Organophosphorus flame retardants (PFRs) and phthalates in floor and road dust from a manual e-waste dismantling facility and adjacent communities in Thailand.

This study was undertaken to investigate levels of organophosphorus flame retardants (PFRs) and phthalates in floor and road dust from a manual e-waste dismantling facility and nearby communities in Thailand. Concentrations of Σ10 PFRs and Σ6 phthalates in floor dust from the facility were approximately 36-1,700 and 86,000-790,000 ng g-1, whereas those from the communities were about 13-9,200 and 44,000-2,700,000 ng g-1, respectively. The highest content of Σ10 PFRs (9,200 ng g-1) and Σ6 phthalates (2,700,000 ng g-1) in indoor dust was both detected in the dust sampled from a house with no prevailing winds located 350 m northeast of the facility. Levels of Σ10 PFRs and Σ6 phthalates in road dust from the facility were around 1,100-2,100 and 40,000-670,000 ng g-1, while those from the residences were about 650-2,000 and 27,000-650,000 ng g-1, respectively. Concentrations of Σ10 PFRs (2,100 ng g-1) and Σ6 phthalates (670,000 ng g-1) in road dust were greatest in the dust collected from the facility. For the distributional pattern, TBEP (tris (2-butoxyethyl) phosphate) was the main PFR in residential dust, whereas TPP (triphenyl phosphate) was the major PFR in facility dust. TBEP was also found to be the most prominent PFR in all road dust samples. Furthermore, DEHP (di-2-ethylhexyl phthalate) was the most abundant phthalate congener in both floor and road dust samples. Under realistic high-end scenarios of environmental exposure to DEHP, Thai toddlers (25.29 µg kg-1 bw day-1) in the adjacent communities were exposed above the US EPA's (United States Environmental Protection Agency) reference dose (RfD) for this congener (20 µg kg-1 bw day-1). Our data reveal that the PFR and phthalate-containing products at the residences are a likely substantial source of PFRs and phthalates to the surrounding indoor environment, and humans can be exposed to PFRs and phthalates in their dwellings via the settled floor dust.

Polybrominated diphenyl ethers (PBDEs) in floor and road dust from a manual e-waste dismantling facility and adjacent communities in Thailand.

This study characterizes concentrations of polybrominated diphenyl ethers (PBDEs) in floor and road dust from a manual e-waste dismantling facility and adjacent communities in Thailand. Levels of Σ22 PBDEs in floor dust from the facility varied between 1,200 and 43,000 ng g-1, whereas those from adjacent communities were in the range 6.6-2,200 ng g-1. Concentrations of Σ22 PBDEs (43,000 ng g-1) were highest in floor dust collected from the facility. Levels of Σ22 PBDEs and all congeners studied, except for BDE-66, BDE-71, BDE-85, BDE-119, BDE-138, BDE-190 and BDE-191 in facility dust were significantly greater than those in residential dust (P = <0.001-0.017). Moreover, PBDE contents decreased with increasing distance from the facility, revealing that the facility may represent a principal source of PBDEs to the surrounding environment. Levels of Σ22 PBDEs in road dust from the facility varied from 27 to 21,000 ng g-1, while those from the adjacent residences were about 5.4-63 ng g-1. Concentrations of Σ22 PBDEs (21,000 ng g-1) were highest in road dust taken at the facility. The PBDE congener profile for floor dust from the facility was dominated by BDEs 28, 47 and 209, whereas domestic floor dust was predominated by BDEs 206 and 209. Under various scenarios of occupational and environmental exposure to BDE-99 and BDE-209, workers in the facility as well as adults and children in the adjacent communities were exposed below the United States Environmental Protection Agency (US EPA)'s reference doses (RfDs) for BDE-99 (100 ng/kg bw/day) and BDE-209 (7,000 ng/kg bw/day).

Product screening for sources of halogenated flame retardants in Canadian house and office dust.

