干湿交替过程锑矿土壤中As、Sb及氧化铁变化研究

发布时间：2018-03-22 00:12

  本文选题：砷　切入点：锑　出处：《贵州大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文以黔西南州晴隆锑矿周边土壤为研究对象,采集21个表层土壤样品,分析测定了As和Sb的含量、赋存形态及生物有效性。以贵州省土壤背景值和国家土壤环境质量标准为依据,利用单因子污染指数法评价了土壤As和Sb的污染特征,并借助Hakanson潜在生态危害指数法评价As、Sb污染程度及环境风险。采用实地调查和模拟试验相结合的研究方法,在实验室模拟研究干湿条件下土壤As、Sb及氧化铁的变化特征。土壤样品As和Sb含量分析采用微波消解-氢化物发生-原子荧光光谱法,As和Sb形态特征分析使用“土壤和沉积物13个微量元素形态顺序提取程序”国家标准方法(GB/T25282-2010)。结果表明:(1)研究区土壤As、Sb污染严重,尤以Sb更甚。土壤As含量范围在12.38-127.85 mg·kg-1,高于背景值0.61-6.39倍;土壤As的均值为43.52 mg·kg-1,高于国家土壤环境质量二级标准30 mg·kg-1,超过贵州省土壤背景值20 mg·kg-1。土壤Sb含量范围在171.9-603.8 mg·kg-1,高于背景值76.75-269.54倍;均值为267.5 mg·kg-1,高于背景值119.42倍。经单因子污染指数分析,As和Sb单项污染指数Pi范围分别为:Pi(As)0.62-6.39,Pi(Sb)76.8-269.5,As属中度污染和轻度污染,而Sb属于重度污染,土壤的污染程度SbAs。经Hakanson潜在生态风险评价,研究区重金属的总潜在生态风险值很高,33.33%的土壤样品生态风险很强,67.67%的土壤样品生态风险极强,即生态危害程度总体为强;从单元素角度分析可知:Sb的潜在生态危害程度高于As。(2)研究区土壤As和Sb的存在形态均以残渣态为主,分别占总量的52.87%-87.58%、76.30%-91.47%。其次是可还原态和可氧化态,弱酸提取态含量较低,水溶态含量最低。土壤中As的可还原态、可氧化态、弱酸提取态、水溶态分别占总量的2.49%-19.59%、3.68%-20.46%、0.16%-3.86%和0.02%-0.77%;土壤中Sb的可还原态、可氧化态、弱酸提取态、水溶态分别占总量的0.58%-7.16%、0.77%-7.34%、0.05%-1.51%和0.01%-1.10%。经相关性分析,土壤As不同形态之间、Sb不同形态之间、甚至As和Sb部分形态之间均呈显著的线性相关关系。经初步分析,土壤中生物可利用态锑含量为0.15-14.60 mg·kg-1,占总量的0.05%-2.46%,而土壤中生物可利用态砷含量为0.12-2.94 mg·kg-1,占总量的0.21%-4.37%。(3)持续淹水期间,水溶液中As、Sb含量都随淹水天数递增而呈先快速增加后保持平稳的趋势,水溶液中三价砷占总砷及三价锑占总锑的比例亦呈相同变化趋势。淹水后,污染程度不同的3种处理土壤(TH-CF、TM-CF、TL-CF)Sb的水溶态、弱酸提取态、可还原态和可氧化态的比重都增加了,残渣态Sb的比重降低了;土壤As各形态(水溶态、弱酸提取态、可还原态、可氧化态和残渣态)的比重有增有减,且增减幅度有所不同。持续淹水期间,土壤As不同形态之间、土壤Sb不同形态之间都存在显著的线性相关关系。(4)持续淹水期间,土壤无定形氧化铁的含量随着淹水时间的延长而增加,土壤结晶态氧化铁含量则随淹水时间的延长而减少。在污染程度不同的3种处理(TH-CF、TM-CF、TL-CF)土壤中,土壤无定形氧化铁含量具有相同的变化趋势,淹水84 d后分别较淹水前增加了133.42%、137.79%、326.5%;土壤氧化铁活化度亦随着淹水时间的延长而增大,变化趋势基本相同,但TL-CF土壤中活化度增幅最明显。持续淹水期间,土壤结晶态氧化铁含量逐渐减少,淹水初期(0-7 d)的变化最为剧烈,到淹水末期(84 d),3种处理(TH-CF、TM-CF、TL-CF)土壤结晶态氧化铁含量降幅分别为36.46%、43.57%、51.89%。(5)干湿交替过程中,土壤Sb和As各形态含量都随周期性干湿交替而呈波动变化,土壤不同形态As(Ⅲ)及Sb(Ⅲ)含量也随着周期性干湿交替呈波动变化。污染程度不同的3种处理土壤(TH-DW、TM-DW、TL-DW),淹水时,除残渣态外,土壤中其它形态的As和Sb含量都随淹水天数递增而递减,递减幅度大小为:水溶态弱酸提取态可还原态和可氧化态;落干时,土壤As和Sb各形态的含量呈波动变化,水溶态、弱酸提取态微减,残渣态微增,可还原态和可氧化态有增有减,但各形态之和基本相等。污染程度不同的3种处理土壤(TH-DW、TM-DW、TL-DW),淹水时,土壤As(Ⅲ)及Sb(Ⅲ)含量增加,As(Ⅲ)及Sb(Ⅲ)占各自总的比例也增加;落干时,土壤As(Ⅲ)及Sb(Ⅲ)含量略微减小,As(Ⅲ)及Sb(Ⅲ)占各自总的比例也略微减小。干湿交替过程中,土壤As不同形态之间、土壤Sb不同形态之间均存在显著的线性相关关系。(6)干湿交替过程中,土壤无定形氧化铁和结晶态氧化铁的含量都随周期性干湿交替而呈波动变化,且各自变化趋势基本相同。污染程度不同的3种处理土壤(TH-DW、TM-DW、TL-DW),淹水时,土壤无定形氧化铁含量增加,土壤结晶态氧化铁含量减少;落干时,土壤无定形氧化铁含量减少,土壤中结晶态氧化铁含量增加,但增减幅度各略有不同。
[Abstract]:This paper takes Qianxi Prefecture in Qinglong antimony mine surrounding soil as the research object, collected 21 surface soil samples, the contents of As and Sb were analysed, speciation and bioavailability. The background values of soils in Guizhou province and the state soil environment quality standard as the basis, using the method of single factor pollution index to evaluate the soil pollution of As and Sb and with the help of the Hakanson potential ecological risk index method in the evaluation of As, Sb pollution and environmental risk. Adopting the research method of field investigation and simulation test of the combination, in the laboratory simulation of soil As, Sb variation and oxidation of iron. By microwave digestion hydride generation atomic fluorescence spectrometry analysis of soil samples As and the content of Sb, As and Sb analysis of morphological characteristics using the "program" national standard method for extraction of soil and sediment of 13 trace elements form sequence (GB/T25282-2010). The results showed that: (1). The study area of soil As, Sb pollution is serious, especially Sb. Soil As content in the range of 12.38-127.85 mg, kg-1, 0.61-6.39 times higher than the background value; the mean soil As was 43.52 mg kg-1, higher than the two level of the national soil environmental quality