenolic compounds was evaluated and found not relevant. It was demonstrated that nanofiltration is economically feasible, involving operation costs of approximately 2.56–3.08 €/m³, depending on the working plan schedule and volume reduction factor, and requiring a footprint of approximately 52 m² to treat 1000 m³ of olive mill wastewater.
Показать больше [+] Меньше [-]How and where to perform biomonitoring studies: different levels of toxic metal pollution are detected in the Alagados Reservoir in Southern Brazil Полный текст
2017
Doria, Halina Binde | Voigt, Carmen Lúcia | Sandrini-Neto, Leonardo | Campos, Sandro Xavier | de Oliveira-Ribeiro, Ciro Alberto | Randi, Marco Antonio Ferreira
The Alagados Reservoir located in the Brazilian city of Ponta Grossa is used to supply water for human consumption but is impacted by toxic metals. The current study combined chemical, biochemical, and multivariate analyses to determine the bioavailability of toxic metals at three sites (AL-A, AL-B, and AL-C) within the Alagados Reservoir. Metal bioaccumulation was analyzed in the liver, gills, and muscle tissue of a native fish species (Geophagus brasiliensis), and neurotoxicity, xenobiotic metabolism, and oxidative stress were evaluated using biochemical biomarkers. Additionally, histopathological studies were performed on the gills and the liver using scanning electron microscopy (SEM) and conventional light microscopy (LM), respectively. Overall, the bioaccumulation of metals, biomarkers of oxidative stress, and melanomacrophage counts indicate that the AL-C and the AL-A sites are the most and least affected by metals, respectively. The AL-B site presented the lowest acetylcholinesterase enzyme activity, a finding which was probably associated with the agricultural activities around this area of the reservoir. The biomarkers clearly revealed that toxic metals negatively affect all three sites studied herein and that human activity is the major source of pollutants. Despite the existence of different pollution levels within the Alagados Reservoir, it is still used as a human water supply.
Показать больше [+] Меньше [-]Simulating changes in cropping practices in conventional and glyphosate-resistant maize. II. Weed impacts on crop production and biodiversity Полный текст
2017
Colbach, Nathalie | Darmency, Henri | Fernier, Alice | Granger, Sylvie | Le Corre, Valérie | Messéan, Antoine
Simulating changes in cropping practices in conventional and glyphosate-resistant maize. II. Weed impacts on crop production and biodiversity Полный текст
2017
Colbach, Nathalie | Darmency, Henri | Fernier, Alice | Granger, Sylvie | Le Corre, Valérie | Messéan, Antoine
Overreliance on the same herbicide mode of action leads to the spread of resistant weeds, which cancels the advantages of herbicide-tolerant (HT) crops. Here, the objective was to quantify, with simulations, the impact of glyphosate-resistant (GR) weeds on crop production and weed-related wild biodiversity in HT maize-based cropping systems differing in terms of management practices. We (1) simulated current conventional and probable HT cropping systems in two European regions, Aquitaine and Catalonia, with the weed dynamics model FLORSYS; (2) quantified how much the presence of GR weeds contributed to weed impacts on crop production and biodiversity; (3) determined the effect of cultural practices on the impact of GR weeds and (4) identified which species traits most influence weed-impact indicators. The simulation study showed that during the analysed 28 years, the advent of glyphosate resistance had little effect on plant biodiversity. Glyphosate-susceptible populations and species were replaced by GR ones. Including GR weeds only affected functional biodiversity (food offer for birds, bees and carabids) and weed harmfulness when weed effect was initially low; when weed effect was initially high, including GR weeds had little effect. The GR effect also depended on cultural practices, e.g. GR weeds were most detrimental for species equitability when maize was sown late. Species traits most harmful for crop production and most beneficial for biodiversity were identified, using RLQ analyses. None of the species presenting these traits belonged to a family for which glyphosate resistance was reported. An advice table was built; the effects of cultural practices on crop production and biodiversity were synthesized, explained, quantified and ranked, and the optimal choices for each management technique were identified.
