Bioaccumulation of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in wild aquatic species from an electronic waste (e-waste) recycling site in South China

Water and several wild aquatic species including Chinese mysterysnail, prawn, fish, and water snake were collected from a reservoir surrounded by several e-waste recycling workshops in South China. The samples were examined to investigate the levels and bioaccumulation extent of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) released from electronic waste (e-waste) which was processed by crude recycling method. Elevated levels of PBDEs [52.7 to 1702 ng/g wet weight (ww)] and PCBs (20.2-25958 ng/g ww) were found in the collected biota species compared to that in the reference samples (13.0-20.5 ng/g ww for PBDEs and 75.4-82.8 ng/g ww for PCBs). log BAF (bioaccumulation factor) ranged from 2.9 to 5.3 for PBDEs and from 1.2 to 8.4 for PCBs, depending on congeners and species. The relationship between log BAFs and log K(OW) (octanol-water partition coefficient) can be adequately described by species-specific parabolic models wherein log BAFs generally increased at log K(OW)<7 then decreased with further increasing log K(OW) both for PBDEs and PCBs. The exceptions were for Chinese mysterysnail and prawn, in which the log BAFs showed a positive linear correlation with log K(OW) for PBDEs. Some PBDE and PCB congeners showed BAF values declining from the general trend predicted by K(OW), largely attributing to metabolism of these congeners in species sampled.     

Brominated flame retardants (BFRs) in breast milk and associated health risks to nursing infants in Northern Tanzania

The main aim of this study was to assess brominated flame retardants (BFRs) in breast milk in the Northern parts of Tanzania. Ninety-five colostrum samples from healthy, primiparous mothers at Mount Meru Regional Referral Hospital (MMRRH), Arusha Tanzania, were analyzed for polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), hexabromobenzene (HBB), (2,3-dibromopropyl) (2,4,6-tribromophenyl) ether (DPTE), pentabromoethylbenzene (PBEB) and 2,3,4,5,6-pentabromotoluene (PBT). The Ʃ₇PBDE (BDE 28, 47, 99, 100, 153, 154, 183) ranged from below level of detection (< LOD) to 785 ng/g lipid weight (lw). BDE 47, 99, 100 and 153 were the dominating congeners, suggesting recent and ongoing exposure to banned, commercial PentaBDE mixture. A multiple linear regression model revealed that mothers eating clay soil/Pemba during pregnancy had significantly higher levels of BDE 47, 99, 100 and 153 in their breast milk than mothers who did not eat clay soil/Pemba. Infant birth weight and birth length were significantly correlated with the levels of BDE 47, 99, 100 and 153. The estimated daily intake (ng/kg body weight/day) of BDE 47 and 99 exceeded the US EPA Reference doses (RfD) in four and eight mothers, respectively, suggesting a potential health risk to the nursing infants.     

Metabolism in the toxicokinetics and fate of brominated flame retardants--a review

Several classes of brominated flame retardants (BFRs), namely polybrominated biphenyls (PBBs), polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCCD), bis(2,4,6-tribromophenoxy)ethane (BTBPE), and tris(2,3-dibromopropyl)phosphate (Tris), have been identified as environmental contaminants. PBDEs, TBBPA, and HBCCD are of particular concern due to increasing environmental concentrations and their ubiquitous presence in the tissues of humans and wildlife from Europe, Japan, and North America. Regardless, the toxicokinetics, in particular metabolism, of BFRs has received little attention. The present review summarizes the current state of knowledge of BFR metabolism, which is an important factor in determining the bioaccumulation, fate, toxicokinetics, and potential toxicity of BFRs in exposed organisms. Of the minimal metabolism research done, BFRs have been shown to be susceptible to several metabolic processes including oxidative debromination, reductive debromination, oxidative CYP enzyme-mediated biotransformation, and/or Phase II conjugation (glucuronidation and sulfation).However, substantially more research on metabolism is necessary to fully assess BFR fate, uptake and elimination kinetics, metabolic pathways, inter-species differences, the influence of congener structure, and the potential health risks to exposed organisms.     

