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Tissue distribution of polybrominated diphenyl ethers in male ratsand implications for biomonitoring
Citation:
Huwe, J., H. Hakk, AND L. S. BIRNBAUM. Tissue distribution of polybrominated diphenyl ethers in male ratsand implications for biomonitoring. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 42(18):7018-7024, (2008).
Impact/Purpose:
This was part of the 2006 OMB pilot from OSWER concerning the bioavailability of brominated flame retardants from dust. This paper suggest that measuring the higher brominated PBDEs on a lipid basis, as is usually done, may greatly misrepresent the actual body burden of these chemicals. It may be better to monitor them in serum on a wet weight basis.
Description:
Polybrominated diphenyl ethers (PBDEs) are a class of widely-used flame retardants which have been found to persist, bioaccumulate, and potentially affect development in animals. Exposure to PBDEs can be through both diet and the environment and is generally estimated by measuring PBDEs in blood, adipose tissue, muscle, or milk samples. Using rats as a model, we investigated tissue distribution of PBDEs after oral administration and evaluated a suitable matrix for body burden estimation. Male rats were administered dust or corn oil containing 8 or 6 µg PBDEs kg-1 body wt, respectively, in the diet for 21 days (N = 4 rats per treatment), and the concentration of 15 PBDEs were measured in various tissues, plasma, and feces. PBDEs were found in all tissues, including the brain, and showed no difference in distribution patterns between treatments for most PBDEs. Tri- to hexa-BDEs comprised >80% of the total PBDEs in the adipose, brain, kidney, lung, and residual carcass, but <40% in the liver and plasma. The ratio of the lipid-weight concentration of tri- to hexa-BDEs in adipose tissue, residual carcass, and plasma was 1:1:2. For the hepta- to nona-BDEs, lipid-weight concentrations increased from adipose tissue to residual carcass to plasma in the ratio 0.3:1:>4. BDE-209 was the dominant congener in the liver and plasma, but was not detected in the adipose tissue or carcass. In summary, the lower brominated congeners tended to distribute equally into lipids implying both adipose tissue and plasma would be suitable matrices for biomonitoring. Plasma was the best matrix for detection of the higher brominated congeners (especially BDE-209), although on a lipid-weight basis tended to over-estimate the total body burdens.
