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Résultats 3531-3540 de 4,308
Nutrient leaching, soil pH and changes in microbial community increase with time in lead-contaminated boreal forest soil at a shooting range area Texte intégral
2017
Selonen, Salla | Setälä, Heikki
Despite the known toxicity of lead (Pb), Pb pellets are widely used at shotgun shooting ranges over the world. However, the impacts of Pb on soil nutrients and soil microbes, playing a crucial role in nutrient cycling, are poorly understood. Furthermore, it is unknown whether these impacts change with time after the cessation of shooting. To shed light on these issues, three study sites in the same coniferous forest in a shooting range area were studied: an uncontaminated control site and an active and an abandoned shooting range, both sharing a similar Pb pellet load in the soil, but the latter with a 20-year longer contamination history. Soil pH and nitrate concentration increased, whilst soil phosphate concentration and fungal phospholipid fatty acid (PLFA) decreased due to Pb contamination. Our results imply that shooting-derived Pb can influence soil nutrients and microbes not only directly but also indirectly by increasing soil pH. However, these mechanisms cannot be differentiated here. Many of the Pb-induced changes were most pronounced at the abandoned range, and nutrient leaching was increased only at that site. These results suggest that Pb disturbs the structure and functions of the soil system and impairs a crucial ecosystem service, the ability to retain nutrients. Furthermore, the risks of shooting-derived Pb to the environment increase with time.
Afficher plus [+] Moins [-]Preparation, characterization and environmental applications of Sr1 − x (La,Bi) x TiO3 perovskites immobilized on Ni-foam: photodegradation of the Acid Orange 7 Texte intégral
2017
Nunes, M. J. | Lopes, A. | Pacheco, M. J. | Ciríaco, L.
The Sr₁ ₋ ₓ La ₓ TiO₃ (0 ≤ x ≤ 0.4) and Sr₁ ₋ ₓ Bi ₓ TiO₃ (0 ≤ x ≤ 0.3) perovskites were prepared via solid state reaction by partially replacing the Sr²⁺ ions in the SrTiO₃ structure by La³⁺ or Bi³⁺ ions, characterized and utilized as photocatalysts immobilized in Ni-foam substrate in the degradation of the azo dye Acid Orange 7 (AO7). For both perovskite families, the XRD data reveal the existence of a predominant well-crystallized phase, belonging to a cubic perovskite in a Pm3m space group, with the presence of other minority phases. The characteristic dimension and the volume of the cell decrease with the introduction in the SrTiO₃ lattice of the La³⁺ or Bi³⁺ ions. The grain size of the Sr₁ ₋ ₓ La ₓ TiO₃ samples is around 100 nm and slightly lower for the Sr₁ ₋ ₓ Bi ₓ TiO₃ samples. Regarding the utilization of the prepared perovskite powders deposited over the Ni-foam substrates as catalysts in the photodegradation of AO7 solutions, the results show an improvement in the performance of the films of the substituted perovskite when compared to the SrTiO₃ perovskite, being the best results obtained with Sr₀.₉Bi₀.₁TiO₃.
Afficher plus [+] Moins [-]Effect of operational factors on bioregeneration of binary phenol and 4-chlorophenol-loaded granular activated carbon using PVA-immobilized biomass cryogels Texte intégral
2017
Leong, Kwok-Yii | Adnan, Rohana | Lim, Poh-Eng | Ng, Si-Ling | Seng, Chye-Eng
The effects of dry biomass density in cryogel beads, shaking speed and initial concentration ratio of phenol to 4-chlorophenol (4-CP) on the bioregeneration efficiencies of binary phenol and 4-CP-loaded granular activated carbon (GAC) for phenol and 4-CP, respectively, were investigated under the simultaneous adsorption and biodegradation approach. The results revealed higher bioregeneration efficiencies of binary-loaded GAC for phenol and 4-CP at higher dry biomass density but moderate shaking speed. The optimum dry biomass density in cryogel beads and shaking speed for use in bioregeneration were found to be 0.01 g/mL and 250 rpm, respectively. With respect to the initial phenol to 4-CP concentration ratio, the bioregeneration efficiencies were lower under increasing phenol and 4-CP initial concentrations, respectively, with the effect being more conspicuous under increasing 4-CP concentration. Higher bioregeneration efficiencies were achieved with the use of immobilized rather than suspended biomasses.
