Assessment of human exposure to polybrominated diphenyl ethers in China via fish consumption and inhalation

This study examined human exposure to polybrominated diphenyl ethers (PBDEs) associated with fish consumption and inhalation in China. The median intake of sigma7 PBDEs via human milk was 48.2 ng/day for nursing infants (0-1 years old) (a range of 23.4-99.1 ng/day). For all other age groups, the median intake of sigma11 PBDEs via fish consumption was 1.7-12.9 ng/day with a range of 0.59-56.3 ng/g. Additionally, human exposure to PBDEs via inhalation was 2.7-9.2 ng/day (a range of 0.72-108 ng/day). The median total sigma11 PBDEs intakes for nursing infants (6874 and 7372 pg/ kg b.w./day for males and females, respectively) were much higher than other age groups (215-608 pg/kg b.w./ day). No significant difference in the total PBDEs intakes was found between males and females. Of the 11 PBDEs congeners, BDE-47 was predominant in the total intake for nursing infants with a mean contribution of 38%, whereas BDE-209 was the dominant congener of total intake for other age groups, varying from 44 to 61%. Currently, the PBDEs levels in Chinese consumer fish and the total intakes of PBDEs via fish consumption were at the lower end of the global range. Compared with similar studies in other countries, however, human exposure to PBDEs via inhalation in China was relatively high. Overall, estimated daily intake of total PBDEs in the Chinese population was far below the LOAEL. However, studies are needed to further understand the fate and impact of PBDEs as PBDE-containing products are still used widely in large quantities in China.     

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.     

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.     

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.     

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.     

Detection of polybrominated diphenyl ethers in herring gull (Larus argentatus) brains: effects on mRNA expression in cultured neuronal cells

In recent years, polybrominated diphenyl ethers (PBDEs) have been detected at increasing levels in the environment due to their widespread use as flame retardants. PBDEs can affect thyroid hormone homeostasis and the cholinergic neurotransmitter system. In this study, several PBDE congeners were detected in whole brain samples and neuronal cells of herring gulls (Larus argentatus). A herring gull neuronal cell culture method was used to determine the effects of PBDEs on cytotoxicity and mRNA expression. Real-time RT-PCR assays were developed for genes associated with the thyroid hormone pathway (thyroid hormone receptors [TR alpha and beta], transthyretin [TTR]), and the cholinergic system (neuronal nicotinic acetylcholine receptor alpha-7 [nAChR alpha-7]). Administration of T3 resulted in a significant up-regulation of the two TRs and a significant down-regulation of TTR. TTR was also down-regulated by the commercial penta-BDE mixture, DE-71. In contrast, neither DE-71, nor BDE-47, -99, or -100 altered the mRNA levels of the TRs or nAChR alpha-7. The in vitro approach was a relevant model system for assessing the effects of PBDEs on cytotoxicity and mRNA expression. Herring gull neuronal cells were responsive to both T3 and PBDEs although, receptors associated with two predicted mechanisms of PBDE action were not effective molecular biomarkers of exposure.     

Prenatal Transfer of Polybrominated Diphenyl Ethers (PBDEs) Results in Developmental Neurotoxicity in Zebrafish Larvae

Parental exposure to polybrominated diphenyl ethers (PBDEs) in animals has been found to be transferred to the offspring. The environmental health risk and toxicity to the offspring are still unclear. The objective of the present study was to identify environmentally relevant concentrations of PBDEs for parental exposure that would cause developmental neurotoxicity in the offspring. Adult zebrafish were exposed to environmentally relevant concentrations of DE-71 (0.16, 0.8, 4.0 μg/L) via water. The results showed that PBDE exposure did not affect larvae hatching, malformation, or survival. The residue of PBDEs was detected in F1 eggs upon parental exposure. Acetylcholinesterase (AChE) activity was significantly inhibited in F1 larvae. Genes of central nervous system development (e.g., myelin basic protein, synapsin IIa, α1-tubulin) were significantly downregulated in larvae. Protein levels of α1-tubulin and synapsin IIa were also reduced. Decreased locomotion activity was observed in the larvae. This study provides the first evidence that parental exposure to environmentally relevant concentrations of PBDEs could cause adverse effects on neurodevelopment in zebrafish offspring.     

