纳米材料—镉复合体对水生生物的毒性效应

发布时间：2018-05-21 11:11

  本文选题：纳米材料-镉复合体 + 急性毒性　； 参考：《天津工业大学》2017年硕士论文

【摘要】：纳米材料由于其具有微孔结构易与重金属结合的性质,因而被广泛应用于水体和土壤重金属污染修复。但吸附重金属的纳米材料是否安全还有待考证。因此,本论文以重金属Cd~(2+)为典型污染物,以纳米二氧化锰和纳米羟基磷灰石为吸附剂,从个体水平,组织水平和分子水平系统研究Cd~(2+)与纳米材料-镉复合体(Nano-Cd)对大型蚤和斑马鱼的毒性效应和致毒机制。主要研究结果如下:急性毒性实验表明,Cd~(2+)和Nano-Cd复合体对大型蚤的毒性大小顺序为Cd~(2+)nMnO_2-CdnHAp20-CdnHAp40-Cd。根据 Commission of the European Communities(ECC)对大型蚤的毒性分类标准,Cd~(2+)对大型蚤的毒性等级为极高毒;nMnO_2-Cd、nHAp20-Cd和nHAP40-Cd对大型蚤的毒性等级为有毒。参照 Organisation for Economic Co-operation and Development(OECD)对大型蚤的毒性分类标准,Cd~(2+)对大型蚤的毒性等级为急性毒性Ⅰ;nMnO_2-Cd、nHAp20-Cd和nHAp40-Cd对大型蚤的毒性等级为急性毒性Ⅱ。亚急性毒性实验表明,大型蚤体内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)和抗超氧阴离子自由基(ASA)酶活性随着Cd~(2+)和Nano-Cd复合体浓度的增加,呈现先上升后下降的趋势。在中、低暴露浓度下,大型蚤体内的SOD、CAT、POD酶活性均着随浓度的升高而增大。而在高浓度时,体内的SOD、CAT、POD和ASA的酶活性均有所降低。MDA含量随着暴露浓度的增加而增加,说明机体内膜系统遭到破坏。急性毒性实验表明,Cd~(2+)和Nano-Cd复合体对斑马鱼的毒性大小顺序为Cd~(2+)nMnO_2-CdnHAp20-CdnHAp40-Cd,48h-LC50 分别为 0.57mg/L、1.26mg/L、1.33mg/L和1.44mg/L。根据ECC对斑马鱼的毒性分类标准,Cd~(2+)、nMnO_2-Cd、nHAp20-Cd和nHAp40-Cd对斑马鱼的毒性等级为有毒。而OECD评定Cd~(2+)、nMnO_2-Cd、nHAp20-Cd和nHAp40-Cd对斑马鱼的毒性等级为急性毒性Ⅱ。亚急性毒性实验表明,斑马鱼肝脏中的SOD、ASA、CAT和POD酶活性随着暴露浓度的增加,与对照相比,整体呈现先上升后下降的趋势,而MDA含量随着暴露浓度的增加而增加。根据彗星实验可知,Cd~(2+)和Nano-Cd均能对斑马鱼肝脏DNA造成损伤,且随着暴露浓度的增加,损伤程度越严重。在同一暴露浓度下,与Nano-Cd相比,Cd~(2+)造成的DNA损伤更严重;而对于Nano-Cd复合体而言,nMnO_2-Cd比nHAp-Cd造成DNA损伤程度更严重。因此,对水生生物而言,纳米材料作为吸附剂是不安全的,吸附重金属后应将其从水体中去除。
[Abstract]:Nanomaterials are widely used in the remediation of heavy metal pollution in water and soil because of their micropore structure and the properties of heavy metals. However, the safety of heavy metal adsorbed nanomaterials remains to be verified. Therefore, in this thesis, the heavy metal Cd~(2 was used as the typical pollutant, and the nanometer manganese dioxide and hydroxyapatite were used as adsorbents. The toxic effects and mechanism of Cd~(2 and Nano-CD on flea Magna and zebrafish were systematically studied at the tissue and molecular levels. The main results were as follows: the acute toxicity test showed that the toxicity of the Nano-Cd complex to fleas was in the order of Cd~(2 nMnO _ 2-CdnHAp20-CdnHAp40-Cd. According to the toxicity classification standard of Commission of the European Communitiesus Commission of the European to Daphnia Magnus, the toxicity grade of Commission of the European to Daphnia Magna is very high. The toxicity grade of nHAP40-Cd to Daphnia Magna is very high, and the toxicity grade of nHAP40-Cd is toxic to Daphnia Magnus. According to the toxicity classification standard of Organisation for Economic Co-operation and development Organisation for Economic Co-operation and to Daphnia Magnus, the acute toxicity grade 鈪，

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