Alternate and new brominated flame retardants detected in U.S. house dust

Due to the voluntary withdrawals and/or bans on the use of two polybrominated diphenyl ether (PBDE) commercial mixtures, an increasing number of alternate flame retardant chemicals are being introduced in commercial applications. To determine if these alternate BFRs are present in indoor environments, we analyzed dust samples collected from 19 homes in the greater Boston, MA area during 2006. Using pure and commercial standards we quantified the following brominated flame retardant chemicals using GC/ECNI-MS methods: hexabromocyclododecane (sigma HBCD), bis(2,4,6,-tribromphenoxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), and the brominated components found in Firemaster 550 (FM 550): 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB) and (2-ethylhexyl)tetrabromophthalate (TBPH), the latter compound being a brominated analogue of di(2-ethylhexyl)phthalate (DEHP). The concentrations of all compounds were log-normally distributed and the largest range in concentrations was observed for HBCD (sum of all isomers), with concentrations ranging from <4.5 ng/g to a maximum of 130,200 ng/g with a median value of 230 ng/g. BTBPE ranged from 1.6 to 789 ng/g with a median value of 30 ng/g and DBDPE ranged from <10.0 to 11,070 ng/g with a median value of 201 ng/g. Of the FM 550 components, TBB ranged from <6.6 to 15,030 ng/g with a median value of 133 ng/g; whereas TBPH ranged from 1.5 to 10,630 ng/g with a median value of 142 ng/g. Furthermore, the ratio of TBB/TBPH present in the dust samples ranged from 0.05 to 50 (average 4.4), varying considerably from the ratio observed in the FM 550 commercial mixture (4:1 by mass), suggesting different sources with different chemical compositions, and/or differential fate and transport within the home. Analysis of paired dust samples collected from different rooms in the same home suggests HBCD, TBB, and TBPH are higher in dust from the main living area compared to dust collected in bedrooms; however, BTBPE and DBDPE levels were comparable between rooms. This study highlights the fact that numerous types of brominated flame retardants are present in indoor environments, raising questions about exposure to mixtures of these contaminants.     

In situ accumulation of HBCD, PBDEs, and several alternative flame-retardants in the bivalve (Corbicula fluminea) and gastropod (Elimia proxima)

Alternative brominated flame-retardants (BFRs), 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB), 2-ethylhexyl 2,3,4,5-tetrabromophthalate (TBPH), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE) and decabromodiphenyl ethane (DBDPE), are now being detected in the environment. However, contaminant bioavailability is influenced by the organisms' ecology (i.e., route of uptake) and in situ environmental factors. We observed that the filter-feeding bivalve (Corbicula fluminea) and grazing gastropod (Elimia proxima), collected downstream from a textile manufacturing outfall, exhibited TBB, TBPH, and BTBPE concentrations from 152 to 2230 ng g(-1) lipid weight (lw). These species also contained additional BFRs. Maximum levels of total hexabromocyclododecane diastereomers (∑HBCDs) in these species were 363,000 and 151,000 ng g(-1) lw, and those of polybrominated diphenyl ethers (∑PBDEs) were 64,900 and 47,200 ng g(-1) lw, respectively. These concentrations are among the highest reported to date worldwide. While BDE-209 was once thought to be nonbioavailable and resistant to degradation, it was the dominant BFR present and likely debromination products were detected. Contributions of α- and β-HBCD were higher in tissues than sediments, consistent with γ-HBCD bioisomerization. Mollusk bioaccumulation factors were similar between HBCD and PBDEs with 4 to 6 bromines, but factors for TBB, TBPH, and BTBPE were lower. Despite different feeding strategies, the bivalves and gastropods exhibited similar BFR water and sediment accumulation factors.     