Afficher plus [+] Moins [-]Leaching of Cu, Cd, Pb, and phosphorus and their availability in the phosphate-amended contaminated soils under simulated acid rain Texte intégral
2017
Cui, Hongbiao | Zhang, Shiwen | Li, Ruyan | Yi, Qitao | Zheng, Xuebo | Hu, Youbiao | Zhou, Jing
Phosphate amendments have been used to immobilize heavy metal-contaminated soils. However, phosphate amendments contain large amounts of phosphorus, which could leach out to potentially contaminate groundwater and surface water. A laboratory column leaching experiment was designed to study the effects of simulated acid rain (SAR) on the potential release of copper (Cu), lead (Pb), cadmium (Cd), and phosphorus (P), and their availability after immobilizing with hydroxyapatite (HAP) and potassium dihydrogen phosphate (PDP). The application of HAP and PDP enhanced the leachate electrical conductivity, total organic carbon, and pH. Higher P was found in the PDP- (>4.29 mg L⁻¹) and HAP-treated (>1.69 mg L⁻¹) columns than that in untreated (<0.2 mg L⁻¹) columns, and they were both over the class V limit (0.4 mg L⁻¹) mandated by the Chinese National Quality Standards for Surface Waters (GB 3838-2002). PDP application decreased the leachate Cu, Pb, and Cd effectively; however, HAP addition increased leachate Cu and Pb. HAP and PDP applications decreased the soil CaCl₂-extractable and exchangeable fraction of Cu, Pb, and Cd, and increased resin P. However, eluviations transformed the heavy metals from inactive to active fractions and reduced soil labile P. These findings showed that HAP and PDP had a potential risk of excessive P-induced eutrophication. Meanwhile, more attention should be paid to the leaching loss of multiple metals because phosphate amendments might promote the leaching of some metals while immobilizing others.
Afficher plus [+] Moins [-]Photolysis of pharmaceuticals and personal care products in the marine environment under simulated sunlight conditions: irradiation and identification Texte intégral
2017
Ali, Aasim Musa Mohamed | Kallenborn, Roland | Sydnes, Leiv Kristen | Rønning, Helene Thorsen | Alarif, Walied Mohamed | Al-Lihaibi, Sultan
The photochemical fate of 16 pharmaceuticals and personal care products (PPCPs) found in the environment has been studied under controlled laboratory conditions applying a sunlight simulator. Aqueous samples containing PPCPs at environmentally relevant concentrations were extracted by solid-phase extraction (SPE) after irradiation. The exposed extracts were subsequently analysed by liquid chromatography combined with triple quadrupole mass spectrometry (HPLC-MS/MS) for studying the kinetics of photolytic transformations. Almost all exposed PPCPs appeared to react with a half-life time (τ ₁/₂) of less than 30 min. For ranitidine, sulfamethoxazole, diclofenac, warfarin, sulfamethoxazole and ciprofloxacin, τ₁/₂ was found to be even less than 5 min. The structures of major photolysis products were determined using quadrupole-time-of-flight mass spectrometry (QToF) and spectroscopic data reported in the literature. For diclofenac, the transformation products carbazol-1-yl-acidic acid and 8-chloro-9H-carbazol-1-yl-acetic acid were identified based on the mass/charge ratio of protonated ions and their fragmentation pattern in negative electrospray ionization (ESI⁻-QTOF). Irradiation of carbamazepine resulted in three known products: acridine, carbamazepine-10,11-epoxide, and 10,11-dihydro-10,11-dihydroxy-carbamazepine, whereas acetaminophen was photolytically transformed to 1-(2-amino-5 hydroxyphenyl) ethenone. These photochemical products were subsequently identified in seawater or fish samples collected at sites exposed to wastewater effluents on the Saudi Arabian coast of the Red Sea.
Afficher plus [+] Moins [-]Environment polluting conventional chemical control compared to an environmentally friendly IPM approach for control of diamondback moth, Plutella xylostella (L.), in China: a review Texte intégral
2017
Shakeel, Muhammad | Fārūq, Muḥammad | Nasim, Wajid | Akram, Waseem | Khan, Fawad Zafar Ahmad | Jaleel, Waqar | Zhu, Xun | Yin, Haichen | Li, Shuzhong | Shah, Fahad | Hussain, Saddam | Chauhan, Bhagirath Singh | Jin, Fengliang
The diamondback moth, Plutella xylostella, is recognized as a widely distributed destructive insect pest of Brassica worldwide. The management of this pest is a serious issue, and an estimated annual cost of its management has reached approximately US$4 billion. Despite the fact that chemicals are a serious threat to the environment, lots of chemicals are applied for controlling various insect pests especially P. xylostella. An overreliance on chemical control has not only led to the evolution of resistance to insecticides and to a reduction of natural enemies but also has polluted various components of water, air, and soil ecosystem. In the present scenario, there is a need to implement an environmentally friendly integrated pest management (IPM) approach with new management tactics (microbial control, biological control, cultural control, mating disruption, insecticide rotation strategies, and plant resistance) for an alternative to chemical control. The IPM approach is not only economically beneficial but also reduces the environmental and health risks. The present review synthesizes published information on the insecticide resistance against P. xylostella and emphasizes on adopting an alternative environmentally friendly IPM approach for controlling P. xylostella in China.
