组配改良剂对稻田系统中重金属及砷的调节与控制

发布时间：2018-01-11 11:18

本文关键词：组配改良剂对稻田系统中重金属及砷的调节与控制　出处：《中南林业科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：本论文研究了水稻不同生育期根际和非根际土壤中砷形态的迁移和转化规律：研究了不同改性的高岭土(煅烧、煅烧+HC1、煅烧+NaOH.煅烧+A12(SO4)3)和碳酸钙及钙镁磷肥对土壤中重金属及砷的固化效果。将上述固化材料进行多比例的两相或三相组配,筛选出效果较好的1个组配(碳酸钙+偏高岭土+钙镁磷肥4：2：1,以下简称为LMF),施用与水稻盆栽试验土壤中,研究了在不同施用量下(0、0.5、1、2、4、8、16g·kg-1)组配改良剂LMF对模拟稻田系统中重金属和砷的固化效果,以及水稻各部位对重金属和砷的吸收与累积。主要研究结果如下：(1)随着水稻生育期的延长,根际及非根际土壤pH值和砷TCLP提取态含量均逐渐上升,且非根际土壤pH值和砷TCLP提取态含量均高于同时期根际土壤。水稻各生育期根际和非根际土壤中交换态砷(Ex-As)含量均低于水稻种植前,并随着水稻生育期的延长逐渐上升。与水稻种植前相比,铝型砷(Al-As)、铁型砷(Fe-As)和钙型砷(Ca-As)含量在水稻种植后逐渐上升,但并不显著。残渣态砷(O-As)和总砷(T-As)含量在水稻种植后逐渐下降,在根际土壤中下降了37.30%和14.69%,非根际土壤中下降了31.38%、8.67%。在水稻不同生育期,土壤各形态砷含量均表现为：残渣态铁型砷铝型砷钙型砷交换态砷。残渣态砷含量占总砷的46.5%-68.3%,交换态砷所占比例不到0.5%。(2)在高岭土改性筛选试验中,添加4g·kg-1的煅烧改性高岭土,土壤中交换态砷、铅、镉(Ex-As, Ex-Pb, Ex-Cd)含量分别降低了32.14%、13.03%和2.78%；土壤中砷、铅、镉各TCLP提取态(TCLP-As, TCLP-Pb, TCLP-Cd)含量分别下降了29.91%、10.09%和1.27%。4：2：1的碳酸钙+煅烧改性高岭土+钙镁磷肥(以下简称LMF)是对土壤重金属和砷综合固化效果最好的一组,与空白相比,添加4g·kg-1的LMF,土壤pH值上升了1.75个单位,土壤中交换态砷、铅、镉(Ex-As, Ex-Pb, Ex-Cd)含量分别降低了92.86%、93.33%和19.10%；土壤中砷、铅的TCLP提取态(TCLP-As, TCLP-Pb)含量分别下降了43.60%、23.17%,对镉的TCLP提取态含量无显著影响。(3)在水稻盆栽试验中,随着组配改良剂LMF施用量的增加,土壤pH值、交换性盐基总量(TEB)和阳离子交换量(CEC)均呈上升趋势,盐基饱和度(BS)和有机质(OM)含量无明显变化规律。施用LMF对土壤重金属Pb、Cd的赋存形态产生显著影响,能显著降低Pb, Cd酸可提取态含量和Pb有机结合态含量,略微提高Pb铁锰氧化物结合态和残渣态含量,对Cd铁锰氧化物结合态、残渣态含量和总量无显著影响。随着LMF施用量的增加,TCLP提取态Pb的含量逐渐降低,TCLP提取态Cd的含量无显著变化。施用LMF对SH(水稻种植前)和CS(水稻收获后)土壤中As的各形态含量影响均不相同,随着组配改良剂施用量的增加,两种土壤中交换态As均呈现出先下降后上升的趋势。两种土壤交换态As含量的变化均是在组配改良剂施用量为2mg·kg-1时含量最低。(4)在水稻盆栽试验中,施用组配改良剂LMF能影响水稻各个部位中Pb、Cd和As含量。随着LMF施用量的增加,糙米中Pb、Cd含量逐渐降低,与对照相比,Pb、Cd分别降低了8.44%～99.57%、27.49%～74.05%。当LMF施用量为16 g·kg-1时,糙米中Pb、Cd含量分别为0.002 mg·kg-1、0.185 mg·kg-1,低于国家食品中污染物限量标准(GB 2762-2012)中大米Pb和Cd的限量(0.20mg·kg-1)。糙米中Pb、Cd、As的含量与土壤中各活性较高的提取态(酸可提取态、交换态、TCLP提取态)含量均呈现显著或极显著的相关关系。
[Abstract]:This paper studies the migration and transformation regularity of arsenic speciation in different growth stages of rice rhizosphere and non rhizosphere soil in different modified kaolin were studied (calcination, calcination +HC1, +NaOH. calcined calcined +A12 (SO4) 3) and calcium carbonate and calcium magnesium phosphate on heavy metals and arsenic in soil. The effect of solid phase with the group or three-phase multi curing material proportion, selected 1 groups with better effect (calcium carbonate + metakaolin + calcium magnesium phosphate 4:2:1, hereinafter referred to as LMF), and the application of rice pot experiment in soil was studied under different application amounts (0,0.5,1,2,4,8,16g - kg-1) group with curing effect modifier LMF on heavy metal and arsenic paddy simulation system, and in different parts of heavy metal and arsenic uptake and accumulation. The main results are as follows: (1) with the increase of rice growth period, soil pH in the rhizosphere and non rhizosphere TCLP value and extractable content The amount was increased gradually, and the non rhizosphere soil pH content were higher than the same period of extraction and TCLP in rhizosphere soil. The growth period of rice rhizosphere and non rhizosphere soil exchangeable arsenic (Ex-As) content were lower before planting rice, and increased with the growth period of rice increased gradually. Compared with the rice before planting, aluminium arsenic, iron arsenic (Al-As) (Fe-As) and calcium arsenic (Ca-As) content increased gradually