Gas/Substrate Fluxes and Microbial Community in Phenol Biodegradation Using an O2‐Based Membrane Biofilm Reactor          下载免费PDF全文

Özge Hanay  Ergin Taşkan  Burçin Yıldız  Halil Hasar  Eoin Casey 《洁净——土壤、空气、水》2014,42(1):36-42

  相似文献   

Simultaneous Bromate and Nitrate Reduction in Water Using Sulfur‐Utilizing Autotrophic and Mixotrophic Denitrification Processes in a Fixed Bed Column Reactor          下载免费PDF全文

Sevgi Demirel  İbrahim Uyanık  Adem Yurtsever  Hakan Çelikten  Deniz Uçar 《洁净——土壤、空气、水》2014,42(9):1185-1189

  相似文献   

Comments on Rebuttal of M. Sagir     

Mufide Banar  Barbaros Murat Kose  Aysun Ozkan  Ilgın Poyraz Acar 《Environmental Geology》2009,58(5):1143-1144

This rebuttal was written in response to the rebuttal of the paper “choosing a municipal landfill site by analytic network process” published in 2007 by M. Sagir. This study was conducted as an application for the landfill site selection in the environmental engineering discipline. Since ANP was only the “instrument” used in our study, the details of this existing methodology were referenced, and not presented, due to page limitations and to match the content of the journal. Responses to M. Sagir’s comments are discussed within the body of this rebuttal.  相似文献   

Geochemistry and mineralogy of shallow alluvial aquifers in Daudkandi upazila in the Meghna flood plain, Bangladesh   总被引：1，自引：0，他引：1  

M. Aziz Hasan  Mattias von Br?mssen  Prosun Bhattacharya  Kazi Matin Ahmed  Arif Mohiuddin Sikder  Gunnar Jacks  Ondra Sracek 《Environmental Geology》2009,57(3):499-511

The shallow alluvial aquifers of the delta plains and flood plains of Bangladesh, comprises about 70% of total land area are mostly affected by elevated concentrations of arsenic (As) in groundwater exposing a population of more than 35 million to As toxicity. Geochemical studies of shallow alluvial aquifer in the Meghna flood plain show that the uppermost yellowish grey sediment is low in As (1.03 mg/kg) compared to the lower dark grey to black sediment (5.24 mg/kg) rich in mica and organic matter. Sequential extraction data show that solid phase As bound to poorly crystalline and amorphous metal (Fe, Mn, Al)-oxyhydroxides is dominant in the grey to dark grey sediment and reaches its maximum level (3.05 mg/kg) in the mica rich layers. Amount of As bound to sulphides and organic matter also peaks in the dark grey to black sediment. Vertical distributions of major elements determined by X-ray fluorescence (XRF) show that iron (Fe₂O₃), aluminum (Al₂O₃) and manganese (MnO) follow the general trend of distribution of As in the sediments. Concentrations of As, Mn, Fe, HCO₃ ⁻, SO₄ ²⁻ and NO₃ ⁻ in groundwater reflect the redox status of the aquifer and are consistent with solid phase geochemistry. Mineralogical analysis by X-ray diffraction (XRD) and scanning electron microscopy (SEM) fitted with energy dispersive X-ray spectrometer (EDS) revealed dominance of crystalline iron oxides and hydroxides like magnetite, hematite and goethite in the oxidised yellowish grey sediment. Amorphous Fe-oxyhydroxides identified as grain coating in the mica and organic matter rich sediment suggests weathering of biotite is playing a critical role as the source of Fe(III)-oxyhydroxides which in turn act as sink for As. Presence of authigenic pyrite in the dark grey sediment indicates active reduction in the aquifer.  相似文献   

Influence of Seawater on the Suction and Swelling Behavior of Clayey Soils     

Hasan Firat Pulat 《Marine Georesources & Geotechnology》2013,31(5):466-472

The present study examines the suction characteristics and swelling behavior of clayey soils when exposed to natural seawater with respect to distilled water. The effects of saline waters on the engineering behavior of soils need to be determined since the salinity of the pore fluid of soils near coastal areas increases continuously. Six clayey soil samples with different mineralogy and characteristics were gathered and tested to determine the suction and swelling characteristics in the presence of natural seawater and distilled water. The results show that the total suction values of the samples are higher in the presence of seawater than in distilled water. The samples with high swelling potential have lower matric suction values than nonswelling soils. Moreover, in contrast to swelling-type soils, the matric suction values of the nonswelling soils remain similar in the presence both distilled water and seawater. The modified free swell index (MFSI) of the samples is well correlated with the liquid limit (LL), plasticity index (PI), and cation exchange capacity (CEC) in distilled water. However, coefficients of determination decreased in the presence of seawater. Also, there is no significant correlation existing between total and matric suction values and the MFSI values of the samples.  相似文献   

Toxic metal (Pb, Cd and Hg) levels in the nearshore surface sediments from the European and Anotolian Shores of Bosphorus, Turkey     

Balkıs N  Aktan Y  Balkıs N 《Marine pollution bulletin》2012,64(9):1938-1939

In this study, some toxic metal such as Pb, Cd and Hg analyzes have been done in the nearshore surface sediments. Sediment samples have been collected from five parts from the European and Anotolian Shores of the Bosphorus during 2003-2004. Total Pb, Cd and Hg contents vary between <0.01μgg(-1) and 238μgg(-1); <0.01μgg(-1) and 0.92μgg(-1); 0.001μgg(-1) and 0.45μgg(-1), respectively. Contamination Factor (CF) values of Pb and Cd range between 1 and 3 whilst CF values of Hg are lower than 1 in all the stations. It means that there are no Hg metal enrichment by natural or anthropogenic inputs contrary to moderately contamination for Pb and Cd metals throughout the Bosphorus sediments.  相似文献   

