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Cu retention in an acid soil amended with perlite winery waste 全文
2016
Rodríguez-Salgado, Isabel | Pérez Rodríguez, Paula | Gómez-Armesto, Antía | Nóvoa-Muñoz, Juan Carlos | Arias-Estévez, Manuel | Fernández-Calviño, David
The effect of perlite waste from a winery on general soil characteristics and Cu adsorption was assessed. The studied soil was amended with different perlite waste concentrations corresponding to 10, 20, 40 and 80 Mg ha⁻¹. General soil characteristics and Cu adsorption and desorption curves were determined after different incubation times (from 1 day to 8 months). The addition of perlite waste to the soil increased the amounts of organic matter as well as soil nutrients such as phosphorus and potassium, and these increments were stable with time. An increase in Cu adsorption capacity was also detected in the perlite waste-amended soils. The effect of perlite waste addition to the soil had special relevance on its Cu adsorption capacity at low coverage concentrations and on the energy of the soil-Cu bonds.
显示更多 [+] 显示较少 [-]Spatiotemporal patterns of surface-suspended particulate matter in the Three Gorges Reservoir 全文
2016
Gao, Mingyang | Zhu, Kongxian | Bi, Yonghong | Hu, Zhengyu
An investigation was conducted in the Three Gorges Reservoir (TGR) seasonally from September 2010 to June 2011 to screen the distribution pattern of suspended particulate matter (SPM). Concentration of SPM, particulate nitrogen (PN), particulate phosphorus (PP), bioavailable particulate phosphorus (BAPP), and chlorophyll a (Chl a) were determined synchronously. Concentration of SPM was higher in the flood season than in the dry season and higher in the mainstream than in the tributaries. Chl a, PN, PP, and BAPP showed similar temporal pattern with SPM distribution. Particulate elements were significantly correlated with concentrations of SPM (p < 0.05). The proportion of algae-derived SPM in total SPM was higher in the tributaries than that in the mainstream. The results revealed that the spatiotemporal heterogeneity determined by hydrodynamics was the characteristic of SPM distribution. The source of SPM was mostly allochthonous. It could be deduced that SPM was an important factor affecting the water quality and algal growth in TGR by releasing or absorbing particulate nutrient.
显示更多 [+] 显示较少 [-]Synergetic effects of Sr-doped CuBi2O4 catalyst with enhanced photoactivity under UVA– light irradiation 全文
2016
Elaziouti, A. | Laouedj, N. | Bekka, A.
Sr-doped CuBi₂O₄ micro-particles were successively synthesized via a solid-state technique and were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and UV–vis diffuse reflectance spectroscopy (UV–vis-DRS) techniques. Results show that Sr-doped CuBi₂O₄ was crystallized with a spinel-type structure and tetragonal crystal system, and the band gap energy was about 1.35 eV. The as-prepared Sr-doped CuBi₂O₄ treated at 573 °C for 12 h exhibited the highest efficiency, as a result of 97.22 % of CR degradation within 220 min, which is approximately 31 times greater than CR photodegradation when catalyzed by CuBi₂O₄ (3.13 %) and about 2.3 times superior than that catalyzed by the untreated Sr–doped CuBi₂O₄ sample (42.08 %). Pseudo-first-order kinetic model gave the best fit, with highest correlation coefficients (R ² = 0.94–0.97). The Sr–doping and extending reaction time up to 12 h could be effective in producing Sr-doped CuBi₂O₄ materials that delay electron–hole recombination, thereby increasing the lifetime of the electron electron–hole separation and support the charge carrier transfer to the catalyst surface. On the basis of the calculated energy band positions, superoxide radical anions (O₂ •–) were the main oxidative species responsible for the photocatalytic degradation of CR dye solution.
