Toxicology studies of a pentabromodiphenyl ether mixture [DE-71 (technical grade)] in F344/N rats and B6C3F1/N mice and toxicology and carcinogenesis studies of a pentabromodiphenyl ether mixture [DE-71 (technical grade)] in Wistar Han [Crl:WI(Han)] rats and B6C3F1/N mice (gavage studies).

Abstract

DE-71, a pentabromodiphenyl ether mixture, was used in the past as an additive flame retardant, often in furniture materials. Additive flame retardants are mixed into products, but they are not covalently bound to the polymers in the commercial products, and thus can leach out into the environment. Though use and sale of polybrominated diphenyl ethers (PBDEs) was banned in the European Union and production was voluntarily phased out in the United States around 2004, they remain in the environment as products produced before use was discontinued or as discarded products. PBDEs can be found in water, wildlife, and in humans, as well as in various food products including meat, poultry, and fish. The California Office of Environmental Health Hazard Assessment nominated individual PBDE congeners for study because they were considered a health risk and have been found in human and animal tissue in the United States. Because of limited availability of the individual PBDE congeners, DE-71, the flame retardant used in furniture, was evaluated in rats and mice to characterize the toxic and carcinogenic potential of PBDEs. Male and female F344/N rats and B6C3F1/N mice were administered DE-71 in corn oil by gavage for 3 months. Wistar Han [Crl:WI(Han)] dams (referred to as Wistar Han rats) were administered DE-71 in corn oil by gavage from gestational day (GD) 6 through postnatal day (PND) 20. Their pups were administered the same doses in corn oil by gavage from PND 12 through 2 years. Male and female B6C3F1/N mice were administered DE-71 in corn oil by gavage for 2 years. Genetic toxicology studies of DE-71 as well as three individual PBDEs were conducted in Salmonella typhimurium and Escherichia coli, mouse bone marrow cells, and mouse peripheral blood erythrocytes. (Abstract Abridged).