Pollutant Fluxes Of Inflow And Outflow Rivers And Assessment On Water Environment Carrying Capacity Of Lake Taihu

Water environment stress has been increasing in Taihu Lake Watershed due to the rapid economic development and population growth.First of all,the total nitrogen and phosphorus pollutant fluxes of inflow and outflow rivers of Lake Taihu were analyzed based on the data from the years 2001 to 2010.Secondly,the water quantity of inflow and outflow rivers of Lake Taihu kept in balance from the years 2007 to 2010;The rules of pollutant fluxes were different,intcluding total nitrogen and total phosphorus.Furthermore,we applied the water environmental carrying rate(WECR)to assess the the excess of water environmental carrying capacity(WECC)or the extent of coordination of environment and economics which can be recognized.We expected to support the constructive suggestions to regulate the Taihu.The results showed as follows:(1)The rules for every month were different between the total nitrogen and phosphorus pollutants(2001-2010).The results showed that the total nitrogen was steady for ten years,which rose from January to March and then fell down gradually.The concentration in spring and summer was higher than that in autumn and winter.The maximum of every year was in March,April and May and the minimum was in August,September,October and November.For the total phosphorus pollutants,it showed a wave up and down.The results were mainly due to both the internal and external loadings of nitrogen and phosphorus pollutants to the lake with the season changes.Recent research results were expected to figure out the constructive suggestions and prospected solutions for the eutrophication and management of Taihu Lake Watershed.(2)the water quantity of inflow and outflow rivers of Lake Taihu kept in balance from the years 2007 to 2010;At the same time,it was changing with the season;The rules of pollutant fluxes were mostly similar,including total nitrogen and total phosphorus;For the fluxes of the total nitrogen and total phosphorus,it was higher from March to September than that from October to December,January to February.(3)The rules of the allowable water environmental capacity and the remaining water environmental capacity were different,including the total nitrogen,the total phosphorus and the potassium permanganate index.In specific,the allowable water environmental capacity kept in balance.Meanwhile,the remaining water environmental capacity of total nitrogen and total phosphorus was less zero,and the potassium permanganate index was above zero.(4)There were different trends about the water environmental carrying rate(WECR),including the total nitrogen,phosphorus,the potassium permanganate index of salt and the ammonia nitrogen(2007-2010).Based on the balance of water,we introduced the WECR to assess the WECC.The results showed that the WECR of the total nitrogen and phosphorus was above 1,while the WECR of potassium permanganate index of salt was less than 1.Combined the results above,we made the strategies to regulate the nitrogen and phosphorus pollutants,promoted the management of keeping the ability of WECC and monitored the water quality of Taihu Lake Watershed.