Уточнить поиск
Результаты 2451-2460 из 2,512
Abatement of spinosad and indoxacarb residues in pure water by photocatalytic treatment using binary and ternary oxides of Zn and Ti Полный текст
2014
Fenoll, J. | Vela, N. | Garrido, I. | Pérez-Lucas, G. | Navarro, S.
The photodegradation of indoxacarb, a broad spectrum foliar insecticide and spinosad, a natural insecticide containing two active ingredients, spinosyn A (major component) and spinosyn D (minor component), was studied in aqueous suspensions of binary (ZnO and TiO₂) and ternary (Zn₂TiO₄ and ZnTiO₃) oxides under artificial light (300–460 nm) irradiation. As expected, the influence of the semiconductor materials on the degradation of both was very significant in all cases. Photocatalytic experiments showed that the addition of semiconductors in tandem with Na₂S₂O₈ as electron acceptor strongly improved the removal of indoxacarb and spinosad in water compared with the photolytic tests. The reaction rates significantly increased, especially for the ZnO/Na₂S₂O₈ and TiO₂/Na₂S₂O₈ systems. The first-order equation (monophasic model) satisfactorily explained the disappearance process, although it offered no explanation for the small concentrations remaining in the process.
Показать больше [+] Меньше [-]Using Bayesian optimization method and FLEXPART tracer model to evaluate CO emission in East China in springtime Полный текст
2014
Pan, X. L. | Kanaya, Y. | Wang, Z. F. | Tang, X. | Takigawa, M. | Pakpong, P. | Taketani, F. | Akimoto, H.
Carbon monoxide (CO) is of great interest as a restriction factor for pollutants related to incomplete combustions. This study attempted to evaluate CO emission in East China using the analytical Bayesian inverse method and observations at Mount Hua in springtime. The mixing ratio of CO at the receptor was calculated using 5-day source-receptor relationship (SRR) simulated by a Lagrangian Particle Dispersion Model (FLEXPART) and CO emission flux. The stability of the inversion solution was evaluated on the basis of repeated random sampling simulations. The inversion results demonstrated that there were two city cluster regions (the Beijing–Tianjin–Hebei region and the low reaches of the Yangtze River Delta) where the difference between a priori (Intercontinental Chemical Transport Experiment-Phase B, INTEX-B) and a posteriori was statistically significant and the a priori might underestimate the CO emission flux by 37 %. A correction factor (a posteriori/a priori) of 1.26 was suggested for CO emission in China in spring. The spatial distribution and magnitude of the CO emission flux were comparable to the latest regional emission inventory in Asia (REAS2.0). Nevertheless, further evaluation is still necessary in view of the larger uncertainties for both the analytical inversion and the bottom-up statistical approaches.
Показать больше [+] Меньше [-]Development of aquatic life criteria in China: viewpoint on the challenge Полный текст
2014
Jin, Xiaowei | Wang, Yeyao | Giesy, John P. | Richardson, Kristine L. | Wang, Zijian
While more developed countries have a well-established systems to develop water quality criteria (WQC), little research has been done on the adequacy of the current WQC to protect endemic species of China. In order to maintain the health of aquatic ecosystems in China, a series of projects to establish national WQC based on regional characteristics has recently been initiated. However, the establishment of a completely novel methodology would be costly and time consuming. Also, due to the similarities in physiologies and natural histories of classes of aquatic organisms, there is no reason to believe that WQC would not be sufficient to protect unique species in China. This review was undertaken to identify key outstanding issues regarding establishment of aquatic life criteria (ALC) to be applied in China, including prioritization of chemicals, test species, mode of action, field/semi-field data, and methods of aggregating the information and calculating the ALC. This was used to identify the principle issues that need to be addressed in order to better understand the methods for development of criteria for the protection of aquatic life and provide a reference to China and other developing countries committed to the establishment of their own WQC system.