Human exposure to halogenated flame retardants (HFRs) such as polybrominated diphenyl ethers (PBDEs) and their replacements, can be related to exposure to indoor dust and direct contact with HFR-containing products. This study aimed to identify electronic products that contributed to HFRs measured in indoor dust and to develop a screening method for identifying HFRs in hard polymer products. Concentrations of 10 PBDEs and 12 halogenated replacements in dust and surface wipe samples of hard polymer casings of electronic products plus Br in the surfaces of those casing measured using X-ray fluorescence (XRF) were analyzed from 35 homes and 10 offices in Toronto (ON, Canada). HFR concentrations in dust and product wipes were positively correlated. Thus, we hypothesize that electronic products with the highest HFR concentrations contribute the most to concentrations in dust, regardless of the volatility of the HFR. Abundant HFRs in dust and product wipes were PBDEs (BDE-47, 99, 100, 153, 154, 183, 209), TDCPP, DBDPE, EH-TBB and BEHTBP. Older CRT TVs had the highest concentration of BDE-209 of all products tested. This was followed by higher concentrations of HFRs in PCs, Audio/Video (A/V) devices, small household appliances (HHAs) and flat screen TVs. The removal of HFRs from polymer surfaces using wipes supports concerns that HFRs could be transferred from these surfaces to hands as a result of direct contact with HFR-containing products. Surface wipe testing shows promise for screening additive HFRs. In comparison, the Br-content obtained using a handheld XRF analyzer did not correspond to concentrations obtained from surface wipe testing.

Interlaboratory study of novel halogenated flame retardants: INTERFLAB.

Flame retardants (FRs) have come under considerable scientific and public scrutiny over the past decade. A lack of reference materials and standardized analytical methods has resulted in questions regarding the variation of measurements from different studies. We evaluated this variation by performing an international interlaboratory study assessing analytical capabilities as well as the accuracy and precision of results for a range of flame retardants (International Flame Retardant Laboratory Study, INTERFLAB). Thirteen international research laboratories participated in a blind interlaboratory comparison of 24 FRs. Results demonstrate good precision within replicates of test mixtures from individual laboratories, but problematic accuracy for several FRs and laboratories. Large ranges in the values reported for decabromodiphenylethane (DBDPE), tris(1,3-dichloropropyl)phosphate (TDCIPP), tetrabromobisphenol-A (TBBPA), and hexabromocyclododecane (HBCD) (>50 % relative standard deviations among measured values) and large deviations from the reference values (>25 % bias in accuracy) suggest potential problems for comparability of results. DBDPE, HBCD, and TBBPA had significantly poorer accuracy and precision, suggesting that current analytical methods are not providing reliable results for these FRs.

Calibration of two passive air samplers for monitoring phthalates and brominated flame-retardants in indoor air.

Two passive air samplers (PAS), polyurethane foam (PUF) disks and Sorbent Impregnated PUF (SIP) disks, were characterized for uptake of phthalates and brominated flame-retardants (BFRs) indoors using fully and partially sheltered housings. Based on calibration against an active low-volume air sampler for gas- and particle-phase compounds, we recommend generic sampling rates of 3.5±0.9 and 1.0±0.4 m(3)/day for partially and fully sheltered housing, respectively, which applies to gas-phase phthalates and BFRs as well as particle-phase DEHP (the later for the partially sheltered PAS). For phthalates, partially sheltered SIPs are recommended. Further, we recommend the use of partially sheltered PAS indoors and a deployment period of one month. The sampling rate for the partially sheltered PUF and SIP of 3.5±0.9 m(3)/day is indistinguishable from that reported for fully sheltered PAS deployed outdoors, indicating the role of the housing outdoors to minimize the effect of variable wind velocities on chemical uptake, versus the partially sheltered PAS deployed indoors to maximize chemical uptake where air flow rates are low.

Concentrations of polybrominated diphenyl ethers in matched samples of indoor dust and breast milk in New Zealand.

Polybrominated diphenyl ethers (PBDEs) are present in many consumer goods. There is evidence that PBDEs are toxic to humans, particular young children. The purpose of this study was to assess indoor dust as an exposure source for PBDEs. Concentrations of 16 PBDEs were determined in dust samples from 33 households in New Zealand, and in breast milk samples from 33 mothers living in these households. Associations between dust and breast milk PBDE concentrations were assessed, and children's PBDE intake from breast milk and dust estimated. Influences of household and demographic factors on PBDE concentrations in dust were investigated. Indoor dust concentrations ranged from 0.1ng/g for BDE17 to 2500ng/g for BDE209. Breast milk concentrations were positively correlated (p<0.05) with mattress dust concentrations for BDE47, BDE153, BDE154, and BDE209 and with floor dust for BDE47, BDE183, BDE206, and BDE209. The correlation for BDE209 between dust and breast milk is a novel finding. PBDE concentrations in floor dust were lower from households with new carpets. The estimated children's daily intake of PBDEs from dust and breast milk was below U.S. EPA Reference Dose values. The study shows that dust is an important human exposure source for common PBDE formulations in New Zealand.

Perfluoroalkyl substances in UK indoor and outdoor air: spatial and seasonal variation, and implications for human exposure.

