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Cadmium Application in Tomato: Nutritional Imbalance and Oxidative Stress Полный текст
2016
Nogueirol, Roberta Corrêa | Monteiro, Francisco Antonio | Gratão, Priscila Lupino | de Alcântara da Silva, Berenice Kussumoto | Azevedo, Ricardo Antunes
Over the last few decades, the concentration of cadmium (Cd) in the environment has increased considerably in many countries due to anthropogenic activities. Cd is one of the most toxic pollutants in the environment and affects many metabolic processes in plants. The main objective of this study was to evaluate the response of the production, nutritional, and enzymatic antioxidant system of two tomato genotypes (Calabash Rouge and CNPH 0082) grown in tropical soils that were treated with doses of Cd. Soil samples were collected from the layer of earth at a depth of 0–0.2 m in areas subjected to a minimum of human disturbance. The concentrations of Cd applied to the soil samples were 0, 1, 2, and 4 times (0, 3, 6, and 12 mg kg⁻¹ of Cd) the agricultural intervention value adopted by current environmental legislation in the state of São Paulo, Brazil. Analysis of superoxide dismutase, catalase, glutathione reductase, guaiacol peroxidase, and ascorbate peroxidase activities, formation of stress indicator compound (malondialdehyde—MDA and hydrogen peroxide), parameters of production—dry mass of the shoot and root system (here in after “shoots” and “roots”), as well as nutrition, and both the bioavailable and total levels of this metal in the soil were performed. When the bioavailable content and total levels of Cd in the soil increased as a result of this metal doses applied, the biomass of both shoots and roots decreased in both genotypes (with the exception of the CNPH 0082 grown in clay soil) and displayed lower SPAD (relative chlorophyll index) values when exposed to contaminated environments with Cd concentrations. Cadmium treatment resulted in nutritional imbalances, mainly in terms of N, P, and Mn metabolism. Plants subjected to an elevated available content of metal in the soil exhibited increases in content of MDA and hydrogen peroxide and increased activity of catalase, ascorbate peroxidase, and guaiacol peroxidase in plant tissues when grown in both clay soil and sandy soil. Cadmium was phytotoxic to the plants causing a nutritional imbalance, especially on the metabolisms of N, P, and Mn. An oxidative stress condition was established in response to the Cd treatments applied, which led to changes in peroxidase activity.
Показать больше [+] Меньше [-]Toward a Cost-Efficient Method for Monitoring of Traffic-Derived Pollutants with Quartz Sand Boxes Полный текст
2016
Ojha, Gobinda | Appel, Erwin | Wawer, Małgorzata | Magiera, Tadeusz | Hu, Shouyun
This study aims at understanding characteristics of current traffic pollution at roadsides and to assess the use of magnetic parameters for a cost-efficient monitoring concept. We conducted a systematic monitoring study of roadside pollution at three sites in southern Germany and one site at Lanzhou/China. For this purpose, we installed ground-based monitoring boxes filled with clean quartz sand at different distances (1, 2, and 4 m) from the road. Mass-specific magnetic susceptibility (χ), heavy metal (HM) contents, and polycyclic aromatic hydrocarbon (PAH) concentrations all showed decreasing values with distance to the roadside. The temporal variations over 2 years of monitoring reveal an overall increasing trend but differences in depth migration due to seasonal effects (i.e., precipitation). A magnetite-like phase turned out to be responsible for the enhancement of χ. Significant positive correlations between χ and total PAHs as well as HMs for the German sites suggest that χ—which can be measured fast and convenient—can be used as a proxy for traffic-derived PAH and HM pollution. However, in the much drier region of Lanzhou, the relationship of χ with HMs is much weaker, which might be caused by specific materials used in road construction and heavy vehicles. From the obtained results, we conclude that an appropriate roadside monitoring procedure based on magnetic signatures should best use a single thin (1–2 cm) layer of clean quartz sand protected against lateral material translocation.
