Browsing by Author "Sangita Dey"

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Appraisal of groundwater potentiality of multilayer alluvial aquifers of the Varuna river basin, India, using two concurrent methods of MCDM
(Springer Science and Business Media B.V., 2021) Sangita Dey; U.K. Shukla; P. Mehrishi; R.K. Mall
An approach has been made in this study to delineate the groundwater potential zones of the Varuna river basin, Uttar Pradesh, India, using the analytical hierarchy process (AHP) and multi-influence factor (MIF) techniques. The present groundwater estimation exhibits an increase in the draft (10%) due to expansion in population, agricultural extent, and industrialization, which ultimately causes water table depletion. This backdrop justifies the need for this particular analysis in the multilayer aquifers of the central alluvial zone. The shallow aquifers are silty and unconfined, whereas the deeper aquifers are coarse, sandy-gravelly, and semi-confined. Basement faults and highs often control the thickness of aquifers in the subsurface. The study considered an integrated approach of AHP and MIF methods with remote sensing and GIS approaches. Various themes (land use/land cover (LULC), soil type, geology, elevation, slope, rainfall, normalized difference vegetation index (NDVI), drainage density, recharge rate, groundwater depth) determined by considering different conditioning factors and eventually employed for computation of groundwater potential index (GWPI) and classified for identifying the groundwater potential zones (GWPZ). Two methods applied to capture the results in a more tangible form as the AHP model works on building a pair-wise comparison matrix to relate conditioning factors to each other. Still, the MIF model considered interrelations among the conditioning factors. The GWPZ of the study area generates with overlay weighted sum method by integrating all thematic layers. The resulting groundwater potential index map is categorized into three groundwater potential zones, namely good, moderate, and poor. Ultimately, by constructing the receiver operating characteristic (ROC) curves for both the groundwater potential models, determine the efficiency of performances and the GWPZ map validated using yield data collected from wells scattered over the study area. The findings of the present paper have important implications for ensuring exploration and sustainability groundwater plans in that particular area. © 2021, The Author(s), under exclusive licence to Springer Nature B.V.
Chronic exercise alters EEG power spectra in an animal model of depression
(1996) Suptendra Nath Sarbadhikari; Sangita Dey; Amit Kumar Ray
The EEG from frontal cortex, EMG and EEG were recorded from rats exposed to only exercise (Treadmill), only stress, exercise + stress and neither (control). In comparison with the control group, the percent of Delta activity in the awake was significantly increased in the depressed group and significantly decreased in the exercised groups, while for Beta-2, the reverse occurred; Theta increased and Beta-2 decreased in the NREM sleep state of the depressed group and the opposite happened for the exercised groups; Delta and Alpha-2 activity significantly increased in the depressed group, and they were significantly decreased in the exercised groups whereas the Beta-2 activity showed contrary changes in the REM sleep state. These findings indicate that exercise has the opposite effect from what stress has on qEEG and concomitant physical exercise reduces the effects of stress. Behavioral tests were done by Open Field (OF) and High Plus Maze (HPM). Slow EEG activity (Delta, Theta, Alpha) was significantly positively correlated with immobilization in the OF and defecation in both OF and HPM and negatively with the food intake, transfer latency in HPM; rearing, grooming and total ambulation in OF. Whereas, fast activity (Beta-2) was significantly negatively correlated with immobilization in OF and defecation in OF and HPM, while positively with ambulation in the central squares of OF and time spent at the central cross and number of times arms crossed in the HPM.
Exercise training: Significance of regional alterations in serotonin metabolism of rat brain in relation to antidepressant effect of exercise
(1992) Sangita Dey; R.H. Singh; P.K. Dey
Alterations of 5HT and its chief metabolite 5HIAA were studied in four regions of the rat brain following acute 1-h swim exercise and 4 week chronic swim exercise (30 min/day, 6 days per week). Acute exercise significantly increased the synthesis and metabolism of 5HT in brain stem. Hypothalamus also showed increased levels of 5HT. However, no changes were observed in the cerebral cortex and hippocampus. Chronic exercise activated not only the synthesis but also the metabolism of 5HT in the cerebral cortex; this neuronal adaptation was sustained even 1 week after the termination of training. In brain stem, increased 5HT turnover was observed immediately after training. In hypothalamus, decrease in 5HT and 5HIAA levels occurred immediately after training, followed by a rebound increase in their levels after 1 week posttraining rest. In hippocampus, a delayed effect was observed, because 5HT level was unaltered immediately after the training, but its turnover decreased after 1 week rest. These findings have been discussed in an attempt to explain the antidepressant effect of exercise based on the 5HT deficiency theory of endogenous depression. © 1992.
