Toxicity of the brominated flame retardant tris-(2,3-dibromopropyl) isocyanurate in zebrafish (Danio rerio)

Xu Zhang,Yong Liang,Le Wu,Qunfang Zhou,Jie Zhang,Minjie Chen,Chi Zhang,Juan Li

doi:10.1007/s11434-011-4471-6

Abstract

Tris-(2,3-dibromopropyl) isocyanurate (TBC) is a heterocyclic brominated flame retardant that was recently detected in the environment in China. TBC is semi-volatile and can accumulate in the lipid of some species, but little is known about its effect on aquatic organisms. We exposed adult zebrafish to 0, 0.25, 1 and 4 mg/L TBC for 28 d and measured the effect on survival, growth, histopathology, hormone levels, enzyme activity, and gene expression. TBC exposure had no effect on survival or growth. We observed significant damage to the liver and gill, including hepatocellular swelling and fatty degeneration in the liver as well as proliferation and edema of epithelial cells in the gills. In addition, exposure to 4 mg/L TBC induced proliferation of goblet cells in the intestine of both sexes, acellular areas in the testis, and thinly scattered vitellogenic granules in vitellogenic oocytes. TBC exposure had no effect on the levels of thyroid hormones, testosterone, estradiol, liver superoxide dismutase activity, malondialdehyde content, and brain cholinesterase activity. By contrast, hepatic vitellogenin and cytochrome P4501A gene expression was significantly down-regulated in both male and female zebrafish in response to TBC exposure. Our results suggest that exposure to TBC causes a variety of potential reproductive and endocrine toxic effects.

Highlights

Tris-(2,3-dibromopropyl) isocyanurate (TBC) is a heterocyclic brominated flame retardant that was recently detected in the environment in China
Given that the aquatic environment is the ultimate sink for many pollutants, it is important to understand the likely effects of TBC on aquatic organisms
polybrominated diphenyl ethers (PBDEs) are absorbed through the gill membranes and BDE47 causes apoptosis in the gill epithelial cells of rainbow trout [16,17]

Summary

Introduction

Tris-(2,3-dibromopropyl) isocyanurate (TBC) is a heterocyclic brominated flame retardant that was recently detected in the environment in China. We exposed adult zebrafish to 0, 0.25, 1 and 4 mg/L TBC for 28 d and measured the effect on survival, growth, histopathology, hormone levels, enzyme activity, and gene expression. The concentration of the BFRs has been increasing annually in a range of organisms, including human breast milk [4,5,6]. This has been addressed to some extent by the ban of polybrominated diphenyl ethers (PBDEs) throughout the industrialized world [7]. We exposed adult zebrafish (Danio rerio) to a high, medium, and low dose of TBC for 28 d and evaluated the effect on tissue pathology, hormone levels and enzyme activity

Objectives

Methods

Results

Conclusion