Ecotoxicity and biodegradability of new brominated flame retardants: a review.

Brominated flame retardants (BFRs) have been routinely used as additives in a number of consumer products for several decades in order to reduce the risk of fire accidents. Concerns about the massive use of these substances have increased due to their possible toxicity, endocrine disrupting properties and occurrence in almost all the environmental compartments, including humans and wildlife organisms. Several conventional BFRs (e.g. polybrominated diphenylethers (PBDE)) have been included in the list of Persistent Organic Pollutants and their use has been restricted because of their established toxicity and environmental persistence. Over the past few years, these compounds have been replaced with "new" BFRs (NBFRs). Despite the fact that NBFRs are different chemical molecules than traditional BFRs, most of physical-chemical properties (e.g. aromatic moiety, halogen substitution, lipophilic character) are common to both groups; therefore, their fate in the environment is potentially similar to the banned BFRs. Therefore, this article has been compiled to summarize the published scientific data regarding the biodegradability of the most widely used NBFRs, a key factor in their potential persistency in the environment, and their ecotoxicological effects on humans and test organisms. The data reviewed here document that the mechanisms through NBFRs exibit their ecotoxicity and the processes leading to their biotransformation in the environment are still poorly understood. Thus emphasis is placed on the need for further research in these areas is therefore emphasized, in order to avoid the massive use of further potentially harmful and recalcitrant substances of anthropogenic origin.

Hormonal activities of new brominated flame retardants.

After the phase-out of two commercial mixtures of brominated flame retardants, an increasing number of alternative flame retardants have been introduced in commercial applications. None of them, however, has been thoroughly tested for its hormonal activity. We used two yeast reporter-gene assays to determine the potential of eleven compounds to interfere with estrogenic and androgenic pathways. Our data demonstrate the ability of 2,4,6-tribromophenol to lower the transcriptional activity of human estrogen and androgen receptors. A nominal IC(50) value of 14.1 µM for anti-estrogenic and 3.9 µM for anti-androgenic activity was obtained using the luciferase reporter. An IC(50) value of 9.2 µM was calculated for the anti-estrogenic activity measured by the ß-galactosidase assay. Of the tested chemicals, this study highlights the endocrine disrupting effects of 2,4,6-tribromophenol whose occurrence in the environment should be monitored.