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Pseudomorphs of barite and biogenic ZnS after phyto-crystals of calcium oxalate (whewellite) in the peat layer of a poor fen Texte intégral
2014
Smieja-Król, Beata | Janeczek, Janusz | Wiedermann, Jerzy
Pseudomorphs of barite (BaSO₄) and Cd-rich ZnS after whewellite (CaC₂O₄·H₂O) occur within remnants of Scots pine bark tissues in the peat layer of a poor fen located near a zinc smelter in south Poland. A two-step formation of the pseudomorphs is postulated based on SEM observations: (1) complete dissolution of whewellite, possibly caused by oxalotrophic bacteria, and (2) subsequent bacterially induced precipitation of barite and spheroidal aggregates of ZnS together with galena (PbS) in voids left by the dissolved whewellite crystals. Local increase in pH due to microbial degradation of whewellite, elevated concentrations of Zn(II) and Ba(II) in pore water due to the decomposition of atmospheric particles of sphalerite and barite in the acidic (pH 3.5–3.8) environment, oxidation of S species during drying and rewetting of the peat layer, and subsequent partial reduction of sulfate anions by sulfur-reducing bacteria were all factors likely involved in the crystallization of ZnS and barite in the microenvironment of the post-whewellite voids.
Afficher plus [+] Moins [-]Using of “pseudo-second-order model” in adsorption Texte intégral
2014
Ho, Yuh-Shan
A research paper's contribution exists not only in its originality and creativity but also in its continuity and development for research that follows. However, the author easily ignores it. Citation error and quotation error occurred very frequently in a scientific paper. Numerous researchers use secondary references without knowing the original idea from authors. Sulaymon et al. (Environ Sci Pollut Res 20:3011–3023, 2013) and Spiridon et al. (Environ Sci Pollut Res 20:6367–6381, 2013) presented wrong pseudo-second-order models in Environmental Science and Pollution Research, vol. 20. This comment pointed the errors of the kinetic models and offered information for citing original idea of pseudo-second-order kinetic expression. In order to stop the proliferation of the mistake, it is suggested to cite the original paper for the kinetic model which provided greater accuracy and more details about the kinetic expression.
Afficher plus [+] Moins [-]Remediation of phenanthrene-contaminated soil by simultaneous persulfate chemical oxidation and biodegradation processes Texte intégral
2014
Mora, Verónica C. | Madueño, Laura | Peluffo, Marina | Rosso, Janina A. | Del Panno, María T. | Morelli, Irma S.
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous compounds with carcinogenic and/or mutagenic potential. To address the limitations of individual remediation techniques and to achieve better PAH removal efficiencies, the combination of chemical and biological treatments can be used. The degradation of phenanthrene (chosen as a model of PAH) by persulfate in freshly contaminated soil microcosms was studied to assess its impact on the biodegradation process and on soil properties. Soil microcosms contaminated with 140 mg/kgDRY SOILof phenanthrene were treated with different persulfate (PS) concentrations 0.86–41.7 g/kgDRY SOILand incubated for 28 days. Analyses of phenanthrene and persulfate concentrations and soil pH were performed. Cultivable heterotrophic bacterial count was carried out after 28 days of treatment. Genetic diversity analysis of the soil microcosm bacterial community was performed by PCR amplification of bacterial 16S rDNA fragments followed by denaturing gradient gel electrophoresis (DGGE). The addition of PS in low concentrations could be an interesting biostimulatory strategy that managed to shorten the lag phase of the phenanthrene biological elimination, without negative effects on the physicochemical and biological soil properties, improving the remediation treatment.
Afficher plus [+] Moins [-]Speciation of non-methane hydrocarbons (NMHCs) from anthropogenic sources in Beirut, Lebanon Texte intégral
2014
Salameh, T. | Afif, C. | Sauvage, S. | Borbon, A. | Locoge, N.
The chemical composition of emissions from the different anthropogenic sources of non-methane hydrocarbons (NMHC) is essential for modeling and source apportionment studies. The speciated profiles of major NMHC sources in Lebanon, including road transport, gasoline vapor, power generation, and solvent use were established. Field sampling have been carried out by canisters in 2012. Around 67 NMHC (C2 to C9) were identified and quantified by using a gas chromatograph equipped with a flame ionization detector. Typical features of the roadway emissions included high percentages of isopentane, butane, toluene, xylenes, ethylene, and ethyne. Gasoline evaporation profiles included high percentage of the C4–C5 saturated hydrocarbons reaching 59 %. The main compounds of the power generator emissions are related to combustion. Toluene and C8–C9 aromatics were the most abundant species in emissions from paint applications. Finally, the impact of the use of region-specific source profile is tackled regarding the implication on air quality.
