Flame retardants in the atmosphere near the Great Lakes

As part of the Integrated Atmospheric Deposition Network (IADN), air samples were collected at five sites around the Great Lakes (two urban, two rural, and one remote) every 12 days during 2005-2006, and the concentrations of polybrominated diphenylethers (PBDEs), 1,2-bis(2,4,6-tribromophenoxy)-ethane (TBE), Dechlorane Plus (DP), and decabromodiphenyl ethane (DBD PE) were measured. The highest mean concentrations of total PBDEs were found at the urban sites in Chicago and Cleveland (65 +/- 4 and 87 +/- 8 pg/m3, respectively), and the lowest at the remote site in Eagle Harbor (5.8 +/- 0.4 pg/m3). With the exception of Chicago, the atmospheric concentrations of BDE-47 and 99 (summed over the gas and particle phases) are decreasing rapidly with half-lives of approximately 2 years, but the concentrations of BDE-209 are not decreasing at any of the five sites. The atmospheric partial pressures of BDE-47 and 99 showed a strong Clausius-Clapeyron relationship with reciprocal atmospheric temperature. TBE, DBDPE and DP were detected at all sites, but with the exception of Chicago, there were insufficient data to determine temporal trends for these compounds. The influence of human population density and synoptic atmospheric transport patterns was explored to explain the relatively high concentrations of BDE-209 in Cleveland.     

Novel flame retardants, 1,2-bis(2,4,6-tribromophenoxy)ethane and 2,3,4,5,6-pentabromoethylbenzene, in United States' environmental samples

Two brominated flame retardants, 1,2-bis(2,4,6-tribromophenoxy)ethane (TBE) and 2,3,4,5,6-pentabromoethylbenzene (PEB), were detected and identified in ambient air samples from various sites in the United States. The identifications were confirmed by comparing the gas chromatographic retention times and mass spectra of the compounds found in the environment with those of authentic materials. Generally, the TBE concentrations in air were comparable to those of tetra- through hexabrominated diphenyl ethers (PBDEs) and often higher than those of decabromodiphenyl ether (BDE-209). The atmospheric TBE concentrations at locations in the southern United States were higher than those in the northern United States. TBE was also found in a sediment core from Lake Michigan; the concentrations of TBE increased with time, were lower than those of BDE-209, but were approximately 10 times higher than the sum of BDE-47, -99, and -100. The maximum PEB concentration in Chicago air was 550 pg/ m3, which was 10 times higherthan the concentration of total PBDEs in this sample. In general, the concentrations of PEB in air samples were low but detectable and were less than those of PBDEs. PEB was not found in the sediment core from Lake Michigan. These occurrences of relatively high concentrations of TBE and PEB in environmental samples may reflect the increasing usage of these compounds as flame retardants.     

Preliminary assessment of U.K. human dietary and inhalation exposure to polybrominated diphenyl ethers

This study reports concentrations of BDEs 47, 99, 100, 153, and 154 in outdoor air [median sigmaPBDE (sum of BDEs 47, 99, 100, 153, and 154) = 18 pg m(-3)] in air from a range of office and home indoor microenvironments (median sigmaPBDE = 762 pg m(-3)) and vegan and omnivorous duplicate diet samples (median sigmaPBDE = 154 and 181 pg g(-1) dryweightforvegan and omnivorous diets, respectively). Median daily human exposure to sigmaPBDE via inhalation is 6.9 ng/person and 90.5 ng/person via diet but the relative significance of these pathways may vary considerably between individuals. Median concentrations in indoor air were higher in workplace (sigmaPBDE = 1082 pg m(-3)) than in domestic (sigmaPBDE = 128 pg m(-3)) microenvironments, and substantial differences in concentrations in air from different rooms in the same office building were found. When data from the only mechanically ventilated room was excluded, a significant positive correlation (p < 0.001) was observed between PBDE concentrations and both the number of electrical appliances and polyurethane foam-containing chairs. Concentrations of sigmaPBDE and BDEs 47 and 99 were significantly higher (p < 0.1) in omnivorous diet samples than in vegan diet samples, implying that while plant-based foods contribute appreciably, higher exposure occurs via ingestion of animal-based comestibles.     

