PFOS对斑马鱼胚胎及仔鱼的生态毒理效应

Abstract

Perfluorinated compounds( PFCs) are a family of fluorine-containing chemicals with unique properties to make materials stain,oil,and water resistant,and are widely used in diverse applications. As one of the most used anthropogenic PFCs,perfluorooctane sulfonate( PFOS) has been received much attention in recent years. It is a new kind of persistent organic pollutants( POPs),which have been found to be accumulated and biomagnified ubiquitously through food chain all over the world. PFOS poses serious risks to the health of many aquatic organisms and the safety of aquatic ecosystem. The potential toxicity of PFOS is of increasingly ecological concern. In the present study,the ecotoxicological effects of PFOS exposure on embryo and larva of zabrafish Danio rerio were examined to evaluate the possible hazard of this pollutant to development and behavior of fish and to pursue a potential biomarker of PFOS contamination. Embryos of zebrafish were exposed to 0,0. 1,1 and 10 mg / L PFOS in 4 hour-post-fertilization( hpf). Mortality,deformation rate,heart rate, locomotor performance and growth of zebrafish larvae,and hatching rate of zebrafish embryos were investigated. Proportion of motile individual,motion distance,pause frequency,average distance of each movement and maximum distance of continuous locomotion were used to quantify the locomotor performance of zebrafish larvae. PFOS exposure showed remarkable effects on hatching rate,mortality and deformation rate of zebrafish( P ﹤ 0. 05). Hatching delayed and cumulative hatching rate decreased significantly after the embryos were exposed to 10 mg / L PFOS( P ﹤ 0. 05). The cumulative mortality and deformation rate of zebrafish larvae at 6 day-post-fertilization( dpf) upon exposure to 10 mg / L PFOS increased significantly( P ﹤ 0.05). Heart rate of zebrafish larvae at 4 dpf and 8 dpf was significantly affected by PFOS exposure( P ﹤ 0.05) and increased with enhanced PFOS concentration. PFOS exposure imposed marked influence on locomotor performance of zebrafish larvae at 6 dpf and 9 dpf( P ﹤ 0.05). Maximum distance of continuous locomotion and proportion of motile zebrafish larvae at 6 dpf increased significantly after exposed to 10 mg / L PFOS( P ﹤ 0.05). PFOS affected the locomotor performance of zebrafish larvae at 9 dpf in a dose-dependent way. Motion distance,pause frequency, and average distance of each movement decreased with the increase of PFOS concentration,whereas maximum distance of continuous locomotion increased with enhanced concentration of PFOS. Additionally,significant decrease or a decreasing trend in growth( body length) and mouth width at 6 dpf and 9 dpf was observed in PFOS exposure groups. Mouth width: body length ratio and mouth width: head length ratio of zebrafish larvae were dramatically affected by PFOS exposure( P ﹤ 0.05). The overall results indicated that PFOS imposed clearly developmental and behavioral toxicity on zebrafish embryos and larva. The heart rate,locomotor performance,mouth width: body length ratio and mouth width: head length ratio of zebrafish larvae might be used as an integrative biomarker or indicator of aquatic environmental PFOS contamination.