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A comparative study of removal of fluoride from contaminated water using shale collected from different coal mines in India 全文
2016
Biswas, Gargi | Dutta, Manjari | Dutta, Susmita | Adhikari, Kalyan
Low-cost water defluoridation technique is one of the most important issues throughout the world. In the present study, shale, a coal mine waste, is employed as novel and low-cost adsorbent to abate fluoride from simulated solution. Shale samples were collected from Mahabir colliery (MBS) and Sonepur Bazari colliery (SBS) of Raniganj coalfield in West Bengal, India, and used to remove fluoride. To increase the adsorption efficiency, shale samples were heat activated at a higher temperature and samples obtained at 550 °C are denoted as heat-activated Mahabir colliery shale (HAMBS₅₅₀) and heat-activated Sonepur Bazari colliery shale (HASBS₅₅₀), respectively. To prove the fluoride adsorption onto different shale samples and ascertain its mechanism, natural shale samples, heat-activated shale samples, and their fluoride-loaded forms were characterized using scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction study, and Fourier transform infrared spectroscopy. The effect of different parameters such as pH, adsorbent dose, size of particles, and initial concentration of fluoride was investigated during fluoride removal in a batch contactor. Lower pH shows better adsorption in batch study, but it is acidic in nature and not suitable for direct consumption. However, increase of pH of the solution from 3.2 to 6.8 and 7.2 during fluoride removal process with HAMBS₅₅₀ and HASBS₅₅₀, respectively, confirms the applicability of the treated water for domestic purposes. HAMBS₅₅₀ and HASBS₅₅₀ show maximum removal of 88.3 and 88.5 %, respectively, at initial fluoride concentration of 10 mg/L, pH 3, and adsorbent dose of 70 g/L.
显示更多 [+] 显示较少 [-]Soil pH effects on the interactions between dissolved zinc, non-nano- and nano-ZnO with soil bacterial communities 全文
2016
Soil pH effects on the interactions between dissolved zinc, non-nano- and nano-ZnO with soil bacterial communities 全文
2016
Zinc oxide nanoparticles (ZnO NPs) are used in an array of products and processes, ranging from personal care products to antifouling paints, textiles, food additives, antibacterial agents and environmental remediation processes. Soils are an environment likely to be exposed to manmade nanoparticles due to the practice of applying sewage sludge as a fertiliser or as an organic soil improver. However, understanding on the interactions between soil properties, nanoparticles and the organisms that live within soil is lacking, especially with regards to soil bacterial communities. We studied the effects of nanoparticulate, non-nanoparticulate and ionic zinc (in the form of zinc chloride) on the composition of bacterial communities in soil with a modified pH range (from pH 4.5 to pH 7.2). We observed strong pH-dependent effects on the interaction between bacterial communities and all forms of zinc, with the largest changes in bacterial community composition occurring in soils with low and medium pH levels (pH 4.8 and 5.9). The high pH soil (pH 7.2) was less susceptible to the effects of zinc exposure. At the highest doses of zinc (2500 mg/kg dw soil), both nano and non-nano particulate zinc applications elicited a similar response in the soil bacterial community, and this differed significantly to the ionic zinc salt treatment. The results highlight the importance of considering soil pH in nanotoxicology studies, although further work is needed to determine the exact mechanisms controlling the toxicity and fate and interactions of nanoparticles with soil microbial communities.
