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Dust aerosol properties and radiative forcing observed in spring during 2001–2014 over urban Beijing, China
2016
Yu, Xingna | Lu, Rui | Kumar, K Raghavendra | Ma, Jia | Zhang, Qiuju | Jiang, Yilun | Kang, Na | Yang, Suying | Wang, Jing | Li, Mei
The ground-based characteristics (optical and radiative properties) of dust aerosols measured during the springtime between 2001 and 2014 were investigated over urban Beijing, China. The seasonal averaged aerosol optical depth (AOD) during spring of 2001–2014 was about 0.78 at 440 nm. During dust days, higher AOD occurred associated with lower Ångström exponent (AE). The mean AE₄₄₀–₈₇₀ in the springtime was about 1.0, indicating dominance of fine particles over the region. The back-trajectory analysis revealed that the dust was transported from the deserts of Inner Mongolia and Mongolia arid regions to Beijing. The aerosol volume size distribution showed a bimodal distribution pattern, with its highest peak observed in coarse mode for all episodes (especially for dust days with increased volume concentration). The single scattering albedo (SSA) increased with wavelength on dust days, indicating the presence of more scattering particles. Furthermore, the complex parts (real and imaginary) of refractive index showed distinct characteristics with lower imaginary values (also scattering) on dust days. The shortwave (SW; 0.2–4.0 μm) and longwave (LW; 4–100 μm) aerosol radiative forcing (ARF) values were computed from the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model both at the top of atmosphere (TOA) and the bottom of atmosphere (BOA) during dust and non-dust (dust free) days, and the corresponding heating rates and forcing efficiencies were also estimated. The SW (LW) ARF, therefore, produced significant cooling (warming) effects at both the TOA and the BOA over Beijing.
显示更多 [+] 显示较少 [-]Coupling of bio-PRB and enclosed in-well aeration system for remediation of nitrobenzene and aniline in groundwater
2016
A laboratory-scale bio-permeable reactive barrier (bio-PRB) was constructed and combined with enclosed in-well aeration system to treat nitrobenzene (NB) and aniline (AN) in groundwater. Batch-style experiments were first conducted to evaluate the effectiveness of NB and AN degradation, using suspension (free cells) of degrading consortium and immobilized consortium by a mixture of perlite and peat. The NB and AN were completely degraded in <3 days using immobilized consortium, while 3–5 days were required using free cells. The O₂ supply efficiency of an enclosed in-well aeration system was assessed in a box filled with perlite and peat. Dissolved O₂ (DO) concentrations increased to 8–12 mg L⁻¹ in 12 h for sampling ports within 12 cm of the aeration well. A diffusion coefficient as 33.5 cm² s⁻¹ was obtained. The DO concentration was >4 mg L⁻¹ when the aeration system was applied into the bio-PRB system. The NB and AN were effectively removed when the aeration system was functional in the bio-PRB. The removal efficiency decreased when the aeration system malfunctioned for 20 days, thus indicating that DO was an important factor for the degradation of NB and AN. The regain of NB and AN removal after the malfunction indicates the robustness of degradation consortium. No original organics and new formed by-products were observed in the effluent. The results indicate that NB and AN in groundwater can be completely mineralized in a bio-PRB equipped with enclosed in-well aeration system and filled with perlite and peat attached with degrading consortium.
显示更多 [+] 显示较少 [-]Occurrence of cardiovascular drugs in the sewage-impacted Vistula River and in tap water in the Warsaw region (Poland)
2016
Giebułtowicz, Joanna | Stankiewicz, Albert | Wroczyński, Piotr | Nałęcz-Jawecki, Grzegorz
In recent years, cardiovascular diseases were the second most common cause of death worldwide. Therefore, the consumption of drugs used to treat cardiovascular diseases is high. So far, there were no such comprehensive reports regarding the presence of cardiovascular drugs in surface and tap waters, particularly in Central and Eastern Europe. The aim of our study was to determine the presence of 30 pharmaceutically active compounds and some of their metabolites, at specific points of the Vistula River and in tap water samples in the Warsaw region. The analysis was performed using the liquid chromatography–electrospray ionization–tandem mass spectrometry method, coupled to solid-phase extraction. To the best of the authors’ knowledge, this is the first time where the presence of ciprofibrate in the environment was investigated. Cardiovascular drugs found at the highest concentrations (reaching 1 μg/L or higher) in surface water were beta-blockers, sartans and diuretics. In tap water samples, trace amounts of pharmaceuticals were detected, for almost all target compounds. This highlights their inadequate elimination by the treatment facility used in the Warsaw region. The presence of cardiovascular compounds in the aquatic environment could have a long-term effect even at a low exposure level, since synergy effects amongst pharmaceuticals may occur.
显示更多 [+] 显示较少 [-]Exposure to occupational air pollution and cardiac function in workers of the Esfahan Steel Industry, Iran
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.
