Identilication of the novel cycloaliphatic brominated flame retardant 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane in Canadian Arctic beluga (Delphinapterus leucas)

1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH) is used primarily as an additive flame retardant. Technical grade TBECH consists of near equimolar amounts of two (of a possible four) diastereoisomers: rac-(1R,2R)-1,2-dibromo-(4S)-4-((1S)-1,2-dibromoethyl)cyclohexane ((alpha-TBECH) and rac-(1R,2R)-1,2-dibromo-(4S)-4-((1R)-1,2-dibromoethyl)cyclohexane (beta-TBECH). The two other possible isomers, gamma- and delta-TBECH, appear in the technical mixture when heated at temperatures above 120 degrees C. Careful selection of GC-capillary column length was critical in resolution of the two main diastereoisomers. Column lengths of 60 or 30 m (0.25 microm film thickness) resulted in incomplete separation of the alpha- and beta-isomers, while on a 10 m column, the isomers were baseline separated. The gamma- and delta-isomers could not be resolved on any column length in this study. Increased injector port temperature induced thermal conversion of the alpha- and beta-isomers to gamma- and delta-TBECH. Electron impact ionization (EI) was used to provide specificity because no characteristic ions in the electron capture negative ionization (ECNI) mass spectrum of TBECH were evident. In EI, the dominant ions in the mass spectrum corresponded to a concomitant loss of HBr and Br from the molecular ion; the biggest peak in this ion cluster (m/z 266.9208) was used for quantitation and the second biggest peak (m/z 264.9227) was used for confirmation. Beluga (Delphinapterus leucas) blubber extracts of animals from the Canadian Arctic (n=29) were analyzed using low resolution (LR) MS and high resolution (HR) MS run at a resolving power of 10,000. beta-TBECH was the only isomer observed in the samples and was detected in 17 samples. The LRMS technique appeared to overestimate beta-TBECH concentrations compared to HRMS, suggesting a small interference arose at the nominal mass monitored. This potential interference also led to some false positive and negative values (n=7) based on the expected ion ratio of the quantitation and confirmation ions. Observed concentrations of the beta-isomer as measured by HRMS ranged from 1.1 to 9.3 ng/g (lipid weight).     

Serum concentrations of polybrominated diphenyl ethers (PBDEs) and polybrominated biphenyl (PBB) in the United States population: 2003-2004

Polybrominated diphenyl ethers (PBDEs) and 2,2',4,4',5,5'-hexabromobiphenyl (BB-153) are chemicals known as brominated flame retardants. We have assessed the exposure status of the United States population to PBDEs and BB-153 and explored associations with demographic information, including participants' age, sex, and race/ethnicity. A total of 2,062 serum samples, from participants in the National Health and Nutrition Examination Survey (NHANES) 2003-2004 aged 12 years and older, were analyzed for PBDEs and BB-153; stratified and regression analyses were used to examine levels among demographic groups. The congener with the highest serum concentration was 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) [geometric mean 20.5 ng/g lipid]; followed by 2,2',4,4',5,5'-hexaBDE (BDE-153) [5.7 ng/g lipid]; 2,2',4,4',5-pentaBDE (BDE-99) [5.0 ng/g lipid; a value equal to the highest limit of detection for an individual sample]; 2,2',4,4',6-pentaBDE (BDE-100) [3.9 ng/g lipid]; BB-153 [2.3 ng/g lipid]; and 2,4,4'-triBDE (BDE-28) [1.2 ng/g lipid]. For BDE-47, we observed no significant difference in the least-squares geometric mean (LSGM) by sex, but with age we found both a linear decrease (p = 0.01) and a positive quadratic trend (p = 0.01). Its LSGM, 27.9 ng/lipid, in the 12-19 year olds decreased to 17.2 ng/g lipid in the 40-49 year group, and then curved upward to 20.4 ng/g lipid in the > or =60 years olds. Mexican Americans had the highest LSGM of BDE-47 (24.5 ng/g lipid), which was significantly higher than that of non-Hispanic whites (19.7 ng/g lipid, p = 0.01). Adults 60 years and older were twice as likely as adults 20-59 years old to have a serum BDE-47 concentration above the 95th percentile (p = 0.02).These data provide needed exposure assessment data for public health decisions.     

