Human exposure to PBDEs: associations of PBDE body burdens with food consumption and house dust concentrations

Flame-retardants and other organohalogens detected in sewage sludge by electron capture negative ion mass spectrometry

Numerous halogenated organic compounds have been identified as pollutants of concern. Those with high persistence and hydrophobicity may concentrate in biota, sediments, and wastewater sludge. Nonetheless, the release to the environment of many remains largely unrecognized. Stabilized sewage sludge (biosolids) is increasingly being land-applied as a soil amendment. However, understanding the risks of land application has been hampered by the compositional complexity of biosolids. Compound specific analytical approaches may also underestimate environmental impact of land application by overlooking additional contaminants. However, utilizing an alternative analytical approach based on compound functional group (i.e., alkyl halides) enhanced the information content of the analysis. To illustrate, 49 organohalogens were observed by gas chromatography with electron capture negative ionization mass spectrometry in sewage sludge; 23 identified as flame-retardants: that is, PBDEs, hexabromocyclododecane, 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB), 2-ethylhexyl tetrabromophthalate, decabromodiphenyl ethane, 1,2-bis (2,4,6-tribromophenoxy) ethane and Dechlorane Plus. Concentrations ranged from 25 to 1,600,000 ng g(-1) total organic carbon. An additional 16 compounds were tentatively identified as triclosan, chlorinated-methoxy triclosan, chlorinated pesticides, hexachlorobiphenyl, TBB degradation products, brominated furans and nonabromochlorodiphenyl ethers. Such an analytical approach may enhance evaluations of the risks associated with biosolids land-application and assist in prioritizing specific chemicals for future environmental fate and toxicology studies.

Distribution and fate of polybrominated diphenyl ethers in indoor environments of elementary schools

Polybrominated diphenyl ethers (PBDEs) are considered harmful to human health because of their toxicities and persistence in environments. In the current study, the distribution and fate of PBDEs in classrooms and computer rooms in 17 elementary schools in South Korea have been described. Eight congeners (brominated diphenyl ether-28, -47, -99, -100, -153, -154, -183, and -209) in air, floor dust, and product surface dust were measured. While Sigma(8)PBDEs in the air in classrooms showed considerable variations (0.659-1600 pg/m(3), arithmetic mean +/- s.d.: 377 +/- 441 pg/m(3)), those in computer rooms were somewhat similar (134-220 pg/m(3), arithmetic mean +/- s.d.: 169 +/- 40 pg/m(3)). Sigma(8)PBDEs in floor dust varied over a wide range, from 453 to 45,700 ng/g, for all rooms. Based on congener patterns, two groups were created--CL-1 that is dominated by high-brominated congeners and CL-2 primarily comprising low-brominated congeners--for both air and floor dust of classrooms. Surface dust had low concentrations, ranged from ND to 181, from ND to 128, and from ND to 256 pg/cm(2) for desk/chair sets, lockers, and playing tools, respectively. Pearson correlation coefficients were calculated individually for air, floor dust, and surface dust. The results indicate that both surface dust and floor dust may act as a secondary source of PBDEs in indoor environments after emission from facilities.

PRACTICAL IMPLICATIONS

Children have been estimated to have a higher potential exposure to PBDEs than adults. Since children spend most of their day time at school, PBDE distributions in school environments should be a matter of great concern.

Polybrominated diphenyl ethers and synthetic musks in umbilical cord serum, maternal serum, and breast milk from Seoul, South Korea

Fetal and maternal exposure levels of two emerging pollutants, polybrominated diephenyl ethers (PBDEs) and synthetic musks, were measured in Korean general population to assess prenatal and postnatal exposures in infants. For this purpose, paired samples of breast milk, maternal and cord blood were collected from 20 Korean women in 2007. In comparison to data from other countries and previous data from Korea, relatively higher and gradually increasing concentrations for PBDEs were found in Korean breast milk (< LOQ to 590 ng g(-1) lipid wt; median=90 ng g(-1)). Differences in PBDEs and musk concentrations were found among age groups and parity levels. PBDEs concentrations in breast milk were lower in the younger mothers and/or the mothers with multiple parities, while these trends were not found for musks. Compared with PBDEs, concentrations of musks were significantly lower in breast milk than in serum and a little correlation in concentrations among the three human biological matrices were observed. The differences in the profiles of musks relative to PBDEs were due to different clearance rates between these two compounds. The average hazard quotients (HQs) for daily intake of PBDEs by infants via lactation were 0.62, 0.42, and 0.19 for BDE-47, BDE-99, and BDE-153, respectively.

Polybrominated diphenyl ethers in paired samples of maternal and umbilical cord blood plasma and associations with house dust in a Danish cohort

Brominated flame retardants (BFRs), in particular the polybrominated diphenyl ethers (PBDEs), have been used in consumer products for many years to increase fire resistance. Recently, developmental neurotoxicity at very low levels has increased the concern about these compounds. The major objectives of this study were to investigate the maternal and fetal exposure to PBDEs on the basis of maternal and umbilical cord plasma samples and to study the extent of placental transfer for different PBDE congeners. The findings were also compared with previously observed PBDE levels and patterns determined in placental tissue from the same individuals, and the relationship with the external exposure from house dust from the participants' homes was explored. Samples of maternal and umbilical cord plasma from a cohort of 51 pregnant women from the Copenhagen area were collected. Paired maternal and umbilical cord plasma were analysed for BDE-28, 37, 47, 85, 99, 100, 119, 138, 153, 154, 183, 209 and the brominated biphenyl BB-153 using automated SPE extraction and GC-HRMS for the tri- to hepta-BDEs and GC-LRMS (ECNI) for BDE-209. PBDEs were detected in all maternal and umbilical cord plasma samples. The sum of tri- to hexa-BDEs (SigmaPBDE) in maternal plasma varied between 640 and 51,946 pg/g lipid weight (lw) with a median level of 1765 pg/g lw. In the umbilical cord samples SigmaPBDE varied between 213 and 54,346 pg/g lw with a median of 958 pg/g lw. The levels observed in fetal and maternal plasma were highly correlated, but the placental transport of PBDE congeners was found to decrease with increasing diphenyl ether bromination. Maternal concentrations were significantly correlated (p<0.05) for most congeners with the previously determined concentrations in placental tissue from the same individuals. Furthermore, positive correlations (p<0.05) were found for BDE-28, 47, 100, 209 and SigmaPBDE in maternal plasma and house dust as well as for SigmaPBDE in umbilical cord plasma and house dust. The positive correlations for PBDEs for both maternal and umbilical cord plasma with house dust showed that domestic house dust is a significant source of human exposure to PBDEs in Denmark including in utero exposure.

Developing a biomonitoring educational pamphlet for potential participants in a breast milk biomonitoring study

Over the past decade, biomonitoring research initiatives in the United States have increased because of growing concern over the accumulation of environmental chemicals in the human body. One matrix that has become a viable biological sample for estimating human exposure to environmental chemicals is breast milk. However, breast milk biomonitoring research can induce anxiety and confusion about breastfeeding if communication is lacking between researchers, community partners, and participants. To bridge this communication gap, an informative, reassuring 8-page pamphlet was developed to educate community partners and potential participants about research on 1 class of environmental chemicals-polybrominated diphenyl ethers. Not only did the pamphlet assist in participant recruitment, but it forged positive relationships with valuable community partners.

Prenatal exposure to PBDEs and neurodevelopment

BACKGROUND

Polybrominated diphenyl ethers (PBDEs) are widely used flame retardant compounds that are persistent and bioaccumulative and therefore have become ubiquitous environment contaminants. Animal studies suggest that prenatal PBDE exposure may result in adverse neurodevelopmental effects.

OBJECTIVE

In a longitudinal cohort initiated after 11 September 2001, including 329 mothers who delivered in one of three hospitals in lower Manhattan, New York, we examined prenatal PBDE exposure and neurodevelopment when their children were 12-48 and 72 months of age.

METHODS

We analyzed 210 cord blood specimens for selected PBDE congeners and assessed neurodevelopmental effects in the children at 12-48 and 72 months of age; 118, 117, 114, 104, and 96 children with available cord PBDE measurements were assessed at 12, 24, 36, 48, and 72 months, respectively. We used multivariate regression analyses to evaluate the associations between concentrations of individual PBDE congeners and neurodevelopmental indices.