Показать больше [+] Меньше [-]Simulating changes in cropping practices in conventional and glyphosate-resistant maize. II. Weed impacts on crop production and biodiversity Полный текст
2017
Colbach, Nathalie | Darmency, Henri | Fernier, Alice | Granger, Sylvie | Le Corre, Valérie | Messean, Antoine | Agroécologie [Dijon] ; Institut National de la Recherche Agronomique (INRA)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université Bourgogne Franche-Comté [COMUE] (UBFC) | Unité Impacts Ecologiques des Innovations en Production Végétale (ECO-INNOV) ; Institut National de la Recherche Agronomique (INRA) | INRA, the European project AMIGA (Assessing and Monitoring Impacts of Genetically modified plants on Agro-ecosystems) [FP7-KBBE-2011-5-CP-CSA]; French project CoSAC [ANR-14-CE18-0007]; research programme "Assessing and reducing environmental risks from plant protection products" - French Ministry in charge of Ecology; research programme "Assessing and reducing environmental risks from plant protection products" - French Ministry in charge of Agriculture | ANR-14-CE18-0007,CoSAC,Conception de Stratégies durables de gestion des Adventices dans un contexte de Changement (climat, pratiques agricoles, biodiversité)(2014)
Overreliance on the same herbicide mode of action leads to the spread of resistant weeds, which cancels the advantages of herbicide-tolerant (HT) crops. Here, the objective was to quantify, with simulations, the impact of glyphosate-resistant (GR) weeds on crop production and weed-related wild biodiversity in HT maize-based cropping systems differing in terms of management practices. We (1) simulated current conventional and probable HT cropping systems in two European regions, Aquitaine and Catalonia, with the weed dynamics model FlorSys; (2) quantified how much the presence of GR weeds contributed to weed impacts on crop production and biodiversity; (3) determined the effect of cultural practices on the impact of GR weeds and (4) identified which species traits most influence weed-impact indicators. The simulation study showed that during the analysed 28 years, the advent of glyphosate resistance had little effect on plant biodiversity. Glyphosate-susceptible populations and species were replaced by GR ones. Including GR weeds only affected functional biodiversity (food offer for birds, bees and carabids) and weed harmfulness when weed effect was initially low; when weed effect was initially high, including GR weeds had little effect. The GR effect also depended on cultural practices, e.g. GR weeds were most detrimental for species equitability when maize was sown late. Species traits most harmful for crop production and most beneficial for biodiversity were identified, using RLQ analyses. None of the species presenting these traits belonged to a family for which glyphosate resistance was reported. An advice table was built; the effects of cultural practices on crop production and biodiversity were synthesized, explained, quantified and ranked, and the optimal choices for each management technique were identified.
Показать больше [+] Меньше [-]All-printed planar photoelectrochemical cells with digitated cathodes for the oxidation of diluted aqueous pollutants Полный текст
2017
Dzik, Petr | Veselý, Michal | Pachovská, Martina | Neumann-Spallart, Michael
A novel outline of a planar photoelectrochemical cell consisting of a semiconductor layer topped by subsequent layers of a digitated insulator and counter electrode is introduced. The use of vertically separated electrodes represents a major development in reducing the footprint (inactive areas) of planar electrochemical cells. The cells, consisting of a nanoparticular titania photoanode and a digitated, metallic cathode, were fabricated by a strictly additive process employing material printing as the exclusive deposition and patterning tool. Transparent conductive oxide-coated glass and polyethyleneterepthalate sheets were used as substrates; nanocrystalline titania dispersion bonded by a novel organosilica binder was used for the fabrication of the photoanode and gold or carbon inks for the fabrication of the digitated cathodes. Due to the digitated shaping of the cathode, photoelectrochemical response was not suffering from iR drop down to low electrolyte ionic strengths. The printed cells were used for electroassisted photocatalytic degradation experiments with aqueous solutions of coumarin. Considerable acceleration of the coumarin degradation rate compared to the plain photocatalytic mode was observed.
Показать больше [+] Меньше [-]Globalisation and its effect on pollution in Malaysia: the role of Trans-Pacific Partnership (TPP) agreement Полный текст
2017
Solarin, Sakiru Adebola | Al-mulali, Usama | Sahu, Pritish Kumar
The main objective of this study is to investigate the influence of the globalisation (Trans-Pacific Partnership (TPP) agreement in particular) on air pollution in Malaysia. To achieve this goal, the Autoregressive Distributed Lag (ARDL) model, Johansen cointegration test and fully modified ordinary least square (FMOLS) methods are utilised. CO₂ emission is used as an indicator of pollution while GDP per capita and urbanisation serve as its other determinants. In addition, this study uses Malaysia’s total trade with 10 TPP members as an indicator of globalisation and analyse its effect on CO₂ emission in Malaysia. The outcome of this research shows that the variables are cointegrated. Additionally, GDP per capita, urbanisation and trade between Malaysia and its 10 TPP partners have a positive impact on CO₂ emissions in general. Based on the outcome of this research, important policy implications are provided for the investigated country.