Fluoride contamination in groundwaters of Sonbhadra District, Uttar Pradesh, India
(2009) N. Janardhana Raju; Sangita Dey; Kaushik Das
Fluoride (F-) concentration over and above the permissible limits (1.5 mg/l) in drinking water leads to human health hazards, such as dental and skeletal fluorosis affecting millions of people in many parts of India. Preliminary investigations indicate that severe health disorders have been identified in parts of the Kachnarwa region, which is in the upper Panda river basin, Sonbhadra District, Uttar Pradesh, due to excess intake of fluoride through drinking water. The lithological units of the study area mainly consist of granite and gneissic complex rocks of the Chota-Nagpur Plateau. In order to understand the probable source of fluoride and its concentration, 17 groundwater samples mostly from granite and phyllite regions were collected for fluoride estimation during May 2006. The concentration of fluoride in the groundwater of the study area varies from 0.483 to 6.7 mg/l. Among the 17 samples analysed, 8 exceeded the maximum permissible limits of fluoride in the study area. The source of fluoride in the groundwater of the study area is mainly from geological occurrence (i.e. fluoridebearing minerals, viz. apatite and biotitic mica). Microscopic analysis of the rock samples showed 5-10% apatite and 20-25% biotite, but other fluoride-bearing minerals like fluorite and hornblende were characteristically absent. X-ray diffraction studies showed that apatite mineral peak profile of the rock samples corroborated with the fluorapatite of the standard set by the JCPDS. The worst fluoride-affected villages are Rohiniyadamar, Madhuri, Neruiyadamar, Gobardaha and Kunrwa. Most people in these villages suffer from dental and skeletal fluorosis such as mottling of teeth, deformation of ligaments, bending of spinal column and ageing problem. An urgent need is to educate the people on the causes of fluorosis, encouraging rainwater harvesting and providing fluoride-free drinking water in the study area.
Fluoride hazard and assessment of groundwater quality in the semi-arid Upper Panda River basin, Sonbhadra district, Uttar Pradesh, India; [Risques liés au fluor et évaluation de la qualité des eaux souterraines dans le bassin supérieursemi-aride de la rivìre Panda, district de Sonbhadra (Uttar Pradesh, Inde)]
(2012) N. Janardhana Raju; Sangita Dey; Wolfgang Gossel; Peter Wycisk
Around 9000 inhabitants in the Panda River basin, Sonbhadhra District, Uttar Pradesh, India, are vulnerable to a "silent" dental and skeletal fluorosis from groundwater consumption. The fluoride source and seasonal groundwater quality variation were studied by collecting 65 groundwater samples in the Upper Panda River basin. Major rock types are phyllites and granite gneissic rocks. Fluoride concentrations are in the range 0.4-5.6 mg/L in the pre-monsoon season and 0.1-6.7 mg/L in the post-monsoon season. Fluor-apatite and biotite mica in the granite gneissic rock were identified as the main provenance of fluoride in the groundwater through water-rock interactions. Due to precipitation of calcium, soils become alkaline with high contents of sodium; these conditions allow fluoride to accumulate in water. According to risk index calculations, the fluoride-affected villages were shown to fall in the fluoride risk zone (with a risk index of around 1.7). On the basis of mineral stability diagrams, groundwater from the weathered and fractured aquifers appears to be stable within the kaolinite field, suggesting weathering of silicate minerals. The groundwater is chemically potable and suitable for domestic and agricultural purposes, except for a few wells in the southern region that are contaminated with high amounts of fluoride.Editor D. KoutsoyiannisCitation Raju, N.J., Dey, S., Gossel, W., and Wycisk, P., 2012. Fluoride hazard and assessment of groundwater quality in the semi-arid Upper Panda River basin, Sonbhadra District, Uttar Pradesh, India. Hydrological Sciences Journal, 57 (7), 1433-1452. © 2012 Copyright 2012 IAHS Press.
