Study On Regional Distribution Characteristics Of Plastic Additive TBEP At The Mouth Of Nanyang Lake And Its Toxic Effects On Carp

Organophosphate plastic additives are new flame retardants.Compared with all flame retardants,the proportion of organophosphate plastic additives is increasing year by year.Studies have shown that organophosphates have a variety of toxicity to organisms,including neurotoxicity,reproductive toxicity,endocrine toxicity and so on.We investigated the pollution of plastic additives in the Nanyang Lake estuaries,and selected Tris(2-butoxyethyl)phosphate(TBEP),an organophosphate plastic additive,as an experimental poison to study the toxic effect of TBEP on carp(Cyprinus carpio):Dynamic changes of oxidative stress(SOD,MDA),inflammatory response(TNF-?,IL-1?protein and gene expression),apoptosis(caspase-3,caspase-9 and mitochondrial ultrastructure)in liver of carp.The purpose of study is to provide data support for the analysis and evaluation of freshwater ecotoxicity of TBEP.The results showed that:1.The experimental methods are Solid phase extraction(SPE)and Gas chromatography-mass spectrometry(GC-MS).The concentration of TBEP in the polluted water environment(such as the intake canal of the water company and sewage pipe of the city)was relatively high,ranging from 76.17?g/L to 3875.29?g/L,and more kinds of plastic additives were detected.In the river of the urban area,the TBEP concentration was 3.12?g/L,and the concentration at estuary of the lake was1.18?g/L.2.According to the experimental data of acute toxicity of TBEP to carp,the96h LC₅₀of TBEP to carp is 10.04 mg/L.According to the standard of acute toxicity classification of fish,TBEP is moderately toxic to carp.3.Oxidative stress:(1)SOD:Under TBEP stress,the activity of SOD in the liver of carp in the experimental group showed a phenomenon of"low promotion and high inhibition",and showed a dose-time effect.The results showed that under the condition of low concentration group(100?g/L),TBEP poison stimulated the phenomenon of oxidative stress and up-regulated the expression of SOD.Under the condition of high concentration group(250?g/L),it inhibited the expression of SOD and aggravated the oxidative damage of organism,and with the extension of time,the change of SOD activity was more significant.(2)MDA:With the increase of TBEP,the content of MDA in liver of carp increased significantly,and showing a dose-time effect.The results showed that high concentration of TBEP led to lipid peroxidation in the membrane.Inflammatory response:(1)Inflammatory protein:Under the stress of low concentration of TBEP(100?g/L),the contents of pro-inflammatory cytokines TNF-?and IL-1?in the liver of carp did not change significantly.But in the high concentration group(250?g/L),TNF-?and IL-1?increased significantly.The results showed that the inflammatory reaction was induced in the high concentration group(250?g/L),and the pro-inflammatory factors of TNF-?and IL-1?were released in large quantities,and the injury of the organism was aggravated.(2)Inflammatory gene:Under TBEP stress,there was no significant change in the gene expression of TNF-?and IL-1?in the low concentration group(100?g/L)compared with the control group,but the gene expression level of TNF-?and IL-1?in the high concentration group(250?g/L)increased significantly.The results showed that low concentration of TBEP could not induce organism to up-regulate the expression of pro-inflammatory factor gene.With the increase of concentration,high concentration of TBEP could induce the up-regulation of pro-inflammatory factor gene expression and cause inflammation.Apoptosis:(1)Apoptotic protein:Under the stress of TBEP(100?g/L),the content of caspase-3 and 9 in the low concentration group was not significantly higher than that in the control group,but the content of caspase-3 and 9 in the high concentration group increased significantly under the stress of TBEP(250?g/L).It is suggested that TBEP can induce apoptosis of carp liver cells.(2)Transmission electron microscope analysis:In the low concentration group(100?g/L),the shape and structure of mitochondria and intracellular organelles in the liver of carp were intact,and the number of organelles had no significant change.In the high concentration group(250?g/L),the mitochondria were swollen and the cristae structure was disordered and the number decreased.Apoptosis phenomena such as vacuolation and autophagy vesicles appeared in the cells.In summary,TBEP can cause oxidative stress in the liver of carp,release of inflammatory response factors,cause inflammation in the liver,change the structure of hepatocyte mitochondria,cause the expression of apoptotic proteins,and eventually lead to apoptosis.