Dietary accumulation efficiencies and biotransformation of polybrominated diphenyl ethers in farmed Atlantic salmon (Salmo salar).

The consumer safety of farm-raised salmon could be improved by determining the transfer efficiency of hazardous pollutants from fish feed to the salmon. A controlled feeding trial for 30 weeks was carried out to investigate the transfer of polybrominated diphenyl ethers (PBDEs) in Atlantic salmon (Salmo salar). Using three feed concentrations, an average of 95% of the total PBDE content of feed accumulated in whole salmon. Skinned fillet accumulated 42-59% of the PBDE intake. Equal partitioning according to the lipid content of the tissue was demonstrated. The formation of less brominated PBDEs via preferential debromination from the meta-position was thought to explain the exceptional accumulation efficiencies of BDE 47, BDE 66, BDE 75, BDE 119 and BDE 183 that were either >100% or else increasing with the exposure dose. Monitoring of a larger number of PBDE congeners is recommended to verify the biotransformation routes. The PBDE concentration in salmon of different ages, fed on a known concentration of PBDEs in fish feed, could be predicted by using the accumulation efficiencies determined in this study.     

Particle-phase dry deposition and air-soil gas-exchange of polybrominated diphenyl ethers (PBDEs) in Izmir, Turkey

The particle-phase dry deposition and soil-air gas-exchange of polybrominated diphenyl ethers (PBDEs) were measured in Izmir, Turkey. Relative contributions of different deposition mechanisms (dry particle, dry gas, and wet deposition) were also determined. BDE-209 was the dominating congener in all types of samples (air, deposition, and soil). Average dry deposition fluxes of total PBDEs (sigma7PBDE) for suburban and urban sites were 67.6 and 128.8 ng m(-2) day(-1), respectively. Particulate dry deposition velocities ranged from 11.5 (BDE-28) to 3.9 cm s(-1) (BDE-209) for suburban sites and 7.8 (BDE-28) to 2.8 cm s(-1) (BDE-154) for urban sites with an overall average of 5.8 +/- 3.7 cm s(-1). The highest sigma7PBDE concentration (2.84 x 10(6) ng kg(-1) dry wt) was found around an electronic factory among the 13 soil samples collected from different sites. The concentration in a bag filter dust from a steel plant was also high (2.05 x 10(5) ng kg(-1)), indicating that these industries are significant PBDE sources. Calculated net soil-air gas exchange flux of sigma7PBDE ranged from 11.8 (urban) to 23.4 (industrial) ng m(-2) day(-1) in summer, while in winter it ranged from 3.2 (urban) to 11.6 (suburban) ng m(-2) day(-1). All congeners were deposited at all three sites in winter and summer. It was estimated that the wet deposition also contributes significantly to the total PBDE deposition to soil. Dry particle, wet, and gas deposition contribute 60, 32, and 8%, respectively, to annual PBDE flux to the suburban soil.     

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.     

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.     

Latitudinal fractionation of polybrominated diphenyl ethers and polychlorinated biphenyls in frogs (Rana temporaria)

The flame retardant polybrominated diphenyl ethers (PBDEs) have become ubiquitous environmental pollutants. The environmental distribution of PBDEs is much less studied than that of the polychlorinated biphenyls (PCBs). To compare the environmental fate of the PCBs with their partial substitute, the PBDEs, common frogs (Rana temporaria)were collected along a approximately 1,500-km-long latitudinal gradient of the Scandinavian Peninsula and their livers analyzed for PCBs and PBDEs. Mean concentrations of total PCBs and BDE47 ranged from 9200 to 92 900 and 30 to 120 ng kg(-1) fresh weight, respectively, whereas BDE99 was detected in less than 50% of the frogs. PCB concentrations were higher than that of the PBDEs, and the differences decreased in the northern latitudes. Moreover, the pollutant concentrations in frog livers were negative functions of latitude. The observed scatter and regression slopes imply several influencing factors (such as habitat, exposure route, uptake, metabolism, excretion, etc.) and indicate release events instead of the grasshopper effect Biological variables such as gender, age, body size, and lipid content did not influence pollutant concentrations in the frog livers. The total PCB and BDE47 concentrations in frogs were highly correlated. Hence, their environmental fate is analogous and our results highlight the need to examine the potential role of xenobiotics on amphibian populations.     

