title: Geochemical and isotopic data for restricting seawater intrusion and groundwater circulation in a series of typical volcanic islands in the South China Sea.
abstract: The decline of groundwater table and deterioration of water quality related to seawater have long been regarded as a crucial problem in coastal regions. In this work, a hydrogeologic investigation using combined hydrochemical and isotopic approaches was conducted in the coastal region of the South China Sea near the Leizhou peninsular to provide primary insight into seawater intrusion and groundwater circulation. Hydrochemical and isotopic data show that local groundwater is subjected to anthropogenic activities and geochemical processes, such as evaporation, water-rock interaction, and ion exchange. However, seawater intrusion driven by the over-exploitation of groundwater and insufficient recharge is the predominant factor controlling groundwater salinization. Systematic and homologic isotopic characteristics of most samples suggest that groundwater in volcanic area is locally recharged and likely caused by modern precipitation. However, very depleted stable isotopes and extremely low tritium of groundwater in some isolated aquifers imply a dominant role of palaeowater.
authors: School of Earth Sciences and Engineering, Hohai University, Nanjing 210098, Jiangsu, PR China.
authors: Wenjie
authors: W
authors: Zhang
authors: State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, Jiangsu, PR China.
authors: Xi
authors: X
authors: Chen
authors: School of Earth Sciences and Engineering, Hohai University, Nanjing 210098, Jiangsu, PR China. Electronic address: tan815@sina.com.
authors: Hongbing
authors: H
authors: Tan
authors: School of Earth Sciences and Engineering, Hohai University, Nanjing 210098, Jiangsu, PR China.
authors: Yanfei
authors: Y
authors: Zhang
authors: Zhanjiang Branch Office of Guangdong Hydrological Bureau, Zhanjiang 524037, PR China.
authors: Jifu
authors: J
authors: Cao
mesh_terms: D002681:China; D004784:Environmental Monitoring; D060587:Groundwater / Q000737:chemistry*; D062312:Islands; D007554:Isotopes / Q000032:analysis; D054712:Salinity; D012623:Seawater / Q000032:analysis*; D060753:Water Quality; D062066:Water Resources
chemical_list: D007554:Isotopes
keywords: Groundwater salinization; Recharge and circulation; Seawater intrusion; The South China Sea