The hydrological and pollution processes are an important science problem for aquatic ecosystem. In this study, the samples of river water, reservoir water, shallow groundwater, deep groundwater, and precipitation in mining area are collected and analyzed. δD and δ18O are used to identify hydrological process. δ15N-NO3- and δ18O-NO3- are used to identify the sources and pollution process of NO3-. The results show that the various water bodies in Fenhe River Basin are slightly alkaline water. The ions in the water mainly come from rock weathering. The concentration of SO42- is high due to the impact of coal mining activity. Deep groundwater is significantly less affected by evaporation and human activity, which is recharged by archaic groundwater. There are recharge and discharge between reservoir water, river water, soil water, and shallow groundwater. NO3- is the main N species in the study area, and forty-six percent of NO3--N concentrations exceed the drinking water standard of China (NO3--N ≤ 10 mg/L content). Nitrification is the main forming process of NO3-. Denitrification is also found in river water of some river branches. The sources of NO3- are mainly controlled by land use type along the riverbank. NO3- of river water in the upper reaches are come from nitrogen in precipitation and soil organic N. River water in the lower reaches is polluted by a mixture of soil organic N and fertilizers.
Keywords: Hydrological processes; Isotope; Mining area; Pollution processes.
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