次生季節(jié)性河流底泥元素的分布特征分析
發(fā)布時間：2019-01-26 20:23
【摘要】：在水資源相對匱乏且季節(jié)分配不均的淮河流域修建了大量的小型水壩,改變了河流流態(tài),形成了大量的次生季節(jié)性河流。在半濕潤、半干旱區(qū),由于基流相對較少,河流水體更易受到污染,特別是不易轉(zhuǎn)化的重金屬污染,往往易在河流中累積,造成生態(tài)危害。底泥是重金屬、有機(jī)碳及其他營養(yǎng)元素的重要聚集處,也是營養(yǎng)鹽再生的主要場所。淮河流域作為我國社會經(jīng)濟(jì)發(fā)展較為重要的地區(qū)之一,也面臨著嚴(yán)重的底泥污染問題。在水資源相對匱乏且季節(jié)分配不均的淮河流域修建了大量小型水壩,對河流流態(tài)影響顯著,改變了河道沉積環(huán)境,催生了大量的次生季節(jié)性河流,也將影響各種重金屬元素及N、P等營養(yǎng)元素在河流底泥中的分布。本文以位于河南省滎陽市的淮河4級支流索河為研究對象,應(yīng)用實(shí)測值與環(huán)境背景值比較及冗余分析(平均粒徑、分選系數(shù)、平均曲率、植被生物量、蓋度等環(huán)境影響因子)等方法對河道沉積物中重金屬元素、N、P及有機(jī)碳含量等在河道不同區(qū)段的分布特征進(jìn)行了研究。結(jié)果發(fā)現(xiàn)：(1)河道中不同采樣點(diǎn)間沉積物中各元素含量存在較大差異,且不同元素間的富集程度不同。Cd、Hg、Zn等重金屬元素及N、有機(jī)碳等的含量均高于環(huán)境背景值；As、Cr、Cu、Mn等重金屬含量總體上均低于環(huán)境背景值,Cd、Zn兩種重金屬含量顯高于國家一級標(biāo)準(zhǔn)值。Cd、Hg、Zn等重金屬元素及N、有機(jī)碳的含量變異系數(shù)相對較大(0.401-0.550),這些元素及有機(jī)碳在研究區(qū)河道內(nèi)不同采樣點(diǎn)間變化差異較大；而As、Cr、Cu、Pb、Mn、Ni等重金屬元素及P的含量的變異系數(shù)相對較小(0.087-0.215),其分布特征受河道微生境條件異質(zhì)性的影響相對較小。河道不同區(qū)段間的生境異質(zhì)性影響元素在底泥中的富集效應(yīng),但不同元素的響應(yīng)強(qiáng)度及響應(yīng)模式存在一定差異。(2)河道不同區(qū)段間沉積物粒級結(jié)構(gòu)存在較大差異,在庫塘相,沉積物平均粒徑較大的采樣點(diǎn)主要位于凸型岸線區(qū)段,沉積物分選系數(shù)較大的采樣點(diǎn)主要位于凹型岸線區(qū)段；沉積物平均粒徑變化較大的采樣點(diǎn)主要位于庫塘段；而在河流相,沉積物平均粒徑變化較小的采樣點(diǎn)多位于植被生長狀況較為良好的區(qū)段,河道段沉積物分選系數(shù)變化較小。(3)冗余分析結(jié)果顯示,植物生長狀況良好河段其沉積物中重金元素含量相對較小,而岸線相對曲折,有利于沉積過程的河段的底泥中的重金屬元素、有機(jī)碳等的含量相對較高。沉積物平均粒徑越小,沉積物分選性越好,底泥中重金屬含量相對較高。
[Abstract]:A large number of small dams have been built in the Huaihe River basin, where water resources are relatively scarce and the seasonal distribution is uneven, which has changed the river flow pattern and formed a large number of secondary seasonal rivers. In semi-humid and semi-arid areas, the river water is more vulnerable to pollution, especially the heavy metal pollution, which is difficult to transform, because of the relatively small basic flow, which often accumulates in the river and causes ecological harm. Sediment is an important accumulation of heavy metals, organic carbon and other nutrients, and is also the main place for nutrient regeneration. As one of the most important social and economic development areas in China, Huaihe River Basin is also faced with serious sediment pollution. A large number of small dams have been built in the Huaihe River basin, where water resources are relatively scarce and the seasonal distribution is uneven, which has a significant impact on the flow pattern of the river, which has changed the sedimentary environment of the river and created a large number of secondary seasonal rivers. It will also affect the distribution of various heavy metals and nutrient elements such as Nu P in river sediment. In this paper, the Huaihe River, a grade 4 tributary of the Huaihe River, located in Xingyang City, Henan Province, is taken as the research object. The comparison between the measured value and the environmental background value and redundant analysis (mean particle size, sorting coefficient, mean curvature, vegetation biomass) are applied. The distribution characteristics of heavy metal elements, NBP and organic carbon in river sediment were studied by means of environmental impact factors such as coverage and so on. The results are as follows: (1) the contents of elements in sediments of different sampling sites are different, and the enrichment degree of different elements is different. The contents of heavy metals such as Cd,Hg,Zn, N and organic carbon are higher than those of environmental background. The contents of As,Cr,Cu,Mn and other heavy metals were all lower than the environmental background values, and the contents of Cd,Zn and Cd,Zn were higher than those of the first class national standard. The coefficient of variation of organic carbon content is relatively large (0.401-0.550). However, the coefficient of variation of heavy metal elements such as As,Cr,Cu,Pb,Mn,Ni and P was relatively small (0.087-0.215), and its distribution was influenced by the heterogeneity of microhabitat conditions. Habitat heterogeneity affects the enrichment effect of elements in sediment, but the response intensity and response mode of different elements are different to some extent. (2) there are great differences in sediment grain structure among different sections of river. In the reservoir and pond facies, the sampling points with larger average sediment diameter are mainly located in the convex shoreline section, and the sampling points with higher sediment sorting coefficient are mainly located in the concave shoreline section. The sampling point of the sediment with great variation of average particle size is mainly located in the reservoir section. However, in the fluvial facies, the sampling points with little change in the mean grain size of the sediment are mostly located in the section where the vegetation growth condition is better, and the variation of the sediment sorting coefficient is relatively small. (3) the results of redundancy analysis show that, The content of heavy gold elements in sediment is relatively small, while the coastline is relatively tortuous, which is favorable to heavy metal elements and organic carbon in sediment of the reach where plant growth is good. The smaller the average grain size of sediment, the better the separation of sediment, and the higher the content of heavy metals in sediment.
