本文關(guān)鍵詞：組配改良劑對稻田鎘砷復(fù)合污染的調(diào)控效果及機(jī)制研究　出處：《中南林業(yè)科技大學(xué)》2017年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 鎘 砷 組配改良劑 水稻 生物有效性

【摘要】：伴隨我國工農(nóng)業(yè)的快速發(fā)展,我國耕地受Cd和As等重金屬污染的問題日益嚴(yán)重。湖南省是有色金屬之鄉(xiāng)和魚米之鄉(xiāng),規(guī)�；V業(yè)開采與冶煉對礦區(qū)生態(tài)環(huán)境及農(nóng)業(yè)生產(chǎn)帶來了嚴(yán)重破壞,嚴(yán)重地制約著湖南省廣大地區(qū)水稻生產(chǎn)安全和稻米食用安全。如何治理Cd和As復(fù)合污染農(nóng)田,如何控制Cd和As向水稻中轉(zhuǎn)移是一個(gè)亟待解決的環(huán)境問題。本研究圍繞稻田土壤Cd和As復(fù)合污染的修復(fù),以郴州柿竹園礦區(qū)(A礦區(qū))及湘西州保靖縣復(fù)興村礦區(qū)(B礦區(qū))不同Cd和As污染程度的稻田土壤為研究對象,通過改良劑篩選實(shí)驗(yàn)、水溶液吸附實(shí)驗(yàn)、水稻盆栽實(shí)驗(yàn)以及大田實(shí)驗(yàn)等研究,研發(fā)了一種組配改良劑QFJ,系統(tǒng)闡述了應(yīng)用QFJ降低土壤Cd、As生物有效性和糙米Cd、As含量的機(jī)制,提出了一套控制稻田Cd和As生物有效性和遷移轉(zhuǎn)運(yùn)的有效技術(shù)。研究結(jié)果如下:(1)研制出以羥基磷灰石、沸石和改性秸稈炭3種物質(zhì)為主要成分,按一定質(zhì)量比例組配的改良劑QFJ,確定其作用機(jī)制:3種物質(zhì)具有較大的比表面積,可與溶液中Cd2+和As5+發(fā)生表面吸附和孔道吸附,QFJ含有的-OH、-COOH、-Si-O-Si以及C032-基團(tuán)與溶液中Cd2+、As5+離子發(fā)生了交換吸附、共價(jià)結(jié)合,生成了羧酸鹽類、硅酸鹽類和碳酸鹽類物質(zhì),從而將土壤溶液中游離的Cd2+、As3+和As5+原位鈍化。(2)施用組配改良劑QFJ改良Cd和As復(fù)合污染稻田土壤,水稻盆栽實(shí)驗(yàn)顯示:根際土壤pH值、CEC和OM含量呈現(xiàn)上升趨勢。QFJ的施用使得水稻黃華占和T優(yōu)272根際土壤中Cd的交換態(tài)含量呈現(xiàn)下降趨勢,可分別下降12.6%～39.8%和20.6%～70.6%;QFJ施用量在0.5～2.0 g·kg-1之間對As的交換態(tài)含量有降低作用,分別降低12.2%～55.1%和7.0%～39.5%,但施用量增加后使得交換態(tài)As含量急劇增大。隨著QFJ施用量的增加,土壤中Cd的毒性浸出量逐漸下降,As的毒性浸出量先下降后上升。土壤pH值、CEC與土壤中Cd的交換態(tài)含量、毒性浸出量及酸提取態(tài)含量具有正的線性關(guān)系;土壤pH值與土壤中As的交換態(tài)含量、毒性浸出量具有負(fù)的線性關(guān)系。(3)盆栽實(shí)驗(yàn)中,施用QFJ改變了 Cd和As的賦存形態(tài),降低了 Cd酸提取態(tài)含量,使難溶的有機(jī)結(jié)合態(tài)Cd分別增加6.8%～49.5%和2.5%～56.5%;同時(shí),降低了As交換態(tài)含量,使難溶的鈣結(jié)合態(tài)As含量分別增加34.1%～93.4%和2.8%～53.3%;但QFJ施用量超過4.0 g·kg-1時(shí),土壤中交換態(tài)As含量增大。(4)盆栽實(shí)驗(yàn)中,QFJ施用使得水稻各部位Cd含量均低于對照組CK,糙米中Cd含量可從0.49 mg·kg-1下降到0.11 mg·kg-1;水稻植株各部位Cd的含量大小依次是根莖葉糙米谷殼。QFJ施用量控制在0.5～2.0g·kg-1水平,顯著降低水稻地上各部位As含量,且在2.0 g·g-1施用量,2種水稻糙米中As含量從0.27 mg·kg-1、0.28mg·kg-1下降到最低值0.11mg·kg-1、0.16mg·kg-1,但隨著施用量的增加,水稻各部位中As含量呈現(xiàn)上升趨勢;水稻植株各部位As含量大小依次是根莖葉谷殼糙米。(5)盆栽實(shí)驗(yàn)顯示,水稻根系對Cd和As的富集系數(shù)BAF分別為0.65～1.26和0.024-0.061,根系富集Cd的能力較As強(qiáng);水稻各部位對Cd的轉(zhuǎn)運(yùn)系數(shù)TF依次是TFCd-hbTFCd-shTFCd-rs,對 As 的是 TFAs-rsTFAs-hbTFAs-sh,水稻谷殼對 Cd 的轉(zhuǎn)運(yùn)能力最強(qiáng),而根對As的轉(zhuǎn)運(yùn)能力最強(qiáng);QFJ的施用降低了水稻植株對Cd和As轉(zhuǎn)運(yùn)量的系數(shù),有效降低了水稻植株地上部位Cd和As的累積總量。(6)田間實(shí)驗(yàn)顯示,隨著QFJ施用量的增加,2礦區(qū)水稻各生育期根際土壤pH值、CEC和OM含量有增大趨勢;QFJ的施用在各生育期均可顯著降低2礦區(qū)土壤中交換態(tài)Cd含量,且在水稻分蘗期時(shí),降低土壤交換態(tài)Cd含量的幅度最大;而針對土壤交換態(tài)As含量2個(gè)礦區(qū)呈現(xiàn)相反的結(jié)果,A礦區(qū)有增大風(fēng)險(xiǎn)而B礦區(qū)呈現(xiàn)降低風(fēng)險(xiǎn)的趨勢。QFJ的施用也可顯著降低水稻各生育期2礦區(qū)土壤中Cd的毒性浸出量,對B礦區(qū)土壤As的毒性浸出量也有降低的作用,但對土壤A礦區(qū)中As的毒性浸出量,在4.0 g·kg-1施用量時(shí)則有提高的風(fēng)險(xiǎn)。(7)田間實(shí)驗(yàn)顯示,灌漿期是水稻植株大量累積Cd和As的時(shí)期。QFJ的施用可有效降低A礦區(qū)(土壤Cd總量3.58 mg·kg-1,As總量124.79 mg kg-1)各生育期水稻各部位中Cd含量,也可降低成熟期水稻各部位中As含量。QFJ施用量在4.0g·kg-1水平時(shí),使成熟期糙米Cd含量從0.46mg·kg-1下降到0.18mg·kg-1,無機(jī)As含量從0.22 mg·kg-1降低到0.18 mg·kg-1,糙米中Cd和無機(jī)As含量同時(shí)低于0.2 mg·kg-1,達(dá)到水稻安全生產(chǎn)要求。
