Extensive human activities have resulted in increased delivery of nitrogen to rivers and streams, which pose serious threats to aquatic ecosystems and human health. Hence, it is crucial to identify the sources and transformations of nitrate for water quality management. Coupled nitrogen and oxygen isotopes of nitrate have proven useful in identifying nitrate sources and transformation in rivers. However, isotopic fractionation and low-resolution monitoring limit the accurate estimation of nitrate dynamics.
Here, we conduct high-frequency sampling campaigns and isotopic analysis in the Xijiang River, and estimate the proportional contributions of multiple nitrate sources using the Bayesian isotope mixing model by incorporating isotopic fractionation. Finally, the interannual variations in nitrate flux were examined over the past 35 years at the mouth of the Xijiang River. This study combines hydrochemistry, stable isotopes with multi-statistical method, and make important progress in accurate estimation of nitrate dynamics in river.
Paper citation: Cai Li, Si-Liang Li*, Fu-Jun Yue, Jing Liu, Jun Zhong, Zhi-Feng Yan, Ruo-Chun Zhang, Zhong-Jun Wang, Sen Xu. 2019. Identification of sources and transformations of nitrate in the Xijiang River using nitrate isotopes and Bayesian model. Science of the Total Environment. 646, 801-810.
Full text link: https://www.sciencedirect.com/science/article/pii/S0048969718328407