Effects of river flooding on polybrominated diphenyl ether (PBDE) levels in cows' milk, soil, and grass

The first investigation into PBDE levels in food produced from flood-prone land on industrial river catchments was conducted. In August 2008 samples of cows' milk, along with grass and soil were taken from 5 pairs of flood-prone and control farms on the River Trent (Central UK). The sum of 7 BDE congeners (28, 47, 99, 100, 153, 154, and 183) was calculated. Higher PBDE levels occurred in soil on flood-prone compared to control farms (median 770 vs 280 ng/kg dry weight). These higher levels were not reflected in the grass samples indicating that PBDE contamination on soils is not transferred efficiently to grass. This observation alongside the fact that cows on flood-prone farms spend time on non-flood-prone land and are fed substantial quantities of commercial feed are reasons why higher PBDE levels were not found in milk from flood-prone farms (median 300 vs 250 ng/kg fat weight). Similar BDE47/BDE99 ratios were observed in soil and grass samples compared to the PBDE product commonly used in the UK, indicating few differences in source-pathway transfer efficiencies between congeners. The BDE47/BDE99 ratio in the milk samples was greater than those in the grass and feed indicating differential food to milk transfer efficiencies between congeners.     

Comparison of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in Lake Michigan salmonids

Polybrominated diphenyl ethers (PBDEs) have been used extensively over the past two decades as flame retardants in most types of polymers. Many measurements of PBDEs in various environmental matrices from Sweden, Holland, Japan, and elsewhere have been reported, but few measurements are available for North America. PBDEs in 21 coho and chinook salmon taken from Lake Michigan tributaries in 1996 were measured for this study. The salmon samples were extracted and initially analyzed for polychlorinated biphenyl (PCB) congeners. It was demonstrated for these samples that the same extract fraction contains PBDEs. Six PBDE congeners were observed in all 21 samples, and the rank order of concentration of these congeners was similar to that in commercial mixtures of PBDEs. The average concentration across all samples of the sum of PBDE congeners was 80.1 ng/g of wet weight or 2,440 ng/g of lipid. This is much less than the average sum PCB concentration (1,450 ng/g of wet weight; 43,100 ng/g of lipid). However, the average concentration of the most abundant PBDE congener (IUPAC BDE-49: 52.1 ng/g wet, 1,590 ng/g of lipid) was about one-third of the average concentration of the most abundant PCB congener (IUPAC CB-153: 149 ng/g wet, 4,550 ng/g of lipid). On the basis of an extensive literature survey, the concentrations of PBDEs reported here are among the highest in the world for salmon in open waters. The concentrations of PBDEs and PCBs are both correlated with fish length and mass, but not with lipid content. The concentrations of PBDEs and PCBs are highly correlated in individual fish, implying that PBDEs are as prevalent as PCBs in Lake Michigan.     

Temporal trends of polybrominated diphenyl ethers and hexabromocyclododecane in milk from Stockholm mothers, 1980-2004

Environmental and human exposures to brominated flame retardants (BFR) have been of emerging concern since some BFR are persistent and bioaccumulative compounds. Among those, polybrominated diphenyl ethers (PBDE) have frequently been reported in low to high ng/g concentrations in human blood around the world while hexabromocyclododecane (HBCDD) only occasionally has been reported and then in the low ppb concentrations in human blood. The present study concerns PBDE congener and HBCDD concentrations in human milk from Stockholm from 1980 to 2004. HBCDD concentrations has increased four to five times since 1980 until 2002 but seems to have stabilized at this concentration in the last years (2003/04). Similarly, BDE-153 has continued to increase at least to 2001, after which it has stabilized in the mother's milk. Other PBDE congeners with four to five bromine substituents peaked 5 years earlier (1995) and are all decreasing. DecaBDE (BDE-209) is not a suitable biomarker for time trend studies according to the present results, showing no changes over time. This is likely due to its short apparent half-life in humans and poor transfer from blood to milk.     