显示更多 [+] 显示较少 [-]Poly(3-hydroxybutyrate)/metribuzin formulations: characterization, controlled release properties, herbicidal activity, and effect on soil microorganisms
2016
Slow-release formulations of the herbicide metribuzin (MET) embedded in the polymer matrix of degradable poly-3-hydroxybutyrate [P(3HB)] in the form of microparticles, films, microgranules, and pellets were developed and tested. The kinetics of polymer degradation, MET release, and accumulation in soil were studied in laboratory soil microecosystems with higher plants. The study shows that MET release can be controlled by using different techniques of constructing formulations and by varying MET loading. MET accumulation in soil occurs gradually, as the polymer is degraded. The average P(3HB) degradation rates were determined by the geometry of the formulation, reaching 0.17, 0.12, 0.04, and 0.05 mg/day after 60 days for microparticles, films, microgranules, and pellets, respectively. The herbicidal activities of P(3HB)/MET formulations and commercial formulation Sencor Ultra were tested on the Agrostis stolonifera and Setaria macrocheata plants. The parameters used to evaluate the herbicidal activity were plant density and the weight of fresh green biomass measured at days 10, 20, and 30 after sowing. All P(3HB)/MET formulations had pronounced herbicidal activity, which varied depending on MET loading and the stage of the experiment. In the early phases of the experiment, the herbicidal effect of P(3HB)/MET formulations with the lowest MET loading (10 %) was comparable with that of the commercial formulation. The herbicidal effect of P(3HB)/MET formulations with higher MET loadings (25 and 50 %) at later stages of the experiment were stronger than the effect of Sencor Ultra.
显示更多 [+] 显示较少 [-]Terrestrial humic substances in Daliao River and its estuary: optical signatures and photoreactivity to UVA light
2016
Fluorescent dissolved organic matter (FDOM) components were identified by Parallel Factor Analysis (PARAFAC) in surface water of Daliao River and its estuary with a focus on terrestrial humic substance-(HS)-like FDOM identified under two contrasting hydrological conditions. The hydrological conditions did not have noticeable effect on the spectral features of the terrestrial HS-like FDOM, but did affect the components’ intensities and photoreactivity: (1) the intensities of terrestrial HS-like components were higher in the normal flow period than in the high flow period, and (2) a spectrally similar terrestrial HS-like FDOM identified under the two contrasting hydrological conditions showed distinct photoreactivity to the same dose of UVA illumination. The findings indicated that terrestrial HS was generated at lower intensities at the terrestrial sources during the high flow period than during the normal flow period and that the transport of terrestrial HS material through the river-estuary system was affected dominantly by seawater dilution along the salinity gradient while fine-tuned by solar UVA illumination. This study exemplifies the effect of hydrological conditions on optical signatures of terrestrial HS-like FDOM and their photoreactivity towards UVA illumination, improving our understanding of the dynamics of terrestrial HS material in river-estuary systems in the framework of the currently proposed new conceptual model for terrestrial organic matter.
显示更多 [+] 显示较少 [-]Iron and copper catalysis of PCDD/F formation
2016
Liao, Junhong | Buekens, Alfons | Olie, Kees | Yang, Jie | Chen, Tong | Li, Xiaodong
The formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) was explored during de novo tests designed to compare the catalytic activity of copper (II) chloride (CuCl₂) with that of iron (III) oxide (Fe₂O₃) and to test some synergistic effect between these two catalytic compounds. Both copper chloride (CuCl₂) and iron oxide (Fe₂O₃) were earlier proposed as catalysts to explain the PCDD/F emissions from, e.g. municipal solid waste incineration (MSWI). In addition, haematite (Fe₂O₃) is the main iron ore and could be responsible for the typical iron ore sintering plant fingerprint. A total of nine model fly ash (MFA) samples were prepared by mixing and grinding of sodium chloride (NaCl), activated carbon and a powder matrix of silica (SiO₂) with the selected metal compound(s). The conditions of these de novo tests were 1 h in duration, 350 °C in a flow of synthetic combustion gas (10 vol.% oxygen in nitrogen). The effect of Fe–Cu catalyst concentration on yield and distribution pattern of PCDD/F was systematically explored; three strongly differing ratios of [Fe]:[Cu] were considered (1:1, 10:1 and 100:1) to study the potential interactions of Fe₂O₃ and CuCl₂ suggested earlier. The results show some slight rise of PCDD/F formed with raising iron concentration from 0 to 10.1 wt% (no Cu added; 0.1 wt% Cu), as well as strong surging of both amount and average chlorination level of PCDD/F when rising amounts of copper (0 to 1.1 wt%) are introduced. The resulting fingerprints are compared with those from sintering and from MSWI.