Trends in polycyclic aromatic hydrocarbon concentrations in the great lakes atmosphere

Atmospheric polycyclic aromatic hydrocarbon (PAHs) concentrations were measured in both the vapor and particle phases at seven sites near the Great Lakes as a part of the Integrated Atmospheric Deposition Network. Lower molecular weight PAHs, including fluorene, phenanthrene, fluoranthrene, and pyrene, were dominant in the vapor phase, and higher molecular weight PAHs, including chrysene, benzo[a]pyrene, and coronene, were dominant in the particle phase. The highest PAH concentrations in both the vapor and particle phases were observed in Chicago followed by the semiurban site at Sturgeon Point, NY. The spatial difference of PAH concentrations can be explained by the local population density. Long-term decreasing trends of most PAH concentrations were observed in both the vapor and particle phases at Chicago, with half-lives ranging from 3-10 years in the vapor phase and 5-15 years in the particle phase. At Eagle Harbor, Sleeping Bear Dunes, and Sturgeon Point, total PAH concentrations in the vapor phase showed significant, but slow, long-term decreasing trends. At the Sturgeon Point site, which was impacted by a nearby city, particle-phase PAH concentrations also declined. However, most particle-phase PAH concentrations did not show significant long-term decreasing trends at the remote sites. Seasonal trends were also observed for particle-phase PAH concentrations, which were higher in the winter and lower in the summer.     

Plant uptake of atmospheric brominated flame retardants at an E-waste site in southern China

Brominated flame retardants (BFRs) were measured in eucalyptus leaves and pine needles as well as the leaf surface particles (LSPs) of the two species at an e-waste site in southern China in 2007-2008. The monthly concentrations of total BFRs in the eucalyptus leaves and pine needles were in range of 30.6-154 and 15.1-236 ng/g dry weight, respectively, and relatively higher concentrations were observed in winter and spring. Correlation analysis of BFR concentrations and comparison of PBDE compositions between the plants and LSPs, air (gaseous and particle-bound phases), and ambient variables were conducted. The results revealed that BFRs in the plants, especially for less brominated BFRs, showed positive relationships with BFRs in the LSPs and negative relationships with the gaseous BFRs and ambient temperature. The PBDE profiles in the plants were similar to the gaseous profile for low brominated BDEs (di- through hexa-BDEs) and to the LSP profiles for highly brominated BDEs (hepta- through deca-BDEs). Applying McLachlan's framework to our data suggests that the uptake of BFRs was controlled primarily by gaseous partitioning equilibrium for compounds with log octanol-air partition coefficients (K(OA)) < 12 and by particle-bound deposition for compounds with log K(OA) > 13. Different relationships between the plant/air partition coefficient (K(PA)) and K(OA), which depend on the uptake mechanisms, were observed for polybrominated diphenyl ethers (PBDEs). This paper adds to the current knowledge of the factors and mechanisms governing plant uptake of semivolatile organic compounds with relatively high K(OA) in the environment.     

Atmospheric organochlorine pesticide concentrations near the Great Lakes: temporal and spatial trends

As a part of the Integrated Atmospheric Deposition Network, atmospheric organochlorine pesticide concentrations were measured in both the gas and particle phases at seven sites near the Great Lakes. Much higher organochlorine pesticide concentrations were found in the gas phase compared to that in the particle phase. Long-term decreasing trends were observed for most pesticides in both phases. Two different seasonal trends were observed in the particle phase: (a) in-use pesticides, such as endosulfan, showed higher concentrations in the summer, a time corresponding to their agriculture use, and (b) restricted organochlorine pesticides, such as lindane, showed higher particle-phase concentrations in the winter, presumably due to their enhanced partitioning from the gas phase to particles. Generally, Chicago had the highest concentrations of chlordanes, dieldrin, and sigmaDDT, suggesting that urban areas could be sources of these compounds to atmosphere. Point Petre had the highest concentrations of endosulfan, likely due to its agricultural application in Southern Ontario.     

Results from the Lake Michigan Mass Balance study: concentrations and fluxes of atmospheric polychlorinated biphenyls and trans-nonachlor

In this paper, we summarize the data and methods used to estimate atmospheric exchange of polychlorinated biphenyls (PCBs) and trans-nonachlor with Lake Michigan. This work was conducted as part of the Lake Michigan Mass Balance (LMMB) study. For the atmospheric component of the LMMB, more than 400 gas- and particulate-phase samples were collected at eight sites on the shore around the lake (shoreline) and at 14 sites on the lake (over-water). We review the quality of the data set; describe the concentrations in atmospheric gas and particulate phases; report local, instantaneous, net gas fluxes; and estimate annual deposition of the particle-associated compounds. The quality of the data set is high except for a subset of over-water samples where PCB contamination is suspected. Gas-phase trans-nonachlor concentrations (although not the resulting gas fluxes) are inversely correlated with latitude and positively correlated with temperature. Gas-phase sigmaPCBs (sum of 98 congener groups) are highest in concentration at the Chicago site and lowest at the Sleeping Bear Dunes site. The resulting sigmaPCB gas fluxes exhibit a seasonality that reflects elevated summertime gas-phase concentrations not compensated by temperature-corrected Henry's law coefficients. Particulate-phase deposition is much smaller in magnitude than gas fluxes, for either compound. Gas and particulate fluxes are comparable only at the Chicago site and only when large (> 10 microm) particulates are considered.     