Polybrominated diphenyl ethers vs alternate brominated flame retardants and Dechloranes from East Asia to the Arctic

Marine boundary layer air and seawater samples taken during a polar expedition cruise from East China Sea to the Arctic were analyzed in order to compare the occurrence, distribution, and fate of the banned polybrominated diphenyl ethers (PBDEs) with their brominated alternatives as well as the chlorinated Dechloranes. The sum of PBDEs (∑(10)PBDEs) in the atmosphere ranged from 0.07 to 8.1 pg m(-3) with BDE-209 being the dominating congener and from not detected (n.d.) to 0.6 pg L(-1) in seawater. Alternate brominated flame retardants (BFRs), especially hexabromobenzene (HBB), (2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE), pentabromotoluene (PBT), 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (EHTBB), bis-(2-ethylhexyl)-tetrabromophthalate (TBPH), were detected in higher concentrations than PBDEs, even in the high Arctic (0.6 to 15.4 pg m(-3) for sum of alternate BFRs), indicating the change of PBDEs toward alternate BFRs in the environmental predominance. In addition, Dechlorane Plus (DP) as well as Dechlorane 602, 603, and 604 were detected both in the atmosphere and in seawater. The highest concentrations as well as the highest compound variability were observed in East Asian samples suggesting the Asian continent as source of these compounds in the marine environment. The air-seawater exchange indicates strong deposition, especially of alternate BFRs, as well as dry particle-bound deposition of BDE-209 into the ocean.     

Brominated flame retardants and dechlorane plus in the marine atmosphere from Southeast Asia toward Antarctica

The occurrence, distribution, and temperature dependence in the marine atmosphere of several alternative brominated flame retardants (BFRs), Dechlorane Plus (DP) and polybrominated diphenyl ethers (PBDEs) were investigated during a sampling cruise from the East Indian Archipelago toward the Indian Ocean and further to the Southern Ocean. Elevated concentrations were observed over the East Indian Archipelago, especially of the non-PBDE BFR hexabromobenzene (HBB) with concentrations up to 26 pg m(-3) which were found to be related to continental air masses from the East Indian Archipelago. Other alternative BFRs- pentabromotoulene (PBT), pentabromobenzene (PBBz), and 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE)-were elevated, too, with concentrations up to 2.8, 4.3, and 2.3 pg m(-3), respectively. DP was detected from 0.26 to 11 pg m(-3) and bis-(2-ethylhexyl)-tetrabromophthalate (TBPH) ranged from not detected (nd) to 2.8 pg m(-3), respectively. PBDEs ranged from nd to 6.6 pg m(-3) (Σ(10)PBDEs) with the highest individual concentrations for BDE-209. The approach of Clausius-Clapeyron (CC) plots indicates that HBB is dominated by long-range atmospheric transport at lower temperatures over the Indian and Southern Ocean, while volatilization processes and additional atmospheric emissions dominate at higher temperatures. In contrast, BDE-28 and -47 are dominated by long-range transport without fresh emissions over the entire cruise transect and temperature range, indicating limited fresh emissions of the meanwhile classic PBDEs.     

Concentrations and spatial variations of polybrominated diphenyl ethers and other organohalogen compounds in Great Lakes air

Air samples were analyzed from urban, rural, and remote sites near the Great Lakes to investigate the occurrence, concentrations, and spatial and temporal differences of polybrominated diphenyl ethers (PBDE) in air. The concentrations of PBDEs were compared to those of other organohalogen compounds such as PCBs and organochlorine pesticides. The samples were collected in 1997-1999 as part of the Integrated Atmospheric Deposition Network (IADN). To minimize the variability of the data, we selected only samples taken when the atmospheric temperature was 20 +/- 3 degrees C. PBDEs were found in all samples, indicating that these compounds are widely distributed and that they can be transported through the atmosphere to remote areas. The total concentrations of PBDEs were similar to some of the organochlorine pesticides such as sigmaDDT and ranged from 5 pg/m3 near Lake Superior to about 52 pg/m3 in Chicago. In fact, the spatial trend was well correlated to those of PCBs. Our results indicate a relatively constant level from mid-1997 to mid-1999. At 20 +/- 3 degrees C, about 80% of the tetrabromo homologues are in the gas phase and about 70% of the hexabromo homologues are associated with the particle phase. Thus, particle-to-gas partitioning in the atmosphere is an important process for these compounds.     