Groundwater quality in the lower Varuna River basin, Varanasi district, Uttar Pradesh
(2009) N. Janardhana Raju; Prahlad Ram; Sangita Dey
The lower Varuna River basin in Varanasi district situated in the central Ganga plain is a highly productive agricultural area, and is also one of the fast growing urban areas in India. The agricultural and urbanization activities have a lot of impact on the groundwater quality of the study area. The river basin is underlain by Quaternary alluvial sediments consisting of clay, silt, sand and gravel of various grades. The hydrogeochemical study was undertaken by randomly collecting 75 groundwater samples from dug wells and hand pumps covering the entire basin in order to understand the sources of dissolved ions, and to assess the chemical quality of the groundwater through analysis of major ions. Based on the total dissolved solids, two groundwater samples are considered unsuitable for drinking purpose, but all samples are useful for irrigation. Graphical treatment of major ion chemistry by Piper diagram helps in identifying hydro-geochemical facies of groundwaters and the dominant hydrochemical facies is Ca-Mg-HCO3 with appreciable percentage of the water having mixed facies. As per Wilcox's diagram and US Salinity laboratory classification, most of the groundwater samples are suitable for irrigation except two samples (No's 30 and 68) which are unsuitable due to the presence of high salinity and medium sodium hazard. Irrigation waters classified based on residual sodium carbonate, have revealed that all groundwaters are in general safe for irrigation except one sample (No. 27), which needs treatment before use. Permeability index indicates that the groundwater samples are suitable for irrigation purpose. Although the general quality of groundwater of the lower Varuna River basin is suitable for irrigation purpose, fifty seven percent of the samples are found having nitrate content more than permissible limit (>45 mg/l) which is not good for human consumption. Application of N-Fertilizers on agricultural land as crop nutrients along the Varuna River course may be responsible for nitrate pollution in the groundwater due to leaching by applied irrigation water. The other potential sources of high nitrate concentration in extreme northern, southern and southwestern parts of study area are poor sewerage and drainage facilities, leakage of human excreta from very old septic tanks, and sanitary landfills. The high fluoride contamination (>1.5 mg/l) in some of the samples may be due to the dissolution of micaceous content in the alluvium. Nitrate and fluoride contamination of groundwater is a serious problem for its domestic use. Hence an immediate protective measure must be put into action in the study area. © Geol. Soc. India.
Hydrogeochemical assessment to explore the extent, nature and source of fluoride contamination within the groundwaters of the Panda River Basin, Sonbhadra district, Uttar Pradesh, India
(Capital Publishing Company, 2014) Sangita Dey; N.J. Raju
Significant amounts of fluoride are found in the abstracted groundwater of the southern part of the Upper Panda River basin, Sonbhadra district, Uttar Pradesh, India. Hence groundwater with high fluoride and water mixture patterns were studied in Panda River basin through hydrochemical interpretation from 65 groundwater chemical data information from different wells for both the seasons premonsoon and postmonsoon. The chemical relationship and Gibbs diagram suggest that the groundwaters mainly belong to freshwater, alkali type and are controlled by rock dominance; due to influence of semi arid condition and water rock inter action. Na-HCO3 is dominated in most part (60% of the total number of water samples for both the seasons) of the study area. The whole environment is favorable for the fluoride dissolution as the increasing Na concentrations are observed under alkaline conditions with a subsequent reduction in Ca concentration. Major rock types of the area are phyllites and granite gneissic rocks. Geochemical study reveals that Fluor-apatite and biotite mica in the granite gneissic rock is the main source of fluoride in the groundwater through water-rock interactions. Fluoride concentrations are in the range 0. 4-5. 6 μg/L in the pre-monsoon season and 0. 1-6. 7 μg/L in the postmonsoon season. Ion exchange, dissolution, semi-arid climate, alkaline conditions and weathering are responsible for fluoride enrichment in the groundwater of the study area. © 2014, Capital Publishing Company.
Hydrogeochemical characterisation and evaluation of seasonal variation in groundwater chemistry in upper Panda river Basin, India
(Springer International Publishing, 2015) Sangita Dey; N. Janardhana Raju; Prahlad Ram; Janmejoy Singh
The shortage of water resources of good quality is becoming an important issue in hard rock and semi-arid zones and rapid declining of groundwater supplies are common (Raju and Reddy, 2007). Groundwater is the primary source of water for domestic, agricultural and industrial uses in many countries, and its contamination has been recognised as one of the most serious problems in India (Raju, 2007; Reddy et al., 2010; Raju et al 2009a). Major ion-chemistry of ground water provides the basis to investigate the weathering reactions in the basin (Das and Kaur, 2007; Raju et al., 2011). Each groundwater system, in the area, has a unique chemistry, acquired as a result of chemical alteration of meteoric water recharging the system (Back, 1966; Drever, 1997; Raju, 2012). The assessment of the suitability of groundwater for domestic water supply requires knowledge of the concentrations of inorganic constituents and their comparison with existing standards. Irrigation water quality concerns the amounts of salts present in ground water and their effects on crop growth and development. Since there is no adequate surface water supply, about 80-90 % of drinking and irrigation use is from available groundwater resources and the importance of groundwater utilization has increased at an alarming rate in parts of Panda River basin, Sonbhadra district of Uttar Pradesh (Dey, 2010). Some parts of the study area are facing severe groundwater problems i.e. fluoride contamination which makes the water unfit for human consumption (Raju et al., 2009b). The main objective of the study is to assess spatial distribution of hydrogeochemical parameters and evaluate seasonal variation in groundwater chemistry of the upper Panda River basin, Sonbhadra district of Uttar Pradesh, India. © Capital Publishing Company 2015.
