Bioaccumulation of polybrominated diphenyl ethers by Tubifex tubifex

Abstract

Selective uptake of PBDEs by oligochaete allows the assessment of the bioaccumulation of individual congeners in commercial mixtures. 21 congeners from three BDE commercial mixtures (TBDE-71, TBDE-79 and TBDE-83R) and as individual congeners (BDE-77, BDE-126, BDE-198 and BDE-204) were tested on Tubifex tubifex according to the OECD TG 315 “Bioaccumulation in Sediment-dwelling Benthic Oligochaetes”. All congeners that were spiked on the sediment were detected at the end of the uptake phase and at the end of the experiment. The bioaccumulation factor (BAF), kinetic bioaccumulation factor (BAF_K) and biota-sediment accumulation factor (BSAF) were calculated, indicating a high bioaccumulation potential for tri-to hexa-BDEs and lower hepta- to deca- BDEs. Penta-homologues BDE-99 and BDE-100 showed the highest BSAF of 4.84 and 5.85, while the nona- and deca- BDEs exhibit the bioaccumulation in up to one order lower concentrations. The change in the bioaccumulation potential between group of tri- to hexa-BDEs and hepta- to deca-BDEs correlated with generally accepted molecular mass threshold for the molecular transition through biological membranes (700 g/mol).