【學(xué)位授予單位】：南京大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X143
本文編號：2415874
[Abstract]:A large number of small dams have been built in the Huaihe River basin, where water resources are relatively scarce and the seasonal distribution is uneven, which has changed the river flow pattern and formed a large number of secondary seasonal rivers. In semi-humid and semi-arid areas, the river water is more vulnerable to pollution, especially the heavy metal pollution, which is difficult to transform, because of the relatively small basic flow, which often accumulates in the river and causes ecological harm. Sediment is an important accumulation of heavy metals, organic carbon and other nutrients, and is also the main place for nutrient regeneration. As one of the most important social and economic development areas in China, Huaihe River Basin is also faced with serious sediment pollution. A large number of small dams have been built in the Huaihe River basin, where water resources are relatively scarce and the seasonal distribution is uneven, which has a significant impact on the flow pattern of the river, which has changed the sedimentary environment of the river and created a large number of secondary seasonal rivers. It will also affect the distribution of various heavy metals and nutrient elements such as Nu P in river sediment. In this paper, the Huaihe River, a grade 4 tributary of the Huaihe River, located in Xingyang City, Henan Province, is taken as the research object. The comparison between the measured value and the environmental background value and redundant analysis (mean particle size, sorting coefficient, mean curvature, vegetation biomass) are applied. The distribution characteristics of heavy metal elements, NBP and organic carbon in river sediment were studied by means of environmental impact factors such as coverage and so on. The results are as follows: (1) the contents of elements in sediments of different sampling sites are different, and the enrichment degree of different elements is different. The contents of heavy metals such as Cd,Hg,Zn, N and organic carbon are higher than those of environmental background. The contents of As,Cr,Cu,Mn and other heavy metals were all lower than the environmental background values, and the contents of Cd,Zn and Cd,Zn were higher than those of the first class national standard. The coefficient of variation of organic carbon content is relatively large (0.401-0.550). However, the coefficient of variation of heavy metal elements such as As,Cr,Cu,Pb,Mn,Ni and P was relatively small (0.087-0.215), and its distribution was influenced by the heterogeneity of microhabitat conditions. Habitat heterogeneity affects the enrichment effect of elements in sediment, but the response intensity and response mode of different elements are different to some extent. (2) there are great differences in sediment grain structure among different sections of river. In the reservoir and pond facies, the sampling points with larger average sediment diameter are mainly located in the convex shoreline section, and the sampling points with higher sediment sorting coefficient are mainly located in the concave shoreline section. The sampling point of the sediment with great variation of average particle size is mainly located in the reservoir section. However, in the fluvial facies, the sampling points with little change in the mean grain size of the sediment are mostly located in the section where the vegetation growth condition is better, and the variation of the sediment sorting coefficient is relatively small. (3) the results of redundancy analysis show that, The content of heavy gold elements in sediment is relatively small, while the coastline is relatively tortuous, which is favorable to heavy metal elements and organic carbon in sediment of the reach where plant growth is good. The smaller the average grain size of sediment, the better the separation of sediment, and the higher the content of heavy metals in sediment.
【學(xué)位授予單位】：南京大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X143
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 寧建鳳;鄒獻(xiàn)中;楊少海;陳勇;巫金龍;孫麗麗;;廣東大中型水庫底泥重金屬含量特征及潛在生態(tài)風(fēng)險評價[J];生態(tài)學(xué)報(bào);2009年11期
，本文編號：2415874
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