To explore the sources and transformation of surface water nitrate in Dagang River Basin,we defined eight sampling points from the upstream to downstream along the Dagang River from which samples of surface water and sediment were collected when precipitation occurred in autumn(November 2020)and spring(March 2021).A total of 20 samples of groundwater,sewage,manure and soils were analyzed with hydrogeochemistry,nitrogen and oxygen isotope tracer technology,and Bayesian mixture model.Results show that:(1)the total nitrogen(TN)concentration of surface water was 3.20mg/L in the autumn and 3.23mg/L in the spring(70.9％in the form of NO3-N),which was higher than the environmental quality of surface water V standard;(2)nitrogen cycling process in the Dagang River Basin was dominated by nitrification,while precipitation led to the seasonal changes in nitrate concentration;(3)domestic wastewater and livestock manure were two main sources of nitrate to the watershed waters,collectively contributing(40.8％±32.8％)in the autumn and(55.8％±27.3％)in the spring,followed by groundwater and soils,while the least by precipitation.
关键词
降水/大港河流域/氮氧双同位素/硝酸盐来源/贝叶斯混合模型/来源解析
Key words
rainfall/Dagang River Basin/nitrogen and oxygen isotopes/sources of nitrate/Bayesian mixture model/source identification
维普
万方数据