显示更多 [+] 显示较少 [-]Application of a novel electrochemical sensor containing organo-modified sericite for the detection of low-level arsenic 全文
2016
Kim, Mu-Nui | Yang, Jae-Kyu | Park, Youn-Jong | Yi, Ir-yŏng | Min, Kyung-Chul | Jeon, Choong | Lee, Seung-Mok
A simple cyclic voltammetry (CV) analytical method with organo-modified sericite for the working electrode was investigated to detect As(III) in an aquatic environment, and optimal conditions for the reliable measurement of trace amounts of As(III) were studied. A distinct, specific peak was clearly observed at 0.8 V due to the reduction of H₃AsO₄ to H₃AsO₃. The specific peak current of arsenic increased with increasing the concentration of As(III) and initially increased proportionally to the scan rates. However, it disappeared as the scan rate increased over 400 mV/s. Because the surface of the organo-modified sericite electrode rapidly became saturated with As(III) when the deposition time increased, an optimal deposition time was determined as 60 s. Pb²⁺ had no significant influence on the peak signal of As(III), whereas it was reduced as the ratio of Cu/As increased. Considering the detection limit of arsenic (1 ppb), this system can be used to detect low levels of As(III) in water systems.
显示更多 [+] 显示较少 [-]Carbonaceous aerosols over China—review of observations, emissions, and climate forcing 全文
2016
Wang, Linpeng | Zhou, Xuehua | Ma, Yujie | Cao, Zhaoyu | Wu, Ruidong | Wang, Wenxing
Carbonaceous aerosols have been attracting attention due to the influence on visibility, air quality, and regional climate. Statistical analyses based on concentration levels, spatial-temporal variations, correlations, and organic carbon (OC) to element carbon (EC) ratios from published data of OC and EC in particulate matter (PM₂.₅ and PM₁₀) were carried out in order to give a carbonaceous aerosol profile in China. The results showed maxima for OC of 29.5 ± 18.2 μg C m⁻³ and for EC of 8.4 ± 6.3 μg C m⁻³ in winter and minima for OC of 12.9 ± 7.7 μg C m⁻³ in summer and for EC of 4.6 ± 2.8 μg C m⁻³ in spring. In addition, OC and EC both had higher concentrations in urban than those in rural sites. Carbonaceous aerosol levels in China are about three to seven times higher compared to those in the USA and Europe. OC and EC occupied 20 ± 6 and 7 ± 3 % of PM₂.₅ mass and 17 ± 7 and 5 ± 3 % of PM₁₀ mass, respectively, implying that carbonaceous aerosols are the main component of PM, especially OC. Secondary organic carbon (SOC) was a significant portion of PM and contributed 41 ± 26 % to OC and 8 ± 6 % to PM₂.₅ mass. The OC/EC ratio was 3.63 ± 1.73, which, along with the good correlation between OC and EC and the OC to EC slope of 2.29, signifies that coal combustion and/or vehicular exhaust is the dominated carbonaceous aerosol source in China. These provide a primary observation-based understanding of carbonaceous aerosol pollution in China and have a great significance in improving the emission inventory and climate forcing evaluation.
显示更多 [+] 显示较少 [-]Spontaneous revegetation vs. forestry reclamation in post-mining sand pits 全文
2016
Šebelíková, Lenka | Řehounková, Klára | Prach, Karel
Vegetation development of sites restored by two different methods, spontaneous revegetation and forestry reclamation, was compared in four sand pit mining complexes located in the southern part of the Czech Republic, central Europe. The space-for-time substitution method was applied to collect vegetation records in 13 differently aged and sufficiently large sites with known history. The restoration method, age (time since site abandonment/reclamation), groundwater table, slope, and aspect in all sampled plots were recorded in addition to the visual estimation of percentage cover of all present vascular plant species. Multivariate methods and GLM were used for the data elaboration. Restoration method was the major factor influencing species pattern. Both spontaneously revegetated and forestry reclaimed sites developed towards forest on a comparable timescale. Although the sites did not significantly differ in species richness (160 species in spontaneously revegetated vs. 111 in forestry reclaimed sites), spontaneously revegetated sites tended to be more diverse with more species of conservation potential (10 Red List species in spontaneous sites vs. 4 Red List species in forestry reclaimed sites). These results support the use of spontaneous revegetation as an effective and low-cost method of sand pit restoration and may contribute to implementation of this method in practice.
