Flood risk perception and its determinants among rural households in two communities in Khyber Pakhtunkhwa,Pakistan     

Ullah  Farman  Saqib  Shahab E.  Ahmad  Mokbul Morshed  Fadlallah  Mahmoud Ali 《Natural Hazards》2020,104(1):225-247

Natural Hazards - Risk perception plays a vital part in flood risk management and mitigation strategies. Therefore, this study aims at first to measure the risk perception of the vulnerable...  相似文献   

Vortex Assisted Liquid–Liquid Microextraction Using Triton X‐114 for Ultratrace Cadmium Prior to Analysis          下载免费PDF全文

Sumaira Khan  Erkan Yilmaz  Tasneem Gul Kazi  Mustafa Soylak 《洁净——土壤、空气、水》2014,42(8):1083-1088

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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   

Temperature Sensitivity and Soil Organic Carbon Pools Decomposition under Different Moisture Regimes: Effect on Total Microbial and Enzymatic Activity          下载免费PDF全文

Waseem Hassan  Rizwana Bano  Bashir Ullah Khatak  Imtiaz Hussain  Mohummad Yousaf  Julie David 《洁净——土壤、空气、水》2015,43(3):391-398

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Diffusive equilibrium in thin films provides evidence of suppression of hyporheic exchange and large‐scale nitrate transformation in a groundwater‐fed river          下载免费PDF全文

P. Byrne  H. Zhang  S. Ullah  A. Binley  A.L. Heathwaite  C.M. Heppell  K. Lansdown  M. Trimmer 《水文研究》2015,29(6):1385-1396

The hyporheic zone of riverbed sediments has the potential to attenuate nitrate from upwelling, polluted groundwater. However, the coarse‐scale (5–10 cm) measurement of nitrogen biogeochemistry in the hyporheic zone can often mask fine‐scale (<1 cm) biogeochemical patterns, especially in near‐surface sediments, leading to incomplete or inaccurate representation of the capacity of the hyporheic zone to transform upwelling NO₃^?. In this study, we utilised diffusive equilibrium in thin‐films samplers to capture high resolution (cm‐scale) vertical concentration profiles of NO₃^?, SO₄^2?, Fe and Mn in the upper 15 cm of armoured and permeable riverbed sediments. The goal was to test whether nitrate attenuation was occurring in a sub‐reach characterised by strong vertical (upwelling) water fluxes. The vertical concentration profiles obtained from diffusive equilibrium in thin‐films samplers indicate considerable cm‐scale variability in NO₃^? (4.4 ± 2.9 mg N/L), SO₄^2? (9.9 ± 3.1 mg/l) and dissolved Fe (1.6 ± 2.1 mg/l) and Mn (0.2 ± 0.2 mg/l). However, the overall trend suggests the absence of substantial net chemical transformations and surface‐subsurface water mixing in the shallow sediments of our sub‐reach under baseflow conditions. The significance of this is that upwelling NO₃^?‐rich groundwater does not appear to be attenuated in the riverbed sediments at <15 cm depth as might occur where hyporheic exchange flows deliver organic matter to the sediments for metabolic processes. It would appear that the chemical patterns observed in the shallow sediments of our sub‐reach are not controlled exclusively by redox processes and/or hyporheic exchange flows. Deeper‐seated groundwater fluxes and hydro‐stratigraphy may be additional important drivers of chemical patterns in the shallow sediments of our study sub‐reach. © 2015 The Authors. Hydrological Processes Published by John Wiley & Sons Ltd.  相似文献   

Evaluation of Bioavailability and Partitioning of Aluminum in Sediment Samples of Different Ecosystems by Modified Sequential Extraction Methods     

Sumaira Khan  Tasneem G. Kazi  Muhammad B. Arain  Nida F. Kolachi  Jameel A. Baig  Hassan I. Afridi  Abdul Q. Shah 《洁净——土壤、空气、水》2013,41(8):808-815

