本文關(guān)鍵詞： 農(nóng)田土壤 重金屬 空間變異 來(lái)源解析 生態(tài)效應(yīng) 風(fēng)險(xiǎn)評(píng)價(jià)　出處：《南京信息工程大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：我們國(guó)家之前的土壤地球化學(xué)調(diào)查及部分人的研究已經(jīng)發(fā)現(xiàn)南京沿江地區(qū)普遍存在土壤Cd等重金屬含量異�，F(xiàn)象,但目前對(duì)這些重金屬異常的成因、生態(tài)效應(yīng)及對(duì)人體的健康風(fēng)險(xiǎn)還沒(méi)有明確的結(jié)論。因此,開展“南京沿江地區(qū)重金屬多介質(zhì)富集特征、來(lái)源及生態(tài)效應(yīng)”的研究具有重要的土壤環(huán)境地球化學(xué)理論意義,同時(shí)對(duì)土壤重金屬污染的風(fēng)險(xiǎn)評(píng)估與環(huán)境管理也具有重要的參考價(jià)值。本文選取南京沿江地區(qū)為研究對(duì)象,通過(guò)測(cè)定并分析表層土壤和沉積物、剖面土壤和沉積物、植物、肥料及大氣降塵中重金屬含量和同位素比值,揭示了土壤和沉積物重金屬異常的空間變異特征；利用多元統(tǒng)計(jì)分析、正定矩陣因子分析法(PMF)探究典型農(nóng)業(yè)區(qū)表層土壤重金屬主要來(lái)源,并與Pb穩(wěn)定同位素比值結(jié)果進(jìn)行對(duì)比分析；運(yùn)用地積累指數(shù)法、人體健康風(fēng)險(xiǎn)評(píng)價(jià)法對(duì)土壤、沉積物和作物重金屬富集進(jìn)行生態(tài)效應(yīng)和人體攝入風(fēng)險(xiǎn)評(píng)價(jià)。結(jié)果表明：(1)研究區(qū)表層土壤鎘(Cd)、砷(As)、汞(Hg)、鉛(Pb)、銅(Cu)、鋅(Zn)和鉻(Cr)平均含量均高于南京市土壤背景值,部分樣點(diǎn)土壤Cd、Hg和Cu含量超過(guò)了國(guó)家土壤環(huán)境質(zhì)量標(biāo)準(zhǔn)的二級(jí)標(biāo)準(zhǔn),在土壤中呈現(xiàn)較高的累積；表層沉積物中Cd、As、Hg, Pb、Cu、Zn和Cd的平均含量分別為0.65、15.8、0.13、42.1、45.8、124和85.3mg/kg、其中As、Pb, Cu、Zn和Cr平均含量超過(guò)美國(guó)EPA標(biāo)準(zhǔn)。南京沿江流域土壤重金屬人為活動(dòng)系數(shù)(AF)略低于富集系數(shù)(EF),沉積物重金屬AF明顯低于EF。(2)根莖中Cd和Pb的含量分別為0.15和0.13mg/kg,水稻中Pb和Cr的含量分別為1.07和6.95mg/kg,葉菜和小麥中Cr的含量分別為0.78和1.39mg/kg,均超過(guò)我國(guó)食品中污染物限量標(biāo)準(zhǔn)(GB 2762-2012)。根莖類蔬菜中Cd、Pb和Zn的含量高于茄果類和葉菜類,As、Hg、Cu和Cd在葉菜類中含量高于茄果類和根莖類。(3)南京沿江八卦洲農(nóng)業(yè)區(qū)及沿江工業(yè)區(qū)附近重金屬含量普遍偏高,八卦洲農(nóng)業(yè)區(qū)內(nèi)除Cr以外,其他表層土壤重金屬均呈現(xiàn)東南偏高西北偏低的空間分布特征,與土壤有機(jī)質(zhì)的空間分布規(guī)律一致。南京沿江流域上游至下游,沉積物中重金屬含量總體呈現(xiàn)增加趨勢(shì),且在南京八卦洲農(nóng)業(yè)區(qū)及沿江工業(yè)區(qū),沉積物重金屬含量明顯高于其它區(qū)域,八卦洲農(nóng)業(yè)區(qū)周邊沉積物剖面中的重金屬含量普遍偏高,且底層沉積物依然具有較高的重金屬含量。(4)通過(guò)PMF模型得出四個(gè)污染源：農(nóng)業(yè)源、降塵源、工業(yè)源和自然源,貢獻(xiàn)率分別為30.8%,33.0%,25.4%和10.8%,Pb穩(wěn)定同位素比值法計(jì)算大氣降塵對(duì)土壤Pb累積的貢獻(xiàn)率分別為36.8%,與PMF模型計(jì)算結(jié)果相似。土壤重金屬累積和分布狀況與研究區(qū)的地形、周邊工農(nóng)業(yè)布局、風(fēng)向、交通污染和自然母質(zhì)有關(guān)。(5)工業(yè)區(qū)沉積物Cd的地累積指數(shù)為0.04,達(dá)到輕度-中等污染,點(diǎn)位污染率為23.0%。Cd和Hg單項(xiàng)污染潛在生態(tài)風(fēng)險(xiǎn)在土壤和沉積物為中等生態(tài)危險(xiǎn),水稻中攝入重金屬的健康風(fēng)險(xiǎn)明顯高于蔬菜和其他作物。
[Abstract]:Soil geochemical investigation and some studies in our country have found that CD and other heavy metals are abnormal in soils along the Yangtze River in Nanjing, but at present, the causes of these anomalies are discussed. There is no clear conclusion on ecological effect and health risk to human body. Therefore, the enrichment characteristics of heavy metals in the Yangtze River area along the Nanjing River have been carried out. The study of source and ecological effects has important theoretical significance in soil environmental geochemistry. At the same time, it has important reference value for risk assessment and environmental management of soil heavy metal pollution. The heavy metal contents and isotopic ratios in soil and sediment, plants, fertilizers and atmospheric dust fall reveal the spatial variation characteristics of heavy metal anomalies in soil and sediment. Using multivariate statistical analysis and positive definite matrix factor analysis (PMF), the main sources of heavy metals in topsoil of typical agricultural areas were explored, and the results were compared with the results of Pb stable isotopic ratios. The ecological effects and intake risk of heavy metals in soil, sediment