为了探讨环境激素类物质邻苯二甲酸二乙酯(DEP)和壬基酚(NP)对海洋微藻的联合毒性效应,选取杜氏盐藻(Dunaliellasalina)为受试生物,以环境激素对杜氏盐藻单一暴露的96hEC50的毒性效应作为一个毒性单位(IU),采用毒性单位法比较研究了DEP和NP单-暴露以及两者以三种不同混合比例(毒性单位比:1:1、1:4和4:1)暴露对杜氏盐藻的细胞生长、叶绿体色素含量、可溶性蛋白含量、SOD活性以及最大光能转化效率(Fv/Fm)的影响。实验结果表明:DEP和NP单-暴露对杜氏盐藻的96hEC50分别为69.54mg/L和1.47mg/L,两种环境激素对杜氏盐藻均有抑制作用,且NP较DEP对杜氏盐藻的毒性更强。DEP和NP联合暴露较单一暴露对杜氏盐藻的细胞生长、叶绿体色素和可溶性蛋白的合成有较强的抑制作用,两种环境激素在毒性单位比为1:1、1:4、4:1三个比例水平上的联合毒性效应均表现为协同效应,其中比例为1:1的协同效应最强。
Combined toxic effect of diethylphthalate (DEP) and nonylphenol (NP)on the growth ofDunaliella salina was evaluated by taking the 96h EC50 as one toxic unit (TU). Cell density, protein content, chloroplast pigment content, SOD activity, and maximal photochemical efficiency of PSII (Fv/Fm) of D. salina were examined after the single and three different combined exposure for 96h (toxic unit proportion 1:1,1:4, 4:1).The results showed that both DEP and NP inhabited the growth of D. salina. Moreover, the toxic effect of simultaneous exposure was more significant than single exposure of the two chemicals. The values of 96h ECS0 of DEP and NP on D. salina were 69.54 mg/L and 1.47 rag/L, respectively. The single toxic effect as well as combined toxic effect on the biomass, soluble protein content, chloroplast pigment, and SOD activity content of D. salina was detected based on the different toxicity unit proportions. Synergetic effect was observed for the toxicity of DEP and NP in the three toxicity unit proportions, which was more obvious in the proportion of 1:1.