Genotoxicity of several polybrominated diphenyl ethers (PBDEs) and hydroxylated PBDEs, and their mechanisms of toxicity

Polybrominated diphenyl ethers (PBDEs) have been extensively utilized as flame retardants, and recently there has been concern about potential adverse effects in humans and wildlife. Their hydroxylated analogs (OH-BDEs) have received increasing attention due to their potential for endocrine and neurological toxicities. However, the potentials and mechanisms of genotoxicity of these brominated compounds have scarcely been investigated. In the present study, genotoxicity of tetra-BDEs, penta BDE, octa-BDE, deca-BDE, and tetra-OH-BDEs were investigated by use of chicken DT40 cell lines including wild-type cells and a panel of mutant cell lines deficient in DNA repair pathways. Tetra-BDEs have greater genotoxic potential than do the other BDEs tested. OH-tetra-BDEs were more genotoxic than tetra-BDEs. DT40 cells, deficient in base excision repair (Polβ(-/-)) and translesion DNA synthesis (REV3(-/-)) pathways, were hypersensitive to the genotoxic effects of tetra-BDEs and OH-tetra-BDEs. The observation of chromosomal aberrations and gamma-H2AX assay confirmed that the studied brominated compounds caused double strand breaks. Pretreatment with N-acetyl-l-cysteine (NAC) significantly rescued the Polβ(-/-) and REV3(-/-) mutants, which is consistent with the hypothesis that PBDEs and OH-BDEs cause DNA damage mediated through reactive oxygen species (ROS). Some tetra-BDEs and OH-tetra-BDEs caused base damage through ROS leading to replication blockage and subsequent chromosomal breaks.     

Tris(2,3-dibromopropyl) isocyanurate, hexabromocyclododecanes, and polybrominated diphenyl ethers in mollusks from Chinese Bohai Sea

A novel brominated flame retardant (BFR), tris(2,3-dibromopropyl) isocyanurate (TBC), as well as hexabromocyclododecanes (HBCDs) and polybrominated diphenyl ethers (PBDEs), were analyzed in 11 species of mollusks collected from nine coastal cities around the Chinese Bohai Sea in 2009 and 2010. The detection frequencies were 100%, 99%, and 77% for PBDEs, HBCDs, and TBC, respectively. Concentrations of ∑HBCDs ranged from below detection limit (nd) to 28.8 ng g(-1) on a dry weight (dw) basis, followed by ∑(12)PBDE (0.01-20.4 ng g(-1) dw) and TBC (nd-12.1 ng g(-1) dw). Statistically significant linear correlations were found among the three BFRs. Positive correlations were found between BFRs concentrations and lipid content in mollusks. The concentrations tend to decrease with increasing trophic levels of the mollusks, implying trophic dilution rather than biomagnifications of the BFRs in the aquatic food chains of the sampling area. Among the 11 mollusks species, Mytilus edulis showed higher bioaccumulation capability than others and was therefore considered to be an appropriate bioindicator of contamination by the BFRs in the Chinese Bohai Sea, in agreement with its previous selection for the biomonitoring of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). A dramatic decrease in PBDE concentrations in mollusks of the area was found for the time period from 2003 to 2010, with a half-life of only 2.3 ± 1.7 years, reflecting a rapid response of mollusks to the change in pollution of the marine environment.     

Identification of hydroxylated and methoxylated polybrominated diphenyl ethers in Baltic Sea salmon (Salmo salar) blood

Methoxylated and hydroxylated polybrominated diphenyl ethers (MeO-PBDEs and OH-PBDEs) have recently been reported to be present in wildlife from Northern Europe. The structures of a majority of these compounds have however been unknown. In the present study, nine OH-PBDEs and six MeO-PBDEs were identified in Baltic Sea salmon (Salmo salar) blood. All OH- and MeO-PBDEs identified were substituted with four or five bromines, and five of these had one chlorine substituent. Fourteen of the OH- and MeO-PBDEs have the methoxy or hydroxy group substituted in the ortho position to the diphenyl ether bond. Identification was done by comparison of relative retention times of authentic reference standards with compounds present in salmon plasma on two gas chromatographic columns of different polarities. The identification was supported by comparisons of full-scan mass spectrometric data: electron ionization (EI) and electron capture negative ionization (ECNI). Nine of the 15 OH- and MeO-PBDEs identified have not previously been reported to occur in the environment. The structures of several identified OH- and MeO-PBDEs support natural origin. However, at least one of the OH-PBDEs may be a hydroxylated metabolite of anthropogenic polybrominated diphenyl ether (PBDE).     