Hydrogeochemical characterization and geochemical modeling for the evaluation of groundwater quality and health risk assessment in the Varuna River basin, India
(Springer Science and Business Media B.V., 2023) Sangita Dey; N. Janardhana Raju; Wolfgang Gossel; R.K. Mall
This study focuses on determining significant controlling factors of chemical consequences, inverse geochemical modeling, water quality, and human health risk in the Varuna River basin of India. The study interprets that according to pH, total dissolved solids, and total hardness, the maximum number of groundwater samples are alkaline, fresh, and have substantial hardness. The abundance of major ions follows a pattern: Na > Ca > Mg > K, and HCO3 > Cl > SO4 > NO3 > F. Piper diagram shows that Ca–Mg–HCO3 facies are predominant during both seasons. Na-normalized molar ratios of HCO3/Na, Mg/Na, and Ca/Na are 0.62, 0.95, and 1.82 (pre-monsoon) and 0.69, 0.91, and 1.71 (post-monsoon), respectively, elucidating the coupled silicate and carbonate weathering (dolomite dissolution) sources. The Na/Cl molar ratio is 5.3 (pre-monsoon) and 3.2 (post-monsoon), indicating silicate alteration as the primary process rather than halite dissolution. The chloro-alkaline indices confirm the presence of reverse ion- exchange. Geochemical modeling using PHREEQC identifies the formation of secondary kaolinite minerals. The inverse geochemical modeling categorizes the groundwaters along the flow path from recharge area waters (Group I: Na–HCO3–Cl), transitional area waters (Group II: Na–Ca–HCO3), and discharge area waters (Group III: Na–Mg–HCO3). The model demonstrates the prepotency of water–rock interactions in pre-monsoon justified by the precipitation of Chalcedony and Ca-montmorillonite. The mixing analysis shows that in the alluvial plains, groundwater mixing is a significant hydrogeochemical process that affects groundwater quality. The Entropy Water Quality Index ranks 45% (pre-monsoon) and 50% (post-monsoon) of samples as an excellent category. However, the non-carcinogenic health risk assessment shows that children are more susceptible to fluoride and nitrate contamination. © 2023, The Author(s), under exclusive licence to Springer Nature B.V.
Hydrogeochemical characterization for groundwater quality and risk assessment in part of central gangetic alluvium, India
(Elsevier B.V., 2024) Sangita Dey; Saumya Singh; N. Janardhana Raju; R.K. Mall
An exponential growth in groundwater extraction will greatly concern the Varuna River basin of Central Ganga alluvium. This complex issue requires proper systematic evaluations to advocate various opportunities for management strategies for groundwater sustainability. The present study aims to convey scientific assessments of the groundwater using different soft-computing techniques to determine its hydrogeochemistry and quality for averting future risk and envisaging suitable management policies. SOM (Self-Organizing Map) model involves characterizing the spatial clusters of regional hydrogeochemistry and reported a gradual increase in salinity from the northwestern to the southeastern part of the area. PCA (Principal Component Analysis) provides evidence of rock-water interactions and anthropogenic activities as responsible factors in determining hydrogeochemistry. Quality assurance is judged by various systematic chemometric indices. CCMEWQI (Canadian Council of Ministers of the Environment Water Quality Index) and IWQI (Irrigation Water Quality Index) reveal that the groundwater is suitable for drinking/domestic and irrigation use. Continuous fluxes of freshwater nourish Gangetic alluvium and generally provide excellent quality. In contrast, the analysis results notice the degradation of drinking quality from the excellent to good category (CCMEWQI) and moderate to low restriction (IWQI) for irrigation suitability. Further study of potential health risks represents the presence of carcinogenic and non-carcinogenic risks for the exposure of NO3−, F−, Pb, and Cr elements. However, the heavy metal pollution and ecological risks are low. Based on the study's findings, the estimates will support initiatives and activities at the local, regional, and national levels, as nations like India need basin-level studies. It is also recommended to consider depth-wise geochemical and temporal chemical variation for further improved studies towards risk assessment. © 2024
Modeling Long-term Groundwater Levels By Exploring Deep Bidirectional Long Short-Term Memory using Hydro-climatic Data
(Springer Science and Business Media B.V., 2021) Sangita Dey; Arabin Kumar Dey; Rajesh Kumar Mall
