A laboratory batch study on arsenic sorption and desorption on guava orchard soils of Baruipur,West Bengal,India   总被引：1，自引：0，他引：1  

Sudip Jyoti Sahu  Bibhash Nath  Sharmi Roy  Biswapati Mandal  Debashis Chatterjee 《Journal of Geochemical Exploration》2011

Groundwater contaminated with arsenic (As), when extensively used for irrigation, causes potentially long term detrimental effects to surface soils. Such contamination can also directly affect human health when irrigated crops, such as rice, vegetable and fruits, are used for human consumption. Therefore, an understanding of the sorption and desorption behavior of As in surface soils is of high importance, because these processes regulate the bioavailability of As in the soil environment. In this study, we have collected soils from guava orchards of Baruipur, West Bengal, and characterized soil chemistry and batch sorption and desorption behavior in the laboratory. The sorption and desorption behavior of As in the soils were examined using the Langmuir and Freundlich sorption equation. Regression analysis of the soil chemical characteristics and sorption equation parameters were also performed. The results suggest that the sorption behavior of arsenate is highly dependent on soil characteristics, specifically organic carbon, clay and Al₂O₃ content of the soils. Whereas desorption behavior is critically influenced by the presence of high concentrations of amorphous and/or crystalline Fe₂O₃ in the soils. Retention of the significant portion of As in the soils (~ 84% of the total) suggests that As in the orchard soils may not be highly bioavailable to plants for uptake. However, more detailed studies will be required to ascertain the role of individual soil components on the As sorption and desorption processes.  相似文献   

Solitonic, quasi-periodic and periodic pattern of electron acoustic waves in quantum plasma     

Biswajit Sahu  Swarup Poria  Rajkumar Roychoudhury 《Astrophysics and Space Science》2012,341(2):567-572

In the present paper we investigate the nonlinear wave structures of electron acoustic waves (EAWs) in an unmagnetized quantum plasma consisting of cold and hot electrons and ions. The one-dimensional quantum hydrodynamic model is used to study the quantum correction of the well known EAWs. Computational investigations have been performed to examine the effects of quantum diffraction and Mach number on nonlinear waves. It is shown that for Mach number M<1, soliton solution exist and for M>1, quasi-periodic and periodic type solution exist. The effects of other several parameters on the properties of EAWs are also discussed.  相似文献   

Small amplitude double-layers in an electron depleted dusty plasma with ions featuring the Tsallis distribution     

Biswajit Sahu  Mouloud Tribeche 《Astrophysics and Space Science》2012,341(2):573-578

The properties of dust acoustic double-layers (DA-DLs) in an unmagnetized electron depleted dusty plasma consisting of inertial dust fluid and ions featuring Tsallis statistics are investigated. It is found that our plasma model can admit compressive as well as rarefactive DA-DLs depending on the value of nonextensive parameter q. As the value of q increases, the negative DA-DL shrinks and, beyond a certain critical value, develops into a positive structure allowing therefore the existence of compressive DA-DLs.  相似文献   

Tight Reassembly of Gondwana Exposes Phanerozoic Shears in Africa as Global Tectonic Players     