Air-surface exchange of polybrominated diphenyl ethers and polychlorinated biphenyls

Air and leaf-litter samples were collected from a rural site in southern Ontario under meteorologically stable conditions in the early spring, prior to bud burst, over a three-day period to measure the simultaneous diurnal variations in polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). PBDEs are used in a wide range of commercial products as flame retardants and are being assessed internationally as potential persistent organic pollutants. Total PBDE concentrations in the air ranged between 88 and 1250 pg m(-3), and were dominated primarily by the lighter congeners PBDEs 17, 28, and 47, and concentrations of total PCBs ranged between 96 and 950 pg m(-3), and were dominated by the lower chlorinated (tri- to tetra-) congeners. Slopes of Clausius-Clapeyron plots indicate that both PCBs and PBDEs are experiencing active air-surface exchange. Fugacities were estimated from concentrations in the air and leaf-litter and suggest near equilibrium conditions. Following the three-day intensive sampling period, 40 air samples were collected at 24-hour intervals in an attempt to evaluate the effect of bud burst on atmospheric concentrations. Total PBDE concentrations in the daily air samples ranged between 10 and 230 pg m(-3), and were dominated by the lighter congeners PBDE 17, 28, and 47, whereas concentrations of total PCBs ranged between 30 and 450 pg m(-3) during this period. It is hypothesized thatthe high PBDE concentrations observed at the beginning of the sampling period are the result of an "early spring pulse" in which PBDEs deposited in the snowpack over the winter are released with snowmelt, resulting in elevated concentrations in the surface and air. Later in the sampling period, following bud burst, PBDE concentrations in air fell to 10 to 20 pg m(-3), possibly due to the high sorption capacity of this freshly emerging foliage compartment.     

PBDEs in the atmosphere of three locations in western Europe

Atmospheric concentrations of PBDEs (108 samples in total) were measured at 2 rural/semirural sites in England and 1 remote site on the west coast of Ireland in the years 2001 and 2000, respectively. Detailed analysis of the factors affecting concentrations is performed. The United Kingdom (UK) has been a major producer and user of PBDEs. Concentrations of sigmaPBDEs at Mace Head (MH), Ireland ranged between 0.22 and 5.0 pg m(-3) with a mean of 2.6 pg m(-3) and were controlled primarily by advection. sigmaPBDEs concentrations at Hazelrigg (HR), northwest England, ranged between 2.8 and 37 pg m(-3) with a mean of 12 pg m(-3) and at Chilton (CH), southwest England between 3.4 and 33 pg m(-3) with a mean of 11 pg m(-3). The average mixture of PBDEs in air was similar to that of commercial penta-BDE products. Movement of air over local/regional sources influenced concentrations of PBDEs at all sites, particularly at MH. At the two English sites during the summer, concentrations of PBDEs were strongly influenced bytemperature, indicating that air-surface exchange processes play an important role. Advection became more influential during winter, particularly at CH, where a different congener profile was observed in some samples as ambient air temperatures decreased and PBDE concentrations increased. It is hypothesized that this was due to increased emissions from diffuse combustion sources.     

Spatial distribution of polybrominated diphenyl ethers in southern Ontario as measured in indoor and outdoor window organic films

Organic films were collected from indoor and outdoor window surfaces, along an urban-rural transect extending northward from Toronto, Ontario, Canada, and analyzed for 41 polybrominated diphenyl ether congeners (PBDE). For exterior films, urban sigmaPBDE concentrations were approximately 10x greater than rural concentrations, indicating an urban-rural gradient and greater PBDE sources in urban areas. Urban films ranged from 2.5 to 14.5 ng/m2 (mean = 9.0 ng/ m2), excluding the regional "hotspot" Electronics Recycling Facility, compared to 1.1 and 0.56 ng/m2 at the Suburban and Rural sites. Interior urban films (mean = 34.4 ng/m2) were 3 times greater than rural films (10.3 ng/m2) and were representative of variations in building characteristics. Indoor films were 1.5-20 times greater than outdoor films, consistent with indoor sources of PBDEs and enhanced degradation in outdoor films. Congener profiles were dominated by BDE-209 (51.1%), consistent with deca-BDE as the main source mixture, followed by congeners from the penta-BDE mixture (BDE-99:13.6% and -47:9.4%) and some octa-BDE (BDE-183:1.5%). Congener patterns suggest a degradative loss of lower brominated compounds in outdoor films versus indoor films. Gas-phase air concentrations were back-calculated from film concentrations using the film-air partition coefficient (K(FA)). Mean calculated air concentrations were 4.8 pg/m3 for outdoor and 42.1 pg/m3 for indoor urban sites, indicating that urban indoor air is a source of PBDEs to urban outdoor air and the outdoor regional environment.     

