Brominated flame retardants have come into common use in the United States during the past 3 decades. This study reports levels of polybrominated diphenyl ether (PBDE) flame retardants in blood from the U.S. population at the present time and 30 years previously and also current human milk levels. This is also the first study to report measured congeners and dioxin toxic equivalents (TEQs) of dioxins, dibenzofurans, and dioxin-like polychlorinated biphenyls (PCBs) from archived, 1973, blood and compare them with current levels. The findings indicate there have been significant changes in levels of each class of these persistent organic pollutants (POPs) in U.S. human blood. Although dioxin, dibenzofuran, and PCB levels are markedly higher in the 1973 blood, the opposite is true for PBDEs. Furthermore, unlike dioxins, dibenzofurans, and PCBs, which increase with age, there was no significant correlation found in our study between PBDE levels and age. Current total PBDE levels in U.S. blood are the highest reported worldwide to date, with 2 pooled samples (N = 100 each) measuring 61.7 and 79.7 parts per billion (ppb) lipid, and in a series of 39 individual analyses, the range was 4.6 to 365.5 ppb with a median of 29 ppb and a mean of 52.6 ppb. The median for women in this study was 43.3 ppb, and for men it was 25.1 ppb. Although women have a higher level of PBDEs in blood than men, in our study, this is not statistically significant. Blood levels are similar to levels in U.S. human milk from 59 women, 6.2 to 418.8 ppb lipid. Levels of PBDE in pooled 2003 serum are far higher at 61.7 ppb than in 1973 archived pooled serum in which almost no PBDEs were quantified, although the estimated level using half the detection limit for nondetects was 0.77 ppb. Although no human health studies have been conducted on PBDEs, they are of concern because in vivo and in vitro animal studies show nervous system, reproductive, developmental, and endocrine effects, as well as cancer in high-dose studies.

Polybrominated diphenyl ether (PBDE) brominated flame retardants have recently been found to contaminate humans in the United States and other countries. U.S. human breast milk and blood levels of PBDEs are presently the highest in the world. U.S. cord blood samples tested positive for PBDEs, but until now there have been no peer-reviewed published data concerning levels of PBDEs in human tissue prior to and immediately after birth. Liver tissues were obtained from 4 stillborn fetuses and 7 liveborn infants, ranging from 20.5 to 39 wk gestational age; only 2 of the liveborn infants lived longer than 4 h and none were formula-fed or nursed, so tissue levels reflect intrauterine PBDE intake only. All samples were contaminated with PBDEs. Levels varied from 4 to 98 ppb, lipid. The mean level was 23.1 and the median 15.2 ppb, lipid. PBDE levels did not increase with gestational age. These data document the transfer of PBDEs from maternal to fetal tissue. PBDE concentrations are somewhat lower than those reported in adult blood or breast milk. The health consequences of prenatal contamination are not clear at present.

Polybrominated diphenyl ethers (PBDEs) are brominated flame retardants (BFRs) which have recently been detected in human blood and milk in the USA, and presently these PBDE levels are found to be the highest globally. On a population basis, individual blood and individual milk analyses show similar congener patterns and levels. Until now, there has not been a study comparing PBDE levels in milk and blood of the same individuals. This study is the first to report these levels for PBDEs, though partitioning between blood and milk has been done previously for dioxins and polychlorinated biphenyls (PCBs). Twelve congeners in 11 nursing mothers' blood and milk were found and the data describe partitioning ratios between blood and milk. The data suggest it may be easier for smaller, less brominated congeners to move from blood to milk.

In newly studied locations in Vietnam, we found some persons with elevation of TCDD consistent with exposure to dioxin from Agent Orange. In our previous studies, we found PCBs, PCDDs, and PCDFs as well as pesticides in human milk, blood, or in food. Health effects from Agent Orange need to be differentiated from effects caused by chemicals other than TCDD from Agent Orange.