【Objective】In recent years, with the continuous intensification of human activities, groundwater nitrogen pollution has become a typical environmental problem worldwide. In order to identify nitrogen pollution sources, contribution ratio, migration and transformation characteristics of shallow groundwater, Fourteen surface water, Twenty Four shallow groundwater and Seven soil samples were collected from the main water supply area of Caidian District, Wuhan City, Hubei Province, their water chemical indexes, nitrogen isotopes, hydrogen and oxygen isotopes, etc. were tested and analyzed.【Methods】 Based on the local land use type, water chemistry and δ15N-NO3-、δ18O-NO3- double isotope tracer technology were integrated to identify the nitrate nitrogen pollution sources and their migration and transformation rules in groundwater in the study area, and the Iso-Source model was further used to quantitatively identify the contribution proportion of different nitrogen pollution sources.【Results】 The types of regional nitrogen pollution were mainly nitrate nitrogen, among which about 66.7% of the NO3- concentrations in groundwater sampling points exceeded the WHO limit (10mg/L), Nitrification of sewage and manure, soil organic matter and ammonia-containing fertilizers is the main sources of NO3-,, and the average contribution rates of nitrate nitrogen to shallow groundwater were 48.6%, 32.9% and 18.5%, respectively, which were affected by obvious human activities. Further combination of regional water chemistry and hydrogen-oxygen isotopic composition showed that the morphological transformation of regional surface water and groundwater nitrogen was mainly affected and controlled by nitrification. 【Conclusion】The research results will provide a theoretical basis for further understanding of nitrogen cycling process and nitrogen pollution control in Caidian District.
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