Afficher plus [+] Moins [-]Sequential use of the STICS crop model and of the MACRO pesticide fate model to simulate pesticides leaching in cropping systems Texte intégral
2017
Lammoglia, Sabine-Karen | Moeys, Julien | Barriuso, Enrique | Larsbo, Mats | Marín-Benito, Jesús-María | Justes, Eric | Alletto, Lionel | Ubertosi, Marjorie | Nicolardot, Bernard | Munier-Jolain, Nicolas | Mamy, Laure
Sequential use of the STICS crop model and of the MACRO pesticide fate model to simulate pesticides leaching in cropping systems Texte intégral
2017
Lammoglia, Sabine-Karen | Moeys, Julien | Barriuso, Enrique | Larsbo, Mats | Marín-Benito, Jesús-María | Justes, Eric | Alletto, Lionel | Ubertosi, Marjorie | Nicolardot, Bernard | Munier-Jolain, Nicolas | Mamy, Laure
The current challenge in sustainable agriculture is to introduce new cropping systems to reduce pesticides use in order to reduce ground and surface water contamination. However, it is difficult to carry out in situ experiments to assess the environmental impacts of pesticide use for all possible combinations of climate, crop, and soils; therefore, in silico tools are necessary. The objective of this work was to assess pesticides leaching in cropping systems coupling the performances of a crop model (STICS) and of a pesticide fate model (MACRO). STICS-MACRO has the advantage of being able to simulate pesticides fate in complex cropping systems and to consider some agricultural practices such as fertilization, mulch, or crop residues management, which cannot be accounted for with MACRO. The performance of STICS-MACRO was tested, without calibration, from measurements done in two French experimental sites with contrasted soil and climate properties. The prediction of water percolation and pesticides concentrations with STICS-MACRO was satisfactory, but it varied with the pedoclimatic context. The performance of STICS-MACRO was shown to be similar or better than that of MACRO. The improvement of the simulation of crop growth allowed better estimate of crop transpiration therefore of water balance. It also allowed better estimate of pesticide interception by the crop which was found to be crucial for the prediction of pesticides concentrations in water. STICS-MACRO is a new promising tool to improve the assessment of the environmental risks of pesticides used in cropping systems.
Afficher plus [+] Moins [-]Sequential use of the STICS crop model and of the MACRO pesticide fate model to simulate pesticides leaching in cropping systems Texte intégral
2017
Lammoglia, Sabine-Karen | Moeys, Julien | Barriuso, Enrique | Larsbo, Mats | Marín-Benito, Jesús-María | Justes, Eric | Alletto, Lionel | Ubertosi, Marjorie | Nicolardot, Bernard | Munier-Jolain, Nicolas | Mamy, Laure | Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS) ; Institut National de la Recherche Agronomique (INRA)-AgroParisTech | Departement of Soil and Environment ; Swedish University of Agricultural Sciences = Sveriges lantbruksuniversitet (SLU) | CSIC40-52 Cordel de Merinas ; Institute of Natural Resources and Agrobiology of Salamanca (IRNASA) | AGroécologie, Innovations, teRritoires (AGIR) ; Institut National de la Recherche Agronomique (INRA)-Institut National Polytechnique (Toulouse) (Toulouse INP) ; Université de Toulouse (UT)-Université de Toulouse (UT) | 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)
International audience | The current challenge in sustainable agriculture is to introduce new cropping systems to reduce pesticides use in order to reduce ground and surface water contamination. However, it is difficult to carry out in situ experiments to assess the environmental impacts of pesticide use for all possible combinations of climate, crop, and soils; therefore, in silico tools are necessary. The objective of this work was to assess pesticides leaching in cropping systems coupling the performances of a crop model (STICS) and of a pesticide fate model (MACRO). STICS-MACRO has the advantage of being able to simulate pesticides fate in complex cropping systems and to consider some agricultural practices such as fertilization, mulch, or crop residues management, which cannot be accounted for with MACRO. The performance of STICS-MACRO was tested, without calibration, from measurements done in two French experimental sites with contrasted soil and climate properties. The prediction of water percolation and pesticides concentrations with STICS-MACRO was satisfactory, but it varied with the pedoclimatic context. The performance of STICS-MACRO was shown to be similar or better than that of MACRO. The improvement of the simulation of crop growth allowed better estimate of crop transpiration therefore of water balance. It also allowed better estimate of pesticide interception by the crop which was found to be crucial for the prediction of pesticides concentrations in water. STICS-MACRO is a new promising tool to improve the assessment of the environmental risks of pesticides used in cropping systems.
