Toxic Effect In Scenedesmus Obliquus Impacted By Nano-alumina Alone And Combined With Butachlor

Nano-alumina（Al₂O₃ NPs）is a new alumina material,which inherits the advantages of macro scopical materials and exhibits new excellent properties because of nanometer level size.Surface characters of Al₂O₃ NPs impact environmental fates and toxic effects.The investments of surface-modified nanomaterial and composite materials were increasing these years.However,their different effects on organisms were still slurred.The aim of this experiment was to study the different toxic effects on Scnedesmus obliquus（S.obliquus）of Al₂O₃ NPs due to the crystalline form and surface-modification,the joint effect with butachlor and the interaction with acid phosphatase.The results were as follows:（1）Growth inhibition effects of three kinds of Al₂O₃ NPs（γ-phase,α-phase and α-phase hydrophobic（Lauric acid）modification）present on S.obliquus,were of dosage-dependence;The EC50（72 h）of γ-phase,α-phase and hydrophobic modification were 53.88 mg/L,93.55 mg/L and 48.11 mg/L,respectively,and their inhibition effects were significantly higher than the micron scale particles.All the Al₂O₃ NPs led to different degrees of oxidative stress,cells deformation/wilt.And aggregation between Al₂O₃ NPs and S.obliquus greatly affected the toxicity.The release ion Al3+ was not the major factor.（2）The joint effect of Al₂O₃ NPs and butachlor on S.obliquus was evaluated: The concentration of Al₂O₃ NPs was fixed at 12.5 mg/L,with the increasing of the butachlor concentration from 0.00001 mg/L to 0.00313 mg/L,the mixed system shown the antagonism to the algae at low concentration and synergism at high concentration;the combined effects of micron-grade particles and butachlor were antagonism and additive effect;the Al₂O₃ NPs could not affect the butachlor degradation,but absorb the butachlor.It was probably the main reason for the combined effects.（3）The interaction between Al₂O₃ NPs and acid phosphatase（ACP）was studied.The results suggest that the complex formation lead to a static quenching of ACP.And the ACP acitivity was inhibited even in such complex crude laccase of S.obliquus.