Polybrominated diphenyl ethers in indoor dust in Ottawa, Canada: implications for sources and exposure

Polybrominated diphenyl ethers (PBDEs) are widely used as additive flame retardants in plastics, soft furnishings, electrical and electronic equipment, and insulation in the indoor environment, and may be released indoors via volatilization or as dusts. The penta-and octa-brominated mixes are now banned in most parts of Europe, and phasing out of their use has recently begun in North America. This study follows a previous investigation into indoor air levels of PBDEs. House dust was analyzed from the family vacuum cleaners of 68 of the same 74 randomly selected homes, in Ottawa, Canada during the winter of 2002-2003. PBDEs, comprising on average 42% BDE-209, were found in all samples. The levels were log-normally distributed with a geometric mean sigmaPBDE of 2000 ng g(-1), and a median of 1800 ng g(-1) dust. The levels in dust did not correlate with questionnaire information on house characteristics. Correlations were found between pentamix congener levels in dust and in air from the same homes, but not for congeners of the more highly brominated mixes. Exposure scenarios are presented for mean and high dust ingestion rates, and compared against exposures from other pathways, for both adults and toddlers (6 months-2 years). Assuming a mean dust ingestion rate and median dust and air concentrations, adults would be exposed to ca. 7.5 ng sigmaPBDE d(-1) via the dust ingestion pathway, which represents approximately 14% of total daily exposure when compared to diet (82%) and inhalation (4%). However, for toddlers the equivalent intakes would be 99 ng d(-1), representing 80% of their daily PBDE exposure. At high dust ingestion rates these values increase to 180 ng d(-1) (80% daily intake) for adults and 360 ng d(-1) (89% daily intake) for toddlers. The data give a clearer picture of sources of PBDE exposure in the home environment and suggest that dust could be a significant exposure pathway for some individuals, particularly children.     

Polybrominated diphenyl ethers in house dust and clothes dryer lint

Few studies have measured the flame retardants polybrominated diphenyl ethers (PBDEs) in the indoor environment. Here, we report measurements of PBDEs in house dust samples collected from the Washington, D.C. metropolitan area in the United States. Dust samples were analyzed for 22 individual PBDE congeners and our results found PBDEs present in every sample. Concentrations of total PBDEs ranged from 780 ng/g dry mass to 30 100 ng/g dry mass. The dominant congeners observed in the dust samples were congeners associated with the pentaBDE and decaBDE commercial mixtures. Ancillary data were collected on the homes and examined for any correlations with total PBDE concentrations. No correlations were observed with year of house construction, type of flooring (i.e., hardwood vs carpet) or the number of television sets or personal computers in the home. However, a significant inverse correlation (p < 0.05) was observed between the area of the home and the contribution of BDE 209 to the total PBDE concentration in dust. Using estimates of inadvertent dust ingestion (0.02-0.2 g/day) by young children (ages 1-4), we estimate ingestion of total PBDEs to range from 120 to 6000 ng/day. Clothes dryer lint was also sampled and analyzed for PBDEs from five of the homes and were present in all five samples ranging from 480 to 3080 ng/g dry mass. This study demonstrates that PBDEs are prevalent at relatively high concentrations within homes where people, and particularly young children, may be susceptible to exposure.     

Elevated PBDE levels in pet cats: sentinels for humans?

