Indication of trace elements and isotopes in groundwater to seawater intrusion and groundwater origin: a case study at Bao'an district of Shenzhen city, Guangdong province

Shenzhen City is one of the most developed areas of China. However, it is also an area liable to be affected by seawater intrusion. In this study, 24 boreholes are constructed in the Bao' an district of Shenzhen City as the study area and 24 groundwater samples are collected from these boreholes. Furthermore, the contents of trace elements and the values of δD and δ18O in groundwater samples are determined to indicate the occurrence of seawater intrusion. The results show that some trace elements such as Br, B, Li, and Sr as well as δD and δ18O can be used to analyze the extent of seawater intrusion and to delineate the different sources of groundwater. This study can offer scientific guides for the protection of groundwater resources in Bao'an district. (authors)