显示更多 [+] 显示较少 [-]Mobility of heavy metals from polluted sediments of a semi-enclosed basin: in situ benthic chamber experiments in Taranto’s Mar Piccolo (Ionian Sea, Southern Italy) 全文
2016
Emili, Andrea | Acquavita, Alessandro | Covelli, Stefano | Spada, Lucia | Di Leo, Antonella | Giandomenico, Santina | Cardellicchio, Nicola
In situ benthic flux experiments were conducted at two stations in the Mar Piccolo of Taranto (Italy), one of the most industrialised and contaminated coastal areas of the Mediterranean. Sediments of the two stations are notably different in their trace metal content, with a station closer to a Navy harbour showing higher mean concentrations of almost all investigated metals (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn). Conversely, both stations are characterised by significant Hg contamination, compared to the local baseline. Results of a sequential extraction scheme on surface sediments suggest a relatively scarce mobility of the examined metals (Zn > Ni > Cr > As > Cu > Pb). A Hg-specific extraction procedure showed that most of the element (93.1 %) occurs in a fraction comprising Hg bound to Fe/Mn oxi-hydroxides. Reduction of these oxides may affect Hg remobilisation and redistribution. Porewater profiles of dissolved trace metals were quite similar in the two sites, although significant differences could be observed for Al, Cu, Fe and Hg. The highest diffusive fluxes were observed for As, Fe and Mn. Mobility rates of several trace elements (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn) were directly measured at the sediment–water interface. Results from benthic in situ incubation experiments showed increasing dissolved metal concentrations with time, resulting in higher fluxes for Cu, Fe, Hg, V and Zn in the most contaminated site. Conversely, fluxes of Mn, Ni and Pb were comparable between the two stations. The estimated flux of Hg (97 μg m⁻² day⁻¹) was the highest observed among similar experiments conducted in other highly contaminated Mediterranean coastal environments. Benthic fluxes could be partially explained by considering rates of organic matter remineralisation, dissolution of Fe/Mn oxy-hydroxides and metal speciation in sediments. Seasonal and spatial variation of biogeochemical parameters can influence metal remobilisation in the Mar Piccolo area. In particular, metals could be promptly remobilised as a consequence of oxygen depletion, posing a serious concern for the widespread fishing and mussel farming activities in the area.
显示更多 [+] 显示较少 [-]Metals and PCB levels in some edible marine organisms from the Ionian Sea: dietary intake evaluation and risk for consumers 全文
2016
Giandomenico, Santina | Cardellicchio, Nicola | Spada, Lucia | Annicchiarico, Cristina | Di Leo, Antonella
Concentrations of some metals (Cd, Cu, As, Hg, Pb) and polychlorinated biphenyls (PCBs) were investigated in edible marine organisms from different trophic levels and feeding behaviour like bivalve molluscs (Mytilus galloprovincialis and Chlamys glabra), gastropod molluscs (Hexaplex trunculus) and some commercial species of fish (Trachurus trachurus, Boops boops, Sarpa salpa and Gobius niger). These species were collected in the first inlet of the Mar Piccolo of Taranto (Ionian Sea, Southern Italy), classified as ‘Site of National Interest’ established by National Law 426 (1998) and included in the ‘National Environmental Remediation and Restoration Projects’. The aim of this work was to investigate contamination levels and public health risks, associated with consuming seafood harvested from these areas. Moreover, in this study, was also estimated the weekly intake in children and adults, both for metals and PCBs. In comparison with the permissible limits set by EC Regulations, Cd and Pb levels were over the limit in the H. trunculus (in all sampling stations) and in the fish T. trachurus respectively. PCBs were over the legal limit in all sampled species with the exception of M. galloprovincialis (station 1), C. glabra and the herbivorous fish S. salpa. In the fish T. trachurus, for example, the concentration of six target PCBs was about five times higher than the EC limit. The estimated intakes of those trace elements included in this study through seafood consumption by the population exceed the provisional tolerable weekly intake recommended by the Joint FAO/WHO Expert Committee on Food Additives for Cd and Hg in the H. trunculus and T. trachurus, especially in children. Moreover, hazard quotience (HQ) for Hg and Cd was >1 in the children for T. trachurus and H. trunculus consumption. As regard non-dioxin-like PCB (NDL-PCB), the estimated intake were always above the ‘provisional guidance value’ (70 ng/kg body weight) Arnich et al. (Regul Toxicol Pharm 54: 287–2, 2009) for all sampled organism. Thus, health risks due to the dietary Hg, Cd and PCBs intake, especially for children, cannot be excluded. Therefore, an extended remediation programme is necessary to safeguard marine ecosystem, human health and, not less important, the economic activities, in the Taranto marine area.
