The Study On The Regional Ecological Risk Assessment Of The Projects Of Excavation And Destruction Of Chemical Weapons Abandoned By Japan In Haerbaling Area

Based on the study status of ecological risk assessment, the paper builds a regionalecological risk assessment system for the projects of excavation and destruction of chemicalweapons in Haerbaling abandoned by Japan in China, adopting present methods ofecological risk assessment. It includes the regional limits of the study area, introduction of theregion and the analysis of the status of the regional eco-environment quality, analysis of risksource and suffers from the risk, choice of assessment endpoints, the exposure ways,analysis and calculation of exposure concentration, movement and transformation of toxicsubstance and pollutants, dose-response relationship, risk characterization, nondeterminacyanalysis and countermeasure for regional ecological risk management. The paper primarystudies on the principles for choosing risk suffers and assessment endpoints, exposure ways,analysis and calculation of exposure concentration, movement and transformation of toxicsubstances and pollutants, dose-response relationship and risk characterization.The paper suggests follow principles to choose risk suffers: 1) play an important role inthe food chain and web.2) sensitive to the pollutants and natural sceurge.3)special value forhumankind.4)important habitat and ecosystem which keep the regional environmenthealthy.5)can indicate important changes of systems. Guaranteeing the all sidedness,hierarchy, maneuverability and commonality, it suggests follow principles to chooseassessment endpoints: 1) response quickly to dangers. 2) reflect characteristics ofecosystem structure and function. 3)predictability. 4)quantification. 5)large applied range.The paper studies the movement of main toxic substances in environment anddose-response relationship. According to the hypothesis that the unit area of a body absorbssame dose toxic substance, and that there is no difference between different kinds of animalson the sensitivity to toxic substances, it converts the dose from one kind to another kind,based on the relationship among weight, total body area of a animal and breath rate. Theresults make foundations for ecological risk assessment.It predicts the distribution of toxic substances 20km around the accident spot in all kindsof accidents. Considering the factors of importance of different kinds of eco-systems in thestudy area, distance away from accident spots, predominant wind direction, sensitivity andfrangibility of eco-systems, source of pollutants, spread speed and arriving time of pollutants,it chooses ten sensitive spots representing all kinds of eco-systems. Through calculating toxicsubstances concentration and dose accumulating in risk suffers'body in every sensitive spot,it analyzes the safe situation in every kind of accident. It adopts evaluating indicators from OPP and the quotient method to characterize risk.The study indicates that in the situation of small wind, the unacceptable range of birds is 7kmin the down-direction of wind, and the frogs is 27km. the exposure dose of toxic substances isup the standers in most sensitive spots, in level of unacceptable risk. The birds in sensitivespots suffered much from projects of excavation, 80% of sensitive spots are in dangerouslevel.Finally, according to assessment results and the characteristics of the regionaleco-environment and the projects, it proposes countermeasures for regional riskmanagement in aspects of precautionary measure, emergency measure and environmentalmonitoring.