This study reports atmospheric concentrations of a number of perfluoroalkyl substances (PFASs) in homes, offices, and outdoor locations in Birmingham, UK during 2008 and 2009. Concentrations indoors exceed significantly those outdoors, suggesting indoor emissions are driving outdoor contamination. The exception is N-ethyl perfluorooctane sulfonamide (EtFOSA), for which indoor and outdoor concentrations are statistically indistinguishable, implying other sources for this compound. Concentrations of all PFASs at 10 urban outdoor locations showed little spatial variability (RSD=53-85%). At 2 urban locations and 1 semi-rural location in England, monthly variations in outdoor concentrations were measured over 1 year and shown to be in line (RSD=39-110%) with the low spatial variability in Birmingham. This low spatial and temporal variability implies sources at locations monitored are diffuse in nature. Concentrations of N-ethyl perfluorooctanesulfonamidoethanol (EtFOSE) in outdoor air were significantly higher at one of the Birmingham urban sites than at the semi-rural location. Indoor concentrations of perfluorohexanesulfonate (PFHxS) exceeded those of perfluorooctanesulfonate (PFOS). Combined with the fact that PFHxS concentrations in outdoor air in this study exceed substantially those measured in the UK in 2005; this is consistent with the hypothesis that PFHxS use is increasing in response to restrictions on the use of PFOS. Concentrations of PFOS in offices exceed significantly those in homes. Month-to-month variations in concentrations in 4 living rooms and 1 office were measured over a year. Relative standard deviations (RSD) for individual PFASs in these locations were 47-160%, providing information about the uncertainty associated with exposure assessments based on single measurements. The observed variability could not be attributed to changes in room contents, nor to seasonality. Human exposure via inhalation appears a minor pathway.

Occurrence of alternative flame retardants in indoor dust from New Zealand: indoor sources and human exposure assessment.

Due to worldwide restrictions on polybrominated diphenyl ethers (PBDEs), the demand for alternative flame retardants (AFRs), such as organophosphate flame retardants (OPFRs), novel brominated FRs (NBFRs) and hexabromocyclododecanes (HBCDs), has recently increased. Little is known about human exposure to NBFRs and OPFRs and that their levels in dust have been scarcely evaluated worldwide. To increase the knowledge regarding these chemicals, we measured concentrations of five major NBFRs, ten OPFRs and three HBCD isomers in indoor dust from New Zealand homes. Dust samples were taken from living room floors (n=34) and from mattresses of the same houses (n=16). Concentrations (ngg(-1)) of NBFRs were: 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) (<2-175), decabromodiphenyl ethane (DBDPE) (<5-1430), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB) (<2-2285) and bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBPH) (<2-640). For OPFRs, concentrations (ngg(-1)) ranged between: tri-ethyl-phosphate (TEP) (<10-235), tri-n-butyl-phosphate (TnBP) (<20-7545), tris-(2-chloroethyl)-phosphate (TCEP) (<20-7605), tris-(1-chloro-2-propyl) phosphate (TCPP) (20-7615), tri-(2-butoxyethyl)-phosphate (TBEP) (50-27325), tris-(2,3-dichloropropyl)-phosphate (TDCPP) (20-16560), tri-phenyl-phosphate (TPhP) (20-35190), and tri-cresyl-phosphate (TCP) (<50-3760). HBCD concentrations fell in the range <2-4100ngg(-1). BTBPE, DBDPE, TBPH, TBEP, and TnBP showed significant positive correlation (p<0.05) between their concentrations in mattresses and the corresponding floor dust (n=16). These data were used to derive a range of plausible exposure scenarios. Although the estimated exposure is well below the corresponding reference doses (RfDs), caution is needed given the likely future increase in use of these FRs and the currently unknown contribution to human exposure by other pathways such as inhalation and diet.

"Novel" brominated flame retardants in Belgian and UK indoor dust: implications for human exposure.