RESULTS

Median cord blood concentrations of PBDE congeners 47, 99, and 100 were 11.2, 3.2, and 1.4 ng/g lipid, respectively. After adjustment for potential confounders, children with higher concentrations of BDEs 47, 99, or 100 scored lower on tests of mental and physical development at 12-48 and 72 months. Associations were significant for 12-month Psychomotor Development Index (BDE-47), 24-month Mental Development Index (MDI) (BDE-47, 99, and 100), 36-month MDI (BDE-100), 48-month full-scale and verbal IQ (BDE-47, 99, and 100) and performance IQ (BDE-100), and 72-month performance IQ (BDE-100).

CONCLUSIONS

This epidemiologic study demonstrates neurodevelopmental effects in relation to cord blood PBDE concentrations. Confirmation is needed in other longitudinal studies.

Human exposure to polybrominated diphenyl ethers at production area, China

The concentrations of polybrominated diphenyl ethers (PBDEs) were detected in air and aquatic products in PBDEs production areas which are located at the south coast area of Laizhou Bay, Shandong province, China in this study. Concentrations of SigmaPBDEs in the air ranged from 0.47 ng/m3 to 161 ng/m3. In aquatic products, concentrations of SigmaPBDEs ranged from 2.7 ng/g wet weight to 42 ng/g wet weight. The mean dietary intake of SigmaPBDEs via aquatic products consumption in this study was 218 ng/day. Daily intake of SigmaPBDEs via inhalation in this study was 612 ng for men and 455 ng for women. With a contribution of 80%, BDE-209 was predominant in the total intake. Dietary intake and breathing inhalation contributed 29 and 71%, respectively, to the total PBDEs intake. The results indicate that breathing inhalation also plays a very significant pathway for the population of the PBDEs production area. Compared with similar studies in other countries, human exposure to PBDEs via diet and inhalation in this study was the highest in the world.

Indoor contamination with hexabromocyclododecanes, polybrominated diphenyl ethers, and perfluoroalkyl compounds: an important exposure pathway for people?

This review underlines the importance of indoor contamination as a pathway of human exposure to hexabromocyclododecanes (HBCDs), polybrominated diphenyl ethers (PBDEs), and perfluoroalkyl compounds (PFCs). There is ample evidence of substantial contamination of indoor dust with these chemicals and that their concentrations in indoor air exceed substantially those outdoors. Studies examining the relationship between body burden and exposure via indoor dust are inconsistent; while some indicate a link between body burdens and PBDE and HBCD exposure via dust ingestion, others find no correlation. Likewise, while concentrations in indoor dust and human tissues are both highly skewed, this does not necessarily imply causality. Evidence suggests exposure via dust ingestion is higher for toddlers than adults. Research priorities include identifying means of reducing indoor concentrations and indoor monitoring methods that provide the most "biologically-relevant" measures of exposure as well as monitoring a wider range of microenvironment categories. Other gaps include studies to improve understanding of the following: emission rates and mechanisms via which these contaminants migrate from products into indoor air and dust; relationships between indoor exposures and human body burdens; relevant physicochemical properties; the gastrointestinal uptake by humans of these chemicals from indoor dust; and human dust ingestion rates.

Congener-specific body burden levels and possible determinants of polybrominated diphenyl ethers in the general Japanese population

OBJECTIVE

Our objective was to investigate congener-specific body burden levels and possible determinants of polybrominated diphenyl ethers (PBDEs) in the Japanese human population.

METHODS

We conducted a cross-sectional study on 72 participants aged 15-74 years; subjects were not occupationally exposed to PBDEs or dioxin-like polychlorinated biphenyls (DL-PCBs). Participants lived in two urban areas and two fishing villages. Twenty-seven PBDE congeners, PCB-126, PCB-118, PCB-156, and biochemical factors were determined in fasting blood. A questionnaire survey on life-style was also conducted.

RESULTS

More than half of the PBDE values for 14 congeners were below the levels of detection (LODs). The median concentration of total PBDEs was 3.6 ng g(-1) lipid. The most abundant congener was BDE-209 (median concentration, 0.90 ng g(-1) lipid), followed by BDE-153, BDE-207, and BDE-47 in the given order. Most PBDE congeners with < or = 6 bromine atoms had significant positive associations with the concentrations of the three DL-PCBs (suggesting common routes of exposure) and with plasma concentrations of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), biological markers of fish intake. These associations did not change substantially after adjustment for age, sex, and log(body mass index). These positive associations with the concentrations of DL-PCBs or EPA/DHA were not found in analyses of high-brominated PBDE congeners with > or = 8 bromine atoms.

CONCLUSIONS

Fish consumption may be a major contributor to the accumulation of PBDE congeners with 6 bromine atoms among the general Japanese population. In contrast, the main exposure routes to high-brominated PBDEs in humans are probably not associated with fish consumption.

PBDEs in 2-5 year-old children from California and associations with diet and indoor environment

This study determined the body burden of PBDEs in 100 California children, and evaluated associations with sociodemographic, household, and dietary factors. In national and international comparisons, California dust, breast milk, and human serum samples contain higher concentrations of PBDEs. Higher levels in children suggest exposure pathways depend upon age. Plasma samples were analyzed for PBDEs using GC/MS. Circulating levels of PBDEs were 10-to 1000-fold higher than similar aged populations in Mexico and Europe, 5-times higher than similar aged children across the U.S., and 2- to 10-fold higher than U.S. adults. Increased levels of higher-brominated congeners were associated with the recent purchase of new upholstered furniture or mattresses and consumption of pork. Concentrations of lower-brominated congeners increased with frequency of poultry consumption. Lower maternal education was independently and significantly associated with higher levels of most congeners in the children.

Polybrominated diphenyl ethers (PBDEs) and hexabromocyclodecane (HBCD) in composite U.S. food samples

OBJECTIVES

This study was designed to update previous U.S. market basket surveys of levels and polybrominated diphenyl ether (PBDE) dietary intake calculations. This study also quantifies hexabromocyclododecane (HBCD) levels in U.S.-purchased foods for the first time and estimates U.S. dietary intake of HBCD. This is part of a larger market basket study reported in two companion articles, of current levels of certain persistent organic pollutants (POPs) PBDEs, HBCD, perfluorinated compounds, polychlorinated biphenyls, and pesticides in composite food samples collected in 2008-2009.

METHODS

In this study, we measured concentrations of 24 PBDE congeners and total HBCD in composite samples of 31 food types (310 samples). U.S. dietary intake of PBDEs and HBCD was estimated referencing the most current U.S. Department of Agriculture loss-adjusted food availability report.

RESULTS

Total PBDE concentrations in food varied by food type, ranging from 12 pg/g wet weight (ww) in whole milk to 1,545 pg/g ww in canned sardines and 6,211 pg/g ww in butter. Total HBCD concentrations also varied substantially within and among food groups, ranging from 23 pg/g in canned beef chili to 593 pg/g in canned sardines. HBCD was not detected in any dairy samples. Dietary intake of all PBDE congeners measured was estimated to be 50 ng/day, mostly from dairy consumption but also from meat and fish. HBCD intake was estimated at 16 ng/day, primarily from meat consumption.

CONCLUSION

PBDEs and HBCDs currently contaminate some food purchased in the United States, although PBDE intake estimated in this study is lower than reported in our previous market basket surveys. HBCD is in food at higher levels than expected based on previously reported levels in milk and blood compared with PBDE levels and is comparable to European levels.

Polybrominated diphenyl ethers (PBDEs) contents in house and car dust of Portugal by pressurized liquid extraction (PLE) and gas chromatography-mass spectrometry (GC-MS)

Dust is the repository of various compounds including flame retardants. In this study an analytical method based on PLE extraction and gas chromatography-mass spectrometry was selected for the analysis of 16 PBDEs congeners in house and car dust samples collected in Portugal. The analytical performance of the method was validated using standard reference material (SRM); values from 90% to 109% and from 2% to 11% were obtained for recovery and precision, respectively. The PBDE congeners distribution in whole and sieved fractions of the dust samples, as well as influence of the source on the levels of these contaminants, were obtained. The wide range of PBDEs contents found in the dust samples indicates heterogeneous levels of contamination in these matrices. The clearest feature of the results obtained was that Deca-BDE was the main PBDE in both house and car dust samples. The total PBDEs measured in house dust (ranging from 34 to 1928 ng g(-1)) was lower than those found in car dust (ranging from 193 to 22955 ng g(-1)). However, house dust provides a major contribution to human exposure due to the time spent there, much higher than in cars.

