洞庭湖流域区域生态风险评价  

The regional ecological risk assessment of the Dongting Lake watershed

作　　者：卢宏玮[1] 曾光明[1] 谢更新[1] 张硕辅[1] 黄国和[1] 金相灿[1] 刘鸿亮[1] 

机构地区：[1]湖南大学环境科学与工程系,长沙410082

出　　处：《生态学报》2003年第12期2520-2530,共11页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目 (70 1 71 0 5 5;5 0 1 790 1 1 ) ;国家杰出青年科学基金资助项目 (5 0 2 2 5 92 6) ;高等学校博士学科点专项科研基金资助项目 (2 0 0 2 0 5 3 2 0 1 7) ;2 0 0 0年教育部高等学校优秀青年教师教学科研奖励计划资助项目~~

摘　　要：对于生态系统 ,灾害性事件的产生多为外界胁迫因素与系统内部生态结构不稳定性因素共同作用的结果 ,因此对流域生态风险进行评价时应充分考虑系统内部的生态结构与外界的胁迫性因素。目前国内外对于外界胁迫性因素的研究多集中在自然灾害 (如洪涝灾害 )以及外界污染物主要集中在重金属类的排入 ,而事实上 ,其他类型的污染物 ,如氮、磷等也将对生态系统产生一定的危害 ,由于这些污染物浓度在个别地区超标程度较高并可能对受体产生巨大的影响 ,因此将该类污染物作为一类重要因素纳入生态风险评价体系中是非常必要的 ,而由此得出的评价结果也更为系统和全面。以洞庭湖地区的东、南、西三部分作为研究区域 ,根据其特殊的背景 ,将工业污染、农业污染及血防污染作为其污染类风险源 ,引入由氮毒性污染指数、磷毒性污染指数、重金属类毒性污染指数共同构成的毒性污染指数与自然灾害指数和系统本身的生态指数 ,包括生物指数、多样性指数、物种重要性指数以及脆弱性指数完成了对洞庭湖流域的区域生态风险评价。In ecosystem, the generation of catastrophic events arises from the cooperative impact of the external stressing factors and the internal unsteady factors existing in an ecological structure, which should be fully taken into account for regional ecological risk assessment. At present, research on external stressing factors is much focused on the natural disasters (such as storm flood disasters) and research on external contaminants is in large part concentrated on discharged heavy metals. But in fact, other contaminants such as nitrogen and phosphorus can also lead to harmfulness to ecosystem. Due to the high level of the concentration of these contaminants in excess of standard and their great effect on receptors, it is necessary to regard them as important factors and to introduce them into ecological risk assessment system. Such a choice is to ensure the assessment results being more systematic and comprehensive.Daphnia, as a receptor in this paper, is employed for analysis of the ecological risk of the east, south and west parts of Dongting Lake. Based on the historical information, flood disaster, industrial pollution, agricultural pollution and anti-schistsome infection pollution are selected as risk sources, and exposure assessment as well as hazard assessment has also been conducted. In the process of ecological risk assessment, toxicity pollution indexes (aims at N, P, heavy metals and so on), which characterize effect of toxic contamination on normal life of receptor, are defined by the ratios of normal concentration to Lethal Concentration 50～48 hours (LC_(50)-48). For heavy metals, owing to a lot of research on them, we can get toxicity pollution index values easily. However, it is hard for TN (total Nitrogen), TP (total phosphorus) to get their values due to the lack of research on LC_(50)-48 of TN and TP abroad and at home. As a result we propose an extrapolation method to calculate the toxicity coefficient and acquire their values of 1.4 and 27, and thus estimate toxicity pollution index of TN an

关 键 词：生态风险评价 洞庭湖 污染 生态结构 生态系统 灾害 流域区域 

分 类 号：X820.4[环境科学与工程—环境工程]