Co-incident with the introduction of polybrominated diphenyl ethers (PBDEs) into household materials nearly 30 years ago, feline hyperthyroidism (FH) has increased dramatically. Risk of developing FH is associated with indoor living and consumption of canned catfood. We hypothesized that increases in FH were, in part, related to increased PBDE exposure, with key routes of exposure being diet and ingestion of house dust. This study was designed to determine whether body burdens of PBDEs in hyperthyroid (HT) cats were greater than that of young or sick non-HT cats. Serum samples and clinical information were collected from 23 cats. Serum and dry and canned cat food were analyzed for PBDEs. A spectrum of BDE congeners was detected in all cats, with BDE-47, 99, 207, and 209 predominating. Mean +/- standard error (and median) cumulative sigma PBDE serum concentrations of young, old non-HT, and HT cats were 4.3 +/- 1.5 (3.5), 10.5 +/- 3.5 (5.9), and 12.7 +/- 3.9 (6.2) ng/mL, respectively. Due to high variability within each group, no association was detected between HT cats and sigma PBDE levels. Indicative of age- or disease-dependent changes in PBDE metabolism, BDE-47/99 ratios were inversely correlated with age, and 47/99 and 100/ 99 ratios in HT cats were significantly lower than those in the other cats. Overall, sigma PBDE levels in cats were 20- to 100-fold greater than median levels in U.S. adults. Our results support the hypothesis that cats are highly exposed to PBDEs; hence, pet cats may serve as sentinels to better assess human exposure and adverse health outcomes related to low-level but chronic PBDE exposure.     

Sources, emissions, and fate of polybrominated diphenyl ethers and polychlorinated biphenyls indoors in Toronto, Canada

Indoor air concentrations of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) measured in 20 locations in Toronto ranged 0.008-16 ng·m(-3) (median 0.071 ng·m(-3)) and 0.8-130.5 ng·m(-3) (median 8.5 ng·m(-3)), respectively. PBDE and PCB air concentrations in homes tended to be lower than that in offices. Principal component analysis of congener profiles suggested that electrical equipment was the main source of PBDEs in locations with higher concentrations, whereas PUF furniture and carpets were likely sources to locations with lower concentrations. PCB profiles in indoor air were similar to Aroclors 1248, 1232, and 1242 and some exterior building sealant profiles. Individual PBDE and PCB congener concentrations in air were positively correlated with colocated dust concentrations, but total PBDE and total PCB concentrations in these two media were not correlated. Equilibrium partitioning between air and dust was further examined using log-transformed dust/air concentration ratios for which lower brominated PBDEs and all PCBs were correlated with K(OA). This was not the case for higher brominated BDEs for which the measured ratios fell below those based on K(OA) suggesting the air-dust partitioning process could be kinetically limited. Total emissions of PBDEs and PCBs to one intensively studied office were estimated at 87-550 ng·h(-1) and 280-5870 ng·h(-1), respectively, using the Multimedia Indoor Model of Zhang et al. Depending on the air exchange rate, up to 90% of total losses from the office could be to outdoors by means of ventilation. These results support the hypotheses that dominant sources of PBDEs differ according to location and that indoor concentrations and hence emissions contribute to outdoor concentrations due to higher indoor than outdoor concentrations along with estimates of losses via ventilation.     

Is house dust the missing exposure pathway for PBDEs? An analysis of the urban fate and human exposure to PBDEs

Polybrominated diphenyl ether (PBDE) body burdens in North America are 20 times that of Europeans and some "high accumulation" individuals have burdens up to 1-2 orders of magnitude higher than median values, the reasons for which are not known. We estimated emissions and fate of sigma PBDEs (minus BDE-209) in a 470 km2 area of Toronto, Canada, using the Multi-media Urban Model (MUM-Fate). Using a combination of measured and modeled concentrations for indoor and outdoor air, soil, and dust plus measured concentrations in food, we estimated exposure to sigma PBDEs via soil, dust, and dietary ingestion and indoor and outdoor inhalation pathways. Fate calculations indicate that 57-85% of PBDE emissions to the outdoor environment originate from within Toronto and that the dominant removal process is advection by air to downwind locations. Inadvertent ingestion of house dust is the largest contributor to exposure of toddlers through to adults and is thus the main exposure pathway for all life stages other than the infant, including the nursing mother, who transfers PBDEs to her infant via human milk. The next major exposure pathway is dietary ingestion of animal and dairy products. Infant consumption of human milk is the largest contributor to lifetime exposure. Inadvertent ingestion of dust is the main exposure pathway for a scenario of occupational exposure in a computer recycling facility and a fish eater. Ingestion of dust can lead to almost 100-fold higher exposure than "average" for a toddler with a high dust intake rate living in a home in which PBDE concentrations are elevated.     

