【作者】 洪松；

【导师】 陈静生；

【作者基本信息】 北京大学 ， 自然地理学， 2001， 博士

【摘要】 本文以我国河流沉积物和海洋沉积物为例,研究了建立水体沉积物重金属质量基准中的几个主要问题。(1)首先阐明了沉积物重金属质量基准的概念和介绍了国内外研究进展;(2)在国外学者研究的基础上,提出了建立沉积物重金属质量基准的新的综合模型,在新模型中包括了能反映不同区域沉积物组成和性质、重金属化学行为和生物效应特点的众多新参数;(3)对河流沉积物的地球化学性质和表面性质进行了研究,讨论了模型中主要参数—重金属沉积物固相-水相分配系数(Kp)和各河段重金属水质基准(WQC)的确定方法,根据收集到的所研究河段水相和沉积物相的众多化学数据计算了其具体数值;探讨了AVS对沉积物中重金属生物有效性的影响;测定了长江、黄河部分河段、支流、湖泊及锦州湾沉积物中AVS的含量;(4)研究了沉积物中重金属对水生生物的“浓度-效应”关系:通过沉积物重金属加标实验,提出了长江、黄河沉积物中重金属对Q67淡水发光菌、蛋白核小球藻、大型蚤等代表性水生生物发生毒性效应和不发生毒性效应的阈限值;讨论了沉积物重金属污染对生物种数、密度、优势种类、群落多样性指数等水生生物群落结构特征的影响,提出了以沉积物综合污染指数(PA)和沉积物潜在生态风险指数(RI)表达的基准值;(5)应用多种方法研究了我国水体沉积物中主要重金属污染物的质量基准:利用自建模型计算了中国主要河流沉积物中Cu、Pb、Zn、Cd的质量基准值;应用“平衡分配法+生物效应法”较深入地探讨了长江和黄河沉积物中Cu、Pb、Zn、Cd、Ni、Cr、As、Hg的质量基准低值和质量基准高值的建议值,阐明了其建议依据;应用平衡分配法、沉积物生物效应数据库法、沉积物质量三合一法综合研究了渤海锦州湾沉积物中Cu、Pb、Zn、Cd、Hg的TEL值和PEL值。更多还原

【Abstract】 Metals and organic chemicals have contaminated most of rivers and lakes in the last 50 years. Due to their widespread release and persistent nature, metals such as cadmium, copper, mercury, nickel, lead and zinc are commonly elevated in aquatic sediments. These metals can poison benthic organisms that ingest particles of contaminated sediments. In addition, they can be released into overlying and pore waters to affect nonbenthic organisms. Thus, sediment toxicity concerns have historically focus of aquatic environmental protection and assessment activities in the world. The current water quality assessment guideline laid down by United Nations Environment Program (UNEP), United Nations Educational, Scientific and Cultural Organization (UNESCO) and World Health Organization (WHO) emphasizes the momentous significance of sediment quality. Many countries or regions including America, Canada, Australia and Hong Kong already derived sediment quality criteria for metals (SQC/metal) in 1990s.In China, no systematic and thorough researches have been carried out to develop sediment quality criteria for metals. The potential biological effects of freshwater and marine sediments are poorly understood to date. In this research, we used equilibrium partitioning approach to derive such criteria, which are compared with and revised by the site-specific metal/biological data. The main contents and results of our paper are as following:1. We clarified the concept of sediment quality criteria and sum up the international research developments in this area.2. Base on research work of foreign scholars, we provided a general model for developing SQC/metal. The model included many new parameters that can reflect both chemical composition and characteristics of sediment (e.g., pH, surface site density, surface acidity contents) from different regions and bioavailability of metals.3. We discussed how to ascertain some parameters in the model, such as Kp (partitioning coefficient for metals between sediment and water column), WQC (water quality criteria) and AVS (acid volatile sulfide). We also determined the AVS contents in some aquatic sediments in China and researched on the influences of AVS on bioavailability of metals in sediment.4. Using metal spiked sediment samples of the Yangtze River and the Yellow River, we determined toxicity of the samples to 3 kinds of representative aquatic organisms (including Vibrio qinghaiensis sp. Q-67, Chlorella valgaris and Daphnia magna) and worked out two criteria or assessment values of metals in sediments. The lower value, represented the concentration below which adverse effects were expected更多还原