Inevitable issues concerning the sustainability of groundwater resources are crucial under the present climatic situation. Therefore, the prevision of groundwater environments may able to reinforce the management system. In this respect present study considered a new method to predict long-term groundwater level framework as an alternative option of expensive physical models. The proposed Bidirectional Long Short-Term Memory (BLSTM) model can efficiently capture Spatio-temporal features from historical data. A highway LSTM network is also introduced within the architecture of the model to optimize the analysis. The relative performance of the proposed BLSTM with the highway LSTM (BHLSTM) network compared with simple BLSTM. Stack size increment of the BHLSTM and BLSTM layers can enhance the learning ability and improve by incorporating straight LSTM at the top of the architecture. The proposed model was applied to predict the groundwater level exemplary of the Varuna River basin for twenty years. The model incorporates the historical annual average of total precipitation, temperature, relative humidity, actual evapotranspiration, and groundwater level data to develop and validate the models. The result shows that the signals are captured reasonably well by a stack of four BHLSTM and straight LSTM models in forecasting groundwater levels. The predicted water level range (0—20 mbgl) has four categories low, medium, high, and very high which eventually, illustrates the water-threatened situation in upcoming years in the study area. It is also recommended to exploring this proposed method for further improvements and extensions towards interpreting spatial features. © 2021, The Author(s), under exclusive licence to Springer Nature B.V.
Physical exercise as a novel antidepressant agent: Possible role of serotonin receptor subtypes
(1994) Sangita Dey
Long-term exercise is associated with an antidepressant effect in patients with mild to moderate forms of nonbipolar depression and appears to be a promising new approach to its treatment. Adaptive changes in serotonin (5-HT) receptor functioning appears to play an important role in mediating the action of various antidepressant treatments. We investigated the adaptive changes in behavioral sensitivity of the 5-HT receptor subtype following 4 weeks of swimming exercise in normal rats, as well as in an animal model of depression (3 week, variety of chronic stressors). 5-HT1A autoreceptor sensitivity was assessed by hyperphagic response induced by 8-OH-DPAT (0.25 mg/kg, IP); 5-HT1A postsynaptic receptor by 5-HT syndrome induced by 8-OH-DPAT (0.75 mg/kg, IP), and 5 Me-ODMT (5 mg/kg, IP); and 5-HT2 receptor by wet dog shakes response induced by quipazine (1 mg/kg, IP) and 5MeODMT (5 mg/kg, IP). It was observed that exercise training in normal rats resulted in enhanced sensitivity of the 5-HT2 receptors along with subsensitivity of 5-HT1A autoreceptors. Exercise, given prophylactically along with chronic stressors, was able to prevent the development of behavioral deficit in the open-field test, and the animals developed remarkably enhanced sensitivity of 5-HT2 receptors. This adaptive supersensitivity of 5-HT2 receptor is also seen after various antidepressant treatments and may play an important role in mediating the antidepressant action of exercise. © 1994.
Potential impact of rainfall variability on groundwater resources: a case study in Uttar Pradesh, India
(Springer, 2020) Sangita Dey; Diva Bhatt; Saidul Haq; Rajesh Kumar Mall
Groundwater systems are largely influenced by rainfall variability which is considered the principal source of recharge. The present study explores the relation between the long-term rainfall (1992–2014) and the corresponding water table variation over the Varanasi district. The temporal trends of both the water table and long-term rainfall were analyzed using non-parametric Mann-Kendall time-series trend test. The district experienced an annual rainfall average of 876 mm during the study period. In the recent decade (2003–2014), the amount of annual rainfall and rainy days declined by 42 mm and 8 days, respectively, were compared with previous decade (1992–2002). The water table fluctuation had also shown decreasing trend in the recent decade and were compared with the previous decade. The frequent fluctuations in rainfall anomaly and water table fluctuation had been related to El Nino and La Nina events to study the impact of these events at regional scale. The intense cultivation of water intensive crops as well as rainfall variation was found to be one of the major causes behind the water table fluctuation in the study area. Therefore, artificial water recharge and change in cropping pattern through cultivating less water consuming crops with efficient irrigation technologies of water management may help to overcome the upcoming adverse situations. © 2020, Saudi Society for Geosciences.