本文選題：西遼河　切入點：沉積物　出處：《吉林農(nóng)業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：重金屬Pb的遷移轉(zhuǎn)化是以泥沙顆粒為主要載體,河流輸送主要以顆粒態(tài)鉛為主。為估算隨泥沙遷移的顆粒態(tài)Pb的質(zhì)量分?jǐn)?shù)與不同粒級沉積物吸附態(tài)鉛對上覆水體的釋放通量,采用吸附平衡法、解吸平衡法進(jìn)行室內(nèi)試驗,進(jìn)而為顆粒態(tài)鉛的質(zhì)量分?jǐn)?shù)與吸附態(tài)鉛的釋放通量的估算提供理論依據(jù)。不同粒級沉積物對Pb的吸附特征均符合Langmuir吸附等溫式。對重金屬Pb的富集系數(shù)分別為黏粒為1.66、粉粒為1.48、細(xì)砂為0.85、粗砂為0.48。黏粒和粉粒的鉛富集系數(shù)分別是粗砂的3.46和3.08倍,富集水平均為低度富集。粗砂和細(xì)砂級沉積物對重金屬Pb沒有富集作用。河流中細(xì)粒級沉積物中腐殖質(zhì)含量要比粗粒級沉積物中腐殖質(zhì)含量要高,穩(wěn)結(jié)態(tài)腐殖質(zhì)在細(xì)粒級的沉積物中所占的比例與其他粒級相比較則更明顯。不同形態(tài)腐殖質(zhì)含量對Pb的富集系數(shù)影響程度順序為穩(wěn)結(jié)態(tài)腐殖質(zhì)(r為0.981)、緊結(jié)態(tài)腐殖質(zhì)(r為0.951)、松結(jié)態(tài)腐殖質(zhì)(r為0.832)。不同粒級沉積物對鉛的富集系數(shù)與腐殖質(zhì)總量呈顯著正相關(guān)(p0.01),相關(guān)系數(shù)(r)為0.964;在西遼河汛期,重金屬鉛以黏粒級沖瀉泥沙為載體隨河水遷移其質(zhì)量分?jǐn)?shù)按照106.02 mg/kg估算,粉粒級可按98.71mg/kg估算。不同粒級沉積物對Pb的吸附特征均符合Langmuir吸附等溫式。粗砂、細(xì)砂、粉粒、黏粒鉛解吸比例(Dr)依次為:28.85%、15%、0.68%、0.65%;其解吸遲滯性指數(shù)(TⅡ)依次為:0.08、0.34、0.53、0.59。粗砂粒級,解吸比例(Dr),明顯高于細(xì)粒級,而解吸遲滯性指數(shù)(TⅡ),明顯低于其他粒級;西遼河不同粒級沉積物吸附態(tài)鉛的釋放通量為粗砂為22.42mg/kg、細(xì)砂為11.83mg/kg、粉粒為0.61mg/kg、黏粒為0.67mg/kg。盡管粗砂粒級對于鉛的吸附量較低(77.31mg/kg),但粗砂粒級對于鉛的解吸比例較高(28.85%)。致使粗砂粒級吸附態(tài)鉛的釋放通量較大(22.30mg/kg)。吸附在黏粒與粉粒兩個粒度的重金屬鉛是地球化學(xué)循環(huán)過程中不可或缺的一部分。
[Abstract]:In order to estimate the mass fraction of particulate Pb and the flux of adsorbed lead to overlying water, the transport of heavy metal Pb is mainly carried by sediment particles. The adsorption equilibrium method and desorption equilibrium method were used for laboratory test. It provides theoretical basis for the estimation of mass fraction of granular lead and flux of adsorbed lead. The adsorption characteristics of Pb in different granular sediments are in accordance with the Langmuir adsorption isotherm. The enrichment coefficient of Pb for heavy metal is viscosity, respectively. The lead enrichment coefficients of clay and silt are 3.46 and 3.08 times of coarse sand, respectively, and 1.66 of silt, 0.85 of fine sand, 0.48 of coarse sand, 1.66 of silt, 0.85 of fine sand and 0.48 of coarse sand, respectively. The enrichment level was low. Coarse sand and fine sand sediment had no enrichment effect on heavy metal Pb. The humus content in fine grain sediment in river was higher than that in coarse grain sediment, and the content of humus in fine grain sediment was higher than that in coarse grain sediment, and the content of humus in fine grain sediment was higher than that in coarse grain sediment. The proportion of stable humus in fine-grained sediment was more obvious than that in other grain-grade sediments. The order of influence of different humus content on Pb enrichment coefficient was as follows: stable humus content r = 0.981g, compact humus content = 0.981g. The content of lead in different grain sediments was positively correlated with the total amount of humus, and the correlation coefficient (r) was 0.964.In the flood season of West Liaohe River, there was a significant positive correlation between the enrichment coefficient of lead and the total amount of humus, and the correlation coefficient (r) was 0.964.In the flood season of the West Liaohe River, there was a significant positive correlation between the enrichment coefficient of lead and the total amount of humus. The mass fraction of heavy metal lead is estimated according to 106.02 mg/kg and 98.71 mg / kg with the transport of clay grade sediment. The adsorption characteristics of Pb on different grained sediments are in accordance with the Langmuir adsorption isotherm, coarse sand, fine sand, silt, fine sand, silt, fine sand, silt, coarse sand, fine sand, silt, fine sand, fine sand and silt, The viscosity lead desorption ratio (Dr) was: 1: 28.85 / 150.68 and 0.65, respectively; the desorption hysteresis index (TII) was 0. 088 / 0.34 + 0. 53- 0. 59.The desorption ratio of coarse sand was significantly higher than that of fine grain, while the desorption hysteresis index (T 鈪，

本文編號：1632417