Afficher plus [+] Moins [-]Synthesis and characterization of nanocrystalline TiO2 with application as photoactive coating on stones Texte intégral
2014
Bergamonti, Laura | Alfieri, Ilaria | Franzò, Marco | Lorenzi, Andrea | Montenero, Angelo | Predieri, Giovanni | Raganato, Marina | Calia, Angela | Lazzarini, Laura | Bersani, Danilo | Lottici, Pier Paolo
Self-cleaning photocatalytic coatings for biocalcarenite stones, based on TiO₂nanoparticles obtained by sol–gel processes at different pH values and also adding gold particles, have been investigated. The selected test material is a biocalcarenite named “pietra di Lecce” (Lecce stone), outcropping in Southern Italy. Scanning electron microscopy with energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, and Raman investigations were carried out to characterize the TiO₂nanoparticles and coatings. Nanocrystalline anatase and, to a lesser extent, brookite phases are obtained. Photocatalytic activity of the TiO₂sols and of the coatings on “pietra di Lecce” was assessed under ultraviolet irradiation, monitoring methyl orange (MeO) dye degradation as a function of time. To evaluate the harmlessness of the treatment, colorimetric tests and water absorption by capillarity were performed. The results show good photodegradation rates for titania nanosols, particularly when putting in Au particles, whereas a satisfactory chromatic compatibility between the sol and the surface of the calcarenite is found only without Au addition. HIGHLIGHTS: Sols of nanocrystalline titania at different pH values and with Au particles were prepared and characterized. Satisfactory photodegradation of MeO by the sols in solution and on calcarenite-coated surfaces is obtained. The addition of Au particles improves the photodegradation activity but gives poor chromatic results on “pietra di Lecce”.
Afficher plus [+] Moins [-]Extraction of Sudan dyes from environmental water by hemimicelles-based magnetic titanium dioxide nanoparticles Texte intégral
2014
Li, Chenyu | Chen, Ligang | You, Xiaoxiao
A novel method for the extraction of Sudan dyes including Sudan I, II, III, and IV from environmental water by magnetic titanium dioxide nanoparticles (Fe₃O₄@TiO₂) coated with sodium dodecylsulfate (SDS) as adsorbent was reported. Fe₃O₄@TiO₂ was synthesized by a simple method and was characterized by transmission electron microscopy, Fourier-transform infrared spectrometry, and vibrating sample magnetometer. The magnetic separation was quite efficient for the adsorption and desorption of Sudan dyes. The effect of the amount of SDS, extraction time, pH, desorption condition, maximal extraction volume, and humic acid on the extraction process were investigated. This method was employed to analyze three environmental water samples. The results demonstrated that our proposed method had wide linear range (25–5,000 ng L⁻¹) with a good linearity (R ² > 0.999) and low detection limits (2.9–7.3 ng L⁻¹). An enrichment factor of 1,000 was achieved. In all three spiked levels (25, 250, and 2,500 ng L⁻¹), the recoveries of Sudan dyes were in the range of 86.9–93.6 %. The relative standard deviations obtained were ranging from 2.5 to 9.3 %. That is to say, the new method was fast and effective for the extraction of Sudan dye from environmental water.
Afficher plus [+] Moins [-]Human health risk from organ-specific accumulation of toxic metals and response of antioxidants in edible fish species from Chenab River, Pakistan Texte intégral
2014
Waheed, Sidra | Kamal, Atif | Malik, Riffat Naseem
In the current study, the bioaccumulation of essential and nonessential metals and related antioxidant activity were analyzed in three organs (muscle, gills, and liver) of herbivorous (HF) and carnivorous (CF) edible fish of Chenab River. The comparative analysis revealed a more heterogeneous accumulation of metals in the muscles of HF fish than that of CF fish [chromium (Cr, 3.4 μg g⁻¹), cobalt (Co, 1.7 μg g⁻¹), copper (Cu, 3 μg g⁻¹), and iron (Fe, 45 μg g⁻¹) versus Cr (1.3 μg g⁻¹), Co (0.1 μg g⁻¹), Cu (1.1 μg g⁻¹), and Fe (33 μg g⁻¹), respectively, P < 0.001]. These results implied an organ-specific accumulation of metals at different trophic levels. According to logistic regression analysis, the bioaccumulation of metals had marked differences in HF and CF. The antioxidant activity was significantly related to the tissue type and the metals to which the organs are exposed to. The liver of CF fish had a higher activity of antioxidant superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and lipid peroxidase (LPO) than that of HF (P < 0.05). LPO and guaiacol peroxidase (POD) in both groups were associated with a number of metals, but in HF, cadmium (Cd), Cr, Pb, and Zn were more related with the LPO and SOD activities. Moreover, Cd, Co, Fe, Pb, Ni, Cu, and Zn were above the permissible limits set by various agencies. In numerous cases, our results were even higher than those previously reported in the literature. The results provide an insight into the pollution pattern of Chenab River. These results may be helpful in the future to identify biomarkers of exposure in aquatic organisms.