Concentrations of several "novel" brominated flame retardants (NBFRs) are reported in indoor dust samples from Belgian houses (n=39) and offices (n=6) and from day-care centers and schools in the West Midlands of the UK (n=36). Using a GC-ECNI/MS method, the following NBFRs were quantified: decabromodiphenyl ethane (DBDPE) (range <20-2470 ng g(-1)), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) (range <0.5-1740 ng g(-1)), tetrabromobisphenol A-bis(2,3-dibromopropylether) (TBBPA-DBPE) (range <20-9960 ng g(-1)), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB) (range <2-436 ng g(-1)) and bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBPH) (range <2-6175 ng g(-1)). Hexachlorocyclopentadienyl-dibromocyclooctane (HCDBCO), another NBFR, was below the detection limit of 2 ng g(-1) dust in all dust samples. No correlation was detected between concentrations of NBFRs and PBDEs. The ratio of TBB:TBPH in the dust samples ranged from 0.01 to 4.77 (average 0.42), compared to the ratio present in the commercial flame retardant product FM 550 (TBB:TBPH=4:1). Furthermore, no correlation was detected between concentrations in dust of TBB and TBPH. This may suggest different sources of these NBFRs, or similar sources but compound-specific differences in their indoor fate and transport. Exposure via dust ingestion was estimated for both adults and toddlers under low-end (5th percentile), typical (median), and high-end (95th percentile concentrations) scenarios. These were calculated assuming 100% absorption of intake dust and using mean dust ingestion (adults=20 mg d(-1); for toddlers=50 mg d(-1)) and high dust ingestion (adults=50 mg d(-1); for toddlers=200 mg d(-1)). Typical exposure with high dust ingestion estimates for adults were 0.01, 0.2, 0.01, 0.02 and 0.08 ng kg(-1) bw d(-1) and for toddlers 0.05, 1.9, 0.08, 0.4 and 1.12 ng kg(-1) bw d(-1) for BTBPE, DBDPE, TBB, TBPH and TBBPA-DBPE, respectively. Our results showed that, similar to PBDEs, toddlers have higher exposure to NBFRs than adults. This study documents the presence of NBFRs in indoor environments, and emphasizes the need to evaluate the health implications of exposure to such chemicals.

Perfluoroalkyl compounds in dust from Asian, Australian, European, and North American homes and UK cars, classrooms, and offices.

Perfluoroalkyl compounds (PFCs) were measured in dust from Australian, Canadian, French, German, Kazahkstani, Thai, UK, and US homes, and UK cars, classrooms, and offices. Most PFCs were significantly lower in Kazahkstan and Thailand than elsewhere; 2-(N-methylperfluoro-1-octanesulfonamido)-ethanol (MeFOSE) and 2-(N-ethylperfluoro-1-octanesulfonamido)-ethanol (EtFOSE) were significantly lower in Canada than in the UK and the US; perfluoro-1-hexanesulfonate (PFHxS) was significantly lower in Canada than in the UK, and N-ethylperfluoro-1-octanesulfonamide (EtFOSA) was significantly higher in Australia than in the UK. High EtFOSA concentrations in some samples may be consistent with its use as an insecticide. Perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), PFHxS, and MeFOSE were significantly higher in classrooms than in cars, homes, and offices; N-methylperfluoro-1-octanesulfonamide (MeFOSA) was significantly lower in classrooms than in homes and offices, and perfluoro-1-octanesulfonamide (FOSA) was significantly lower in classrooms than in cars, homes, and offices. While homes are usually the most important vector of dust exposure (typically > 60%), offices and classrooms make important contributions. While diet is usually the main exposure pathway for UK adults and children (~1-6 years) for PFOS, PFOA, and PFHxS; dust ingestion can be significant under high dust ingestion scenarios. Even under high-end exposure scenarios for dust and diet, PFOS and PFOA exposures are well within the European Food Safety Authority tolerable daily intakes.

Dust from U.K. primary school classrooms and daycare centers: the significance of dust as a pathway of exposure of young U.K. children to brominated flame retardants and polychlorinated biphenyls.

Polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), tetrabromobisphenol-A (TBBP-A), and polychlorinated biphenyls (PCBs) were measured in floor dust from U.K. child daycare center and primary school classrooms (n = 43, 36 for PCBs). Concentrations of HBCDs exceeded significantly (p < 0.05) those reported previously for U.K. houses and offices, while those of TBBP-A exceeded significantly those in U.K. cars and offices. PCB concentrations were statistically indistinguishable from those in U.K. house dust but lower than in U.S. classroom dust, while BDEs 47, 99, 100, 153, 196, 197, 203, and 209 in classrooms were significantly below concentrations in U.K. cars. Exposure of young U.K. children via classroom dust exceeds that of U.K. adults via office dust for all contaminants monitored. Overall dust exposure of young U.K. children was estimated including car, classroom, and house dust. Exposure to TBBP-A was well below a U.K. health-based limit value (HBLV). Though no HBLVs exist for non-dioxin-like PCBs and HBCDs; dust exposure to PCBs fell well below U.K. dietary and inhalation exposure. Contrastingly, a high-end estimate of HBCD dust exposure exceeded U.K. dietary exposure substantially. Moreover, high-end estimates of dust exposure to BDE-99 and BDE-209 (4.3 and 13000 ng/kg bw/day, respectively) exceeded HBLVs of 0.23-0.30 and 7000 ng/kg bw/day respectively.