The Toxicity Of Chiral Cyflumetofen And Its Degradation Products To Zebrafish Embryos

The toxicity of chiral compounds to non-target organisms has become a matter of concern in recent years.As a new chiral pesticide,the enantioselective toxicity of CYF enantiomers and its degradation products on aquatic organisms and the different toxicity of parent compounds and degradation products were unclear.However,chiral compounds usually present different activity and ecological toxicity which lead to the results were unsure.In this study,developmental toxicity and genotoxicity of cyflumetofen and its degradation products were evaluated from the point of enantiomer.The research provided an important theory for the rational use of cyflumetofen in China.The main contents and results of this study are as follows:1.The study finished the acute toxicity research of cyflumetofen enantiomers and its degradation products according to the OECD.After pesticides exposure to zebrafish embryos,the LC₅₀value of 96 h was calculated.According to the acute toxicity results,we found the order of pesticide was S-CYF>Rac-CYF>R-CYF,the toxic value of S-CYF was 290.04 mg/L which was lower more than R-CYF(669.70 mg/L)and Rac-CYF(655.07 mg/L)(p<0.05),and the toxic of S-CYF was 2.3 folds more than R-CYF.The toxicity of B-1 was 5.65 mg/L,B-3 was 260.54 mg/L,and the toxic of B-1 was52,115 folds more than B-3 and Rac-CYF.2.During the early development of zebrafish embryos,there were a series of deformities.The effects of the chemical compounds on yolk sac edema,pericardial edema,and abnormal spontaneous movement were investigated.There were significant differences between S-CYF and R-CYF(p<0.05)at 50 mg/L,and the effect of S-CYF was more toxic than R-CYF.Moreover,B-1 and B-3 exited a significant difference at 10 mg/L(p<0.05),B-1 was 4.2,5.1 folds more than B-3 and Rac-CYF.At 72hpf,S-CYF was more toxic than R-CYF;Cyflumetofen enantiomers had enantiioselective toxicity about curved body at 500 mg/L(p<0.05),and S-CYF was more toxic than R-CYF,B-1 and B-3 exited significant difference at 10 mg/L.3.In this study,we researched the enantioseclective bioconcentration of cyflumetofen and its degradation products in zebrafish through SFC-MS/MS.The results indicated that the perfect method was extracted by methanol.The results indicated that the recovery of cyflumetofen and its degradation products in zebrafish was 63.7%-116.7%,(spiked levels were 50?g/L,500?g/L,1000?g/L),and the relative standard deviation(RSD)was 1.1%-15.8%,standard working curve 50,100,200,500,1000?g/L,linear correlation coefficients are all better than 0.99,LOQ was range from 16.65?g/L-39.99?g/L.Moreover,according to the pesticide concentration of cyflumetofen and degradation products,S-CYF was enriched firstly in cyflumetofen enantiomers.In degradation products,the concentration of B-1 was higher,and it was 3.6 folds more than B-3.4.Genotoxic research of degradation products were investigated to study genotoxic mechanism.The results of comet assay and Western Blot indicated that there was genotoxicity of B-1 at 75 mg/L(p<0.05),and the toxic effect increased together with the concentration,B-1 was 3.3 folds more than B-3.Moreover,the results of expression level of Bax and Bcl-2 demonstrated that B-1 and B-3 had potential genotoxicity.The above results indicated that the developmental toxicity and genotoxicity of cyflumetofen enantiomers and degradation products had the similar results with acute toxicity,the order was S-CYF>Rac-CYF>R-CYF,B-1>B-3.This work provided an important theory of cyflumetofen using at garden through the toxicity research on zebrafish.