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Результаты 2941-2950 из 4,308
Biomonitoring of atmospheric pollution: a novel approach for the evaluation of natural and anthropogenic contribution to atmospheric aerosol particles Полный текст
2017
Caggiano, Rosa | Calamita, Giuseppe | Sabia, Serena | Trippetta, Serena
The investigation of the potential natural and anthropogenic contribution to atmospheric aerosol particles by using lichen-bag technique was performed in the Agri Valley (Basilicata region, southern Italy). This is an area of international concern since it houses one of the largest European on-shore reservoirs and the biggest oil/gas pre-treatment plant (i.e., Centro Olio Val d’Agri (COVA)) within an anthropized context. In particular, the concentrations of 17 trace elements (Al, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, S, Ti, and Zn) were measured in lichen bags exposed in 59 selected monitoring points over periods of 6 months (from October 2011 to April 2012) and 12 months (from October 2011 to October 2012). The general origin of the main air masses affecting the sampling site during the study period was assessed by the back trajectories clustering calculated using the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. The results allowed the identification and characterization of the crustal material, smoke, sea salt, sulfate, and anthropogenic trace element contributions to the atmospheric aerosol particles in the study area. Finally, the application of the trend surface analysis (TSA) allowed the study of the spatial distribution of the considered contributions highlighting the existence of a continuous broad variation of these contributions in the area of interest.
Показать больше [+] Меньше [-]Impact of heavy metal contamination on oxidative stress of Eisenia andrei and bacterial community structure in Tunisian mine soil Полный текст
2017
Boughattas, Iteb | Hattab, Sabrine | Boussetta, Hamadi | Banni, Mohamed | Navarro, Élisabeth
The aims of this work were firstly to study the effect of heavy metal-polluted soils from Tunisian mine on earthworm biochemical biomarkers and on bacterial communities and therefore to analyze the interaction between earth worms and bacterial communities in these contaminated soils. For this purpose, we had introduced earthworm Eisenia andrei in six soils: one from mine spoils and five from agricultural soils, establishing a gradient of contamination. The response of worms to the presence of heavy metal was analyzed at the biochemical and transcriptional levels. In a second time, the impact of worm on bacterial community structure was investigated using automated ribosomal intergenic spacer analysis (ARISA) fingerprinting. An impact of heavy metal-contaminated soils on the oxidative status of E. andrei was observed, but this effect was dependent of the level of heavy metal contamination. Moreover, our results demonstrate that the introduction of earthworms E. andrei has an impact on bacterial community; however, the major change was observed in the less contaminated site. Furthermore, a significant correlation between earthworm oxidative status biomarkers and bacterial community structure was observed, mainly in the mine spoils. Therefore, we contribute to a better understanding of the relationships between epigenic earthworms and bacterial communities in heavy metal-contaminated soils.
Показать больше [+] Меньше [-]Modeling solubility of CO2/hydrocarbon gas in ionic liquid ([emim][FAP]) using Aspen Plus simulations Полный текст
2017
Bagchi, Bishwadeep | Sati, Sushmita | Shilapuram, Vidyasagar
The Peng-Robinson equation of state with quadratic van der Waals (vdW) mixing rule model was chosen to perform the thermodynamic calculations in Flash3 column of Aspen Plus to predict the solubility of CO₂ or any one of the hydrocarbons (HCs) among methane, ethane, propane, and butane in an ionic liquid 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([emim][FAP]). Bubble point pressure, solubility, bubble point temperature, fugacity, and partial molar volume at infinite dilution were obtained from the simulations, and enthalpy of absorption, Gibbs free energy of solvation, and entropy change of absorption were estimated by thermodynamic relations. Results show that carbon chain length has a significant effect on the bubble point pressure. Methane has the highest bubble point pressure among all the considered HCs and CO₂. The bubble point pressure and fugacity variation with temperature is different for CO₂ as compared to HCs for mole fractions above 0.2. Two different profiles are noticed for enthalpy of absorption when plotted as a function of mole fraction of gas soluble in IL. Partial molar volume of CO₂ decreases with increase in temperature in [emim][FAP], while it is increased for HCs. Bubble point temperature decreases with increase in the mole fraction of the solute. Entropy of solvation increases with temperature till a particular value followed by a decrease with further increase in temperature. Gibbs free energy change of solvation showed that the process of solubility was spontaneous.
