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Bioaccumulation and Effects of the Alternative Flame Retardant, Bis(2-ethylhexyl) tetrabromophthalate (TBPH), in Atlantic killifish, Fundulus heteroclitus
Citation:
Nacci, D., B. Clark, M. LaGuardia, K. Miller, D. Champlin, I. Kirby, A. Bertrand, Saro Jayaraman, W. Huang, AND A. Biales. Bioaccumulation and Effects of the Alternative Flame Retardant, Bis(2-ethylhexyl) tetrabromophthalate (TBPH), in Atlantic killifish, Fundulus heteroclitus. Society of Toxicology (SOT) 57th Annual Meeting and ToxExpo, San Antonio, TX, March 11 - 15, 2018.
Impact/Purpose:
This abstract for poster presentation describes an experimental study that contributes to our understanding of the ecological risks associated with exposure to alternative flame retardant chemicals. This broad category of chemicals replaces legacy brominated flame retardant compounds, which were withdrawn from US markets due to environmental and human health concerns; yet the risks associated with these alternative chemicals are not currently well-known. The report focuses on one specific high production, Agency high priority compound, providing background information on environmental occurrence, toxic mechanisms and effects reported in the scientific literature. This information provides context for the experimental results that describe the extent to which the compound was taken up by fish (bioaccumulated) and how fish were adversely affected by this contamination. General impacts from this contribution include improved understanding by managers and scientists of links between human activities, natural dynamics, ecological stressors and ecosystem condition.
Description:
Bis(2-ethylhexyl) tetrabromophthalate (TBPH), is a high production volume chemical classified as an alternative flame retardant (FR), which replaces legacy FRs withdrawn from US markets dues to health and environmental concerns. This study provides experimental data on the bioaccumulation and biological effects from dietary exposure to TBPH of an estuarine fish, Atlantic killifish, Fundulus heteroclitus. Briefly, individually tagged male and female adult fish were fed a gel-based diet amended with carrier or contaminant for 28 days, followed by 14 days consuming uncontaminated food. Dietary amendments were designed to resemble prior studies of fish dietary exposures to TBPH (TBPH_LO diet, 150 µg/g dry weight (dw) and TBPH_HI diet, 1500 µg/g dw) or polychlorinated biphenyls (PCB153 diet, 15 µg/g dw), which was included as a positive control for dietary bioaccumulation. As expected, a large proportion of total dietary PCB153 offered over 28 days was accounted for in fish tissues (~24 %), while a far lower proportion of TBPH was bioaccumulated (<0.5 %). Despite low bioaccumulation, TBPH tissue concentrations achieved were ~ 2- (TBPH_LO) to 20- (TBPH_HI) fold higher than those measured in a limited number of reports of TBPH in field-collected biota. Modeled estimates suggest that about 50% of the measured bioaccumulation occurred by about 12 days, while 50% depuration took about 22 days; there was no size or sex bias in the rates of incorporation or loss of TBPH from fish tissue. Over the course of the experiment (42 d), male fish grew (~0.5 % body dw/d) but female fish did not; unexpectedly, reproductive condition (gonad:body weight ratios) declined in both sexes, independent of treatment. Results demonstrate that extremely high dietary concentrations of TBPH can contaminate fish tissues above the highest levels observed in the environment to date, although these exposures produced few adverse biological effects on adult fish. Future research will characterize potential effects on early developmental and reproductive processes not captured here.