Dietary intake and risk evaluation of polybrominated diphenyl ethers in The Netherlands

The current study aims at estimating the dietary intake of PBDEs in the Netherlands and evaluating the resultant risk. Dietary intake was estimated using results of PBDE analyses in Dutch food products from 2003/2004 and consumption data of the third Dutch National Food Consumption Survey (1997/1998). Assuming that non-detects represent levels of half the detection limit, the median long-term intake of the Dutch population of the sum of five major PBDEs (namely PBDEs 47, 99, 100, 153+154) is 0.79 ng/kg body weight bw/day (P97.5: 1.62 ng/kg bw/day). When non-detects are considered as zeros the values are 0.53 (median) and 1.34 (P97.5) ng/kg bw/day. Environmental concentrations of PBDEs in Europe are expected to decline in the near future because of the ban on penta- and octaBDE technical products. However, it will take at least a decade before this will result in lower PBDE concentrations in food products. Hence, a regular monitoring program for PBDEs is recommended. A risk evaluation at the most sensitive endpoints of BDE 99 carried out in this paper indicates that, although the long-term exposure to BDE 99 is well below the human exposure threshold level for neurodevelopmental toxicity, it may be close to that for reproductive toxicity.     

High postnatal exposures to polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) via breast milk in California: does BDE-209 transfer to breast milk?

Breast milk samples collected during 2003-2005 from 82 first-time mothers in 24 communities located throughout California contained levels of polybrominated diphenyl ethers (∑(tri-hexa (8))PBDEs; median = 53.3 ng/g lw, range = 9.60-1291) and polychlorinated biphenyls (∑(12)PCBs; median = 73.4 ng/g lw, range = 22.2-433) that are among the highest in the world. PBDE levels varied 100-fold. BDE-47 was the dominant PBDE congener, with levels exceeding the U.S.EPA Reference Dose (RfD) for neurodevelopmental toxicity (100 ng/kg/day) in most (60%) breast milk samples. In some samples, BDE-209 (2/82) and/or BDE-153 (5/82) were the dominant congeners, suggesting that BDE-209 can transfer to breast milk and/or break down in the mother and transfer to the nursing infant as the lower-brominated PBDEs associated with adverse effects. PBDE levels in California breast milk are approaching those of PCBs, and the trend PBDEs > PCBs may continue as PBDEs migrate from products to the indoor and outdoor environments.     

Polybrominated diphenyl ethers and polychlorinated biphenyls in human adipose tissue from New York

Human adipose tissue samples (n=52) collected in New York City during 2003-2004 were analyzed for the presence of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). Concentrations of PBDEs in adipose tissues ranged from 17 to 9630 ng/g, lipid wt (median: 77; mean: 399 ng/g, lipid wt; sum all di- through hexaBDE congeners). Average PBDE concentrations in human adipose tissues from New York City were 10- to 100-times greater than those reported for European countries. A concentration of 9630 ng/g, lipid wt, found in a sample of adipose tissue, is one of the highest concentrations reported to date. PBDE 47 (2,2',4,4'-tetraBDE) was the major congener detected in human tissues, followed by PBDE congeners #99 (2,2',4,4',5-penta BDE), 100 (2,2',4,4',6-pentaBDE), and 153 (2,2',4,4',5,5'-hexaBDE). A few individuals contained PBDE 153 as the predominant congener in total PBDE concentrations, suggesting alternative exposure sources, possibly occupational. Principal component analysis of PBDE congener composition in human adipose tissues revealed the presence of five clusters, each characterized by varying composition. No significant difference was found in the concentrations of PBDEs between gender. Concentrations of PBDEs were, on average, similar to those for PCBs in human adipose tissues, and substantially higher when PBDE outliers were retained. PBDE and PCB concentrations were not correlated. PBDE concentrations did not increase with increasing age of the subjects, whereas concentrations of PCBs increased with increasing age in males but not in females in this study. These results suggest differences between PBDEs and PCBs in their sources or time course of exposure and disposition. The presence of comparable or greater concentrations of PBDEs, relative to PCBs, highlights the importance of recentvoluntary and regulatory effortsto cease production of commercial penta- and octa-BDE in North America, although these efforts do not address continuing emissions from existing sources, such as polyurethane foams.     

