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Результаты 3701-3710 из 4,309
Assessment of potential health risk of fluoride consumption through rice, pulses, and vegetables in addition to consumption of fluoride-contaminated drinking water of West Bengal, India Полный текст
2017
Bhattacharya, Piyal | Samal, Alok Chandra | Banerjee, Suman | Pyne, Jagadish | Santra, Subhash Chandra
A study was conducted in fluoride-affected Bankura and Purulia districts of West Bengal to assess the potential health risk from fluoride exposure among children, teenagers, and adults due to consumption of rice, pulses, and vegetables in addition to drinking water and incidental ingestion of soil by children. Higher mean fluoride contents (13–63 mg/kg dry weight) were observed in radish, carrot, onion bulb, brinjal, potato tuber, cauliflower, cabbage, coriander, and pigeon pea. The combined influence of rice, pulses, and vegetables to cumulative estimated daily intake (EDI) of fluoride for the studied population was found to be 9.5–16%. Results also showed that intake of ivy gourd, broad beans, rice, turnip, fenugreek leaves, mustard, spinach, and amaranth grown in the study area is safe at least for time being. The cumulative EDI values of fluoride (0.06–0.19 mg/kg-day) among different age group of people of the study area were evaluated to be ~10⁴ times higher than those living in the control area; the values for children (0.19 and 0.52 mg/kg-day for CTE and RME scenarios, respectively) were also greater than the “Tolerable Upper Intake Level” value of fluoride. The estimated hazard index (HI) for children (3.2 and 8.7 for CTE and RME scenarios, respectively) living in the two affected districts reveals that they are at high risk of developing dental fluorosis due to the consumption of fluoride-contaminated rice, pulses, and vegetables grown in the study area in addition to the consumption of contaminated drinking water.
Показать больше [+] Меньше [-]Activated carbon adsorptive removal of azo dye and peroxydisulfate regeneration: from a batch study to continuous column operation Полный текст
2017
The performance of activated carbon (AC) for the adsorption of Acid Orange 7 (AO7) was investigated in both batch and column studies. The optimal conditions for adsorption process in batch study were found to be a stirring speed of 500 rpm, AC dosage of 5 g/L, and initial AO7 concentration of 100 mg/L. The spent AC was then treated with peroxydisulfate (PDS), and the regenerated AC was used again to adsorb AO7. Both pseudo-first-order and pseudo-second-order rate models for adsorption kinetics were investigated, and the results showed that the latter model was more appropriate. The effects of regeneration time, PDS concentration, and stirring speed on AO7-spent AC regeneration were investigated in batch studies, and the optimal conditions were time 2 h, stirring speed 700 rpm, and PDS concentration 10 g/L. Under the same adsorption conditions, 89% AO7 could be decolorized by adsorption using regenerated AC. In the column studies, the effect of flow rate was investigated and the adsorption capacity was nearly the same when the flow rate rose from 7.9 to 11.4 mL/min, but it decreased significantly when the flow rate was increased to 15.2 mL/min. The performance of regenerated AC in the column was also investigated, and a slight increase in the adsorption capacity was observed in the second adsorption cycle. However, the adsorption capacity decreased to some extent in the third cycle due to the consumption of C-OH group on the AC surface during PDS regeneration.
Показать больше [+] Меньше [-]Removal of Cr(VI) from aqueous solution using electrosynthesized 4-amino-3-hydroxynaphthalene-1-sulfonic acid doped polypyrrole as adsorbent Полный текст
2017
Polypyrrole (PPy) conducting films, doped with 4-amino-3-hydroxynaphthalene sulfonic acid (AHNSA), were electrosynthesized by anodic oxidation of pyrrole on Pt and steel electrodes in aqueous medium (0.01 M AHNSA +0.007 M NaOH, using cyclic voltammetry (CV), and their electrochemical properties were studied. Fourier-transform infrared (FT-IR) spectroscopy confirmed the formation of AHNSA-PPy films. Their morphology was characterized by scanning electron microscopy (SEM), and their optical properties, including UV-VIS absorption and fluorescence spectra, were also investigated. AHNSA-PPy films were used for the removal of chromium(VI) from aqueous solution, by means of the immersion method and the Cr(VI) electro-reduction method. The effect of various experimental parameters, including the adsorbent (polymer) mass, pH, type of electrodes, and current intensity, on the adsorption of chromium by the polymer was performed and optimized. The adsorption and electro-reduction of (Cr VI) on the AHNSA-PPy film surface were found to be highly pH-dependent, and the kinetics of Cr(VI) adsorption and electro-reduction followed second-order kinetic curves. Apparent second-order rate constants were about three times higher for the Cr(VI) electro-reduction method than for the immersion method, indicating that the use of electro-reduction method significantly accelerated the chromium adsorption process on polymer. The maximum adsorption capacity of the AHNSA-PPy film for chromium was 224 mg g⁻¹. A 96% chromium removal from pure aqueous solution was reached within about 48 h by the immersion method, but only within about 6 h by the Cr(VI) electro-reduction method. Application of both methods to Cr(VI) fortified natural waters of Senegal led to chromium removal efficiency high values (93 to 96% according to the type of natural water).