Показать больше [+] Меньше [-]Energy transfer and kinetics in mechanochemistry Полный текст
2017
Chen, Zhiliang | Lu, Shengyong | Mao, Qiongjing | Buekens, Alfons | Wang, Yuting | Yan, Jianhua
Mechanochemistry (MC) exerts extraordinary degradation and decomposition effects on many chlorinated, brominated, and even fluorinated persistent organic pollutants (POPs). However, its application is still limited by inadequate study of its reaction kinetic aspects. In the present work, the ball motion and energy transfer in planetary ball mill are investigated in some detail. Almost all milling parameters are summarised in a single factor—total effective impact energy. Furthermore, the MC kinetic between calcium oxide/Al and hexachlorobenzene is well established and modelled. The results indicate that total effective impact energy and reagent ratio are the two factors sufficient for describing the MC degradation degree of POPs. The reaction rate constant only depends on the chemical properties of reactants, so it could be used as an important index to appraise the quality of MC additives. This model successfully predicts the reaction rate for different operating conditions, indicating that it could be suitably applied for conducting MC reactions in other reactors.
Показать больше [+] Меньше [-]Efficacy of α-lipoic acid against cadmium toxicity on metal ion and oxidative imbalance, and expression of metallothionein and antioxidant genes in rabbit brain Полный текст
2017
Saleh, Hamida M. | El-Sayed, Yasser S. | Naser, Sherif M. | Eltahawy, Abdelgawad S. | Onoda, Atsuto | Umezawa, Masakazu
To explore the protective efficacy of α-lipoic acid (ALA) against Cd-prompted neurotoxicity, young male New Zealand rabbits (Oryctolagus cuniculus) were divided randomly into four groups. Group 1 (control) received demineralized water. Group 2 (Cd) administered cadmium chloride (CdCl₂) 3 mg/kg bwt. Group 3 (ALA) administered ALA 100 mg/kg bwt. Group 4 (Cd + ALA) administered ALA 1 h after Cd. The treatments were administered orally for 30 consecutive days. Cd-induced marked disturbances in neurochemical parameters were indicated by the reduction in micro- and macro-elements (Zn, Fe, Cu, P, and Ca), with the highest reduction in Cd-exposed rabbits, followed by Cd + ALA group and then ALA group. In the brain tissues, Cd has significantly augmented the lipid hydroperoxides (LPO) and reduced the glutathione (GSH) and total antioxidant capacity (TAC), and glutathione peroxidase and glutathione S-transferase enzyme activities but had an insignificant effect on the antioxidant redox enzymes. Administration of ALA effectively restored LPO and sustained GSH and TAC contents. Moreover, Cd downregulated the transcriptional levels of Nrf2, MT3, and SOD1 genes, and upregulated that of Keap1 gene. ALA treatment, shortly following Cd exposure, downregulated Keap1, and upregulated Nrf2 and GPx1, while maintained MT3 and SOD1 mRNA gene expression in the rabbits’ brain. These data indicated the ALA effectiveness in protecting against Cd-induced oxidative stress and the depletion of cellular antioxidants in the brain of rabbits perhaps due to its antioxidant, free radical scavenging, and chelating properties.
