Biotoxicological Effects And Risk Assessment Of Zebrafish By PFOS And PFOA

In order to have a better understanding of the toxicity effect of PFOA and PFOS to aquatic organisms,indoor exposure test was conducted in this study.The free radicals?ROS?,superoxide dismutase?SOD?,malondialdehyde?MDA?,acetylcholinesterase?AchE?,lactate dehydrogenase?LDH?were analyzed by the toxicity test of PFOS and PFOA on zebrafish to determine their toxic effects and analyze the reasons.Ecological risk assessment of single exposure and combined exposure was carried out using the Integrated Biomarker Index?IBR?method,and the results were compared with each other.The experimental results are as follows:1)PFOS was a material with middle toxicity,the results showed that PFOS can induce the oxidative stress reaction of zebrafish.PFOS can induce injury to zebrafish cell,break dynamic balance and produce ROS and MDA.The results was in good agreement with the ROS content and MDA content during experiment.The ROS and MDA increased as the concentration increases.There is a concentration-effect relationship between PFOS and the content of ROS and MDA.After exposure for 3 days,The SOD was increased as the concentration of PFOS increases.After exposure 6 days,the activity of SOD was decreased by PFOS.The activity of AchE on zebrafish head was increased during experiment.After 6 days,the activity of LDH was increased,after exposure for 9 days,the activity of LDH on zebrafish muscle tissue was decreased,and there is a concentration-effect relationship between PFOS and LDH.2)PFOA was a drug of low toxicity,the results showed that there is a time-effect relationship and concentration-effect relationship between PFOA and the zebrafish oxidative stress reaction.The change of SOD activity was opposed to the content change of ROS and MDA.PFOA has neurotoxicity,the amount of acetylcholine in synaptic space was reduced and excitation transmission was inhibited,because the activity of AchE in zebrafish was increased.The activity of AchE on zebrafish head was increased firstly and then decreased.The activity of LDH on zebrafish muscle tissue was decreased firstly and then increased,but was decreased finally.3)The oxidative damage of zebrafish caused by combined exposure of PFOS and PFOA was significantly higher than single effect and inspired earlier.The ROS and MDA content,AchE activity were induced by PFOS and PFOA combined exposure,and the results indicate that there is a concentration-effect relationship between biological index and exposure group.The activity of SOD on zebrafish muscle tissue was decreased firstly and then increased by PFOS and PFOA combined exposure after 9 days,but increased firstly and then decreased after exposure for 12 days.4)In the IBR analysis,the ecological impact of the 15+135mg·L^-1 exposed group on zebrafish was significantly higher than thus of the other combined exposure groups,PFOS single exposure groups and PFOA single exposure groups,which had the greatest ecological risk.