Levels and patterns of polybrominated diphenyl ethers in children's plasma from Dalian, China

Polybrominated diphenyl ethers (PBDEs) are potential persistent organic pollutants which have raised many concerns in recent years. Research focusing on children exposure to PBDEs is important but insufficient. The levels and patterns of PBDEs in children's plasma from Dalian, China were studied for the first time. Seventeen PBDE congeners (BDE-30, 28, 35, 37, 75, 47, 66, 100, 99, 116, 155, 154, 153, 183, 181, 190 and 209) in 29 plasma samples were measured. Median PBDE concentration was 31.61 ng g(-1) lipid. BDE-153 was the dominant congener, followed by BDE-99, 47, and 183. High abundance of BDE-183 suggested a higher Octa-BDE use in China. No significant differences were observed between males and females or among different age groups. The levels of PBDEs in children's plasma in the present study were 9-30 times higher than those in non-occupational exposure people from Guangzhou, South China and those in human milk of general adults from other cities of China, but were at the moderate levels of those in children around the world. These results indicate that children in Dalian are at a high risk of exposure to PBDEs.

PBDEs in indoor dust in South-Central China: characteristics and implications

Dust samples were collected randomly from 76 houses, 12 offices, 43 outdoor sites, two televisions and two computers in South-Central China. The indoor dust samples were analyzed for the concentrations, congener profiles, and possible sources of polybrominated diphenyl ethers (PBDEs) and compared to similar data obtained for outdoor dusts. The concentrations of Sigma(10)PBDEs (the sum of BDE28, 47, 66, 85, 99, 100, 153, 154, 183, and 209) were 186.6-9654 ng g(-1) (mean=2662 ng g(-1)) and 1737-4408 ng g(-1) (mean=3179 ng g(-1)) for house dust and office dust, respectively. No significant differences were found among the congener profiles of PBDEs in house dust from three different cities. The dominant congener in all dust samples was BDE209, accounting for an average of 96.2%, 99.0% and 97.4% of Sigma(10)PBDEs for house dust, office dust and outdoor dust, respectively. Unlike previous studies, this study found that BDE183 was present in high proportion to Sigma(9)PBDEs (BDE209 excluded) in both indoor and outdoor dusts, in addition to the usually dominant congeners, BDE47 and 99. Sigma(10)PBDEs concentrations in house dust were higher than those in outdoor dust for most comparison samples. Combined with the significantly higher Sigma(10)PBDEs concentrations in television and computer dusts, PBDE-containing products used indoors, including television and computers, were important potential emission sources for PBDEs in indoor dusts. Further studies are required to detail the source of the high levels of BDE183 in Chinese indoor dusts.

Individual characteristics associated with PBDE levels in U.S. human milk samples

BACKGROUND

Reported polybrominated diphenyl ether (PBDE) concentrations in human samples in the United States have been higher than in Europe and Asia. Little is known about factors that contribute to individual variability in body burden.

OBJECTIVE

In this large study we measured PBDE concentrations in human milk from the United States during 2004-2006. We assessed characteristics associated with concentrations in milk and change in milk concentration between 3 and 12 months postpartum.

METHODS

We analyzed 303 milk samples obtained 3 months postpartum for PBDEs. A second sample was analyzed for 83 women still lactating 12 months postpartum. PBDE concentrations in milk and variability by individual characteristics such as age, parity, and prepregnancy body mass index (BMI) were evaluated using generalized linear models.

RESULTS

PBDE congeners BDEs 28, 47, 99, 100, and 153 were detected in > 70% of samples. BDE-47 concentrations were the highest, ranging from below the limit of detection to 1,430 ng/g lipid, with a median of 28 ng/g lipid. Concentrations of most individual PBDE congeners and the sum of BDEs 28, 47, 99, 100, and 153 (SigmaPBDE) were lower among mothers > 34 years of age compared with those 25-29 years of age and higher among mothers with high compared with normal BMI, after adjustment for other covariates. Parity was not associated with PBDE concentration. The change in SigmaPBDE concentration in milk between 3 and 12 months postpartum was highly variable (median increase, 14%; interquartile range, -26% to 50%).

CONCLUSIONS

PBDEs were detected in nearly all human milk samples, varying by maternal weight and age and over the course of breast-feeding.

Determinants of brominated flame retardants in breast milk from a large scale Norwegian study

Brominated flame retardants (BFRs), particularly polybrominated diphenyl ethers (PBDEs), are widely present in human populations. In order to investigate human exposure pathways and associations with socioeconomic and lifestyle factors, 393 breast milk samples from mothers living in various regions throughout Norway were analyzed. Up to ten PBDE congeners were measured in all the samples, hexabromocyclododecane (HBCD) and BDE-209 in subsets of 310 and 46, respectively. The median concentrations of the sum of the seven most prominent PBDEs (BDE-28, 47, 99, 100, 153, 154 and 183), BDE-209 and HBCD were 2.1, 0.32 and 0.86ng/g lipids, respectively. These concentrations are comparable to the levels generally observed in human populations in Europe. The frequency distributions were quite skewed with long tails towards higher concentrations. Maternal age, parity, education, having a cohabitant employed as electrician, and ventilation were factors significantly associated with some of the BFRs, although these factors only explained a small amount of the variability (R(2) 0.04-0.16). The mothers' diet was not found to influence the breast milk PBDE and HBCD levels. Our results show that sources other than the diet are important for the variability seen in breast milk BFR concentrations and that exposure from the indoor atmosphere should be emphasized in future studies.

Household exposures to polybrominated diphenyl ethers (PBDEs) in a Wisconsin Cohort

BACKGROUND

Human exposure to polybrominated diphenyl ethers (PBDEs) is virtually universal in the United States. Although the uses of these chemicals as flame retardants in fabrics, foams, and plastics are well defined, human exposure pathways are not well understood.

OBJECTIVES

This study was designed to assess current PBDE body burdens and identify residential sources of exposure among 29 men and 15 women in 38 households.

METHODS

Portable X-ray fluorescence (XRF) analyzers were used to measure bromine levels in upholstered furnishings, bedding, vehicle interiors, and electronic devices. Vacuum cleaner contents, indoor air samples, and blood sera were analyzed for PBDE congeners using conventional gas chromatograph methods.

RESULTS

Bromine levels varied widely within similar household items. The greatest range for upholstered items was found among vehicle seat cushions (7-30,600 ppm). For electronic devices, television sets ranged from 4 ppm to 128,300 ppm. Based on mixed effects modeling, adjusting for couple households, the bromine content in the participants' sleeping pillows and primary vehicle seat cushions were the strongest predictors of log lipid-adjusted blood serum PBDE concentrations (p-values = 0.005 and 0.03, respectively). The total pentaBDE congener levels found in dust samples and in passive air samples were not significant predictors of blood sera levels.

CONCLUSIONS

This study demonstrates the usefulness of the portable XRF analyzer in identifying household items that may contribute to human exposure to PBDEs.

Particle size fractionation and human exposure of polybrominated diphenyl ethers in indoor dust from Chicago

The objective of this study was to investigate the concentration level, the mass distribution based on dust particle size, and the associated human exposure of polybrominated diphenyl ethers (PBDEs) in indoor dust. The total concentration of 13 PBDEs Sigma(13)(BDEs) was found to be 500-6,944 ng/g in indoor dusts, 4,000 ng/g in car interior dust, 260-300 ng/g in outdoor ambient air particles, 30 ng/g in carpet fibers, and as high as 0.5% in carpet padding. Selected dust samples were fractionated based on particle size, and over 80% of the Sigma(13)BDEs were associated with particles < 150 mum in diameter. Mass ratios of BDE206/BDE209 are higher in both indoor and outdoor samples than in commercial deca products; and mass ratio BDE47/BDEs(85+99+100) was much higher in outdoor than in indoor samples. Using EPA software ProUCL, the exposure of Americans to PBDEs via hand-to-mouth transfer of house dust was estimated under the central tendency exposure and reasonable maximum exposure scenarios. The results suggest that ingestion of PBDE-laden house dust via hand-to-mouth contact is likely a significant exposure pathway, especially for children.