Evidence for bioavailability of Au nanoparticles from soil and biodistribution within earthworms (Eisenia fetida)

Because Au nanoparticles (NPs) are resistant to oxidative dissolution and are easily detected, they have been used as stable probes for the behavior of nanomaterials within biological systems. Previous studies provide somewhat limited evidence for bioavailability of Au NPs in food webs, because the spatial distribution within tissues and the speciation of Au was not determined. In this study, we provide multiple lines of evidence, including orthogonal microspectroscopic techniques, as well as evidence from biological responses, that Au NPs are bioavailable from soil to a model detritivore (Eisenia fetida). We also present limited evidence that Au NPs may cause adverse effects on earthworm reproduction. This is perhaps the first study to demonstrate that Au NPs can be taken up by detritivores from soil and distributed among tissues. We found that primary particle size (20 or 55 nm) did not consistently influence accumulated concentrations on a mass concentration basis; however, on a particle number basis the 20 nm particles were more bioavailable. Differences in bioavailability between the treatments may have been explained by aggregation behavior in pore water. The results suggest that nanoparticles present in soil from activities such as biosolids application have the potential to enter terrestrial food webs.     

Concentrations of polybrominated diphenyl ethers in air and soil on a rural-urban transect across a major UK conurbation

Polybrominated diphenyl ethers (PBDEs) were measured in air (using PUF disk passive samplers) and soil samples taken at approximately monthly intervals over 1 year at 10 locations on a transect across the West Midlands of the UK. Concentrations in air are consistent with those detected elsewhere in Europe and the Great Lakes basin. Concentrations in soil fall within the range reported for rural woodland and grassland soils in the UK and Norway. In both air and soil, concentrations clearly decrease with increasing distance from the city center, supporting the existence of an urban "pulse", indicating the West Midlands conurbation to be a source of PBDEs to the wider environment. Examination of seasonal trends revealed no evidence of a "spring pulse" in concentrations in air, with no summer peak in concentrations in air observed for 70% of sites. The PBDE congener pattern in air differs from that in soil, with ratios of congeners 47:99 higher in air than in soil. It is hypothesized that PBDEs volatilize from treated products indoors, before ventilating outdoors, where congener 99 undergoes preferential atmospheric deposition and accumulation in soil.     

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) in the abiotic environment: surface water and precipitation from Ontario, Canada

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have been identified as metabolites of PBDEs, and also as compounds of natural origin in the marine environment; however, there has only been very limited study of their presence in the abiotic environment. In the present study, OH-PBDEs were determined in samples of surface water and precipitation (rain and snow) collected from sites in Ontario, Canada. OH-PBDEs were detected in all the samples analyzed, although half of the observed peaks did not correspond to any of the 18 authentic standards available. Fluxes of sigmaOH-PBDEs ranged from 3.5 to 190 pg/m2 in snow and from 15 to 170 pg/m2/day in rain, and those were higher at three of the southern Ontario locations relative to a single northern remote site. Concentrations of sigmaOH-PBDEs ranged from 2.2 to 70 pg/L in water and from < 1 to 420 pg/g in particulate organic carbon (POC), and higher values were found near sewage treatment plant (STP) outfalls in Lake Ontario. Partition coefficients (log K(oc)) for OH-PBDEs ranged from 4.0 to 5.1. The results in this study suggest that OH-PBDEs are ubiquitous in the abiotic environment and most likely are produced through reaction of PBDEs with atmospheric OH radicals. As well, they may be present in surface waters near STPs due to oxidation of PBDEs and inflows from metabolism by humans and animals.     