Показать больше [+] Меньше [-]Discarded seeds from red pepper (Capsicum annum) processing industry as a sustainable source of high added-value compounds and edible oil Полный текст
2017
Azabou, Samia | Taheur, FadiaBen | Jridi, Mourad | Bouaziz, Mohamed | Nasri, Moncef
The chemical composition and the antioxidant properties of Capsicum annum discarded seeds from processing industry with their corresponding extracted oil were investigated. C. annum seeds had high levels of crude proteins (18.30%), crude oil (11.04%), and dietary fibers (60.96%). The lipophilic fraction of C. annum seeds showed higher radical scavenging activity compared to their hydrophilic fraction, while this latter exhibited the highest reducing power. The results of fatty acid composition showed that fatty acids present in C. annum seed oil were mainly polyunsaturated (84.23%), with linoleic acid being the major polyunsaturated fatty acid (70.93%). The major monounsaturated fatty acid was oleic acid (12.18%), while the main saturated fatty acid was palmitic acid (11.90%). C. annum seed oil showed high absorbance in the UV-B, UV-A, and visible ranges. Owing to their composition, C. annum seeds discarded from pepper processing industry as by-product could be potentially used as high added-value ingredients in some food or nutraceutical formulations because they are well endowed with essential nutriments required for human health.
Показать больше [+] Меньше [-]Emission characteristics of PBDEs during flame-retardant plastics extruding process: field investigation and laboratorial simulation Полный текст
2017
Deng, Chao | Li, Ying | Li, Jinhui | Chen, Yuan | Li, Huafen
Though mechanical recycling of WEEE plastics is supposed to be a promising method, PBDEs release and the resulting contamination during its processing remain unclear yet. The distribution of PBDEs pollution in production lines was investigated from two flame-retardant plastic modification plants in Southern China. This was followed by laboratory simulation experiments to characterize the emission processes. PBDEs concentrations ranged from 37 to 31,305 ng/L in cooling water and from 40,043 to 216,653 ng/g dry wt in solid samples taken during the field investigation. In the laboratory simulation, concentrations ranged from 146 to 433 ng/L in cooling water and from 411,436 to 747,516 ng/Nm³ in flue gas. All samples were dominated by BDE-209 among the congeners. Temperatures and impurities in plastic substrate can significantly affect PBDEs release. Special attention should be paid to the risks of water directly discharge from the cooling system, especially for the biological sludge and sediments, as well as flue gas emissions to the environment.
Показать больше [+] Меньше [-]Genotoxic risk assessment in professionals working hairdressers area using buccal micronucleus assay, in Aydın City, Turkey Полный текст
2017
Aslantürk, Özlem Sultan | Aşkin Çelik, Tülay
The aim of this study was to determine the genotoxic risk of professional hairdressers in Aydın City, Turkey, through investigating the micronucleus frequencies in buccal mucosa epithelial cells. All the hairdresser working hairdresser area were included in the genotoxic risk group (GRG = 20) in Aydın City, Turkey. The control group (CG = 20) comprised healthy individuals matching the gender and age of the GRG. Buccal mucosal scraping from all the 40 subjects of GRG (10 women and 10 men) and CG (10 women and 10 men) was stained with Giemsa stain and observed under light microscope (×40) for the presence of micronuclei (M 10 N) and karyolysis, pyknosis, condensed chromatin, karyorrhexis, nuclear bud, and binucleates in the exfoliated epithelial cells. There are significance between the incidence of MN in GRG and CG (P = <0.005) using one-way ANOVA, Kolmogorov-Smirnov Z test, and Spearman Rank Correlation Tests.
Показать больше [+] Меньше [-]Evaluation of zeolite-supported microscale zero-valent iron as a potential adsorbent for Cd2+ and Pb2+ removal in permeable reactive barriers Полный текст
2017
Kong, Xiangke | Huang, Guoxin | Han, Zhantao | Xu, Youming | Zhu, Ming | Zhang, Zhaoji
A new composite adsorbent, zeolite-supported microscale zero-valent iron (Z-mZVI) was evaluated as a potential adsorbent for the removal of Cd²⁺ and Pb²⁺ from aqueous solution using batch and column experiments. Adsorption isotherms were well fitted by Langmuir model, and the maximum adsorption capacity was 63.14 mg/g for Cd²⁺ and 154.61 mg/g for Pb²⁺, respectively. Both adsorption processes followed the pseudo-second-order model which indicated that the rate-limiting step for different initial concentration was dominated by chemical adsorption process. The coexistence of Cd²⁺ and Pb²⁺ caused the reduction of Cd²⁺ removal efficiency, but not for Pb²⁺. Z-mZVI has a high removal capacity for Cd²⁺ and Pb²⁺ over a wide pH range (3.0–6.8) as well as in the presence of competitive Ca²⁺ or Mg²⁺ ions (<2 mmol/L). Moreover, Z-mZVI shows a high immobilization capacity for the adsorbed Cd²⁺ and Pb²⁺ products, even at the acid solution (pH = 3.95). Column experiment confirmed that Z-mZVI could simultaneously remove Cd²⁺ and Pb²⁺ from solution efficiently. Thomas model can simulate the equilibrium adsorption capacity of Cd²⁺ and Pb²⁺ of the Z-mZVI column well. This study demonstrates that Z-mZVI is an efficient and promising reactive material in permeable reactive barriers for Cd²⁺ and Pb²⁺ removal from aqueous solution.
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