Trace elements and dissolved organic matter data from Lake Sihwa

This dataset contains dissolved trace element and dissolved organic matter data collected from Lake Sihwa, Korea, and its surrounding streams in May 2024 and September 2025. It includes sampling locations and coordinates, and measurements of dissolved Mn, Fe, Zn, Ni, Cu, and Co; dissolved organic carbon (DOC); and the humic-like component of fluorescent dissolved organic matter (FDOMH). These data were collected to investigate the distribution and behavior of dissolved trace elements and organic matter across the freshwater–seawater mixing zone.