显示更多 [+] 显示较少 [-]Soil pH effects on the interactions between dissolved zinc, non-nano- and nano-ZnO with soil bacterial communities 全文
2016
Read, Daniel S. | Matzke, Marianne | Gweon, Hyun S. | Newbold, Lindsay | Heggelund, Laura | Ortiz, Maria Diez | Lahive, Elma | Spurgeon, David | Svendsen, Claus
Zinc oxide nanoparticles (ZnO NPs) are used in an array of products and processes, ranging from personal care products to antifouling paints, textiles, food additives, antibacterial agents and environmental remediation processes. Soils are an environment likely to be exposed to manmade nanoparticles due to the practice of applying sewage sludge as a fertiliser or as an organic soil improver. However, understanding on the interactions between soil properties, nanoparticles and the organisms that live within soil is lacking, especially with regards to soil bacterial communities. We studied the effects of nanoparticulate, non-nanoparticulate and ionic zinc (in the form of zinc chloride) on the composition of bacterial communities in soil with a modified pH range (from pH 4.5 to pH 7.2). We observed strong pH dependent effects on the interaction between bacterial communities and all forms of zinc, with the largest changes in bacterial community composition occurring in soils with low and medium pH levels (pH 4.8 and 5.9). The high pH soil (pH 7.2) was less susceptible to the effects of zinc exposure. At the highest doses of zinc (2500 mg/kg dw soil) both nano and non-nano particulate zinc applications elicited a similar response in the soil bacterial community, and this differed significantly to the ionic zinc salt treatment. The results highlight the importance of considering soil pH in nanotoxicology studies, although further work is needed to determine the exact mechanisms controlling the toxicity and fate and interactions of nanoparticles with soil microbial communities.
显示更多 [+] 显示较少 [-]Removal of bisphenol A and some heavy metal ions by polydivinylbenzene magnetic latex particles 全文
2016
Marzougui, Zied | Chaabouni, Amel | Elleuch, Boubaker | Elaissari, Abdelhamid
In this study, magnetic polydivinylbenzene latex particles MPDVB with a core-shell structure were tested for the removal of bisphenol A (BPA), copper Cu(II), lead Pb(II), and zinc Zn(II) from aqueous solutions by a batch-adsorption technique. The effect of different parameters, such as initial concentration of pollutant, contact time, adsorbent dose, and initial pH solution on the adsorption of the different adsorbates considered was investigated. The adsorption of BPA, Cu(II), Pb(II), and Zn(II) was found to be fast, and the equilibrium was achieved within 30 min. The pH 5–5.5 was found to be the most suitable pH for metal removal. The presence of electrolytes and their increasing concentration reduced the metal adsorption capacity of the adsorbent. Whereas, the optimal pH for BPA adsorption was found 7, both hydrogen bonds and π–π interaction were thought responsible for the adsorption of BPA on MPDVB. The adsorption kinetics of BPA, Cu(II), Pb(II), and Zn(II) were found to follow a pseudo-second-order kinetic model. Equilibrium data for BPA, Cu(II), Pb(II), and Zn(II) adsorption were fitted well by the Langmuir isotherm model. Furthermore, the desorption and regeneration studies have proven that MPDVB can be employed repeatedly without impacting its adsorption capacity.
显示更多 [+] 显示较少 [-]Lead and cadmium in wild boar (Sus scrofa) in the Sierra Nevada Natural Space (southern Spain) 全文
2016
Mulero, Rocío | Cano-Manuel, Javier | Ráez-Bravo, Arián | Pérez, Jesús M. | Espinosa, José | Soriguer, Ramón | Fandos, Paulino | Granados, José E. | Romero, Diego
The aims of the present study were to investigate Pb and Cd levels in tissues of wild boar (Sus scrofa) from the Sierra Nevada Natural Space (SNNS) (southern Spain). Heavy metal concentrations in livers, kidneys and bones from 111 animals were determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Bones and kidneys were the most Pb- and Cd-contaminated tissues, respectively; Cd concentrations were 5.6 times higher in kidneys than in livers. This is the first biomonitoring study of these pollutants in wild boar tissues in the SNNS, and findings indicate that this population is chronically exposed to these heavy metals. The detected Pb and Cd concentrations were lower than those found in many studies performed in Europe on the same species.
