Study On Environmental Pollution Of Hexabromobiphenyls In Shanghai Area And Its Toxic Effects On Zebrafish

Hexabromobiphenyls(HexaBBs)have been approved as ones of the newly persistent organic pollutants in the Stockholm Convention since 2009,which can be exposed to soil and aquatic environment through a verity of ways,including wet deposition,runoff,and leaching.Soil and water substance sediments are theirs main reservoirs,soil organisms and aquatic organisms may become HexaBBs carriers by ingesting organic debris,river bottom sediments or directly ingesting HexaBBs.HexaBBs can produce biological amplification effect through the food chain,due to the persistent residue and lipophilicity of their.HexaBBs ingested by aquatic organisms may interfere with the body's endocrine system,and ultimately threaten the quality and safety of aquatic products,and even human health.HexaBBs are the most frequently detected polybrominated biphenyls(PBBs)components in environmental samples,biological samples and human tissues.In 2014,HexaBBs were added to Chinese Stockholm Amendment on Persistent Organic Pollutants,but the time of attention is relatively late,the standard method for the determination of PBBs in the environment and biological matrices have not been promulgated,and there are few studies on the pollution status,migration rules,and toxicological effects of HexaBBs in environmental media.An analytical method was established for determination of trace levels of HexaBBs in aquatic products by GC in this paper,and the accumulation characteristics of HexaBBs in different aquatic products were analyzed.According to the distribution of industrial areas in various jurisdictions in Shanghai,the nearby areas such as the production of flame retardant factories,electronics factories,and plastic factories were investigated,and 80environmental medias(water,soil and biological samples)were collected.The residual levels,distribution characteristics and potential sources of HexaBBs nearby some industrial areas in Shanghai were preliminarily discussed.PBB153 was selected as the exposure,and zebrafish was used as the model organism to preliminarily evaluate the effects of PBB153 on the levels of sex hormones(17?-estradiol(E2),testosterone(T))and vitellogenin(Vtg)in zebrafish.The main findings are as follows:(1)A gas chromatographic analysis method for 5 HexaBBs in aquatic products has been established.Several parameters were optimized in this study,including extracting reagents,ultrasonic time,types of solid-phase extraction column and capillary column.As a result,a satisfied effect was achieved when the sample was extracted by ultrasonic treatment for 10 minutes in 10 mL ethyl acetate,purified on silica gel SPE cartridges with impurity removal mode,collected the liquid(effluent and washing liquid)and blow to dryness by N₂,finally reconstituted with 1 mL of n-hexane,and detected successfully by gas chromatography with DB-17MS column.It was confirmed that the correlation of the5 HexaBBs measured by this method was good in the range of 0.20–10.00 ng·mL^-1,and the correlation coefficients R² were greater than 0.998.The recoveries ranged from 77.15%to 118.14%,with relative standard deviations(RSDs)in the range of 0.56%–13.32%at spiked levels of 1.00?g·kg^-1 and 5.00?g·kg^-1,and this method was used for the determination of 5 HexaBBs in actual samples such as Carassius auratus,Larimichthys crocea,and Eriocheir sinensis.The results showed that the method can be used for the quantitative analysis of HexaBBs residues in aquatic products,and the accumulation characteristics of HexaBBs in aquatic products originated from different.(2)The pollution status,potential sources and migration characteristics of HexaBBs in environmental media near some industrial areas in Shanghai were studied.The concentrations of HexaBBs were quantitatively analyzed in 80 environmental medias(water,soil and biological sample)with gas chromatography-mass spectrometer in this paper.The results showed that the detection rates of HexaBBs in water samples(n=13),soil samples(n=18)and biological samples(n=49)were 0%,66.67%,and 83.67%,respectively.The detection rates of PBB155,PBB153 and PBB154 in soil samples were44.44%,27.78%and 5.55%,respectively.The detection rates of PBB155,PBB153,PBB154,PBB156,and PBB159 in biological samples were 61.22%,44.90%,20.41%,8.16%,and 2.04%,respectively.HexaBBs were not detected in water samples,the detected content values of PBB155,PBB153 and PBB154 in soil samples were 0.108—0.173?g·kg^-1,0.111—0.159?g·kg^-1 and 0.138?g·kg^-1,respectively.The detected content values of PBB155,PBB154,PBB153,PBB156 and PBB159 in biological samples were0.103—0.237?g·kg^-1,0.101—0.238?g·kg^-1,0.103—0.257?g·kg^-1,0.102—0.169?g·kg^-1 and 0.178?g·kg^-1,respectively.In this study,HexaBBs were detected in environmental medias collected from nearby some industrial areas in Shanghai for the first time,although the conclusions showed that the residual level was low,it is possible to accumulate in organisms with high fat content,due to the persistent residue and lipophilicity of HexaBBs,people near the collection point may have a potential tendency to be exposed.This study provided basic data for monitoring the residual levels of HexaBBs in environmental medias and assessing the potential hazards of HexaBBs to organisms.(3)The effects of PBB153 on the levels of sex hormones(E2,T)and Vtg in zebrafish were preliminarily discussed.The results showed that PBB153 can inhibit the secretion of E2,T and Vtg in zebrafish to varying degrees,compared with the blank control group.The inhibitory effect was significantly enhanced(P<0.05),and there was a certain dose-effect relationship,with the increase of PBB153 exposure level.This may be because PBB153 interfered with the activity of rate-limiting enzymes(such as CYP19,CYP11A1)during the synthesis of E2 and T,and E2 is the main steroid hormone for the synthesis of Vtg,which in turn caused the decrease of Vtg levels;or after PBB153interacted with AhR,it induced the production of cytochrome P4501A1 or P4501B1,accelerating the oxidative metabolism of E2,and finally exhibited an anti-estrogen effect.In this study,zebrafish was used as the model organism to preliminarily evaluate the effects of PBB153 on the levels of E2,T and Vtg in zebrafish,providing a reference for studying the toxicological effects of PBBs and environmental pollutants on the endocrine system(hypothalamic-pituitary axis)of aquatic organisms.The study established a method for the determination of HexaBBs in aquatic products,the samples collected in Shanghai were determined and analyzed by this method,and obtained the latest level of HexaBBs pollution in environmental media near some industrial areas in Shanghai,which can provide corresponding data and technical support for issue and potential risks assessment of HexaBBs determination standards in the medium.In this study,zebrafish was used as the model organism to preliminarily analyze the effects of PBB153 on the levels of E2,T and Vtg in zebrafish.This is of great significance for revealing the regulation mechanism of PBBs and other environmental pollutants that interfere with the endocrine system of aquatic organisms.