Показать больше [+] Меньше [-]Changes of foraging patch selection and utilization by a giant panda after bamboo flowering Полный текст
2017
Li, Guochun | Song, Huadong | Altigani, Latifa A. A. | Zheng, Xueli | Bu, Shuhai
The bamboo flowering leads to the habitat fragmentation and food quality decline of a giant panda. Few empirical research has been conducted about the giant panda’s response to the bamboo flowering. Here, we investigated the characteristics of bamboo stands, giant panda’s activity, and selection and utilization of bamboo stands by giant panda in Taibaishan National Nature Reserve, China, over a 3-year period (September 2013–May 2016) during the Fargesia qinlingensis flowering period. Our results indicated that the proportion of whole bamboo stands flowering has gradually expanded from 26.7% in 2013 and 33.9% in 2014 to 52.3% in 2015. Although the flowering bamboo has lower crude protein and higher crude fiber than a non-flowering bamboo, the giant panda still fed on flowering bamboo from the evidence of droppings. The giant panda left its feeding sites and moved to the high elevation along river when the proportion of flowering reached 69.2% at elevation of 2350–2450 m in the third year. With the decline of the quality of bamboo stand of Fargesia qinlingensis, the giant panda abandoned its feeding sites when the threshold value of bamboo flowering reached 56.9–69.2%. Flexibility in foraging strategy and spatial behavior can help the giant panda to better adapt to the environment.
Показать больше [+] Меньше [-]Toxic effect of Atalantia monophylla essential oil on Callosobruchus maculatus and Sitophilus oryzae Полный текст
2017
Nattudurai, Gopal | Baskar, Kathirvelu | Paulraj, Micheal Gabrial | Islam, Villianur Ibrahim Hairul | Ignacimuthu, Savarimuthu | Duraipandiyan, Veeramuthu
The hydrodistillated essential oil of Atalantia monophylla was subjected to GC-MS. Forty compounds were presented in the essential oil. Eugenol (19.76 %), sabinene (19.57 %), 1,2-dimethoxy-4-(2-methoxyethenyl) benzene (9.84 %), beta-asarone (7.02 %) and methyl eugenol (5.52 %) were found the predominant compounds. The oil was tested for fumigant toxicity and repellent activity against Callosobruchus maculatus and Sitophilus oryzae. The development stage of C. maculatus fecundity, adult emergence and also ovicidal activities were studied by the treatment of A. monophylla oil. The oil exhibited considerable fumigation toxicity (70.22 %), repellent activity (85.24 %) and ovicidal activity (100 %) against C. maculatus. The oil significantly reduced the protein, esterase, acetylcholinesterase and glutathione S-transferase on C. maculatus and S. oryzae. It can be considered that A. monophylla has a potential insecticide against stored product pests.
Показать больше [+] Меньше [-]Degradation of 3,4-dichlorobenzotrifluoride by the Fenton-like process using zirconia-coated magnetite magnetic nanoparticles as an effective heterogeneous catalyst Полный текст
2017
Chen, Hai | Sun, Zhengnan | Yang, Zhilin | Zhang, Zhonglei | Wang, Jianlong | Feng, Mingbao | Yang, Qi
In this study, zirconia-coated magnetite magnetic nanoparticles (ZrO₂/Fe₃O₄ MNPs) were prepared, characterized, and used as an effective and reusable heterogeneous catalyst for 3,4-dichlorobenzotrifluoride (3,4-DCBTE) degradation. The catalytic potential of the Fe₃O₄/ZrO₂-H₂O₂ system for the removal of 3,4-DCBTE was tested in comparison with several other systems, and the effects of various operating parameters, including initial solution pH, catalyst addition, H₂O₂ concentrations, and reaction temperature, were also evaluated with respect to the degradation efficiency of 3,4-DCBTE. Results showed that the Fe₃O₄/ZrO₂ composite could effectively enhance the oxidation of 3,4-DCBTE by the Fenton-like process, and there might be a synergetic effect in the Fe₃O₄/ZrO₂ composite. When the mass ratio of Fe₃O₄ and ZrO₂ was 1:1, the Fe₃O₄/ZrO₂ exhibited the best catalytic activity, and the catalyst-driven Fenton process achieved high removal of 3,4-DCBTE (98.5%) and total organic carbon (TOC) (52.7%) at the operating conditions: pH 3.0, catalyst 2.0 g/L, H₂O₂ 30 mM, temperature 30 °C, and reaction time 1 h. Furthermore, five successive runs of the Fenton oxidation using the same Fe₃O₄/ZrO₂ composite resulted in the steady removal of 3,4-DCBTE, further confirming the high stability of the catalyst. In addition, the possible catalytic mechanism and degradation pathways of 3,4-DCBTE were also investigated.