Exposure to hexabromocyclododecanes (HBCDs) via dust ingestion, but not diet, correlates with concentrations in human serum: preliminary results

BACKGROUND

Hexabromocyclododecane (HBCD) is a high-production-volume chemical used as flame retardant in polystyrene insulation and textiles. Because it is not chemically bound to the polymer, HBCD can migrate into the environment, contaminating indoor dust and foodstuff.

OBJECTIVES

We examined for the first time the relationship between combined exposure to three HBCD isomers (SigmaHBCDs) via ingestion of food (duplicate diets) and indoor dust and HBCD concentrations in serum for 16 Belgian adults (20-25 years of age). We also determined the chiral signatures of HBCDs to advance understanding of source-to-human enantioselective degradation and/or metabolism.

METHODS

Concentrations and chiral signatures of alpha-, beta-, and gamma-HBCD in duplicate diets, dust, and serum were measured by liquid chromatography/tandem mass spectrometry.

RESULTS

Dietary intakes of SigmaHBCDs were 1.2-20 ng/day (average, 7.2 ng/day), whereas those estimated under average (20 mg dust/day) and high (50 mg dust/day) dust ingestion scenarios were 1.1-15 ng/day (average intake, 3.2 ng/day) and 2.8-38 ng/day (average intake, 8.0 ng/day), respectively. Concentrations of SigmaHBCDs measured in blood serum were < 0.5 to 11 ng/g lipid weight (lw) (average, 2.9 ng/g lw). Gamma-HBCD dominated in food, whereas alpha-HBCD dominated in dust and was the sole isomer in serum. Although exposure via dust ingestion correlated significantly (p < 0.01) with concentrations in serum, no such correlation was evident with dietary exposure (p > 0.1). Although no enantioselective enrichment was detected in either dust or diet, substantial enrichment of (-)alpha-HBCD was observed in serum.

CONCLUSIONS

Serum concentrations of HBCDs were correlated with the exposure via dust, but not via dietary ingestion. The enrichment of the (-)alpha-HBCD enantiomer in humans appears to be due to in vivo enantioselective metabolism/excretion rather than ingestion of dust or diet.

Polybrominated diphenyl ethers cause oxidative stress in human umbilical vein endothelial cells

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants to prevent combustion in consumer products, such as electronics, construction materials, and textiles and, therefore, have become important commercial substances. PBDEs were also detected in maternal blood, breast milk, umbilical cord blood, and cord tissue, thereby indicating that fetuses were also exposed to PBDEs. The purpose of this study is to identify the effect of PBDEs on human umbilical vein endothelial cells (HUVECs). Cultured HUVECs were exposed to a commercial mixture of penta-BDE (DE71), octa-BDE (DE79), and deca-BDE (DE83). Each gene expression that was altered in DNA microarray was confirmed by real-time reverse transcription-polymerase chain reaction and Western blotting analysis. The results indicated that gene expressions concerning antioxidant system, i.e., thioredoxin family, 24-dehydrocholesterol reductase (DHCR24), and tumor suppressor protein p53, were altered by PBDEs exposure in HUVECs. Moreover, it was demonstrated that thioredoxin-interacting protein (TXNIP) was a target gene in exposure to DE71 and DE79 in HUVECs, by drastically decreasing time-dependent TXNIP expression in HUVECs.

A newly recognized occupational hazard for US electronic recycling facility workers: polybrominated diphenyl ethers

OBJECTIVE

To describe a newly recognized US occupational health hazard, polybrominated diphenyl ether (PBDE) flame retardant exposure, to US workers at electronics recycling facilities to communicate this information to occupational medicine physicians and related health workers.

METHODS

Using PBDE air values reported from a California electronic recycling facility and estimates of US food, air and dust intake, electronic recycling facility workers' PBDE exposure at this facility was estimated using multiple possible scenarios. We compared these estimates to intake estimates for the US general population. Occupational PBDE study findings from China, Sweden, and Norway where elevated environmental or blood PBDE levels were detected in similar workers are reviewed.

RESULTS

An approximate 6-fold to 33-fold increase in the electronic recycling facility workers' PBDE exposure was estimated compared with the US general population.

CONCLUSION

PBDE exposure in US electronic recycling facilities is a largely unrecognized occupational health hazard. The extent of worker exposure in the US should be better characterized and steps taken to lower levels of PBDEs in the workplace where exposure exists. Health care providers, plant safety professionals, and government agencies can play a role in recognizing the problem and in decreasing worker exposure.

Levels and regional trends of persistent organochlorines and polybrominated diphenyl ethers in Asian breast milk demonstrate POPs signatures unique to individual countries

Human breast milk samples collected in 2007-2008 from four countries, Vietnam (Hanoi), China (Beijing), Korea (Seoul) and Japan (Sendai, Kyoto and Takayama), were analyzed for persistent organic pollutants (POPs) such as dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlordane-related compounds (CHLs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). Comparing with previous surveys, the present study indicates that the DDTs in breast milk from China and Vietnam had gradually decreased during the last decade, but were still 5-10 times higher than those in other nations. The ratios of p,p'-DDE/p,p'-DDT and o,p'-DDT/p,p'-DDT were higher in Beijing than in the other countries, suggesting that there is less fresh intake of commercial DDT products and a possible exposure to dicofol in China. CHL and PCB levels were relatively higher in mothers from Japan, whereas beta-HCH and HCB were more common in Chinese women. In Japan, it is suspected that mothers in the urban/coastal area (Sendai) were more continuously exposed to organochlorine pesticides (OCPs) than mothers in the rural/inland area (Takayama). In addition, OCP levels in primiparae were significantly higher than those in multiparae from Japan and Korea. These indicate that both parity and regional factors are major determinants of the levels of OCPs and PCBs in human milk. On the other hand, higher concentrations of PBDEs were observed in mothers' milk from Korea. The congener was dominated by BDE-47 (43-54%), followed by BDE-153 (23-33%) in all regions except for Beijing where BDE-28 (23%) was relatively abundant. In Japanese breast milk, regional and parity-dependent distributions were not observed for PBDEs. Among PBDE congeners, age-dependency was observed for BDE-153, which was negatively correlated (p<0.05) to the age of mothers in Kyoto (17 participants were housewives), while it increased with age in Sendai (10 participants were clerks). No such correlation was seen for BDE-47, indicating that BDE-47 was ingested and assimilated via different kinetics or routes from BDE-153 in Japan.

Diet contributes significantly to the body burden of PBDEs in the general U.S. population

BACKGROUND

Exposure of the U.S. population to polybrominated diphenyl ethers (PBDEs) is thought to be via exposure to dust and diet. However, little work has been done to empirically link body burdens of these compounds to either route of exposure.

OBJECTIVES

The primary goal of this research was to evaluate the dietary contribution to PBDE body burdens in the United States by linking serum levels to food intake.

METHODS

We used two dietary instruments--a 24-hr food recall (24FR) and a 1-year food frequency questionnaire (FFQ)--to examine food intake among participants of the 2003-2004 National Health and Nutrition Examination Survey. We regressed serum concentrations of five PBDEs (BDE congeners 28, 47, 99, 100, and 153) and their sum (Sigma PBDE) against diet variables while adjusting for age, sex, race/ethnicity, income, and body mass index.

RESULTS

Sigma PBDE serum concentrations among vegetarians were 23% (p = 0.006) and 27% (p = 0.009) lower than among omnivores for 24FR and 1-year FFQ, respectively. Serum levels of five PBDE congeners were associated with consumption of poultry fat: Low, medium, and high intake corresponded to geometric mean Sigma PBDE concentrations of 40.6, 41.9, and 48.3 ng/g lipid, respectively (p = 0.0005). We observed similar trends for red meat fat, which were statistically significant for BDE-100 and BDE-153. No association was observed between serum PBDEs and consumption of dairy or fish. Results were similar for both dietary instruments but were more robust using 24FR.

CONCLUSIONS

Intake of contaminated poultry and red meat contributes significantly to PBDE body burdens in the United States.

