氧化石墨烯对邻苯二甲酸二丁酯藻毒性的影响

以海洋微藻青岛大扁藻(Platymonas helgolanidica var.tingtaoensis)为受试对象,研究了氧化石墨烯(graphene oxide,GO)与邻苯二甲酸二丁酯(dibutyl phthalate,DBP)单独及共同对青岛大扁藻的急性毒性效应,考察了藻细胞的生长状况,光合色素产量,细胞通透性,氧化应激指标及扫描电镜,以探讨GO的加入对DBP藻毒性的影响.结果表明,低浓度GO(0.1~10 mg·L~(-1))对青岛大扁藻的藻密度和叶绿素产量无明显影响,但藻细胞通透性随GO浓度升高显著增加(P0.05),10mg·L~(-1)时达到空白组的2.2倍.DBP对青岛大扁藻的EC50,96 h为(11.14±0.80)mg·L~(-1),其毒性远大于GO(EC50,96 h大于100mg·L~(-1)).1 mg·L~(-1)GO的加入使DBP的EC50,96 h降低到(4.93±2.14)mg·L~(-1),低浓度GO对DBP藻毒性表现出一定的增强作用.1 mg·L~(-1)的GO加入时,对低浓度DBP组(0.1~2 mg·L~(-1))的藻密度、叶绿素产量、细胞通透性水平没有显著性影响,但加剧了高浓度DBP组(4 mg·L~(-1))对藻密度、叶绿素产量的抑制,使单个藻细胞内ROS和SOD平均增加了21%和7%.扫描电镜结果发现GO对藻细胞具有覆盖,包裹及聚集作用,这些可能是DBP藻毒性增强的主要原因.该结果为揭示新型污染物碳纳米材料对海洋生物的风险提供了数据支持.

Effect of Graphene Oxide on Algal Toxicity of Dibutyl Phthalate

Marine microalgae, Platymonas helgolondica var. tsingtaoensis, were used as experimental subjects to study the acute toxic effects of graphene oxide (GO) and dibutyl phthalate (DBP), both individually and together. The growth of algae cells, production of photosynthetic pigments, cell permeability, and oxidative stress were investigated. The effects of GO on the algal toxicity of DBP were evaluated. The results showed that low concentrations of GO (0.1-10 mg·L^-1) had no significant effect on algae density and chlorophyll production of Platymonas helgolondica var. tsingtaoensis (P<0.05). However, the algae cell permeability increased significantly with GO concentration (P<0.05) and reached 2.2 times that of the control group at 10 mg·L^-1. The EC_{50, 96 h} value of DBP for Platymonas helgolondica var. tsingtaoensis was (11.14±0. 80) mg·L^-1, which, in terms of toxicity, was much higher than that of GO (EC_{50, 96 h}>100 mg·L^-1). At a GO concentration of 1 mg·L^-1, the EC_{50, 96 h} value of DBP decreased to (4.93±2.14) mg·L^-1, showing that low concentrations of GO enhanced the algae toxicity of DBP. When 1 mg·L^-1 of GO was added, low concentrations of DBP (0.1-2 mg·L^-1) did not have any significant effect on algae density, chlorophyll production, cell permeability, ROS, and SOD. However, the inhibitory effects of high concentrations of DPB (4 mg·L^-1) on algae density and chlorophyll production were enhanced by GO, thereby increasing the average ROS and SOD in algae cells by 21% and 7%, respectively. SEM images showed that GO was the primary factor responsible for increasing the coverage and packing of, and the aggregation effect on, algae cells, which could be the reasons for the increased toxicity of DBP. The results of our study can provide data to reveal the risk of novel carbon nanomaterial pollutants to marine organisms.