خيارات البحث
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Environmental concentration of fluoxetine disturbs larvae behavior and increases the defense response at molecular level in zebrafish (Danio rerio)
2019
Parolini, Marco | Ghilardi, Anna | De Felice, Beatrice | Del Giacco, Luca
Fluoxetine (FLX) is one of the main antidepressants used worldwide. After human use, FLX enters the aquatic ecosystems, where it has commonly detected in the high ng/L concentration range. Several investigations have shown that exposure to different concentrations of FLX caused different adverse effects towards a number of aquatic species. However, the information on the onset and the relationship between molecular and behavioral FLX-induced effects remains scant. The aim of this study was to assess the effects induced by two FLX concentrations, namely 50 ng/L and 500 ng/L, on swimming activity of zebrafish (Danio rerio) larvae at 96-h post-fertilization (hpf) and to investigate if such behavioral effects were related to modulation of the expression of oxidative stress-related (sod1, sod2, cat, gpxa, and gst), stress- and anxiety-related (oxtl, prl2, npy, and ucn3l) genes, and genes encoding for the transporters of the main neurotransmitters (slc6a3, slc6a4a, slc6a4b, slc6a11). Fluoxetine exposure altered the swimming behavior of larvae, as shown by the reduction of the distance traveled by treated larvae in response to an external stimulus. Such behavioral change was related, at molecular level, to an enhanced expression of sod1, cat, and gpxa, suggesting an overproduction of pro-oxidant molecules. In addition, FLX modulated the expression of oxtl, slc6a4a, slc6a4b, and slc6a11, suggesting its capability to affect anxiety- and neurotransmitter-related genes.
اظهر المزيد [+] اقل [-]Impacts of different aged landfill leachate on PVC corrosion
2019
Zhao, Rui | Wang, Xiaoqian | Chen, Xiaolang | Liu, Yiyun
Landfill leachate is generally transferred to in situ facilities for advanced treatment by using a pipe system. Because of its harmful and complex compounds, leachate may react with pipe materials, leading to corrosion and scaling. This experimental study uses typical PVC pipe material and investigates its anti-corrosion performance by placing the material samples into different aged leachates. By evaluating the changes in different experimental parameters, including calcium, magnesium, and chloride ion concentration, oxidation-reduction potential, dissolved oxygen, and pH, combined with a characterization of the material properties, we infer the main causes of pipe scaling-corrosion. Results show that the scaling is more intense in the younger leachate, and the concentration of calcium ions is the dominant influencing factor. The scaling might be resulted from joint actions of chemical precipitation and microbial metabolic activities. It is expected the study to provide useful insights into taking effective actions on anti-clogging, and enhance pipes design by selection of appropriate materials for future modification.
اظهر المزيد [+] اقل [-]Differentiation between physical and chemical effects of oil presence in freshly spiked soil during rhizoremediation trial
2019
Hucheina, Imarāna | Puschenreiter, Markus | Gerhard, Soja | Sani, Syed Gul Abbas Shah | Khan, Waqas-us-din | Reichenauer, Thomas G.
Petroleum contamination and its remediation via plant-based solutions have got increasing attention by environmental scientists and engineers. In the current study, the physiological and growth responses of two diesel-tolerant plant species (tolerance limit: 1500–2000 mg/kg), Italian ryegrass (Lolium multiflorum) and Birdsfoot trefoil (Lotus corniculatus), have been investigated in vegetable oil– and diesel oil–amended soils. A long-term (147-day) greenhouse pot experiment was conducted to differentiate the main focus of the study: physical and chemical effects of oil (vegetable and diesel) in freshly spiked soils via evaluating the plant performance and hydrocarbon degradation. Moreover, plant performance was evaluated in terms of seed germination, plant shoot biomass, physiological parameters, and root biomass. Addition of both diesel oil and vegetable oil in freshly spiked soils showed deleterious effects on seedling emergence, root/shoot biomass, and chlorophyll content of grass and legume plants. Italian ryegrass showed more sensitivity in terms of germination rate to both vegetable and diesel oil as compared to non-contaminated soils while Birdsfoot trefoil reduced the germination rate only in diesel oil–impacted soils. The results of the current study suggest that both physical and chemical effects of oil pose negative effects of plant growth and root development. This observation may explain the phenomenon of reduced plant growth in aged/weathered contaminated soils during rhizoremediation experiments.