Показать больше [+] Меньше [-]Alleviative effect of licorice on copper chloride-induced oxidative stress in the brain: biochemical, histopathological, immunohistochemical, and genotoxic study Полный текст
2017
Mostafa, Heba El-Sayed | Alaa-Eldin, Eman Ahmad | El-Shafei, Dalia Abdallah | Abouhashem, Nehal S.
Although copper is an essential micronutrient involved in a variety of biological processes indispensable for sustaining life, it can be toxic when administered in excess. Licorice (Glycyrrhizaglabra) has been used in Chinese folk medicine for the treatment of various disorders. Licorice has the biological capabilities of detoxication, antioxidation, and antiinfection. Here, we test the hypothesis that licorice could ameliorate copper-induced neurotoxic and genotoxic effects in adult male albino rats. For this purpose, 48 adult male albino rats were randomized into five groups: group I (8 rats), untreated control; group II (16 rats), subdivided into; vehicle control IIa (8 rats) which received 1 mL saline twice weekly intraperitoneally for 8 weeks and vehicle control IIb (8 rats) received 0.5 mL distilled water/day orally gavaged for 8 weeks; group III (8 rats), treated with licorice dissolved in 0.5 mL of distilled water, 50 mg/kg b.w./day orally gavaged for 8 weeks; group IV (8 rats), copper chloride (CuCl₂) dissolved in 0.5 mL saline, 7 mg/kg b.w. twice weekly intraperitoneal for 8 weeks; and group V (8 rats), CuCl₂ + licorice (the same previously mentioned doses) licorice extract were orally given for 10 days before treatment was initiated then followed by CuCl₂ intraperitoneally for 8 weeks. We found that CuCl₂ exposure significantly increased brain oxidative stress as manifested by elevated malondialdehyde levels, decreased reduced glutathione content, and depressed antioxidant enzyme activities in brain tissues when compared with control groups. This was accompanied by histopathological changes in the form of increased cellularity and swelling of astrocytes that showed dense eosinophilic cytoplasm, pyknotic nuclei, and multiple apoptotic bodies that associated with degenerated neurons with deep eosinophilic cytoplasm. Also, strong Bax immunoreactions in the brain were detected. Furthermore, comet assay results confirmed CuCl₂-related oxidative DNA damage. Notably, all these changes were partially ameliorated in rats treated concomitantly with licorice and CuCl₂. Our results showed that licorice exerts protective effects against CuCl₂-induced neuro- and genotoxicities. These effects may be attributed to the antioxidative property of licorice.
Показать больше [+] Меньше [-]Emission analysis on the effect of nanoparticles on neat biodiesel in unmodified diesel engine Полный текст
2017
Pandian, Amith Kishore | Ramakrishnan, Ramesh Bapu Bathey | Devarajan, Yuvarajan
Biodiesels derived from the mahua seeds are established as a promising alternative for the diesel fuel owing to its non-edible nature and improved properties. TiO₂ nanoparticle in powder form is added to neat mahua oil biodiesel (BD100) to examine its effect on emission characteristics. TiO₂ nanoparticle is chosen as an additive owing to its catalytic effect, higher surface energy, and larger surface to volume ratio. TiO₂ nanoparticle with an average size of 60 nm was synthesized by sol-gel route. TiO₂ nanoparticles are added with mahua biodiesel (BD100) at 100 and 200 ppm. Mahua oil biodiesel doped with 100 and 200 ppm of TiO₂ nanoparticles are referred as BD100T100 and BD100T200. A constant speed diesel engine is employed for the experimental trail. Engine is fueled with diesel, BD100, BD100T100, and BD100T200, respectively. Experimental result confirmed that the modified fuels (BD100T200 and BD100T100) showed a significant reduction in all the emissions. Further, the addition of TiO₂ nanoparticle (200 ppm) to mahua biodiesel gave respective reduction of 9.3, 5.8, 6.6, and 2.7% in carbon monoxide, hydrocarbon, nitrogen oxide, and smoke emissions when compared to neat mahua biodiesel.
