Advance in researches on the transport and transformation of polybrominated diphenyl ethers in environment

Polybrominated Diphenyl Ethers(PBDEs) is a type of additive brominated flame retardant that is widely used in the world.It is recognized that PBDEs are highly lipophilic,hard to degrade,bioaccumulative and highly toxic.To undergo the risk assessment of PDBEs,the mechanisms about transport and transformation of PBDEs in environment should be elucidated.In this paper we reviewed the current status regarding the distribution,transport and transformation of PBDEs in different environmental compartments,including factors influencing photolysis and biodegradation.Results showed that less brominated diphenyl ethers in gas phase dominated in atmosphere,while highly brominated congeners usually existed on particles.Therefore,less brominated diphenyl ethers had stronger long-range transport potential than highly brominated congeners.The concentration of PBDEs in water was very low and most of them accumulated in sediments and biota that would seriously harm the high trophic animals in food chain.Photolysis and biodegradation were two important transformations of PBDEs.For the part of PBDEs in shallow water and atmosphere,photolysis was the main manner and for the part in deep water and sediments,biodegradation played a dominant role.Finally,the future study of PBDEs was brought forward in this paper.