Serum levels of polybrominated diphenyl ethers (PBDEs) in foam recyclers and carpet installers working in the United States

Increased exposure to the flame retardants known as polybrominated diphenyl ethers (PBDEs) may be expected to occur during the recycling of polyurethane foam containing these chemicals. To date, no studies in the United States have investigated occupational exposure to these flame retardants during recycling processes. The objective of the present study was to determine if individuals working in foam recycling facilities, and/or carpet installers who may install carpet padding manufactured from recycled foam, possess significantly higher PBDE serum levels relative to that of the general U.S. population. As a control group, serum was collected from four spouses and one clerical worker. In addition, levels in workers were also compared to the recently published national health and nutrition examination survey (NHANES) data set on PBDEs in the general U.S. population. Serum samples were collected in duplicate and analyzed by two different laboratories as quality control. Total PBDE levels were found to be significantly higher (p < 0.05) in the individuals recycling foam and installing carpet (n = 15) relative to the control group (n = 5). Median sigmaPBDE levels in the foam recyclers, carpet layers, and control group were 160, 178, and 19 ng/g lipid, respectively. In contrast, concentrations of a polybrominated biphenyl (BB-153) and a polychlorinated biphenyl (CB-153) were equivalent among all groups tested. The PBDE congeners BDE-47, 99, 100, and 153 contributed 90% of the sigmaPBDE concentration in serum and no differences in congener patterns were apparent among the different groups. Relative to concentrations measured in the NHANES, foam recyclers and carpet layers have body burdens that are an order of magnitude higher. These data suggest individuals recycling foam-containing products, and/ or using products manufactured from recycled foam (i.e., carpet padding), have higher body burdens of PBDEs, and thus may be at higher risk from adverse health effects associated with brominated flame retardant exposure.     

Identification and determination of hexachlorocyclopentadienyl-dibromocyclooctane (HCDBCO) in residential indoor air and dust: a previously unreported halogenated flame retardant in the environment

Hexachlorocyclopentadienyl-dibromocyclooctane (HCDBCO, CAS 51936-55-1) has been detected in residential indoor air and indoor dust in Ottawa, Canada. The positive identification of the chemical was based on the interpretation of the mass spectra of the chemical obtained under both electron impact and negative chemical ionization operation modes, as well as through the synthesis of this chemical. This is the first report on the presence of HCDBCO in the environment. Although the levels of HCDBCO in indoor dust, with a geometric mean of 2.7 ng g(-1) and a median of 2.0 ng g(-1) respectively, are generally low compared to those of polybrominated diphenyl ethers (PBDEs) and dechlorane plus, another recently detected flame retardant, high levels of HCDBCO were detected in several dust samples with a maximum level of 93,000 ng g(-1) which is 16 times higher than the maximum level of the structurally related dechlorane plus. On the other hand, levels of HCDBCO in indoor air, with a geometric mean of 70 pg m(-3) and a median of 92 pg m(-3), were higher than those of the major PBDE congeners. The maximum level of HCDBCO found in indoor air was 3000 pg m(-3). Structurally, HCDBCO belongs to a group of norbornane based halogenated flame retardants. The presence of HCDBCO in the indoor environment may raise awareness of the potential release of this and related flame retardants into the environment during the production and usage of products that contain them, and the potential implications of human exposure to these chemicals as people spend the majority of their time indoors in modern society.     

