Submarine Groundwater Discharge from an Urban Estuary to Southeastern Bay of Bengal, India: Revealed by Trace Element Fl

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Submarine Groundwater Discharge from an Urban Estuary to Southeastern Bay of Bengal, India: Revealed by Trace Element Fluxes R. Prakash1,2 · K. Srinivasamoorthy1 · S. M. Sundarapandian3 · C. Nanthakumar4 · S. Gopinath5 · K. Saravanan6 · F. Vinnarasi1 Received: 17 April 2020 / Accepted: 10 October 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020

Abstract Submarine groundwater discharge and associated trace element fluxes from the Coleroon River estuary to south bay, India, has been attempted, because increasing trace elements could result in harmful algal blooms and eutrophication. Trace elements (Al, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Mo, Ba, Pb, Th, and U) in surface water, pore, and groundwater samples were monitored for 10 days in three locations (A, B, and C) by considering tidal fluctuations. The trace elements Al, Cr, Fe, Ni, Zn, Sr, Mo, Pb, Th, and U were greater and found to be influenced by processes, such as fresh groundwater discharge and seawater intrusion. Lower Mn, Cu, and Ba signifies impact due to sediment adsorption, mixing, and elemental exchange during fresh groundwater and seawater mixing. Salinity versus trace element plot infers greater trace element mobility with cumulative salinity influenced by the conformist behavior of freshwater, seawater, and mixing. The calculated submarine groundwater discharge supported dissolved trace elements fluxes were 107,047.8 n mol ­d−1 m−1 for location A, 183,520.2 n mol d−1 m−1 for location B, and 181,474.4 n mol d−1 m−1 for location C, respectively. Variations in dissolved trace elements fluxes are attributed to variations in pH, free redox environment in the aquifer, adsorption or desorption by sediments, and the environmental cycle of marine organisms. Abbreviations SGD Submarine groundwater discharge TE Trace element STE Subterranean estuary BGL Below ground level SW Surface water GW Groundwater * R. Prakash [email protected] 1



Department of Earth Sciences, Pondicherry University, Puducherry 605014, India

2



Department of Geology, Khajamalai Campus, Bharathidasan University, Trichy 620 023, India

3

Department of Ecology and Environmental Sciences, Pondicherry University, Puducherry 605014, India

4

Department of Statistics, Salem Sowdeswari College, Salem 636010, India

5

Institute of Geophysics, Universidad Nacional Autónoma de México, Mexico City, Mexico

6

Department of Civil Engineering, Indian Institute of Sciences, Bangalore 560 012, India



PW2 Pore water 60 cm PW4 Pore water 120 cm Al Aluminium Ba Barium Cr Chromium Cu Copper Fe Iron Mn Manganese Mo Molybdenum Pb Lead Sr Strontium Th Thorium U Uranium Zn Zinc FSGD Fresh SGD RSGD Recirculated SGD dTE Dissolved trace elements n mol d−1 m−1 Nano mol per day per meter mg L−1 Milli gram per litre km Kilo meter m Meter mm y−1 Milli meter per year °C Degree Celsius

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Vol.:(0123456789)



L min−1 Litre per minute μm Micro meter During recent decades, submarine groundwater discharge (SGD) has gained attention due to its crucial path