蚯蚓—土壤系统中纳米零价铁和十溴联苯醚的毒性效应研究
发布时间：2018-08-09 13:07
【摘要】：十溴联苯醚(BDE209)是电子垃圾拆解场地环境中典型的污染物。近年来,纳米零价铁(nZVI)在污染场地修复中的应用越来越广泛。两种化学品联合作用对土壤生物产生的毒性效应正成为研究热点。本文选取BDE209和nZVI作为研究对象,针对污染物暴露对土壤系统中蚯蚓(赤子爱胜蚓)的毒性效应开展研究。主要结果如下:(1)nZVI与BDE209复合胁迫下,不同浓度nZVI添加能影响BDE209在蚯蚓体内的富集与转化。在暴露中后期(14和28天),低浓度(100 mg kg-1)的nZVI胁迫能促进蚯蚓表皮对BDE209(10 mg kg-1)的吸收,而中高浓度(500 mg kg-1和1000 mg kg-1)的nZVI胁迫则抑制BDE209在蚯蚓体内的富集。此外,GC-MS分析表明BDE209在蚯蚓体内可降解为低溴代联苯醚(BDE208、BDE207、BDE206、BDE203、BDE153、BDE99和BDE28等),且nZVI共存时低溴代联苯醚能被羟基自由基攻击,生成羟基化产物。(2)土壤法急性毒性实验中,暴露14天后,所有nZVI处理组蚯蚓的死亡率均低于50%。亚急性毒性实验表明,100mgkg-1 nZVI显著抑制蚯蚓的生长、呼吸和繁殖行为,并且提升了其回避效应(P0.05)。此外,10mgkg-1 BDE209联合添加显著降低了蚯蚓生理指标的活性(P0.05)。(3)nZVI胁迫下,短期暴露(7天)后,蚯蚓超氧化物歧化酶(SOD)活性显著升高(P0.05),但是在暴露后期(28天),SOD活性在一定程度上降低(P0.05)。而过氧化氢酶(CAT)活性在暴露中前期(7和14天)诱导效应不明显(P0.05),然而在 21 天后被显著诱导(P0.05)。nZVI(100mgkg-1)和 BDE209(10mgkg-1)联合胁迫下蚯蚓体内活性氧自由基(ROS)的累积会导致SOD、CAT活性的扰动和丙二醛(MDA)含量的升高(P0.05),进一步说明脂质过氧化的发生。(4)nZVI和BDE209胁迫下,蚯蚓繁殖基因ANN表达水平有显著的下调效应(P0.05),且符合剂量-效应关系。线性回归结果表明,蚯蚓体内铁含量、蚯蚓繁殖率及相应的繁殖基因转录水平间相关性较好(R0.80)。总体上看,蚯蚓体内ROS、呼吸行为和繁殖基因可能是比较敏感的响应指标。
[Abstract]:Decabromodiphenyl ether (BDE209) is a typical pollutant in the environment of electronic waste dismantling site. In recent years, nano-zero-valent iron (nZVI) has been widely used in remediation of contaminated sites. The toxic effect of two chemicals on soil organisms is becoming a hotspot. In this paper, BDE209 and nZVI were selected to study the toxic effects of pollutant exposure on earthworms in soil system. The main results were as follows: (1) under the compound stress of nZVI and BDE209, the enrichment and transformation of BDE209 in earthworm were affected by different concentrations of nZVI. At the middle and late stage of exposure (14 and 28 days), nZVI stress at low concentration (100mg kg-1) promoted the absorption of BDE209 (10 mg kg-1) by earthworm epidermis, while nZVI stress at medium and high concentrations (500mg kg-1 and 1000 mg kg-1) inhibited the accumulation of BDE209 in earthworm. In addition, GC-MS analysis showed that BDE209 could be degraded into low brominated diphenyl ethers (BDE208H, BDE207, BDE206, BDE203, BDE153, BDE99, BDE28, etc.) in earthworm. When nZVI coexisted, low brominated diphenyl ethers could be attacked by hydroxyl radical and formed hydroxylation products. (2) in acute toxicity experiment of soil method, 14 days after exposure, The mortality of earthworms in all nZVI treatment groups was lower than that in 50. Subacute toxicity test showed that 100mgkg-1 nZVI significantly inhibited the growth, respiration and reproduction of earthworm, and enhanced its avoidance effect (P0.05). In addition, the addition of 10 mg kg ~ (-1) BDE209 significantly decreased the activity of earthworm physiological index (P0.05). (_ 3) under nZVI stress. After short-term exposure (7 days), the (SOD) activity of earthworm superoxide dismutase increased significantly (P0.05), but the activity of superoxide dismutase (SOD) decreased to a certain extent (P0.05) at the late stage of exposure (28 days) (P0.05). However, the activity of catalase (CAT) was not significantly induced in the early stage (7 and 14 days) of exposure (P0.05), but it was significantly induced after 21 days of exposure (P0.05) .nZVI (100mgkg-1) and BDE209 (10mgkg-1) induced the accumulation of active oxygen free radical (ROS) in earthworm. Disturbance and the increase of malondialdehyde (MDA) content (P0.05) further explained the occurrence of lipid peroxidation. (4) under nZVI and BDE209 stress, The ANN expression level of earthworm reproductive gene was significantly down-regulated (P0.05), and was in accordance with the dose-effect relationship. The results of linear regression showed that the iron content in earthworm, the fecundity rate of earthworm and the transcriptional level of the corresponding reproductive gene were well correlated (R0.80). In general, ros, respiratory behavior and reproductive genes in earthworms may be more sensitive.