Brominated flame retardants in Canadian chicken egg yolks

Chicken eggs categorised as conventional, omega-3 enriched, free range and organic were collected at grading stations in three regions of Canada between 2005 and 2006. Free run eggs, which were only available for collection from two regions, were also sampled during this time frame. Egg yolks from each of these egg types (n = 162) were analysed to determine brominated flame retardant levels, specifically polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD). PBDEs were detected in 100% of the 162 samples tested, while HBCD was observed in 85% of the egg yolks. Total PBDE concentrations in egg yolks ranged from 0.018 to 20.9 ng g(-1) lipid (median = 3.03 ng g(-1) lipid), with PBDE 209 identified as being the major contributor to ΣPBDE concentrations. In addition to PBDE 209, PBDE 99, 47, 100, 183 and 153 were important contributors to ΣPBDE concentrations. Total HBCD concentrations ranged from below the limit of detection to a maximum concentration of 71.9 ng g(-1) lipid (median = 0.053 ng g(-1) lipid). The α-isomer was the dominant contributor to ΣHBCD levels in Canadian egg yolks and was the most frequently detected HBCD isomer. ΣPBDE levels exhibited large differences in variability between combinations of region and type. ΣHBCD concentrations were not significantly different among regions, although differences were observed between the different types of egg yolks analysed in the present study.     

Polybrominated diphenyl ethers, hydroxylated polybrominated diphenyl ethers, and measures of thyroid function in second trimester pregnant women in California

Prenatal exposure to polybrominated diphenyl ethers (PBDEs) may disrupt thyroid function and contribute to adverse neurodevelopmental outcomes. We conducted a pilot study to explore the relationship between serum concentrations of lower-brominated PBDEs (BDE-17 to -154), higher-brominated PBDEs (BDE-183 to -209), and hydroxylated PBDE metabolites (OH-PBDEs) with measures of thyroid function in pregnant women. Concentrations of PBDEs, OH-PBDEs, thyroid-stimulating hormone (TSH), total thyroxine (T(4)), and free T(4) were measured in serum samples collected between 2008 and 2009 from 25 second trimester pregnant women in California. Median concentrations of lower-brominated PBDEs and OH-PBDEs were the highest reported to date in pregnant women. Median concentrations of BDE-47 and the sum of lower-brominated PBDEs (ΣPBDE(5)) were 43.1 ng/g lipid and 85.8 ng/g lipid, respectively, and the sum of OH-PBDEs (ΣOH-PBDE(4)) was 0.084 ng/mL. We observed a positive association between the weighted sum of chemicals known to bind to transthyretin (ΣTTR binders) and TSH levels. We also found positive associations between TSH and ΣPBDE(5), ΣOH-PBDE(4), BDE-47, BDE-85, 5-OH-BDE47, and 4'-OH-BDE49, and an inverse association with BDE-207. Relationships with free and total T(4) were weak and inconsistent. Our results indicate that PBDE exposures are elevated in pregnant women in California and suggest a relationship with thyroid function. Further investigation is warranted to characterize the risks of PBDE exposures during pregnancy.     

Passive sampling survey of polybrominated diphenyl ether flame retardants in indoor and outdoor air in Ottawa, Canada: implications for sources and exposure

The polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants in plastics of soft furnishings, TV sets and computers, and insulation in the indoor environment. The penta-BDEs--now banned in most parts of Europe but still used in North America--are additive flame retardants that may be released to the indoor environment via volatilization or as dusts. In this study, to investigate general population PBDE exposure, air was sampled in 74 randomly selected homes in Ottawa, Canada and at seven outdoor sites during the winter of 2002--3, using polyurethane foam (PUF) disk passive air samplers. The passive sampling rate (2.5 m3 day(-1)) was determined through a pilot study employing active and passive samplers side-by-side at selected indoor locations. Indoor air concentrations of PBDEs were log-normally distributed with a geometric mean of 120 pg m(-3) and a median of 100 pg m(-3), approximately 50 times higher than the range of outdoor air concentrations (<0.1-4.4 pg m(-3)). The maximum daily human exposure via the inhalation pathway based on median PBDE levels found in this survey was estimated to be 1.9 ng day(-1) (female) and 2.0 ng day(-1) (male), representing 4.1% (f) and 4.4% (m) of overall daily intake.     