Afficher plus [+] Moins [-]Development and implementation of surface water quality standards for protection of human health in Korea Texte intégral
2014
An, Youn-Joo | Kwak, Jin II | Nam, Sun-Hwa | Jung, Myung-sook
Current water quality standards for the protection of human health in Korea include 17 substances found in rivers and streams. Due to increasing concern over the release of hazardous chemicals into the aquatic environment, there has been a demand for additional water quality standards. Therefore, the Korean Ministry of the Environment plans to gradually increase the number of water quality standards to 30 substances, including 22 substances for protection of human health and 8 substances for protection of aquatic ecosystems by 2015. In this study, new water quality standards for protection of human health were established for 1,4-dioxane, formaldehyde, and hexachlorobenzene. We selected candidate hazardous chemicals, conducted a human health risk assessment to determine priority chemicals, established water quality standards based on technical analyses and comparison with domestic and developed countries’ water quality standards, and conducted an expert review. Water quality standards for protection of aquatic ecosystems will be derived in the near future. This study describes how the water quality standards for protection of human health were developed and implemented. Current status, recent expansion, and future plans for water quality standards in Korea are also covered.
Afficher plus [+] Moins [-]Characteristics of water-soluble inorganic ions in PM2.5 and PM 2.5–10 in the coastal urban agglomeration along the Western Taiwan Strait Region, China Texte intégral
2014
Yin, Liqian | Niu, Zhenchuan | Chen, Xiaoqiu | Chen, Jinsheng | Zhang, Fuwang | Xu, Lingling
PM₂.₅and PM₂.₅–₁₀aerosol samples were collected in four seasons during November 2010, January, April, and August 2011 at 13 urban/suburban sites and one background site in Western Taiwan Straits Region (WTSR), which is the coastal area with rapid urbanization, high population density, and deteriorating air quality. The 10 days average PM₂.₅concentrations were 92.92, 51.96, 74.48, and 89.69 μg/m³in spring, summer, autumn, and winter, respectively, exceeding the Chinese ambient air quality standard for annual average value of PM₂.₅(grade II, 35 μg/m³). Temporal distribution of water-soluble inorganic ions (WSIIs) in PM₂.₅was coincident with PM₂.₅mass concentrations, showing highest in spring, lowest in summer, and middle in autumn and winter. WSIIs took considerable proportion (42.2∼50.1 %) in PM₂.₅and PM₂.₅–₁₀. Generally, urban/suburban sites had obviously suffered severer pollution of fine particles compared with the background site. The WSIIs concentrations and characteristics were closely related to the local anthropogenic activities and natural environment, urban sites in cities with higher urbanization level, or sites with weaker diffuse condition suffered severer WSIIs pollution. Fossil fuel combustion, traffic emissions, crustal/soil dust, municipal constructions, and sea salt and biomass burnings were the major potential sources of WSIIs in PM₂.₅in WTSR according to the result of principal component analysis.
Afficher plus [+] Moins [-]Survival of Escherichia coli O157:H7 in soils under different land use types Texte intégral
2014
Wang, Haizhen | Zhang, Taoxiang | Wei, Gang | Wu, Laosheng | Wu, Jianjun | Xu, Jianming
Laboratory studies on Escherichia coli O157:H7 survival in soils from four different land use types: forest, tea plantation, bamboo grove, and vegetable garden were investigated at 25 ± 1 °C with the field capacity (soil water content at −33 kPa). Results showed that E. coli O157:H7 declined quickly in the test soils, but its survival dynamics varied in the soils under different land use types. The survival time needed to reach the detection limit (td) in the test soils ranged from 2.1 to 3.6 days, with slightly longer tdvalues being observed in soils from the bamboo grove. Stepwise multiple regression analysis revealed that the tdvalues were shorter in sandy, lower pH, and lower organic carbon content soils. Different E. coli O157:H7 survival time in the soils under different land uses suggests that it is important to adapt proper management practices for reducing the potential risks of pathogen contamination when diary manure is applied to agricultural land.
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