【作者】 范灿鹏；

【导师】 聂湘平；

【作者基本信息】 暨南大学 ， 环境科学， 2011， 硕士

【摘要】 多溴联苯醚(Polybrominated diphenyl ethers, PBDEs)是一种添加型阻燃剂,广泛应用于电子工业和防火材料的生产。其中,2,2′,4,4′-四溴联苯醚(2,2’,4,4’-tetrabromodiphenyl ether, BDE-47)是存在于环境样本和人体组织中最主要的PBDEs同系物之一。广东省汕头市贵屿镇是国内乃至世界最大的电子废物拆解处理集散地,调查表明该地环境中大量残留PBDEs。羊角月牙藻(Selenastrum capricormutum)、大型溞(Daphnia magna)、剑尾鱼(Xiphophorus helleri)分别是水生态系统中的浮游植物、浮游动物和鱼类三个营养级上的代表生物,本研究以这三种水生生物为实验生物,研究BDE47和贵屿镇的环境样品浸出液对水生生物的毒性效应。研究结果表明,BDE-47对羊角月牙藻96 h EC50为2.18 mg-L-1,属于中毒。随着BDE-47浓度的增大,叶绿素a含量下降,呈现显著的剂量-效应关系。BDE-47对GSH的影响较弱,总体呈抑制状态。随着BDE-47浓度的增加,GST、APX和CAT活性均呈现出先诱导后抑制的现象,而MDA含量则先下降后逐渐上升。SOD活性整体受到显著抑制。APX和SOD活性响应敏感且变化稳定,适合作为BDE-47对羊角月牙藻暴露的生物标记物。BDE-47对大型溞的48 h LC50为1.04 mg·L-1,属于高毒物质。随着BDE-47浓度的增加,GST和SOD活性均呈现出低浓度诱导高浓度抑制的现象。SOD和GST均表现出一定的敏感性,但GST相对于SOD来说,对BDE-47暴露更敏感。从BDE-47慢性毒性实验结果来看,大型溞体长均低于空白对照组,低浓度组中大型溞繁殖能力受到了抑制作用,而高浓度组中大型溞繁殖能力上升,其中第一次繁殖个体数和生殖总数是表征BDE-47慢性毒性的最灵敏参数。BDE-47对剑尾鱼毒性96 h LC50为2.75 mg-L-1,属于高毒物质。GST和EROD活性在0.02 mg·L-1 BDE-47污染胁迫下即被显著诱导；72 h和168 h后,GSH含量均受到抑制,168 h时达到最低值；随着BDE-47暴露浓度的增加,CAT活性呈现先上升后下降的变化规律,而MDA含量则先下降后逐渐上升。其中,MDA和EROD响应较为敏感,在作为BDE-47对剑尾鱼暴露的生物标记物方面有较好的应用前景。羊角月牙藻暴露在采自于贵屿镇电子垃圾拆卸地的土壤及底泥浸出液后,羊角月牙藻GSH和MDA含量影响不大；随着底泥和土壤浸出液浓度的增加,APX和SOD活性均上升；CAT活性均在土壤和底泥浸出液最高浓度100%处最低,受到极显著抑制：经土壤浸出液暴露后,GST活性受到抑制,而经底泥浸出液暴露的羊角月牙藻GST活性随浓度增加先下降后上升。APX和SOD活性响应敏感且变化稳定,在作为环境样品暴露的生物标记物方面有较好的应用前景。从浸出液对大型溞的慢性毒性实验结果来看,各浓度组的大型溞繁殖能力与空白组相比均受到了较显著抑制,具体体现在产仔胎数和生殖总数两个指标上。浸出液暴露24 h后,SOD活性先诱导后抑制,48 h时SOD活性无显著性变化；经浸出液暴露的大型溞体内GST活性总体受到抑制,而MDA含量均高于空白对照组。GST和MDA响应敏感且变化稳定,适合作为环境样品暴露的生物标记物。更多还原

【Abstract】 Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants in numerous electronic products, and 2,2’,4,4’-tetrabromodiphenyl ether (BDE-47) is one main homolog of PBDEs which exists widely in environmental samples and human tissues. Guiyu, a small town which located at Shantou district in the South China, is the largest dissembling and processing center of electronic waste in China and even the world, where PBDEs are detected extensively in various environmental medium. Selenastrum capricormutum, Daphnia magna and Xiphophorus helleri are the representative organisms of different trophic levels in aquatic ecosystem. The toxic effects of BDE-47 and the lixivium of the environmental samples from Guiyu on Selenastrum capricormutum, Daphnia magna, Xiphophorus helleri were studied in the present study.The results showed that BDE-47 was middle-toxic to Selenastrum capricornutum, the 96h EC50 was 2.18 mg·L-1 in BDE-47 exposure. With the increase of exposure concentration of BDE-47, the chlorophylla a content decreased gradually in Selenastrum capricornutum cells, the content of GSH had slight variances among different treatments groups, and GST, APX and CAT activity increased firstly and then inhibited gradually. On the contrary, MDA reduced firstly and then increased steadily. The activity of SOD was almost suppressed continuously. Both APX and SOD were sensitive and suitable to be used as potential biomarkers for the exposure of BDE-47 compared with the other parameters.BDE-47 was high-toxic for Daphnia magna, the 48h LC50 was 1.04 mg·L-1. With the increase of exposure concentration of BDE-47, the activity of SOD and GST were induced firstly and then inhibited. Both SOD and GST expressed sensibility, but GST is comparatively more sensitive than SOD for the BDE-47 exposure. The chronic test of BDE-47 to Daphnia magna indicated that the length was inhibited, the fecundity was inhibited at the low concentration groups, however, the contrary performance were observed at high concentration groups. The eggs production number of the first time and the total egg production number are the most sensitive parameters for the chronic test of BDE-47.BDE-47 was high-toxic for Xiphophorus helleri. The 96h LC50 was 2.75 mg·L-1. GST and EROD were induced significantly when BDE-47 level was at only 0.02 mg·L-The content of GSH was decreased after 72h and 168h, and reached the lowest value after 168h. With the increase of exposure concentration of BDE-47, CAT activity was induced firstly and then inhibited. On the contrary, it was reduced firstly and then increased gradually for MDA. MDA and EROD were the more sensitive measured parameters and more suitable be used as potential biomarkers for BDE-47 exposure.The contents of GSH and MDA of tested aglae had slight variances among different treatments groups with lixivium derived from Guiyu soil and sediment samples. With the increase of exposure concentration of the lixivium, both SOD and GST activity were increased. The activity of CAT reached the lowest at the concentration of 100% of the lixivium of the soil and sediment. The activity of GST was almost suppressed continuously after the exposure of the the lixivium of the sediment, but the activity of GST was reduced firstly and then increased with the concentration increased of the lixivium of the sediment. APX and SOD were sensitive and suitable to be used as candidates potential biomarkers for the exposure of BDE-47 compared with the other parameters.The chronic test of the lixivium to Daphnia magna indicated that the fecundity were inhibited at all concentration groups, and was embodied in the parameters of the frequency of production and the total egg production number. SOD was increased firstly and then reduced after the 24h exposure of the lixivium, and there was no significant change after 48h exposure. GST was suppressed continuously after the exposure of the lixivium. On the contrary, the content of MDA was above the control group. Both GST and MDA were sensitive and suitable to be used as potential biomarkers for the exposure of BDE-47 compared with the other parameters.更多还原