多氯联苯在两种海洋微藻中毒性效应及富集效应的研究

摘要

通过分析2,2',3,4,4',5'-六氯联苯(PCB138)对牟氏角毛藻(Chaetoceros muelleri)和亚心形扁藻(Platymonas subcordiformis)生长的影响,以及PCB138对两种微藻超氧化物歧化酶(Superoxide dismutase,SOD)活性的影响,研究多氯联苯对海洋微藻的毒性效应,并采用气相色谱法研究了两种微藻对PCB138的生物富集效应.结果表明,PCB138对牟氏角毛藻和亚心形扁藻均有明显的毒性效应作用,对2种藻类的96 h半抑制质量浓度(96hEC50)分别为0.057 mg/和0.354 mg/L,与亚心形扁藻相比,牟氏角毛藻对PCB138更敏感,耐受性更差;低浓度的PCB138对两种微藻SOD酶活性有诱导作用,但当PCB138浓度过高时,SOD酶活性下降;两种微藻对PCB138均有明显的富集作用,随着培养时间的延长,牟氏角毛藻中富集的PCB138含量呈上升趋势,而亚心形扁藻中PCB138含量呈现先上升后下降趋势.%In order to investigate the toxicity effects of PCBs on marine microalgae, two algae species, Chaetoceros muelleri and Platymonas subcordiformis, were selected to study the effects of PCB138 on growth and SOD enzyme activities. Meanwhile, the enrichment effects of PCB138 on C. muelleri and P. subcordiformis were analyzed by gas chromatography. The results showed that PCB138 had obvious toxicity effects on the growth of C. muelleri and P. subcordiformis. The 96-h EC50 of PCB138 on C. muelleri and P. subcordiformis were 0.057 mg·L–1 and 0.354 mg·L–1, respectively, which indicated that C. muelleri showed more sensitivity and poorer tolerance to PCB138 than P. sub-cordiformis. SOD activities in two microalgae cells were greatly induced by low levels of PCB138, and reduced as the PCB138 concentrations increased above threshold values. Both of the algae species had strong capabilities to accumulate PCB138. The adsorption amount of PCB138 in C. muelleri increased with increasing cultivation time, while the amount of PCB138 adsorbed in P. subcordiformis first increased, then decreased.