【摘要】：化學(xué)鈍化和植物吸取技術(shù)作為土壤重金屬污染原位修復(fù)的兩個(gè)重要手段,近年來成為環(huán)境領(lǐng)域的研究熱點(diǎn)。本研究首先對湖南湘潭土壤重金屬修復(fù)基地污染狀況進(jìn)行了初步調(diào)查,然后以不同污染程度酸性農(nóng)田土壤為研究對象,通過連續(xù)多季盆栽試驗(yàn),研究了天然海泡石及石灰鈍化效果及其持效性,并探討了鈍化修復(fù)對后茬吸取修復(fù)植物生長和修復(fù)效率的影響,在此基礎(chǔ)上開展了田間驗(yàn)證試驗(yàn),以探明Cd污染土壤作物-伴礦景天輪作體系下土壤Cd有效性調(diào)控措施。為實(shí)現(xiàn)污染土壤耕作季通過鈍化修復(fù)實(shí)現(xiàn)作物安全生產(chǎn)、休耕季利用吸取修復(fù)實(shí)現(xiàn)污染土壤高效修復(fù)的“邊生產(chǎn)邊修復(fù)”技術(shù)提供理論依據(jù)和技術(shù)支持。主要研究結(jié)果如下：(1)農(nóng)田土壤重金屬污染狀況的調(diào)查表明,研究區(qū)耕層土壤重金屬污染以Cd輕污染為主,平均土壤Cd濃度接近國家土壤環(huán)境質(zhì)量二級標(biāo)準(zhǔn)的2倍。而土壤Pb、Cu和Zn濃度均在二級標(biāo)準(zhǔn)以內(nèi)；從空間分布看,土壤高濃度Cd和Zn點(diǎn)位主要分布在東部、西北和西南邊緣地帶；從垂直分布看,剖面表層土壤Cd、Pb、Zn已明顯累積,但20 cm以下土層土壤幾種重金屬濃度均在二級標(biāo)準(zhǔn)以下。(2)海泡石鈍化修復(fù)盆栽試驗(yàn)結(jié)果顯示,海泡石及石灰對土壤和作物都產(chǎn)生顯著影響。高污染土壤pH值由對照的4.77提高到7.72,土壤Cd有效態(tài)濃度最大降低了85.9%。低污染土壤pH值最大提高了3.57個(gè)pH單位,土壤Cd有效態(tài)濃度最大降低了97.7%;海泡石添加小于2%時(shí),配施石灰效果更明顯；且較長時(shí)間內(nèi),海泡石促進(jìn)小青菜生長和降低其對Cd的吸收。其中低污染土壤,海泡石添加2%及以上,小青菜Cd濃度連續(xù)四季均符合國家食品衛(wèi)生標(biāo)準(zhǔn)。土壤和作物相關(guān)指標(biāo)連續(xù)多季結(jié)果相似,說明鈍化效果能持續(xù)一年或更久。(3)田間條件下鈍化修復(fù)結(jié)果發(fā)現(xiàn),海泡石及石灰對土壤pH值及Cd有效性均有顯著影響。與對照相比,土壤pH提高了0.41-0.86個(gè)pH單位,Cd有效態(tài)濃度降低了37.5%-85.7%,而水稻各時(shí)期根、秸稈、谷殼及糙米Cd濃度有所降低,但無顯著差異。(4)鈍化修復(fù)對后茬吸取修復(fù)植物生長和修復(fù)效率影響結(jié)果表明,適量海泡石對伴礦景天的生長及Cd吸收影響不大,較高劑量添加不利于伴礦景天的吸取修復(fù)。
[Abstract]:Chemical passivation and phytoremediation are two important methods for in situ remediation of heavy metal pollution in soil. In recent years, chemical passivation and phytoremediation have become the research focus in the field of environment. In this study, the pollution status of heavy metal remediation base in Xiangtan soil in Hunan Province was investigated, and then the acid farmland soil with different levels of pollution was used as the research object, and the pot experiment was carried out in succession of seasons. The passivation effect of natural sepiolite and lime and its persistence were studied. The effects of passivation and restoration on the growth and restoration efficiency of subsequent stubble remediation plants were discussed. Based on this, field validation experiments were carried out. The effective control measures of soil Cd under the rotation system of Cd contaminated soil crop and Jinjingtian were investigated. In order to realize the safe production of crops by passivation remediation in tillage season of contaminated soil, and to provide theoretical basis and technical support for the technology of "remediation while production while repairing" in fallow season, which can be used to achieve efficient remediation of contaminated soil by absorption remediation in fallow season. The main results are as follows: (1) the investigation of heavy metal pollution in farmland soil showed that the heavy metal pollution in the cultivated layer was mainly caused by Cd light pollution, and the average Cd concentration was close to 2 times of the national second grade standard for soil environmental quality. The concentration of Pb,Cu and Zn in soil was within the second grade standard, and the spatial distribution of high concentration Cd and Zn in soil was mainly in the eastern, northwest and southwest marginal areas. From the vertical distribution, Cd,Pb,Zn accumulated obviously in the surface soil of the profile, but the concentrations of several heavy metals in the soil layer below 20 cm were below the second grade standard. (2) the results of pot experiment of sepiolite passivation restoration showed that Sepiolite and lime have significant effects on soil and crops. The pH value of highly polluted soil increased from 4.77 to 7.72, and the available concentration of Cd decreased by 85.9%. The maximum pH value of low-polluted soil increased 3.57 pH units, and the maximum effective concentration of Cd decreased 97.70.When sepiolite was added less than 2, the effect of lime application was more obvious. For a long time, sepiolite promoted the growth and decreased the absorption of Cd. The low pollution soil, sepiolite added 2% and above, the Cd concentration of small green vegetables all accord with the national food hygiene standard for four consecutive seasons. Soil and crop related indexes were similar in successive seasons, indicating that the passivation effect could last for one year or longer. (3) the results of passivation and remediation under field conditions showed that sepiolite and lime had significant effects on soil pH value and Cd availability. Compared with the control, soil pH increased 0.41-0.86 pH units, Cd effective state concentration decreased 37.5% and 85.75.75%, while the Cd concentration of rice root, straw, husk and brown rice decreased. But there was no significant difference. (4) the effects of passivation and restoration on the growth and restoration efficiency of the plant showed that the proper amount of sepiolite had little effect on the growth and Cd absorption of Sedum. Higher dose addition is unfavorable to the drainage and restoration of Sedum.
【學(xué)位授予單位】：湖南師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X53

【參考文獻(xiàn)】

相關(guān)期刊論文 前2條

1 孫約兵;徐應(yīng)明;史新;王林;梁學(xué)峰;;海泡石對鎘污染紅壤的鈍化修復(fù)效應(yīng)研究[J];環(huán)境科學(xué)學(xué)報(bào);2012年06期

2 王林;徐應(yīng)明;梁學(xué)峰;孫國紅;孫約兵;林大松;;廣西刁江流域Cd和Pb復(fù)合污染稻田土壤的鈍化修復(fù)[J];生態(tài)與農(nóng)村環(huán)境學(xué)報(bào);2012年05期

，

本文編號(hào)：2393678