Endocrine Disrupting Effects Of Typical Bisphenols And Their Ecological Risks In The Sediments Of Taihu Lake

Bisphenol compounds have good optical properties and high temperature stability,so they are often used as the main raw materials and additives for the production of electronic components,optical instruments and other products.However,these bisphenols are difficult to biodegrade,leading to their widespread presence in environmental media as a class of contaminants.Compared with heavy metals and other pollutants,there are relatively few studies on the distribution of bisphenol pollutants in the environment.In addition,the toxic mechanism of other bisphenol compounds except BPA is still unclear.In view of this,this study selected zebrafish embryos as a model organism to study the endocrine effects of typical bisphenol compounds on aquatic organisms and the effects of metabolism-related genes;the pollution characteristics,effect mechanism and ecological risk of different types of bisphenol compounds（especially emerging bisphenol pollutants）were systematically studied.Taihu Lake sediments were selected as the research object to systematically investigate the content level and distribution characteristics of typical bisphenol compounds in surface sediments.The main results are as follows:1.Zebrafish was used as a model organism to reveal the endocrine disrupting and metabolic toxic effects of bisphenols.By consulting the literature and verifying the LC₅₀of three bisphenol compounds:BPA,BPAF and BPF,three concentration gradients of 10%LC₅₀,25%LC₅₀and 50%LC₅₀were set up for toxic exposure in turn.It was found that the development morphology of zebrafish embryos changed after exposure to the above three bisphenol compounds.Among them,the heartbeat of zebrafish embryos in BPA and BPAF exposure experiments at different concentrations changed correspondingly compared with that of the control group,and the heartbeat speed slowed down.Various concentrations of BPA and BPAF exposure solutions also affected the body length of zebrafish at 96 hpf in the exposure experiment,showing a certain degree of inhibition.The heart rate and body length of zebrafish embryos at 96hpf did not change significantly compared with the control group.In addition,in addition to changes in heart rate and body length,different degrees of epidermal darkening and pericardial edema were observed in 96 hpf zebrafish embryos exposed to different concentrations of BPA.2.The zebrafish embryos were exposed to different concentrations of BPA solution to 100 hpf,and the expression of endocrine-related genes in the body was changed to varying degrees compared with the control group.The expression of cyp19a1b gene was significantly up-regulated under the action of BPA;the expression of vtg1 gene was up-regulated by BPA in a concentration-dependent manner.After exposure to BPAF solution to 100 hpf,the expression of endocrine-related genes changed accordingly,and the expression of cyp19a1b gene changed most significantly.In addition,the expression level of ar also changed relatively large.After zebrafish embryos were exposed to BPF solution to 100 hpf,the expression of endocrine-related genes in vivo also changed,and the expression of cyp19a1b gene changed most significantly.In addition,the expression level of vtg1also changed relatively large.3.Zebrafish embryos were exposed to BPF solution to 96 hpf,the expression of metabolism-related genes changed,and the expression of cyp1a gene changed most significantly.In addition,the expression level of gss also changed relatively large.4.In this study,the pollution status of 13 bisphenol compounds in Taihu Lake sediments was analyzed,and a total of 6 compounds（BPA,BPS,BPZ,BPF,BPAF,BPAP）were quantitatively detected.The detection rates of target c ompounds were all above 60%,and the detection rates of BPA,BPAF and BP F were 100%.The descending order of average concentration was BPA（1.98±1.08）>BPF（1.13±0.54）>BPS（0.98±0.80）>BPAF（0.57±0.56）>BPZ（0.42±0.33）>BPAP（0.15±0.14）μg/kg.In addition,from the perspective of spatial distribution,BPA p ollution is the highest,and it is more polluted in the northwest and southeast l akes.BPS and BPZ were heavily polluted in the northwest lake area.BPAP p ollution is mainly concentrated in the southwest lake area.The pollution of BP AF in the southeastern region is more serious;BPF is heavily polluted in the northeastern lake area.5.Based on the existing toxicity data screening methods,the chronic toxicity data of BPA,BPAF,BPAP,BPF,BPS and BPZ were screened according to the principles of reliability,correlation and accuracy.And the BPA species sensitivity distribution curve was constructed.For the other five bisphenol compounds,the evaluation factor method was used to derive the predicted no effect concentration in the water.The PNEC values of BPA,BPF,BPS,BPAF,BPZ and BPAP in sediments were 33.741,0.120,0.002,1.688,6421.312 and 761.991μg/kg,respectively.6.The risk values of six bisphenol pollutants in surface sediments of Taihu Lake were calculated by risk entropy method.This study found that BPAP and BPZ had no ecological risk in surface sediments of Taihu Lake.The risk entropy of BPA in 88.2%of sediment samples was less than 0.01,which was basically risk-free.BPAF was at low risk in 29.4%of sediment samples,and BPAF risk entropy was between 0.01-0.1in 64.7%of sediment samples,which was at medium risk.The results show that BPF and BPS are at high risk in sediments from the Taihu Lake region.On the whole,the total risk value of sediments in Taihu Lake area is generally less than 1,showing moderate risk.