Toxic Effects Of Nano-Fe₂O₃ On Algae And Ecological Risk Assessment

In this study,nanosized hematite??-Fe₂O₃?and nano-magnetic iron oxide??-Fe₂O₃?were used as experimental materials.And scenedesmus obliquus and anabaena were used as test organisms.And laboratory experiments were performed under different concentrations of?-Fe2O3 and?-Fe2O3.By measuring CAT activity,MDA content,SOD activity,chlorophyll a content and free radical content,this study on the Effect of Scenedesmus obliquus and Anabaena oxidative damaged with different concentrations of nanosized hematite.Ecological risk assessment of?-Fe2O3 and?-Fe2O3 was carried out using the Integrated Biomarker Index?IBR?method.The experimental results are as follows.1)Scenedesmus obliquus and Anabeana were exposed to the?-Fe₂O₃ and?-Fe₂O₃.The CAT activity of Scenedesmus obliquus,the CAT vitality of Anabeana,the SOD activity of Anabeana,and the Chlorophyll a content of Anabeana were firstly induced and then inhibited.The MDA content of Scenedesmus obliquus,the SOD activity of Scenedesmus obliquus,the free radical content of Scenedesmus obliquus,the chlorophyll a content of Scenedesmus obliquus and the free radical content of Anabaena were induced and re-inhibited after induction.The MDA content of Anabaena was firstly were inhibition and re-induction after inhibition.2)Under the exposure conditions of?-Fe₂O₃ and?-Fe₂O₃,the chlorophyll a of Scenedesmus obliquus was induced.The chlorophyll a content in the experimental group was significantly higher than that in the blank group.The effects of two nanometer iron oxide on CAT activity,MDA content,SOD activity and free radical content of Scenedesmus obliquus was different.On the 8th day of exposure experiment,when the concentration of?-Fe₂O₃ was 8 mg·L^-1,the content of chlorophyll a was 2.26 mg·L^-1,which was significantly higher than other experimental groups;when the concentration of?-Fe₂O₃ was 8 mg·L^-1 The chlorophyll a content was 2.32 mg·L^-1,which was higher than other experimental groups and the changes were similar.3)Under the exposure conditions of?-Fe₂O₃ and?-Fe₂O₃,the chlorophyll a of Anabaena was induced.The chlorophyll a content in the experimental group was significantly higher than that in the blank group.The effects on CAT activity,MDA content,SOD activity and free radical content of Anabaena were different.At the 8th day,the concentration of?-Fe₂O₃ was 1mg·L^-1 in the experimental group,the free radical content appeared the maximum value of 5.8283?g·mL^-1.4)The ecological risk assessment of?-Fe₂O₃ and?-Fe₂O₃ by IBR method shows that?-Fe₂O₃ and?-Fe₂O₃ had a low ecological risk.