Hexachlorocyclohexanes and endosulfans in urban, rural, and high altitude air samples in the Fraser Valley, British Columbia: evidence for trans-Pacific transport

High-volume air samples collected over the period Aug. 14-30, 2001, in the Lower Fraser Valley, BC, Canada, were used to assess urban/rural differences of organochlorine pesticides (OCPs) for ground level samples and to attempt to directly measure events of trans-Pacific inputs through the mid-troposphere. Hexachlorocyclohexanes (alpha- and gamma-isomers; 2-25 pg m(-3)) and endosulfan1 and -2 (5-150 pg m(-3)) were detected in all ground level samples. Seven air samples were collected during mid-troposphere flights (approximately 4400 m altitude) over the Lower Fraser Valley. These flights occurred concurrently with ground level sampling. Trajectory analysis identified three events of substantial mid-troposphere, trans-Pacific flow where 10-day back trajectories stemmed from potential source regions in Asia. These events were also characterized by higher air concentrations of alpha-HCH at 4400 m as compared to the ground level stations. This represents the first event-based, aircraft measurement of advection inputs of OCPs in the mid-troposphere of the west coast of North America.     

Passive and active air samplers as complementary methods for investigating persistent organic pollutants in the Great Lakes Basin

Data obtained using passive air samplers (PAS) are compared to active high-volume air sampling data in order to assess the feasibility of the PAS as a method, complementary to active high-volume air sampling (AAS), for monitoring levels of organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) in the Laurentian Great Lakes. PAS were deployed at 15 of the Integrated Atmospheric Deposition Network (IADN) sites on a quarterly basis between July 2002 and June 2003, and PAS and AAS results are compared. Levels for the OC pesticides are typically highest in agricultural areas, with endosulfan I dominating air concentrations with values ranging between 40 and 1090 pg x m(-3), dieldrin values between 15 and 165 pg x m(-3), and gamma-HCH values between 13 and 100 pg x m(-3). alpha-HCH was seen to be relatively uniform across the Great Lakes Basin with values ranging between 15 and 73 pg x m(-3). Large urban centers, such as Chicago and Toronto, have the highest levels of PCBs and PBDEs that range between 400 and 1200 pg x m(-3) and 10 and 70 pg x m(-3), respectively. Comparison of the AAS and the PAS data collected during this study shows good agreement, within a factor of 2 or 3, suggesting that the two sample methods produce comparable results. It is suggested that PAS networks, while providing data that are different in nature from AAS, can provide a cost-effective and complementary approach for monitoring the spatial and temporal trends of persistent organic pollutants.     

Air-sea exchange fluxes of synthetic polycyclic musks in the North Sea and the Arctic

Synthetic polycyclic musk fragrances Galaxolide (HHCB) and Tonalide (AHTN) were measured simultaneously in air and seawater in the Arctic and the North Sea and in the rural air of northern Germany. Median concentrations of gas-phase HHCB and AHTN were 4 and 18 pg m(-3) in the Arctic, 28 and 18 pg m(-3) in the North Sea, and 71 and 21 pg m(-3) in northern Germany, respectively. Various ratios of HHCB/AHTN implied that HHCB is quickly removed by atmospheric degradation, while AHTN is relatively persistent in the atmosphere. Dissolved concentrations ranged from 12 to 2030 pg L(-1) for HHCB and from below the method detection limit (3 pg L(-1)) to 965 pg L(-1) for AHTN with median values of 59 and 23 pg L(-1), respectively. The medians of volatilization fluxes for HHCB and AHTN were 27.2 and 14.2 ng m(-2) day(-1) and the depositional fluxes were 5.9 and 3.3 ng m(-2) day(-1), respectively, indicating water-to-air volatilization is a significant process to eliminate HHCB and AHTN from the North Sea. In the Arctic, deposition fluxes dominated the air-sea gas exchange of HHCB and AHTN, suggesting atmospheric input controls the levels of HHCB and AHTN in the polar region.     