Detection of organophosphate flame retardants in furniture foam and U.S. house dust

Restrictions on the use of polybrominated diphenyl ethers (PBDEs) have resulted in the increased use of alternate flame retardant chemicals to meet flammability standards. However, it has been difficult to determine which chemical formulations are currently being used in high volumes to meet flammability standards since the use of flame retardant formulations in consumer products is not transparent (i.e., not provided to customers). To investigate chemicals being used as replacements for PentaBDE in polyurethane foam, we analyzed foam samples from 26 different pieces of furniture purchased in the United States primarily between 2003 and 2009. Samples included foam from couches, chairs, mattress pads, pillows, and, in one case, foam from a sound-proofing system of a laboratory-grade dust sieve, and were analyzed using gas chromatography mass spectrometry. Fifteen of the foam samples contained the flame retardanttris(1,3-dichloro-2-propyl) phosphate (TDCPP; 1-5% by weight), four samples contained tris(1-chloro-2-propyl) phosphate (TCPP; 0.5 -22% by weight), one sample contained brominated chemicals found in a new flame retardant mixture called Firemaster 550 (4.2% by weight), and one foam sample collected from a futon likely purchased prior to 2004 contained PentaBDE (0.5% by weight). Due to the high frequency of detection of the chlorinated phosphate compounds in furniture foam,we analyzed extracts from 50 house dust samples collected between 2002 and 2007 in the Boston, MA area for TDCPP, TCPP, and another high volume use organophosphate-based flame retardant used in foam, triphenylphosphate (TPP). Detection frequencies for TDCPP and TPP in the dust samples were > 96% and were log normally distributed, similar to observations for PBDEs. TCPP was positively detected in dust in only 24% of the samples, but detection was significantly limited by a coelution problem. The geometric mean concentrations for TCPP, TDCPP, and TPP in house dust were 570, 1890, and 7360 ng/g, respectively, and maximum values detected in dust were 5490, 56,080 and 1,798,000 ng/g, respectively. These data suggest that levels of these organophosphate flame retardants are comparable, or in some cases greater than, levels of PBDEs in house dust. The high prevalence of these chemicals in foam and the high concentrations measured in dust (as high as 1.8 mg/g) warrant further studies to evaluate potential health effects from dust exposure, particularly for children.

Patterns and concentration levels of polybrominated diphenyl ethers (PBDEs) in placental tissue of women in Denmark

The levels and congener patterns of PBDEs were investigated in human placental samples in Denmark. The median concentrations of sigmaPBDE(tri-hepta) and BDE-209 in the 50 samples were 1.22 and 1.14 ng g(-1) lw, respectively, with the total sum ranging from 0.51 to 17.1 ng g(-1) lw, which is similar to previous placental studies. The PBDE content in placental tissue was dominated by BDE-209, which accounted for approximately 50% of the total amount of PBDEs. BDE-47, -99, and -153 were detected in all samples. Approximately equal amounts of BDE-47 and BDE-153 were observed in the placental tissue, which is in agreement with previous European studies of human serum. Principal Component Analysis (PCA) was performed to analyze congener patterns within and between mothers. The loading plot showed groupings of the measured PBDE variables in three groups, representative of Penta-, Octa- and Deca-BDE technical mixtures. Congeners representing the individual technical mixtures were close to orthogonal or inversely correlated, indicating variation in the congener patterns of internal exposure corresponding to the patterns of technical mixtures used in products. Visualisation of the participant objects according to body mass index (BMI), revealed inherent congener patterns (19% X-variance) showing increased frequency for participants within the highest BMI group to have elevated concentrations of BDE-209 in the placental tissue.

Composition, distribution, and characterization of polybrominated diphenyl ethers in sandstorm depositions in Beijing, China

This study was conducted to determine the concentration of 8 polybrominated diphenyl ethers (PBDEs) in sandstorm depositions in Beijing, China. The PBDE concentrations in 10 samples collected in Beijing ranged from 8.47 to 29.02 ng g(-1), with BDE-209 as the predominant congener (>85%). Principal component analysis revealed that the major source of PBDEs in Beijing may be potentially associated with deca-BDE. Furthermore, increasing PBDE contamination was observed from northwest to east Beijing. Finally, possible factors affecting contamination of the sandstorm depositions were subsequently explored revealing a significant correlation between SigmaPBDEs and the minimum particle size of the sandstorm deposition samples.

Brominated flame retardants in Belgian home-produced eggs: levels and contamination sources

The extent and the sources of contamination with brominated flame retardants (BFRs), such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD), in home-produced eggs from free-foraging chicken of Belgian private owners were investigated. Various factors, such as seasonal variability, exposure of chickens through diet (kitchen waste) and soil, and elimination of BFRs through eggs and faeces were assessed. PBDEs were more important than HBCD in terms of concentrations and detection frequency. Concentrations of PBDEs and HBCD in Belgian home-produced eggs were relatively low and comparable with reported levels from other European countries and the US. The concentrations of PBDEs (sum of 13 congeners, including BDE 209) ranged between not detected and 32 ng/g lipid weight (lw), with medians of 3.0 and <2.0 ng/g lw for the autumn 2006 and spring 2007 campaigns, respectively. When present, BDE 209 was the major PBDE congener (45% of sum PBDEs). When BDE 209 was not detected, the PBDE profile was composed of PentaBDE (BDE 99 and BDE 47), with, in some cases, higher contribution of OctaBDE (BDE 183 and BDE 153). HBCD was also detected (<0.4 and 2.9 ng/g lw for the autumn 2006 and spring 2007 campaigns, respectively), but at lower detection frequency. The highest HBCD value was 62 ng/g lw. The similarity between profiles and seasonal variations in the concentrations of BFRs in soil and eggs indicate that soil is an important source, but not the sole source, for eggs laid by free-foraging chicken. The contamination of eggs with PBDEs and HBCD appears to be of low concern for public health and the contribution of eggs to the total daily intake of PBDEs appears to be limited (10% for chicken owners and 5% for the average Belgian consumer).

An assessment of sources and pathways of human exposure to polybrominated diphenyl ethers in the United States

Polybrominated diphenyl ethers (PBDEs) are ubiquitous in the indoor environment, owing to their use in consumer products ranging from electronics to mattresses, furniture, and carpets. People are exposed to PBDEs through inhalation of indoor air and ingestion, and dermal absorption of dust particles present in the air. In this study, concentrations of PBDEs were determined in indoor air and house dust collected from homes in Albany, New York, USA. Based on the measured concentrations of PBDEs in indoor air and dust, we estimated daily exposure dose (DED) of PBDEs. In addition, we used previously published PBDE concentrations reported for breast milk from Massachusetts, USA [Johnson-Restrepo, B., Addink, R., Wong, C., Arcaro, K., Kannan, K., 2007. Polybrominated diphenyl ethers and organochlorine pesticides in human breast milk from Massachusetts. USA. J. Environ. Monitor. 9, 1205-1212] and foodstuffs collected from Texas and Florida, USA [Schecter, A., Päpke, O., Harris, T.R., Tung, K.C., Musumba, A., Olson, J., Birnbaum, L., 2006. Polybrominated diphenyl ether (PBDE) levels in an expanded market basket survey of U.S. food and estimated PBDE dietary intake by age and sex. Environ. Health Perspect. 114, 1515-1520, Johnson-Restrepo, B., Kannan, K., Addink, R., Adams, D.H., 2005b. Polybrominated diphenyl ethers and polychlorinated biphenyls in a marine foodweb of coastal Florida. Environ. Sci. Technol. 39, 8243-8250], in an estimation of dietary exposure to PBDEs. The exposure assessment was performed for five age groups: infants (<1yr), toddlers (1-5yr), children (6-11yr), teenagers (12-19yr), and adults (20yr). The dust ingestion and air inhalation factors that we used were the US Environmental Protection Agency's (EPA) exposure factors, while the daily food intake rates (g/day) were derived from the US Department of Agriculture's (USDA) food intake surveys. The total DED of PBDEs was calculated by summation of the exposures from diet, indoor air, and house dust. The average estimated DED of PBDEs was the highest for breastfed infants (86.4ng/kg-bw/day), contributed primarily (91%) from the consumption of breast milk. The average DED of PBDEs for toddlers, children, teenagers, and adults was respectively, 13.3, 5.3, 3.5, and 2.9ng/kg-bw/day. Ingestion and dermal absorption of house dust are the major pathways of PBDE exposure in toddlers, children, teenagers, and adults accounting for, on average, 56-77% of the total PBDE intake.

