琼江支流蟠龙河水质状况及高时间分辨率下典型月份水质趋势分析OACSTPCD

The issue of water environment is related to human and ecological security.In recent years,the phenomenon of eutrophication and water bloom in some rivers have caused concerns.In this paper,the Panlong River,a tributary of the Qiongjiang River in Sichuan,was taken as a research area;the single factor evaluation method,improved Nemerow pollution index method,and principal component analysis method were used to analyze the water quality of the Panlong River since the 14 th Five-Year Plan;and algae data and synchronous water quality monitoring data were used to analyze typical monthly water quality trends under high time resolution.The results indicated:the overall water quality of the Panlong River was good in 2021 and 2022,but nitrogen and phosphorus had the greatest impact on the water quality.In April 2022,cyanobacteria bloom appeared,and the water quality of Yuanbazi in the upstream section was seriously affected.Algae density(Ad),chlorophyll a(chla),chemical oxygen demand(CODCr)and total phosphorus(TP)showed a strong positive correlation.In December 2022,the water quality of Paomatan in the middle reaches was severely affected,and was more likely to be affected by the release of endogenous pollutions such as algal decay.The research indicated:the current factors restricting further improvement of the water quality in the Panlong River has shifted from the point source pollution and the non-point source pollution to water ecological issues caused by eutrophication of algae blooms in the river.The main reasons for the formation of water blooms are the combined effects of multiple factors such as increased nitrogen and phosphorus,insufficient runoff,high temperature and low rainfall.The current water quality of the Panlong River is more likely to be affected by the growth cycle of algae,and the water environment in different river sections varies significantly.Therefore,the watershed management needs to be more specific.