Measurement of polybrominated diphenyl ethers on hand wipes: estimating exposure from hand-to-mouth contact

Estimates of exposure to the flame-retardant polybrominated diphenyl ethers (PBDEs) in dust are very poor due to limited knowledge about dust ingestion. This study was undertaken to determine if PBDEs could be measured on hand wipes, and if so, to determine the distribution of levels present on the skin surface area to provide preliminary exposure estimates from hand-to-mouth contact. Hand wipes were collected from 33 individuals residing in the United States using sterile gauze pads soaked in isopropyl alcohol. The total PBDE residue collected on the wipes ranged from 2.60 to 1982 ng, with a median value of 130 ng, or normalized to hand surface area, a concentration of 135 pg/cm2. The fully brominated congener, BDE 209, was also detected and ranged from < DL to 270 ng with a median value of 26 ng. Congener patterns observed on the wipes were similar to patterns observed in house dust samples, consisting of congeners associated with the PentaBDE and DecaBDE mixtures, suggesting that the source of PBDEs to the hands may be dust particles. However, PBDE hand residues may also be a result of direct contact with PBDE-laden products, leading to adsorption to the skin surface oils. Repeated wipe sampling from three individuals suggests that sigmaPBDE levels on the hand may be relatively consistent for some individuals but not for others. Furthermore, levels of sigmaPBDEs were greater on the bottom of the hands relative to the top of the hands. Using these values we have calculated potential human exposure from hand-to-mouth contact. The median exposure estimates for children and adults are 1380 and 154 ng/day, respectively, whereas the 95th percentile exposure estimates were 6090 and 677 ng/day, respectively. These estimates are greater than dietary intake rates and suggest hand-to-mouth contact may be a key exposure route for PBDEs.     

Parental transfer of polybrominated diphenyl ethers (PBDEs) and thyroid endocrine disruption in zebrafish

Polybrominated diphenyl ethers (PBDEs) have the potential to disrupt the thyroid endocrine system. The objective of the present study was to characterize the disrupting effects of long-term exposure on the thyroid endocrine system in adult fish and their progeny following parental exposure to PBDEs. Zebrafish (Danio rerio) embryos were exposed to environmentally relevant concentrations (1, 3, and 10 μg/L) of the PBDE mixture DE-71 for 5 months until sexual maturation. In the F0 generation, exposure to DE-71 significantly increased plasma thyroxine (T4) but not 3,5,3'-triiodothyronine (T3) in females. This increased T4 was accompanied by decreased mRNA levels of corticotropin-releasing hormone (CRH) and thyrotropin β-subunit (TSHβ) in the brain. The F1 generation was further examined with or without continued DE-71 treatment conditions. Exposure to DE-71 in the F0 fish caused significant increases in T4 and T3 levels in the F1 larvae and modified gene expressions in the hypothalamic-pituitary-thyroid axis (HPT axis) under both conditions. Decreased hatching and inhibition of growth in the F1 offspring were observed in the condition without DE-71 treatment. Continued DE-71 treatment in the F1 embryos/larvae resulted in further decreased hatching, and increased malformation rates compared with those without DE-71 exposure. Analysis of F1 eggs indicated that parental exposure to DE-71 could result in a transfer of PBDEs and thyroid hormones (THs) to their offspring. For the first time, we demonstrated that parental exposure to low concentrations of PBDEs could affect THs in the offspring and the transgenerational PBDE-induced toxicity in subsequent nonexposed generations.     

我国母乳中持久性有机污染物机体负荷研究进展

母乳是世界卫生组织推荐的作为人生物监测的理想基质,也是履行《关于持久性有机污染物的斯德哥尔摩公约》成效评估的主要基质。为评估普通人群持久性有机污染物机体负荷水平及履约成效评估需要,我国自2007年以来连续开展母乳监测工作,重点对多氯代二苯并二噁英和多氯代二苯并呋喃、多氯联苯、多溴二苯醚等典型持久性有机污染物开展相关监测。获得了表征我国普通人群机体负荷水平的代表性数据以及时空分布状况,为我国履约工作提供了有力支撑。     