Tetrabromobisphenol-A, hexabromocyclododecane and its degradation products in UK human milk: relationship to external exposure

Tetrabromobisphenol-A (TBBP-A), hexabromocyclododecane (HBCD) and its degradation products were determined in 34 human milk samples from Birmingham, UK. TBBP-A was detected in 36% of samples (average=0.06 ng g(-1) lw), with HBCDs detected in all samples (average ΣHBCDs=5.95 ng g(-1) lw). α-HBCD comprised 62-95% ΣHBCDs while β- and γ-HBCD constituted 2-18% and 3-33% respectively. Enantioselective enrichment of (-)-α-HBCD (average enantiomer fraction=0.29) was observed indicating potential enantioselectivity associated with HBCD absorption, metabolism and/or excretion. The degradation products pentabromocyclododecenes (average=0.04 ng g(-1) lw; n=9) and tetrabromocyclododecadienes (average=0.15 ng g(-1) lw; n=25) were detected for the first time in human tissues. Average exposures of a nursing infant to ΣHBCDs and TBBP-A (35 and 1 ng kg(-1) bw day(-1) respectively) via breast milk exceeded upper-bound dietary intakes of both UK adults and toddlers. Using a simple pharmacokinetic model, intakes of UK adults via inhalation, diet and dust ingestion were converted to predicted body burdens. Predictions compared well with those observed for HBCDs but observed body burdens of TBBP-A exceeded predictions. This may indicate the human half-life of TBBP-A is greater than observed previously, that intakes may be underestimated, or that concentrations reported here reflect recent elevated episodic exposure.     

Halogenated flame retardants in home-produced eggs from an electronic waste recycling region in South China: Levels,composition profiles,and human dietary exposure assessment

Three regulated halogenated flame retardants (HFRs), i.e., polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs) and hexabromocyclododecanes (HBCDs), and several alternative HFRs (AHFRs) including Dechlorane Plus (DP), decabromodiphenyl ethane (DBDPE), and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), were investigated in the home-produced eggs from three recycling sites and a reference site in an electronic waste (e-waste) recycling region, South China. Mean levels of HFRs in eggs from the recycling sites ranged 2640–14 100, 700–1620, 44–350, and 720–3920 ng/g lipid weight for ∑PBDEs, ∑PBBs, ∑HBCDs, and ∑AHFRs, respectively, which were one to two orders of magnitude higher than those examined in the reference site. PBDEs were the predominant HFR in those eggs, with contributions > 50% to the total HFRs; followed by PBBs and the AHFRs (contributing 14–22% in average). The α-HBCD was the predominant diastereoisomers of HBCDs, with preferential enrichment of the (−)-enantiomer in most of the eggs; but no significant stereoselective enrichment of the DP isomers was observed in these eggs. The average estimated daily intakes (EDIs) of PBDEs, PBBs, HBCDs, and the AHFRs via eggs from the recycling sites ranged 4200–20 000, 1120–2440, 80–490, and 970–4530 ng/day, respectively, which were one to two orders of magnitude higher than those reported from other parts of the world. The potential adverse effects of these HFRs to human health in the e-waste sites should be further investigated. This is the first report on the isomer compositions of DP and the chiral signatures of HBCDs in hen eggs.     

Tissue-specific accumulation of polybrominated diphenyl ethers (PBDEs) including Deca-BDE and hexabromocyclododecanes (HBCDs) in harbor seals from the northwest Atlantic

Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) are widely used flame retardants that enter coastal waters from multiple sources and biomagnify in marine food webs. PBDEs have been detected at relatively high concentrations in harbor seals, apex predators in the northwest Atlantic. Whereas tri- to hexa-BDEs readily biomagnified from prey fishes to seal blubber, Deca-BDE (BDE-209) did not biomagnify in blubber. To explore tissue-specific differences in the accumulation/biomagnification of BFRs, we analyzed tri- to Deca-BDES in liver of 56 harbor seals (6 adult males, 50 pups), and compared hepatic concentrations and biomagnification potential with those in blubber. HBCDs were analyzed in seal liver and blubber to enable similar comparisons. Hepatic ΣPBDE (tri- to Octa-BDE) concentrations (range 35–19,547 ng/g lipid weight, lw) were similar to blubber concentrations, while α-HBCD levels in seal liver (range 2–279 ng/g lw) were significantly higher than levels in blubber. Tissue distribution of PBDEs and α-HBCD varied significantly by age and, surprisingly, by gender among the pups. Biomagnification of α-HBCD from fish to seal liver and blubber was negligible to low, implying that harbor seals can metabolize this persistent isomer. Similar to the patterns in blubber, tri- through hexa-BDEs were highly biomagnified from fish to seal liver. In contrast, BDE-209 concentrations in liver were up to five times higher than those in blubber, which is consistent with observations that BDE-209 migrates to perfused tissues such as the liver in biota. Although detection frequency was low, BDE-209 levels in seal liver were up to ten times higher than those in their prey fish, suggesting that the accumulation/biomagnification of Deca-BDE in marine food webs is tissue-specific. As BDE-209 is the dominant PBDE found in marine sediments, its biomagnification in marine ecosystems is of concern.     