显示更多 [+] 显示较少 [-]Effect of single and combination of three triazine metabolites at environmental concentrations on early life stages of common carp (Cyprinus carpio L.) 全文
2016
Velisek, Josef | Stara, Alzbeta | Zuskova, Eliska
The sensitivity of early life stages of common carp (Cyprinus carpio L.) to chronic exposure to single and combined environmental concentrations of the triazine metabolites terbuthylazine 2-hydroxy, terbuthylazine-desethyl and atrazine 2-hydroxy was evaluated under laboratory conditions. Their effects were assessed on lipid peroxidation, antioxidant enzymes (total superoxide dismutase, glutathione reductase, catalase, glutathione S-transferase, reduced glutathione), mortality, growth, development and histology. Single metabolites (terbuthylazine 2-hydroxy—0.73 μg/L; terbuthylazine-desethyl—1.80 μg/L; atrazine 2-hydroxy—0.66 μg/L) and combinations were not associated with negative effects on hatching, behaviour, embryo viability, growth or early ontogeny. Carp exposed to terbuthylazine-desethyl at 1.80 μg/L showed significantly lower total superoxide dismutase and glutathione reductase activity compared with the control group. Liver histology revealed diffused steatosis associated with the presence of lipid inclusions in hepatic cells in groups exposed to terbuthylazine-desethyl, atrazine 2-hydroxy and the tested combination of metabolites.
显示更多 [+] 显示较少 [-]Degradation of typical antibiotics during human feces aerobic composting under different temperatures 全文
2016
Shi, Honglei | Wang, Xiaochang C. | Li, Qian | Jiang, Qishao
Four typical antibiotics were added to human feces for aerobic composting using batch reactors with sawdust as the bulk matrix. Under three composting temperatures (room temperature, 35 ± 2 °C and 55 ± 2 °C), decreases in the extractable concentrations of antibiotics in the compost were monitored for 20 days. As a result, the removals of extractable tetracycline and chlortetracycline were found to be more temperature-dependent than the removals of sulfadiazine and ciprofloxacin. However, more than 90 % of all of the extractable antibiotics were removed at 55 ± 2 °C. Three specific experiments were further conducted to identify the possible actions for antibiotic removal, including self-degradation in aqueous solution, composting with a moist sterile sawdust matrix without adding feces and composting with human feces and moist sterile sawdust. As a result, it was found that the removal of tetracycline and chlortetracycline was mainly due to chemical degradation in water, whereas the removal of sulfadiazine was mainly attributed to adsorption onto sawdust particles. The microbial activity of compost varied with temperature to a certain extent, but the differences were insignificant among different antibiotics. Although microbial action is important for organic matter decomposition, its contribution to antibiotic degradation was small for the investigated antibiotics, except for ciprofloxacin, which was degraded by up to 20 % due to microbial action.
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