Concentrations of polybrominated diphenyl ethers (PBDEs) in matched samples of human milk, dust and indoor air

Abstract

Polybrominated diphenyl ethers (PBDEs) are lipophilic, persistent pollutants found worldwide in environmental and human samples. Exposure pathways for PBDEs remain unclear but may include food, air and dust. The aim of this study was to conduct an integrated assessment of PBDE exposure and human body burden using 10 matched samples of human milk, indoor air and dust collected in 2007-2008 in Brisbane, Australia. In addition, temporal analysis was investigated comparing the results of the current study with PBDE concentrations in human milk collected in 2002-2003 from the same region. PBDEs were detected in all matrices and the median concentrations of BDEs -47 and -209 in human milk, air and dust were: 4.2 and 0.3 ng/g lipid; 25 and 7.8 pg/m(3); and 56 and 291 ng/g dust, respectively. Significant correlations were observed between the concentrations of BDE-99 in air and human milk (r=0.661, p=0.038) and BDE-153 in dust and BDE-183 in human milk (r=0.697, p=0.025). These correlations do not suggest causal relationships - there is no hypothesis that can be offered to explain why BDE-153 in dust and BDE-183 in milk are correlated. The fact that so few correlations were found in the data could be a function of the small sample size, or because additional factors, such as sources of exposure not considered or measured in the study, might be important in explaining exposure to PBDEs. There was a slight decrease in PBDE concentrations from 2002-2003 to 2007-2008 but this may be due to sampling and analytical differences. Overall, average PBDE concentrations from these individual samples were similar to results from pooled human milk collected in Brisbane in 2002-2003 indicating that pooling may be an efficient, cost-effective strategy of assessing PBDE concentrations on a population basis. The results of this study were used to estimate an infant's daily PBDE intake via inhalation, dust ingestion and human milk consumption. Differences in PBDE intake of individual congeners from the different matrices were observed. Specifically, as the level of bromination increased, the contribution of PBDE intake decreased via human milk and increased via dust. As the impacts of the ban of the lower brominated (penta- and octa-BDE) products become evident, an increased use of the higher brominated deca-BDE product may result in dust making a greater contribution to infant exposure than it does currently. To better understand human body burden, further research is required into the sources and exposure pathways of PBDEs and metabolic differences influencing an individual's response to exposure. In addition, temporal trend analysis is necessary with continued monitoring of PBDEs in the human population as well as in the suggested exposure matrices of food, dust and air.

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

“…Six such studies exist for PBDEs (11,54,(95)(96)(97)(98) with one examining HBCDs (21). With two possible exceptions (96,97), study power is limited by small participant numbers.…”

Levels and congener profiles of polybrominated diphenyl ethers (PBDEs) in breast milk from Shanghai: Implication for exposure route of higher brominated BDEs

“…In fact, several groups have performed studies on the exposure routes and the body burden of PBDEs (Johnson et al, 2010;Karlsson et al, 2007;Toms et al, 2009;Wu et al, 2007), and positive correlations were found between PBDEs concentrations in blood/milk and dust. Recently, the U.S. EPA also initiated an exposure assessment of PBDEs and suggested that contact with house dust accounts for between 80 and 90% of total exposures, with the remainder due primarily to food ingestion (U.S. Environmental Protection Agency, 2010).…”

Impact of Brominated POPs on the Neurodevelopment and Thyroid Hormones of Young Children in an Indoor Environment—A Review

“…The estimated ΣPBDE daily intake from dust for children (49.3 ng/kg b.w./day) during the period from 1-5 years old is six time higher than for adults (7.7 ng/kg b.w./day) because of children's lower body weight and higher dust intake (Lorber, 2008). Toms et al (2009) calculates that the ΣPBDE daily intake from dust in children ranges between 33 and 118 ng/day but for adults is only from 2.5 to 59 ng/day.…”

“…A recent study of family members with nonoccupational exposure to PBDEs suggests that toddlers and children have a higher risk of PBDE exposure and face higher risks of PBDE-related health effects than their parents (Fischer et al, 2006). Toms et al (2009) investigates concentrations of PBDEs in matched samples of breast milk, dust, and indoor air to determine if levels are based on congener profiles, as the level of bromination increased the contribution of intake decreased via breast milk and increased via dust and the contribution of inhalation to total PBDE intake was minor. The estimated ΣPBDE daily intake from dust for children (49.3 ng/kg b.w./day) during the period from 1-5 years old is six time higher than for adults (7.7 ng/kg b.w./day) because of children's lower body weight and higher dust intake (Lorber, 2008).…”