اظهر المزيد [+] اقل [-]Developmental toxicity and apoptosis in zebrafish embryos induced by low-dose γ-ray irradiation
2019
Zhao, Weichao | Hu, Nan | Ding, Dexin | Long, Dingxin | Li, Sheng | Li, Guangyue | Zhang, Hui
In this paper, the developmental toxicity and apoptosis in zebrafish (Danio rerio) embryos induced by 0.01, 0.05, and 0.10-Gy γ-ray irradiation were investigated and verified by single cell gel electrophoresis, acridine orange staining, flow cytometry, transmission electron microscopy, digital gene expression sequencing, and Western blot analysis. DNA damage, deformity rates, and apoptosis of zebrafish embryos were found to increase significantly with the increase of irradiation dose, and survival and hatching rates significantly decreased when the irradiation dose exceeds 0.10 and 0.05 Gy, respectively. Exposure to 0.10-Gy γ-ray irradiation resulted in the swelling of cell mitochondria of zebrafish embryos and changes in their intracellular vacuoles. mRNA and protein expression levels of Shh (sonic hedgehog 19 KDa) and Smo (smoothened 86 KDa) of Hh signaling pathway associated with the development of early embryos significantly increased with the increase of irradiation dose. Expression of the AKT (56 KDa) and PiK3r3 (55 KDa) genes, which are anti-apoptotic and involved with the PI3K/Akt signaling pathway, significantly decreased, while expression of the bada gene, which is pro-apoptotic, significantly increased. The results show that γ-ray irradiations of 0.01 and 0.05 Gy can induce developmental toxicity and apoptosis in zebrafish embryos via Hh and PI3K/Akt signaling pathways, respectively.
اظهر المزيد [+] اقل [-]Environmental assessment in health care organizations
2019
Romero, Isabel | Carnero, María Carmen
The aim of this research is to design a multi-criteria model for environmental assessment of health care organizations. This is a model which guarantees the objectivity of the results obtained, is easy to apply, and incorporates a series of criteria, and their corresponding descriptors, relevant to the internal environmental auditing processes of the hospital. Furthermore, judgments were given by three experts from the areas of health, the environment, and multi-criteria decision techniques. From the values assigned, geometric means were calculated, giving weightings for the criteria of the model. This innovative model is intended for application within a continuous improvement process. A practical case from a Spanish hospital is included at the end. Information contained in the sustainability report provided the data needed to apply the model. The example contains all the criteria previously defined in the model. The results obtained show that the best-satisfied criteria are those related to energy consumption, generation of hazardous waste, legal matters, environmental sensitivity of staff, patients and others, and the environmental management of suppliers. On the other hand, those areas returning poor results are control of atmospheric emissions, increase in consumption of renewable energies, and the logistics of waste produced. It is recommended that steps be taken to correct these deficiencies, thus leading to an acceptable increase in the sustainability of the hospital.