显示更多 [+] 显示较少 [-]Coastal hydrogeological system of Mar Piccolo (Taranto, Italy)
2016
The Mar Piccolo basin is an internal sea basin located along the Ionian coast (Southern Italy), and it is surrounded primarily by fractured carbonate karstic environment. Because of the karstic features, the main continental water inflow is from groundwater discharge. The Mar Piccolo basin represents a peculiar and sensitive environment and a social emergency because of sea water and sediment pollution. This pollution appears to be caused by the overlapping effects of dangerous anthropogenic activities, including heavy industries and commercial and navy dockyards. The paper aims to define the contribution of subaerial and submarine coastal springs to the hydrological dynamic equilibrium of this internal sea basin. A general approach was defined, including a hydrogeological basin border assessment to detect inflowing springs, detailed geological and hydrogeological conceptualisation, in situ submarine and subaerial spring measurements, and flow numerical modelling. Multiple sources of data were obtained to define a relevant geodatabase, and it contained information on approximately 2000 wells, located in the study area (1600 km²). The conceptualisation of the hydrogeological basin, which is 978 km² wide, was supported by a 3D geological model that interpolated 716 stratigraphic logs. The variability in hydraulic conductivity was determined using hundreds of pumping tests. Five surveys were performed to acquire hydro-geochemical data and spring flow-yield measurements; the isotope groundwater age was assessed and used for model validation. The mean annual volume exchanged by the hydrogeological basin was assessed equal to 106.93 10⁶ m³. The numerical modelling permitted an assessment of the mean monthly yield of each spring outflow (surveyed or not), travel time, and main path flow.
显示更多 [+] 显示较少 [-]Chemical characteristics of rainwater in Sichuan basin, a case study of Ya’an
2016
Li, Yun-Chun | Zhang, Meng | Shu, Man | Ho, Steven Sai Hang | Liu, Zi-Fang | Wang, Xian-Xiang | Zhao, Xiao-Qing
Rainwater chemistry was investigated at a semi-rural site in Ya’an, Sichuan basin with rain samples collected from May 2013 to July 2014. The rainwater pH values ranged from 3.25 to 6.86, with an annual volume-weighted mean (VWM) of 4.38, and the acid rain frequency was 74 %. Such severe acidification, 15 % of the total events showed a pH below 4.0, attributed to the deficiency of Ca²⁺, significant anthropogenic pollution contribution, and rainy pattern to this area. The annual VWM of total ions concentration was 477.19 μeq/L. NH₄ ⁺ was the most abundant ionic species, followed by SO₄ ²⁻, NO₃ ⁻, Ca²⁺, Cl⁻, Na⁺, K⁺, Mg²⁺, and F⁻ in a descending order. The total ionic concentrations presented a seasonal trend of lower values in autumn and summer but higher ones in winter and spring. Based on enrichment factor, correlation analysis and principle component analysis, three factors were identified: factor 1 (NH₄ ⁺, SO₄ ²⁻, NO₃ ⁻, K⁺, and Cl⁻, 47.45 % of the total variance) related to anthropogenic sources (coal/fuel combustion, biomass burning and agriculture), factor 2 (Ca²⁺, Mg²⁺, Na⁺, and Cl⁻, 34.01 % of the total variance) associated with natural sources, and factor 3 (H⁺, 11.78 % of the total variance) related to free acidity. Back trajectory analysis indicates that the rainwater chemistry in Ya’an was mainly affected by regional air masses from Sichuan basin. Long-range transported air masses from southwest with heavy anthropogenic pollution increased the total ion concentration and acidity of rainwater. Considering its special topography, anthropogenic emissions from regional and long-range transport (especially from southwest) must be controlled effectively to improve the acid rain condition of non-urban areas in Sichuan basin.
显示更多 [+] 显示较少 [-]Laccase encapsulation in chitosan nanoparticles enhances the protein stability against microbial degradation
2016
Koyani, Rina D. | Vazquez-Duhalt, Rafael
A novel concept with the result of enzyme stabilization against microbial degradation in real bioremediation processes was developed through the encapsulation of laccase in chitosan nanoparticles. Besides of abundant information on laccase-chitosan conjugates, we report the laccase encapsulation into nanoparticles based in chitosan. The chitosan-tripolyphosphate technique was applied for the production of morphologically homogeneous enzymatic nanoparticles, with high enzyme encapsulation efficiency, small asymmetric sizes (from 40 to 90 nm), and rough surfaces. Contrary to macroscopic immobilized enzymes, temperature and pH activity profiles of nano-sized laccase were similar to those of free enzyme. The substrate affinity constant (K M) of nano-encapsulated laccase was similar to these from free enzyme, while its activity rate constant (k cₐₜ) represented 60 % of these obtained with free enzyme. Importantly, stability of nano-encapsulated laccase against microbial degradation in soil, compost, and wastewater was significantly increased. After 24 h exposure to wastewater from a treatment plant, the laccase activity of the nanoparticles was 82.8 % of initial activity, compared with only 7.8 % retained activity for free enzyme. After 36 h incubation in compost extract, the laccase nanoparticles showed 72.4 % of the initial activity, while the free enzyme was almost completely inactivated. Finally, after 84 h incubation in soil extract, the nanoparticles and free preparations showed 57.9 and 17.3 % of the initial activity, respectively. Thus, the nanoencapsulation of enzymes able to transform pollutants is an alternative to improve the operational lifetime of enzymes in real environmental applications.
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