Toxic Effects Of Tetrabromobisphenol A (TBBPA) On Fish

Tetrabromobisphenol-A(TBBPA)is the most widely used brominated flame retardants(BFRs)all over the world,and has been found in environmental and biological specimen.TBBPA expecially shows strong acute toxicity to aquatic organisms such as fish.However,no solid conclsuions can be drawn on thyroid hormone disrupting effects of TBBPA in vivo in fish.Furthermore,little data is available for the reproductive toxicity,neurotoxicity and etc.In present study,zebrafish(Danio rerio)were exposed to 0,0.01,0.05 and 0.1 mg·L^-1tetrabromobisphenol-A(TBBPA)for 21 and 42 days.The histological structure of thyroid gland and liver were observed.TBBPA increased the height of the follicular epithelium,and induced thyroid epithelial cell hypertrophy and hyperplasia. The histology of adult ovaries showed a relative increase of premature oocytes after exposure to TBBPA.Abnormal testis with severe spermaduct malformation was also observed.These results indicated that TBBPA might change the histological structure of thyroid and gonad.In the same experiment above,the histological and ultramicro structure were observed in the liver of zebrafish.The section of liver showed vacuolization, amplification,cell atrophy and nuclear deformation phenomena in treatment groups. Cell spaces,mitochondrial inner membranization and rough endoplasmic reticulum significantly increased in liver after 42 days exposure.The results indicated that TBBPA also changed the structure of liver in fish.In addition,goldfish(Carassius auratus)were exposed to 0.01,and 0.1 mg·L^-1 TBBPA for 28 days.The activities of acetylcholinesterase(ACHE)in both brain and liver were slightly inhibited.The activity of monoamine oxidasein(MAO)was increased in a small part of the sampling points in brain,while it was decreased in a small part of the sampling points in liver.Therefore,no obvious points could be stated on the neurotoxicity from the present study.In brief,these results indicated that TBBPA could affect the thyroid system and reproductive system in fish and damage the liver.Furthure study is needed in neurotoxicity of TBBTP in fish.Due to the multiple-targets and multiple-modes of action of TBBPA,it is highly recommended that a combined effect ofa sigle contaminant should be considered in the the risk assessment of TBBPA.