اظهر المزيد [+] اقل [-]Enhanced nitrogen removal in biochar-added surface flow constructed wetlands: dealing with seasonal variation in the north China
2019
Li, Jing | Fan, Jinlin | Liu, Daoxing | Hu, Zhen | Zhang, Jian
In the present study, the performance of surface flow constructed wetlands (SFCWs) added with different dosage of biochar (group A 0%, group B 10%, group C 20%; v/v) was investigated, to evaluate the effect of biochar on nitrogen removal of a constructed wetland. No significant difference was observed in NH₄⁺-N removal among three groups even during different seasons. Labile organic carbon released from biochar distinctly enhanced denitrification process, which improved NO₃⁻-N removal efficiency by 4.58% in group B and 10.33% in group C. More importantly, compared with group A, biochar addition increased plant N removal by 82.24% and 192.11% in groups B and C, respectively. This result indicated that biochar could increase the accumulation of plant net biomass. In addition, TN removal of group A was much lower at low temperature (4.9 °C). However, no obvious influence of temperature on TN removal was observed in groups B and C with biochar addition. Microbial community analysis showed that, compared with that in group A, the total relative abundance of the main denitrification bacteria (Proteobacteria, Firmicutes, and Bacteroidetes) increased by 0.81% in group B and 13.63% in group C. These results provide a reasonable strategy for improving the performance of SFCWs under cold climate.
اظهر المزيد [+] اقل [-]Effect of cation type in mixed Ca-Na systems on transport of sulfonamide antibiotics in saturated limestone porous media
2019
Sun, Kaixuan | Sun, Yuanyuan | Gao, Bin | Xu, Hongxia | Wu, Jichun
Retention and transport of sulfonamides (SAs) in subsurface can strongly affect groundwater quality. In this work, a range of laboratory batch sorption and column transport experiments were conducted to determine the effect of cation type in mixed Ca-Na systems on the retention and transport of two typical SAs, sulfadimethoxine (SDM) and sulfacetamide (SCA), in saturated limestone porous media. Column experimental data showed divalent cation Ca²⁺ played a more important role than monovalent cation Na⁺ in decreasing the transport of only SDM in co-cation systems in the saturated limestone media. Further, in the single-cation (i.e., including either Ca²⁺ or Na⁺) system, increasing ionic strength (IS) of either NaCl or CaCl₂ had little effect on SCA transport; however, increasing of IS of CaCl₂ promoted the retention of SDM in the saturated limestone porous media. This is mainly due to the cation bridging effect of Ca²⁺ on SDM and limestone. Overall, SDM showed much higher retention in the limestone columns than SCA, which can be attributed to the two SAs’ different physicochemical properties. Moreover, limestone showed stronger ability to retain the two SAs than quartz sand. Findings in this study suggest that cation type and the concentration of certain electrolyte (e.g., CaCl₂) as well as medium type play an important role in controlling the environmental fate and transport of antibiotics.
اظهر المزيد [+] اقل [-]Nitrogen and phosphorus removal from wastewater by sand with wheat straw
2019
Le, Thi Huong Xuan | Mosley, Luke | Marschner, Petra
Wheat straw amendment to sandy soil has the potential to remove nutrients from wastewater. This study investigated the ability of wheat straw to remove inorganic nitrogen (N) and phosphorus (P) from wastewater when mixed into sand at different rates. Wastewater from a sewage treatment plant was added to sand alone and amended with different wheat straw rates 2.5, 5, 7.5, 10, and 12.5 g wheat straw kg⁻¹ so that the sand was covered with about 15 cm of wastewater. Leaching was carried out after 4, 8, and 16 days and inorganic N and P were analysed after leaching in both the leachate and sand, as well as N₂O and CO₂ release. In the amended sand, nitrate was about fourfold lower throughout the experiment compared to sand alone. Ammonium was twofold higher than sand alone at 12.5 g straw kg⁻¹ throughout the experiment and on day 16 also at ≥ 5 g straw kg⁻¹. Leachate inorganic N concentration was up to 70-fold higher in sand alone than in amended soils irrespective of straw rate. On day 16, P leaching was about threefold lower and P retention was 40% higher in all amended treatments than sand alone. The redox potential in sand alone was higher than with straw amendments. With straw amendment, the release of CO₂ per day was six times higher than with sand alone and increased with straw rates, but very little N₂O and CH₄ was released throughout the experiment. It can be concluded that amendment of sand with wheat straw can remove large proportions of inorganic N and P from wastewater, even at low straw rates. Likely mechanisms for retention are dissimilatory nitrate reduction and subsequent binding of ammonium to straw for N, and binding to the straw and microbial uptake for P.