Causes of variability in concentrations and diastereomer patterns of hexabromocyclododecanes in indoor dust

The temporal evolution of concentrations of α-, β-, and γ-hexabromocyclododecanes (HBCDs), and pentabromocyclododecenes (PBCDs — degradation products of HBCDs) was studied in separate aliquots of a well-homogenized indoor dust sample. These were: (a) exposed to natural light, and (b) kept in the dark. Results revealed a rapid photolytically-mediated shift from γ-HBCD to α-HBCD that was complete after 1 week of exposure, and a slower degradative loss of HBCDs via elimination of HBr. Under the specific conditions studied in this experiment, calculated half-lives (t_1/2) showed the decay in ΣHBCDs concentration was faster in light-exposed samples (t_1/2 = 12 weeks), than in light-shielded dust (t_1/2 = 26 weeks). Within-room spatial and temporal variability in concentrations and diastereomer patterns were studied in six and three rooms respectively. While in some rooms, little variability was detected, in others it was substantial. In one room, concentrations of ΣHBCDs and the relative abundance of γ-HBCD declined dramatically with increasing distance from a TV. The same TV appears to have influenced strongly the temporal variation in that room; with higher concentrations observed in its presence and when the TV was moved closer to the area sampled. Significant negative correlation was observed in one room between concentrations of ΣHBCDs and dust loading (g dust m^? 2 floor), implying “dilution” occurs at higher dust loadings.     

Trends in the levels of halogenated flame retardants in the Great Lakes atmosphere over the period 2005–2013

Air (vapor and particle phase) samples were collected every 12 days at five sites near the North American Great Lakes from 1 January 2005 to 31 December 2013 as a part of the Integrated Atmospheric Deposition Network (IADN). The concentrations of 35 polybrominated diphenyl ethers (PBDEs) and eight other halogenated flame retardants were measured in each of the ~ 1,300 samples. The levels of almost all of these flame retardants, except for pentabromoethylbenzene (PBEB), hexabromobenzene (HBB), and Dechlorane Plus (DP), were significantly higher in Chicago, Cleveland, and Sturgeon Point. The concentrations of PBEB and HBB were relatively high at Eagle Harbor and Sturgeon Point, respectively, and the concentrations of DP were relatively high at Cleveland and Sturgeon Point, the two sites closest to this compound's production site. The data were analyzed using a multiple linear regression model to determine significant temporal trends in these atmospheric concentrations. The concentrations of PBDEs were decreasing at the urban sites, Chicago and Cleveland, but were generally unchanging at the remote sites, Sleeping Bear Dunes and Eagle Harbor. The concentrations of PBEB were decreasing at almost all sites except for Eagle Harbor, where the highest PBEB levels were observed. HBB concentrations were decreasing at all sites except for Sturgeon Point, where HBB levels were the highest. DP concentrations were increasing with doubling times of 3–9 years at all sites except those closest to its source (Cleveland and Sturgeon Point). The levels of 1,2-bis(2,4,6-tribromophenoxy)ethane (TBE) were unchanging at the urban sites, Chicago and Cleveland, but decreasing at the suburban and remote sites, Sturgeon Point and Eagle Harbor. The atmospheric concentrations of 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EHTBB) and bis(2-ethylhexyl)-tetrabromophthalate (BEHTBP) were increasing at almost every site with doubling times of 3–6 years.     