Polybrominated diphenyl ethers in marine ecosystems of the American continents: foresight from current knowledge

Polybrominated diphenyl ethers (PBDEs) are a class of synthetic halogenated organic compounds used in commercial and household products, such as textiles, furniture, and electronics, to increase their flame ignition resistance and to meet fire safety standards. The demonstrated persistence, bioaccumulation, and toxic potential of these compounds in animals and in humans are of increasing concern. The oceans are considered global sinks for PBDEs, as higher levels are found in marine organisms than in terrestrial biota. For the past three decades, North America has dominated the world market demand for PBDEs, consuming 95% of the penta-BDE formulation. Accordingly, the PBDE concentrations in marine biota and people from North America are the highest in the world and are increasing. Despite recent restrictions on penta- and octa-BDE commercial formulations, penta-BDE containing products will remain a reservoir for PBDE release for years to come, and the deca-BDE formulation is still in high-volume use. In this paper, we review all available data on the occurrence and trends of PBDEs in the marine ecosystems (air, water, sediments, invertebrates, fish, seabirds, and marine mammals) of North and South America. We outline here our concerns about the potential future impacts of large existing stores of banned PBDEs in consumer products, and the vast and growing reservoirs of deca-BDE as well as new and naturally occurring brominated compounds on marine ecosystems.

Determinants of plasma concentrations of perfluorooctanesulfonate and brominated organic compounds in Nunavik Inuit adults (Canada)

Perfluorooctanesulfonate (PFOS) and brominated organic compounds (BOCs) have been found in biota and humans worldwide with levels of BOCs being the highest in North America. PFOS and BOC exposure of remote populations that consume species of a marine food web for their subsistence has seldom been investigated. In 2004, we determined the concentrations of these contaminants in 883 Nunavik Inuit adults from the Canadian Arctic and investigated the demographic and dietary factors associated with them. Demographic and dietary information were collected by questionnaires. Multiple linear regressions were conducted to investigate predictors of exposure to those contaminants. Polychlorinated biphenyl (PCB) congener 153 concentrations are presented for comparative purposes. PFOS and PCB 153 were detected in all samples, with plasma concentrations several times higher than BOCs. The consumption of fish and marine mammals appears to be an important contributor to PFOS exposure among Nunavik Inuit. While PBDE 153 also appears as a persistent PBDE congener, exposure to PBDE 47 seems to be more recent in this population. Adoption of a westernized lifestyle seems to be related to an increased exposure to PBDE 47, but specific sources remain to be elucidated. In conclusion, we found that the remote geographical location and traditional lifestyle of the Nunavik Inuit population do not protect them against exposure to emerging POPs, particularly PFOS.

Brominated flame retardants and other polyhalogenated compounds in indoor air and dust from two houses in Japan

This study analyzed polyhalogenated compounds (PHCs) such as brominated flame retardants (BFRs) in indoor air and dust samples from two modern homes in Japan. Concentrations of polychlorinated biphenyls (PCBs) and 2,4,6-tribromophenol (2,4,6-TBP) in exhaust and indoor air of two houses were detected at 10(2)-10(3)pgm(-3) order, which were well above those in outdoor air. For dust samples, the detected polybrominated diphenyl ether (PBDE) and polybrominated dibenzo-p-dioxins/furan concentrations resembled values found in our past study. Interestingly, compared to PBDE concentrations, two orders of magnitude higher concentration (13000 ng g(-1)) was observed for hexabromocyclododecanes (HBCDs) in a dust sample from one house. Based on the calculation of air/dust partition ratio values (Kad), low Kad values (log Kad <or=0) were obtained for high brominated PBDEs (pentaBDEs - decaBDE), tetrabromobisphenol A (TBBPA), and HBCDs, although indoor air contained higher contents of low chlorinated PCBs, low brominated PBDEs, and 2,4,6-TBP. Attention should be given to exposure to 2,4,6-TBP through inhalation of air as well as dust ingestion. Results of X-ray fluorescence analysis show high bromine concentrations in curtain and roll screen samples possessing a high product loading factor. Furthermore, a preliminary estimation was made of the likely magnitude of inhabitants' exposure to PHCs via inhalation and dust ingestion in the two houses.

Versatility of a new bioinorganic catalyst: palladized cells of Desulfovibrio desulfuricans and application to dehalogenation of flame retardant materials

The versatility and reaction specificity of a novel bioinorganic catalyst is demonstrated in various reactions. Palladized cells (bioPd) of the sulphate-reducing bacterium Desulfovibrio desulfuricans showed an increased product selectivity and a catalytic activity comparable to a commercial Pd catalyst in several industrially relevant hydrogenations and hydrogenolyses (reductive dehalogenations). The ability of palladized cells to promote the reductive debromination of a polybrominated diphenyl ether (PBDE #47) is demonstrated, although chemically reduced Pd(II) and commercial Pd(0) were more effective debromination agents. Polybrominated diphenyl ethers are being supplanted as flame retardants by other compounds, e.g. tris(chloroisopropyl)phosphate (TCPP), the concentration of which was seen to increase approximately 10-fold in groundwater samples between 2000 and 2004. BioPd dechlorinated TCPP in groundwater samples with >90% recovery of free chloride ion, and was five times more effective than using commercial Pd(0) catalyst. Examination of the spent groundwater using 31P NMR showed a phosphorus species novel to the bioPd-treated solution, which was not evident in a commercial reference sample of TCPP.

Organohalogen compounds in human breast milk from mothers living in Payatas and Malate, the Philippines: levels, accumulation kinetics and infant health risk

Human breast milk samples (n=33) from primipara and multipara mothers from Payatas a waste dump site, and Malate a reference site in the Phillipines were collected in 2004 and analyzed for eight organohalogen compounds, viz., PCBs, DDTs, CHLs, HCHs, HCB, TCPMe, PBDEs and HBCDs. DDTs and PCBs were predominant in all the samples. Overall mean concentrations of PBDEs found in our study were higher (7.5 ng/g lipid wt.) than those reported for Japan and many other Asian countries. Primipara mothers had significantly higher levels of DDTs, CHLs and HCHs than multipara mothers, but not PBDEs and HBCDs. A few individuals accumulated CHLs close to or even higher than the tolerable daily intake guidelines proposed by Health Canada.

Factors influencing concentrations of polybrominated diphenyl ethers (PBDEs) in students from Antwerp, Belgium

Human exposure to polybrominated diphenyl ethers (PBDEs) through food and indoor dust ingestion was assessed for 19 Belgian adults. The intake of PBDEs (sigma-hepta BDEs and BDE 209) in the studied population is influenced mainly by diet Dietary intakes of sigmatri-hepta BDEs (BDEs 28, 47, 99, 100, 153, 154, and 183) were 5.9-22.0 ng/day (median 10.3), while those via dust ingestion were 0.1-1.4 ng/day (median 0.25) or 0.3-3.5 ng/day (average 0.6), assuming dust ingestion rates of 20 and 50 mg/day, respectively. Dietary intakes of BDE 209 were 50-238 ng/day (median 95), whereasthose via dust ingestion were 0.4-11 ng/day (median 1.8) or 1.0-29 ng/day (median 4.6) for dust ingestion rates of 20 and 50 mg/day, respectively. It is important to acknowledge the uncertainty associated with the dust ingestion rates. Concentrations of sigmatri-hepta BDEs measured in blood serum were 0.9-7.2 ng/g lipid weight (lw) (median 1.9). This is similar to other European populations, but lower than for nonoccupationally exposed Americans (average of 19 ng/g lw). When compared with estimates of exposure via both dietary and indoor dust ingestion for Americans, the exposures reported here are consistent with the hypothesis that the difference between European and American body burdens of PBDEs is attributable primarily to greater exposure via dust ingestion for Americans. The total intake of PBDEs through food and dustfor each participant could not be correlated with the corresponding serum concentration. Instead, it is hypothesized that past and episodic current higher intakes of PBDEs are more important determinants of body burden than continuous background exposures at the low levels measured in this study.