显示更多 [+] 显示较少 [-]Visible light photocatalytic antibacterial activity of Ni-doped and N-doped TiO2 on Staphylococcus aureus and Escherichia coli bacteria 全文
2016
Ananpattarachai, Jirapat | Boonto, Yuphada | Kajitvichyanukul, Puangrat
The Ni-doped and N-doped TiO₂ nanoparticles were investigated for their antibacterial activities on Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria. Their morphological features and characteristics such as particle size, surface area, and visible light absorbing capacity were compared and discussed. Scanning electron microscopy, X-ray diffraction, and UV–visible spectrophotometry were used to characterize both materials. The inactivation of E. coli (as an example of Gram-negative bacteria) and S. aureus (as an example of Gram-positive bacteria) with Ni-doped and N-doped TiO₂ was investigated in the absence and presence of visible light. Antibacterial activity tests were conducted using undoped, Ni-doped, and N-doped TiO₂. The N-doped TiO₂ nanoparticles show higher antibacterial activity than Ni-doped TiO₂. The band gap narrowing of N-doped TiO₂ can induce more visible light absorption and leads to the superb antibacterial properties of this material. The complete inactivation time for E. coli at an initial cell concentration of 2.7 × 10⁴ CFU/mL was 420 min which is longer than the 360 min required for S. aureus inactivation. The rate of inactivation of S. aureus using the doped TiO₂ nanoparticles in the presence of visible light is greater than that of E. coli. The median lethal dose (LD50) values of S. aureus and E. coli by antibacterial activity under an 18-W visible light intensity were 80 and 350 mg/ml for N-doped TiO₂, respectively.
显示更多 [+] 显示较少 [-]Short-term arsenic exposure reduces diatom cell size in biofilm communities 全文
2016
Barral-Fraga, Laura | Morin, Soizic | Rovira, Marona D. M. | Urrea, Gemma | Magellan, Kit | Guasch, Helena
Short-term arsenic exposure reduces diatom cell size in biofilm communities 全文
2016
Barral-Fraga, Laura | Morin, Soizic | Rovira, Marona D. M. | Urrea, Gemma | Magellan, Kit | Guasch, Helena
Arsenic (As) pollution in water has important impacts for human and ecosystem health. In freshwaters, arsenate (Asⱽ) can be taken up by microalgae due to its similarity with phosphate molecules, its toxicity being aggravated under phosphate depletion. An experiment combining ecological and ecotoxicological descriptors was conducted to investigate the effects of Asⱽ (130 μg L⁻¹ over 13 days) on the structure and function of fluvial biofilm under phosphate-limiting conditions. We further incorporated fish (Gambusia holbrooki) into our experimental system, expecting fish to provide more available phosphate for algae and, consequently, protecting algae against As toxicity. However, this protection role was not fully achieved. Arsenic inhibited algal growth and productivity but not bacteria. The diatom community was clearly affected showing a strong reduction in cell biovolume; selection for tolerant species, in particular Achnanthidium minutissimum; and a reduction in species richness. Our results have important implications for risk assessment, as the experimental As concentration used was lower than acute toxicity criteria established by the USEPA.
显示更多 [+] 显示较少 [-]Short-term arsenic exposure reduces diatom cell size in biofilm communities | L'exposition à court terme à l'arsenic provoque la réduction de taille diatomique dans les communautés périphytiques 全文
2016
Barral Fraga, L. | Morin, Soizic | Rovira, M.D.M. | Urrea, G. | Magellan, K. | Guasch, H. | INSTITUTE OF AQUATIC ECOLOGY GIRONA ESP ; Partenaires IRSTEA ; Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA) | Ecosystèmes aquatiques et changements globaux (UR EABX) ; Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA) | LINCOLN UNIVERSITY BIO PROTECTION RESEARCH CENTRE LINCOLN NZL ; Partenaires IRSTEA ; Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)
[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA | International audience | Arsenic (As) pollution in water has important impacts for human and ecosystem health. In freshwaters, arsenate (AsV) can be taken up by microalgae due to its similarity with phosphate molecules, its toxicity being aggravated under phosphate depletion. An experiment combining ecological and ecotoxicological descriptors was conducted to investigate the effects of AsV (130 microg L-1 over 13 days) on the structure and function of fluvial biofilm under phosphate-limiting conditions. We further incorporated fish (Gambusia holbrooki) into our experimental system, expecting fish to provide more available phosphate for algae and, consequently, protecting algae against As toxicity. However, this protection role was not fully achieved. Arsenic inhibited algal growth and productivity but not bacteria. The diatom community was clearly affected showing a strong reduction in cell biovolume; selection for tolerant species, in particular Achnanthidium minutissimum; and a reduction in species richness. Our results have important implications for risk assessment, as the experimental As concentration used was lower than acute toxicity criteria established by the USEPA.
