Study On The Early Warning Index System Of Water Pollution Accidents For The Three Gorges Reservoir In Chongqing

Nowadays with the increasing development of economy and water resources being exploited and utilized,water environment faces the enormous pressure.The problem of water environment that troubles human survival and sustainable development of countries in the word has become the focus and difficulty.Many major water pollution accidents occurred in our country,not only cause enormous economic losses,but also cause social instability and serious damage of the ecological environment.Water pollution accident has become a potential threat of the China's water security and the quality of the water environment.Improving the water environment and reducing the impact of water pollution accident on human and ecosystem under the guidance of Scientific Concept Development are major issues that China's environmental protection faces in the new period. Because of the special geographical location and the importance of Three Gorges reservoir,it is very necessary to set up early warning indicator system of water pollution accident.Many scholars have studied target systems of environment and there are many people trying to set up safe target systems of water environment.However,the target systems are set up for the safety status of water environment and can't reflect the trends of long-term changes in water body;there is no study about the warning of water pollution accident occurring suddenly.Because of various reasons,early waming system in the water environment has not been really used and did not achieve its early warning function.After storage of the Three Gorges reservoir,the problem of water security was concerned by the people of all circles.So,we must set up an early warning system which can reflect the status of water environmental pollution in the reservoir area and prevent the occurrence of a major pollution incident.This study thoroughly summed up the new progress of studies about the target systems of environment at home and abroad in recent years.And on this basis,we tried to set up early-warning indicator systems of water pollution accidents occurring gradually and of emergency water pollution incidents.This article focused on the following aspects:(1) The characteristics and disadvantage of water pollution accidents were summarized in detail, pointing out that water pollution accidents has the uncertainty of space-time,pollution scope and object.It also pointed out not only they have the difficulty of treatment and the long-term of harm, but also have the uncertainty of the main emergency.(2)On the basis of researching index systems of environment at home and abroad,the guiding ideology,design principles and design ideas of the system have been discussed.Then early-warning indicators system of emergency water pollution incidents and early-warning indicators system of water pollution incidents occurring gradually which includes the goal layer,criteria layer,target layer were set up according to the characteristics of water pollution incidents and the specific situation of the Three Gorges reservoir area.After setting up the system frameworks,the weight of indicators were determined by the AHP,a comprehensive evaluation of the systems was given and the grades of water environment pollution accidents were divided.(3) For the needs of early-warning indicators system of emergency water pollution incidents, acute toxicities of aniline,xylene and nitrobenzene to silver carp were studied with short-term bioassay in laboratory.(4)Learning from related fields of emergency treatment mechanism,the response mechanism for water pollution accidents has been discussed and contingency measures corresponding to different water pollution cases on the status of grades were advanced.This study has shown that:by setting up the early warning indicators system of water pollution incidents and dividing the levels,the extent of water pollution and changes in the trend can be judged;the factors causing water pollution can be determined and the police function can be achieved in the early warning system;take appropriate emergency measures to prevent or reduce the impact of water pollution accidents to human and ecosystem.Finally,on the basis of the conclusion of full text,the aspect needing to be perfected about the choice of indicators and the level division in the system has been pointed out.