Perfluorinated chemicals in the arctic atmosphere

Twenty high-volume air samples were collected during a crossing of the North Atlantic and Canadian Archipelago in July 2005 to investigate air concentrations of fluorotelomer alcohols (FTOHs) and perfluoalkyl sulfonamido ethanols (PFASs). These commercial chemicals are widely used as surface treatments and are believed to be precursors for perfluorocarboxylic acids (PFCAs) and perfluorooctane sulfonate (PFOS) that accumulate in humans and biota, including those from remote arctic regions. The highest concentrations (sum of gas- and particle-phase) of FTOHs were for 8:2 FTOH (perfluoroctyl ethanol) (5.8-26 pg/m(3)), followed by 10:2 FTOH (perfluorodecyl ethanol) (1.9-17 pg/ m(3)) and 6:2 FTOH (perfluorohexyl ethanol) [BDL (below detection limit) to 6.0 pg/m(3)]. For the PFASs, MeFOSE (N-methyl perfluorooctane sulfonamido ethanol) was dominant and ranged from 2.6 to 31 pg/m(3); EtFOSE (N-ethyl perfluorooctane sulfonamido ethanol) ranged from BDL to 8.9 pg/m(3) and MeFOSEA (N-methyl perfluorooctane sulfonamide ethylacrylate) was BDL in all samples. Air parcel back-trajectories showed that the sampled air was largely representative of the arctic air mass. Air concentrations of target compounds were of the same order of magnitude as reported air concentrations in source regions. For instance, the mean 8:2 FTOH concentration was only a factor of about 3 lower than for three urban samples that were collected in Toronto for comparison. These findings confirm model results that predictthe efficient, long-range atmospheric transport and widespread distribution of FTOHs and related compounds in the arctic region. Mean particulate percentages for FTOHs and PFASs in the cruise samples (mean temperature, 5+/-4 degrees C) were BDL for 6:2 FTOH, 23% for 8:2 FTOH, 15% for 10:2 FTOH, 32% for MeFOSE, and 22% for EtFOSE. Further, the partitioning to particles for MeFOSE and EtFOSE was significantly correlated with inverse absolute temperature, whereas the FTOHs did not show this trend. The Toronto samples (mean temperature, -1+/-1 degree C) showed similar particulate percentages for MeFOSE and EtFOSE; however, the FTOHs were substantially less particle-bound. Although the mechanism for this partitioning is not understood, the results do indicate the need to better account for particle phase transport when modeling the atmospheric fate of these chemicals.     

Atmospheric semivolatile organochlorine compounds in European high-mountain areas (central Pyrenees and high Tatras)

Atmospheric samples from two European high-mountain areas showed similar composition of semivolatile organochlorine compounds (SOC), such as polychlorobiphenyls (PCBs), DDTs, endosulfans, hexachlorobenzene (HCB), and hexachlorocyclohexanes (HCHs). Nearly all compounds were predominantly found in the gas phase and only the less volatile such as some PCBs (e.g., 149, 118, 153, 138, and 180) were found in higher abundance in the particulate phase. HCB, 49-85 pg m(-3), is the dominant SOC. This compound is only found in the gas phase exhibiting uniform concentrations irrespective of season and air mass origin. SOC of present use, like HCHs and endosulfans, were found in higher concentrations in the warm periods, 32-46 and 4-10 pg m(-3) in the gas + particulate phases, respectively, reflecting their seasonal pattern of use in many European countries. PCB and 4,4'-DDE, 39-42 and 4-6 pg m(-3) in the gas + particulate phases, respectively, also showed a seasonal trend despite neither the former nor the precursor of the latter (4,4'-DDT) being manufactured with their use drastically restricted since the 1980s. The seasonal differences are mainly due to a higher occurrence of air masses with strong continental inputs in the warm than in the cold periods. In this respect, samples whose air masses traveled at the high troposphere (backward air mass trajectories >6000 m) have been observed to carry considerably smaller PCB and 4,4'-DDE loads (9.3 +/- 2.8 and 0.4 +/- 0.05 pg m(-3), respectively) than overall average.     

