Abstract
The selective uptake of polybrominated diphenyl ethers (PBDEs) by oligochaetes makes it possible to assess the bioaccumulation of individual congeners in commercial mixtures. Twenty-one 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 in accordance with the OECD TG 315 "Bioaccumulation in Sediment-Dwelling Benthic Oligochaetes". All the congeners that were spiked in the sediment were detected at the end of the uptake phase and at the end of the experiment. The bioaccumulation factor (BAF), the kinetic bioaccumulation factor (BAFK) and the biotasediment accumulation factor (BSAF) were calculated, and indicate a high bioaccumulation potential for tri- to hexa-BDEs and a lower bioaccumulation potential for hepta- to deca-BDEs. The penta-homologues BDE-99 and BDE-100 showed the highest BSAFs of 4.84 and 5.85 (BAFs of 7.34 and 9.01), while the nona- and deca-BDEs exhibit bioaccumulation in up to one-order-lower concentrations. The change in the bioaccumulation potential between the group of trito hexa-BDEs and hepta- to deca-BDEs correlated with the generally accepted molecular-mass threshold for the molecular transition through biological membranes (700 g/mol).
Highlights
Polybrominated diphenyl ethers (PBDEs) have been used as flame retardants for a large number of synthetic applications, such as building materials, furnishing textiles, and electronic equipment, in order to reduce the risk of fire.[1]
The main endpoint of the test according to OECD TG 315 was the bioaccumulation factor (BAF) as the ratio between the concentration of the contaminant in the tested animal and the concentration of the contaminant in the sediment
The bioaccumulation kinetics during 28 days of uptake and 12 days of elimination of the BDEs was plotted against the time course
Summary
Polybrominated diphenyl ethers (PBDEs) have been used as flame retardants for a large number of synthetic applications, such as building materials, furnishing textiles, and electronic equipment, in order to reduce the risk of fire.[1]. The bromines substituted at positions 1 to 10 allow, in theory, 209 congeners.[2] PBDEs are categorized by their degree of bromination, where the term homologue is used to refer to a group of PBDEs with the same number of bromines (PBDEs containing five bromine atoms are, for example, referred to as penta-BDEs). Based on the number of bromine substituents, there are 10 homologous groups of PBDEs (monobrominated through deca-brominated homologues).[3] Historically, three major PBDE products have been commercially available on the global market, i.e., the penta-, octaand deca-BDEs.[4] The commercial products are not pure substances; rather they are mixtures of congeners. In contrast to the commercial penta- and octa-BDEs products, commercial deca-BDE is a relatively pure mixture, composed predominantly of deca-BDE5.
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