Gastrointestinal absorption, metabolic debromination, and hydroxylation of three commercial polybrominated diphenyl ether mixtures by common carp

Abstract

Abstract-The gastrointestinal absorption, metabolic debromination, and hydroxylation of three commercial brominated diphenyl ether (BDE) mixtures were separately studied in juvenile common carp. The absorption rate of penta-BDE was higher than that of octa-and deca-BDE, likely because of the lower molecular volumes of its major congeners. However, no significantly positive relationships were found between the number of bromine atoms and the absorption rate, especially for congeners with a bromine atom number larger than six. The major congeners in fish carcass were, respectively, BDE-47 and BDE-100 in the penta-BDE exposure; BDE-154, -155, -149, and BDE-153 in the octa-BDE exposure; and in the deca-BDE exposure. Congeners with at least one meta-or para-doubly flanked bromine atom easily undergo metabolic debromination in fish. None of the targeted MeOpolybrominated diphenyl ether (PBDE) congeners were detected in serum samples, implying that the methylation of OH-PBDE is not likely occurring in fish. Eleven OH-PBDEs and several unidentified OH-PBDE congeners were found in penta-BDE-exposed fish. The similar level among three mono-OH-BDE47 congeners suggested that the position of OH in the phenyl ring is not selective. The hydroxylation is not a significant metabolic pathway compared with debromination. No OH-PBDE congeners were found in the serum samples from deca-BDE-exposed fish, which may attributable to the low level of PBDE precursors in fish. Environ. Toxicol. Chem.

Separation of polybrominated diphenyl ethers in fish for compound-specific stable carbon isotope analysis

“…This finding suggests that the increased abundance of BDE-47 in fish was a result of the debromination of BDE-99. As for BDE-100, its relative contribution to the total PBDE in Penta-BDE was similar to its contribution in the fish carcasses (8.2% vs. 8.4%) (Zeng et al, 2012), indicating a constant δ 13 C value before and after the exposure experiments. In brief, this study verified the applicability of CSIA for determining the fate of PBDEs in biota.…”

“…The abundance of BDE-47 compared to total PBDEs increased from 30% in the Penta-BDE mixture to 85% in fish, whereas the contribution of BDE-99 to total PBDE decreased from 47% in the Penta-BDE mixture to 0.47% in fish (Zeng et al, 2012). A previous study conducted by Stapleton et al (2004) demonstrated that common carp can transform BDE-99 to BDE-47.…”

“…The carp (30 fish) were exposed to the Penta-BDE mixture at a dose of 100 ± 10 μg/day/fish for 20 days. Detailed information regarding the feeding of carp in the laboratory has been provided previously (Zeng et al, 2012). The carcasses of every five fish were pooled into one sample, resulting in six composite samples.…”

“…These samples were used for PBDE analysis and stable carbon isotope analysis. The control experiment was conducted during whole expose experiment and the results have been provided in details in our previous publication (Zeng et al, 2012) and were not present herein.…”

“…One tenth of the extracts of fish carcasses was used to quantify the PBDE congeners using a method described in detail previously (Zeng et al, 2012;Yu et al, 2011). The remaining extracts were used to determine purities and to perform CSIA using the method developed in the present study.…”