| 题名 | 典型溴代阻燃剂对赤子爱胜蚓的分子生态毒性效应 |
| 作者 | 徐湘博 |
| 学位类别 | 硕士 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 史雅娟 |
| 关键词 | 溴代阻燃剂 赤子爱胜蚓 生长抑制率 酶活 基因表达量 Brominated flame retardants Eisenia fetida Growth inhibition Enzyme activity Gene expression |
| 其他题名 | The Effects of Brominated Flame Retardants on MolecμLar Ecological Toxic Effects of Earthworms (Eisenia fetida) |
| 学位专业 | 环境工程 |
| 中文摘要 | 多溴联苯醚（Polybrominated diphenyl ethers，PBDEs）因其优异的阻燃性能而成为生产量最高的溴代阻燃剂（Brominated flame retardants，BFRs）。近年来，部分 PBDEs由于具有持久性有机污染物的特性受到限制生产和使用，四溴双酚A（Tetrabromobisphenol A，TBBPA）和六溴环十二烷（Hexabromocyclododecane，HBCD）作为替代物成为 BFRs的主流产品。目前，溴代阻燃剂对土壤生态系统的毒性效应的研究尚不完善，为此本研究选择 4种典型 BFRs为研究对象，包括：2,2’,4,4’-四溴联苯醚（ 2,2’,4,4’-tetrabromodiphenyl ether，BDE-47）毒性较高的PBDEs同系物之一、十溴联苯醚（Decabromodiphenyl ether，BDE-209）唯一被允许生产的 PBDEs同系物单体、TBBPA和 HBCD，开展 4种 BFRs对赤子爱胜蚓的毒性效应研究，不仅为这 4种 BFRs的毒性效应提供基础数据，还可以为工 业生产提供有价值的参考资料。 本论文采用人工土壤法，从个体、酶活和基因表达三个层面研究了 BDE-47暴露 14 d和 42 d对赤子爱胜蚓的毒性效应。同时还从个体和基因表达两个角度比较了 BDE-47、BDE-209、TBBPA和 HBCD暴露 14 d对赤子爱胜蚓的毒性效应。研究结果如下： 1、BDE-47对赤子爱胜蚓的毒性效应研究 1）个体层面 在 BDE-47 14 d的暴露毒性试验中，随着 BDE-47暴露浓度的增加，蚯蚓的生长抑制率显著升高，并且具有剂量效应关系（p <0.01）。 2）酶活层面 在 BDE-47暴露 14 d和 28 d时，CAT活性被诱导上升并且具有显著性差异（p <0.01），42 d时，处理组与对照组相比，CAT活性无显著性差异；GST活性变化不显著（p >0.05）。 3）基因层面 BDE-47暴露 14 d后，随着 BDE-47暴露浓度的增加，SOD基因表达量显著上调，并且在 400 mg/kg dw染毒组达到最大值（3.84倍，p<0.01）；Hsp70的基因表达量随着 BDE-47暴露浓度的增加被诱导下调，并且变化趋势相似，与对照组相比，在 100、200和 400 mg/kg dw染毒组都具有显著性差异（p <0.05）。CAT基因表达水平，在 14 d时呈现抑制效应（p <0.01），在 28 d基因表达水平上调（200mg/kg dw，p <0.05），42 d时基因表达水平无显著性变化。GST基因表达水平，在 14、28、42 d时整体呈现诱导效应，并且差异显著（p <0.05）。随着暴露时间的增加，低毒处理组的 CAT和 GST基因表达水平逐渐下调至低于对照组的水平，高毒处理组的 CAT和 GST基因表达量仍高于对照组水平。 2、BDE-209对赤子爱胜蚓的毒性效应研究 在毒性暴露 14 d后，随着浓度的增加，BDE-209各处理组与对照组相比，生长抑制率和 SOD、CAT、GST、Hsp70基因表达量的变化均无显著性差异。 3、TBBPA对赤子爱胜蚓的毒性效应研究 随着 TBBPA暴露浓度的增加，TBBPA各处理组与对照组相比，生长抑制率明显高于对照组。SOD基因的表达呈现诱导效应，并在 50 mg/kg dw处理组达到最大值（1.77倍，p<0.01）；GST基因的表达也呈现诱导效应，在 400 mg/kg dw处理组（8.73倍，p<0.01）诱导效应明显；Hsp70基因的表达呈现诱导效应，在50、100和 200 mg/kg dw处理组诱导效应明显（2.19倍，p<0.01；2.17倍，p<0.01；2.16倍，p<0.01）；CAT基因表达量的变化没有显著差异。 4、HBCD对赤子爱胜蚓的毒性效应研究 在 14 d暴露期内，随着浓度的增加，HBCD各处生长抑制率没有显著差异，SOD基因的表达在 400 mg/kg dw处理组（2.06倍，p<0.01）呈现出诱导效应；Hsp70基因的表达只有在 400 mg/kg dw处理组（2.16倍，p<0.01）呈现出诱导效应，CAT和 GST基因表达量的变化没有显著差异。 5、BDE-47、BDE-209、TBBPA和 HBCD对赤子爱胜蚓毒性效应比较 1）生长抑制作用：相同暴露浓度下 BDE-47对赤子爱胜蚓的毒性效应最明显，次之是 TBBPA，BDE-209和 HBCD无显著性影响。 2）SOD、CAT和 GST基因表达量的变化表明：BDE-47对赤子爱胜蚓的毒性效应最大，次之是 TBBPA，HBCD和 BDE-209毒性效应最小。而 4种 BFRs对 Hsp70基因表达量影响的模式不同，BDE-47对其影响呈现抑制效应，TBBPA和 HBCD对其影响呈现诱导效应。 综合比较 4种 BFRs对赤子爱胜蚓生长抑制率和基因表达量的影响，4种物质毒性效应大小的顺序为： BDE-47>TBBPA>BDE-209, HBCD。由于 BDE-209可降解为毒性更高的低溴代联苯醚以及结合赤子爱胜蚓急性毒性试验结果，可推知：在这 4种溴代阻燃剂中，HBCD的生产和使用对土壤生态系统的不利影响是最小的。 |
| 英文摘要 | Polybrominated diphenyl ethers (PBDEs), the top one brominated flame retardants (BFRs), have been extensively produced and used until 2009 when some PBDEs were listed in the Stockholm Convention, and their use has been restricted and forbidden, tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCD) became main alternatives of PBDEs. At present, the toxic effects of BFRs on earthworms were scarcely reported. In this study, 2,2’,4,4’ - tetrabromodiphenyl ether (BDE-47), one of leading monomer of PBDEs; decabromodiphenyl ether (BDE-209), the unique monomer of PBDEs in production; TBBPA and HBCD, the alternatives of PBDEs,were selected as the representatives of BFRs. The toxic effects of BDE-47, BDE-209, TBBPA and HBCD on earthworms Eisenia fetida were investigated. The resμLts will provide not only scientific evidences for ecological risk assessment, but also sµggestions to the industrial production of BFRs. The growth inhibition, enzyme activity and gene expression were detected to explore the toxic effects of BDE-47 on earthworms Eisenia fetida after exposure for 14 and 42 days. Furthermore, the biomarks of growth and gene expression were used to compare the toxic effects to earthworms Eisenia fetida after exposure to BDE-47,BDE-209, TBBPA and HBCD for 14 days. The resμLts are as follows: 1. The toxic effects of BDE-47 on earthworms Eisenia fetida 1) The individual level effects With the increase of the exposure concentrations of BDE-47, the growth inhibition rates of earthworms of all BDE-47 dose groups were significantly higher than those of controls in 14d toxicity test. Significant dose-response relationship(p<0.01) was shown between BDE-47 concentrations and growth inhibition rates. 