显示更多 [+] 显示较少 [-]Performance of a pilot-scale wet electrostatic precipitator for the control of sulfuric acid mist 全文
2016
Huang, Jiayu | Wang, Hongmei | Shi, Yingjie | Zhang, Fan | Dang, Xiaoqing | Zhang, Hui | Shuyun, | Deng, Shuang | Liu, Yu
The use of a wet electrostatic precipitator (WESP) is often regarded as a viable option to reduce sulfuric acid mist emitted from the wet flue gas desulfurization (WFGD) tower in coal-fired power plants. In this study, a pilot-scale wet electrostatic precipitator equipped with a wall-cooled collection electrode is investigated for the control of sulfuric acid mist from a simulated WFGD system. The results show that due to partial charging effect, the removal efficiency of sulfuric acid aerosol decreases when the aerosol size decreases to several tens of nanometers. Moreover, due to the plasma-induced effect, a large number of ultrafine sulfuric acid aerosols below 50 nm formed at a voltage higher than 24 kV inside the WESP. The percentages of submicron-sized aerosols significantly increase together with the voltage. To minimize the adverse plasma-induced effect, a WESP should be operated at a high gas velocity with an optimum high voltage. Even at a high flue gas velocity of 2.3 m s⁻¹, the mass concentration and the total number concentration of uncaptured sulfuric acid aerosols at the WESP outlet are as low as ca. 0.6 mg m⁻³ and ca. 10⁴ 1 cm⁻³ at 28 kV, respectively. The corresponding removal efficiencies were respectively higher than 99.4 and 99.9 % and are very similar to that at 1.1 and 1.6 m s⁻¹. Moreover, the condensation-induced aerosol growth enhances the removal of sulfuric acid mist inside a WESP and enables a low emission concentration of ca. 0.65 mg m⁻³ with a corresponding removal efficiency superior to 99.4 % even at a low voltage of 21 kV, and of ca. 0.35 mg m⁻³ with a corresponding removal efficiency superior to 99.6 % at a higher voltage level of 26 kV.
显示更多 [+] 显示较少 [-]Short-term effects of atmospheric particulate matter on myocardial infarction: a cumulative meta-analysis 全文
2016
Cai, Xianlei | Li, Zhenhong | Scott, E Marian | Li, Xiuyang | Tang, Mengyao
Atmospheric particulate matter (PM) is hypothesized to increase the risk of myocardial infarction (MI). However, the epidemiological evidence is inconsistent. We identified 33 studies with more than 4 million MI patients and applied meta-analysis and meta-regression to assess the available evidence. Twenty-five studies presented the effects of the PM level on hospitalization for MI patients, while eight studies showed the effects on mortality. An increase in PM₁₀ was associated with hospitalization and mortality in myocardial infarction patients (RR per 10 μg/m³ = 1.011, 95 % CI 1.006–1.016; RR per 10 μg/m³ = 1.008, 95 % CI 1.004–1.012, respectively); PM₂.₅ also increased the risk of hospitalization and mortality in MI patients (RR per 10 μg/m³ = 1.024, 95 % CI 1.007–1.041 for hospitalization and RR per 10 μg/m³ = 1.012, 95 % CI 1.010–1.015 for mortality). The results of the cumulative meta-analysis indicated that PM₁₀ and PM₂.₅ were associated with myocardial infarctionwith the addition of new studies each year. In conclusion, short-term exposure to high PM₁₀ and PM₂.₅ levels revealed to increase risk of hospitalization and mortality for myocardial infarction. Policy support of pollution control and individual protection was strongly recommended.
