Abstract: Accurately identifying the sources of agricultural NPS pollution is the premise to control pollution and to carry out environmental protection policies. By comparing the δ¹⁵N values of potential pollution sources and water samples, we can easily and directly figure out the sources based on the different δ¹⁵N values. Qualitative identification of NPS pollution and quantitative calculation on contribution rate by using δ¹⁵N values have been done by researchers in China and abroad. In this paper, the fundamental principles of using this isotopic tracer to identify the NPS pollution sources is briefly introduced. The research progress in this regard is highlighted, present limitations and future prospects of this method are also presented.

Key words: agricultural non-point source pollution, identification of pollution sources, stable N isotope, pollution contribution rate