The joint toxicity of Penta-BDE(Pe-BDE)and heavy metals including cadmium and copper on Daphnia magna(D.magna)was evaluated on the basis of determining the 48 h survival,antioxidative enzyme responses,and lipid peroxidation.The response was classified as additive,greater than additive,or less than additive by comparing the measured“toxic units,TU”with one.Based on the survival of D.magna,less-than-additive interactions were found in most of mixtures treatments.This may be attributed to the different toxicity mechanism between Pe-BDE and metals.Cu and Cd played a greater role in toxicity than what Pe-BDE did.As for the superoxide dismutase(SOD)and catalase(CAT)activity,most response was less than additive.For the glutathione S-transferases(GST)activity,most of the greater-thanadditive responses were found in the Cu plus Pe-BDE treatments,but the additive responses occurred in Cd plus Pe-BDE treatments and binary metal treatments.For lipid peroxide levels,which were measured as malondialdehyde(MDA)levels,less-than-additive response occurred in the 50%Cd plus 50%Cu and ternary mixture treatments.Results suggested that Pe-BDE,Cd,and Cu could induce different patterns of antioxidant enzyme responses,such as antioxidant/prooxidant responses,depending on their capability to produce reactive oxygen species and antioxidant enzymes to detoxify them.
为了建立一种用Tenax萃取快速评价土壤中多溴联苯醚生物可利用性的方法,本研究以商业多溴联苯醚DE-71和DE-79中6种主要同系物(BDE-47,99,100,154,153,183)为研究对象,对不同染毒浓度的土壤用Tenax萃取6 h,并将Tenax萃取结果与土壤-蚯蚓(赤子爱胜蚓Eisenia foetida)生物富集试验结果进行了比较。结果表明,单位质量土壤中被Tenax萃取出的PBDEs的质量随土壤中PBDEs浓度的增大而增加,随各同系物lgKow值的增大而降低。6 h Tenax萃取的富集因子TSAF6与蚯蚓的生物富集因子BSAF之间具有良好的相关性,表明6 h Tenax萃取能够有效表征土壤中PBDEs的生物可利用性。