Показать больше [+] Меньше [-]Functional group influences on the reactive azo dye decolorization performance by electrochemical oxidation and electro-Fenton technologies Полный текст
2017
da Costa Soares, Izabelle Cristina | da Silva, Djalma Ribeiro | do Nascimento, José Heriberto Oliveira | Garcia-Segura, Sergi | Martínez-Huitle, Carlos Alberto
Electrochemical water treatment technologies are highly promising to achieve complete decolorization of dyebath effluents, as demonstrated by several studies reported in the literature. However, these works are focused on the treatment of one model pollutant and generalize the performances of the processes which are not transposable since they depend on the pollutant treated. Thus, in the present study, we evaluate, for the first time, the influence of different functional groups that modify the dye structure on the electrochemical process decolorization performance. The textile azo dyes Reactive Orange 16, Reactive Violet 4, Reactive Red 228, and Reactive Black 5 have been selected because they present the same molecular basis structure with different functional groups. The results demonstrate that the functional groups that reduce the nucleophilicity of the pollutant hinder the electrophilic attack of electrogenerated hydroxyl radical. Thereby, the overall decolorization efficiency is consequently reduced as well as the decolorization rate. Moreover, the presence of an additional chromophore azo bond in the molecule enhances the recalcitrant character of the azo dyes as pollutants. The formation of a larger and more stable conjugated π system increases the activation energy required for the electrophyilic attack of •OH, affecting the performance of electrochemical technologies on effluent decolorization.
Показать больше [+] Меньше [-]Association between dietary lead intake and 10-year mortality among Chinese adults Полный текст
2017
Shi, Zumin | Zhen, Shiqi | Orsini, Nicola | Zhou, Yonglin | Zhou, Yijing | Liu, Jianghong | Taylor, Anne W.
Blood lead level is associated with increased risk of mortality, but dietary lead exposure and mortality, particularly with cancer, has not been studied in the general population. The objective of the study was to assess the association between lead intake and 10-year mortality among 2832 Chinese adults. Food intake was measured by 3-day weighed food record in 2002. We documented 184 deaths (63 cancer deaths and 70 cardiovascular disease (CVD) deaths) during 27,742 person-years of follow-up. Dietary lead intake was positively associated with cancer and all-cause mortality. Across quartiles of lead intake, hazard ratios (HRs) for cancer mortality were 1.00, 0.80 (0.33–1.92), 1.52 (0.65–3.56), and 3.00 (1.06–8.44) (p for trend 0.028). HRs for all-cause mortality were 1.00, 1.28 (0.83–1.98), 1.24 (0.78–1.97), and 2.24 (1.28–3.94) (p for trend 0.011). Each 30 μg/day increase of lead intake was associated with 25% (95% CI 3–52%) increase of all-cause mortality. There was an interaction between lead intake and hypertension in relation to CVD mortality (p for interaction 0.003): HRs conferred by every 30 μg/day of lead intake were 1.57 (0.98–2.52) and 1.06 (0.81–1.39) among those with or without hypertension. Dietary lead intake was positively related to cancer and all-cause mortality.
Показать больше [+] Меньше [-]A quarter century of biomonitoring atmospheric pollution in the Czech Republic Полный текст
2017
Suchara, Ivan | Sucharová, Julie | Holá, Marie
The Czech Republic (CZ) had extremely high emissions and atmospheric deposition of pollutants in the second half of the 1980s. Since the beginning of the 1990s, moss, spruce bark and forest floor humus have been used as bioindicators of air quality. In the first half of the 1990s, seven larger areas were found to be affected by high atmospheric deposition loads. Six of these “hot spots” were caused by industrial pollution sources, mainly situated in coal basins in the NW and NE part of the country, and one large area in the SE was affected by increased deposition loads of eroded soil particles. After restructuring of industry in CZ, these hot spots were substantially reduced or even disappeared between 1995 and 2000. Since 2000, only two larger areas with slightly increased levels of industrial pollutant deposition and a larger area affected by soil dust have repeatedly been identified by biomonitoring. The distribution of lead isotope ratios in moss showed the main deposition zones around important emission sources. Very high SO₂ emissions led to extreme acidity of spruce bark extracts (pH of about 2.3) at the end of the 1980s. The rate of increasing bark pH was strikingly similar to the rate of recovery of acid wet deposition measured at forest stations in CZ. By about 2005, when the median pH value in bark increased to about 3.2, the re-colonisation of trees by several epiphyte lichen species was observed throughout CZ. An increase in the accumulation of Chernobyl-derived ¹³⁷Cs in bark was detected at about ten sites affected by precipitation during the time when radioactive plumes crossed CZ (1986). Accumulated deposition loads in forest floor humus corresponded to the position of the moss and bark hot spots.
