| In recent years,hazardous chemicals transportation(HCT)is the second largest source for environmental emergency disasters in China.HCT emergency presents the characteristics of low-occurrence probability but serious environmental consequence.Hence,it is of extreme importance to precisely assess the environmental risk of HCT routines and minimize the impact of sudden environmental pollution,which has become the focus of environmental researches.At present,the studies on HCT risk assessment mainly focus on safety management,accident occurrence,personnel exposure and other hazardous consequences,while researches on the environmental impact of the accident,especially the impact on the accident point and downstream water environment,are still very limited,although they were highly valued by environmental emergency management.According to statistical analysis,among the secondary environmental emergencies of HCT,the accident scenario that poses the greatest threat to the water environment is the leakage of dangerous chemicals into the river.Therefore,this study aimed to establish a technical method for environmental risk assessment of road transportation sections of dangerous chemicals for sudden leakage into the river,which could provide a solution for the division of environmental risk level of road transportation sections of dangerous chemicals.This study explored the environmental risk assessment technology suitable for the needs of environmental emergency management in China.Based on the construction of the environmental risk assessment index factors and the study on their parameter values,this paper established a technical method of environmental risk assessment for HCT and developed the corresponding environmental risk assessment platform.Risk assessment on the transportation routes of hazardous chemicals involved by the largest HCT enterprise in China was also carried out.The obtained evaluation data would be applied to the company’s vehicle management system platform,and the mobile equipment suitable for risk road section early warning utilized by HCT enterprises was further developed.The main results were listed as follows:(1)According to the analysis of the temporal and spatial distribution,cause of occurrence,and influential factors of sudden environmental emergency of HCT in recent years,the estimation indices for sudden environmental emergency of HCT were determined,including type of hazardous chemicals,ratio of river input to leakage,migration and diffusion range,and types and distribution of sensitive targets in the downstream of the accident point.(2)By means of the combination of case statistical analysis with experimental research,the key factors affecting the sudden leakage of dangerous chemicals into the river were identified,and the relationship of road-river distance with leakage was also studied.When the road-river distance exceeded 200 m,the amount of dangerous chemicals entering the river after leakage was zero.When the road-river distance was within 200 m,the actual amount of dangerous chemicals entering the river could be obtained by multiplying the pollutant leakage amount and the proportion entering the river.Pollutant leakage amount was determined by transport amount,and the proportion into the river could be determined by type of hazardous chemicals and distance between road and river.(3)Based on the field measurement of flow velocity,instead of solving one-dimensional Saint Venant equations in the water quality model,a simplified one-dimensional water quality prediction model suitable for emergency needs was proposed to predict the river range where the water quality may not meet the standard after dangerous chemicals entered the river.The modeling time for simplified one-dimensional was short and the data demands was quite less.The simulation results were basically consistent with the traditional one-dimensional water quality model,which could be used as the migration and diffusion modeling of dangerous chemicals.(4)A set of working procedures for environmental risk assessment of road transportation sections of dangerous chemicals were established.Based on the specific data list and assessment target,an environmental risk assessment technology and the level standard for environmental emergency management were established by combining assessment indices and parameters with the circumstance modeling after emergency occurrence,and an appropriate partition standard for routine risk levels was also proposed.(5)The environmental risk estimation platform for HCT was established by integrating river space information,environmental sensitive target information,hydrological monitoring information of river and lake and pollution model analysis.The platform could achieve risk section estimation for single load or batch loads,which greatly reduced the manpower cost of environmental risk assessment and improved the working efficiency.(6)The application study of risk assessment method was carried out,and the mobile monitoring and early warning equipment was developed.The risk assessment method was successfully applied in the HCT routines in 10 provinces taken by China Petroleum Transportation Co.,Ltd.(hereinafter referred to as Petro China transportation company).The evaluation data were also implanted into the company’s vehicle management system platform.In the application process,the limitations of data use were found,so a mobile monitoring and early warning equipment was further developed,which achieved the integration of environmental risk assessment,management,vehicle location service and big data analysis,and improved the whole process management and control ability of environmental risks in road transportation of dangerous chemicals.In conclusion,this study established technical method,system platform and early warning equipment of environmental risk assessment for HCT.It can provide an important technical support for the optimization of national HCT routines,risk warning,and road risk prevention and control projects,which can reduce the environmental risk of HCT in the whole nation. |
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