C.V. Reeves  M.J. de Wit  B.K. Sahu 《Gondwana Research》2004,7(1):7-19

Aeromagnetic surveys help reveal the geometry of Precambrian terranes through extending the mapping of structures and lithologies from well-exposed areas into areas of younger cover. Continent-wide aeromagnetic compilations therefore help extend geological mapping beyond the scale of a single country and, in turn, help link regional geology with processes of global tectonics. In Africa, India and related smaller fragments of Gondwana, the margins of Precambrian crustal blocks that have escaped (or successfully resisted) fracture or extension in Phanerozoic time can often be identified from their aeromagnetic expression. We differentiate between these rigid pieces of Precambrian crust and the intervening lithosphere that has been subjected to deformation (usually a combination of extension and strike-slip) in one or more of three rifting episodes affecting Africa during the Phanerozoic: Karoo, Early Cretaceous and (post-) Miocene. Modest relative movements between adjacent fragments in the African mosaic, commensurate with the observed rifting and transcurrent faulting, lead to small adjustments in the position of sub-Saharan Africa with respect to North Africa and Arabia. The tight reassembly of Precambrian sub-Saharan Africa with Madagascar, India, Sri Lanka and Antarctica (see animation in http://kartoweb.itc.nl/gondwana) can then be extended north between NW India and Somalia once the Early Cretaceous movements in North Africa have been undone. The Seychelles and smaller continental fragments that stayed with India may be accommodated north of Madagascar. The reassembly includes an attempt to undo strike-slip on the Southern Trans-Africa Shear System. This cryptic tectonic transcontinental corridor, which first formed as a Pan-African shear belt 700–500 Ma, also displays demonstrable dextral and sinistral movement between 300 and 200 Ma, not only evident in the alignment of the unsuccessful Karoo rifts now mapped from Tanzania to Namibia but also having an effect on many of the eventually successful rifts between Africa-Arabia and East Gondwana. We postulate its continuation into the Tethys Ocean as a major transform or megashear, allowing minor independence of movements between West Gondwana (partnered across the Tethys Ocean with Europe) and East Gondwana (partnered with Asia), Europe and Asia being independent before the 250 Ma consolidation of the Urals suture. The relative importance of primary driving forces, such as subduction ‘pull’, and ‘jostling’ forces experienced between adjacent rigid fragments could be related to plate size, the larger plates being relatively closely-coupled to the convecting mantle in the global scheme while the smaller ones may experience a preponderance of ‘jostling’ forces from their rigid neighbours.  相似文献   

Impact of AWS observations in WRF-3DVAR data assimilation system: a case study on abnormal warming condition in Odisha     

S. K. Dash  Dipak K. Sahu  S. C. Sahu 《Natural Hazards》2013,65(1):767-798

An abnormal warming condition with 3?C5?°C rise in temperature above its normal value was observed in the Indian state of Odisha during 12?C16 November 2009. This study aims at examining the impact of additional weather observations obtained from the automatic weather stations (AWS) installed in the recent past on the numerical simulation of such abnormal warming. AWS observations, such as temperature at 2?m (T2m), dew point temperature at 2?m (Td2m), wind vector at 10?m (speed and direction), and sea level pressure (SLP) have been assimilated into the state-of-the-art Weather Research and Forecasting (WRF) model using the three-dimensional variational data assimilation (3DVAR). Six sets of experiments have been conducted here. There is no data assimilation in the control experiment, whereas AWS and radiosonde observations have been assimilated in rest of the five experiments. The model integrations have been made for 72?h in each experiment starting from 0000 UTC November 12 to 0000 UTC November 15, 2009. Assimilation experiments have also been performed to assess the impact of individual surface parameters on the model simulations. Impact of AWS observations on model simulation has been examined with reference to the control simulation and quantified in terms of root-mean-square error and forecast skill score for temperature, sea level pressure, and relative humidity at three selected stations Bonaigarh, Brahmagiri, and Nuapada in Odisha. Results indicate improvements in the surface air temperature and SLP simulations in the timescale of 72?h at all the three stations due to additional weather data assimilation into the model. Improvements in simulation are significant up to 24?h. The assimilation of additional wind fields significantly improved the temperature simulation at all the three stations. The simulated SLP has also improved significantly due to the assimilation of surface temperature and moisture.  相似文献   

Groundwater arsenic contamination in Ganga–Meghna–Brahmaputra plain, its health effects and an approach for mitigation     

Dipankar Chakraborti  Mohammad Mahmudur Rahman  Bhaskar Das  Bishwajit Nayak  Arup Pal  Mrinal Kumar Sengupta  Md. Amir Hossain  Sad Ahamed  Manabendranath Sahu  Kshitish Chandra Saha  Subhash Chandra Mukherjee  Shyamapada Pati  Rathindra Nath Dutta  Quazi Quamruzzaman 《Environmental Earth Sciences》2013,70(5):1993-2008