The Effects of the Earth’s Curvature on Gravity and Geoid Calculations   总被引：1，自引：0，他引：1  

Hasan??av?akEmail author 《Pure and Applied Geophysics》2012,169(4):733-740

While it is obvious that large-scale gravity studies should account for the sphericity of the Earth, each case should be examined. If a geometry model is very large for the 3D-gravity calculation, it cannot be correctly defined in Cartesian coordinates. Because of the Earth’s curvature it is necessary to use spherical coordinates, the importance of which is shown in this paper. The calculation of the gravity for a cylinder reveals, 1 m above the center of the cylinder, a relative difference of 13% between the models with Cartesian and spherical coordinates.  相似文献   

Sea level variability at Antalya and Mente? tide gauges in Turkey: atmospheric, steric and land motion contributions     

Mehmet Simav  Hasan Yildiz  Ali Türkezer  Onur Lenk  Emin ?zsoy 《Studia Geophysica et Geodaetica》2012,56(1):215-230

Sea level trends and interannual variability at Antalya and Menteş tide gauges are investigated during the 1985–2001 period, quantifying the roles of atmospheric, steric and local land motion contributions. Tide gauge sea level measurements, temperature/salinity climatologies and GPS data are used in the analyses and the results are compared with the output of a barotropic model forced by atmospheric pressure and wind. The overall sea level trends at two tide gauges collocated with GPS are in the range of 5.5 to 7.9 mm/yr during the study period, but showing different behaviour in the sub-periods 1985–1993 and 1993–2001 due to variations in the contributing factors both in space and time. After the removal of the atmospheric forcing and steric contribution from sea level records, the resulting trends vary between 1.9 to 4.5 mm/yr in Antalya and −1.2 to −11.6 mm/yr in Menteş depending on the period considered. Vertical land movement estimated from GPS data seems to explain the high positive residual trend in Antalya during the whole period. On the other hand, the source of the highly negative sea level trend of about −14 mm/yr in Menteş during 1985–1993 could not be resolved with the available datasets. Interannual variability of wind and atmospheric pressure appear to dominate the sea level at both tide gauges during the study period. Atmospheric and steric contributions together account for ∼50% of the total sea level variance at interannual time scales. Mass induced sea level variations which were not considered in this study may help to close the sea level trend budgets as well as to better explain the interannual sea level variance.  相似文献   

A study of regional gravity field recovery from GOCE vertical gravity gradient data in the Auvergne test area using collocation     

Hasan Yildiz 《Studia Geophysica et Geodaetica》2012,56(1):171-184

Gravity field and steady-state Ocean Circulation Explorer (GOCE) is the first satellite mission that observes gravity gradients from the space, to be primarily used for the determination of high precision global gravity field models. However, the GOCE gradients, having a dense data distribution, may potentially provide better predictions of the regional gravity field than those obtained using a spherical harmonic Earth Geopotential Model (EGM). This is investigated in Auvergne test area using Least Squares Collocation (LSC) with GOCE vertical gravity gradient anomalies (T_zz), removing the long wavelength part from EGM2008 and the short wavelength part by residual terrain modelling (RTM). The results show that terrain effects on the vertical gravity gradient are significant at satellite altitude, reaching a level of 0.11 E?tv?s unit (E.U.) in the mountainous areas. Removing the RTM effects from GOCE T_zz leads to significant improvements on the LSC predictions of surface gravity anomalies and quasigeoid heights. Comparison with ground truth data shows that using LSC surface free air gravity anomalies and quasi-geoid heights are recovered from GOCE T_zz with standard deviations of 11 mGal and 18 cm, which is better than those obtained by using GOCE EGMs, demonstrating that information beyond the maximal degree of the GOCE EGMs is present. Investigation of using covariance functions created separately from GOCE T_zz and terrestrial free air gravity anomalies, suggests that both covariance functions give almost identical predictions. However, using covariance function obtained from GOCE T_zz has the effect that the predicted formal average error estimates are considerably larger than the standard deviations of predicted minus observed gravity anomalies. Therefore, GOCE T_zz should be used with caution to determine the covariance functions in areas where surface gravity anomalies are not available, if error estimates are needed.  相似文献   

Speciation and Determination of Inorganic Mercury and Methylmercury by Headspace Single Drop Microextraction and Electrothermal Atomic Absorption Spectrometry in Water and Fish     

Deniz Yurtsever Sarıca  Ali Rehber Türker 《洁净——土壤、空气、水》2012,40(5):523-530

In this study, headspace single drop microextraction (HS‐SDME) method in combination with electrothermal atomic absorption spectrometry (ETAAS) method was developed and validated for the speciation and determination of inorganic mercury (iHg) and methylmercury (MeHg). MeHg and iHg species were reduced to volatile methylmercury hydride (CH₃HgH) and elemental mercury, respectively, in the presence of NaBH₄ and trapped onto a drop of acceptor phase in the tip of a microsyringe. Thiourea and ammonium pyrrolydinedithiocarbamate (APDC) were tested as the acceptor phase. The experimental parameters of the method such as microextraction time, temperature, NaBH₄ concentration, acceptor phase concentration, and pH of the medium were investigated to obtain distinctive conditions for mercury species. Possible interference effects have also been investigated. In order to validation of the method, analytical figures of merits such as accuracy, precision, limit of detection (LOD), limit of quantitation (LOQ), and linear working range have been evaluated. Accuracy of the method has been verified by analyzing certified reference materials (BCR 453 Tuna fish) and spiked samples. The proposed method was applied for the speciation and determination of mercury species in water and fish samples. Mercury species (MeHg and iHg) have been determined in the real samples with a relative error less than 10%.  相似文献