BDE209-Pb复合污染与土壤微生物和蚯蚓相互作用及其机制

发布时间：2018-05-12 22:11

本文选题：BDE209-Pb + 土壤微生物　；参考：《华东理工大学》2017年硕士论文

【摘要】：随着电子技术迅猛发展,电子垃圾已成为全球性的环境问题。电子垃圾中多溴联苯醚和重金属等有害物质进入土壤环境后,会严重危害生态系统和人体健康。本论文选取电子垃圾中典型的多溴联苯醚(十溴联苯醚,BDE209)和重金属(铅,Pb)作为目标污染物,赤子爱胜蚓(Eisenia fetida)作为模式生物,研究土壤微生物和蚯蚓对BDE209-Pb复合污染土壤的生物修复作用,以及BDE209-Pb对土壤微生物和蚯蚓的毒性效应。主要结论如下:(1)与对照组相比,蚯蚓能显著促进土壤中BDE209和Pb的去除(p0.05),28 d后CS1和CS5实验组土壤中BDE209的去除率分别为14.12%和14.93%,CS2和CS3实验组土壤中Pb的去除率分别为23.96%和25.71%。土壤污染初期(2 d),Pb主要以CAR-Pb和FeMnOX-Pb两种形态存在,Pb风险水平较高(LV4,LV5)。在微生物作用下Pb逐渐转化为FeMnOX-Pb和OMB-Pb两种更稳定形态,生物有效性降低,28 d后Pb风险水平降至中等或低水平(LV2,LV3)。然而,蚯蚓的存在增加了土壤中EXCH-Pb和CAR-Pb的含量。(2)土壤对Pb有较强的吸附作用,且吸附特征符合Langmuir和Freundlich等温吸附方程(R2分别为0.994和0.978)。土壤pH、氧化还原电位Eh和腐殖质含量等会对Pb的形态产生影响。pH越高、Eh值越低、腐殖质特别是胡敏酸含量越高,Pb有效性越低。此外,微生物对Pb也有一定吸附作用,这可能与微生物细胞中O-H、C-H、C=O、O-C=O、N-H、C-O、C-O-C 等基团有关。(3)土壤中BDE209和Pb会抑制微生物的生长,导致微生物生物量和土壤呼吸强度下降,且表现出明显的剂量效应关系(p0.05或0.01)。与空白组相比,S1、S2、S3、S4和S5实验组土壤呼吸强度分别减少了 5.41%、14.19%、32.43%、39.19%和39.86%(28 d)。而蚯蚓的存在会提高微生物生物量和土壤呼吸强度,2d后CS1实验组土壤呼吸强度达到28.3mgCO2kg-1 d-1,是S1实验组的两倍(p0.01)。此外,第14d两中体系土壤中EXCH-Pb浓度与土壤呼吸强度的剂量-效应关系显著(R2分别为0.949和0.988),两者高度显著的相关性关系可以用来评价土壤生态风险。(4)BDE209和Pb会对蚯蚓造成急性毒性损伤,符合剂量/时间效应关系(暴露72 h时R2分别为0.933和0.940),其中Pb对蚯蚓的毒害作用更大。暴露28 d后,低浓度胁迫会显著诱导蚯蚓SOD活性(p0.01),而高浓度胁迫会损害蚯蚓细胞并抑制SOD和CAT活性(p0.01或0.05)。此外,BDE209和Pb也会对蚯蚓溶酶体膜造成损害,且污染物浓度越高,损害程度越大(p0.01)。
[Abstract]:With the rapid development of electronic technology, electronic waste has become a global environmental problem. The harmful substances such as PBDEs and heavy metals in e-waste will seriously endanger ecosystem and human health when they enter the soil environment. In this paper, the typical polybrominated diphenyl ethers (BDE209) and heavy metals (Pb Pb) in electronic waste were selected as target pollutants and Eisenia fetida as model organism. The effects of soil microorganisms and earthworms on bioremediation of BDE209-Pb contaminated soil and toxicity of BDE209-Pb on soil microbes and earthworms were studied. The main conclusions were as follows: compared with the control group, earthworm could significantly promote the removal of BDE209 and Pb from the soil. After 28 days, the removal rates of BDE209 in the experimental groups of CS1 and CS5 were 14.12% and 14.93% respectively. The removal rates of BDE209 in the experimental groups were 23.96% and 25.71%, respectively. In the initial stage of soil pollution, the main forms of CAR-Pb and FeMnOX-Pb are CAR-Pb and FeMnOX-Pb, and the risk level of Pb is higher than that of LV4 / LV5. Under the action of microorganism, Pb was gradually transformed into two more stable forms, FeMnOX-Pb and OMB-Pb, and the Pb risk level decreased to the middle or low level of LV2 / LV3 after 28 days of reduction of bioavailability. However, the presence of earthworms increased the contents of EXCH-Pb and CAR-Pb in soil. Soil pH, redox potential (Eh) and humus content will affect the morphology of Pb. The higher pH is, the lower the value of Eh is, and the higher the content of humus, especially Hu Min, the lower the availability of Pb. In addition, microbes can also adsorb Pb to some extent, which may be related to the groups such as O-HG C-HHCU, OO-CU, OOO-C and so on.) BDE209 and Pb in soil can inhibit the growth of microbes and lead to the decrease of microbial biomass and soil respiration intensity. And showed a significant dose-effect relationship (p0.05 or 0.01). Compared with the control group, the soil respiration intensity in the S1-S2S3-S4 and S5 groups decreased by 5.41% and 14.19%, respectively, and that in the control group was 39.19% and 39.86%, respectively. However, the presence of earthworms increased the microbial biomass and soil respiration intensity 2 days later, the soil respiration intensity of CS1 experimental group reached 28.3mgCO2kg-1 d-1, which was twice than that of S1 experimental group (p0.01). In addition, On the 14th day, the dose-effect relationship between soil EXCH-Pb concentration and soil respiration was 0.949 and 0.988, respectively. The highly significant correlation between them could be used to evaluate the acute toxicity of soil ecological risk. The corresponding dose-time effect relationship (R2 was 0.933 and 0.940g respectively at 72 h exposure), in which Pb was more toxic to earthworms. After 28 days of exposure, the SOD activity of earthworms was significantly induced by low concentration stress, while the high concentration stress could damage earthworm cells and inhibit the activities of SOD and CAT (p0.01 or 0.05). In addition, BDE209 and Pb also caused damage to the lysosomal membrane of earthworm, and the higher the pollutant concentration, the greater the damage degree was.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53;X17

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