Elucidating the Pollution Sources and Groundwater Evolution in Typical Seawater Intrusion Areas Using Hydrochemical and Environmental Stable Isotope Technique: A Case Study for Shandong Province, China

Abstract Seawater intrusion has a serious impact on industry, agriculture, and people’s daily life. Thus, the present study was designed to elucidate pollution sources groundwater evolution in typical areas of Shandong Province by hydrochemistry environmental isotope techniques. The water samples were collected analyze under different intrusion, south Laizhou Bay from 2005 2019. findings indicated that level dropping funnel caused overexploitation direct causation seawater three intruded areas. paths demonstrated had fastest rate highest degree evolution, followed Dagu River Basin. extent fitting mixing lines Bay, Longkou, Basin dominated palaeosaltwater modern sea-saltwater mixed respectively. Palaeosaltwater produces more severe salinization effect compared mixing. Meanwhile, isotopes are gradually enriched with deepening while decrease is delayed saltwater retreat. This stable aquiclude due chemical permeation will be released into aquifer after salinity attenuates aquifer. anthropogenic activities promoted fluorine nitrate Longkou most serious, high-density agricultural domestic activity.