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A comparative study of cambium histology of Ceiba speciosa (A. St.-Hil.) Ravenna (Malvaceae) under urban pollution 全文
2017
de Vasconcellos, Thaís Jorge | Da Cunha, Maura | Callado, Cátia Henriques
Air pollution is considered to be one of the main causes of forest decline. The cambium is responsible for increase in tree girth, and its functioning is determined by environmental pressures. This study compared cambium histology of Ceiba speciosa (A. St.-Hil.) Ravenna (Malvaceae) in polluted and preserved sites in the Atlantic Rainforest domain. Samples were obtained during periods of cambial activity and dormancy and were processed and examined according to standard light microscopy techniques. In addition to differences typically observed in cambium during periods of activity and dormancy, the fusiform initials were shorter in trees of the polluted site. Furthermore, cambial rays were shorter, but larger, in the polluted site. It should be noted that all parameters related to cambial rays showed significant differences between the study sites. This is the first report of the effects of pollution on cambial activity in a South American species. The results suggest a tolerance of C. speciosa to pollution and reveal this species to be an important biomarker for environmental monitoring studies.
显示更多 [+] 显示较少 [-]Real-time detection of organic contamination events in water distribution systems by principal components analysis of ultraviolet spectral data 全文
2017
Zhang, Jian | Hou, Dibo | Wang, Ke | Huang, Pingjie | Zhang, Guangxin | Loáiciga, Hugo
The detection of organic contaminants in water distribution systems is essential to protect public health from potential harmful compounds resulting from accidental spills or intentional releases. Existing methods for detecting organic contaminants are based on quantitative analyses such as chemical testing and gas/liquid chromatography, which are time- and reagent-consuming and involve costly maintenance. This study proposes a novel procedure based on discrete wavelet transform and principal component analysis for detecting organic contamination events from ultraviolet spectral data. Firstly, the spectrum of each observation is transformed using discrete wavelet with a coiflet mother wavelet to capture the abrupt change along the wavelength. Principal component analysis is then employed to approximate the spectra based on capture and fusion features. The significant value of Hotelling’s T² statistics is calculated and used to detect outliers. An alarm of contamination event is triggered by sequential Bayesian analysis when the outliers appear continuously in several observations. The effectiveness of the proposed procedure is tested on-line using a pilot-scale setup and experimental data.
显示更多 [+] 显示较少 [-]Presence and distribution of current-use pesticides in surface marine sediments from a Mediterranean coastal lagoon (SE Spain) 全文
2017
Moreno-González, R. | León, V. M.
The spatial and seasonal distributions of current-use pesticides (CUPs), including triazines, organophosphorus pesticides, and tributylphosphate, were characterized in surface sediments from the Mar Menor lagoon during 2009 and 2010. The impact of two flash flood events on the input of CUPs and their distribution in the lagoon were also assessed. The total (dissolved + sorbed phase) input of CUPs in the two flash floods through the El Albujón watercourse into the lagoon was estimated at 38.9 kg, of which 9.9 kg corresponded to organophosphorus pesticides and 5.5 kg to triazines. CUP distribution onto sediments was not homogeneous in the lagoon due to the different contaminant sources, sediment types, and the physicochemical and hydrodynamic conditions of the Mar Menor lagoon. Thirteen CUPs were detected in 2009 and 19 in 2010, including mainly herbicides, insecticides, and the additive tributylphosphate. Mean CUP concentrations in the lagoon were generally below 20 ng g⁻¹, except for chlorpyrifos and tributylphosphate in 2010. The highest concentrations were detected in depositional areas of the lagoon, in the area of influence of the El Albujón watercourse and other wadis with groundwater contributions such as El Mirador (north) and Los Alcázares (east) and that of marine water from El Estacio channel. In fact, the maximum concentration was detected close to El Albujón watercourse (chlorpyrifos, 102.8 ng g⁻¹ dry weight). Four herbicides, two insecticides, two fungicides, and tributylphosphate showed a risk quotient higher than 1, with that for chlorpyrifos ranging from 96 to 35,200 after flash flood events.
显示更多 [+] 显示较少 [-]Does increased salinity influence the competitive outcome of two producer species? 全文
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.
显示更多 [+] 显示较少 [-]Pilot scale nanofiltration treatment of olive mill wastewater: a technical and economical evaluation 全文
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.
显示更多 [+] 显示较少 [-]How and where to perform biomonitoring studies: different levels of toxic metal pollution are detected in the Alagados Reservoir in Southern Brazil 全文
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.
显示更多 [+] 显示较少 [-]All-printed planar photoelectrochemical cells with digitated cathodes for the oxidation of diluted aqueous pollutants 全文
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.
显示更多 [+] 显示较少 [-]Globalisation and its effect on pollution in Malaysia: the role of Trans-Pacific Partnership (TPP) agreement 全文
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.
显示更多 [+] 显示较少 [-]Discarded seeds from red pepper (Capsicum annum) processing industry as a sustainable source of high added-value compounds and edible oil 全文
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.
显示更多 [+] 显示较少 [-]Emission characteristics of PBDEs during flame-retardant plastics extruding process: field investigation and laboratorial simulation 全文
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.
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