Показать больше [+] Меньше [-]Function of bacterial cells and their exuded extracellular polymeric substances (EPS) in virus removal by red soils Полный текст
2014
Zhao, Bingzi | Jiang, Yan | Jin, Yan | Zhang, Jiabao
The potential influence of autochthonous microorganisms on virus fate in soil is usually determined through extreme conditions of sterilization vs. nonsterilization; however, the relative importance of microbial cells and their exudates remains unclear. In this study, bacterial cells (cell) were harvested, and their exuded extracellular polymeric substances (EPS) were extracted from three strains of bacteria, namely, Gram-negative bacteria Pseudomonas putida and Pseudomonas aeruginosa as well as Gram-positive bacterium Bacillus subtilis. This study aimed to evaluate virus removal in solutions in the presence of cell, EPS, and their combination (cell/EPS), as well as to investigate how their presence affects virus removal efficiencies by four red soils based on batch experiments. Results showed that virus removal percentage in solutions ranged from 11 to 23 in the presence of cells only and from 12 to 15 in the presence of EPS only. The removal percentage in the combined cell/EPS treatment can be estimated by summing the results achieved by the cell and EPS treatments, separately. Meanwhile, cell presence had a negligible effect on virus removal by red soils. EPS and combined cell/EPS significantly reduced virus removal by 20 to 69 % and 16 to 50 %, respectively, which indicated that EPS served a dominant function in reducing virus removal. This study clearly demonstrated that the prediction of virus removal by red soils must consider the effect of bacteria, especially those producing large quantities of EPS, which can be responsible for the underestimation of viral load in certain studies.
Показать больше [+] Меньше [-]Simultaneous decontamination of cross-polluted soils with heavy metals and PCBs using a nano-metallic Ca/CaO dispersion mixture Полный текст
2014
Mallampati, Srinivasa Reddy | Mitoma, Yoshiharu | Okuda, Tetsuji | Sakita, Shogo | Simion, Cristian
In the present work, we investigated the use of nano-metallic calcium (Ca) and calcium oxide (CaO) dispersion mixture for the simultaneous remediation of contaminated soils with both heavy metals (As, Cd, Cr, and Pb) and polychlorinated biphenyls (PCBs). Regardless of soil moisture content, nano-metallic Ca/CaO dispersion mixture achieved about 95–99 % of heavy metal immobilization by a simple grinding process. During the same treatment, reasonable PCB hydrodechlorination efficiencies were obtained (up to 97 %), though higher hydrodechlorination efficiency by preliminary drying of soil was observed.
Показать больше [+] Меньше [-]A new device for formaldehyde and total aldehydes real-time monitoring Полный текст
2014
Sassine, Maria | Picquet-Varrault, Bénédicte | Perraudin, Emilie | Chiappini, Laura | Doussin, Jean François | George, Christian
A new sensitive technique for the quantification of formaldehyde (HCHO) and total aldehydes has been developed in order to monitor these compounds, which are known to be involved in air quality issues and to have health impacts. Our approach is based on a colorimetric method where aldehydes are initially stripped from the air into a scrubbing solution by means of a turning coil sampler tube and then derivatised with 3-methylbenzothiazolinone-2-hydrazone in acid media (pH = −0.5). Hence, colourless aldehydes are transformed into blue dyes that are detected by UV–visible spectroscopy at 630 nm. Liquid core waveguide LCW Teflon® AF-2400 tube was used as innovative optical cells providing a HCHO detection limit of 4 pptv for 100 cm optical path with a time resolution of 15 min. This instrument showed good correlation with commonly used techniques for aldehydes analysis such as DNPH derivatisation chromatographic techniques with off-line and on-line samplers, and DOAS techniques (with deviation below 6 %) for both indoor and outdoor conditions. This instrument is associated with simplicity and low cost, which is a prerequisite for indoor monitoring.
Показать больше [+] Меньше [-]A Cr(VI)-reducing Microbacterium sp. strain SUCR140 enhances growth and yield of Zea mays in Cr(VI) amended soil through reduced chromium toxicity and improves colonization of arbuscular mycorrhizal fungi Полный текст
2014
Soni, Sumit K. | Singh, Rakshapal | Awasthi, Ashutosh | Kalra, Alok
Pot culture experiments were conducted in a glasshouse to evaluate the effects of four efficient Cr(VI)-reducing bacterial strains (SUCR44, SUCR140, SUCR186, and SUCR188) isolated from rhizospheric soil, and four arbuscular mycorrhizal fungi (AMF—Glomus mosseae, G. aggregatum, G. fasciculatum, and G. intraradices) alone or in combination, on Zea mays in artificially Cr(VI)-amended soil. Presence of a strain of Microbacterium sp. SUCR140 reduced the chromate toxicity resulting in improved growth and yields of plants compared to control. The bioavailability of Cr(VI) in soil and its uptake by the plant reduced significantly in SUCR140-treated plants; the effects of AMF, however, either alone or in presence of SUCR140 were not significant. On the other hand, presence of AMF significantly restricted the transport of chromium from root to the aerial parts of plants. The populations of AMF chlamydospores in soil and its root colonization improved in presence of SUCR140. This study demonstrates the usefulness of an efficient Cr(VI)-reducing bacterial strain SUCR140 in improving yields probably through reducing toxicity to plants by lowering bioavailability and uptake of Cr(VI) and improving nutrient availability through increased mycorrhizal colonization which also restricted the transport of chromium to the aerial parts.
