本文關鍵詞：大渡河流域石棉段沉積物重金屬污染及生態(tài)風險評價　出處：《成都理工大學》2015年碩士論文　論文類型：學位論文

  更多相關文章： 大渡河流域石棉段 水系沉積物 重金屬污染 潛在生態(tài)風險評價

【摘要】：以大渡河流域石棉段水系沉積物中的重金屬為研究對象,在通過水系沉積物1:5萬區(qū)域地球化學調查,重點分析了大渡河流域石棉段水系沉積物中重金屬元素As、Cd、Cr、Cu、Hg、Ni、Pb、Zn的總量和富集分異特征,并通過相關性分析和聚類分析方法來研究水系沉積物中8種重金屬元素的相互關系,初步應用兩種常用地積累指數法和潛在生態(tài)危害指數法兩種污染評價方法對研究區(qū)沉積物中的重金屬污染進行了評價,取得結論如下:選取中國沉積物綜合平均值、中國水系沉積物背景值、長江沉積物背景值、中國土壤背景值和四川A層土壤背景值5種指標作為參考背景值,研究大渡河流域石棉段水系沉積物重金屬元素總量特征,除了As元素平均含量低于長江沉積物背景值外,各元素平均含量均高于參考背景值;8種元素最小值都小于5項參考背景值,以中國水系沉積物背景值為例,8種元素的最大值是背景值的幾十倍到上千倍,如Cd的最大值是背景值的192倍、Pb的最大值是背景值的1044倍等,說明大渡河流域石棉段沉積物受到相當程度的重金屬污染。與長江沉積物重金屬含量背景值相比,大渡河流域石棉段沉積物中重金屬含量富集程度和分異程度較高。從富集系數來看,重金屬元素富集程度依次為PbCdHgNiCrZnAsCu。從變異系數來看,大渡河流域石棉段沉積物重金屬含量有較大的變異。其中As、Cd、Cu、Hg、Pb的變異系數都在2以上,屬于極強分異型。相關性分析結果顯示,在水系沉積物中As、Cd、Cu、Pb和Zn元素間具有良好的相關性;Cr與Ni之間有顯著的正相關;Hg與其他元素相關性都比較差。聚類分析結果顯示沉積物中8種重金屬元素可以分為As-Cu-Pb、Cd-Zn、Hg和Cr-Ni四類組合關系。這兩種分析方法表明研究區(qū)重金屬污染是人為作用和自然作用共同導致的結果。研究區(qū)重金屬污染進行的潛在生態(tài)風險評價主要運用地積累指數法和潛在生態(tài)危害指數法,兩種方法評價結果具有高度的一致性。Cd屬于中度-嚴重污染,強-極強生態(tài)危害,中度及以上污染點75處,強及以上生態(tài)危害點257處,是潛在生態(tài)危害指數最主要的貢獻者。Pb、Hg次之,Pb屬于中度-嚴重污染和中等-強生態(tài)危害,Hg屬于中度-偏重污染和中等-很強生態(tài)危害。As、Cu屬于中等-偏重污染和中等-強生態(tài)危害,Cr、Ni、Zn屬于中度-偏重污染和輕度生態(tài)危害。大渡河流域石棉段水系沉積物總體上屬于中等生態(tài)危害,污染程度屬于中度-偏重度污染,其中Cd、Pb和Hg尤其值得關注。
[Abstract]:The section of the Dadu River Valley asbestos heavy metals in sediments as the research object, through sediment 1:5 000 regional geochemical survey, focuses on the analysis of heavy metals in the Dadu River section of asbestos in sediments As, Cd, Cr, Cu, Hg, Ni, Pb, Zn and the total concentration distribution, the relationship between and through the correlation analysis and cluster analysis method to study the 8 kinds of heavy metal elements in the sediments, preliminary application of two kinds of commonly used heavy metals accumulation index and potential ecological risk index method of two kinds of evaluation methods for pollution in the study area in sediment pollution was evaluated. The conclusions are as follows: the selection of Chinese sediment average, Chinese river sediments of Yangtze River Sediment background value, the background value, the background value of soil Chinese and Sichuan A layer soil background values of 5 indicators as reference background value, on the Dadu River section of water flow domain asbestos sink The accumulation of heavy metals in addition to total characteristics, the average content of As is lower than the background value of elements of Yangtze River sediment, the average content of each element were higher than the reference background value; 8 elements are less than the minimum value of 5 reference background value, to China sediment background values of 8 elements for example, the value is the background value of several times thousands of times, such as the maximum value of Cd is 192 times higher than the background value, the maximum value of Pb is 1044 times higher than the background value, that the sediment in the Dadu River section of asbestos by the heavy metal pollution degree. Compared with the background value of heavy metal content in the sediments of Yangtze River, the enrichment of heavy metals in sediments of the Dadu River valley section and asbestos a higher degree of differentiation. The enrichment coefficient, the enrichment of heavy metal elements in PbCdHgNiCrZnAsCu. from the aspect of variation coefficient, variation in the Dadu River section of asbestos heavy metals in the sediments of the As, Cd, Cu, Hg, the coefficient of variation of Pb in more than 2, which belongs to the strong differentiation. The results of correlation analysis showed that in sediments As, Cd, Cu, Pb and Zn have a good correlation between the elements; there was a significant positive correlation between Cr and Ni; the correlation between Hg and other elements are relatively poor clustering analysis results showed that the 8 kinds of heavy metals in the sediments can be divided into As-Cu-Pb, Cd-Zn, Hg and Cr-Ni four kinds of combination. The two methods show that the heavy metal pollution in the study area is artificial and natural effect due to the heavy metal pollution in the area. Potential ecological risk in the evaluation mainly uses the method of index of geo accumulation and the potential ecological risk index method, evaluation results of the two methods is consistent with the height of the.Cd belongs to moderate pollution, strong extremely strong ecological harm, moderate pollution and over 75, and more than 257 points of ecological risk, potential ecological risk The main contribution of damage index of.Pb, Hg, Pb belongs to moderate pollution and medium strong ecological harm, Hg belongs to moderate - and medium - strong emphasis on pollution ecological risk.As, Cu belong to the middle - and medium - strong emphasis on pollution and ecological damage, Cr, Ni, Zn belongs to moderate pollution stress and mild ecological hazard. The Dadu River valley section of river sediment asbestos is generally moderate ecological risk, the degree of pollution belongs to moderate emphasis of pollution, including Cd, Pb and Hg of particular concern.

【學位授予單位】：成都理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：X52;X826

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本文編號：1378060