【作者】 朱先涛；

【导师】 朱端卫； 华玉妹；

【作者基本信息】 华中农业大学 ， 环境工程， 2009， 硕士

【摘要】 随着经济发展和人们生活水平的提高,大量的生产和生活污水排入湖泊,导致湖泊富营养化和重金属污染等众多环境问题出现并日益加剧,其中湖泊水体环境中重金属对富营养化的影响值得关注。本文研究了不同水力条件下重金属Cd对富营养化水体营养特性的影响。研究选用了武汉两个不同富营养化程度的湖泊(东湖和南湖)作为研究对象,用相应的湖水作为反应水柱上覆水,上覆水中Cd浓度设置了0mg/L、5mg/L和50mg/L3个水平,用Cd-0、Cd-5和Cd-50表示,试验分别在静态和动态两种水力条件下进行,主要探讨了重金属Cd与上覆水中营养元素氮、磷以及沉积物中总磷、全氮、碱性磷酸酶活性、脲酶活性之间的互相关系。主要结果如下:1、上覆水中添加了不同浓度的Cd之后,Cd逐渐被沉积物吸附,Cd在上覆水中的浓度渐渐变小。不同来源的沉积物Cd的吸附速率不同;静态水力条件下南湖沉积物对Cd的吸附速率比动态水力条件下大。2、一定条件下Cd可以抑制沉积物中总磷的释放,抑制程度与水力条件和湖泊营养特性有关。在静态水力条件下和Cd-5和Cd-50处理中,富营养化程度高的南湖中,Cd能够显著地抑制沉积物总磷向上覆水释放。Cd的浓度越大,抑制作用越明显;在动态水力条件下,东湖Cd-50处理中Cd能够抑制沉积物总磷的释放,而Cd-5处理表现不明显。3、在静态水力条件下,东湖和南湖Cd-5和Cd-50处理上覆水中Cd抑制沉积物释放溶解性磷酸盐显著;在动态水力条件下,东湖和南湖Cd-5和Cd-50处理的上覆水中Cd也能够抑制沉积物释放溶解性磷酸盐,但由于动态水力条件引起的综合性因素使得Cd-50处理中表现的抑制作用比Cd-5处理更显著些。4、静态和动态水力条件下,东湖和南湖各处理中Cd对上覆水中总氮的影响均不显著。5、静态水力条件下,对于富营养化程度较低的东湖,各处理中的Cd对上覆水中氨氮没有明显抑制作用,而富营养化程度较高的南湖,Cd-5和Cd-50处理对氨氮的内源释放有一定的抑制作用。动态水力条件下,在试验后期,东湖和南湖Cd-50处理中Cd对氨氮的释放有显著的促进作用。6、在静态试验中,东湖和南湖各处理在不同阶段,沉积物中碱性磷酸酶活性变化不同。试验前期,沉积物中碱性磷酸酶活性在Cd-0、Cd-5和Cd-50处理中依次减弱;试验后期,沉积物中碱性磷酸酶活性呈依次增强的趋势。在动态试验中,东湖各处理沉积物中碱性磷酸酶活性变化比较复杂;南湖Cd-50处理对碱性磷酸酶活性有明显的抑制作用。7、东湖和南湖各处理之间,沉积物中脲酶活性没有显著差别,Cd对脲酶活性没有显著影响。更多还原

【Abstract】 With the development of economic and the improvement of people’s living standards, a large number of production wastewater and domestic sewage was discharged into the lake, causing eutrophication and heavy metal pollution in lakes and many other environmental problems. The environmental problem destroyed the ecological environment, affected people’s health, survival and the socio-economic sustainable development.This paper studied the influence of cadmium (Cd) input on the nutritional properties of eutrophic lakes in different hydraulic conditions. Water and sediment of two different eutrophication degree lakes (Lake Donhu and Lake Nanhu) in Wuhan City were studied as tested overlying water and tested sediment in the reaction columns, and the Cd concentrations in overlying water were set 0mg/L, 5mg/L and 50mg/L three levels, expressed by Cd-0, Cd-5 and Cd-50, then the study was run in static and dynamic hydraulic conditons respectively. This paper discussed the relationships between Cd and nutrients in overlying water and total phosphorus, total nitrogen, urease activity, alkaline phosphatase activity in sediments. The main conclusions of this paper were listed below:1. After Cd was added into overlying water, Cd was adsorbed by sediments gradually, and Cd concentrations in the overlying water became low gradually. The Cd adsorption rates by sediment were different between Lake Donghu and Lake Nanhu, and the Cd adsorption rate by Lake Nanhu sediment in static condition was larger than that in dynamic conditon.2. Cd could inhibit the release of total phosphorus from sediment and the inhibition which was in relation to the hydraulic condition and the nutrient characteristics of lakes. In static hydraulic conditon, Cd in the Cd-5 and Cd-50 treatments of higher eutrophication degree Lake Nanhu inhibited the release of total phosphorus obviously. In dynamic hydraulic condition, Cd in the Cd-50 treatment of Lake Donghu inhibited the release of total phosphorus obviously, but did not in the Cd-5 treatment; Cd in the Cd-5 and Cd-50 treatments of Lake Nanhu could inhibit the release of total phosphorus, and the higher the Cd concentration, the more obvious inhibition.3. In static hydraulic condition, Cd in the Cd-5 and Cd-50 treatments of Lake Donghu and Lake Nanhu inhibited the release of soluble phosphate from sediments obviously. In dynamic hydraulic conditon, because of the factors caused by dynamic hydraulic conditon, the inhibition in the Cd-50 treatment was more obvious than that in the Cd-5 treatments.4. The effects of Cd to total nitrogen in the overlying water were not obviously in the treatments of Lake Donghu and Lake Nanhu. 5. In static hydraulic condition, the effects of Cd to ammonia-nitrogen concentrations in the treatments of Lake Donghu were not obviously. But to the higher eutrophication degree Lake Nanhu, Cd of Cd-5 and Cd-50 treatments could inhibited the release of ammonia-nitrogen. In dynamic hydraulic conditon, Cd in the Cd-50 treatments of Lake Donghu and Lake Nanhu promoted the release of ammonia-nitrogen in the later period of the test.6. In static hydraulic conditon, the changes of alkaline phosphatase activity in sediments of Lake Donghu and Lake Nanhu treatments were different in different phases. In dynamic hydraulic conditon, the changes of alkaline phosphatase activity in sediments of Lake Donghu treatments were complicated; the alkaline phosphatase activity of Cd-50 treatment in sediments of Lake Nanhu was inhibited obviously.7. The urease activity in sediments of Lake Donghu and Lake Nanhu treatments did not change obviously, and the inhibition of Cd to urease activity was not obviously.更多还原