Study On Residues Of Pesticides And Polybrominated Diphenyl Ethers In Pond Aquaculture Products And Prediction Based On Solid Phase Microextraction

The study focused on five common aquatic products of daily life in 21 aquaculture ponds in the Yangtze River Delta region as research objects.The pretreatment and determination methods of organophosphorus pesticides and polybrominated diphenyl ethers in organisms,sediments,and water bodies were established.The organophosphorus,organochlorine,pyrethroid pesticides and polybrominated diphenyl ethers were identified as hydrophobic organic contaminants.The levels of residual contaminants and food health risks in aquatic products and culture environments were evaluated,The free-dissolved concentration(C_free)of pore water in aquaculture sediments was determined using solid-phase microextraction which using PDMS as the material.The bioavailability of pollutants in sediments was evaluated.A preliminary analysis of the sources of contaminants in the culture environment was conducted,and a prediction model based on solid-phase microextraction was established to predict the accumulation of contaminants in the aquaculture product.The results of the study are as follows:methods for the detection of two pollutants,organophosphorus pesticides and polybrominated diphenyl ethers,in organisms and sediments,?1?Methods for the detection of two organophosphorus pesticides and polybrominated diphenyl ethers in organisms and sediments were established,as well as the pretreatment methods for organophosphorus pesticides?OPPs?,organochlorine pesticides?OCPs?,pyrethroid pesticides?PEs?and polybrominated diphenyl ethers?PBDEs?in water samples.Pretreatment of OPPs in biological samples:Microwave extraction for extraction,the extraction solvent was 15mL dichloromethane,the extraction temperature was 80°C,the extraction time was 10min,the power was 1600W,and the degreasing was followed by purification,ENVI-CarbTM/LC-NH2 was used as the purification column,the column was eluted with 13 mL dichloromethane and 1 mL of acetone and 1 mL of dichloromethane.Pretreatment method of OPPs in sediment samples:no degreasing,purification column is self-purification column and the rest are the same as biological pretreatment methods.Pretreatment methods for OPPs,OCPs,and PEs in water samples:before the extraction,1L of water samples were filtered through a 0.45?m glass fiber filter to remove large particles,waters Oasis HLB solid phase extraction cartridge was activated with 10 ml of ethyl acetate,methanol and water in sequence,and then the target on the HLB column was eluted with 10 ml of ethyl acetate.Determination of OPPs:Detection of 9 kinds of OPPs in organisms,sediments,and water samples using gas chromatography mass spectrometry.Pretreatment methods for PBDEs in biological and sediment samples:Extraction by microwave extraction,extraction solvent 15 mL acetone/hexane?V/V,1:1?mixture,extraction temperature110°C,extraction time 30 min,power At 1600 W,the step of degreasing the organisms was one more step,Silica gel and alumina were used as the purifying column packing,and 20 mL of n-hexane/dichloromethane?V/V,1:1?was used to elute the purification column.Pretreatment method of PBDEs in water sample:efore the extraction,1L of water samples were filtered through a 0.45?m glass fiber filter to remove large particles,Waters Oasis HLB solid phase extraction cartridges were sequentially activated with 10ml of n-hexane,methylene chloride,methanol,and water before extraction,and then sequentially eluted with 3 ml of methanol,6 ml of dichloromethane and 6 ml of n-hexane elution HLB cartridges.Methods for the determination of PBDEs:Detection of 10 kinds of PBDEs in organisms,sediments and water samples by gas chromatography mass spectrometry.At the spiked concentrations of 5,50,50 ng·g^-11 and5,150,50 ng·L^-1,the recoveries of OPPs and PBDEs in organisms and sediments,the three pesticides and PBDEs in water samples were all Above 70%,the relative standard deviations are all below 15%,which is in accordance with the detection requirements of pesticides and polybrominated diphenyl ethers.he detection limit of OPPs were 1.0-2.0ng·g^-1?dw?in organisms,0.16-0.33 ng·g^-1?dw?in sediment,0.50-1.0 ng·L^-1 in water.,The detection limit organisms of OCPs and PEs in water bodies were the same as that of OPPs.he detection limit of PBDEs was 1.0-2.0 ng·g^-1?dw?,the sediment was0.16-0.33 ng·g^-1?dw?,and the water body was 0.09-0.89 ng·L^-1,can be used for the detection of pesticides and polybrominated diphenyl ethers in actual organisms,sediments,and water samples.?2?Based on the study of residual levels of OPPs,OCPs,SPs,and PBDEs in pond cultured aquatic products and environment in the Yangtze River Delta region,it was found that?OPPs