and crops were evaluated by the method of land accumulation index and human health risk assessment. The results showed that CD ~ (2 +) + CD ~ (2 +) in the surface soil of the study area was 1). The average contents of as, Hg, Pb, Cu, Zn (Zn) and Cr (Cr) were higher than those in Nanjing, and CD in some soil samples were higher than those in Nanjing. The content of Hg and Cu exceeded the second grade standard of national soil environmental quality standard, and showed a high accumulation in soil. The average contents of CD ~ (2 +) ~ (2 +) ~ (2 +) ~ (2 +) ~ (2 +) in the surface sediments are 0.65 ~ (15. 8) ~ (0.13) ~ 42.1 ~ (-1) ~ 45.8, respectively. 124 mg / kg and 85.3 mg / kg, in which Aso Pb, Cu. The average content of Zn and Cr is higher than the EPA standard of the United States, and the anthropogenic activity coefficient of heavy metals in the soil of Nanjing River Basin is slightly lower than that of the enrichment factor (EFF). The contents of CD and Pb in the rhizome of the sediment were 0.15 and 0.13 mg / kg, respectively. The contents of Pb and Cr in rice were 1.07 and 6.95 mg / kg, and the contents of Cr in leaf vegetables and wheat were 0.78 and 1.39 mg / kg, respectively. The contents of CD ~ (2 +) Pb and Zn in rhizomatous vegetables were higher than those in eggplant and leaf vegetables. The contents of Cu and CD in leafy vegetables are higher than those in eggplant and rhizome.) the heavy metal content in the agricultural area of Bagua Island along the Yangtze River and near the industrial area along the Yangtze River is generally high, except Cr in the agricultural area of Baguazhou. The distribution of heavy metals in other surface soils was similar to that of soil organic matter in the upper reaches to the lower reaches of the Yangtze River basin, and the spatial distribution of heavy metals in the topsoil was higher than that in the southeast and lower in the northwest. The content of heavy metals in sediments showed an increasing trend, and in the agricultural area of Baguazhou in Nanjing and the industrial area along the Yangtze River, the heavy metal content in sediment was obviously higher than that in other regions. The content of heavy metals in the sediment profile around the agricultural area of Bagua Island is generally high, and the bottom sediment still has high heavy metal content.) through the PMF model, four sources of pollution are obtained: agricultural source, dust source. The contribution rates of industrial and natural sources were 30.8% and 10.8% respectively. The contribution rate of atmospheric dust to soil Pb accumulation calculated by Pb stable isotope ratio method is 36.8, which is similar to that of PMF model. The accumulation and distribution of heavy metals in soil and the topography of the study area. Industrial and agricultural distribution, wind direction, traffic pollution and natural parent material.) the accumulation index of CD in the sediments of industrial area is 0.04, which reaches mildly to moderate pollution. The potential ecological risk of single pollution was 23.0. CD and Hg in soil and sediment. The health risk of heavy metal intake in rice was significantly higher than that in vegetables and other crops.
【學(xué)位授予單位】：南京信息工程大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X53

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