Platinum and rhodium concentrations in airborne particulate matter in Germany from 1988 to 1998

Increases in platinum group element (PGE) concentrations in ambient air and dust since the introduction of automotive catalytic converters in 1988 is a cause of concern. Until now, data derived from engine-test bench experiments have provided the basis for the assessment of human health risks associated with PGE exposure. Such experiments have provided valuable information regarding emission data that has been used to estimate ambient exposure concentrations. However, these data are not necessarily representative of typical environmental PGE exposure levels and conditions. Data on measured environmental concentrations is needed to provide a more adequate basis for the assessment of exposure and related risks. Twenty air and airborne-dust samples were provided by the Umweltbundesamt (Federal Environmental Agency, Germany) in the years 1988, 1989, 1992, 1997, and 1998. The samples were collected in Frankfurt/Main and the adjacent city of Offenbach. For this, 11 to 80 m3 of air were filtered over a 24-72 h period using a vacuum. Glass-fiber filters were used to collect samples. Sample platinum and rhodium concentrations were determined using adsorptive voltammetry. Although the number of samples collected in different years is limited, the results indicate a trend toward continuous increases in ambient concentrations of these metals between 1988 and 1998. Specifically, there were 46- and 27-fold increases in Pt and Rh concentrations, respectively. Despite these observed increases, the Pt concentrations measured (i.e., 147 pg/m3 on average, with a maximum of 246 pg/m3 in 1998) fell far below 15,000 pg/m3, which has been suggested as a guidance value (i.e., exposure at this level would be expected to be without appreciable health risk). The results of a particle-size distribution analysis of one sample (8-step impactor) that was collected 150 m away from a street show that approximately 75% of Pt and 95% of Rh occurs in association with large particulate matter of > 2 microns, with concentrations reaching a maximum in particles of 4.7 to 5.8 microns. The remaining 25% of Pt and 5% of Rh is present in fine particulate matter of < 2 microns. An approximate 10% of Pt and < 38% of Rh in airborne particles was found to be soluble in 0.1 molar HCl. Further, the results indicate that most of the emitted PGE particles from automotive catalytic converters, particularly those bound to fine particulate matter, are capable of being airborne. As a result, PGEs are not only present in areas close to emissions (e.g., roads), but can be transported over longer distances.     

Concentrations and profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans in soils from Korea

Soil samples were collected from Changwon and Masan Cities, Korea, and analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/DFs). Nearly all tetra- through octachlorinated PCDDs/DFs including the 17 2,3,7,8-substituted PCDDs/DFs were detected in all samples. Total concentrations of PCDDs/DFs and of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TeCDD) equivalents (TEGs) in soils ranged from 35 to 121,400 pg/g, dry weight, and from 0.2 to 3720 pg of I-TEQ/g, respectively. On the basis of guidelines for TEQ concentrations established in Germany and the United States, 9 of 23 soil samples (39% of the total samples analyzed) could not be expected to pose human health hazards. The rest of 61% of soils need measures such as investigations of source identification, soil decontamination, and/or soil removal. Total concentrations of PCDDs/DFs were greater at or near four industrial sites, which are concerned with the steel industry, petrochemical-related industry, and industrial waste incineration, than other areas. This indicates the presence of potential source areas. Soil collected from a site 50 m from an open-burning industrial waste incinerator in an industrial complex was heavily contaminated, containing a total concentration of PCDDs/DFs of 121,400 pg/g, dry weight. PCDDs/DFs were also detected in soils from the top of a 200 m mountain indicating a wide dispersal of PCDDs/DFs by atmospheric transport from point source areas. The congener pattern and relative proportions of PCDFs in soils suggest that commercial PCB preparations such as Kanechlors may be one of the sources. The wide range of PCDD/DF isomers detected in soils from many locations also suggests a multitude of sources, in addition to commercial PCBs, such as incineration of industrial wastes such as car tires, scrap wires, plastics, papers, and emission of automobile exhaust.     

