Fluoride contamination of groundwater and its seasonal variability in parts of Purulia district,West Bengal,India     

Syed Hilal Farooq  Pintu Prusty  Raj Kumar Singh  Subhajit Sen  Dornadula Chandrasekharam 《Arabian Journal of Geosciences》2018,11(22):709

The contamination of aquifers by fluoride and arsenic is a major cause of concern in several parts of India. A study has thus been conducted to evaluate the extent and severity of fluoride contamination and also its seasonal variability. Two blocks (Purulia-1 and Purulia-2) were considered for this purpose. Twenty groundwater samples (in each season) were collected from tube wells during the pre-monsoon and post-monsoon seasons. In addition to fluoride, groundwater samples were also analyzed for major cations, anions, and other trace elements. The concentration of fluoride shows significant seasonal variation and ranges between 0.94–2.52 and 0.25–1.43 mg/l during the pre-monsoon and post-monsoon seasons, respectively. In pre-monsoon season, more than 40% of the water samples show fluoride concentrations higher than the WHO limit. However, during the post-monsoon season, none of the groundwater sample shows fluoride concentrations higher than the WHO limit. Lesser concentration during the post-monsoon season is attributed to the dilution effect by the percolating rainwater, which has also been reflected in the form of a decrease in concentrations of other elements. The petrographic studies of the rock samples collected from the study area show that the rocks are mainly composed of plagioclase, orthoclase, and quartz with abundant biotite. The weathering and dissolution of biotite plays an important role in controlling the fluoride concentrations in the groundwater of the study area.  相似文献   

Correction to: vegetation damage assessment due to Hudhud cyclone based on NDVI using Landsat-8 satellite imagery     

Venkata Giri Raj Kumar Konda  Venkatesh Reddy Chejarla  Venkata Ravibabu Mandla  Vani Voleti  Nagaveni Chokkavarapu 《Arabian Journal of Geosciences》2018,11(3):67

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Assessment of groundwater potential zones in coal mining impacted hard-rock terrain of India by integrating geospatial and analytic hierarchy process (AHP) approach   总被引：2，自引：0，他引：2  

Akshay Kumar  Akhouri Pramod Krishna 《国际地球制图》2018,33(2):105-129

The study aims at delineating groundwater potential zones using geospatial technology and analytical hierarchy process (AHP) techniques in mining impacted hard rock terrain of Ramgarh and part of Hazaribagh districts, Jharkhand, India. Relevant thematic layers were prepared and assigned weight based on Saaty’s 9-point scale and normalized by eigenvector technique of AHP to identify groundwater prospect in the study area. The weighted linear combination method was applied to prepare the groundwater potential index in geographic information system. Final groundwater prospects were classified as excellent, very good, good, moderate, poor and very poor groundwater potential zones. Study thus revealed that the excellent, very good and good groundwater potential zones, respectively, cover 148.3, 373.66 and 438.86 km² of the study area, whereas the poor groundwater potential zone covers 180.05 km². Validation was done through a receiver operating characteristic curve, which indicated that AHP had good prediction accuracy (AUC = 75.45%).  相似文献   

Investigating the association between streetscapes and human walking activities using Google Street View and human trajectory data   总被引：1，自引：0，他引：1       下载免费PDF全文

Xiaojiang Li  Paolo Santi  Theodore K. Courtney  Santosh K. Verma  Carlo Ratti 《Transactions in GIS》2018,22(4):1029-1044

Having an active lifestyle is recognized to positively contribute to public health. Creating more walkable streets and neighborhoods is an important way to promote an active lifestyle for urban residents. It is therefore important to understand how the urban built environment can influence human walking activities. In this study, we investigated the interaction of human walking activities and physical characteristics of streetscapes in Boston. A large number of anonymous pedestrian trajectories collected from a smartphone application were used to estimate human walking activities. Publicly accessible Google Street View images were used to estimate the amount of street greenery and the enclosure of street canyons, both of which were used to indicate the physical characteristics of streetscapes. The Walk Score and population were also added in the statistical analyses to control the influence of nearby urban facilities and population on human walking activities. Statistical analysis results show that both the street greenery and the enclosure of the street canyons are significantly associated with human walking activities. The associations between the streetscape variables and human walking activities vary in different land use types. The results of this study have implications for designing walkable and healthy cities.  相似文献   

Subduction initiation of Indochina and South China blocks: insight from the forearc ophiolitic peridotites of the Song Ma Suture Zone in Vietnam     

Thanh Xuan Ngo  M. Santosh  Hai Thanh Tran  Hieu Trung Pham 《Geological Journal》2016,51(3):421-442

