Cd-HA-TiO_2联合胁迫对小球藻致毒效应的研究  

Combined Toxicological Effects of Cadmium,Humic Acid and TiO_2 on Chlorella

作　　者：梁斯韵 康园[1] 曾丽璇[1] 张秋云[1] 罗继文[1] 

机构地区：[1]华南师范大学化学与环境学院,广州510006

出　　处：《华南师范大学学报（自然科学版）》2017年第6期52-59,共8页Journal of South China Normal University(Natural Science Edition)

基　　金：国家自然科学基金项目(41301563);广东省科技计划项目(2014A020216036)

摘　　要：以小球藻为受试生物,研究Cd-HA-TiO_2联合暴露体系对小球藻的毒性作用.实验结果表明,Cd单独作用、Cd-HA和Cd-TiO_2联合作用下,Cd的96h-EC50分别为:0.166、0.185~0.207和0.185~0.199 mg/L,以上结果说明当HA或TiO_2存在情况下,可以降低Cd对小球藻的生物毒性,这主要是由于HA或TiO_2可以吸附水中Cd,降低体系中自由金属离子的质量浓度,进而减弱了Cd的生物毒性.但在Cd-HA-TiO_2三者联合作用下,Cd的96h-EC50降低到0.063~0.089 mg/L,表明当HA、TiO_2同时存在时,Cd对小球藻的生物毒性显著增强.通过检测暴露后的丙二醛(MDA)、过氧化氢酶(CAT)和超氧化物(KAT)水平,发现Cd-HA-TiO_2联合作用时,小球藻的CAT水平显著高于其他暴露条件(P<0.05);细胞内Cd分布实验结果显示三者联合暴露显著促进了小球藻细胞内的Cd的生物累积量(P<0.05).因此,小球藻的氧化性损伤(CAT水平)和Cd的生物积累水平可能解释了三者联合暴露导致Cd毒性显著增强的原因.Chlorella was selected to test the combined toxicological effects of cadmium( Cd),humic acid( HA) and TiO_2. The results showed that the 96 h-EC50 of Cd,Cd-HA and Cd-TiO_2 was 0.166,0.185 ~ 0.207 and 0.185 ~ 0.199 mg/L,respectively,indicating that the toxicity of cadmium was attenuated in the presence of HA or TiO_2. This was mainly due to the reduction of free Cd ion through combination of HA and TiO_2. However,the 96 h-EC50 of Cd-HA-TiO_2 was decreased to 0.063 ~ 0.089 mg/L,indicating that the toxicity of cadmium was significantly increased in the presence of HA and TiO_2. Chlorella showed the highest CAT level after exposure to Cd-HA-TiO_2 compared to other treatments. In addition,the bio-accumulation level of Cd was the highest after exposure to Cd-HA-TiO_2. This may explain the highest toxicity observed in the Cd-HA-TiO_2 exposure group.

关 键 词：小球藻 联合毒性 二氧化钛 腐殖酸 镉 

分 类 号：X171.5[环境科学与工程—环境科学]