Flame retardants in indoor dust and air of a hotel in Japan

Occurrence of flame retardants (FRs) in the indoor environment of highly flame-retarded public facilities is an important concern from the viewpoint of exposure because it is likely that FRs are used to a greater degree in these facilities than in homes. For this study, brominated flame-retardants (BFRs) and organophosphate flame-retardants and plasticizers (OPs), and brominated dibenzo-p-dioxins/furans (PBDD/DFs) were measured in eight floor dust samples taken from a Japanese commercial hotel that was assumed to have many flame-retardant materials. Concentrations of polybrominated diphenylethers (PBDEs) and hexabromocyclododecanes (HBCDs) varied by about two orders of magnitude, from 9.8-1700 ng/g (median of 1200 ng/g) and from 72-1300 ng/g (median of 740 ng/g), respectively. Concentrations of the two types of BFRs described above were most dominant among the investigated BFRs in the dust samples. It is inferred that BFR and PBDD/DF concentrations are on the same level as those in house and office dust samples reported based on past studies. Regarding concentrations of 11 OPs, 7 OPs were detected on the order of micrograms per gram, which are equivalent to or exceed the BFR concentrations such as PBDEs and HBCDs. Concentrations of the investigated compounds were not uniform among dust samples collected throughout the hotel: concentrations differed among floors, suggesting that localization of source products is associated with FR concentrations in dust. Passive air sampling was also conducted to monitor BFRs in the indoor air of hotel rooms: the performance of an air cleaner placed in the room was evaluated in terms of reducing airborne BFR concentrations. Monitoring results suggest that operation of an appropriate air cleaner can reduce both gaseous and particulate BFRs in indoor air.

Polybrominated diphenyl ether (PBDE) concentrations in house dust are related to hormone levels in men

Despite documented widespread human exposure to polybrominated diphenyl ethers (PBDEs) through dietary intake and contact with or inhalation of indoor dust, along with growing laboratory evidence for altered endocrine function following exposure, human studies of PBDE exposure and endocrine effects remain limited. We conducted a preliminary study within an ongoing study on the impact of environmental exposures on male reproductive health. We measured serum hormone levels and PBDE concentrations (BDE 47, 99 and 100) in house dust from 24 men recruited through a US infertility clinic. BDE 47 and 99 were detected in 100% of dust samples, and BDE 100 was detected in 67% of dust samples, at concentrations similar to those reported in previous US studies. In multivariable regression models adjusted for age and BMI, there was a statistically significant inverse relationship between dust PBDE concentrations and free androgen index. Dust PBDE concentrations were also strongly and inversely associated with luteinizing hormone (LH) and follicle stimulating hormone (FSH), and positively associated with inhibin B and sex hormone binding globulin (SHBG). Finally, consistent with limited recent human studies of adults, PBDEs were positively associated with free T4. In conclusion, the present study provides compelling evidence of altered hormone levels in relation to PBDE exposures estimated as concentrations in house dust, and that house dust is an important source of human PBDE exposure, but more research is urgently needed.

PBDEs in US and German clothes dryer lint: a potential source of indoor contamination and exposure

Polybrominated diphenyl ethers (PBDEs) are emerging persistent organic pollutants (POPs). Since the 1970s, PBDEs have been widely used as additive flame retardants in furniture and electronic equipment. Due to their wide use and persistent nature, these chemicals are found in the environment, human blood, breast milk and other tissues in increasing levels in recent decades. PBDEs are similar to polychlorinated biphenyls (PCBs) in structure and toxicity. However, unlike PCBs and PCDDs/PCDFs, the route of PBDE exposure is not almost exclusively through food. PBDE levels in US food are not markedly higher than in Europe, although US human blood and milk levels are an order of magnitude higher. For these reasons, other possible routes of PBDE exposure have been investigated to understand PBDE intake into humans. PBDE contaminated clothes dryer lint and household dust are indicators of indoor contamination and may be sources of human exposure through hand-to-mouth contact or dermal absorption. There are very few publications about PBDEs in US or European lint. Household dryer lint from 12 US and seven German homes were analyzed for PBDEs by gas chromatography coupled to high-resolution mass spectrometry. We found the median US total PBDE levels were more than 10 times higher than median German levels and the mean US levels were two times higher than mean German levels. The US levels ranged from 321 to 3073ngg(-1) (median: 803ngg(-1), mean: 1138ngg(-1)) and the German levels were from 330 to 2069ngg(-1) (median: 71ngg(-1), mean: 361ngg(-1)). PBDE contamination of lint was found in all samples; the source of the PBDEs may be from dryer electrical components and/or dust deposition onto clothing.

Multimedia modeling of polybrominated diphenyl ether emissions and fate indoors

We adapted an indoor multimedia fugacity model to consider emissions and fate of polybrominated diphenyl ethers (PBDEs) and to understand the variability of indoor concentrations. The model was applied to an office in which an 80% decrease in PBDE air concentration was observed after an old computer was exchanged with a newer one. PBDE-impregnated polyurethane foam (PUF) and carpet were treated as pseudo-steady-state components with specified fugacities derived from measured concentrations of 173 and 2140 ng x g(-1), respectively. Emission rates of 35 and 5.4 ng x h(-1), for the old and new computers, respectively, were calculated using the pseudo-steady-state approach. Particle movement (deposition and resuspension) dominates within-room transport processes, and dust removal (vacuuming) and air advection (ventilation) are the main loss processes. The most sensitive parameters to air concentrations and estimated emission rates are room temperature, particle concentrations and deposition velocity, and air exchange rates. The air exchange rates and bouncing on PUF furniture can alter whether the PUF and carpet are sources or sinks of PBDEs. Model results suggest that exposure via air can be reduced by removing dust, having a high air exchange rate, and low indoor temperatures.

Polybrominated diphenyl ether (PBDE) levels in dust from previously owned automobiles at United States dealerships

The levels of BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, and BDE-209 were determined in the dust sampled from 60 automobiles that were available for resale at U.S. dealerships. The dominant congener in automobile dust was BDE-209 comprising 95% of the total PBDE levels with a median level of 48.1 microg g(-1). Statistical analysis of the vehicle attributes indicates that the BDE-209 levels are different (p<0.05) with respect to groupings by vehicle model year, vehicle manufacturer, and the country of manufacture. Vehicle dust samples contained the characteristic profile of the PBDE congeners that comprise the PentaBDE formulation. While DecaBDE use is banned in Maine and Washington and is targeted for restriction in the near future by six U.S. states, vehicles and airplanes are exempt from the ban. It is anticipated that the human exposure potential to PBDEs from automobile dust ingestion will continue for an indefinite future period in the U.S. population.

Innovative application of fluoro tagging to trace airborne particulate and gas-phase polybrominated diphenyl ether exposures

Polybrominated diphenyl ethers (PBDEs) are flame retardants applied as coatings to many consumer products, including household items. PBDEs are released and produce airborne vapors and dusts. Inhalation of particle-phase and/or gas-phase PBDEs is therefore a major route of exposure. In an attempt to mimic realistic airborne exposures, actual uptake, and deposition of particles and vapors, we prepared and characterized particles for future animal exposure studies. To trace the particles in environmental and biological systems, we employed fluoro tagging. We synthesized, characterized, and employed three PBDE congeners, 35, 47, and 99, and five fluoro-substituted PBDEs (F-PBDEs), 17-F5' 25-F5', 28-F3', 35-F5', 47-F3, and 99-F3', for this study. The PBDE congeners were selected because they are commonly found in house dust. For that reason, we coated spherical silica particles of 3 microm and C18 endcapped silica as representative and inert support materials, with 20, 30, and 40% PBDEs. We determined the particle size distributions by aerodynamic particle size spectrometry and the morphology by scanning electron microscopy. The suitability of the fluoro-tagged tracers to mimic their corresponding parent PBDEs was investigated by extraction studies from spiked blood serum. Our study is of fundamental importance to the development of xenobiotic tracers for monitoring routes of human exposure to PBDEs and understanding uptake of PBDEs from particles and vapors.

Existence state of bromine as an indicator of the source of brominated flame retardants in indoor dust

Indoor dust is an important medium for human exposure to brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs). In this study, we used micro X-ray fluorescence spectrometry (XRFS), digital optical microscopy, and gas chromatography-high resolution mass spectrometry to investigate the existence state of bromine as an indicator of the source of BFRs in indoor dusts and in dusts from the interior of televisions collected in Japan. By means of micro XRFS bromine mapping conducted at a 0.5-s dwell time, we were able to detect bromine levels as low as about 0.1% at each point of about a beam diameter of 50 microm across. The presence of fragments containing 1.0% or more bromine was confirmed in 27 of the 48 dust samples tested. Using magnified images of the fragments, we classified them roughly into particulates and fibrous substances. We analyzed PBDEs in the fragments containing high concentrations of bromine (> or = 0.1%) and confirmed that the fragments contained PBDEs, mainly BDE 209. Furthermore, to detect bromine concentrations < or = 0.1% in the dust samples, we analyzed the samples at a dwell time of 100 s to enhance the detection sensitivity of mapping; atthis dwell time, we confirmed the presence of bromine in the dust coating. Our results suggest that bromine is transferred from products to dust matrixes not only through miniaturization and subsequent direct migration into dust as plastic and textile fragments but also through other pathways such as vaporization and airborne transfer of microparticulates.

