菲和芘单一及复合污染对蚯蚓抗氧化酶活性和丙二醛含量的影响

Effect of single and combined pollution of Phe,Pyr on SOD、CAT activities and MDA content of Eisenia Foetida in soils

采用自然土壤法,以蚯蚓体内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和丙二醛(MDA)含量为指标,探讨了不同剂量、不同暴露时间菲(Phe)和芘(Pyr)单一及复合污染胁迫对蚯蚓的毒性效应.结果表明,菲和芘单一作用时,SOD活性均表现为低剂量激活,高剂量抑制;而MDA含量在暴露2d内明显增加,第14d时与对照基本一致;对于CAT活性,菲单一作用时呈现先上升后下降的变化规律,而芘单一作用时未见明显的变化规律.菲和芘复合作用时,SOD活性受到显著抑制,而MDA含量于暴露28d时达到最大值,复合胁迫促进了蚯蚓的膜脂过氧化作用.在0.5mg·kg-1菲作为背景与不同剂量芘复合时,菲和芘复合污染时的CAT活性出现明显波动,低剂量芘复合污染的CAT活性呈现先上升后下降的变化规律;而当菲含量为2.5mg·kg-1时,复合污染时的CAT活性总体呈逐渐上升趋势.复合污染胁迫时污染物剂量变化和不同污染物组合会对蚯蚓产生更趋严重和复杂的氧化胁迫效应.

In this study,a bioassay was conducted to investigate the effects of single and compound application of phenanthrene（Phe） and pyrene（Pyr） in soil on superoxide dismutase（SOD） and catalase（CAT） activities and the level of malondialdehyde（MDA） in earthworms（Eisenia Foetida）.Different changes in SOD,CAT activity and MDA content in the tested earthworms were observed for application of Phe or Pyr alone.SOD activity showed a concentration-dependent effect with the PAHs：it increased in the low concentration group,while it decreased in the high concentration group compared to the controls.MDA content in the earthworms varied over the 28 day exposure time.When only Phe was applied to the soil,CAT activity in earthworms varied over the 28 day exposure time.No obvious effects of Pyr on CAT activity were observed in this study.When soil was treated with multiple concentrations of Pyr and a fixed concentration of Phe,SOD activity was restrained significantly.After 28 days of exposure the MDA content of all groups reached their maximum,and the combined stress could promote lipid peroxidation in the earthworms.When the soil was treated with 0.5 mg · kg-1 Phe,lower Pyr additions caused the CAT activity to vary over the 28 day exposure time.The application of 2.5 mg · kg-1 Phe in soil caused an increase of CAT in the presence of Pyr.The effects of combined Phe and Pyr pollution differed among the various treatments and were closely related to the applied PAHs doses.The results of this study indicated that compound treatment of Phe and Pyr caused more serious oxidative threat to the tested earthworms.