[Abstract]:With the rapid development of industry and agriculture in China, the problems of heavy metal pollution such as Cd and As are becoming more and more serious in our country. Hunan province is the home of non-ferrous metals and Yumizhixiang, scale mining and smelting has brought serious damage to the ecological environment and agricultural production, which seriously restricts the safety of rice production and rice area of Hunan province food safety. How to control the Cd and As compound polluted farmland and how to control the transfer of Cd and As into rice is an urgent environmental problem. The repair of Cd and As in paddy soil around the composite pollution in Chenzhou mining area, Shizhuyuan (A mine) and Xiangxi County of Baojing Fuxing Village area (B area) of different soil Cd and As pollution in paddy field as the research object, through improved agent selection research, water adsorption experiment, pot experiment and field experiment of rice so, developing a group with a modifier QFJ, application of QFJ and As decreased soil Cd bioavailability and rice Cd, As content mechanism, put forward a set of effective technical control of paddy field Cd and As bioavailability and transfer. The results are as follows: (1) developed with hydroxyapatite, zeolite and modified straw charcoal 3 kinds of materials as the main ingredient, modifier QFJ according to a certain weight proportion group, determine the mechanism: 3 material has larger specific surface area, surface adsorption can occur and pore adsorption with Cd2+ and As5+ solution in QFJ, -OH, -COOH, containing -Si-O-Si and C032- groups and Cd2+ in solution, As5+ ion exchange adsorption, covalent binding, formation of carboxylic acid salts, silicate and carbonate species, which will be free in the soil solution Cd2+, As3+ and As5+ in situ passivation. (2) the experiment of rice pot experiments showed that the content of pH, CEC and OM in rhizosphere soil showed an upward trend with the use of the combination of QFJ and As to improve the soil soil of Cd and As. The application of QFJ makes the rice Huang Huazhan and T 272 in the rhizosphere soil exchangeable Cd content showed a downward trend, can be reduced by 12.6% ~ 39.8% and 20.6% ~ 70.6% respectively; QFJ fertilizer with exchangeable content of As between 0.5 ~ 2 g / kg-1 decreased, decreased by 12.2% ~ 55.1% and 7% ~ 39.5% respectively., but increased the concentration of exchangeable As increased sharply. With the increase of the amount of QFJ, the toxic leaching of Cd in the soil decreased gradually, and the toxic leaching amount of As decreased first and then increased. There was a positive linear relationship between soil pH and CEC and the content of exchangeable Cd in soil, the amount of toxic leaching and the content of acid extract. The pH value of soil had negative linear relationship with the exchange state content of As and the amount of toxic leaching. (3) pot experiment, the application of QFJ has changed the chemical speciation of Cd and As, decreased Cd acid extractable content, the organic combination of insoluble Cd increased 6.8% ~ 49.5% and 2.5% ~ 56.5%; at the same time, reduce the content of exchangeable As, the insoluble calcium bound As was increased by 34.1% ~ 93.4% and 2.8% ~ 53.3% respectively; but the QFJ dosage is more than 4 g - kg-1, increase the content of the exchangeable As in soil. (4) pot experiment, QFJ application makes the Cd content in different parts of rice were lower than the control group CK, Cd content in brown rice decreased from 0.49 mg to 0.11 mg - kg-1 - kg-1; the size of each part of Cd content in rice plant in rhizome and leaf of rice husk. Control QFJ application amount in the range of 0.5 ~ 2.0g and kg-1 levels decreased significantly on As content in different parts of rice, and in 2 G - g-1 fertilizer, 2 kinds of As content in brown rice from 0.27 Mg - kg-1, 0.28mg - kg-1 dropped to the lowest value of 0.11mg - kg-1, 0.16mg - kg-1, but with the increasing of the amount the As content in different parts of rice in rice plants showed an upward trend; As contents in different parts of the size of the order is the rhizome and leaf of brown rice husk. (5) pot experiment showed that the enrichment coefficient of BAF rice root of Cd and As were 0.65 ~ 1.26 and 0.024-0.061, the ability of root enrichment of Cd is stronger than As; transfer coefficient TF on Cd in different parts of rice followed by TFCd-hbTFCd-shTFCd-rs, As TFAs-rsTFAs-hbTFAs-sh, transport capacity of the strongest rice shell on the Cd Valley, and the root of the As transport capacity of the strongest; QFJ application decreased the coefficient of Cd and As translocation amount of rice plants, effectively reducing the rice plants on site Cd and As cumulative total. (6) field experiments show that with the increase of QFJ dosage, 2 in different growth stages of rice rhizosphere soil pH, CEC and OM content increased; the administration of QFJ decreased significantly in each growth period can be exchangeable Cd content of 2 Soil in mining area, and at the tillering stage, decrease soil exchange state Cd content is the biggest; while the contents of soil exchangeable As 2 mining areas showed the opposite results, A and B have an increased risk of mining area showed a decreasing trend in risk. The application of QFJ can also significantly reduce the toxic leaching amount of Cd in the 2 mining area soil at different growth stages, and decrease the toxic leaching amount of As in B mining area. However, the toxic leaching amount of As in soil A mining area is increased at 4 g / kg-1 dose. (7) field experiments showed that the grain filling period was a period of accumulation of Cd and As in rice plants. The application of QFJ can effectively reduce the A mining area (total Cd content of soil 3.58 mg kg-1, As total 124.79 mg kg-1). The Cd content in different parts of rice at different growth stages can also reduce the As content in different parts of mature rice. When QFJ dosage was 4.0g / kg-1, the content of Cd in brown rice decreased from 0.46mg to kg-1, 0.18mg to kg-1, and the content of inorganic As decreased from 0.22 mg to 0.18, and the content of inorganic and inorganic compounds in brown rice was lower than 0.2.
【學(xué)位授予單位】：中南林業(yè)科技大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：S511;X53
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本文編號：1344023