深圳沿海带浅层地下水的稳定同位素与地球化学

Hydrogeochemistry and stable isotopes of shallow groundwater in coastal Shenzhen

在深圳沿海带取64件浅层地下水样品,作常规离子水化学和氢氧稳定同位素测试,来识别深圳沿海带海水入侵程度。采用主要离子比值-Cl、Br/Cl比值和piper三线图等水文地球化学方法以及氢氧稳定同位素δD-δ18O、δ18O-Cl结合分析水样数据。分析发现Cl-<300mg/L的样品均来源于降水入渗补给,没有海水混入;300mg/L<Cl-<885mg/L之间无样品;Cl->885mg/L的12件样品均有海水混合,系降水(淡水)和海水的混合水。

Hydrochemical composition of major ions and stable isotopic values of hydrogen and oxygen of 64 shallow groundwater samples in coastal Shenzhen were tested to determine the extent of seawater intrusion.A combination of hydrogeochemistry（major ions /Cl versus Cl,Br /Cl ratio and piper diagram） and stable isotopes methods（δD-δ18 O relation,δ18 O-Cl plot） were used to analysis the data of samples.The study indicate that 52 samples with salinities lower than 300mg /L Cl-recharged by atmospheric precipitation.12 samples with concentration of chloride higher than 885mg /L were mixing water of fresh water and seawater.And the relationships between major ions /Cl and Cl show a discontinuity in the chloride concentration range between 300 and 885mg /L.