<p>Mining activities are not only sources of potentially toxic element (PTE) pollution, but are also closely associated with natural radioisotopes. This study combined uranium radioisotopes to better understand the behavior of mine-derived PTEs in lake sediments. We collected surface sediments near an abandoned mine in Lake Daecheong, South Korea, and determined the concentration distribution of PTEs (Pb, Zn, Cu, Cr, Ni, As, Cd, and Hg) and uranium radioisotopes (²³⁵U and ²³⁸U) using an inductively coupled plasma mass spectrometer and a gamma spectrometer, respectively. The mean Zn, Cu, Ni, and Cd concentrations in the tributary near the mine were significantly higher than those of other PTEs, and their distributions tended to decrease downstream. The mean concentrations and distributions of ²³⁵U and ²³⁸U showed a consistent trend similar to that of PTEs. PTE pollution was extremely high only in sites downstream of the tributary directly affected by the mine. Zn, Cu, Ni, Cd, ²³⁵U, and ²³⁸U were closely related and were the most important factors controlling PTE origin. Consequently, the surface sediments were dominated by mine-derived PTEs (Zn, Cu, Ni, and Cd), suggesting a close relationship between the locations and PTE concentrations, highlighting mines as sources. Moreover, uranium radioisotopes were highly correlated with mine-derived PTEs, which will help improve our understanding of PTE behavior. Therefore, uranium radioisotopes can be used as tracers to assess the origin of PTEs from mining activities.</p>