Toxic Effects And Metabolic Effects Of Agricultural Organosilicon Spray Adjuvants On Zebrafis

Agricultural silicone spray auxiliaries are usually mixed with pesticides,herbicides,fungicides,plant growth regulators and other pesticides in agriculture,so as to improve the active efficacy of pesticides,because of their excellent properties such as good wetability,expansibility,permeability and so on.In recent years,more and more studies have found that some organosilicon spray additives have potential negative effects on environmental organisms.However,the toxic effects of organosilicon additives on environmental organisms and their enrichment,digestion metabolism in environmental organisms are quite scarce.Therefore,in this paper,zebrafish were taken as experimental animals to study the acute toxicity,bioenrichment and metabolomics effects of agricultural silicone spray additives on zebrafish,so as to provide reference for the safety risks of pesticide additives on aquatic organisms.The contents of the study include the following:1.Identify 8 kinds of agricultural silicone spray additives commonly used in the domestic market.The main active ingredient of 4 products is polyether modified trimethylsiloxane（TSS-H）,and further separate TSS-H using high-performance liquid chromatography to produce pure products.After ultra-high performance liquid chromatography tandem high resolution mass spectrometry（UHPLC-HRMS）technology test,the purity of 98.6%,this pure product can be used as the quantitative analysis standard in this study.Combined with high performance liquid chromatography/evaporable light scattering detector（HPLC-ELSD）technology,the content of each oligomer in TSS-H in pure products was determined.It was found that the main content of TSS-H in 6-10EO group was 12.72%、14.64%、14.81%、13.17%、10.65%,respectively.2.Combined with Eclipase Plus C₁₈（2.1×50 mm）column and UHPLC-HRMS technology,a method for the pretreatment,detection and analysis of TSS-H in zebrafish and water was established.The results show that:The average recoveries of TSS-H with 4-12 EO groups in zebrafish matrix were 89.15%-104.50%,RSDS were2.10-6.04,and the correlation coefficient（R²）was>0.99 when the total concentration of TSS-H was 0.04,0.4 and 4 mg/kg.The average recoveries of TSS-H oligomers in aquaculture zebrafish aqueous substrates ranged from 78.12%to 95.82%,and RSDS ranged from 2.36 to 9.81.The accuracy and precision of the method are qualified.3.The acute toxicity and bioenrichment-degradation experiments of TSS-H on zebrafish were carried out.The results showed that the LC₅₀of TSS-H to zebrafish was 6.71±0.04 mg/L in 96 h,and the toxicity level was toxic.In the process of biological enrichment of TSS-H in zebrafish,the concentration of TSS-H oligomers of 4-12EO group reached the maximum in zebrafish after 21 d at two dosages of0.0671μg/m L and 0.671μg/m L.The concentrations of TSS-H oligomers in Zebrafish were 0.008-0.044μg/mg and 0.018-0.343μg/mg,respectively.4.The BCF values of TSS-H of 4-12 EO in low concentration group（0.0671μg/m L）ranged from 1.87-9.86 at 21 d,while those in high concentration group（0.671μg/m L）ranged from 0.57-7.64,respectively.In the elimination experiment of TSS-H on zebrafish,the TSS-H half-life of 4-12EO group in low-dose treatment group（0.0671μg/m L）was less than 1.48 d,and the TSS-H half-life of 4-12EO group in high-dose treatment group（0.0671μg/m L）was less than 2.37 d.5.Nontarget metabolomics study of TSS-H on Zebrafish.The results show that:There were 141 different metabolites in the 0.671μg/m LTSS-H zebrafish treatment group compared with the blank control group,with 92 significantly up-regulated and49 significantly down-regulated,and 139 different metabolites in the 0.067μg/m L TSS-H zebrafish treatment group compared with the blank control group.There were110 significantly up-regulated metabolites and 29 significantly down-regulated metabolites.These differential metabolites mainly included organic acids and derivatives,lipids and lipid molecules in the classification of HMDB compounds.Annotation of differential metabolites into the KEGG metabolic pathway showed that the TSS-H treatment group at low concentration mainly affected the lipid metabolic pathway in zebrafish,such as the metabolism of arachidonic acid,steroid hormones and linoleic acid.High concentration of TSS-H treatment group mainly affected amino acid metabolic pathways,such as valine,leucine and isoleucine biosynthesis,phenylalanine,tyrosine and tryptophan biosynthesis,tryptophan and other metabolic pathways.Most of these metabolic pathways are related to abnormal energy metabolism,oxidative stress and changes in biofilm composition.