residues were undetected to 391 ng·g^-1?dw?,and that OCPs residues were 16¹82 ng·g^-1?dw?,the residual PEs were 20⁵86 ng·g^-1?dw?,and the residual PBDEs were 36³69 ng·g^-1.Compared with others'studies,the residue level is not high,among which triazophos,phoxaphos,quizphos,chlorpyrifos,lambda-cyhalothrin,and pentathion?BDE-85,99,100?with higher hydrophobic and lipophilic properties,Hexabromodiphenyl ether,are easier to accumulate in the aquatic product body,the main pollutants of OCPs are HCHs,which mainly from historical residues,breeding pond environment in the PBDE and pesticide pollution slightly heavier.The total HI values of pesticide contaminants and polybrominated diphenyl ethers in aquatic products of 21 culture ponds ranged from 0.012 to 0.053,which was far less than 1,This means that it is safe to eat aquatic products from ponds in the Yangtze River Delta region for the harm to human health of OPPs,OCPs,SPs and PBDEs.?3?By analyzing the Cfree of two types of hydrophobic organic pollution in aquaculture sediments measured by solid-phase microextraction,it was found that K_oww will affect the free dissolved state concentration of pollutants in the pore water of the sediment,that is,the stronger the hydrophobic lipophilicity,the lower the bioavailability of pollutants in the pore water of sediments,by comparing the free dissolved state concentration of the pore water in the sediment with the free dissolved state concentration of the overlying waterit is concluded that the proportion of pollutant monomers is greater than 1,The concentration of free dissolved contaminants in sediment pore water is higher than that of overlying water,this indicating that sediment can be considered as an internal source of pesticide pollutants,the tendency of pollutants in pond culture environment is from bottom sediment to overlying water and the smaller the K_ow,the more obvious the trend is,which provide scientific and convenient evidence for the evaluation of bioavailability of pollutants in sediments.Calculate the BCF of the four pollutants,it at a normal level and increase with the increase of K_ow,he four-pollution pollutant-accumulation factor?BSAF?is less than 1.2,which proves that the degree of accumulation in the body of aquatic products is not great.?4?A PDMS quantitative calculation model for pesticide pollutants and polybrominated diphenyl ethers was established based on solid phase micro-extraction technology.The model has been used to calculate the predicted value of pollutant accumulation in aquatic products.Compared with the measured value,the difference is not more than one order of magnitude,which proves that the model based on solid-phase microextraction can be used to predict the bioaccumulation of organic pollutants in sediments.?5?The types and detection rates of pollutants detected in aquatic products were more consistent with those in sediments and water bodies than in sediments.By studying the balance of pesticide pollutants and polybrominated diphenyl ether monomers in sediments and water in aquatic products,we found that the balance between the two types of pollutants and sediment pore water is higher than that of overlying water,it is further proved that sediment is an important source of pesticide pollutants and polybrominated diphenyl ethers in aquatic ponds and aquatic products.In summary,pesticide residues and polybrominated diphenyl ether?PBDE?residues in pond cultured aquatic products in the Yangtze River Delta region are not high and have no food health risks,Solid-phase microextraction which using PDMS as material can be used to evaluate and predict pesticides and PBDE pollution in culture areas.However,sediments are the most important sink of various organic pollutants,the re-release of pollutants from sediments may be an important cause of pesticide and PBDE pollution in aquatic products.Therefore,in addition to focusing on aquaculture water standards,the standards for the production of hydrophobic organic pollutants?HOCs?in aquaculture sediments are also urgently set up,and the supervision of HOCs should be strengthened,which is of great significance for improving and improving the quality of aquatic products.This study not only evaluated the food health risks and the residues of pesticide and PBDE in pond aquaculture aquatic products of the Yangtze River Delta region,but also provided a scientific basis for the evaluation of aquatic product quality and safeguarded the dietary health of local residents,it can also simplify the process of aquaculture environmental pollution assessment.At the same time,it provides a theoretical basis for predicting the pollution status of organic pollutants in the culture area based on solid-phase microextraction and the optimization of breeding environment quality.