『Abstract
　The need for more agricultural or residential land has encouraged reclamation at the coastal areas of Korea since 1200 AD (approximately). The groundwaters of these reclaimed areas could be expected to reveal hydrogeochemical properties different from those of areas directly affected by seawater intrusion. The purpose of this study, therefore, was to examine the salinization of shallow groundwater in a coastal reclaimed area and to identify the effect of land reclamation on groundwater quality. Major cations and anions, iodide, total organic carbon, δD, δ¹⁸O and δ¹³C were measured to assist the hydrogeochemical analysis. Chloride, δD and δ¹⁸O data clearly show that the Na-Cl type water results from mixing of groundwater with seawater. In particular, the δD and δ¹⁸O of Ca+Mg-Cl+NO3 type groundwaters are close to the meteoric water line, but Na-Cl type waters enriched in chloride are ¹⁸O-enriched with respect to the meteoric water line. Meanwhile, carbon isotopic data and I/Cl ratios strongly suggest that there are various sources of salinity. The δ¹³C values of Na-Cl type groundwaters are generally similar to those of Ca+Mg-Cl+NO3 type waters, which are depleted in ¹³C with respect to seawater. I/Cl ratios of Na-Cl type groundwater are 10-100 times higher than that of seawater. Because the reclamation has incorporated a large amount of organic matter, it provides optimum conditions for the occurrence of redox processes in the groundwater system. Therefore, the salinization of groundwater in the study area seems to be controlled not only by saltwater intrusion but also by other effects, such as those caused by residual salts and organic matter in the reclaimed sediments.

Keywords: Groundwater; Reclaimed area; Seawater intrusion; Salinization; Redox processes』

Introduction
Methods
Results and discussions
　Hydrogeochemistry
　Environmental isotopes
　Iodide properties
Conclusions
Acknowledgements
References

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