The Contribution of Nitrate Sources in Liao Rivers, China, Based on Isotopic Fractionation and Bayesian Mixing Model

The riverine nitrate stable isotopic compositions characterize its fate and reflectits sources. In this study, the proportional contribution of riverine nitrate was calculated by Bayesian mixing model based on the dual nitrate isotopes in Liao Rivers, Northeast of China after considering the isotopic fractionation of nitrogen transformation. The results show the contribution of nitrogen sources haslarge variations in different section of rivers. The proportional contribution from synthetic fertilizer increases after considering impacting for isotopic compositions of nitrate by the key processes at the high flow season. Thus, the main transformations and isotopic fractionations should be identify when calculate the contribution of sources accurate using the Bayesian model.