摘要:
为了研究四溴联苯醚(BDE-47)对海洋桡足类的毒性效应,以太平洋真宽水蚤和日本虎斑猛水蚤为受试生物,依据急性毒性实验96 h-LC50值,设置5个浓度组和1个对照组,测定摄食率、滤水率、耗氧率、排氨率和抗氧化防御系统中SOD、GST、GPx活性以及GSH含量。结果显示:BDE-47对太平洋真宽水蚤和日本虎斑猛水蚤的96 h-LC50分别为57和851 μg·L-1,后者明显高于前者。2种桡足类在BDE-47作用下,其能量摄入和代谢均受到不同程度的诱导或抑制。太平洋真宽水蚤在中浓度(1.425 μg·L-1)下摄食率和排氨率受到促进,高浓度(5.70和11.40 μg·L-1)下耗氧率明显抑制;日本虎斑猛水蚤高浓度下(170.20 μg·L-1)摄食率受到抑制,中浓度(21.28 μg·L-1)下耗氧率受到促进,各个浓度的BDE-47对其排氨率均有明显促进作用。太平洋真宽水蚤SOD活性在BDE-47暴露96 h过程中均低于对照组(P < 0.05),受到明显抑制;GST活性随暴露时间延长先升高后降低;GSH含量和GPx活性低浓度(0.7125和1.425 μg·L-1)下随时间先升高后降低,而高浓度(5.70和11.40 μg·L-1)下则相反。日本虎斑猛水蚤SOD活性随BDE-47浓度的升高先降低后升高再降低;GST活性和GSH含量在低浓度(10.64和21.28 μg·L-1) BDE-47中与对照组相比无显著差异(P > 0.05),而高浓度(85.10和170.20 μg·L-1) BDE-47下,GST活性随时间先升高后降低,GSH含量则先降低后升高再降低;GPx活性呈现先降低后升高趋势。由此可见,BDE-47与这2种桡足类的能量摄入、代谢和抗氧化防御系统存在一定时间及剂量效应,并具有明显的物种差异性。
Abstract:
To study the toxic effects of BDE-47 on the marine copepods, Eurytemora pacifica and Tigriopus japonicas were exposed to BDE-47 for 96 h-LC50 measurement. On this basis, experiments aimed to determine the effect of BDE-47 on the ingestion, metabolism and antioxidant defense system of E. pacifica and T. japonicas were performed respectively with five different concentrations and a control group. Results showed that the 96 h-LC50 of BDE-47 were 57 μg·L-1 for E. pacifica and 851 μg·L-1 for T. japonicas. It is indicated that BDE-47 has higher toxicity to E. pacifica than T. japonicas. The ingestion and metabolism were significantly enhanced or inhibited under different concentrations of BDE-47. The ingestion and ammonia excretion rate of E. pacifica were promoted in the moderate concentration (1.425 μg·L-1), and the oxygen consumption rate was inhibited in the high concentration (5.70 and 11.40 μg·L-1). The ingestion of T. japonicas was inhibited in the high concentration (170.20 μg·L-1), while the oxygen consumption rate was promoted in the moderate concentration (21.28 μg·L-1). The ammonia excretion rate of T. japonicas was enhanced obviously. The results of 96 h exposure experiments showed that in E. pacifica, the activities of SOD were restrained throughout 96 h. The activities of GST increased at first and then decreased with the extension of exposure time. The contents of GSH and the activities of GPx were induced initially and inhibited afterwards at low level (0.7125 and 1.425 μg·L-1), and at high level (5.70 and 11.40 μg·L-1) it was on the contrary. The activities of SOD and the contents of GSH of T. japonicas were both very sensitive to BDE-47. SOD activities were inhibited first, then induced and inhibited at last with the increase of BDE-47 concentration. The activities of GST and the contents of GSH had no significant differences in comparison to control at low level (10.64 and 21.28 μg·L-1), while at high level (85.10 and 170.20 μg·L-1) GST activities were increased at first and then decreased with the extension of time, and GSH contents were inhibited first, then induced and inhibited at last. The activities of GPx were inhibited first and then induced. A certain time and dose-response was observed for BDE-47 toxicity to copepods, and had significant differences between species.
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