Distribution of polybrominated diphenyl ethers in breast milk from North China: implication of exposure pathways

The breast milk concentrations of polybrominated diphenyl ethers (PBDEs; sum of eight congeners: BDE-28, 47, 99, 100, 153, 154, 183 and 209) were determined (by high resolution gas chromatographic high resolution mass spectrometry) in samples from primiparous women collected in 2006 in Tianjin, China. Dietary and lifestyle habits of the participants were obtained by questionnaires. The median total PBDE concentration (including BDE-28, 47, 99, 100, 153, 154, 183) was 2500 pg g(-1) lipid weight, ranging from 1700 to 4500 pg g(-1) lipid weight. These levels were in the same range as those from Europe and Japan but much lower than those from North America. The congener profile in China was also different from other countries. The contribution of BDE-28 was around 15%, much higher than any other country, implying that a different Penta-BDE formulation might be used in the Chinese market. The lower ratio of the sum of BDE-47, 99, and 100 to the sum of BDE-153 and 154 suggested that Octa-products were in more demand in China. A significant correlation was found between a woman's PBDE concentration and the time she used electronic appliances (h/d). This implies that electronics are a potential source of PBDEs to people. Inhalation or ingestion of particulate matter (such as dust) may also be an important exposure pathway. There was no significant correlation between the PBDE concentration and the consumption of meat, fish, and milk. Further research is needed to determine the specific contribution of each exposure route and their health effects.

Participant experiences in a breastmilk biomonitoring study: a qualitative assessment

BACKGROUND

Biomonitoring studies can provide information about individual and population-wide exposure. However they must be designed in a way that protects the rights and welfare of participants. This descriptive qualitative study was conducted as a follow-up to a breastmilk biomonitoring study. The primary objectives were to assess participants' experiences in the study, including the report-back of individual body burden results, and to determine if participation in the study negatively affected breastfeeding rates or duration.

METHODS

Participants of the Greater Boston PBDE Breastmilk Biomonitoring Study were contacted and asked about their experiences in the study: the impact of study recruitment materials on attitudes towards breastfeeding; if participants had wanted individual biomonitoring results; if the protocol by which individual results were distributed met participants' needs; and the impact of individual results on attitudes towards breastfeeding.

RESULTS

No participants reported reducing the duration of breastfeeding because of the biomonitoring study, but some responses suggested that breastmilk biomonitoring studies have the potential to raise anxieties about breastfeeding. Almost all participants wished to obtain individual results. Although several reported some concern about individual body burden, none reported reducing the duration of breastfeeding because of biomonitoring results. The study literature and report-back method were found to mitigate potential negative impacts.

CONCLUSION

Biomonitoring study design, including clear communication about the benefits of breastfeeding and the manner in which individual results are distributed, can prevent negative impacts of biomonitoring on breastfeeding. Adoption of more specific standards for biomonitoring studies and continued study of risk communication issues related to biomonitoring will help protect participants from harm.

Design and performance evaluation of a medium flow sampler for airborne brominated flame retardants (BFRs)

Brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs), have emerged as important and ubiquitous environmental pollutants, and there is a need to accurately measure airborne levels of these chemicals in both indoor and outdoor applications. We review and suggest performance criteria for BFR sampling systems, and then present the design of a new medium flow active sampler. The sampler uses a PTFE filter (47 mm, 1 microm pore size) in front of a polyurethane foam (PUF) adsorbent plug (22 mm dia, 76 mm length) with a nominal flow rate of 15 L min(-1) and a sampling period of one week, giving a sampling volume of 150 m(3). The sampler was evaluated using co-located systems to test precision, backup PUFs to test breakthrough, and distributed volume sampling to test linearity. Field experiments were conducted in five commercial buildings, one residence and outdoors at an urban site. A total of 20 BDE congeners were quantified. After appropriate cleaning of the PUF adsorbent, blank levels were negligible. Method detection limits (MDLs) were sufficiently low to quantify BDE congeners 17, 28, 71, 47, 100 and 99 in ambient air, and more than adequate to quantify these and other congeners in indoor air, where levels are typically much higher. The relative absolute deviation (RAD), based on distributed volume samples, ranged from 21% (BDE-71) to 81% (BDE-75) for indoor samples, and was somewhat higher for ambient samples. Only minimal breakthrough was detected in back-up samples, and over 80% of the samples had very low or negligible breakthrough. Humidity did not influence sampler performance. Overall, the medium-flow sampler can accurately measure PBDEs over a wide range of concentrations and applications.

Occurrence and congener specific profiles of polybrominated diphenyl ethers and their hydroxylated and methoxylated derivatives in breast milk from Catalonia

The presence of polybrominated diphenyl ethers (PBDEs) from mono to hepta brominated and 11 hydroxylated (OH-) and methoxylated (MeO-) PBDEs was examined in 37 breast milk samples collected from 11 mothers living in Barcelona. An extraction method based on accelerated solvent extraction followed by gas chromatography coupled to high resolution mass spectrometry was used to inequivocally identify all target compounds at the low pg g(-1) lw level. Data obtained were examined for absolute and relative concentrations and specific PBDE, OH- and MeO-PBDE congener patterns. Sigma PBDE concentration ranged between 1,161 and 1,372,797 pg g(-1) lw and BDEs 47, 99, 100, 153 and 183 accounted for more than 80% of the total PBDEs. All tri and tetra OH- and MeO-PBDEs compounds were detected at levels between 6 and 14,984 pg g(-1)lw. The median ratio OH/PBDE and MeO-PBDEs/PBDEs was from 2.9% to 1.6%, respectively, suggesting either that PBDE metabolism to OH- and MeO- derivatives is not an important degradation route in humans or either OH- and MeO-PBDEs are rapidly excreted. No significant correlation was observed between PBDEs and OH- and MeO-PBDE, although OH- and OMe-PBDEs co-occurred in mothers' milk (R(2)=0.5349). According to the daily intake of PBDEs and OH- and MeO-PBDEs, which was between 0.47 and 363 ng d(-1) (excluding a smoking donor), potential health risks associated with these compounds are assessed.

Perinatal exposure to brominated flame retardants and polychlorinated biphenyls in Japan

Brominated flame retardants (BFRs) are used to prevent combustion in consumer products. Examples of BFRs are polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A (TBBPA), and tribromophenol (TBP). These compounds are reported to have adverse effects on human health and endocrine disrupting effects. The purpose of this study was to identify the Japanese perinatal exposure to PBDEs, hydroxylated PBDE metabolites (OH-PBDEs), TBBPA, and TBP compared with polychlorinated biphenyls (PCBs) and hydroxylated PCB metabolites (OH-PCBs). We investigated the concentrations of these compounds in maternal blood, maternal milk, cord blood, and umbilical cords from 16 Japanese mother-infant pairs by HRGC/HRMS. PBDEs were detected in all samples of maternal blood (mean+/-SD; median=25+/-23 pg/g; 18 pg/g wet weight), maternal milk (140+/-220 pg/g; 59 pg/g wet weight), cord blood (4.8+/-6.5 pg/g; 1.6 pg/g wet weight), and umbilical cords (3.1+/-3.1 pg/g; 2.1 pg/g wet weight). The mothers were divided into two groups, a high-concentration group and a low-concentration group. The percentage of BDE-47 showed the greatest difference between the two groups. 6-OH-BDE-47, TBBPA, and TBP were detected in all umbilical cord samples (mean+/-SD; median=8.4+/-8.1 pg/g; 8.0 pg/g, 16+/-5.5 pg/g; 15 pg/g, and 33+/-8.2 pg/g; 32 pg/g wet weight respectively), but not in all maternal blood or cord blood samples. These results indicate that OH-PBDEs, TBBPA, and TBP, in addition to PBDEs, PCBs, and OH-PCBs, pass through the blood-placenta barrier and are retained in the umbilical cord.