Показать больше [+] Меньше [-]Toxic evaluations of sediments in Tokyo Bay, Japan, using Japanese medaka embryos Полный текст
2017
Uno, Seiichi | Kokushi, Emiko | Kawano, Machi | McElroy, Anne E. | Koyama, Jiro
Toxic risks of sediments collected from seven sites in Tokyo Bay were evaluated using Japanese medaka embryos. Those sediments with slight pore water were placed in grass petri dishes without overlying water. The most remarkable effect in the field sediment was to cause hatching delay in embryos, and the longest time until hatching took was 12.5 ± 1.6 days post-fertilization (dpf), although that in control group was 10.1 ± 0.7 dpf. A significant delay in hatching was observed at four sites. Because total carbon concentrations were relatively high in sediments at three of these four sites, several chemicals were expected to be residues in these sites and could cause their delay. Although extreme mortality was not observed at all sites, sediments collected from the site close to Kawasaki city induced 10 % mortality. Polycyclic aromatic hydrocarbon (PAH) concentrations were remarkably high at this site compared with other sites, and thus PAH toxicities could be causing the mortality. Concentration of heavy metals such as cadmium, copper, lead, and zinc in sediments were also determined, but no clear relationship was found between toxicities to embryos and the distribution of their concentrations.
Показать больше [+] Меньше [-]Stochastic evaluation of annual micropollutant loads and their uncertainties in separate storm sewers Полный текст
2017
Hannouche, Ali | Chebbo, G. (Ghassan) | Joannis, Claude | Gasperi, Johnny | Gromaire, Marie-Christine | Moilleron, Régis | Barraud, Sylvie | Ruban, Véronique
Stochastic evaluation of annual micropollutant loads and their uncertainties in separate storm sewers Полный текст
2017
Hannouche, Ali | Chebbo, G. (Ghassan) | Joannis, Claude | Gasperi, Johnny | Gromaire, Marie-Christine | Moilleron, Régis | Barraud, Sylvie | Ruban, Véronique
This article describes a stochastic method to calculate the annual pollutant loads and its application over several years at the outlet of three catchments drained by separate storm sewers. A stochastic methodology using Monte Carlo simulations is proposed for assessing annual pollutant load, as well as the associated uncertainties, from a few event sampling campaigns and/or continuous turbidity measurements (representative of the total suspended solids concentration (TSS)). Indeed, in the latter case, the proposed method takes into account the correlation between pollutants and TSS. The developed method was applied to data acquired within the French research project “INOGEV” (innovations for a sustainable management of urban water) at the outlet of three urban catchments drained by separate storm sewers. Ten or so event sampling campaigns for a large range of pollutants (46 pollutants and 2 conventional water quality parameters: TSS and total organic carbon (TOC)) are combined with hundreds of rainfall events for which, at least one among three continuously monitored parameters (rainfall intensity, flow rate, and turbidity) is available. Results obtained for the three catchments show that the annual pollutant loads can be estimated with uncertainties ranging from 10 to 60%, and the added value of turbidity monitoring for lowering the uncertainty is demonstrated. A low inter-annual and inter-site variability of pollutant loads, for many of studied pollutants, is observed with respect to the estimated uncertainties, and can be explained mainly by annual precipitation.
Показать больше [+] Меньше [-]Stochastic evaluation of annual micropollutant loads and their uncertainties in separate storm sewers Полный текст
2017
Hannouche, Ali | Chebbo, Ghassan | Joannis, Claude | Gasperi, Johnny | Gromaire, Marie-Christine | Moilleron, Régis | Barraud, Sylvie | Ruban, Véronique | Laboratoire Eau Environnement et Systèmes Urbains (LEESU) ; AgroParisTech-École nationale des ponts et chaussées (ENPC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12) | Eau et Environnement (IFSTTAR/GERS/EE) ; Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-PRES Université Nantes Angers Le Mans (UNAM) | Déchets Eaux Environnement Pollutions (DEEP) ; Institut National des Sciences Appliquées de Lyon (INSA Lyon) ; Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)
This article describes a stochastic method to calculate the annual pollutant loads and its application over several years at the outlet of three catchments drained by separate storm sewers. A stochastic methodology using Monte Carlo simulations is proposed for assessing annual pollutant load, as well as the associated uncertainties, from a few event sampling campaigns and/or continuous turbidity measurements (representative of the total suspended solids concentration (TSS)). Indeed, in the latter case, the proposed method takes into account the correlation between pollutants and TSS. The developed method was applied to data acquired within the French research project BINOGEV^ (innovations for a sustainable management of urban water) at the outlet of three urban catchments drained by separate storm sewers. Ten or so event sampling campaigns for a large range of pollutants (46 pollutants and 2 conventional water quality parameters: TSS and total organic carbon (TOC)) are combined with hundreds of rainfall events for which, at least one among three continuously monitored parameters (rainfall intensity, flow rate, and turbidity) is available. Results obtained for the three catchments show that the annual pollutant loads can be estimated with uncertainties ranging from 10 to 60%, and the added value of turbidity monitoring for lowering the uncertainty is demonstrated. A low inter-annual and inter-site variability of pollutant loads, for many of studied pollutants, is observed with respect to the estimated uncertainties, and can be explained mainly by annual precipitation.
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