显示更多 [+] 显示较少 [-]Geochemistry of the Adige River water from the Eastern Alps to the Adriatic Sea (Italy): evidences for distinct hydrological components and water-rock interactions 全文
2016
Natali, C. | Bianchini, G. | Marchina, C. | Knöller, K.
The Adige River flows from the Eastern Alps to the Adriatic Sea and the understanding of its fluvial dynamics can be improved by geochemical and O-H isotopic investigation. The most negative isotopic compositions are recorded close to the source (δ¹⁸O between −14.1 and −13.8 ‰, δD between −100.3 and −97.0 ‰), and δD and δ¹⁸O values generally increase downstream through the upper part (UP, the mountainous sector), stabilizing along the lower part (LP, the alluvial plain) of the river with δ¹⁸O between −12.4 and −11.8 ‰, δD between −86.9 and −83.7 ‰. The isotopic variations along the stream path (δ¹⁸O-δD vs distance from the source) depict subparallel distributions for all the investigated periods, with less negative values recorded in winter. Total dissolved solids (TDS) concentration shows the lowest value (<100 mg/l) at the river source, jumping to 310 mg/l at the Rio Ram inflow, then decreasing down to the Isarco River confluence; from here, we observed an increase toward the river mouth, with different values in the distinct sampling periods. The lowest values (140–170 mg/l) were recorded during high discharge in spring, whereas higher TDS values (up to 250 mg/l) were recorded during winter low flow conditions. Extreme TDS values were observed in the estuarine samples (up to 450 mg/l), as result of mixing with seawater. The results allow for the identification of distinct water end-members: glacio-nival component(s) characterized by the most negative isotopic composition and extremely low TDS, a rainfall component characterized by intermediate isotopic and elemental composition and groundwater characterized by the less negative isotopic composition and comparatively higher TDS. An additional component is represented by seawater, which is recorded at the lowest reach of the river during drought periods. These contributions variously mix along the stream path in the distinct hydrological periods, and the presented data are a snapshot of the current hydroclimatic conditions. Future investigations will evaluate possible hydrological variations related to meteo-climatic changes. Monitoring is fundamental for future water management to overcome the vanishing of a significant water end-member of the basin, i.e., the glacio-nival reservoir that is severely affected by the ongoing climatic changes.
显示更多 [+] 显示较少 [-]Exposure to occupational air pollution and cardiac function in workers of the Esfahan Steel Industry, Iran 全文
2016
Golshahi, Jafar | Sadeghi, Masoumeh | saqira, Mohammad | Zavar, Reihaneh | Sadeghifar, Mostafa | Roohafza, Hamidreza
Air pollution is recognized as an important risk factor for cardiovascular disease. We investigated association of exposure to occupational air pollution and cardiac function in the workers of the steel industry. Fifty male workers of the agglomeration and coke-making parts of the Esfahan Steel Company were randomly selected (n = 50). Workers in the administrative parts were studied as controls (n = 50). Those with known history of hypertension, dyslipidemia, or diabetes, and active smokers were not included. Data of age, body mass index, employment duration, blood pressure, fasting blood sugar, and lipid profile were gathered. Echocardiography was performed to evaluate cardiac function. Left ventricular ejection fraction was lower in workers of the agglomeration/coke-making parts than in controls (mean difference = 5 to 5.5 %, P < 0.001). Mild right ventricular dilatation and grade I pulmonary hypertension were present in three (12 %) workers of the coke-making part, but none of the controls (P = 0.010). According to these results, occupational air pollution exposure in workers of the steel industry is associated with left heart systolic dysfunction. Possible right heart insults due to air pollution exposure warrant further investigations.
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