The authors’ survey of the Ganga–Meghna–Brahmaputra (GMB) plain (area 569,749 km²; population >500 million) over the past 20 years and analysis of more than 220,000 hand tube-well water samples revealed groundwater arsenic contamination in the floodplains of the Ganga–Brahmaputra river (Uttar Pradesh, Bihar, Jharkhand, West Bengal, and Assam) in India and the Padma–Meghna–Brahmaputra river in Bangladesh. On average, 50 % of the water samples contain arsenic above the World Health Organization guideline value of 10 μg/L in India and Bangladesh. More than 100 million people in the GMB plain are potentially at risk. The authors’ medical team screened around 155,000 people from the affected villages and registered 16,000 patients with different types of arsenical skin lesions. Arsenic neuropathy and adverse pregnancy outcomes have been recorded. Infants and children drinking arsenic-contaminated water are believed to be at high risk. About 45,000 biological samples analyzed from arsenic-affected villages of the GMB plain revealed an elevated level of arsenic present in patients as well as non-patients, indicating that many are sub-clinically affected. In West Bengal and Bangladesh, there are huge surface water in rivers, wetlands, and flooded river basins. In the arsenic-affected GMB plain, the crisis is not over water scarcity but about managing the available water resources.  相似文献   

Impacts on groundwater recharge areas of megacity pumping: analysis of potential contamination of Kolkata,India, water supply     

Paulami Sahu  Holly A. Michael  Clifford I. Voss  Pradip K. Sikdar 《水文科学杂志》2013,58(6):1340-1360

Abstract

Water supply to the world’s megacities is a problem of quantity and quality that will be a priority in the coming decades. Heavy pumping of groundwater beneath these urban centres, particularly in regions with low natural topographic gradients, such as deltas and floodplains, can fundamentally alter the hydrological system. These changes affect recharge area locations, which may shift closer to the city centre than before development, thereby increasing the potential for contamination. Hydrogeological simulation analysis allows evaluation of the impact on past, present and future pumping for the region of Kolkata, India, on recharge area locations in an aquifer that supplies water to over 13 million people. Relocated recharge areas are compared with known surface contamination sources, with a focus on sustainable management of this urban groundwater resource. The study highlights the impacts of pumping on water sources for long-term development of stressed city aquifers and for future water supply in deltaic and floodplain regions of the world.

Editor D. Koutsoyiannis

Citation Sahu, P., Michael, H.A., Voss, C.I., and Sikdar, P.K., 2013. Impacts on groundwater recharge areas of megacity pumping: analysis of potential contamination of Kolkata, India, water supply. Hydrological Sciences Journal, 58 (6), 1340–1360.  相似文献   

Photometric study of type Ia supernova SN 2002hu     

D. K. Sahu  G. C. Anupama  T. P. Prabhu 《Monthly notices of the Royal Astronomical Society》2006,366(2):682-688

Optical UBVRI photometry of the type Ia supernova (SN Ia) SN 2002hu covering the period from −2 to +73 d since B maximum is presented. The supernova reached at maximum brightness in B on  JD 245 2591.78 ± 0.5  with an apparent magnitude of  16.83 ± 0.02 mag  and a relatively blue colour  ( B − V ) =−0.08 ± 0.04 mag  . The luminosity decline rate of  Δ m ₁₅( B ) = 1.00 ± 0.05  indicates an absolute B magnitude at maximum of   M ^max _B =−19.38 ± 0.3  . The estimated absolute B magnitude, together with the photometric evolution, indicate SN 2002hu was slightly overluminous compared to the average SNe Ia. The distance modulus to the parent galaxy is estimated to be  μ= 36.04 ± 0.20  .  相似文献   

A flattening in the optical light curve of SN 2002ap     

S. B. Pandey  &#;  G. C. Anupama  R. Sagar  D. Bhattacharya  D. K. Sahu  J. C. Pandey 《Monthly notices of the Royal Astronomical Society》2003,340(2):375-380

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Micro and Macro Cosmological Model in Barber's Second Self-Creation Theory     

G. Mohanty  R.C. Sahu  U.K. Panigrahi 《Astrophysics and Space Science》2003,284(3):1055-1062

A spatially homogeneous anisotropic Bianchi type-I cosmological model in the Barber's second self-creation theory is constructed when the gravitational field is generated by a mixture of micro and macro matter fields represented by meson field and perfect fluid respectively. The physical and geometrical features of the micro and macro cosmological model are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献