【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;X171.5
[Abstract]:Decabromodiphenyl ether (BDE209) is a typical pollutant in the environment of electronic waste dismantling site. In recent years, nano-zero-valent iron (nZVI) has been widely used in remediation of contaminated sites. The toxic effect of two chemicals on soil organisms is becoming a hotspot. In this paper, BDE209 and nZVI were selected to study the toxic effects of pollutant exposure on earthworms in soil system. The main results were as follows: (1) under the compound stress of nZVI and BDE209, the enrichment and transformation of BDE209 in earthworm were affected by different concentrations of nZVI. At the middle and late stage of exposure (14 and 28 days), nZVI stress at low concentration (100mg kg-1) promoted the absorption of BDE209 (10 mg kg-1) by earthworm epidermis, while nZVI stress at medium and high concentrations (500mg kg-1 and 1000 mg kg-1) inhibited the accumulation of BDE209 in earthworm. In addition, GC-MS analysis showed that BDE209 could be degraded into low brominated diphenyl ethers (BDE208H, BDE207, BDE206, BDE203, BDE153, BDE99, BDE28, etc.) in earthworm. When nZVI coexisted, low brominated diphenyl ethers could be attacked by hydroxyl radical and formed hydroxylation products. (2) in acute toxicity experiment of soil method, 14 days after exposure, The mortality of earthworms in all nZVI treatment groups was lower than that in 50. Subacute toxicity test showed that 100mgkg-1 nZVI significantly inhibited the growth, respiration and reproduction of earthworm, and enhanced its avoidance effect (P0.05). In addition, the addition of 10 mg kg ~ (-1) BDE209 significantly decreased the activity of earthworm physiological index (P0.05). (_ 3) under nZVI stress. After short-term exposure (7 days), the (SOD) activity of earthworm superoxide dismutase increased significantly (P0.05), but the activity of superoxide dismutase (SOD) decreased to a certain extent (P0.05) at the late stage of exposure (28 days) (P0.05). However, the activity of catalase (CAT) was not significantly induced in the early stage (7 and 14 days) of exposure (P0.05), but it was significantly induced after 21 days of exposure (P0.05) .nZVI (100mgkg-1) and BDE209 (10mgkg-1) induced the accumulation of active oxygen free radical (ROS) in earthworm. Disturbance and the increase of malondialdehyde (MDA) content (P0.05) further explained the occurrence of lipid peroxidation. (4) under nZVI and BDE209 stress, The ANN expression level of earthworm reproductive gene was significantly down-regulated (P0.05), and was in accordance with the dose-effect relationship. The results of linear regression showed that the iron content in earthworm, the fecundity rate of earthworm and the transcriptional level of the corresponding reproductive gene were well correlated (R0.80). In general, ros, respiratory behavior and reproductive genes in earthworms may be more sensitive.
【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;X171.5
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