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BIOAVAILABILITY OF PBDES IN MALE RATS FROM ORALLY ADMINISTERED HOUSEHOLD DUST
Citation:
HAKK, H., J. K. HUWE, J. J. DILIBERTO, H. M. STAPLETON, AND L. S. BIRNBAUM. BIOAVAILABILITY OF PBDES IN MALE RATS FROM ORALLY ADMINISTERED HOUSEHOLD DUST. Presented at Society of Toxicology Annual Meeting, Charlotte, NC, March 25 - 29, 2007.
Description:
Recently, household dust has been implicated as a major source of polybrominated diphenyl ether (PBDE) exposure in humans. This finding has very important implications especially for young children, who are thought to ingest more dust than adults, and may be more susceptible to some of the putative developmental effects of PBDEs. No absorption parameters of PBDEs from ingested dust have ever been determined, therefore, the objectives of this study were to determine the absorption, distribution, and excretion of PBDEs in male Sprague-Dawley rats fed either dust (NIST Standard Reference Material 2585) or oil contaminated with ppb levels of 20 PBDE congeners for 21 days in the diet. Following cleanup by an automated Fluid Management System utilizing triphasic silica and basic alumina cartridges, the tissue residues were quantitated by HR-GC/HR-MS analysis. Results from adipose tissue and livers showed that uptake of individual PBDE congeners did not differ between comparable doses of either vehicle. Bioconcentration factors of PBDEs in adipose were the same for all dosage groups, i.e. 10-20 for tri- to hexa-BDEs, 1-4 for hepta- to nona-BDEs, and <1 for deca-BDE. The liver-to-adipose ratios on a lipid-weight basis (L:A) for tri- to hexa-BDEs were <0.5, while the L:A was >1.0 for hepta- to deca-BDEs. The present results show that PBDEs in dust are at least as bioavailable as those dissolved into an oil vehicle, and that higher brominated congeners are less bioavailable than lower brominated congeners. These results indicate that dust can be a facile source of PBDEs in mammals, and that the familiar PBDE fingerprints in biota is a result, at least in part, of bioavailability of individual congeners. (This abstract does not reflect Agency policy.)