A Study On The Dahekou Reservoir Nitrogen Pollution Characteristics And Source Apportionment By Isotope Technology

Our country is more deficient in water resource,and natural lakes and artificial reservoirs play an important role in social and economic development.In recent several decades,with the explosive increase population and high-speed development of economy,surface water pollution is increasingly serious,especially in lakes and reservoirs.The subjects are the Dahekou reservoir and its surroundings'water quality in sand source areas and cold areas,though samples collecting and measuring nitrate nitrogen,ammonium nitrogen,total nitrogen,nitrite,COD,and ?15N-NO3??18O-NO3 and other basic physicochemical indexes,applying SPSS and Arcgis software to analyze nitrogen pollution characteristics in different areas,and analyze the source of nitrogen pollution in the Dahekou reservoir,the major finding as follow.(1)Apply traditional hydro chemistry method to analyze nitrogen pollution characteristics with reservoir and its surrounding's water.The drought period's main pollution in reservoir is NO3-N,the highest concentration can get to 1.605mg/L,while the normal period and wet season's main pollution is TN,the highest concentration is 14.102mg/L,10.52mg/L respectively.Due to agricultural non-point's pollution,the highest concentration of NH3-N in river way in wet season,the maximum arrives at 1.63mg/L.(2)By layout sampling points to estimate their rate of contribution with the river amount into reservoir and atmosphere dust fall of quantity,make the first progress of main pollution source of the reservoir.In the whole 2016 the Big River Mouth Reservoir's pollution load capacity mainly from the river flowing substance,which can get to 21.05t,occupies 72.3 percent in the whole pollution load capacity,while the atmosphere dust fall does 27.7 percent.The result shows that the river falling substance is the main reason of nitrogen pollution.(3)Apply the stable isotope technology to analyze the reasons of pollution,the result shows that in normal and drought the value of period 75 percent samples?15N-NO3 and?18O-NO3 of domestic sewage and livestock's faeces are in normal range,while in wet period the chemical fertilizers and livestock's faeces are the main reason for pollution.(4)Analyzing the nitrogen pollution characteristics,the spring,autumn,winter,the values of?15N-TN are in sand land,farming land range,which occupy more than 40 percent in total samples.It shows that sand land and farming land are the main reasons for falling dust,while in the summer the farming land are used reasonably.