The Song Ma region, which is located in the northwestern Vietnam represents the zone of amalgamation between Indochina and South China blocks. Numerous scattered ultramafic rocks occur in this region in association with Early to Middle Palaeozoic greenschists and paragneisses, and all these rocks were subjected to hydrous metamorphism and deformation. Here, we present new field data, mineral chemistry and geochemistry from a suite of hydrated peridotites within the Song Ma region and discuss the tectonic significances of the region. We also combine the available data within the Song Ma region and Indochina–South China blocks to discuss the tectonic evolution of the subduction zone. Based on the results, we suggest that the peridotites from the Song Ma are mantle residues that suffered a high degree of partial melting in a forearc tectonic setting. The present data together with the available data within the Song Ma region and the Indochina and South China blocks clearly represent a southward directed Middle Palaeozoic subduction system. The Middle Palaeozoic subduction and accretion events mark the evolutionary history along an active convergent margin between the Indochina and South China blocks, possibly related to the amalgamation of the Pangaea supercontinent. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Recent trends in vegetation dynamics in the South America and their relationship to rainfall   总被引：2，自引：2，他引：0  

H. A. Barbosa  T. V. Lakshmi Kumar  L. R. M. Silva 《Natural Hazards》2015,77(2):883-899

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Fractal study of seismicity in order to characterize the various tectonic blocks of North-east Himalaya,India     

P. N. S. Roy  Suparna Chowdhury  Partha Sarkar  Saroj Kumar Mondal 《Natural Hazards》2015,77(1):5-18

North-eastern Himalaya is said to be one of the world most complex geological set-up with different kinds of seismotectonic systems. Region has experienced two of the world’s strongest earthquakes, such as Shillong earthquake of 1897 known as Assam earthquake and subsequent 1950 earthquake in Arunachal Pradesh, both of with magnitude of 8.7, and also several other strong earthquakes. Various techniques have been applied to understand the past strong earthquake mechanism as well as hazard estimation carried out for future earthquake. Fractal correlation dimension (D _c) is being used in this study with the seismicity for the period 1961 to recent for understanding the pattern of seismic hazard. The entire area has been divided into four major tectonic blocks, and each block event was divided into consecutive fifty events window for seeing spatiotemporal patterns. After comparing the patterns, we have identified that Block of Eastern Himalaya near Main Central Thrust, Main Boundary Thrust, north of Kopili lineament and Block of Shillong plateau near Dauki fault are having relatively intense clustering of events in recent times, which may be identified as the zones of most potential to have a strong event.  相似文献   

Spatial and temporal variations of wave height in shelf seas around India   总被引：1，自引：1，他引：0  

V. Sanil Kumar  T. R. Anoop 《Natural Hazards》2015,78(3):1693-1706

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MHD free and forced convection flow past an infinite vertical plate with heat source     

Basant Kumar Jha 《Astrophysics and Space Science》1991,183(2):169-175

An analytical study is performed to examine the effects of magnetic field and temperature-dependent heat source on the free and forced convection flow past an infinite vertical plate. The expressions for the velocity field, penetration distance and skin-friction have been obtained by Laplace transform technique. The influence of the various parameters entering into the problem is extensively discussed.  相似文献   

Role of geophysical and hydrogeological techniques in EIA studies to identify TSDF site for industrial waste management   总被引：2，自引：0，他引：2  

Sahebrao Sonkamble  S. Sethurama  K. Krishnakumar  Purushottam Dhunde  B. Amarender  V. Satish Kumar 《Journal of the Geological Society of India》2013,81(4):472-480

This paper deals with the importance of integrated hydrogeological, geological and geophysical applications in identifying suitable site for treatment, storage and disposal facility (TDSF) for industrial waste management. The pollution control authorities (Civic body) have a mandate to provide proper TSDF for the industrial zones. One such zone of 2800 acres, established by State Industries Promotion Corporation of Tamil Nadu (SIPCOT) at Perundurai in southern India, is selected to identify suitable TSDF site. The zone is envisaged to cater 22500 MTA (metric tones per annum) of industrial waste generated by 565 units. Hydrogeological and geological setup forms an important criterion in the process of environmental impact assessment (EIA) to establish proposed activity. Hydrogeological, geophysical and socio-economic/ecological studies were carried out to identify suitable TSDF site. Vertical electrical sounding (VES), multi-electrode resistivity imaging (MERI), ground penetrating radar (GPR) scanning, and infiltration tests were performed within the proposed TSDF site of 50 acres land. An inventory of 54 key wells includes depth to water level (varies from 9.7 to 15 m, below ground level) and water chemistry (pH, TDS, Ca²⁺, Mg²⁺, Na⁺, K⁺, Cl^?, HCO ₃ ^? , SO ₄ ^2? , NO ₃ ^? and F^?) helped in identifying physical environment around (5 km radius) proposed TSDF site. Geophysical and hydrogeological investigations verified with drillings (at 5 locations) within the proposed TSDF site resulted, shallow hard rock at 4.5 m depth, the absence of groundwater, and low infiltration rate (4.3 cm/hour) of soil in the western side (45 acres) of proposed 50 acres land reveals suitability of TSDF site.  相似文献