Afficher plus [+] Moins [-]Toxicity evaluation of vinasse and biosolid samples in diplopod midgut: heat shock protein in situ localization Texte intégral
2017
Coelho, Maria Paula Mancini | Moreira-de-Sousa, Cristina | de Souza, Raphael Bastão | Ansoar-Rodríguez, Yadira | Silva-Zacarin, Elaine Cristina Mathias | Fontanetti, Carmem Silvia
Large amounts of residues generated by agricultural, urban and industrial activities are dumped daily on the soil. This practice deserves special attention because it causes serious environmental problems. This study evaluated the toxic potential of the sugarcane vinasse, a by-product of the sugar-alcohol industry, and the biosolid, a residue produced by wastewater treatment plants, both widely used as fertilizers. The evaluation was performed through bioassays using a typical soil bioindicator, the diplopod Rhinocricus padbergi. The specimens were exposed to soils containing these residues in concentrations that are compatible with the Brazilian regulation for agricultural use. Semi-quantitative immunolabelling analyses of the stress protein HSP70 were performed on the midgut of the studied diplopods. There was a significant increase in the immunolabelling of HSP70 proteins as a response to xenobiotics from both residues, particularly in regions where the function of the cells is the detoxification of the organ (e.g. the hepatic cell layer and specific regions of the epithelium). Higher immunolabelling was observed in the specimens exposed to vinasse in comparison with the biosolid exposure. This demonstrates that the substances in the tested residues had proteotoxic action in the exposed animals and induced a cytoprotective response, which led to higher stress protein immunolabelling. Therefore, caution is needed for the use of such residues in agriculture.
Afficher plus [+] Moins [-]Upgrading the hydrolytic potential of immobilized bacterial pretreatment to boost biogas production Texte intégral
2017
Ushani, U. | Kavitha, S. | Johnson, M. | Yeom, Ick Tae | Banu, J Rajesh
In this study, surfactant dioctyl sodium sulphosuccinate (DOSS)-mediated immobilized bacterial pretreatment of waste activated sludge (WAS) was experimentally proved to be an efficient and economically feasible process for enhancing the biodegradability of WAS. The maximal floc disruption with negligible cell cleavage was achieved at surfactant dosage of 0.009 g/g SS. Results of the outcome of bacterial pretreatment of sludge biomass revealed that chemical oxygen demand (COD) solubilization for deflocculated (EPS removed—bacterially pretreated) sludge was 20 %, which was higher than that of flocculated (14 %) or control (5 %). The pretreatment was swift in deflocculated sludge with a rate constant of about 0.064 h⁻¹. Biochemical methane potential (BMP) assay resulted in significant methane yield at 0.24 gCOD/gCOD for deflocculated sludge. Economic assessment of the proposed method showed a net profit of about 57.39 USD/ton of sludge.
Afficher plus [+] Moins [-]miR-21 is involved in skeletal deficiencies of zebrafish embryos exposed to polychlorinated biphenyls Texte intégral
2017
Ju, Li | Zhou, Zhiwen | Jiang, Bo | Lou, Yue | Zhang, Zhiqun
Polychlorinated biphenyl (PCB) exposure increases the incidence and severity of skeletal diseases, but little is known about the mechanisms that mediate this relationship. We exposed zebrafish embryos to PCB₁₂₅₄ and assessed the changes in bone morphology protein receptor II (BMPRII), which is involved in bone formation and embryonic development, miRNA-21, for which BMPRII is a known target, and calcium metabolism. PCB₁₂₅₄ upregulated the expression of miR-21 and suppressed BMPRII expression. The inhibition of miR-21 reversed the downregulation of BMPRII and alleviated the PCB₁₂₅₄-induced loss of calcium. These findings suggest new biomarkers of developmental defects of the skeleton caused by PCBs.
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