Polybrominated diphenyl ethers contamination of United States food

Elevated levels of polybrominated diphenyl ethers (PBDEs), a type of brominated flame retardant, were recently detected in U.S. nursing mothers' milk. These halogenated compounds chemically and toxicologically resemble others such as polychlorinated biphenyls (PCBs), whose route of intake is almost exclusively through food of animal origin. This study is the first to report the levels of PBDEs in U.S. foods in a market basket survey of 30 food types (total of 32 food samples) from three major supermarket chains in Dallas, TX. Food samples were almost exclusively foods of animal origin: meat, fish, and dairy products. Thirteen PBDE congeners were measured for each sample. Levels were then compared to existing PBDE food studies from other countries where available. In this study, levels of PBDEs are highest in fish, then meat, and lowest in dairy products; median levels were 1725 (range 8.5-3078), 283 (range 0.9-679), and 31.5 (0.2-1373), parts per trillion (ppt), or pg/g, wet weight, respectively. Nonfat milk did not have any detectable PBDE levels. In fish, PBDE congener 47 (2,2',4,4'-tetraBDE) contributes up to 70% of the total PBDEs, followed by congeners 100 (2,2',4,4',6) and 99 (2,2',4,4',5). In meat congener 99 predominates, followed by 47. In dairy, BDE 47 predominates followed by 99. U.S. food PBDE levels measured in this study are higher than reported in two other published market based studies from Spain and Japan. Although these findings are preliminary and will be updated with analyses of new samples, they suggest that food is a major route of intake for PBDEs.     

Total consumer exposure to polybrominated diphenyl ethers in North America and Europe

Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants in textiles, polyurethane foams, and plastics. PBDEs exert toxic effects in various organisms, including humans, and are ubiquitous in the outdoor and indoor environment. Here we estimate total daily PBDE doses received by consumers in North America and Europe, along with the most important pathways and congeners, and derive PBDE elimination half-lives for chronic exposure. We estimate distributions for all parameters (PBDE concentrations in exposure media, food consumption rates, etc.) and conduct a probabilistic exposure assessment. We find that Americans are exposed the most, likely due to stricter fire regulations, followed by consumers from the UK and Continental Europe. In the central quantiles of the exposure distributions derived, food is the dominant pathway; in the upper quantiles either food or oral and dermal exposure to dust. This reflects the lipophilic and persistent nature of PBDEs and their use in products for indoor-use. Median elimination half-lives are in a range of 1-3 years except for BDE-153 with about seven years and BDE-209 with 4-7 days.     

Determination of phthalic acid diesters in human milk at low ppb levels

Phthalic acid diesters (PAE) are omnipresent in the human environment and food is a major contributor to the overall human exposure towards these chemicals. Due to developmental effects, PAE infants’ exposure via human milk has been subjected to a number of analytical studies. These previous studies, however, revealed that normal laboratory blank values are in the range of or even higher than human milk levels due to the presence of PAE in laboratory environments. In order to provide more reliable data on PAE exposure via human milk, the aim of this study was to develop and validate a robust and sensitive analytical method. This should be capable of removing matrix components efficiently and guarantee limits of quantification in the low ppb range. The method development took into account liquid–liquid extraction and selective pressurised fluid extraction (sPFE) as well as chromatography-based clean-up steps. The final method consisted of a liquid–liquid extraction followed by an automated chromatographic clean-up by an sPFE device. After volume reduction the cleaned extracts were analysed by quadrupole GC/MS. Quantification was based on internal standards. An extensive quality assurance and method test programme demonstrated conservatively determined limits of detection and quantification from 0.3 to 10?ng?g^?1 in human milk, with recoveries of internal standards from 50% to 101%. Thus, the method allowed the quality-assured detection of di-isobutyl phthalate (DiBP), di-n-butyl phthalate (DBP), di-2-ethylhexyl phthalate (DEHP), di-allyl phthalate (DAP), benzylbutyl phthalate (BBP) and di-cyclohexyl phthalate (DcHP) in 30 human milk samples provided by 30 volunteers from southern Germany. DiBP, DBP and DEHP were the most commonly detected PAE, with median levels of 1.0, 0.6 and 2.3?ng?g^?1, respectively.     

Evaluating daily exposure to polychlorinated biphenyls and polybrominated diphenyl ethers in fish oil supplements

Fish oil supplements have become a popular means of increasing one's dietary intake of essential polyunsaturated fatty acids. However, there is growing concern that the levels and potential health effects of lipophilic organic contaminants such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) may diminish some of the health benefits associated with the daily consumption of fish oil supplements. In this study, ten over-the-counter fish oil supplements available in the United States were analysed for PCBs and PBDEs and daily exposures calculated. Based on manufacturers’ recommended dosages, daily intakes of PCBs and PBDEs ranged from 5 to 686 ng day^?1 and from 1 to 13 ng day^?1, respectively. Daily consumption of fish oil supplements expose consumers to PCBs and PBDEs. However, in comparison with fish ingestion, fish supplements may decrease daily PCB exposure and provide a safer pathway for individuals seeking to maintain daily recommended levels of polyunsaturated fatty acids.     

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.     

