Traceability of Nitrogen and Oxygen Isotopes in Nitrates with the SIAR Model: Case Study on the Wangbeng Interval of the Huaihe River Basin
Xin Gu 3
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School of Earth and Environment, Anhui University of Science and Technology, Huainan, China
Environmental Protection Monitoring Station of Huainan city, Huainan, China
Jiangsu Geological Prospecting Team Three, Changzhou, Jiangsu, China
Liangmin Gao   

School of Earth and Environment, Anhui University of Science and Technology, China
Submission date: 2021-09-24
Final revision date: 2021-11-21
Acceptance date: 2021-12-05
Online publication date: 2022-03-23
Publication date: 2022-04-06
Pol. J. Environ. Stud. 2022;31(3):2255–2263
The identification of non-point nitrate sources is important for the study and management of non-point pollution sources in agricultural areas. In this study, the nitrogen and oxygen dual-isotope technique and the Stable Isotope Analysis in R (SIAR) model were used to qualitatively and quantitatively analyze nitrate sources in the Huaihe River basin in China. The results showed that the inorganic nitrogen in the water was mainly in the form of nitrate nitrogen with a mean concentration of 1.32 mg/L. In the middle section, the major pollution sources were manure and domestic sewage (43.46%) and soil (30.23%), followed by chemical fertilizer (14.56%), dead branches and fallen leaves (8.18%), and atmospheric deposition (3.55%). Chemical fertilizers due to farmland cultivation were a bigger pollution source in the upper reaches (28.73%) than in the middle reaches (5.76%) and downstream (4.37%). Chemical fertilizers (74.86%) were the main pollution source on the south bank, while soil (34.43%), manure and domestic sewage (33.24%), and chemical fertilizers (29.31%) were the main pollution sources on the north bank. The main sources of NO3- were soil, chemical fertilizer, excrement and domestic sewage. Atmospheric deposition and dead leaves were the secondary sources of nitrate pollution. Major pollution sources comprised a large proportion of the total pollution (89.67%) compared to secondary pollution sources (10.33%). These findings highlight the significant impacts of manure, domestic sewage, and agricultural fertilizer, and they can be used to support nitrogen management practices in agricultural areas.