Biota-sediment accumulation factors for Dechlorane Plus in bottom fish from an electronic waste recycling site, South China

Biota-sediment accumulation factors (BSAFs) for Dechlorane Plus (DP), a highly chlorinated flame retardant, were determined in three bottom fish species, i.e., crucian carp, mud carp, and northern snakehead from an electronic waste recycling site in South China. The average BSAFs are 0.007, 0.01, and 0.06 for syn-DP, and 0.003, 0.025, and 0.001 for anti-DP in crucian carp, mud carp, and northern snakehead, respectively, suggesting low bioaccumulation potential of DP isomers in these fish. However, the bioaccumulation factors (BAFs) determined previously in the same sample set indicated that both DP isomers were highly bioaccumulative (BAFs>5000) in most of the samples. This implies that BSAF values may be inherently inconsistent affecting their reliability as a bioaccumulation indicator. The BSAFs for DP isomers are two orders of magnitude lower than those (average of 0.43-2.28) for extremely hydrophobic polychlorinated biphenyls (CBs 199, 203, 207 and 208), but are comparable to those (average of 0.0001-0.009) for decabromodiphenyl ether (BDE 209) determined in the same sample set. Despite of the different chemical structures of the three compound classes, significantly negative correlations between logarithm of octanol-water partition coefficients (log K(OW)s) and BSAFs of these chemicals were found, indicating that hydrophobicity is one of the key factors influencing the bioaccumulation of these compounds.     

Human exposure to PCBs, PBDEs and HBCDs in Ghana: Temporal variation, sources of exposure and estimation of daily intakes by infants

Human exposure to polychlorinated biphenyls (PCBs) and brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) was evaluated in Ghana using breast milk samples collected in 2004 and 2009. Mean levels and ranges of PBDEs (4.5; 0.86-18 ng/g lw) and PCBs (62; 15-160 ng/g lw) observed in the present study were unexpectedly high, in spite of the fact that Ghana is a non-industrialized country when compared with many of the Asian and European countries. Significant increases were found in the concentrations of PCBs and PBDEs over the years, while no significant increase was observed for HBCDs. Estimated hazard quotient (HQ) showed that all the mothers had HQ values exceeding the threshold of 1 for PCBs, indicating potential health risk for their children. PCBs in dirty oils and obsolete equipment should be of concern as potential sources in Ghana, and e-waste recycling with little or no experience in safe handling could be a threat to this sub-region noted for unregulated disposal of e-waste. The results may point towards an increase in trends in human milk in Ghana, especially in the larger cities but further analysis would be required to confirm this upward trend in levels. This is the first study to report BFRs in human breast milk from Africa, and undoubtedly from Ghana.     

Personal exposure to HBCDs and its degradation products via ingestion of indoor dust

Personal exposures via ingestion of indoor dust to α-, β-, and γ-hexabromocyclododecanes (HBCDs) and the degradation products (pentabromocyclododecenes (PBCDs) and tetrabromocyclododecadienes (TBCDs)) were estimated for 21 UK adults. Under an average dust ingestion scenario, personal exposures ranged from 4.5 to 1851 ng ΣHBCDs day^? 1; while the range under a high dust ingestion scenario was 11 to 4630 ng ΣHBCDs day^? 1. On average, personal exposure to ΣHBCDs via dust ingestion in this study was 35% α-, 11% β-, and 54% γ-HBCD. However, while exposure to β-HBCD (4–18% of ΣHBCDs) was relatively consistent with the proportion of this diastereomer in the HBCD commercial formulation; exposures to α- and γ-isomers (11–58% and 29–82% of ΣHBCDs respectively) showed substantial variation from the commercial formulation pattern. Personal exposures to ΣTBCDs (median = 0.2 ng day^? 1 under an average dust ingestion scenario) and ΣPBCDs (1.4 ng day^? 1) were significantly lower (p < 0.05) than for ΣHBCDs (48 ng day^? 1). Despite this, the exposure of one participant to ΣPBCDs exceeded the exposure to ΣHBCDs received by 85% of the other participants. On average, house dust provided the major contribution to personal exposure via dust ingestion to all target compounds due to the large time fraction spent in houses. In contrast, although participants spent less time in cars than in offices, car dust makes a higher average contribution (17%) to ΣHBCDs exposure than office dust (13%).     

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

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

Bioaccumulation of PCDD/Fs,PCBs and PBDEs by earthworms in field soils of an E-waste dismantling area in China

A total of 60 paired samples of earthworm, corresponding soil and wormcast were collected to investigate the bioaccumulation tendency of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in earthworms from a typical E-waste dismantling area in east China. Significant correlations were observed for the total concentrations among different matrix types except for PCDD/Fs in soil and earthworm. The bioaccumulation tendency showed some differences among the contaminants. Calculated biota–soil accumulation factors (BSAFs) indicated that PCBs and PBDEs had higher bioaccumulation potential compared to PCDD/Fs, which was somewhat different from laboratory studies. The plot of mean BSAFs versus log K_ow values for PCBs and PBDEs was well fitted by a second-order polynomial with the maximum BSAF at approximately log K_ow of 6.5. While for PCDD/Fs, only a slightly decreasing trend was observed with increasing log K_ow. Composition analysis indicated that tetra-, penta- and hexa-halogenated homologs had higher bioaccumulation levels, indicating that medium-halogenated congeners with log K_ow around 6.5 are more easily accumulated by earthworms. Furthermore, the ratios of BDE-47/-99 and BDE-99/-100 showed some discrepancies with the technical products and other biotic species, suggesting different bioaccumulation potential of PBDEs in earthworm.     

