Kalman Filter-Spectrophotometry Simultaneously Analyze Trace Cu²⁺, Cd²⁺, Zn²⁺ And Pb²⁺ In Surface Water From Three-Gorge Valley In Chongqing City

The Three Gorges Project on the Yangtze River is the biggest hydropower project in the world. The project would benefit the river transportion, flood control and hydropower. However, after the construction of the Three Gorges Reservoir, great change of the flow and quality of water will happen in Changjiang segement of Three Gorges Reservior area. Especially, with the development of economy in Three Gorges Reservoir area, there is an increasing trend in discharge of pollutants, greatly affecting the water quality environment. For example, greater river width and depth, decreased water flow velocity, etc. These would lower the potential for pollutants solubility and dissolved oxygen recovery of the Three Gorges Reservior water body and thus its self-purification capactity. Then, distribution and behavior of heavy metal pollutants in water body be also changed distinctly. The heavy metal ion is hard to be decompounded by environment, and it is easy to be taken into food chain by plant and animal. Eventually, it will be concentrated in the human body and affect human health enormously. So it is essential to research a set of determination method of heavy metal ion to understand the water quality of Three Gorge Valley.The time of researching simultaneous spectrophotometric determination is a short time. Because of its benefit, it has a superiorly developing and practicing value. Speaking of water quality of Three Gorge Valley, it is exigent to intensify the water quality monitor and speed up modernization of determination system. Without enough modern determination instrument and advanced message management system, we can not understand the water quality instantly and precisely. And it is hard to control pollutant reasonably and promptly. If we want to control water pollution effectively and logically, to construct a water determination system is the first step. And using a rational simultaneous spectrophotometric determination method is a development orientation of environment determination. Not only we can understand the distribution of heavy metal ion veraciously to control the pollutant elimination, but also we can improve the determination speed, shorten the determination time, economize a lot of manpower, material resources and financing. Eventually, we can provid credible data to sustain ecological environment Sustainable development in Three Gorge Valley and keep harmonious between human and nature.2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol is one of high sensitive color reagents to determine the concentration of trace metal ion, and Kalman Filter algorism is an effective iterative computing method that could directly resolve each single component information from some mixed responsive information. Using 2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol as chelating color reagent,chloroform as for extracting reagent, Cu²⁺,Cd²⁺,Zn²⁺ and Pb²⁺ trace metal ions were measured simultaneously from mixed responsive signals from the chelate containing the four ions under almost same reaction condition. The absorbency of the reaction system Cu-Zn-Pb-Cd-(5-Br-PADAP) were analyzed in same spectral range from 550 nm to 565 nm at interval of 0.05 nm because of the serious overlapping absorption character. The four trace metal ions namely Cu²⁺,Cd²⁺,Zn²⁺ and Pb²⁺ in water samples prepared in laboratory and surface water samples along the Yangtse and Jialing river have been simultaneously determined by Kalman Filter and spectrophotometric analysis. The determinating results showed that recovery of the method is between 91.9﹪-113.1﹪to samples of laboratory. The Kalman filtering analysis result compared with the corresponding pollution data from governmental water quality monitoring sites has also shown a reasonable consistency and reliability so that the method could be directly used for monitoring simultaneously real samples containing multi heavy metal ions in various surface water of rivers quantificationally, and especially to the local monitoring of real water system.