National-scale investigation of dual nitrate isotopes and chloride ion in South Korea: Nitrate source apportionment for stream water.

Nitrate sources in surface water have been identified using dual-isotope compositions of nitrate with various tools to efficiently manage the water quality at the local scale. Correlation between Cl and NO has also been used to identify NO. In this study, we assess the reliability of the dual-isotope approach and Cl in terms of nitrate source apportionment.

Temporal variation in riverine organic carbon concentrations and fluxes in two contrasting estuary systems: Geum and Seomjin, South Korea.

In this study, surface water samples were collected at sites located in the lowest reaches of closed (Geum) (i.e. with an estuary dam at the river mouth) and open (Seomjin) estuary systems between May 2016 and May 2018.

Anthropogenic rare earth elements and their spatial distributions in the Han River, South Korea.

Rare earth elements (REE) consist of lanthanides (from La to Lu), together with yttrium and scandium, in which anthropogenic REE, such as gadolinium (Gd), lanthanum (La), and samarium (Sm), has emerged as micro-contaminants in natural waters in highly developed countries. Here, we collected water samples in the Han River (HR) and its tributaries flowing through Seoul Capital Area, the world's second largest metropolitan area in order to examine how and to what extent anthropogenic REE anomalies may occur. Water samples show higher light REE concentrations than heavy REE concentrations, while wastewater treatment plant (WWTP) samples display much higher heavy REE concentrations due to high Gd concentration.