Emerging and historical brominated flame retardants in peregrine falcon (Falco peregrinus) eggs from Canada and Spain

Comparisons of brominated flame retardants (BFRs) in the eggs of peregrine falcons (Falco peregrinus) recently collected (2003–2007), are made between Canada (N = 12) and Spain (N = 13). Overall, concentrations of sum (Σ) polybrominated diphenyl ethers (PBDEs; 16 di-deca-BDE congeners) exceeded Σhexabromocyclododecane (HBCD) and were an order of magnitude higher than 2,2′4,4′,5,5′-hexabromobiphenyl (BB-153) > hexachlorocyclopentenyl-dibromocyclooctane (HCBDCO) > 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) > decabromodiphenylethane (DBDPE) > octabromotrimethylphenyllindane (OBIND) > hexabromobenzene (HBB) > bis(2-ethyl-1hexyl)tetrabromophthalate (BEHTBP). This is the first report of detectable HBCDCO and BEHTBP concentrations in biota, and the highest in ovo concentration of ∑ HBCD (14,617 ng/g lw; Montreal, Canada) to date. There were significantly greater egg concentrations of BB-153, ΣHBCD, and ΣPBDE including BDE-153, -99, -100 and -183, in Canadian than Spanish peregrines with a terrestrial diet. HBB, BTBPE, and OBIND were detected in eggs from both countries, but only Canadian peregrine eggs had detectable levels of HCDBCO (25%) and DBDPE (N = 1). The in ovo PBDE congener profile was dominated by BDE-153 > BDE-99 > BDE-47 > BDE-183 > BDE-100 > BDE-209, with the isomeric HBCD pattern being α-HBCD > γ-HBCD (β-HBCD undetected). The Canadian peregrine eggs had lower enantiomeric HBCD values consistent with their higher fractions of (−) α-HBCD, suggesting selective enantiomeric enrichment or that the (+) α-isomer is more readily metabolized and so deposited in the egg through maternal transfer. Continental differences in egg burdens of peregrines are discussed relative to BFR usage patterns and exposure of peregrines on their breeding grounds.     

Brominated flame retardants and polychlorinated biphenyls in fish from the river Scheldt, Belgium

Levels of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), and polychlorinated biphenyls (PCBs) were measured in several fish species originating from the river Scheldt (Belgium). Five sampling locations were chosen in a highly industrialized area along the river, while two ponds in the vicinity of the river served as reference sites. The present study is a follow-up of a survey performed in 2000 which reported extremely high levels of PBDEs and HBCDs in eel (Anguilla anguilla) collected from the same region (Oudenaarde, Flanders). The sum of tri- to hepta-BDE congeners (2270+/-2260 ng/g lipid weight (lw), range 660-11500 ng/g lw) and total HBCDs (4500+/-3000 ng/g lw, range 390-12100 ng/g lw) were one order of magnitude higher than levels usually reported from freshwater systems, indicating the presence of point sources. In most samples, levels of total HBCDs were higher than those of PBDEs, probably due to the high density of factories using HBCD as an additive brominated flame retardant (BFR). The high values of HBCDs were confirmed by both gas- and liquid-chromatography-mass spectrometry. Although BFR levels were between the highest ever reported in freshwater ecosystems, PCBs could be detected at even higher concentrations (16000+/-14300 ng/g lw, range 3900-66600 ng/g lw), being among the highest levels recorded in Belgium. The inter-sampling site variation of PBDEs, HBCDs and PCBs was comparable. All locations presented similar PBDE congener profiles, with BDE 47 being the dominant congener, followed by BDE 100, BDE 99 and BDE 49, probably originating from the former use of the penta-BDE technical mixture. In order to estimate the impact of these point sources on human exposure, we further focussed on eels which showed a considerable decrease in the PBDE and HBCD levels between 2000 and 2006. Due to the wide span in concentrations between the different sampling locations, a variable contribution to the total human exposure through local eel consumption was estimated. The calculated daily intake ranged from 3 ng to 330 ng PBDEs/day for normal eel consumers, but was as high as 9800 ng PBDEs/day for anglers, which may be considered at risk.     