standard of 30 mg / kg-1, exceed the background values of soils in Guizhou province 20 mg kg-1. the content of soil Sb in the range of 171.9-603.8 mg, kg-1, 76.75-269.54 times higher than the background value; the mean value of 267.5 Mg - kg-1, 119.42 times higher than the background value. By the analysis of single factor pollution index, As and Sb single pollution index of Pi were Pi (As) 0.62-6.39, Pi (Sb) 76.8-269.5, As and moderate pollution light pollution, and Sb pollution is severe, the soil pollution degree of SbAs. by Hakanson potential ecological risk assessment, the total potential ecological risk of heavy metals in value is very high, the ecological risk of 33.33% soil samples is very strong, the ecological risk of 67.67% soil samples is extremely strong, namely ecological hazard The overall degree is strong; the analysis from the angle of single element: the degree of potential ecological risk of Sb is higher than As. (2) forms of soil As and Sb were mainly in residual form, accounting for the total 52.87%-87.58%, 76.30%-91.47%. followed by the reducible and oxidizable state, weak acid extraction low content water the lowest content of soluble As in the soil. The reducible, oxidizable, acid extractable state, water soluble and accounted for 2.49%-19.59%, 3.68%-20.46%, 0.16%-3.86% and 0.02%-0.77%; Sb in soil reducible, oxidizable, acid extractable state, water soluble and accounted for 0.58%-7.16%, 0.77%-7.34%, 0.05%-1.51% 0.01%-1.10%. and the correlation analysis between soil As of different forms, between different forms of Sb, and showed a significant linear relationship between As and Sb form. After preliminary analysis, bio available in soil by state of antimony content was 0.15-14.60 mg Kg-1, accounting for 0.05%-2.46% of the total, while soil bioavailable arsenic content is 0.12-2.94 mg kg-1, accounting for 0.21%-4.37%. of the total (3) sustained during the flooding in aqueous solution As, Sb content with the increasing number of water flooded and has maintained a steady trend after the first rapid increase, water soluble trivalent arsenic solution the total arsenic and trivalent antimony accounted for the proportion of antimony was also the same trend. After flooding, 3 kinds of soil with different pollution levels (TH-CF, TM-CF, TL-CF) Sb water soluble, acid extractable, reducible and oxidizable proportion has increased, the proportion of reducing residual Sb; various forms of soil As (water soluble, acid extractable, reducible, oxidizable and residual) proportion increases and decreases, and the changes are different. The continuous flooding period, soil As of different forms of soil, Sb there is a significant linear relationship between different forms (4. Continuous flooding) During the period, the content of soil amorphous iron oxides increased with the flooding time, soil crystalline iron oxide content decreased with prolonged inundation. In 3 kinds of different pollution levels (TH-CF, TM-CF, TL-CF) in soil, soil amorphous iron oxide containing gauge has the same change trend, flooding after 84 D compared with before flooding increased by 133.42%, 137.79%, 326.5%; the activation degree of soil iron oxide with prolonged inundation and the increasing trend is basically the same, but the TL-CF in soil salinity increase. Live the most obvious sustained during the flooding of the soil crystalline iron oxide content decreased gradually, and waterlogging (0-7 d) was the most severe changes to the end, flooding (84 d), 3 (TH-CF, TM-CF, TL-CF treatment) by soil crystallization ferric oxide content were 36.46%, 43.57%, 51.89%. (5) alternate process, various forms of soil Sb and As content with periodic 骞叉箍浜ゆ浛鑰屽憟娉㈠姩鍙樺寲,鍦熷￥涓嶅悓褰㈡，

本文编号：1646185