Browsing by Author "Kshetrimayum, Krishnakanta Singh"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Distribution of rare earth elements and stable isotopic constituents along the groundwater flow paths in the Quaternary deposits of Imphal valley in north-east India
    (John Wiley and Sons Ltd, 2021-09-22T00:00:00) Singh, Laishram Premananda; Kshetrimayum, Krishnakanta Singh
    Groundwater samples collected from three flow paths (the western, central, and eastern flows) in the shallow aquifers of the Imphal valley of north-east India were examined to study the variation in hydrochemical and rare earth element (REE) characteristics along these flow paths. Each flow path covers a length of around 45 km towards the down gradient. In the western flow, the hydrochemical facies evolved from Na-Cl-Ca to Ca-Na-Mg-Cl-HCO3; in the central flow, it varies from Ca-Mg-Na-Cl to Na-Ca-Cl-HCO3 and in the eastern flow, it changes from Na-Cl to Ca-Mg-HCO3 indicating the evolution of saline water type in the piedmont zone to fresh water type towards the discharge zones around the Loktak Lake. The REE concentration varies along the flow path as the total light REE (LREE) is more enriched than total heavy REE (HREE) in the western and central flows, while LREE is less than HREE in the eastern flow. North American Shale Composite (NASC)-normalized REE patterns in these flow types show significant convex-up NASC-normalized patterns with depleted LREEs. The redox condition in the flow paths is controlled by redox-sensitive elements such as Eh, pH, Fe, Mn, U, Er, Gd, and Nd which vary relatively along with these flows. REE fractionation depicted by (Er/Nd)SN ratios are high around the upgradient and decrease along the down gradient towards Loktak Lake. The isotopic constituents (?18O and ?D) exhibit fluctuations in their ratios along the groundwater flow paths. The residual hill and piedmont zones are characterized by depleted isotopic composition while the alluvial and flood plains show enriched isotopic composition. Thus, the present study elucidates the behavioural change in major hydrochemical parameters including REE and isotopic constituents, along with the groundwater flow, which will provide a holistic view in understanding the evolution of groundwater in terms of its quality, quantity, and origin in the study area. � 2021 John Wiley & Sons Ltd.
  • No Thumbnail Available
    Item
    Quality assessment of surface water and groundwater giving emphasis on water quality index and irrigational indicators in the southeastern part of Manipur Valley, north-east India
    (John Wiley and Sons Ltd, 2021-12-21T00:00:00) Thokchom, Laxmi; Kshetrimayum, Krishnakanta Singh
    Water quality index (WQI) and irrigational indices for surface water and groundwater in the southeastern part of Manipur Valley in north-east India has been examined. The water samples were collected during the pre-monsoon season in the year 2016. Geologically, the Manipur Valley occurs as an intermontane piedmont-alluvial plain filled with Quaternary alluvium of fluvio-lacustrine origin. The basic chemical parameters of pH, total dissolved solids, electrical conductivity, total hardness, Cl?, HCO3?, Na+, Ca2+, Mg2+, Fe, Mn, and Zn were considered for computing water quality index for drinking water. Irrigational indices such as sodium absorption ratio, sodium percentage, Kelly's index, magnesium hazard, and residual sodium carbonate were calculated for determining the suitability for irrigational use. WQI, SAR, %Na+, KI, MH, RSC suggest that majority of the water samples are suitable for drinking and irrigational uses. They exhibit positive relations among them suggesting that these parameters are dependent over one another. About 20% of the piedmont zone groundwater are unsuitable for both drinking and agricultural purposes. The encrustation of gypsum, halite, and evaporite into the Disang shales enhances the dissolution process of ions such as Cl?, Na+, Ca2+, Mg2+ in the piedmont water leading to quality deterioration. Gibb's plots suggest that the chemical origin of water dominates with rock-weathering process, while hydrochemical facies evolved from the initial stage to intermediate stage. Therefore, proper integrated management and development of water resources is necessary for the effective utilization water resources particularly around the piedmont zone. � 2021 John Wiley & Sons Ltd.