Показать больше [+] Меньше [-]Environmentally Relevant Concentrations of TiO2 Nanoparticles Affected Cell Viability and Photosynthetic Yield in the Chlorophyceae Scenedesmus bijugus Полный текст
2016
Barreto, DanielaMariano | Lombardi, AnaTeresa
The impact of nanoparticles (NPs) in phytoplankton is understudied, particularly with respect to the organism’s physiology and environmentally relevant concentrations. In the present research, we investigated the effects of titanium dioxide nanoparticles (nano-TiO₂) in the physiology of Scenedesmus bijugus, a freshwater cosmopolitan phytoplankter, exposed to concentrations ranging from 3.30 × 10⁻⁹ mol L⁻¹ (log −8.48) to 3.70 × 10⁻⁷ mol L⁻¹ (log −6.43), which includes environmentally relevant values. The nano-TiO₂ concentrations in the medium and in the cells were determined in experiments that lasted 96 h. Controlled environmental conditions were used throughout and a variety of endpoints were monitored. These included cell density, cell viability, chlorophyll a concentration, growth rates, maximum quantum yield of photosystem II (ΦM), intracelular proteins and carbohydrates, and proteins:carbohydrates ratios. The results showed that cell viability was the most sensitive parameter for the detection of the nano-TiO₂ effects, being followed by ΦM. At the concentration of 3.90 × 10⁻⁸ mol L⁻¹ (log −7.40), there was an increase of nano-TiO₂ injured cells, and at 3.70 × 10⁻⁷ mol L⁻¹ (log −6.43) 24%, ΦM decrease in comparison with the controls was obtained. Different from several literature results, we showed that nano-TiO₂ particles at environmentally relevant concentrations affected microalgae physiology, and this was dependent on the endpoint used to evaluate the effect.
Показать больше [+] Меньше [-]Nitrogen oxides and ozone in Portugal: trends and ozone estimation in an urban and a rural site Полный текст
2016
Fernández-Guisuraga, José Manuel | Castro, Amaya | Alves, Célia | Calvo, Ana | Alonso-Blanco, Elisabeth | Blanco-Alegre, Carlos | Rocha, Alfredo | Fraile, R. (Roberto)
This study provides an analysis of the spatial distribution and trends of NO, NO₂ and O₃ concentrations in Portugal between 1995 and 2010. Furthermore, an estimation model for daily ozone concentrations was developed for an urban and a rural site. NO concentration showed a significant decreasing trend in most urban stations. A decreasing trend in NO₂ is only observed in the stations with less influence from emissions of primary NO₂. Several stations showed a significant upward trend in O₃ as a result of the decrease in the NO/NO₂ ratio. In the northern rural region, ozone showed a strong correlation with wind direction, highlighting the importance of long-range transport. In the urban site, most of the variance is explained by the NO₂/NOX ratio. The results obtained by the ozone estimation model in the urban site fit 2013 observed data. In the rural site, the estimated ozone during extreme events agrees with observed concentration.
Показать больше [+] Меньше [-]Equilibrium and Kinetic Studies of Trihalomethanes Adsorption onto Multi-walled Carbon Nanotubes Полный текст
2016
Dehghani, Mohammad Hadi | Mohammadi, Mohammad | Mohammadi, Mahmood Ali | Mahvi, Amir Hossein | Yetilmezsoy, Kaan | Bhatnagar, Amit | Heibati, Behzad | McKay, G. (Gordon)
In the present study, multi-walled carbon nanotubes (MWCNTs) have been used for the rapid removal of four trihalomethanes (THMs) from aqueous solutions. The adsorption capacity of THMs onto MWCNTs was reasonably constant in the pH range of 5–7 but decreased as the pH exceeded 7. Four equilibrium isotherm models, namely, Langmuir, Freundlich, Temkin, and Sips, were applied to determine the best-fit equilibrium expressions. The results showed that all four experimental adsorption isotherms were best correlated by using the Sips model. The maximum adsorption capacities for the CHCl₃, CHCl₂Br, CHClBr₂, and CHBr₃ were found to be 10.98, 6.85, 6.57, and 5.95 mg/g, respectively. The rate of adsorption followed the pseudo-second-order kinetic model. Furthermore, four nonlinear regression-based equations were also derived to model THM adsorption from aqueous solutions by MWCNTs. The modeling results clearly indicated that the empirical formulations satisfactorily described the behavior of the present adsorption process for CHCl₃ (R ² = 0.949), CHCl₂Br (R ² = 0.945), CHClBr₂ (R ² = 0.936), and CHBr₃ (R ² = 0.919). The overall results confirmed that MWCNTs could be a promising adsorbent material for THMs removal from aqueous solutions.
