The Change Trends Of Surface Water Quality Of Kun Shan

Water is one kind of natural resources which is necessary for human survival. In order to know the condition of surface water quality of Kun Shan, control the water pollution and ensure the security of water quality, this paper monitor and assess the surface water quality of Run Shan from 2003 to 2012, and analyze the causes of pollution. In this work,34 cross-section distribution sampling from centralized drinking water source (The second water plants of Miaojing River), seven rivers and three lakes, and getting the data of water quality factors by laboratory analysis, then using the single factor index method and comprehensive index method to assess the degree of water pollution, showing the main pollution factor by share rate, and finally proposing the strategies of pollution control. The main results as follows:(1) The affect of water preservation conditions on quality test results was reflected by changing the water sample preservation condition of permanganate index (CODMn), ammonia nitrogen (NH3-N) and total phosphorus (TP). The results showed that there is a certain influence on the test results when the non-national standard preservation condition was used. And with longer preservation time, the greater interference was appeared.(2) The dissolved oxygen (DO)> 5 days biochemical oxygen demand (BOD5), NH3-N, TP, fecal coliform (FC) in drinking water source can achieve Ⅱ water quality standards. CODMn can achieve Ⅲ water quality standards between 2003 to 2010, and reached Ⅱ water quality standards during 2011 to 2012. Total nitrogen (TN) attained Ⅲ water quality standards basically. Water quality is good during 2005 to 2007, is in low pollution status during 2008 to 2011, and later restored clean. The main pollution factor was CODMn-(3) In recent years, the pollution degree of Loujiang, Zhang Jiagang, Miaojing River, Wusongjiang, Jishuigang, Yanglintang, Qiputang was reduced basically. The water quality of Miaojing River can meet to functional requirements-Ⅲwater quality standards. The water quality of Loujiang and Zhangjiagang reached Ⅳ water quality standards. The quality parameters of other rivers reach Ⅳ water quality standards just after 2010. The main pollution factor of river was NH3-N.(4) Basically, the comprehensive index of Kuilei Lake and East of Yangcheng Lake decreased from 2007 to 2012, which decreased from 2005 to 2012 in Dianshan Lake. The water quality was in low pollution status in Kuilei Lake after 2008. the water quality factor can reach Ⅲ water quality standards basically after 2009 and the share rate of TN is the biggest. The TN and TP of the East of Yangcheng Lake and Dianshan Lake were over standards, especially the Dianshan Lake, which is much more serious. The other water quality factor can satisfy to functional requirements-Ⅲwater quality standards. The main pollution factor of lake was TP and TN.(5)The reasons of water pollution: ①The reasons of centralized drinking water source water pollution are the state’s policy to expand domestic demand after the financial crisis of 2008; ②The main river water pollution has something to do with upstream runoff, domestic wastewater, agricultural pollution and industrial waste water; ③In addition to above, the reason of water quality pollution of lakes is barrier net aquiculture.