@Article{Zhao_etal2017,
author="Zhao, Q.
and Su, X.
and Kang, B.
and Zhang, Y.
and Wu, X.
and Liu, M.",
title="A hydrogeochemistry and multi-isotope (Sr, O, H, and C) study of groundwater salinity origin and hydrogeochemcial processes in the shallow confined aquifer of northern Yangtze River downstream coastal plain, China",
journal="Applied Geochemistry",
year="2017",
volume="86",
pages="49--58",
optkeywords="Coastal confined groundwater",
optkeywords="Salinity",
optkeywords="Hydrogeochemcial processes",
optkeywords="Multiple environmental tracers",
abstract="Economically developed coastal areas have a high water demand, and their groundwater resources can be threatened by salinization. Many methods and tracers have been used to discriminate the source of salinization because a single method does not yield reliable results. In this paper, the shallow confined coastal plain aquifer, north of the downstream Yangtze River in China, is used as a case study to investigate the origin of the salinity and the relevant geochemical processes for this aquifer. Multiple environmental tracers of major ions, minor ions (Br-, I-), and isotopes (18O, 2H, 13C, 87Sr, 3H, 14C) were used so as to provide reliable conclusions. The TDS distribution of the aquifer has an increasing trend, from below 500~mg/L in the inland areas to more than 20,000~mg/L around the southeast coastline. The water chemical type evolves from HCO3-Ca to Cl-Na as the TDS increases. The results suggest that the groundwater salinity is influenced by seawater intrusion. The seawater proportions in the groundwater samples range from 0.07\% to 94.41\% and show the same spatial distribution pattern as TDS. The 3H and 14C values show that the highest salinity was mainly caused by a seawater transgression around 6000a B.P. The aquifer is also affected by other hydrogeochemical processes: base exchange has enriched Ca2+ and depleted K+ and Na+, sulfate reduction has reduced the concentration of SO42- and enriched HCO3-, and iodine-rich organic matter decomposition has enriched the concentration of I-. The iodine enrichment also suggests paleo-seawater intrusion. In addition, the precipitation of carbonate minerals has decreased the concentration of Ca2+, Mg2+, and HCO3-, albeit to a limited extent.",
optnote="exported from refbase (http://www.uhydro.de/refbase/show.php?record=182), last updated on Sat, 20 Jun 2020 10:41:02 +0200",
issn="0883-2927",
doi="https://doi.org/10.1016/j.apgeochem.2017.09.015",
opturl="http://www.sciencedirect.com/science/article/pii/S0883292717302925"
}