Factors associated with serum polybrominated diphenyl ether (PBDE) levels among school-age children in the CHAMACOS cohort

Polybrominated diphenyl ethers (PBDEs) are a class of flame retardants historically used in textiles, furniture, and electronic products. Recent studies have documented widespread PBDE exposure to humans, with higher levels measured in children than adults. We analyzed 10 tri- to hepta-BDE congener levels in blood collected from 7-year old Mexican-American children living in an agriculture community in California (n = 272). The most frequently detected PBDE congeners in child serum were BDE-47, -99, -100, and -153, all of which were measured in >99% of the children. We used multiple linear regression models to examine associations between child total PBDE levels (ng/g lipid) and determinants of exposure. Factors positively associated with higher PBDE levels in the children were total PBDE levels in maternal serum during pregnancy, duration of exclusive breastfeeding, and having no safe places to play in their neighborhood. Child BMI was inversely associated with serum PBDE levels (regression p-values <0.05). Our findings confirm that exposure to the penta-BDE mixture is ongoing, and that Mexican-American children living in California may be experiencing higher PBDE exposure from their environment compared to children sampled from the general U.S. population. Additional research is needed to assess the health impacts of these exposures.     

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

This study was designed to determine the body burden of polybrominated diphenyl ethers (PBDEs) among first-time mothers in the Greater Boston, Massachusetts area and to explore key routes of exposure. We collected breast milk samples from 46 first-time mothers, 2-8 weeks after birth. We also sampled house dust from the homes of a subset of participants by vacuuming commonly used areas. Data on personal characteristics, diet, home furniture, and electrical devices were gathered from each participant using a questionnaire. Breast milk and dust samples were analyzed for PBDEs using gas chromatography/ mass spectrometry. PBDE concentrations were log-normally distributed in breast milk and dust. We found statistically significant, positive associations between PBDE concentrations in breast milk and house dust (r = 0.76, p = 0.003, not including BDE-209), as well as with reported dietary habits, particularly the consumption of dairy products (r = 0.41, p = 0.005) and meat (r = 0.37, p = 0.01). Due to low detection rates, it was not possible to draw conclusions about the association between BDE-209 in milk and dust. Our results support the hypothesis that the indoor environment and diet both play prominent roles in adult human exposure to PBDEs.     

Polybrominated diphenyl ethers (PBDEs) in biota representing different trophic levels of the Hudson River, New York: from 1999 to 2005

It has been hypothesized that a principal route of human exposure to polybrominated diphenyl ethers (PBDEs), used as flame retardants, is through fish consumption. Between 1999 and 2005 PBDE-47, -99, -100, -153, and -154 were analyzed in 3797 biological samples of 33 species of the Hudson River, New York. Approximately 98.4% of the samples contained PBDEs between 0.5 and 37 169 ng g(-1) lipid, with a median concentration of 772 ng g(-1) lipid. Yearly median sigmaPBDE concentrations fluctuated. Samples from river miles 112 and 153 contained higher sigmaPBDEs than those from other locations of the river. The 7-year median sigmaPBDE concentrations were the highest in large carnivorous fishes and the lowest in insects. The median abundance of congener PBDE-47 decreased from 80% to 63% with decreasing levels of sigmaPBDEs in the samples, while an increase from 2% to 23% was observed for PBDE-99. The median abundance of other congeners did not change with concentrations of sigmaPBDEs. Positive-, negative-, and no-correlation between sigmaPBDE concentrations and fish weight were observed for different species and for the same species from different locations of the river. The sources of PBDE contamination, diet, metabolic activity, and sediment chemistry might affect the levels of PBDEs in a fish.     

