2,2’,4,4’-四溴二苯醚(BDE-47)对大型溞(Daphnia magna)的毒性效应

2,2’,4,4’-四溴二苯醚(BDE-47)在水体及各种水生生物(鱼类、海洋哺乳动物以及水生无脊椎动物)中被广泛检出,但BDE-47对水生无脊椎动物毒性效应的研究还处于起步阶段。以大型溞(Daphnia magna)为受试生物,通过急性(48h)和慢性(21d)毒性暴露实验,考察了BDE-47对大型溞活动抑制率、心率、产仔情况和酶活性等指标的影响。结果显示,BDE-47对大型溞活动抑制率的48h-EC50为112.5μg.L-1;高浓度(>100μg.L-1)BDE-47显著诱导提高大型溞的心率。21d慢性暴露实验中,8μg.L-1处理组中大型溞全部死亡;其他各浓度处理组(0.5、1、2、4μg.L-1)中,母溞第1胎产仔时间延后,第1胎子代数量减少,总产仔数量大幅减少,这表明大型溞的繁殖能力受到抑制。BDE-47在一定程度上抑制了母溞胆碱酯酶(ChE)和谷胱甘肽硫转移酶(GST)的活性,大型溞体内的代谢机制没有被诱导,神经活性虽被抑制,但抑制率不高。BDE-47大幅诱导过氧化氢酶(CAT)的活性,并呈现一定的剂量效应关系,相对于ChE和GST,CAT对BDE-47暴露更为敏感,可作为BDE-47对大型溞慢性暴露毒性效应的潜在生物标志物。

Toxic Effects of 2,2',4,4'-Tetrabromodiphenyl Ether(BDE47)to Daphnia magna

2,2',4,4'-tetrabromodiphenyl ether(BDE-47) are widely detected in water and aquatic organisms(fish,marine mammals and aquatic invertebrates),however,there is still lack of research on its toxic effects on aquatic invertebrates.The acute(48 h) and chronic(21 d) tests were conducted to explore the effects of BDE-47 on Daphnia magna with several endpoints as immobilization rate,heart rate,reproduction rate,and the activities of ChE,GST and CAT.Results showed that the 48 h-EC50 value of BDE-47 on the immobilization of D.magna was 112.5 μg·L-1.An increase in the heart rate of D.magna was significantly induced by BDE-47 at high concentrations(>100 μg·L-1).In chronic test(21 d),no survival of D.magna in 8 μg·L-1 BDE-47 exposure group was observed.In the other BDE-47 exposure groups(0.5,1,2,4 μg·L-1),the first birth was delayed,and the first litter size as the total number of offspring per maternal D.magna were reduced.It was indicated that the fecundity of D.magna was inhibited by BDE-47.The activities of cholinesterase(ChE) and glutathione-S-transferase(GST) of maternal daphnids were inhibited by BDE-47,impling that the metabolism of D.magna was not induced by BDE-47,while neuro-activity was inhibited by BDE-47 in a relatively low extent.Catalase(CAT) activity of maternal D.magna was significantly induced by BDE-47 in a dose-response manner.CAT was more sensitive to BDE-47 than GST or ChE.The activity of CAT could become a potential biomarker to chronic BDE-47 exposure.