Enantiomer-specific bioaccumulation and depuration of hexabromocyclododecanes in zebrafish (Danio Rerio).

The bioaccumulation and depuration of six hexabromocyclododecane enantiomers in zebrafish were investigated through dietary exposure. The bioaccumulation of (±)α-HBCD, (±)β-HBCD and (±)γ-HBCD was concentration dependent. The results from their concentration trends and assimilation efficiencies suggested that zebrafish selectively bioaccumulate the (+) α-enantiomer and (+) γ-enantiomer compared to their corresponding (-)-enantiomers. However, (±)β-HBCD did not show enantioselectivity in the process of bioaccumulation. The depuration of all six enantiomers in zebrafish followed first-order kinetics except (-)γ-HBCD in low dose. These results showed that the bioaccumulation and depuration of HBCDs in zebrafish were enantiomer-selective. Each enantiomeric pair of HBCDs could display different biological process in organisms.