Brominated flame retardants and polychlorinated biphenyls in human breast milk from several locations in India: potential contaminant sources in a municipal dumping site

This study investigated the status of contamination of organohalogen compounds (OCs) such as polychlorinated biphenyls (PCBs) and brominated flame retardant (BFRs), including polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) in human milk samples from several locations in India. The levels of OCs were significantly higher in the milk of mothers living in and near municipal dumping site than other locations indicating that the open dumping sites for municipal wastes act as potential sources of these contaminants in India. The PCB concentrations observed in this study tended to decrease compared to those in the matched locations reported previously, probably due to the restriction of technical PCB usage in India. PBDE levels in human milk were two to three folds lower than those of PCBs in all the sampling locations investigated. Congener profiles of PCBs and PBDEs were different between samples from the dumping site mothers and general populations in other areas suggesting the presence of region-specific sources and pathways. HBCDs were detected in human milk from only two sites, with much lower concentrations and detection frequencies compared to PCBs and PBDEs. When hazard quotients (HQs) of PCBs and PBDEs were estimated for infant health risk, the HQs in some milk samples from the dumping site exceeded the threshold value (HQ > 1) of PCBs, indicating the potential risk for infants in the specific site.     

Brominated flame retardants in the indoor environment — Comparative study of indoor contamination from three countries

Concentrations of more than 20 brominated flame retardants (FRs), including polybrominated diphenyl ethers (PBDEs) and emerging FRs, were measured in air, dust and window wipes from 63 homes in Canada, the Czech Republic and the United States in the spring and summer of 2013. Among the PBDEs, the highest concentrations were generally BDE-209 in all three matrices, followed by Penta-BDEs. Among alternative FRs, EHTBB and BEHTBP were detected at the highest concentrations. DBDPE was also a major alternative FR detected in dust and air. Bromobenzenes were detected at lower levels than PBDEs and other alternative FRs; among the bromobenzenes, HBB and PBEB were the most abundant compounds. In general, FR levels were highest in the US and lowest in the Czech Republic — a geographic trend that reflects the flame retardants' market. No statistically significant differences were detected between bedroom and living room FR concentrations in the same house (n = 10), suggesting that sources of FRs are widespread indoors and mixing between rooms. The concentrations of FRs in air, dust, and window film were significantly correlated, especially for PBDEs. We found a significant relationship between the concentrations in dust and window film and in the gas phase for FRs with log K_OA values < 14, suggesting that equilibrium was reached for these but not compounds with log K_OA values > 14. This hypothesis was confirmed by a large discrepancy between values predicted using a partitioning model and the measured values for FRs with log K_OA values > 14.     

Brominated and chlorinated flame retardants in San Francisco Bay sediments and wildlife

Restrictions on the use of polybrominated diphenyl ethers (PBDEs) have resulted in the use of alternative flame retardants in consumer products to comply with flammability standards. In contrast to PBDEs, information on the occurrence and fate of these alternative compounds in the environment is limited, particularly in the United States. In this study, a survey of flame retardants in San Francisco Bay was conducted to evaluate whether PBDE replacement chemicals and other current use flame retardants were accumulating in the Bay food web. In addition to PBDEs, brominated and chlorinated flame retardants (hexabromocyclododecane (HBCD) and Dechlorane Plus (DP)) were detected in Bay sediments and wildlife. Median concentrations of PBDEs, HBCD, and DP, respectively, were 4.3, 0.3, and 0.2 ng g^− 1 dry weight (dw) in sediments; 1670, < 6.0, and 0.5 ng g^− 1 lipid weight (lw) in white croaker (Genyonemus lineatus); 1860, 6.5, and 1.3 ng g^− 1 lw in shiner surfperch (Cymatogaster aggregata); 5500, 37.4, and 0.9 ng g^− 1 lw in eggs of double-crested cormorant (Phalacrocorax auritus); 770, 7.1, and 0.9 ng g^− 1 lw in harbor seal (Phoca vitulina) adults; and 330, 3.5, and < 0.1 ng g^− 1 lw in harbor seal (P. vitulina) pups. Two additional flame retardants, pentabromoethylbenzene (PBEB) and 1,2-bis(2,4,6 tribromophenoxy)ethane (BTBPE) were detected in sediments but with less frequency and at lower concentrations (median concentrations of 0.01 and 0.02 ng g^− 1 dw, respectively) compared to the other flame retardants. PBEB was also detected in each of the adult harbor seals and in 83% of the pups (median concentrations 0.2 and 0.07 ng g^− 1 lw, respectively). The flame retardants hexabromobenzene (HBB), decabromodiphenyl ethane (DBDPE), bis(2-ethylhexyl) tetrabromophthalate (TBPH), and 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB), were not detected in sediments and BTBPE, HBB and TBB were not detected in wildlife samples. Elevated concentrations of some flame retardants were likely associated with urbanization and Bay hydrodynamics. Compared to other locations, concentrations of PBDEs in Bay wildlife were comparable or higher, while concentrations of the alternatives were generally lower. This study is the first to determine concentrations of PBDE replacement products and other flame retardants in San Francisco Bay, providing some of the first data on the food web occurrence of these flame retardants in a North American urbanized estuary.     