Levels and temporal trends (1988-1999) of polybrominated diphenyl ethers in beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary, Canada

Polybrominated diphenyl ethers (PBDEs) were determined in blubber samples of 54 stranded adult beluga whales (Delphinapterus leucas) collected between 1988 and 1999 in the St. Lawrence Estuary (SLE), Quebec, Canada. Summed concentrations of 10 PBDE congeners (sigmaPBDEs) measured in beluga samples varied between 20 and almost 1000 ng/g wet weight. According to the PBDE concentrations in marine mammals reported in the scientific literature, SLE belugas appear to be relatively lightly contaminated. Only a few predominant congeners (namely, PBDE-47, -99, and -100) represent on average more than 75% of sigmaPBDEs in SLE belugas. The accumulation of sigmaPBDEs in both male and female belugas showed significant exponential increase throughout the 1988-1999 time period. The time necessary for beluga to double their blubber concentration of the most prevalent PBDE congeners was no longer than 3 years. The PBDE temporal changes reported in this study are generally faster but in agreement with the trend observed in other organisms collected in Canada, such as lake trout (Salvelinus namaycush) from the Great Lakes, ringed seal (Phoca hispida), and beluga whale from the Canadian Arctic. Some changes in the pattern of PBDEs in belugas were also observed during the time period investigated. The recent and important increase of PBDE levels in SLE belugas could explain the unexpected lack of statistical difference in PBDE contamination between males and females. This suggests that to date PBDEs tend to be accumulated by both male and female belugas, masking the elimination of PBDEs by females through post-natal transfer to their offspring. This study confirms that the growing use of PBDEs as flame retardants has resulted in rising contamination of Canadian aquatic environments. Additional studies are needed to assess the toxicological implications of the PBDE tissue levels found in SLE belugas.     

Fate, partitioning, and mass loading of polybrominated diphenyl ethers (PBDEs) during the treatment processing of municipal sewage

Sewage treatment plant (STP) effluents are likely a major source of contamination for PBDEs, especially in the receiving water bodies of local aquatic environments surrounding the location of these discharges. Congeners of the pentaBDE mixture, 2,2,',4,4'-tetrabromodiphenyl ether (BDE47), 2,2,',4,4',5-pentabromodiphenyl ether (BDE99), 2,2,',4,4',6-pentabromodiphenyl ether (BDE100), 2,2,',4,4',5,5'-hexabromodiphenyl ether (BDE153), and 2,2,',4,4',5,6'-hexabromodiphenyl ether (BDE154), are of great environmental concern in North America due to their persistence, potential for bioaccumulation, and >97% use of the global production of the mixture in the region. Detailed characterization of the distribution of eight PBDE congeners (2,4,4'-tribromoDE (BDE28) and BDE47, 99, 100, 138, 153, 154, and 183) was carried out at five sites along the treatment process at an activated sludge-type secondary treatment municipal STP facility. PentaBDE mixture congeners, sigma5PBDE (sum of BDE47, 99, 100, 153, and 154) accounted for >98% of the total (sigma 8) PBDE concentration at all sites, with over 80% of the composition being BDE47 and BDE99. Presence of dissolved organic matter affected the mobility of PBDEs during the initial stages of the treatment process. About 9% of the influent mass of sigma5PBDE to the facility is estimated to be discharged into the Little River (leading to the Detroit River) with the final effluent, resulting in an estimated mass loading of approximately 0.7 kg/year. The total mass loading of sigma5PBDE to the Detroit River is expected to be much larger as effluent from this facility accounts for <10% of the total STP discharges to the river.     

Dietary intake estimations of polybrominated diphenyl ethers (PBDEs) based on a total diet study in Osaka,Japan

This study presents the results of a total diet study performed for estimating the dietary intake of polybrominated diphenyl ethers (PBDEs) in Osaka, Japan. The concentrations of 36 PBDEs were measured in samples from 14 food groups (Groups I–XIV). PBDEs were detected only in Groups IV (oils and fats), V (legumes and their products), X (fish, shellfish, and their products), and XI (meat and eggs) at concentrations of 1.8, 0.03, 0.48, and 0.01 ng g^?1, respectively. For an average person, the lower bound dietary intakes of penta- and deca-formulations were estimated to be 46 and 21 ng day^?1, respectively. A high proportion of the decabrominated congener (DeBDE-209) was observed in Group IV. To confirm the presence of DeBDE-209 in vegetable oils, an additional analysis was performed using 18 vegetable oil samples. Of these, seven contained ng g^?1 levels of DeBDE-209.     

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.