Geochemical characterization and heavy metal contamination of groundwater in Satluj River Basin   总被引：1，自引：0，他引：1  

Chander Kumar Singh  Kumari Rina  Ravi Prakash Singh  Saumitra Mukherjee 《Environmental Earth Sciences》2014,71(1):201-216

Groundwater, a renewable and finite natural resource, vital for man’s life, social and economic development and a valuable component of the ecosystem, is vulnerable to natural and human impacts. The aim of present study is to evaluate hydrogeochemical parameters and heavy metals in groundwater and to study their spatial distribution in the Rupnagar District of Punjab. The spatial distribution of physico-chemical parameters were studied using Arc GIS 9.2. It was observed that the concentration of parameters, such as NO₃, Cd, Cr, Mn and Pb was above permissible limit (World Health Organization, WHO) in southern part of the study area. The heavy metal pollution index (HPI) was calculated for all sampling locations and it was found much above the critical limit of pollution. Geochemical reaction models of selected water groups were constructed using Phreeqc. Geochemical modeling suggests that sodium has source other than halite-albite and calcium has alternate source other than gypsum-carbonate or silicates. It also suggests that evaporites, ion exchange, dissolution along with anthropogenic activities are controlling the hydro-geochemistry of groundwater in the region. Various indices, such as heavy metal pollution index, permeability index, sodium adsorption ratio, were studied to verify suitability of groundwater for drinking and irrigation.  相似文献   

Anoxia over the western continental shelf of India: bacterial indications of intrinsic nitrification feeding denitrification     

Krishnan KP  Fernandes SO  Loka Bharathi PA  Krishna Kumari L  Nair S  Pratihary AK  Rao BR 《Marine environmental research》2008,65(5):445-455

Studies on the Arabian Sea coastal anoxia have been of immense interest, but despite its ecological significance there is sparse understanding of the microbes involved. Hence, observations were carried out off Goa (15 degrees 30'N, 72 degrees 40'E to 15 degrees 30'N, 72 degrees 59'E) to understand the processes that mediate the changes in various inorganic nitrogen species in the water column during anoxia. Water column chemistry showed a clear distinct oxic environment in the month of April and anoxic condition in October. Our study based on microbial signatures indicated that oxygen deficit appeared as a well-defined nucleus almost 40 km away from the coast during the oxic period (April) and spreads there after to the entire water column synchronizing with the water chemistry. Striking results of net changes in inorganic nitrogen species in nitrification blocked and unblocked experimental systems show that denitrification is the predominant process in the water column consuming available nitrate ( approximately 0.5 microM) to near zero levels within approximately 72 h of incubation. These observations have been supported by concomitant increase in nitrite concentration ( approximately 4 microM). Similar studies on denitrification-blocked incubations, demonstrate the potential of nitrification to feed denitrification. Nitrification could contribute almost 4.5 microM to the total nitrate pool. It was found that the relation between ammonium and total dissolved inorganic nitrogen (DIN) pool (r=0.98, p<0.001, n=122) was significant compared to the latter with nitrite and nitrate. The occurrence of high ammonium under low phosphate conditions corroborates our observations that ammonium does not appear to be locked under low oxygen regimes. It is suggested that ammonium actively produced by detrital breakdown (ammonification) is efficiently consumed through nitrification process. The three processes in concert viz. ammonification, nitrification and denitrification appear to operate in more temporal and spatial proximity than hitherto appreciated in these systems and this gives additional cues on the absence of measurable nitrate at surface waters, which was earlier attributed only to efficient algal uptake. Hence we hypothesize that the alarming nitrous oxide input into the atmosphere could be due to high productivity driven tighter nitrification-denitrification coupling, rather than denitrification driven by extraneous nitrate.  相似文献   

Some Inhomogeneous Perfect Fluid Cosmological Models in the Presence of Electromagnetic Field     

Ghanshyam Singh  Preeti Mehta  Suman Gupta 《Astrophysics and Space Science》2002,281(4):677-688

