Research And Analysis Of Water Quality Security Assessment System In Meishan Section Of Minjiang River

Water is one of the most important resources for the existence of life on the Earth,however,various problems of water environment seriously affect the existence of human beings and the steady development of social economy.Minjiang River is an important tributary of the Yangtze River,and Minjiang River（Meishan section）is the middle reaches of the basin.The various waste and sewage produced in Meishan every year pose a great risk to the water environment of the Minjiang River,extremely easy to cause water pollution.In-depth evaluation and improvement of water quality in Minjiang River of Meishan section is an important problem to be solved.In recent years,there have been many water pollution accidents in China,the consequences of which are very serious,therefore,water safety has been paid more and more attention.Water quality safety assessment is an important aspect of water safety,this paper studies and evaluates the present situation of water quality safety in Meishan section of Minjiang River,and takes measures to reduce or eliminate the hidden danger of water quality safety in time,so as to prevent the adverse effects of water pollution on social economy and human health.In this paper,the Meishan section of the Minjiang River is taken as the research object,and the water quality of the Minjiang River from 2014 to 2019 is evaluated by using the comprehensive pollution index method.The results produced by the comprehensive pollution index method of each water quality monitoring section is more than 0.4,in addition,nitrogen and phosphorus are the key pollutants in the basin,the pollution level of the Minjiang River tributaries is higher than that of the main stream,and the Tiquan River,a tributary,is most seriously polluted.The most serious,it is mainly polluted by life,agriculture and industrial pollution sources.The eutrophication degree of water environment in Minjiang River was evaluated by TLI.The results showed that the whole of Minjiang River was in the state of light eutrophication and medium eutrophication,and the degree of eutrophication was the most serious in the tributary of Tiquan River.Based on the evaluation and analysis of the current water environment quality of the Meishan section of the Minjiang River,this paper further uses the Spearman rank correlation coefficient method to study the pollution trend of key water quality indicators in the basin.The results show that the dissolved oxygen,BOD₅,ammonia nitrogen,COD_Mnand TP in the main stream Minjiang River generally showed an improvement trend.The ammonia nitrogen,COD_Mn and TP in the tributaries of the Minjiang River generally showed an improvement trend.The overall change trend of other indicators was not obvious.Based on fuzzy comprehensive evaluation method,this paper evaluates the water quality safety of the Minjiang River（Meishan section）,combines the evaluation results of the water quality situation in Minjiang River,selects the evaluation indexes,and uses the principal component analysis method（PCA）to determine the weight of the indexes,based on this,a complete water quality safety assessment system for the Minjiang River（Meishan section）is constructed,and the water quality safety status of each section of the Minjiang River is determined.According to the assessment results of water quality safety in the Meishan section of the Minjiang River,the water quality safety situation in the main stream of the Minjiang River is generally good,and the water bodies in the tributaries of the Minjiang River are polluted to varying degrees,the comprehensive water pollution control measures adopted in Meishan have achieved significant improvements.