|Nomination Rationale and Project Aims|
Due to increased demand and use as an alternative to decabromodiphenyl ether, decabromodiphenylethane is widely detected in indoor and outdoor environments, biota, and consumer products. Subacute and subchronic toxicology studies in rats indicate the liver is a target organ. This compound is included along with other brominated flame retardants as part of a short-term toxicogenomic evaluation.
|Firemaster 550 and constituents: 2-Ethylhexyl-2,3,4,5-tetrabromobenzoate
Isopropylated phenol phosphate
A widely used flame retardant alternative to polybrominated diphenyl ethers, Firemaster 550 is a mixture of brominated aromatic and aromatic phosphate components and has been widely detected in the environment, biota, and indoor dust. Activity at nuclear hormone receptors has been demonstrated from in vitro studies, yet there is very limited in vivo data for the commercial mixture and some of its components. The two phosphate components (115-86-6 and 68937-41-7) are included in the ongoing aromatic phosphate flame retardant research program. The other two components (183658-27-7 and 26040-51-7) are included along with other brominated flame retardants as part of a short-term toxicogenomic evaluation.
Microcystins are among the most common cyanobacterial toxins that contaminate recreational water and drinking water sources, with documented adverse human health effects and a robust literature on hepatotoxicity and mechanisms of action in animal models. There are no long-term rodent toxicity studies and existing data indicate concern for potential adverse effects during sensitive periods of development. NTP has previously conducted toxicogenomic studies following acute exposure. A new study to provide a comprehensive assessment of developmental, reproductive, and general toxicity following subchronic drinking water exposure is under development.