Research On Temporal And Spatial Variation Of Water Environmental Quality In Qiqihar Section Of The Nenjiang

Nenjiang is the longest tributary of the Heilongjiang River system and is closely related to the economy and development of Heilongjiang Province.Qiqihar is the political,economic,cultural and transportation center of the western region of Heilongjiang Province and one of the important industrial cities in Heilongjiang Province.At present,there are few related studies on water quality assessment and pollutant analysis in Nenjiang River.Therefore,it's crutial for the ecological and economic development of Nenjiang River Basin and Qiqihar to study on the changes of water environment quality in Nenjiang Qiqihar section,to analyze of major pollutants,and to propose water quality regulation strategy.This paper investigates the research status at home and abroad,and analyzes the proportion of pollutants in different types of sewage in Qihar City.It compares the characteristics of different water environment quality assessment methods,and selects gray correlation evaluation method and water quality comprehensive identification index method as evaluation methods.,DO,permanganate index,BOD₅,COD,ammonia nitrogen,total nitrogen,total phosphorus,copper,zinc,fluoride,fecal coliforms were selected as 11 evaluation indicators.The water environment quality of the three sections of Liuyuan,Jiangqiao and Laha in Ningjiang Qiqihar section from 2013 to 2017 was evaluated in dry season,flat water period,high water period and annual average.The spatial and temporal variation characteristics of the water quality category of Qiqihar section of Nenjiang River were analyzed,and the main pollution indicators were determined.The research results show that the water quality of the Qiqihar section of Nenjiang meets the planning requirements of the water function area.Comparing the evaluation results and processes of different methods,it is found that the grey correlation evaluation method is relatively complex and sensitive to water pollutants.It is suitable for evaluating water bodies with high evaluation accuracy.The water quality comprehensive index method is simple and inclusive,suitable for daily use.Evaluation of the quality of the water environment.The water quality was the worst in 2013,and the water quality improved from 2014 to 2017.For different water periods,the water quality during the flat water period is the best,followed by the dry season,and the water quality during the wet season is the worst.For the three monitoring sections,Liuyuan has the best water quality,followed by Jiangqiao,and Laha has the worst water quality.However,the overall compliance with the water environment functional area planning.The temporal and spatial variation characteristics of water quality pollutants in Qiqihar section of Nenjiang River were analyzed,and the main pollution indicators were dissolved oxygen,chemical oxygen demand,total nitrogen and fecal coliform.In response to major pollutants,the corresponding water environment quality control measures are proposed.