Toxicity Of Nano Fe₂O₃ To Synechococcus Sp.PCC7942 And The Alleviating Effect By Fulvic Acid

With the unique properties of nanomaterials,nanoparticles are received increasing application.Inevitably,they will be released to environment and cause potential toxicity to organism.Recently,more and more researches focus on the toxicity of nanomaterials to algae,however,most of them reported eucaryon and neglect the impact of natural organic matter(NOM)in complex natural water.This research was therefore aimed to study the toxicity of procaryotic organism,synechococcus.Systematically investigated the 48h acute toxicity and chronic toxicity of nFe2O3 to synechococcus and analyzed the influence of Fulvic acid(FA)on the nanotoxicity to algae and their physicochemical property in the environment.1)The 48h acute experiment shows that nFe2O3 has toxicity on synechococcus and dosage respectively.Low concentration of nFe2O3 in our test could not induce nanotoxicity,however,when the concentration above 10 mg·L-1,the content of chlorophyll a,total soluble protein and sugar show significant reduction.2)High concentration of nFe2O3 could cause significantly oxidative damage.The activity of CAT at 30 mg·L-1 of nFe2O3 was 4.44 times higher than the control group and approximately 3.31 times and 3.34 times greater than that in the untreated group.Nanoparticles can induce algae to generate excessive ROS and antioxidant enzymes are the fist line of defense system.3)Addition of FA can mitigate nanotoxicity to synechococcus.With the presence of 10,20 and 40 mg·L-1 with 10 mg·L-1 nFe2O3,the content of chlorophyll a,total soluble protein and sugar,along with activity of antioxidant enzyme recover to control level.4)The comparison between acute toxicity and chronic toxicity to synechococcus show that nFe2O3 particles have no nanotoxicity in the long term effect.