Study On The Risk Assessment Of The Sudden Cross-border Water Pollution Events In Songhuajiang

Sudden environmental pollution events are China's major security risks and the environmental issues which attract extensive attention of all levels of governments and the whole society because of their high uncertainty, great economic losses and serious environmental and ecological damage.The risk evaluation of the whole process of the river region pollution events has become a hot research topic in the environment science field. Songhua river region is chosen as the object of the cross-border environmental risk study based on its special characteristics of industry and cross border. The risk assessment system of the whole environmental pollution event process is set up for providing early warning of environmental contamination risk and emergency decision-making scientifically through evaluation research from the three aspects of advance, going on, afterwards.First, the properties, surrounding environment and risk offset of the risk sources are taken into the key consideration according to the characteristics of the industry and risk sources in Songhua River. The cross-border risk source classification index system is set up and classification standards are given in this paper.Secondly, appropriate pollution transportation models are selected considering the enormous variability in water transportation, end-result and the ways in which they cause harm to the environment between the soluble pollutants and insoluble pollutants. The time-space distribution in Songhua river region of the volatile phenol is determined by the two-dimensional non-steady-state analytical solution, and Fahey formula is used to study the oil spill pollution, the extended oil film, the drift location, as well as the harm to the sensitive points downriver. A pattern which can be used to identify the existence of environmental hazards, characterize the strength of environmental hazards, describe the accident hazard condition, and estimate the size of the accident hazardous area and the length of the accident hazard quickly is proposed based on the pollution band theory by combining the requirements of consequence assessment implementation. The trend of the pollution band, the arrival time of the pollution band and the hazard duration for the cross-border points can be real-time estimated through the pattern, so it is used in typical risk source I to provide a basic support for emergency treatment and disposal.Third, human health hazard of children, adolescents and adults around the cross bound caused by persistent low dose pollutant in Songhua River are calculated.At last, event classification index system of the sudden cross-border environment pollution is established after analyzing the characteristics of the events, and improved AHP-Fuzzy Comprehensive Evaluation Method is used to classify the event level. Songhua River water pollution incident data is collected to verify the index system, and the level of the cross-border incident caused by typical risk source I is determined.