Uptake, biotransformation and physiological response of TBBPA derivatives in Helianthus annus

Abstract

Tetrabromobisphenol A (TBBPA) and its derivatives are widely used as brominated flame retardants. Because of their high production and wide environment distribution, TBBPA derivatives have increased considerable concern. Previous studies have primarily focused on TBBPA, with limited information available on its derivative. In this study, we investigated the uptake, biotransformation and physiological response of two derivatives, Tetrabromobisphenol A bis(allyl ether) (TBBPA BAE) and Tetrabromobisphenol A bis(2,3-dibromopropylether) (TBBPA BDBPE), in Helianthus annus (H. annus) through a short-term hydroponic assay. The results revealed that H. annus could absorb TBBPA BAE and TBBPA BDBPE from solution, with removal efficiencies of 98.33 ± 0.5% and 98.49 ± 1.56% after 10 days, respectively, which followed first-order kinetics. TBBPA BAE was absorbed, translocated and accumulated while TBBPA BDBPE couldn't be translocated upward due to its high hydrophobicity and low solubility. The concentrations of TBBPA derivatives in plants peaked within 72 h, and then decreased. We identified twelve metabolites resulting from ether bond breakage, debromination, and hydroxylation in H. annus. The high-level TBBPA BAE suppressed the growth and increased malondialdehyde (MDA) content of H. annus, while TBBPA BDBPE didn't pose a negative effect on H. annus. TBBPA BAE and TBBPA BDBPE increased the activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), with higher levels of these enzymes activity found in high concentration treatments. Contrastingly, TBBPA BAE exhibited higher toxicity than TBBPA BDBPE, as indicated by greater antioxidant enzyme activity. The findings of this study develop better understanding of biotransformation mechanisms of TBBPA derivatives in plants, contributing to the assessment of the environmental and human health impacts of these contaminants.