Surfactants enhanced recovery of endosulfan from contaminated soils   总被引：1，自引：1，他引：1  

R. Jayashree Ph.D.  N. Vasudevan  S. Chandrasekaran 《International Journal of Environmental Science and Technology》2006,3(3):251-259

Soil pollution due to hydrophobic organic compounds is a wide environmental problem. Extensive use of endosulfan in cotton and paddy to meet the needs of the growing population has led to contamination of soil and other ecosystems. Endosulfan is hydrophobic, highly toxic to aquatic and human population and persists in soil for more than a year. To overcome the problem of hydrophobicity and limited availability, surfactants play a major role in soil remediation. In the present study, the potential of non-ionic synthetic surfactants (Tween 80, Triton X-100) and biosurfactant (Surfactin produced by Bacillus subtilis) for enhancing the release of endosulfan from contaminated agricultural soils was evaluated using the batch method. Incorporation of the surfactant concentrations at above Criticle Miceller Concentration (0.5, 1 and 2 g/L) into soil enhances the release of endosulfan. Surfactin produced from Bacillus subtilis recorded maximum (91.5%) recovery. The observed order of recovery being surfactin > Tween 80 > Triton X-100. The result suggest that surfactants could help in the remediation of soils polluted by pesticides.  相似文献   

Groundwater quality in a coastal area: a case study from Andhra Pradesh, India     

N. Subba Rao  I. Saroja Nirmala  K. Suryanarayana 《Environmental Geology》2006,49(5):793-793

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Adaptation of seismic skeletonization for other geoscience applications     

K. Vasudevan  D. Eaton  F. A. Cook 《Geophysical Journal International》2005,162(3):975-993

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Geospatial landslide inventory of India—an insight into occurrence and exposure on a national scale     

Martha  Tapas Ranjan  Roy  Priyom  Jain  Nirmala  Khanna  Kirti  Mrinalni  K.  Kumar  K. Vinod  Rao  P. V. N. 《Landslides》2021,18(6):2125-2141

Landslides - India ranks first in the world in terms of fatal landslides. Large vulnerable area (0.42 million km2), high population density and monsoon rainfall make India’s landslide...  相似文献   

Piecing together the X-ray background: bolometric corrections for active galactic nuclei     

R. V. Vasudevan  A. C. Fabian 《Monthly notices of the Royal Astronomical Society》2007,381(3):1235-1251

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Reactivating Balia Nala landslide,Nainital, India—a disaster in waiting     

Roy  Priyom  Jain  Nirmala  Martha  Tapas R.  Kumar  K. Vinod 《Landslides》2022,19(6):1531-1535

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Multivariate statistical analysis of geochemical data of groundwater in Veeranam catchment area,Tamil Nadu   总被引：1，自引：0，他引：1  

M. Suvedha  B. Gurugnanam  M. Suganya  S. Vasudevan 《Journal of the Geological Society of India》2009,74(5):573-578

The study of hydrogeochemistry of the Mio-Pliocene sedimentary rock aquifer system in Veeranam catchment area produced a large geochemical dataset. Groundwater samples were collected at 52 sites over 963.86 km² area and analyzed for major ions. The large number of data can lead to difficulties in the integration, interpretation and representation of the results. Two multivariate statistical methods, Hierarchical cluster analysis (HCA) and Factor analysis (FA), were applied to a subgroup of the dataset to evaluate their usefulness to classify the groundwater samples, and to identify geochemical processes controlling groundwater geochemistry. Hydrochemical data for 52 groundwater samples were subjected to Q- and R- mode factor and cluster analysis. R-mode analysis reveals the inter-relations among the variables studied and the Q-mode analysis reveals the inter-relations among the samples studied. The R-mode factor analysis shows that Ca, Mg and Cl with HCO₃ account for most of the electrical conductivity, total dissolved solids and total hardness of groundwater. The ‘single dominance’ nature of the majority of the factors in the R-mode analysis indicates non-mixing or partial mixing of different types of groundwater. Both Q-mode factor and Q-mode cluster analyses indicate an exchange between the river water and the groundwater in the vicinity. The rock water interaction like flood basin back swamp deposits of silty clayey formation is the major cause for the cluster II classification. Cluster classification map reveals that 58% of the study area comes under cluster II classification.  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   

Searching of toxic metal pollution by using geospatial technology on the Kodaikanal Lake—near industrial area     

Balamurugan Palani  Sivaprakasam Vasudevan  Thirunavukkarasu Ramkumar 《Arabian Journal of Geosciences》2017,10(20):449

The present study investigates the anthropogenic metal input into the lake system, the toxic metal pollution in the sediments of Kodaikanal Lake. Surface sediment samples were collected at seven locations to represent its spatial variability within the lake. Samples were subjected to analyze for Fe, Co, Cr, Mn, Ni, Zn, Cd, Cu, Ag, Pb, Hg, and As by energy dispersive X-ray fluorescence (EDXRF) and their concentrations in lake sediments range from 102,000–109,000, 561–2699, 292–544, 211–482, 79–163, 57–265, 57–74, 37–92, 46–59, 20–97, 19–30, to 13–24 mg/kg, respectively. The sources of pollution were inferred through spatial and statistical analyses. Most of the toxic metal contents in the sediments are found to exceed the background concentration in all locations. The enrichment factor (EF) and index of geoaccumulation (I _geo) of Hg, Co, Cd, and Ag showed that sediments of Kodaikanal Lake exhibit the probability of anthropogenic influence. The significant Pearson’s correlation coefficient is also suggesting that they probably originated from the same source of occurrence. The contamination factor and degree of contamination of the Kodaikanal Lake sediments are strongly polluted in terms of most of the examined metals. The study also provides environmentally significant information about anthropogenic influence on the lake sediments.  相似文献   

Introduction: A symposium on Global Shadows: Africa in the Neoliberal World Order     

Alex Jeffrey  Colin McFarlane  Alexander Vasudevan 《Singapore journal of tropical geography》2008,29(3):251-253

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