目前我国正处在社会与经济发展的转型期，也是突发环境事件高发期，由企业化学品事故引发的水突发环境事件对区域河流水环境带来的环境风险是当前严峻的环保问题之一，关系到广大人民群众的生命财产安全，开展区域水环境风险评价方法研究具有重要意义。我国至今没有一套适合中国国情、适用于环境应急管理的区域水环境风险评价方法。本文以企业化学品泄漏为例，对区域水环境风险评价方法进行了系统研究。本文研究了国内外大量化学品事故引发的水环境突发事件，确定了企业化学品事故引发的水突发环境事件对区域河流水环境带来的环境风险的研究对象。通过比较化工业普遍使用的环境风险评价方法，确定了区域水环境风险的评价框架。建立的评价方法的基本假设是：企业存在潜在的化学品泄漏风险；区域水环境对泄漏越敏感、接触到泄漏的受体越多，一旦发生突发环境事件后，区域水环境风险就越大。本文建立了适用于水环境的企业环境危险性评价方法。结合我国国情列出企业环境危险性评价时使用的环境风险物质清单。建立的阈值法分别定义三个不同的环境危险性指数值，根据企业所含环境风险物质量的大小进行赋值，但这样的方法难以划分企业之间的差异。因此，在阈值法基础上建立企业环境危险性评价连续函数法。结合大量的水突发环境事件典型案例，考虑对水环境的影响，确定选择三种敏感水环境风险受体，分别是饮用水源区、农业用水区和工业用水区，其中饮用水源区的权重最大，工业用水区的权重最小。三种水环境风险受体的脆弱性分别表征为区域水环境内以河水为主要水源的居民数量、农业和工业取水量的函数。开展区域水环境风险评价。首先通过企业所影响到的河流把化学品运移的距离和水环境风险受体的脆弱性等参数，把企业对水环境风险受体的影响进行量化，建立了企业区域水环境脆弱性评价阈值法和更加精确的连续函数法。然后根据企业环境危险指数和企业区域水环境脆弱性指数计算企业区域水环境风险指数。进一步开展子区域水环境风险评价，根据地理、行政等划分区域的标准，把各区域内的企业区域水环境风险指数求和，根据其数值大小划分区域的级别。选择企业较为集中的湖南省长沙市、江苏省句容市，对区域水环境风险评价方法进行了应用。筛选出了长沙市3家危险企业；计算得到了江苏省句容市31家企业的企业环境危险指数、企业区域水环境脆弱性指数和企业区域水环境风险指数；区域水环境风险评价结果显示该市3个子区域的水环境风险值存在显著差异；比较了区域水环境风险评价阈值法和连续函数法，认为区域水环境风险评价连续函数法操作简单、更具实际应用价值。

With the economic development and social transition，a mass of environmental emergencies come forth in China. Environmental risk, especially regional water environmental risk (RWER) caused by chemical accidents has become one of the most severe environmental issues which can impact on the safety of public lives and properties. Therefore it is significant to study the methods to assess the regional water environmental risk. However, in China, there are not any technique and method，which can apply for national conditions，to assess the regional water environmental risk yet. In this paper, following the case study of chemical spills in the enterprise, the method of regional water environmental risk assessment was studied.The research objective was determined as regional water environmental risk through research on quantities of water environment emergencies caused by chemical accidents. The framework of regional water environmental risk assessment was determined through comparative environmental risk assessment methods commonly used in chemical industry. In this paper，the basic assumption for this method is that potential spill risk exists in enterprise. Generally，the more sensitive to spill and the more targets close to spill，the greater the regional water environment risk is once environmental emergency happens. In this paper, a method to assess the hazard of enterprise was established. Combining conditions of China, the hazardous substances were listed for hazard assessment of enterprises. The established threshold method defined three different indexes according to the quantity of hazardous substances. But, it ignored the differences among enterprises. So, the method based on the continuous function was established. Based on a large number of typical cases of water environmental emergencies, three sensitive environmental risk receptors were selected, including the urban areas, agricultural areas and industrial areas. The urban areas have the most weight while industrial areas have the least weight. The vulnerability of three environmental risk receptors was characterized by the population who live on river as their main water resource in regional water environment, the quantity of agriculture and industrial intakes respectively.The regional water environmental risk assessment was carried out. Firstly, the effects on the water environmental receptors were quantified according to shipment distance of chemicals in the river after spill and vulnerability of environmental risk receptors. The threshold method and continuous function method for vulnerability assessment were built. Furthermore, the enterprise regional water environmental risk index was calculated according to the hazard index and vulnerability index. Based on the geography and administration, the sub-regions were divided. Then the sub-regional environmental risk were calculated and ranged by cumulating the risk index of all enterprises in the sub-region.The method of regional water environmental risk assessment was applied in Changsha, Hunan Province, and Jurong, Jiangsu Province because of their concentrated industries. The results showed that three dangerous industrial enterprises were filtered out; the hazard index, vulnerability index and risk index of thirty-one industrial enterprises were figured out in Jurong; significant differences were found among the water environmental risk values of sub-regions in Jurong according to the results of regional water environmental risk assessment; compared with the threshold method, the continuous function method was more simple and easier for application on the regional risk management.