Sequential extraction procedures are widely used to characterize the different operational fractions with different potential toxicity of metals in environmental solid samples. The present work describes the application of different analytical approaches for sequential extraction of aluminum to evaluate its mobility, availability, and persistent chemical forms in sediment samples of different fresh water ecosystems (lake, canal, and river). The conventional BCR three‐stage sequential extraction procedure (C‐BCR) was modified at each stage, by applying ultrasonic device (U‐BCR), in order to shorten the required shaking time of 16 h for each three steps (excluding the hydrogen peroxide digestion in step 3, which was not performed with ultrasonic bath), could be completed in 40, 50, and 45 min, respectively. The aluminum in all extracts were determination by atomic absorption spectrometry using nitrous oxide – acetylene flame. The accuracy of results obtained from C‐BCR and proposed U‐BCR was verified with literature reported values of certified sediment sample (BCR 701). The overall recoveries of aluminum obtained by proposed U‐BCR were found in the range of 96.7–113% of those values obtained with C‐BCR for all fractions. Use of ultrasonic device, provided a large saving in extraction time relative to conventional shaking. It was observed that major part of Al in real sediment samples (80–83% of total Al) were bound to residual fraction. The acid soluble fraction of aluminum extracted by 0.11 mol/L CH₃COOH has good correlation with aluminum content in corresponding water samples of each ecosystem.  相似文献   

A comprehensive study on the surface chemistry of particulate matter collected from Jeddah,Saudi Arabia     

Asim Jilani  Syed Zajif Hussain  Mohd Hafiz Dzarfan Othman  Usama Zulfiqar  Muhammad Bilal Shakoor  Imran Ullah Khan  Javed Iqbal  Attieh A. Al-Ghamdi  Ahmed Alshahrie 《Journal of Atmospheric Chemistry》2018,75(3):271-283

In this work, the X-ray Photoelectron Spectroscopy (XPS) technique is utilized to analyze the surface chemical composition of particulate matter (PM) which was collected from various locations at Jeddah, Saudi Arabia. The main elements found on the surface of PM are carbon (C), oxygen (O) and silicon (Si) with combined percentage of 89.4–94.9 while traces of nitrogen (N), calcium (Ca), aluminum (Al), sodium (Na), chlorine (Cl), manganese (Mg), and sulfur (S) were also present. The analyzed XPS chemical state of C, O and Si was further used to determine their bonding with other elements occurring over the surface of PM. Carbon was found in the form of carbides (18.86%), fluorides (2.39%) and carbonates (78.75%); oxygen was observed as oxides (21.05%) and hydroxides (73.42%) of other metals; and silicon was detected as silicones (12.16%), nitrides (82.53%) and silicates (5.25%). The particle size of a PM is also of great concern for health issues, and thus has been investigated by the Field Emission Scanning Electron Microscope (FESEM). The Energy Dispersive X-ray Spectroscopy (EDS) was employed for cross verification of detected elements by XPS.  相似文献   

Hydrological and geochemical constraints on the mechanism of formation of arsenic contaminated groundwater in Sonargaon,Bangladesh     

Takaaki Itai  Harue Masuda  Ashraf A. Seddique  Muneki Mitamura  Teruyuki Maruoka  Xiaodong Li  Minoru Kusakabe  Biswas K. Dipak  Abida Farooqi  Toshiro Yamanaka  Shinji Nakaya  Jun-ichi Matsuda  Kazi Matin Ahmed 《Applied Geochemistry》2008

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Cotton production under risk: a simultaneous adoption of risk coping tools     

Farhad Zulfiqar  Raza Ullah  Muhammad Abid  Abid Hussain 《Natural Hazards》2016,84(2):959-974

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Rock Physics Modeling and Reservoir Characterization to Estimate Hydrocarbon Zone of Cretaceous and Paleocene Strata and Subsurface Stratigraphic Correlation of Sulaiman Fold Belt to Sulaiman Depression     

Rehman  Saif ur  Umar  Muhammad  Ehsan  Muhammad Irfan  Munawar  Muhammad Jawad  Miraj  Muhammad Armaghan Faisal  Ullah  Muhammad Fahad 《Doklady Earth Sciences》2023,507(3):S446-S456

Doklady Earth Sciences - The research work involves rock physics modeling and reservoir characterization of Suliman fold belt to sulamain fold depression. This area is a brighter zone for...  相似文献