Environmental release and behavior of brominated flame retardants

Recently, environmental problems relating to brominated flame retardants (BFRs) have become a matter of greater concern than ever before, because of the recent marked increase in levels of polybrominated diphenyl ethers (PBDEs) found in human milk in Sweden and North America. The question that arises is whether environmental levels of PBDEs and other BFRs will continue to increase, causing toxic effects to humans. In an attempt to elucidate the current state of the science of BFRs, we review the consumer demand for BFRs (mainly in Japan), the characteristics of waste flame-retarded products, sources of emission, environmental behavior, routes of exposure of humans, temporal trends, and thermal-breakdown products of BFRs. At present, flame-retarded consumer products manufactured 10-20 years ago, when PBDEs were frequently used, are being dumped. The possible major sources of emission of BFRs into the environment are effluent and flue gases from BFR factories and other facilities processing BFRs. With respect to the environmental behavior of BFRs, the lower brominated compounds are, on the whole, predicted to be more volatile, more water soluble, and more bioaccumulative than the higher brominated compounds. The most probable route for exposure of the general human population to PBDEs, especially the lower brominated congeners, is through the diet. The release of BFRs from consumer products treated with these compounds could also lead to human exposure. Temporal trends in PBDE levels in the environment and in humans worldwide seem to vary considerably, depending on the regions or country, with possible reflections of the historic and current use of PBDEs. The environment and the general human population are also exposed to the thermal-breakdown products of PBDEs, such as polybrominated and mixed brominated/chlorinated dibenzo-p-dioxins and dibenzofurans (PBDDs/DFs and mixed PXDDs/DFs).     

Measurement of flame retardants and triclosan in municipal sewage sludge and biosolids

As polybrominated diphenyl ethers (PBDEs) face increasing restrictions worldwide, several alternate flame retardants are expected to see increased use as replacement compounds in consumer products. Chemical analysis of biosolids collected from wastewater treatment plants (WWTPs) can help determine whether these flame retardants are migrating from the indoor environment to the outdoor environment, where little is known about their ultimate fate and effects. The objective of this study was to measure concentrations of a suite of flame retardants, and the antimicrobial compound triclosan, in opportunistic samples of municipal biosolids and the domestic sludge Standard Reference Material (SRM) 2781. Grab samples of biosolids were collected from two WWTPs in North Carolina and two in California. Biosolids samples were also obtained during three subsequent collection events at one of the North Carolina WWTPs to evaluate fluctuations in contaminant levels within a given facility over a period of three years. The biosolids and SRM 2781 were analyzed for PBDEs, hexabromobenzene (HBB), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB), di(2-ethylhexyl)-2,3,4,5-tetrabromophthalate (TBPH), the chlorinated flame retardant Dechlorane Plus (syn- and anti-isomers), and the antimicrobial agent 5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan). PBDEs were detected in every sample analyzed, and ΣPBDE concentrations ranged from 1750 to 6358 ng/g dry weight. Additionally, the PBDE replacement chemicals TBB and TBPH were detected at concentrations ranging from 120 to 3749 ng/g dry weight and from 206 to 1631 ng/g dry weight, respectively. Triclosan concentrations ranged from 490 to 13,866 ng/g dry weight. The detection of these contaminants of emerging concern in biosolids suggests that these chemicals have the potential to migrate out of consumer products and enter the outdoor environment.