施用不同比例熟化污泥改良土壤中重金属镉的行为特征及生物有效性研究

发布时间：2018-05-08 19:09

本文选题：熟化污泥 + 小麦　；参考：《兰州大学》2015年硕士论文

【摘要】：由于我国工业化的快速推进,污泥的产量也在与日俱增,如何合理地处置污泥也是当前国内外的研究讨论的焦点。污泥中含有丰富的有机质与各类植物生长所需之养分,因此,土地利用是最为看好的城市污泥处置与资源化方式。本研究,针对干早区黄土—小麦系统,设计科学、合理的盆栽试验,模拟干旱区受不同程度Cd污染条件下施加不同比例(1.5%、3%)熟化污泥于黄土,探究其对小麦生长与吸收富集Cd之影响,为未来污泥土地施用提供参考。本试验得出的主要结果如下：(1)随着熟化污泥添加量的增加,土样的pH值逐渐的降低,电导率、有机质以及镉的含量逐渐的升高,对镉的吸附固定作用越强。有机质成分是对试供土样固定镉的能力影响最大的因素。(2)Cd的胁迫会促进土壤中Cd的有效态分配系数,从而促进植物的吸收,对植物存在威胁。但熟化污泥的添加,土壤中Cd的有效态分配系数降低,对土壤中Cd可起到一定的固定作用,主要原因是熟化污泥中有机质含量丰富,易于形成有机态Cd,但仍存在一定危险,在一定条件下,有机态会被微生物分解而缓慢释放到土壤中。(3)施用熟化污泥可以有效促进小麦地上部分的生长,并且3%污泥施加比例较1.5%更有利于促进小麦地上部分的生长,各部分促进程度：茎叶籽粒。与未施加污泥组相较,在S6水平并且施加3%污泥条件下,小麦株高最大增幅达到117%,在黄土中添加3%污泥并在S8(12mg/kg)水平下,小麦茎叶干重为9.757±0.353g,增长率最大约为336.75%,小麦籽粒干重为13.433±0.13g,增长率最大为2329.11%。(4)在低浓度Cd胁迫水平下(0-10mg/kg),施用熟化污泥可抑制小麦各部分对Cd的吸收作用。抑制程度：根籽茎叶。但当Cd浓度超过10mg/kg,熟化污泥的施用将对小麦带来重金属污染危害。(5)小麦各部位对Cd的富集能力为：根系茎叶籽粒,表明Cd更易从土壤系统进入植物系统并富集于小麦根部,而在籽粒中的富集则较少。污泥的施用在一定程度上抑制Cd在小麦各部分的富集,但影响并不显著。同时,污泥的施用较大程度的促进了Cd从茎叶向籽粒的迁移,而对Cd从根向茎叶的迁移影响不显著。
[Abstract]:Due to the rapid development of industrialization in China, sludge production is increasing day by day, and how to dispose sludge rationally is the focus of current domestic and international research and discussion. Sludge is rich in organic matter and nutrients needed for plant growth. Therefore, land use is the most promising way to dispose and recycle municipal sludge. In this study, a scientific and reasonable pot experiment was designed for the Loess wheat system in dry and early areas, and the sludge maturation in loess was simulated under different CD pollution conditions. The effects of CD on wheat growth and CD uptake were investigated to provide a reference for the application of sludge land in the future. The main results of this experiment are as follows: (1) with the increase of sludge addition, the pH value of soil samples decreases gradually, the conductivity, organic matter and cadmium content increase gradually, and the adsorption and fixation of cadmium is stronger. Organic matter is the most important factor affecting the ability of soil samples to immobilize cadmium. The stress of CD can promote the effective distribution coefficient of CD in soil, thus promote the uptake of CD by plants and threaten the plants. However, with the addition of matured sludge, the available distribution coefficient of CD in soil decreased, and CD in soil could be fixed to a certain extent. The main reason was that the organic matter in the sludge was rich in organic matter and it was easy to form organic CD, but there was still some danger. Under certain conditions, organic state will be decomposed by microorganism and released into soil slowly.) the application of matured sludge can effectively promote the growth of wheat aboveground part, and the application of 3% sludge is more favorable than 1.5% sludge to promote the growth of wheat aboveground part. Promote degree of each part: stem leaf grain. Compared with the untreated sludge group, under the condition of S6 and 3% sludge, the maximum increase of wheat plant height was 117g / kg, the addition of 3% sludge to loess and the addition of 12 mg / kg of sludge to the loess, The dry weight of stem and leaf of wheat was 9.757 卤0.353 g, the maximum growth rate was 336.75 g, the dry weight of wheat grain was 13.433 卤0.13 g, and the maximum growth rate was 2329.11.1 mg 路kg ~ (4) under low concentration of CD stress, the application of matured sludge could inhibit the absorption of CD by different parts of wheat. Inhibition degree: root seed stem and leaf. But when CD concentration is more than 10 mg / kg, the application of matured sludge will bring heavy metal pollution harm to wheat. The accumulation ability of CD in different parts of wheat is as follows: root, stem, leaf and grain, indicating that CD is more easily entered into plant system from soil system and enriched in wheat root. However, there was less enrichment in grain. The application of sludge inhibited the accumulation of CD in all parts of wheat to some extent, but the effect was not significant. At the same time, the application of sludge promoted the migration of CD from stem and leaf to grain to a large extent, but had no significant effect on the migration of CD from root to stem and leaf.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X703

【共引文献】