Research On The Aquatic Ecological Risk And Sensitive Toxicity Mechanism Of Tris(2-Chloroethyl) Phosphate

Organophosphate esters（OPEs）are the main components of organophosphorus flame retardants,which are widely used in industrial and household products to increase the heat resistance and plasticity of products.The wide production and use of OPEs results in high concentrations and potential environmental risks.At present,the research on the toxic effects and mechanisms of OPEs is relatively weak,and it is difficult to provide theoretical support for the risk management and control of OPEs.Based on this,this paper carried out the sensitivity toxicity screening of OPEs and the reproductive toxicity effect and mechanism of typical OPEs on zebrafish under low-dose long-term exposure.The main research results are as follows:（1）The environmental concentrations of 15 types of OPEs in the Beiyun and Yongding Rivers in Beijing were detected,with OPEs concentrations ranging from365.83 to 450.16 ng·L^-1 in the North Canal and 14.86 to 156.94 ng·L^-1 in the Yongding River;The residues in wastewater from sewage treatment plants and traffic pollution sources are the main sources of OPEs in rivers;The ecological risk assessment results show that the risk of OPEs to aquatic organisms in the Beiyun and Yongding River can be ignored.We collected data on the concentration and toxicity of OPEs in typical surface water samples from around the world over the past decade and evaluated the potential risk of OPEs to aquatic species using the joint probability curve method.The results showed that Tris（2-chloroethyl）phosphate（TCEP）had the highest potential risk to aquatic organisms,with 5%,10%,15%,and 20%of species affected by TCEP in surface water,The global proportion of surface water that causes its risk is 99.82%,68.98%,13.05%,and 0.77%.（2）Collect and screen environmental surface water data and toxicity data of TCEP to aquatic organisms,classify their toxicity data into lethal toxicity,developmental toxicity,neurotoxicity,and reproductive toxicity,and use risk assessment methods to identify the most sensitive toxicity effects of aquatic organisms to TCEP.The results show that the sensitivity ranking of aquatic organisms to TCEP toxicity is as follows:reproductive toxicity>neurotoxicity>developmental toxicity>lethal toxicity.TCEP has the strongest reproductive toxicity to aquatic organisms.When the proportion of species affected by reproductive toxicity is 15,20,and 25%,the surface water ratio causing its reproductive toxicity is 92.26%,38.97%,and 4.01%,respectively.（3）With zebrafish as the model organism,the reproductive toxicity experiment was carried out under long-term low-dose TCEP exposure conditions.The results showed that TCEP had an estrogen effect and could inhibit the normal growth of zebrafish.In the high-concentration exposure group,there were reproductive toxicity effects such as female-male ratio imbalance,abnormal secretion of sex hormones,female zebrafish ovary development degradation,male zebrafish testis area reduction,etc.The molecular docking results showed that TCEP has a specific binding site（CTS A:530）with sex hormone binding globulin（ASN:A:82）and estrogen receptor,which can interfere with the normal synthesis and secretion of sex hormones,thereby affecting the normal reproductive function of zebrafish.