Investigation on Hormetic effects and corresponding mechanisms of typical organophosphorus flame retardants on Cyanobacteria
To explore the toxic effects of Organophosphate Flame Retardants(OPFRs)on cyanobacteria,this study set Microcystin aeruginosa as the experimental model of Cyanobacteria to determine the influence of typical OPFRs alkyl OPFRs-Triethyl Phosphate(TEP)and chlorinated OPFRs-Tris(2-Chloroethyl)Phosphate(TCEP)on the algae growth,Chlorophyll a(Chi a),Carotenoids(Car),Reactive Oxygen Species(ROS),Superoxide Dismutase(SOD),Catalase(CAT),Malondialdehyde(MDA),and hydrophobicity.The results show that both TEP and TCEP induce the hormetic phenomena on the growth of Microcystis aeruginosa,i.e.,TEP and TCEP stimulate the growth at low doses but inhibited it at high doses.The stimulatory concentration range for TEP and TCEP are respectively 6.80 × 10-4-1.53 × 10-1 mg/L and 5.87 × 10-5-1.54 × 10-mg/L,while the maximum stimulatory rate for TEP and TCEP is 8.08％and 13.73％,respectively.Furthermore,TEP's and TCEP's inhibitory concentration ranges are respectively 1.53 × 10-1-288 mg/L and 1.54 × 10-1-293 mg/L,and the corresponding maximum inhibitory rate are 16.96％and 34.21％,respectively.The variations of relevant physiological indicators induced by TEP and TECP indicate that low-dose OPFRs can promote the photosynthetic activity to provide more energy for algal cells and moderately increase the intercellular ROS amount to positively regulate the cellular life activities,thus stimulating the algal growth.On the contrary,high-dose OPFRs can hinder the synthesis of photosynthetic pigments to reduce the energy supply,induce excessive ROS production to cause oxidative damage on algae cells,and damage the cell membrane via changing the hydrophobicity,ultimately inhibiting the growth of Cyanobacteria.These findings indicate that OPFRs can trigger the hormetic effects on Cyanobacteria growth,and the chlorinated OPFRs possess more obvious biological effects than alkyl OPFRs,hence OPFRs have the potential environmental risk to facilitate the formation of Cyanobacteria blooms within certain exposure concentration ranges.This study can provide reference data and a theoretical basis for the aquatic toxicity evaluation and corresponding environmental risk assessment of OPFRs.
basic disciplines of environmental science and technologyorganophosphorus flame retardantsMicrocystis aeruginosaHormesisphotosynthesisoxidative stress
万方数据
维普
