【作者】 李阿梅；

【导师】 袁旭音；

【作者基本信息】 河海大学 ， 环境工程， 2006， 硕士

【摘要】 太湖是长江三角洲重要的湖泊,也是我国经济发展、人口稠密的地区。太湖流域的水环境状况直接影响着上海、无锡、苏州等大中城市的经济发展。由于近20年来这一地区工农业的高速发展,而相应的环境保护和污染防治措施不够及时,造成太湖流域的水质日益恶化,成为制约区域经济和社会发展的重要因素。本文采集了入太湖西部七条河流的水体和沉积物样品,它们分布于无锡市、宜兴市和常州市武进区等地,以此分析和统计入湖河道里微量元素在河道里的特征和污染情况,为入湖河道的污染治理问题提供基本依据,并探索微量元素在流域治理中指示污染源的价值和科学研究意义。 论文首先统计了研究河流重金属元素的含量,分析它们的特征,并把它们分别与水体标准值和沉积物重金属背景值比较。结果表明Zn、Pb、Cu、Ni均超过了背景值浓度,部分Cr略微超标,V基本未超标。在水体中各河流之间重金属含量变化都不大,但西湾河中的Zn的平均含量很低。且Ni在水体中的含量大于其他元素,这点与沉积物的情况明显不同。河流表层沉积物中重金属元素显示很大的变化性和不均匀性,变异系数按大小排列顺序为Zn>Pb>Cu>Cr>Ni>V>Co;所有河道中Pb的富集程度最高,其他元素按大小顺序排列是Cu>Zn>Ni>Cr,Co和V基本没有富集,反而有所亏损。由沉积物的生态质量标准评价得出,Zn、Cu、Pb、Cr四种金属在研究河道的生态风险较高。综合分析,研究区域大部分河流都有重金属污染,且污染元素主要是Zn、Pb、Cu、Ni,以及局部的Cr。 观察沿河各采样点微量元素,发现河流不同点的元素含量相差很大。微量元素含量的最高值一般都位于居民密集区、工业区,或在城镇生活工业污水排放口处或下游不远处。河道的重金属含量沿河也呈现一定的规律,在武进港、大浦河和梁溪河中几种重金属都呈现河流上游和入湖河口含量低,而河流中部高的“抛物线”现象,说明由于工业活动、居民生活造成的污染对河流的中间段的影响较大。因此,工业排污和生活污水的排放对河水中微量元素含量有着重要影响。 对三条代表性河流进行主成分分析得出结果:漕桥河是以工业污染为主的河流;大浦河以农业面源为主,有少量工业污染的河流;梁溪河则以生活污染为主,更多还原

【Abstract】 In China, Taihu lake is an important lake in the Yangtze delta where there is the area of developed economy and dense population. The water pollution of Taihu Lake has directly influenced on the economic development of the middle-big cities like Shanghai, Wuxi, Suzhou. Because of the rapid development of industry and agriculture, and being short of environment protection and measures of preventing the pollution in those areas, the water quality of Taihu Lake has become increasingly worse and turned into the important factors of impeding the economic and social development during the past two decades. In this dissertation, the samples of water and sediments were collected in seven rivers which flow through Wuxi, Wujin district of Changzhou, Yixing and enter into the Taihu Lake. Then, the characteristics of trace elements in water and sediments were analyzed, which could provide the information about solving the river pollution. Indications and environmental significances about trace elements in rivers were exploited in the research areas.The contents of trace elements in water and sediments were detected and calculated firstly. The characteristics of heavy metals were analyzed and those contents in water and sediments were compared with the standards of surface water and the soil background values respectively. It was found that Zn、 Pb、 Cu、 Ni、 Cr had been changed greatly by anthropogenic activities, but Cr in some degree, V basically not. The differences of the contents of dissolved heavy metals between seven rivers were not very much, but Zn in Xiwan River was very low. Among of all elements, Ni had the highest content in rivers. This point was different from that in sediments. The contents of heavy metals in sediments varied greatly in rivers, whose ranking of variation coefficient were Zn>Pb>Cu>Cr>Ni>V>Co. In seven rivers, Pb had the highest enrichment degree, others were ranked as follows Cu>Zn>Ni>Cr, but Co and V were depleted. According to thestandard of ecological qualities, it could be induced that the four metals of Zn> Cu> PtK Cr had high ecological risks. Viewed from the whole, the most part of the research areas had been polluted by heavy metals which mainly included Zm Pbs Ok Ni, and slightly Cr.Viewed from the trace elements along each river, it showed that those differences were great in different sites. The locations of high contents of trace elements were generally near the districts where there were dense population, developed industrial factories or outlet of wastewater in cities or towns. There are some rules that the contents of several heavy metals show a figure of parabola along Wujin River, Caoqiao River and Liangxi River. It is apparent that the middle of those rivers have been mostly affected by industrial and living sewage caused by human. Therefore, anthropogenic activities, especially the industrial discharge and living sewage in towns or cities have a considerably influence on elements in rivers.Doing the principle component analysis with three representative rivers, it was concluded that Caoqiao River was polluted mainly by industrial pollutants;Dapu River were major in non-point pollutants, including somewhat industrial pollution;Liangxi River were the river polluted mainly by living pollutants with slight industrial pollution.According to the geochemical characteristics of various elements and those different ratios, it can be included that Zn/Fe^ Fe/Mg> Pb/Fe^ K/Ca, Mg/Al could be used to distinguish the rivers which flowing into Taihu Lake polluted by different sources. At the same time, the molar ratios of metals can also provide the method to differentiate the polluted sources. The molar ratios of metals about water or sediment in seven rivers concerned can be divided, that’s to say, Caoqiao River and Mashan River belong into the same type, as well as Liangxi River and Xiwan River, but Dapu River is other type. They represent rivers polluted by industry, living and farm respectively. Therefore, some molar ratios can indicate the polluted sources effectively.Affected by human activities, the contents of REE in rivers flowing into Taihu Lkae varied greatly in a relatively short distance. The REE shale-normalized patterns of water were different from those of sediments. The water was HREE enrichment, while the sediment showed flat normalized REE patterns. What’s more, Eu and Ce in water wereenriched obviously while they in sediment have enrichment and depleted. Because of the differences of polluted sources around the rivers, the total contents and normalized patter of REE were obviously different. River polluted mainly by industrial pollutants show MREE enrichment and obviously positive anomalies of Gd;river polluted mainly by domestic sewerage show HREE enrichment and obviously positive anomalies of Eu;non-point polluted river show flat normalized REE pattern and the content of La is high.In conclusion, different rivers display the different polluted degrees of heavy metal and trace elements vary largely in places seriously affected by human activities. By analyzing and comparing the ratios of some trace elements and the REE characteristics, we can indicate the nature of the polluted materials in different rivers. It is greatly useful for the the Yangtze delta basin where its economic have well developed and exist river network.更多还原