اظهر المزيد [+] اقل [-]Assessment of Euro 5 diesel vehicle NOx emissions by laboratory and track testing
2019
Prati, M. V. (Maria Vittoria) | Costagliola, Maria Antonietta | Zuccheroso, Andrea | Napolitano, Pierpaolo
The Volkswagen scandal has promoted experimental campaigns worldwide aimed to assess the real exhaust emissions of in-use vehicles. Attention has been paid to diesel vehicle NOx emissions that are much higher than legislative type-approval limits. This paper analysed exhaust emissions of a fleet of ten Euro 5 diesel vehicles. NOx emissions were measured during laboratory and track testing. In both cases, the type-approval test was carried out with cold and warm starts. Moreover, in the laboratory, a modified type-approval test and a real urban driving cycle were executed in order to characterise emissions in multiple operating conditions, outside of the homologation boundaries. The testing environment did not influence the emissions behaviour of the tested vehicles. Track and laboratory results, in fact, were comparable when ambient conditions were comparable. The parameter which played the main role in terms of NOx emissions is the ambient temperature, fixed at 23 °C in laboratory and not controlled on the track. Above 28 °C, NOx emissions were much higher than the approval limit (almost 600 mg/km). Moreover, warm driving cycles always introduced higher NOx emissions than cold ones, because of the partial use and/or deactivation of the EGR circuit (one of effective measures to reduce NOx formation). The ratio between warm and cold emissions ranged from 2 to 5. The engine parameter which helped explain the relationship between NOx emissions and thermal engine status was the intake air temperature. For intake air temperatures below 40 °C, NOx emissions were lower than 0.2 g/km. Above 40 °C, they suddenly increased up to almost 0.6 g/km. Another issue highlighted by the experimental results was that dynamic real driving caused the highest NOx emissions (almost 1 g/km).
اظهر المزيد [+] اقل [-]Reduction of FeII(EDTA)-NO by Mn powder in wet flue gas denitrification technology: stoichiometry, kinetics, and thermodynamics
2019
Chen, Jun | He, Jinjia | Wang, Xiaoping | Hrynsphan, Dzmitry | Wu, Jiali | Chen, Jianmeng | Yao, Jiachao
Conversion of Feᴵᴵ(EDTA)-NO or Feᴵᴵᴵ(EDTA) into Feᴵᴵ(EDTA) is a key process in a wet flue gas denitrification technology with Feᴵᴵ(EDTA) solution. In this work, the stoichiometry, kinetics, and thermodynamics of Feᴵᴵ(EDTA)-NO reduction by Mn powder were investigated. We first studied the Feᴵᴵ(EDTA)-NO reduction and product distribution to speculate a possible stoichiometry of Feᴵᴵ(EDTA)-NO reduction by Mn powder. Then, the effects of major influencing factors, such as pH value, temperature, and Mn concentration, were studied. The pseudo-second-order model was established to describe the Feᴵᴵ(EDTA)-NO reduction. Simultaneously, according to Arrhenius and Eyring-Polanyi equations, the reaction activation energy (Eₐ), enthalpy of activation (∆H‡), and entropy of activation (∆S‡) were calculated as 23.68 kJ/mol, 21.148 kJ/mol, and − 149.728 J/(k mol), respectively. Additionally, simultaneous reduction of Feᴵᴵᴵ(EDTA) and Feᴵᴵ(EDTA)-NO was investigated to better study the mechanism of Feᴵᴵ(EDTA) regeneration, suggesting that there was a competition between the two reduction processes. Finally, a simple schematic mechanism of NO absorption by Feᴵᴵ(EDTA) combined with regeneration of manganese ion and ammonium was proposed. These fundamental researches could offer a valuable guidance for wet flue gas denitrification technology with Feᴵᴵ(EDTA) solution.
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