in rice cultivation, but not significant. The residue of arsenic (O-As) and total arsenic (T-As) content decreased in rice cultivation, in the rhizosphere soil decreased by 37.30% and 14.69% and in non rhizosphere soil decreased by 31.38%, 8.67%. in different growth stages of rice, the arsenic content in the soil are as follows: the residual iron arsenic arsenic aluminum calcium arsenic arsenic. The arsenic content of exchangeable residual total arsenic 46.5%-68.3%, exchangeable arsenic accounted for less than 0.5%. (2) in Gaoling modified screening tests, Add 4G kg-1 calcined modified kaolin, arsenic, lead and cadmium in the soil exchange, (Ex-As, Ex-Pb, Ex-Cd) content decreased by 32.14%, 13.03% and 2.78%; the soil arsenic, lead, cadmium, TCLP extractable (TCLP-As, TCLP-Pb, TCLP-Cd) content decreased by 29.91%, calcium carbonate calcination 10.09% and 1.27%.4:2:1 modified kaolin + calcium magnesium phosphate (hereinafter referred to as LMF) is on the soil heavy metals and comprehensive curing effect of the best group, compared with blank, add 4G and kg-1 LMF, soil pH value increased by 1.75 units, arsenic, exchange of lead in soil, cadmium (Ex-As, Ex-Pb, Ex-Cd) content decreased by 92.86%, 93.33% and 19.10%; the soil arsenic, lead TCLP extractable (TCLP-As, TCLP-Pb) content decreased by 43.60%, 23.17%, on CD TCLP extractable content had no significant effect. (3) in rice in the pot experiment, with the increase of group with modifier LMF fertilizer, soil pH The value of total exchangeable base (TEB) and cation exchange capacity (CEC) showed an upward trend, base saturation (BS) and organic matter (OM) content had no significant change. LMF application on soil Pb, significantly affect the chemical speciation of Cd, can significantly reduce the Pb, Cd acid extractable content Pb and organic boundforms, slightly increased Pb iron manganese oxide bound and residual content of Cd Fe Mn oxides, had no significant effect of residue content and total. With the increase of LMF dosage, extraction content of Pb decreased gradually and TCLP, TCLP content Cd showed no significant changes. The application of LMF to SH (before planting rice) and CS (rice harvest) affect the content of soil in the form of As are not the same, with the increasing dosage group with modified agent, two kinds of soil exchangeable As showed an upward trend after the first drop. Two kinds of soil exchangeable As content change All is in the group with amendments is 2mg - kg-1 (4). The lowest content in rice in the pot experiment, the application of combined amendments LMF can affect all parts of rice in Pb, Cd and As content. With the increase of LMF dosage, rice Pb, Cd content decreased gradually, and the control compared to Pb, Cd were decreased by 8.44% ~ 99.57%, 27.49% ~ 74.05%. when LMF application amount was 16 g kg-1, Pb Cd content in brown rice, respectively, 0.002 mg - kg-1,0.185 Mg - kg-1, lower than the national food standard of pollutants (GB 2762-2012) in rice Pb and Cd Limited (0.20mg - kg-1). Pb Cd, brown rice, the high activity extractable content and soil in As (acid extractable, exchangeable, TCLP extractable) content showed significant correlations.

【学位授予单位】：中南林业科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X56;S511

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