Sorption of PBDE in low-density polyethylene film: Implications for bioavailability of BDE-209

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Abstract

The coefficients of partitioning (Kpew) between low-density polyethylene (LDPE) film (50-µm thickness) and water for 23 polybrominated diphenyl ether (PBDE) congeners were determined based on a regression analysis of sorption kinetics over an extended exposure period (up to 365 d). A curvilinear relationship between log Kpew and log KOW (octanol–water partition coefficient) was obtained for the target BDE congeners with the turning point at log KOW approximately 8. Previously obtained dietary uptake efficiencies of BDE congeners in common carp (Cyprinus carpio) were also found to relate curvilinearly to log KOW. In addition, field-measured relative abundances of BDE-209 compiled from previous investigations conducted in the Pearl River Delta of South China were significantly (p < 0.001) higher in abiotic samples (n = 79 from 11 matrices) than in biotic samples (n = 73 from 12 matrices), suggesting the likelihood for reduced bioavailability of BDE-209 in certain biota. Finally, a molecular-scale analysis indicated that the curvilinear relationship between log Kpew and log KOW can be attributed to the energy barrier that a molecule has to overcome as it attempts to diffuse into the LDPE structure, which can become significant for larger molecules. Similarly, the reduced bioavailability of BDE-209 in many biological species can be regarded as a reflection of the magnitude of molecular interactions between cell membranes and BDE-209. Environ. Toxicol. Chem. 2011; 30:1731–1738. © 2011 SETAC

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