Exposure of Americans to polybrominated diphenyl ethers

Abstract

Polybrominated diphenyl ethers, PBDEs, are a class of brominated flame retardants that, like other persistent organic pollutants (POPs), have been found in humans, wildlife, and biota worldwide. Unlike other POPs, however, the key routes of human exposure are not thought to be food and fish, but rather are from their use in household consumer products, and to the high levels of PBDEs found in house dust. The exposure of Americans to PBDEs was systematically evaluated in this study. First, exposure media data on PBDE congeners were compiled. Then, an adult intake dose was derived using exposure factors in combination with these data. The exposure pathways evaluated included food and water ingestion, inhalation, and ingestion and dermal contact to house dust. These intakes were converted to a body burden using a simple pharmacokinetic (PK) model. The predicted body burdens were compared with representative profiles of PBDEs in blood and milk. The adult intake dose of total PBDEs was estimated to be 7.7 ng/kg body weight/day, and children's estimated intakes were higher at 49.3 ng/kg/day for ages 1-5, 14.4 ng/kg/day for 6-11, and 9.1 ng/kg/day for 12-19. The much higher dose for the child age 1-5 was due to the doubling of dust ingestion from 50 to 100 mg/day. The predicted adult body burden of total PBDEs was 33.8 ng/kg lipid weight (lwt), compared to representative measurements in blood and milk at 64.0 and 93.7 ng/g lwt, respectively Most of this apparent underprediction in total concentration was due to an underprediction of the key congener, BDE 47. The value for BDE 47 half-life in the body was identified as the variable most likely in error in this exercise. Other congener predictions compared well with measurements, suggesting general validity with the approach. An important finding from this assessment is that the food intake estimate of about 1.3 ng/kg/day (of the 7.7 ng/kg/day total) cannot explain current US body burdens; exposures to PBDEs in house dust accounted for 82% of the overall estimated intakes.

Determination of polybrominated diphenyl ethers in human semen

“…Furthermore, the PBDE burden of these patients was much lower than among occupational workers (with a mean PBDEs of 600 ng/g lipid) from Guiyu, as reported by Bi et al (2007). Nevertheless, the level of PBDE burden in the patient population was higher than those in the general European and Asian populations, which were generally below 5 ng/g lipid (Furst, 2006;Inoue et al, 2006;Lorber, 2008;Schecter et al, 1996Schecter et al, , 2003). Generally, North Americans tend to have higher body burdens of PBDEs than Europeans and Asians (Hites, 2004;Sjödin et al, 2003;Wang et al, 2007).…”

Indoor Contamination with Hexabromocyclododecanes, Polybrominated Diphenyl Ethers, and Perfluoroalkyl Compounds: An Important Exposure Pathway for People?

“…It was thus concluded that dust ingestion constitutes the principal exposure pathway to ΣPBDEs (BDEs 28, 47, 99, 100, 138, 153, 154, 183, and 209) for Americans (83). In addition, this pharmacokinetic modeling approach provides a conceptual framework for understanding relationships between exposure and body burden and for identifying knowledge gaps.…”

“…In addition, this pharmacokinetic modeling approach provides a conceptual framework for understanding relationships between exposure and body burden and for identifying knowledge gaps. While for PBDEs, parameters C, Vd, and D (for dietary intake) are well-characterized, aspects where understanding is incomplete are congener-specific human elimination rate constants (an overerestimate of the elimination rate constant for BDE-47 was identified as the likely cause of the substantial underprediction of this congener (83)), the scant database on human body burdens of BDE-209, and the reliance on the assumption that human body burdens are at steady state. Other uncertainties exist.…”

Serum levels of decabromodiphenyl ether (BDE-209) in women from different European countries and possible relationships with lifestyle and diet

“…Recently, adult exposure to PBDEs, 29 including BDE-209, in the US was summarized and the daily uptake was estimated to be about 30 2 ng/kg/day for an adult of 70 kg. Daily intake for US children aged 1-5, 6-11 and 12-19 years 31 was estimated significantly higher, respectively 49, 14 and 9 ng/kg/day (Lorber 2008). Even 32 with the higher infant exposure levels the MOE with the RfD still remains above a factor 100.…”