Показать больше [+] Меньше [-]Seasonal Variability in Stormwater Quality Treatment of Permeable Pavements Situated Over Heavy Clay and in a Cold Climate Полный текст
2016
Winston, Ryan J. | Davidson-Bennett, Keely M. | Buccier, Kristen M. | Hunt, W. F. (William Frederick)
Permeable pavements mitigate the impacts of urbanization on surface waters through pollutant load reduction, both by sequestration of pollutants and stormwater volume reduction through exfiltration. This study examined the non-winter water quality performance of two side-by-side permeable pavements in the Ohio snowbelt. The permeable interlocking concrete pavements were designed to drain impervious catchments 2.2 (large) and 7.2 (small) times larger than their surface area, were located over clay soils, and incorporated the internal water storage design feature. Nutrient reduction was similar to past studies—organic nitrogen and particulate phosphorus were removed through filtration and settling, while dissolved constituents received little treatment. Because of 16 and 32 % volume reductions in the small and large installations, respectively, nutrient loads were often significantly reduced but generally by less than 50 %. Aluminum, calcium, iron, magnesium, lead, chloride, and total suspended solids (TSS) concentrations and loads often increased after passing through the permeable pavements; effluent TSS loads were three- to five-fold higher than influent TSS loads. This was apparently due to seasonal release of clay- and silt-sized particles from the soils underlying the permeable pavement and inversely related to elapsed time since winter. The application of de-icing salt is thought to have caused deflocculation of the underlying soils, allowing particulates to exit with stormwater as it discharged from the underdrain of the permeable pavements. By autumn, both permeable pavements discharged metals and TSS concentrations similar to others in the literature, suggesting the de-icing effects lasted 3–6 months post-winter. Sodium may substantially affect the performance of permeable pavements following winter de-icing salt application, particularly when 2:1 clay minerals, such as vermiculites and smectites, predominate.
Показать больше [+] Меньше [-]Temporary Increase in Sea Salt Deposition Accelerates Recovery of Brown Trout (Salmo Trutta) Populations in Very Dilute and Acidified Mountain Lakes Полный текст
2016
Enge, Espen | Auestad, Bjørn H. | Hesthagen, Trygve
We studied the recovery of brown trout populations from 1970 to 2010 in acidified mountain lakes with low ionic content in southwestern Norway. A total of 181 test fishing surveys with gill net series were performed in 59 lakes. We found that the most significant recovery occurred during the 1980s and early 1990s. In this period, only limited improvement in the water chemistry related to acidification, i.e., pH, was observed. However, due to a temporary increase in sea salt deposition, water conductivity almost doubled during this period. In many of the mountain lakes in the study area, the brown trout populations are restricted by ion deficit. Moreover, greater ionic strength ameliorates the effects of acidification by increasing the tolerance to H⁺. Well-established relationships between conductivity and the relative abundance of brown trout (CPUE) explain the observed recovery. We conclude that the dynamics of the sea salt ion contribution should be taken into consideration wherever biological recovery in very diluted water qualities is being evaluated.
Показать больше [+] Меньше [-]NH3-SCR Performance of Mn-Fe/TiO2 Catalysts at Low Temperature in the Absence and Presence of Water Vapor Полный текст
2016
Zhu, Lin | Zhong, Zhaoping | Yang, Han | Wang, Chunhua
Mn-Fe/TiO₂ catalysts synthesized by sol-gel and co-precipitation methods were used for the selective catalytic reduction (SCR) of NO with NH₃. The catalysts were characterized by N₂ physisorption, XRD, NH₃/NOₓ-TPD, and H₂-TPR. The catalytic activities for SCR and NH₃/NO oxidation were investigated in the absence and presence of water. In this study, Mn-Fe/TiO₂(S) catalyst exhibited better catalytic activity at low temperature below 175 °C in the absence of H₂O. However, more by-product of N₂O was observed in this case in contrast with Mn-Fe/TiO₂(C). The similar phenomenon was observed during the process of NH₃ catalytic oxidation. The excellent redox capability and abundant active adsorbed species on the catalyst surface accounted for higher NOₓ conversion and more N₂O formation for Mn-Fe/TiO₂(S). It was found that water vapor hindered the activation of NH₃ and adsorption-oxidation of NO, and thus, impeded catalytic activity of Mn-Fe/TiO₂ during standard SCR process at low temperature, even though it reduced the formation of N₂O. The inhibition for over dehydrogenation of amide adsorbed species and the deceleration for decomposition of ammonium nitrate species might be two reasons accounting for the decrease of N₂O concentration in the presence of H₂O. The different catalysts exhibited the different poisoning resistance to SO₂ and the SO₂ resistance of manganese-based catalyst at low temperature still needed the further improvement.