Distribution of polybrominated diphenyl ethers in human umbilical cord serum, paternal serum, maternal serum, placentas, and breast milk from Madrid population, Spain

Median concentration of total PBDEs in maternal serum, paternal serum, umbilical cord serum, and breast milk samples were 12, 12, 17, and 6.1 ng/g lipid weight (lw) in Vallecas and 9.7, 12, 15, and 5.5 ng/g lw in Getafe. The median value found in placentas was 1.9 ng/g lw (in Vallecas). BDE 47 was the predominant congener in serum samples (maternal, paternal, and umbilical cord), while BDE 209 was predominant in placenta and breast milk samples. BDEs 196 and 197 were detected in most of the placenta and breast milk samples. The results show that PBDEs, like other POPs, can cross the placenta barrier, although the speed of the process seems to differ for each PBDE congeners. The total PBDE concentrations found in this study are consistent with research reported elsewhere. They are in the same range as those recently reported by other European and Asian studies and lower than those conducted in the U.S.A. No significant differences were found (p > 0.05) between regions, sexes, and ages, while statistically significant differences (p < 0.05) were found between maternal serum, umbilical cord serum, and breast milk samples. The presence of PBDEs in cord blood and placenta samples indicates that there is prenatal exposure of PBDEs, which could continue after birth via breast milk.     

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.     

NUTRITIONAL ASPECTS OF MILK PROTEIN

The significance of milk proteins in human nutrition is discussed in the light of the considerable advances in the understanding of their chemistry which have been made recently. In particular comparison is made of the effectiveness of milk proteins and those from other sources in fulfilling human requirements for essential amino acids and attention is drawn to the possible significance of the predominantly phospho-protein character of milk proteins. Finally consideration is given to the use of milk proteins as the basic raw material for specialist preparations designed to meet nutritional requirements in circumstances of abnormal protein metabolism and to possible ill effects to be expected from ingestion of milk protein.     

Dietary exposure to brominated flame retardants correlates with male blood levels in a selected group of Norwegians with a wide range of seafood consumption

This study investigates dietary exposure and serum levels of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) in a group of Norwegians (n = 184) with a wide range of seafood consumption (4-455 g/day). Mean dietary exposure to Sum 5 PBDEs (1.5 ng/kg body weight/day) is among the highest reported. Since concentrations in foods were similar to those found elsewhere in Europe, this may be explained by high seafood consumption among Norwegians. Oily fish was the main dietary contributor both to Sum PBDEs and to the considerably lower HBCD intake (0.3 ng/kg body weight/day). Milk products appeared to contribute most to the BDE-209 intake (1.4 ng/kg body weight/day). BDE-209 and HBCD exposures are based on few food samples and need to be confirmed. Serum levels (mean Sum 7 PBDEs = 5.2 ng/g lipid) and congener patterns (BDE-47 > BDE-153 > BDE-99) were comparable with other European reports. Correlations between individual congeners were higher for the calculated dietary exposure than for serum levels. Further, significant but weak correlations were found between dietary exposure and serum levels for Sum PBDEs, BDE-47, and BDE-28 in males. This indicates that other sources in addition to diet need to be addressed.     

Emerging contaminants in car interiors: evaluating the impact of airborne PBDEs and PBDD/Fs

Air samples from automobile cabins were collected and analyzed for polybrominated diphenyl ethers (PBDEs), polybrominated dibenzofurans (PBDFs), and polybrominated dibenzo-p-dioxins (PBDDs). The concentration of total PBDEs (sigmaPBDE; sum of 19 congeners) varied from 0.4 to 2644 pg m(-3), with a median of 201 pg m(-3), while BDE 47, 99, and 209 collectively accounted for 70 +/- 30% of sigmaPBDE concentrations. Multiple linear regression analysis revealed that sigmaPBDE concentration was significantly influenced by vehicle's age and interior temperature. More specifically, sigmaPBDE decreased over time and increased with the rise of temperature. The daily inhalation intake of PBDEs during commuting was estimated to range from 0.5 to 2909 pg day(-1) (median 221 pg day(-1)) and contributed 29% of the overall daily exposure to PBDEs via inhalation. When excluding BDE 209, a lower contribution was calculated for this source (18%), but this was still comparable with residential exposure (22%). The levels of PBDD/Fs were generally below the limits of detection and only in one case were hepta-BDFs positively detected at a concentration of 61 pg m(-3). This study demonstrates that car interiors, especially when new, contain high levels of airborne PBDEs and represent a potential route of human exposure via inhalation.