| Per-and polyfluoroalkyl substances?PFASs?refer to a class of highly fluorinated aliphatics.PFASs are threatening to aquatic environment as they are persistent and bio-accumulative.The electroplating factories are important source of PFASs in aquatic environment.To figure out PFASs emission characteristic of electroplating factories and risk in surrounding aquatic environment is significant.PFASs concentration was got from field sampling analysis and paper searching.PNEC values of target PFASs were calculated by quantitative structure activity relationship?QSAR?model,interspecies relationship prediction?ICE?model,and species sensitivity distribution?SSD?model.The environmental risk was evaluated by risk quotients.1)Different kinds of PFASs were detected in the wastewater of electroplating factories and surrounding aquatic environment.The analysis method of 19 PFASs in water samples was established.The limit of detection was between 0.1 and 2.0 ng/L,and the recovery rates were between 81% and 122%.Concentrations of PFASs in wastewater of electroplating factories in Shenzhen were analyzed.Perfluorooctane sulfonate?PFOS,16.9 ng/L?and perfluorobutane sulfonate?PFBS,132 ng/L?were the main PFASs in wastewater and surrounding aquatic environment.Concentrations of 11 PFASs in aquatic environment surrounding other electroplating factories were obtained through literature searching.Perfluorobutane carboxylic acid?PFBA?,perfluorooctanoic acid?PFOA?,PFBS,perfluorohexane sulfonic acid?PFHx S?,PFOS and 6:2 Cl-perfluoroalkyl ether sulfonate acid?6:2 Cl-PFESA?were chosen as target PFASs in the wastewater and surrounding aquatic environment to evaluate the environmental risk based on field sampling analysis and literature searching.2)Acute toxicity data of PFASs to Pseudokirchneriella subcapitata,Chlorella vulgaris,Danio rerio and Daphnia magna were supplemented by QSAR models.QSAR models?R2>0.370?to predict acute toxicity of PFASs to the mentioned species were established based on the molecular descriptor calculated using MOPAC 2016 and EPI Suit.The models were evaluated using non-cross-validation and leave-oneout cross-validation.All models showed high predictive ability and certain statistical significance.It was found that the acute toxicity of PFASs was related to the lipophilicity,polarization and electron acceptor properties.3)The ICE models were used to construct the interspecies toxicity relationship between the substitute species and the predicted species,which further supplemented acute toxicity data of local species.We used ICE models to supplement the acute toxicity data of PFBA?13 pieces?,PFOA?34 pieces?,PFBS?17 pieces?,PFHx S?13 pieces?,PFOS?14 pieces?,6:2 Cl-PFESA?13 pieces?.4)The PNEC values were calculated through the SSD model.QSAR-ICE-SSD method was established based on QSAR models,ICE models and experimental toxicity data.The concentration values affecting 5% species in the ecosystem?HC5?were obtained using the fitted normal distribution curve.HC5 is divided by evaluation factor 5 to obtain PNEC values,namely 804 ?g/L?PFBA?,6.27×103 ?g/L?PFOA?,1.01×104 ?g/L?PFBS?,1.29×104 ?g/L?PFHx S?,2.09×103 ?g/L?PFOS?,254 ?g/L?6:2 Cl-PFESA?.Based on the PFOA and PFOS toxicity data from published papers,local species SSD models were constructed to estimate PNEC values.The results showed that it was 1.16 times?PFOA?and 1.20 times?PFOS?more than PNEC values from QSAR-ICE-SSD method.It indicted that the QSAR-ICE-SSD method established in this study was reliable to calculate toxicity effect and could be used for PNEC calculation of PFASs.6)The environmental risk of the six PFASs in factory's discharge and surrounding aquatic environment was evaluated based on the ratio of exposure concentration and PNEC values.The environmental risk of target PFASs in the factory's discharge and surrounding aquatic environment was low(0?1.21×10-4)and the highest risk quotient value(1.21×10-4)was from PFOS exposure. |
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