2) The enzyme activity. The activity of CAT was significantly inducted after exposure to BDE-47 for 14 and 28 d（p <0.01）, but no significant changes was shown for 42 d. The activity of GST was changed insignificantly（p >0.05） 3) The level of gene expression. The SOD gene expression was up-regμLated at all BDE-47 exposure doses (400mg/kg dw, 3.84-fold, p<0.01). The significant down-regμLation of Hsp70 was present at the concentrations of 100, 200, 400 mg/kg dw (p<0.05) in 14 d toxicity test. In general, BDE-47 mainly significantly induced the gene expression levels of GST in 42 d exposure time and significantly inhibited the gene expression levels of CAT at 14d. With the increase of exposure time, the gene expression levels of CAT and GST recovered to level of the control group at low concentration group and remained the state of induction at high concentration group. 2. The toxic effects of BDE-209 to earthworms Eisenia fetida The growth inhibition rates and gene expression levels of all BDE-209 groups were not significantly different when compared with controls. 3. The toxic effects of TBBPA to earthworms Eisenia fetida With increase of the exposure concentrations of TBBPA, the growth inhibition rates of TBBPA dose groups were significantly higher than those of controls. SOD gene expression was up-regμLated at the concentration of 50 mg/kg dw (1.77-fold,p<0.01). Significant up-regμLation of GST gene expression presented at the concentrations of 400 mg/kg dw (8.73-fold, p<0.01). Earthworms exposure to TBBPA also provoked a significant up-regμLation of Hsp70 (50 mg/kg dw, 2.19-fold, p<0.01;100 mg/kg dw, 2.17-fold, p<0.01; 200 mg/kg dw, 2.16-fold, p<0.01) gene expression levels. Gene expression levels of CAT showed no significant variations between TBBPA treated groups and the control. 4. The toxic effects of HBCD to earthworms Eisenia fetida The growth inhibition rates of all HBCD groups were not significantly different when compared with controls. SOD and Hsp70 gene expression was up-regμLated at the concentration of 400 mg/kg dw (2.06-fold, p<0.01; 2.61-fold, p<0.01,respectively). Gene expression levels of CAT and GST showed no significant variations between HBCD treated groups and the control. 5. The contrastive analysis of toxic effects of BDE-47, BDE-209, TBBPA and HBCD on earthworms Eisenia fetida 1) Growth inhibition rates Throµgh analyzing the relative growth inhibition rates in contrast, BDE-47 was most harmfμL to the earthworms Eisenia fetida, TBBPA came second. BDE-209 and HBCD showed no toxic effects to growth of earthworms Eisenia fetida. 2) Gene expression levels Throµgh analyzing the relative gene expression levels of SOD, CAT and GST in contrast, the similar toxicity order were present as compared with that of growth inhibition. However, BDE-47, BDE-209, TBBPA and HBCD showed different pattern to influence Hsp70 gene expression. BDE-47 presented inhibition effects, but TBBPA and HBCD showed induction effects. In general, the toxicity integrating the growth inhibition and gene expression on earthworms of the four BFRs was in the order of: BDE-47>TBBPA>BDE-209, HBCD. Because of degradability of BDE-209 and the resμLts of the acute tests, it can be infer that HBCD was a rather safe BFRs to soil ecosystem. |
| 公开日期 | 2015-06-11 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/13445]  |
| 专题 | 生态环境研究中心_城市与区域生态国家重点实验室 |
| 推荐引用方式 GB/T 7714 | 徐湘博. 典型溴代阻燃剂对赤子爱胜蚓的分子生态毒性效应[D]. 北京. 中国科学院研究生院. 2014. |
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