Study On The Toxicity Of PFOS And PFOA To Zebrafish Embryos

Perfluorinated Compounds (PFCs) are widely used in industry and civil products because of their excellent thermal stability, chemical stability, high surface activity and hydrophobic-oleophobic property. Widely application leads to the reality that PFCs exist in various environmental media, organisms and the human body. As the persistence, bioaccumulation and a variety of potential toxicity of typical PFCs, they have become research focus in the field of environmental science and toxicology. Studies on aquatic toxicity of PFCs could provide scientific basis for its ecological risk assessment.According to OECD Guidelines, the acute toxicity of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) on zebrafish embryos was investigated. With increase of the concentration of PFOS and PFOA, the scores of embryonic morphogenesis and hatching rate decreased, embryos mortality increased and the heart rate slowed down. The concentration-response relationships for the single toxicity of PFOA and PFOS were fitted by10commonly function models. The best-fit models for PFOA and PFOS were the Generalized-Logit-I function model and Aranda-Ordaz function model, respectively. With the best-fit models, the72h and96h LC50values for PFOA were obtained to be624.51mg/L and386.51mg/L, respectively, and the72h and96h LC50values for PFOS were obtained to be53.22mg/L and52.86mg/L.Based on the single toxicity, the joint toxicity of PFOS and PFOA was studied with CpFOS: CpFOA (mg/L:mg/L) as1:10,1:6,1:3and1:1. The results showed that the concentration-response relationships could be described by the Generalized-Logit-I model for mixtures with CpFOS:CpFOA of1:10,1:6and1:1. For mixture with CpFOS:CpFOA of1:3, the Aranda-Ordaz model was used. The joint toxicity of PFOS and PFOA was assessed by three methods. Results revealed that PFOS and PFOA showed additive effect at72h and mainly partial additive effects at96h for mixture with CpFOS:CpFOA of1:10; synergic effects for mixture with CpFOS:CpDOA of1:6and1:1; and antagonistic effects for mixture with CpFOS:CpFOA of1:1.The joint toxicity was also predicted by independent action (IA) and concentration addition (CA) models. The results showed that PFOS and PFOA had similar modes of actions at72h of exposure and have different modes of actions after96h of exposure for mixture with CpFOS:CpFOA of1:10. When CpFOS:CpFOA equaled to1:6, PFOA and PFOS had similar modes of actions. However, PFOS and PFOA had complex interactions for mixtures with CpFOS:CpFOA of1:3and1:1, and the joint t.oxicity could not be effectively predicted by CA or IA models...