Показать больше [+] Меньше [-]Protective effect of Syzygium cumini against pesticide-induced cardiotoxicity Полный текст
2014
Atale, Neha | Gupta, Khushboo | Rani, Vibha
Pesticide-induced toxicity is a serious issue which has resulted in plethora of diseases all over the world. The organophosphate pesticide malathion has caused many incidents of poisoning such as cardiac manifestations. The present study was designed to evaluate the effect of Syzygium cumini on malathion-induced cardiotoxicity. Dose optimization of malathion and polyphenols such as curcumin, (−)-epicatechin, gallic acid, butylated hydroxyl toluene, etc. was done by MTT cell proliferation assay. Nuclear deformities, ROS production, and integrity of extra cellular matrix components were analyzed by different techniques. S. cumini methanolic pulp extract (MPE), a naturally derived gallic acid-enriched antioxidant was taken to study its effect on malathion-induced toxicity. Nuclear deformities, ROS production, and integrity of extra cellular matrix components were also analyzed. Twenty micrograms per milliliter LD50 dose of malathion was found to cause stress-mediated responses in H9C2 cell line. Among all the polyphenols, gallic acid showed the most significant protection against stress. Gallic acid-enriched methanolic S. cumini pulp extract (MPE) showed 59.76 % ± 0.05, 81.61 % ± 1.37, 73.33 % ± 1.33, 77.19 % ± 2.38 and 64.19 % ± 1.43 maximum inhibition for DPPH, ABTS, NO, H₂O₂and superoxide ion, respectively, as compared to ethanolic pulp extract and aqueous pulp extract. Our study suggests that S. cumini MPE has the ability to protect against the malathion-mediated oxidative stress in cardiac myocytes.
Показать больше [+] Меньше [-]Impact of clay mineral on air oxidation of PAH-contaminated soils Полный текст
2014
Biache, Coralie | Kouadio, Olivier | Lorgeoux, Catherine | Faure, Pierre
This work investigated the impact of a clay mineral (bentonite) on the air oxidation of the solvent extractable organic matters (EOMs) and the PAHs from contaminated soils. EOMs were isolated from two coking plant soils and mixed with silica sand or bentonite. These samples, as well as raw soils and bentonite/soil mixtures, were oxidized in air at 60 and 100 °C for 160 days. Mineralization was followed by measuring the CO₂produced over the experiments. EOM, polycyclic aromatic compound (PAC), including PAH, contents were also determined. Oxidation led to a decrease in EOM contents and PAH concentrations, these diminutions were enhanced by the presence of bentonite. Transfer of carbon from EOM to insoluble organic matter pointed out a condensation phenomenon leading to a stabilization of the contamination. Higher mineralization rates, observed during the oxidation of the soil/bentonite mixtures, seem to indicate that this clay mineral had a positive influence on the transformation of PAC into CO₂.
Показать больше [+] Меньше [-]Influence of nutrition in PCB-induced vascular inflammation Полный текст
2014
Petriello, Michael C. | Newsome, Bradley | Hennig, Bernhard
The nutritional profile of an individual can influence the toxicity of persistent environmental toxicants. Polychlorinated biphenyls (PCBs), prevalent environmental pollutants, are highly lipid-soluble toxic compounds that biomagnify through trophic levels and pose cancer, neurocognitive, and atherosclerotic risk to human populations. There is a growing body of knowledge that PCBs can initiate inflammatory responses in vivo, and this inflammation can be either exacerbated or ameliorated by nutrition. Data indicate that diets high in certain dietary lipids such as omega-6 fatty acids can worsen PCB-induced vascular toxicity while diets enriched with bioactive food components such as polyphenols and omega-3 polyunsaturated fatty acids can improve the toxicant-induced inflammation. There is evidence that bioactive nutrients protect through multiple cell signaling pathways, but we have shown that lipid raft caveolae and the antioxidant defense controller nuclear factor (erythroid-derived 2)-like 2 (Nrf2) both play a predominant role in nutritional modulation of PCB-induced vascular toxicity. Interestingly, there appears to be an intimate cross-talk between caveolae-related proteins and cellular Nrf2, and focusing on the use of specific bioactive food components that simultaneously alter both pathways may produce a more effective and efficient cytoprotective response to toxicant exposure. The use of nutrition as a protective tool is an economically beneficial means to address the toxicity of persistent environmental toxicants and may become a sensible means to protect human populations from PCB-induced vascular inflammation and associated chronic diseases.
Показать больше [+] Меньше [-]