Detailed study of factors controlling atmospheric concentrations of PCNs

Atmospheric concentrations of polychlorinated naphthalenes (PCNs) (108 samples in total) were measured at two rural/ semirural sites in England and one remote site on the west coast of Ireland in the years 2001 and 2000, respectively. Detailed analysis of the factors affecting concentrations is performed. At Mace Head (MH) Ireland, concentrations of sigmaPCNs ranged between 1.7 and 55 pg m(-3) with a mean of 15 pg m(-3) and were controlled primarily by advection. sigmaPCNs concentrations at Hazelrigg (HR), northwest England, ranged between 31 and 310 pg m(-3) with a mean of 110 pg m(-3), and at Chilton (CH), southwest England, ranged between 31 and 180 pg m(-3) with a mean of 85 pg m(-3). Data from the HR site shows that PCN concentrations have not declined between the early 1990s and 2001, while PCB concentrations have declined. The ratio of the sigmaPCNs/ sigmaPCBs was close to or greater than 1 at all sites. From air mass back trajectories, it is clear that local/regional sources influenced concentrations of PCNs at all sites, particularly at MH. At the two English sites during the summer, concentrations of PCNs were strongly influenced by temperature, indicating that air-surface exchange processes play an important role. Advection became more influential during winter, particularly at CH, where a different homologue profile was observed in some samples when air masses approached from the southwest and PCN concentrations increased. The average mixture profile of PCNs in air was similar to that observed in other studies and different from that in Halowax 1014.     

Indoor air is a significant source of tri-decabrominated diphenyl ethers to outdoor air via ventilation systems

Ventilation of indoor air has been hypothesized to be a source of PBDEs to outdoors. To study this, tri-decabrominated diphenyl ethers were analyzed in outgoing air samples collected inside ventilation systems just before exiting 33 buildings and compared to indoor air samples from microenvironments in each building collected simultaneously. Median ∑(10)PBDE (BDE- 28, -47, -99, -153, -183, -197, -206, -207, -208, -209) concentrations in air from apartment, office and day care center buildings were 93, 3700, and 660 pg/m(3) for outgoing air, and 92, 4700, and 1200 pg/m(3) for indoor air, respectively. BDE-209 was the major congener found. No statistically significant differences were seen for individual PBDE concentrations in matched indoor and outgoing air samples, indicating that outgoing air PBDE concentrations are equivalent to indoor air concentrations. PBDE concentrations in indoor and outgoing air were higher than published outdoor air values suggesting ventilation as a conduit of PBDEs, including BDE-209, from indoors to outdoors. BDE-209 and sum of BDE-28, -47, -99, and -153 emissions from indoor air to outdoors were roughly estimated to represent close to 90% of total emissions to outdoor air for Sweden, indicating that contaminated indoor air is an important source of PBDE contamination to outdoor air.     

Spray irrigation of treated municipal wastewater as a potential source of atmospheric PBDEs

Spray irrigation facilities utilizing treated municipal wastewater are a potential source of polybrominated diphenyl ethers (PBDEs) to the atmosphere. PBDEs are used as flame retardants in many household items and have been found in wastewaters and biosolids. Evidence of PBDE release from spray irrigation facilities was discovered during a multiyear project to measure semivolatile organic chemical concentrations in air. Four BDE congeners (47, 99, 100, and 154) were monitored at three remote/ rural locations in Maryland and Delaware from 2001 to 2003. Average concentrations at two of the sites (BDE-47, 10-17 pg/m3; BDE-99, 5.3-7.7 pg/m3) reflect background levels. Average concentrations at the third location were 5-10 times higher (BDE-47, 175 pg/m3; BDE-99, 26 pg/m3) and were significantly correlated (p < 0.0001) with temperature indicating local source(s). Several spray irrigation facilities are located south and west of the third site, the prevailing wind direction during the spring and summer when most samples were collected. The fine mist released from the irrigation equipment may enhance release to the atmosphere via air-water gas exchange from water droplets. Temporal trends indicate that aerial concentrations of PBDEs in this area are increasing at an exponential rate; the atmospheric doubling times for the different congeners range from 1.1 to 1.7 yrs.     

