辽河口滨海湿地沉积物重金属污染评价分析

发布时间：2018-04-28 10:08

本文选题：辽河口 + 沉积物　；参考：《中国地质大学(北京)》2015年硕士论文

【摘要】：本文以辽河口滨海湿地表层沉积物和河口心滩柱状沉积物为研究对象,测试分析22个表层沉积物样品和柱状沉积物中的粒度组分、有机碳含量、微量元素含量和210Pb、137Cs的比活度等,通过分析湿地表层重金属元素的分布特征和元素之间的相互关系,垂向上重金属的分布特征及其影响因素,探析河口心滩沉积物30年的重金属污染历史,评价重金属的污染等级和潜在生态危害程度,主要获得以下四条结论:(1)重金属元素在研究区域形成了一定程度的富集。其分布特征大致分为四类:①Cr、Cu、Zn三种重金属元素在流子沟河上游地区存在高值;②As、Pb的高值集中分布在小道河上游河道狭窄地区;③Cd的高值区集中在整个小道河上游地区;④Hg元素的高值区集中在整个研究区的北区,即富集在流子沟河、小道河两条支流上游地区。重金属元素均表现为向入海方向含量逐渐减少的趋势。(2)柱状沉积物中As、Hg、Cr、Cd、Cu、Pb、Zn七种重金属元素富集在黏土组分中,同时与有机碳含量有很好的正相关性,表明水动力条件、细颗粒物质及有机碳含量综合影响了重金属元素的分布。(3)辽河口心滩沉积物各段的沉积速率为:1984~1998年间约为3.00cm/a,1998~2013年间沉积速率为3.73cm/a。获得心滩柱状沉积物沉积时间约为30a。(4)通过地累积指数法和潜在生态危害指数法两种重金属元素污染方法评价得出:①整个研究区内表层沉积物中重金属Cd和Pb表现为低污染水平,其中重金属Cd为中度生态危害,此外其他重金属元素表现为无污染或低生态危害;②心滩柱状沉积物中Cd元素在各个层位出现了偏中度、轻度的污染,同时在相同层位也出现中等或较重的生态危害,表明在30年的沉积历史中,辽河口心滩存在一定的Cd污染;其他重金属As、Hg、Cr、Cu、Pb和Zn在研究区内30年内的沉积历史中,无重大污染事件的发生。
[Abstract]:In this paper, the surface sediments of Liaohe estuary coastal wetland and the columnar sediments of estuarine banks were studied. The particle size composition, organic carbon content, trace element content and specific activity of 210PbC137Cs in 22 surface sediment samples and columnar sediments were measured and analyzed. Based on the analysis of the distribution characteristics of heavy metals in the surface layer of wetlands and the relationship between the elements, the distribution characteristics of heavy metals in vertical direction and their influencing factors, the history of heavy metal pollution in estuarine sediments for 30 years is analyzed. In order to evaluate the pollution grade and potential ecological hazard of heavy metals, the following four conclusions were obtained: (1) heavy metals were enriched to a certain extent in the study area. Its distribution characteristics can be divided into four types: 1: 1CrCU Cu Zn three kinds of heavy metal elements in the upper reaches of Liuzigou River there is a high value of 2As-Pb concentration in the upper reaches of the Xiaodao River channel narrow area of the high value of CD concentrated in the upper reaches of the whole small river area; The high value region of 4Hg is concentrated in the north of the whole study area, that is, concentrated in the upper reaches of two tributaries of Liuzigou River and Xiaodahe River. The contents of heavy metals in the columnar sediments show a decreasing trend towards the sea. (2) the seven heavy metal elements of AsHgGfus cu, Pb, Zn are enriched in clay, and there is a good positive correlation with the content of organic carbon, which indicates that the hydrodynamic conditions are suitable for the accumulation of heavy metal elements, and the results show that the heavy metal elements are highly correlated with the contents of organic carbon, indicating the hydrodynamic conditions. The sedimentation rate of each section of Liaohe estuary sediment is about 3.00 cm / a from 1984 to 1998 and 3.73 cm / a from 1998 to 1998.The distribution of heavy metal elements is influenced by the content of fine particles and organic carbon. The sedimentation time of columnar sediment in Xintan is about 30 a.f.) the heavy metal CD and Pb table in the surface sediments of the whole study area of the whole study area was obtained through the evaluation of heavy metal element pollution by the method of ground accumulation index and the method of potential ecological hazard index. It is now at a low level of pollution. The heavy metal CD is a moderate ecological hazard, and the other heavy metal elements in the columnar sediments with no pollution or low ecological hazard are moderately or mildly polluted in each layer. At the same time, there are moderate or heavy ecological hazards in the same horizon, which indicates that in the 30 years of sedimentary history, there is some CD pollution in Liaohe estuary central beach, and other heavy metals, such as As-HgCU, Cu-Pb and Zn, have been deposited in the study area in the past 30 years. There were no major pollution incidents.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X824

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