Some cylindrically symmetric inhomogeneous cosmological models for perfect fluid distributions with electromagnetic field are obtained. To get a determinate solution, a supplementary condition between metric potentials is used. Various physical and geometrical properties of the models with some special cases are also discussed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Implementation of RISAT-1 Hybrid Polarimetric Decomposition Techniques and Analysis Using Corner Reflector Data     

P. V. Jayasri  K. Niharika  Manoj Joseph  H. S. V. Usha Sundari Ryali  C. V. Ramana Sarma  E. V. S. Sita Kumari  A. V. V. Prasad 《Journal of the Indian Society of Remote Sensing》2018,46(6):1005-1012

With recent advances in polarimetry, Synthetic Aperture Radar (SAR) with Hybrid–polarity architecture, a demonstration of compact polarimetry enabled larger swath coverage, reduced PRF and SAR system complexity as compared to fully polarimetric systems. The first Hybrid Polarimetric Space-borne SAR in Earth Observation orbit, India’s Radar Imaging Satellite (RISAT-1) is a new-fangled gateway to remote sensing user community for land and oceanic applications. In response to a right-circular polarized transmitted signal, based on the derived stokes vectors, Stokes parameters are estimated to produce several useful quantitative measures for generating polarimetric decomposed image. m-delta, m-chi and m-alpha polarimetric decomposition methods along with suitable weighting functions in terms of three principal components are implemented which maps Stokes parameters to RGB image space for representing odd bounce, even bounce and volume scattering targets. Various RISAT-1 Hybrid Fine Resolution Stripmap Single-Look Complex SAR datasets acquired over deployed corner reflectors at calibration site, Shadnagar have been considered over which different hybrid polarimetric decomposition techniques are implemented using in-house developed software. Further analysis produced encouraging results with standard point targets like dihedral and trihedral corner reflectors against distributed targets in the same scene to demonstrate the scattering mechanisms as per their characteristics when interacted with a polarized signal were presented in this paper.  相似文献   

Effect of linear waves on kinetic Alfvén wave localization and turbulent spectrum     

Anju Kumari  Nitin Yadav  R. P. Sharma 《Astrophysics and Space Science》2014,352(1):201-206

We have presented the localization of kinetic Alfvén wave (KAW) in intermediate β plasma (m _e /m _i ?β?1) by developing a model based on pump kinetic Alfvén wave and finite amplitude magnetosonic fluctuations. When KAW is perturbed by these background magnetosonic fluctuations, filamentary structures of KAW magnetic field are formed. First, a semi analytical model based on paraxial approximation has been developed to understand this evolution process. Localized structures and magnetic fluctuation spectrum of KAW has also been studied numerically for finite frequency of KAW. The calculated magnetic fluctuation spectrum follows two types of scalings. Above the proton gyroradius scale lengths (in inertial range), spectrum follows Kolmogorovian scaling. Below this scale dispersion starts and the spectrum steepens to about \(k_{x}^{-2.5}\) . The result shows the steepening of power spectra which can be responsible for particle acceleration in solar wind due to the energy transfer from larger to smaller lengthscales. Obtained magnetic turbulent spectra are consistent with observations of Cluster spacecraft in solar wind.  相似文献   

A restudy of the Ostracoda <Emphasis Type="Italic">Cypris cylindrica</Emphasis> Sowerby (in Malcolmson, 1840) from the Deccan Intertrappean beds (late cretaceous) of Lakshmipur,Kachchh, Gujarat     

S. C. Khosla  M. L. Nagori  S. R. Jakhar  A. S. Rathore  Manisha Kumari 《Journal of the Geological Society of India》2009,74(5):579-584

Cypris cylindrica was originally described by Sowerby (in Malcolmson, 1840) from the Deccan Intertrappean sedimentary beds of the Sichel Hills, Andhra Pradesh. Whatley and Bajpai (2000) recorded the species during recent years from the Intertrappean of Lakshmipur, Kachchh district, Gujarat and stated that Kachchh specimens are identical with the types of the species housed in the Natural History Museum (NHM), London. They recorded the species as Mongolianella cylindrica. The species, however, lacks distinctive shape and hinge structure of Mongolianella and on the contrary closely resembles Stenocypris cylindrica major (Baird, 1859) in shape and internal characters including having adont hinge, large anterior vestibulum, arcuate lists or striae on free part of inner lamella, numerous short marginal pore canals and 6 large adductor scars, the topmost being much elongated. On these bases the species is herein transferred to the genus Stenocypris Sars, 1889.  相似文献   

