Developmental Toxicity Of Merey Crude Oil And Dispersant On Zebrafish Embryos

As shipping industry develops rapidly,oil spill accidents happen more and more frequently,which has caused great impact on aquatic environment.The oil spill dispersant,which can accelerate the diffusion of oil-slick,has been considered to be a common mean to handle oil spills.However,the use of oil dispersants could cause the secondary pollution to aquatic organisms and was still controversial.In this paper,the developmental toxicity of water-accommodated fractions(WAF),chemically enhanced WAF(CEWAF)of Merey crude oil and GM-2 dispersant to zebrafish(Danio rerio)embryos at 0-120 hour post-fertilization(hpf)is investigated.Mortality,hatching success,malformed effects,general morphology score(GMS)system and heart rate of zebrafish embryo-larva were observed.(1)Exposure to different dilution rates of WAF and CEWAF resulted in increased mortality and decreased hatching rare on zebrafish embryo-larva.WAF and CEWAF all induced a significantly concentration-dependent increase on mortality rate and a significantly concentration-dependent decrease on hatching rate.The mortality and hatching rates of zebrafish embryo-larva after exposed to CEWAF at different dilution rates were all higher than that of WAF at corresponding dilution rates.(2)Exposure to different dilution rates of WAF and CEWAF caused siginificantly concentration-dependent increase in teratogenic effects and decerase in heart rate on zebrafish embryo-larva,respectively.The malformantion ratios of pericardial edema and yolk sac edema of zebrafish embryo-larva after exposed to CEWAF at different dilution rates were all higher than that of WAF at corresponding dilution rates.The malformantion ratios of dorsal malformation and malformation of the tail of zebrafish embryo-larva after exposed to CEWAF at different dilution rates were all lower than that of WAF at corresponding dilution rates.The heart rate of zebrafish embryo-larva after exposed to WAF at different dilution rates were all higher than that of CEWAF at corresponding dilution rates.The GM-2 dispersant solution has a certain inhibitory for heart rate,but its effect was lower than that of CEWAF.(3)Exposure to WAF and CEWAF resulted in a siginificantly concentration-dependent decerase in GMS values on zebrafish embryo-larva.Indicating that WAF and CEWAF both induced a siginificant developmental retardation to zebrafish embryo-larva.The degrees of developmental retardation of zebrafish embryo-larva exposed to CEWAF with different dilution rates were serverer than those of WAF at corresponding dilution rates.Lower GMS values after exposed to WAF and CEWAF were mainly related with lack of spontaneous movement?resorbed incompletion of yolk sac?lack of an inflated swim bladder or hatching delay.(4)The concentration of total petroleum hydrocarbons(TPH)and total polycyclic aromatic hydrocarbons(PAHs)in CEWAF at different dilution rates were all higher than that of WAF at corresponding dilution rates.