Atmospheric HCH concentrations over the Marine Boundary Layer from Shanghai, China to the Arctic Ocean: role of human activity and climate change

From July to September 2008, air samples were collected aboard the research expedition icebreaker XueLong (Snow Dragon) as part of the 2008 Chinese Arctic Research Expedition Program. Hexachlorocyclohexane (HCH) concentrations were analyzed in all of the samples. The average concentrations (± standard deviation) over the entire period were 33 ± 16, 5.4 ± 3.0, and 13 ± 7.5 pg m?3 for α-, β- and γ-HCH, respectively. Compared to previous studies in the same areas, total HCH (ΣHCH, the sum of α-, β-, and γ-HCH) levels declined by more than 10 × compared to those observed in the 1990s, but were approximately 4 × higher than those measured by the 2003 China Arctic Research Expedition, suggesting the increase of atmospheric ΣHCH recently. Because of the continuing use of lindane, ratios of α/γ-HCH showed an obvious decrease in North Pacific and Arctic region compared with those for 2003 Chinese Arctic Research Expedition. In Arctic, the level of α-HCH was found to be linked to sea ice distribution. Geographically, the average concentration of α-HCH in air samples from the Chukchi and Beaufort Seas, neither of which contain sea ice, was 23 ± 4.4 pg m?3, while samples from the area covered by seasonal ice (～75°N to ～83°N), the so-called "floating sea ice region", contained the highest average levels of α-HCH at 48 ± 12 pg m?3, likely due to emission from sea ice and strong air-sea exchange. The lowest concentrations of α-HCH were observed in the pack ice region in the high Arctic covered by multiyear sea ice (～83°N to ～86°N). This phenomenon implies that the re-emission of HCH trapped in ice sheets and Arctic Ocean may accelerate during the summer as ice coverage in the Arctic Ocean decreases in response to global climate change.     

Wastewater treatment plant and landfills as sources of polyfluoroalkyl compounds to the atmosphere

Polyfluoroalkyl compounds (PFCs) were determined in air around a wastewater treatment plant (WWTP) and two landfill sites using sorbent-impregnated polyurethane foam (SIP) disk passive air samplers in summer 2009. The samples were analyzed for five PFC classes (i.e., fluorotelomer alcohols (FTOHs), perfluorooctane sulfonamides (FOSAs), sulfonamidoethanols (FOSEs), perfluoroalkyl sulfonic acids (PFSAs), and perfluoroalkyl carboxylic acids (PFCAs)) to investigate their concentration in air, composition and emissions to the atmosphere. ∑PFC concentrations in air were 3-15 times higher within the WWTP (2280-24?040 pg/m(3)) and 5-30 times higher at the landfill sites (2780-26?430 pg/m(3)) compared to the reference sites (597-1600 pg/m3). Variations in the PFC pattern were observed between the WWTP and landfill sites and even within the WWTP site. For example, FTOHs were the predominant PFC class in air for all WWTP and landfill sites, with 6:2 FTOH as the dominant compound at the WWTP (895-12?290 pg/m(3)) and 8:2 FTOH dominating at the landfill sites (1290-17?380 pg/m(3)). Furthermore, perfluorooctane sulfonic acid (PFOS) was dominant within the WWTP (43-171 pg/m(3)), followed by perfluorobutanoic acid (PFBA) (55-116 pg/m(3)), while PFBA was dominant at the landfill sites (101-102 pg/m(3)). It is also noteworthy that the PFCA concentrations decreased with increasing chain length and that the emissions for the even chain length PFCAs outweighed emissions for the odd chain length compounds. Furthermore, highly elevated PFC concentrations were found near the aeration tanks compared to the other tanks (i.e., primary and secondary clarifier) and likely associated with increased volatilization during aeration that may be further enhanced through aqueous aerosol-mediated transport. ∑PFC yearly emissions estimated using a simplified dispersion model were 2560 g/year for the WWTP, 99 g/year for landfill site 1, and 1000 g/year for landfill site 2. These results highlight the important role of WWTPs and landfills as emission sources of PFCs to the atmosphere.