Study On The Characteristics Of Water Cycle And Nitrogen Pollution In Hun River And Taizi River Basin By Using Stable Isotope And Hydro Chemical Data

To assess the distribution of different forms of nitrogen and identify the nitratepotential sources, surface and ground water samples in Hun River and Taizi RiverBasin, China, were collected at September2012for analyzing the characteristics ofhydrochemistry and environmental isotope. In this paper, the primary means werefield sampling and laboratory experiments. The Groundwater Environmental QualityComprehensive Evaluation Method was also be used to evaluate the studied rivers,and the main evaluation factors were NO3--N, NO2--N, and NH4+-N.Results show that the main form of nitrogen in surface and ground water of HunRiver is NO3--N. The concentration of NO3--N in surface water was an increasingtrend as the river, the highest concentration was6.13mg/L. NO2--N and NH4+-N wereat low levels and can not be detected in upstream areas. The concentration of NO2--Nvaried from0to0.07mg/L, with an average of0.03mg/L. While the concentration ofNH4+-N was in the range of0~3.97mg/L, with an average of1.41mg/L. The densityof NO3--N(0.62~23.47mg/L) in groundwater was higher than surface water, and withan average of9.87mg/L. There were more than1/3groundwater samples detectedNO2--N, with a lower average concentration (0.014mg/L).NO3--N occupied he maximum total nitrogen (TN) content in Taizi River,NO3--N pollution was serious in the groundwater that the average concentration ofNO3--N was20.26mg/L. NO2--N varied from0~0.93mg/L, surface water in thedownstream had the poor pollution of NH4+-N, the maximum value reached12.07mg/L.The results of Groundwater evironmental quality evaluation showed: the qualityof groundwater environment in Hun River Basin was good in totally, and reached thethird class refered water quality standards. In the upstream of Hun River, the qualityof groundwater environment was better, but due to the human impacts, the NO3--Ncontents of G2sampling point increased. In Shenyang and Fushun, industrial wastewater and domestic sewage discharged disorderly, then made the groundwaterheavily-polluted. The content of NO2--N sharply increased, lesding to very poorgroundwater quality. The groundwater quality in Taizi River Basin was poor ingeneral. The contents of NO3--N and NO2--N were generally high with the influenceof human activities, and the spatial and temporal differences was great. The groundwater in Hun River and Taizi River Basin had great concentrations ofCl-and NO3-. In front of the intersection of two rivers, there were two groundwatersampling sites located in irrigation districts. The showed abnormal increased of Cl-concentration. Flood irrigation and intensification of agricultural facilities withexcessive chemical fertilizers, caused the increase of Cl-concentration in shallowgroundwater and the pollution of NO3-.According to the relationship between NO3-and Cl-and the results of nitrogenisotope, nitrogen pollution of surface water in Hun River Basin was characterized byhuman and animal feces and sewage. The value of δ15N in the groundwater is greaterthan neighboring surface water, the nitrogen pollution in groundwater was influencedby the surface water in upstream. NO3--N in groundwater was mainly from soilorganic nitrogen in downstream.The value of δ15N in the surface water of Taizi River concentrated in6‰~15‰,and the concentration of NO3--N was not high. Nitrogen pollution of surface watercame from organic nitrogen and inorganic fertilizers. Groundwater was affected byhuman activities in a long term, the characteristics of nitrogen isotope valuesperformance derived from human and animal feces.