Correction to: Trace ambient levels of particulate mercury and its sources at a rural site near Delhi     

Anita Kumari  Umesh Kulshrestha 《Journal of Atmospheric Chemistry》2018,75(4):357-357

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A Comprehensive Review on Microalgae-Based Biorefinery as Two-Way Source of Wastewater Treatment and Bioresource Recovery     

Sumira Malik  Shristi Kishore  Jutishna Bora  Vishal Chaudhary  Anjali Kumari  Preeti Kumari  Lamha Kumar  Abhaya Bhardwaj 《洁净——土壤、空气、水》2023,51(3):2200044

In the past few years, microalgae have gained huge recognition from the scientific community due to their potential applications in the production of a broad array of bio-based products varying from biofuels to nanoparticles. Due to their elevated growth rate, high tolerance to various types of abiotic stresses, and complex metabolic capacity, microalgae can be used as promising tools for the attainment of a circular bioeconomy. Moreover, they can simply utilize nutrients from wastewater for biorefinery purposes, resulting in resource recovery coupled with wastewater treatment. However, due to their sub-optimal yields and high production costs, microalgae-based bio-products have not yet been commercialized. This review provides insights into the employment of microalgae as an efficient bioresource for the treatment of wastewater with simultaneous enactment as a biorefinery to produce biofuels, biochar, bioplastic, fertilizers, and other high-value bioproducts. Furthermore, the application of microalgal nanoparticles in wastewater treatment and prospects for genetic modification of microalgae for enhanced biorefinery capabilities have also been briefly highlighted.  相似文献   

Magnetoelastic shear wave propagation in pre-stressed anisotropic media under gravity     

Nirmala Kumari  Amares Chattopadhyay  Abhishek K. Singh  Sanjeev A. Sahu 《Acta Geophysica》2017,65(1):189-205

The present study investigates the propagation of shear wave (horizontally polarized) in two initially stressed heterogeneous anisotropic (magnetoelastic transversely isotropic) layers in the crust overlying a transversely isotropic gravitating semi-infinite medium. Heterogeneities in both the anisotropic layers are caused due to exponential variation (case-I) and linear variation (case-II) in the elastic constants with respect to the space variable pointing positively downwards. The dispersion relations have been established in closed form using Whittaker’s asymptotic expansion and were found to be in the well-agreement to the classical Love wave equations. The substantial effects of magnetoelastic coupling parameters, heterogeneity parameters, horizontal compressive initial stresses, Biot’s gravity parameter, and wave number on the phase velocity of shear waves have been computed and depicted by means of a graph. As a special case, dispersion equations have been deduced when the two layers and half-space are isotropic and homogeneous. The comparative study for both cases of heterogeneity of the layers has been performed and also depicted by means of graphical illustrations.  相似文献   

Emergence of the semi-empirical technique of strong ground motion simulation: A review     

Sandeep  A. Joshi  P. Kumari  S. Lal  Vandana  Parveen Kumar  Kamal 《Journal of the Geological Society of India》2017,89(6):719-722

High frequency ground motion simulation techniques are powerful tools for designing earthquake resistant structures in seismically active regimes. Simulation techniques also provide the synthetic strong ground motion in the regions where actual records are not available (Kumar et al. 2015).These techniques require several parameters of earthquake and other seismic information proceeding to the simulation. Practically estimation of parameters is a tough task, particularly in a region with limited information. This demands a simulation technique based on the easily estimated parameters for a new site. The purposes of this paper are to briefly review existing simulation techniques and to discuss in detail the new, simple and effective semi-empirical technique (Midorikawa 1993) of strong motion simulation.  相似文献