Brominated flame retardants in US food

We and others recently began studying brominated flame retardant levels in various matrices in the US including human milk and other food. This paper reviews the food studies. In our studies, ten to thirteen polybrominated diphenyl ether (PBDE) congeners were measured, usually including BDE 209. All US women's milk samples were contaminated with PBDEs from 6 to 419 ng/g, lipid, orders of magnitude higher than levels reported in European studies, and are the highest reported worldwide. We compared our market basket studies of meat, fish and dairy products with other US food studies of meat and fish. US studies showed somewhat higher levels of PBDEs than reported elsewhere. Fish were most highly contaminated (median 616 pg/g), then meat (median190 pg/g) and dairy products (median 32.2 pg/g). However, unlike some European countries where fish predominates, dietary intake of PBDEs in the US is mostly from meat, then fish and then dairy products. Broiling can decrease the amount of PBDEs per serving. We also measured levels of hexabromocyclododecane (HBCD), another brominated flame retardant, in human milk. The levels are lower than PBDEs, 0.16-1.2 ng/g, similar to European levels, unlike PBDEs where US levels are much higher than European levels.     

Consumption of fish from a contaminated lake strongly affects the concentrations of polybrominated diphenyl ethers and hexabromocyclododecane in serum

Very high concentrations of polybrominated diphenyl ethers (PBDE) have been reported in fish from Lake Mj?sa in Norway. This study was performed to examine the serum concentrations of PBDE and hexabromocyclododecane (HBCD) in consumers of fish from this lake and to investigate possible relationships between serum concentrations, self-reported fish intake and calculated total dietary PBDE exposure. Serum concentrations of the sum of the seven PBDE (BDE-28, 47, 99, 100, 153, 154 and 183) were significantly higher than those of a reference group of Norwegians eating only food with background levels of contamination (medians: 18 ng/g lipids men, 8.4 ng/g lipids women). The median dietary intake of Sum 7 PBDE was 2549 ng/day (30 ng/kg body weight/day), the highest dietary intake of PBDE reported. The contribution from fish caught from the contaminated lake comprised 98.7% of the total dietary exposure. For men, serum levels of PBDE were strongly correlated with the calculated dietary exposure, except for BDE-209. This suggests that sources other than the diet are important for human BDE-209 exposure. The median serum HBCD concentration was 4.1 and 2.6 ng/g lipids for men and women, respectively, and was also found to be associated with consumption of fish from Lake Mj?sa.     

Dietary exposure of secondary school students in Hong Kong to polybrominated diphenyl ethers from foods of animal origin

This paper reports levels of polybrominated diphenyl ethers (PBDEs) in a wide range of foods of animal origin and estimates their dietary exposure for secondary school students in Hong Kong, China. Dietary exposure to PBDEs was estimated using local food consumption data obtained from secondary school students in 2000 and the concentrations of PBDEs in food samples taken from local market in 2008. The PBDE levels on a fresh weight basis for fish ranged from 13 to 6600 pg g^?1, for seafood and seafood products ranged from 15 to 1200 pg g^?1, for meat and meat products ranged from 23 to 3500 pg g^?1, for poultry ranged from 68 to 670 pg g^?1, for eggs ranged from 280 to 800 pg g^?1, and for dairy products ranged from 12 to 480 pg g^?1. The dietary exposures of secondary school students for the average and high consumers were estimated to be 2.6 and 6.4 ng kg^?1 body weight day^?1, respectively. According to the Joint FAO/WHO Expert Committee on Food Additives (JECFA), for the more toxic PBDE congeners, adverse effects would be unlikely to occur in laboratory animals at doses of less than approximately 100 µg kg^?1 body weight day^?1. The resulting margins of exposures (38,000 for average consumers and 16,000 for high consumers) showed that the estimated dietary exposures of secondary school students were far below any adverse effect dose observed in laboratory animals and were therefore of low concern for human health.