Accumulation and Endocrine Disrupting Effects of the Flame Retardant Mixture Firemaster^® 550 in Rats: An Exploratory Assessment

Abstract

Firemaster® 550 (FM 550), a fire-retardant mixture used in foam-based products, was recently identified as a common contaminant in household dust. The chemical structures of its principle components suggest they have endocrine disrupting activity, but nothing is known about their physiological effects at environmentally relevant exposure levels. The goal of this exploratory study was to evaluate accumulation, metabolism and endocrine disrupting effects of FM 550 in rats exposed to 100 or 1000 μg/day across gestation and lactation. FM 550 components accumulated in tissues of exposed dams and offspring and induced phenotypic hallmarks associated with metabolic syndrome in the offspring. Effects included increased serum thyroxine levels and reduced hepatic carboxylesterease activity in dams, and advanced female puberty, weight gain, male cardiac hypertrophy, and altered exploratory behaviors in offspring. Results of this study are the first to implicate FM 550 as an endocrine disruptor and an obesogen at environmentally relevant levels.

Disposition of the Emerging Brominated Flame Retardant, 2-Ethylhexyl 2,3,4,5-Tetrabromobenzoate, in Female SD Rats and Male B6C3F1 Mice: Effects of Dose, Route, and Repeated Administration

“…Bearr et al (2012) detected EH-TBB in tissues from fathead minnows (Pimephales promelas) 22 days after cessation of FM550 exposure. SD rat dams administered FM550 (1 mg/day) during pregnancy and nursing were observed to have increased serum thyroxine and decreased hepatic esterase activity (Patisaul et al, 2013). Furthermore, in these studies, female pups displayed high anxiety phenotypes whereas male offspring had significantly impaired glucose tolerance.…”

“…Finally, an exploratory assessment of possible species-or sexrelated differences in the disposition of EH-TBB was performed using male B6C3F1/Tac mice in a prior paradigm (Buchanan et al, 1997). The dose range tested herein was based on highrange human exposures to EH-TBB in household dust, as described by Patisaul et al (2013).…”

Levels of Non-PBDE Halogenated Fire Retardants and Brominated Dioxins and their Toxicological Effects in Indoor Environments - A Review

“…The results indicate that the 1.0 mg L -1 dose of FM-550 caused significant malformations in larval zebrafish compared to adolescent zebrafish (Bailey and Levin, 2015). In an in vivo study by Patisaul et al (2013), elevated body weight at a high-dose exposure (1,000 µg day -1 ) was the most significant developmental effect of FM-550 in Wistar rats. This effect became evident prior to adolescence and continued into adulthood for both sexes.…”

“…Studies of acute toxicity in Wistar rats showed that a single dose of 5,000 mg kg -1 FM-550 did not produce lethality, outwardly observable effects, or gross changes at necropsy after 15 days (USEPA, 2015). Experimental data also showed that it was possible for BEH-TEBP to be absorbed after oral exposure with a commercial mixture FM-550 (Patisaul et al, 2013). BEH-TEBP was found in the tissues of pregnant Wistar rats after exposure to the commercial mixture; however, BEH-TEBP was not found in the offspring even though exposure had occurred from gestation to lactation (Patisaul et al, 2013).…”

“…This effect became evident prior to adolescence and continued into adulthood for both sexes. An increase in body weight, especially in the males, was interpreted as a symptom of morbid obesity (Patisaul et al, 2013).…”