Показать больше [+] Меньше [-]Chemical investigation and quality of urban dew collections with dust precipitates Полный текст
2017
Odeh, Issam | Arar, Sharif | Al-Hunaiti, Afnan | Sa’aydeh, Hiyam | Hammad, Ghada | Duplissy, Jonathan | Vuollekoski, Henri | Korpela, Antti | Petäjä, Tuukka | Kulmala, Markku | Hussein, Tareq
The quality and chemical composition of urban dew collections with dust precipitates without pre-cleaning of the collecting surface WSF (white standard foil) were investigated for 16 out of 20 collected samples with collected volumes ranging from 22 to 230 ml. The collection period was from March to July 2015 at an urban area, Jubaiha, which is located in the northern part of the capital city Amman, Jordan. The obtained results indicated the predominance of Ca²⁺ and SO₄ ²⁻ ions (ratio 2.2:1) that originated from Saharan soil dust; where the collected samples were alkaline (mean pH = 7.35) with high mineralization (429.22 mg/L) exceeding the previously reported dew values in Amman-Jordan. A relocation of NaCl and to a less extent Mg²⁺ from sea to land by Saharan wind is indicated by the percent sea-salt fraction calculations (over 100 and 52, respectively). The collected samples exhibited high total organic carbon (TOC) values ranging from 11.86 to 74.60 mg/L, presence of particulate settled material with turbidity ranging from 20.10 to 520.00 NTU, and presence of undesired elements like boron (mean = 1.48 mg/L) that made it different in properties from other dew water collections at clean surfaces, and exceeding the standard limits for drinking water for these parameters set by Jordanian Drinking Water standards (JS286/2015)/WHO standard. The quality of this water is more close to that for raw or agricultural water but if it is meant to be used as potable source of water, at least sand and activated charcoal filters are needed to purify it.
Показать больше [+] Меньше [-]Protective effect of Allium sativum (garlic) aqueous extract against lead-induced oxidative stress in the rat brain, liver, and kidney Полный текст
2017
Manoj Kumar, V. | Henley, A. K. | Nelson, C. J. | Indumati, O. | Prabhakara Rao, Y. | Rajanna, S. | Rajanna, B.
The present investigation was undertaken to evaluate the ameliorative activity of Allium sativum against lead-induced oxidative stress in the brain, liver, and kidney of male rats. Four groups of male Wistar strain rats (100–120 g) were taken: group 1 received 1000 mg/L sodium acetate and group 2 was given 1000 mg/L lead acetate through drinking water for 2 weeks. Group 3 and 4 were treated with 250 mg/kg body weight/day of A. sativum and 500 mg/kg body weight/day of A. sativum, respectively, by oral intubation for a period of 2 weeks along with lead acetate. The rats were sacrificed after treatment and the brain, liver, and kidney were isolated on ice. In the brain, four important regions namely the hippocampus, cerebellum, cerebral cortex, and brain stem were separated and used for the present investigation. Blood was also drawn by cardiac puncture and preserved in heparinized vials at 4 °C for estimation of delta-aminolevulinic acid dehydratase (ALAD) activity. The results showed a significant (p < 0.05) increase in reactive oxygen species (ROS), lipid peroxidation products (LPP), total protein carbonyl content (TPCC), and lead in the selected brain regions, liver, and kidney of lead-exposed group compared with their respective controls. Blood delta-ALAD activity showed a significant (p < 0.05) decrease in the lead-exposed rats. However, the concomitant administration of A. sativum resulted in tissue-specific recovery of oxidative stress parameters namely ROS, LPP, and TPCC. A. sativum treatment also restored the blood delta-ALAD activity back to control. Overall, our results indicate that A. sativum administration could be an effective antioxidant treatment strategy for lead-induced oxidative insult.
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