發(fā)布時(shí)間：2018-04-27 10:05

  本文選題：呼和浩特市 + 道路��； 參考：《內(nèi)蒙古師范大學(xué)》2015年碩士論文

【摘要】：作為城市生態(tài)系統(tǒng)重要組成部分之一的城市土壤,不但能夠?qū)ξ廴疚镔|(zhì)進(jìn)行容納緩沖和凈化,還可能經(jīng)過(guò)生態(tài)系統(tǒng)將污染物尤其是重金屬污染物作用于人類(lèi)自身。隨著城市人口的增加,工業(yè)的發(fā)展,機(jī)動(dòng)車(chē)輛也會(huì)隨之增加,重金屬對(duì)人體危害的強(qiáng)度也在增加。所以,在城市化進(jìn)程中深入研究城市道路土壤重金屬元素積累情況并對(duì)其進(jìn)行評(píng)價(jià)是非常必要的。本文對(duì)呼和浩特市城市發(fā)展進(jìn)程中道路土壤的重金屬積累問(wèn)題進(jìn)行研究,采用多因素綜合評(píng)定法,綜合分析影響呼和浩特市道路土壤環(huán)境質(zhì)量。首先,按照道路等級(jí)不同對(duì)城市土壤進(jìn)行分區(qū)采樣,測(cè)定土壤p H值、有機(jī)質(zhì)含量、重金屬F e、P b、Cu、Mn、Cr的含量,共計(jì)130個(gè)樣品。測(cè)定表明,通車(chē)時(shí)間越長(zhǎng)、車(chē)流量越大,道路表層重金屬含量累積量越大,道路重金屬含量高速路國(guó)道省道鄉(xiāng)間路,除鄉(xiāng)間路Cu、Mn、Cr元素外,其余道路土壤重金屬元素平均含量均超過(guò)內(nèi)蒙古自治區(qū)土壤背景值,道路表層土壤重金屬F e、P b、Cu、Mn、Cr含量分別為內(nèi)蒙古自治區(qū)土壤背景值的1.49倍、2.74倍、1.39倍、1.22倍和1.43倍;研究表明道路土壤表層重金屬含量在道路邊含量達(dá)到最大,然后隨距離的增加下降,在3 0~50m附近達(dá)到第二個(gè)峰值,后又逐步下降接近土壤背景值。路旁土壤重金屬含量的峰值出現(xiàn)在離開(kāi)路基一定距離處的原因,可能是由于車(chē)輛快速行駛導(dǎo)致路基附近出現(xiàn)湍流所致。而離開(kāi)路基一段距離后,湍流消失利于顆粒物沉降,從而造成路旁土壤重金屬在道路旁呈偏態(tài)分布;其次,對(duì)高速路上風(fēng)、下風(fēng)側(cè)土壤進(jìn)行配對(duì)樣品均值和T檢驗(yàn),統(tǒng)計(jì)表明:峰值濃度出現(xiàn)的位置相較于下風(fēng)向更接近道路。另外,車(chē)輛類(lèi)型、運(yùn)載貨物的不同也會(huì)影響道路土壤中重金屬元素P b、C u累積量的差異。通過(guò)相關(guān)分析,重金屬元素F e、P b、Mn、Cr之間存在較強(qiáng)的相關(guān)性,可能具有相同的來(lái)源。Cu與其他元素之間的相關(guān)系數(shù)小于0.6,為中等程度相關(guān)。經(jīng)過(guò)聚類(lèi)分析和主成分分析,識(shí)別道路沉積物中重金屬的來(lái)源,將5種重金屬元素辨識(shí)為2個(gè)主成分,第一主成分(貢獻(xiàn)率7 0%以上)主要為交通活動(dòng)產(chǎn)生的污染源,包括F e、P b、Cr、Mn元素,第二主成分Cu元素為“自然源因子”;最后,根據(jù)國(guó)家土壤環(huán)境質(zhì)量標(biāo)準(zhǔn)二級(jí)標(biāo)準(zhǔn)(GB1561 8-199 5)計(jì)算了呼和浩特市道路兩側(cè)土壤重金屬累積程度(高速路國(guó)道省道鄉(xiāng)間路),潛在生態(tài)危害綜合數(shù):RI=∑Er i=1.77,表明呼和浩特市道路周邊表層土壤重金屬Cu、Cr、P b環(huán)境整體良好,五種重金屬元素的累積程度明顯低于東京、廣州等發(fā)達(dá)城市,這可能與近幾年呼和浩特市道路周邊加強(qiáng)生態(tài)建設(shè)以及城市發(fā)展歷史較短密切相關(guān)。
[Abstract]:As one of the important parts of urban ecosystem, urban soil can not only absorb and purify the pollutants, but also affect the pollutants, especially heavy metal pollutants, through the ecosystem. With the increase of urban population and the development of industry, motor vehicles will also increase, and the intensity of heavy metal harm to human body will also increase. Therefore, it is necessary to study and evaluate the accumulation of heavy metals in urban road soil in the process of urbanization. In this paper, the accumulation of heavy metals in the road soil in the course of urban development in Hohhot was studied. The comprehensive evaluation method was used to analyze comprehensively the environmental quality of the road soil in Hohhot. Firstly, according to the different road grade, the soil pH value, the content of organic matter and the content of heavy metal, Fe, Pb, Cu, mn, Cr in urban soil were measured, and a total of 130 samples were collected. The results show that the longer the opening time, the greater the traffic flow, the greater the accumulation of heavy metals in the surface layer of the road, the higher the heavy metal content of the road, the higher the heavy metal content of the road, the higher the content of heavy metal in the highway, the more the provincial road, the rural road, except for the element of Cufen Mn@@ The average content of heavy metal elements in other road soils was higher than the soil background values of Inner Mongolia Autonomous region, and the content of heavy metals in the surface soils was 1.49 times, 2.74 times, 1.39 times, 1.22 times and 1.43 times of the soil background values of Inner Mongolia, respectively. The results showed that the content of heavy metals in the surface layer of road soil reached the maximum at the edge of the road, then decreased with the increase of the distance, reached the second peak value at the distance of 30 ~ 50m, and then gradually decreased to the soil background value. The peak value of heavy metal content in the roadside soil appears at a certain distance from the roadbed, which may be due to the turbulence near the roadbed caused by the rapid driving of the vehicle. After a distance away from the roadbed, the turbulence disappear is beneficial to the settling of particulate matter, which results in the distribution of heavy metals in the roadside soil. Secondly, the mean value and T test of the matched samples are carried out on the wind and downwind side of the highway. Statistics show that the location of peak concentration is closer to the road than the downwind direction. In addition, the type of vehicle and the different cargoes can also affect the accumulation of heavy metals in road soil. According to the correlation analysis, there is a strong correlation between heavy metal element, Fe, P, B, mn, Cr, and the correlation coefficient between the same source, Cu and other elements is less than 0.6, which is moderate. Through cluster analysis and principal component analysis, the sources of heavy metals in road sediments were identified. The five heavy metals were identified as two principal components. The first principal component (contribution rate of more than 70%) was mainly the source of pollution caused by traffic activities. The second principal component Cu is "natural source factor". According to the second grade standard of national soil environmental quality standard (GB1561 8-1995), the accumulation degree of heavy metals on both sides of the road in Hohhot city is calculated (the comprehensive number of potential ecological hazards is: Ri = 鈭，

本文編號(hào)：1810288