Показать больше [+] Меньше [-]Fate and Analysis of Endocrine-Disrupting Compounds in a Wastewater Treatment Plant in Portugal Полный текст
2016
Carvalho, Ana Rita | Cardoso, Vitor | Rodrigues, Alexandre | Benoliel, Maria João | Duarte, Elizabeth
This paper presents the study of the occurrence of ten endocrine-disrupting compounds in twenty wastewater samples, collected from different sampling points throughout a wastewater treatment plant process. This work was assessed using ultra-performance liquid chromatography with electrospray ionization-tandem mass spectrometry that provides simultaneous quantification and confirmation of the presence of these emerging compounds. All samples were previously cleaned with vacuum filtration and extracted by solid-phase extraction. The compounds studied in this work are 17β-estradiol, ethinylestradiol, estriol, estrone, progesterone, mestranol and diethylstilbestrol, 4-n-nonylphenol, 4-tert-octylphenol and bisphenol A. The analytical limits were calculated for each compound and were used to identify and these target compounds in a wastewater treatment plant. The main conclusions obtained during this study emphasized that wastewater is an important contamination source of these compounds, the most common being bisphenol A and nonylphenol and wastewater treatment plants are not structured to remove endocrine-disrupting compounds. However some removal efficiencies were achieved for estriol (around 98 %) and bisphenol A (around 67 %) along treatment process, indicating that with some preventive approaches it is possible to minimize this problem.
Показать больше [+] Меньше [-]How to Assess Temporal Changes of Point and Diffuse Contamination in a Rural Karstic Watershed? Relevance of Suspended Particulate Matter (SPM) for Efficient Monitoring Полный текст
2016
Chiffre, Axelle | Degiorgi, François | Morin-Crini, Nadia | Bolard, Audrey | Chanez, Etienne | Badot, Pierre-Marie
Waste water treatment plants (WWTP) have attracted attention in numerous studies in their impact on receiving surface waters because of the presence of varied contaminants in their effluents. This study investigated the relevance of particle-bound contaminants using suspended particulate matter (SPM) to monitor the temporal variability of the impact of a WWTP discharge in a chalk stream (Loue River) in France. We performed five sampling campaigns of SPM and sediment during a year at different seasons and analyzed polycyclic aromatic hydrocarbons (PAHs) and phosphorus in both matrix. PAH contents in SPM ranged from 675 to 3709 μg kg⁻¹ dry weight (dw) and in sediment from 668 to 7712 μg kg⁻¹ dw. Levels of phosphorus ranged from 364 to 1380 mg kg⁻¹ dw in SPM and from 315 to 523 mg kg⁻¹ dw in sediment. The WWTP increased significantly PAH levels in SPM to the Loue River. However, our results did not allow to evidence significant differences on particulate phosphorus concentration in SPM. Nevertheless, we evidenced significant seasonal variations of PAH and phosphorus concentrations in SPM. Besides sediment sampling, the collection of SPM allowed to monitor changes in contamination from the WWTP and highlighted impact of WWTP on PAH concentrations and changes of PAH and phosphorus concentrations over time. Contamination of SPM of the Loue River was driven by mixed inputs from point source like WWTP and from diffuse sources in the catchment like runoff from impervious and pervious surfaces. Combining monitoring of SPM and sediment proved to be an improved approach to assess contamination of local and diffuse sources in chalk streams.
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