Discontinued and alternative brominated flame retardants in the atmosphere and precipitation from the great lakes basin

Air (vapor and particle) and precipitation samples were collected at five sites (two urban, one rural, and two remote) around the Great Lakes during 2005-2009 as a part of the Integrated Atmospheric Deposition Network (IADN). The concentrations of polybrominated diphenyl ethers (PBDEs), decabromodiphenylethane (DBDPE), hexabromobenzene (HBB), pentabromoethylbenzene (PBEB), and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) were measured in these samples. The highest concentrations of these compounds were generally observed at the two urban sites-Chicago and Cleveland-with a few exceptions: The remote site at Eagle Harbor had particularly high levels of PBEB in all three phases, and the rural Sturgeon Point site had the highest HBB concentrations in the vapor phase. The sources of HBB and PBEB to these sites are unknown. A multiple linear regression model was applied to the concentrations of these compounds in the vapor phase, particle phase, precipitation, and the three phases combined. This regression resulted in overall (three phases combined) halving times for total PBDE concentrations of 6.3 ± 1.1 years. The overall halving times for HBB and BTBPE were 9.5 ± 4.6 years and 9.8 ± 2.8 years, respectively. For PBEB and DBDPE, the regression was not statistically significant for the combined phases, indicating that the atmospheric concentrations of these compounds have not changed between 2005 and 2009.     

Diastereoisomer- and enantiomer-specific profiles of hexabromocyclododecane in the atmosphere of an urban city in South China

Hexabromocyclododecanes (HBCDs) are ubiquitous contaminants in the environment, but little is known on the occurrence and distribution of HBCDs in the background atmosphere of urban environments. In this study, air samples were collected from four sites in the city of Guangzhou, a typical fast developing metropolitan of South China, for quantifying the concentration levels, diasteroisomer profiles, gas-particle distribution and enantiomeric fractions of HBCDs. The results showed that the measured mean atmospheric HBCD concentrations ranged from 0.69 to 3.09 pg/m3, which were similar to those reported from remote or urban sites of the U.S., but were significantly lower than those of Europe. The analysis on diastereoisomer profiles indicated that alpha-HBCD (59--68%) was the dominant isomer and beta-HBCD was a minor isomer in all air samples, which appeared to be different from commercial products. A large variable percentage of HBCDs (69.1--97.3%) are existed in the particle phase, suggesting that long-range tansport of HBCDs might be occur in some environmental conditions. The results of enantiomeric fractions indicated that beta- and gamma-HBCD were racemic mixtures in the tested air samples and that (--)-alpha-HBCD was slightly enriched in the typical urban site, implying that the HBCDs in these studied sites might be a mixture of emissions from both local sources and soil-air exchange.     

Atmospheric atrazine at Canadian IADN sites

Atrazine is one of the most widely used herbicides in North America and has been primarily applied to corn production in the Great Lakes basin for over 30 years. During 1996-2002, atrazine concentrations in the atmospheric gas and particle phases were investigated at three Canadian Integrated Atmospheric Deposition Network (IADN) sites including two lakeside sites (Burnt Island and Point Petre) and a rural inland site (Egbert). Strong seasonality with peak concentrations occurring in late April-early July was observed. An atrazine usage map for Canada (sum: 870 t) and the United States (sum: 34 500 t) in 2002 was created. Local application and regional atmospheric transport both appear to contribute to its atmospheric occurrence, while the latter might episodically result in high concentrations events. No strong temperature dependence was observed for atrazine particle-gas partitioning. Recent measurement results of atrazine in precipitation samples collected at Egbert and another agricultural site, Vineland, through the Canadian Atmospheric Network for Currently Used Pesticides (CANCUP), are also presented, Dry, wet, and gas exchange deposition all contribute to atmospheric inputs of atrazine to the Great Lakes. For Lake Ontario, gas exchange is estimated to be of similar magnitude to dry and wet deposition.     

Dechlorane plus in the atmosphere and precipitation near the Great Lakes

Air (vapor and particle) and precipitation samples were collected at five sites (two urban, one rural, and two remote) on the shores of the Great Lakes from January 1, 2005 to December 31, 2009 as a part of the Integrated Atmospheric Deposition Network (IADN). The concentrations of the syn and anti isomers of Dechlorane Plus (DP), a highly chlorinated flame retardant, were measured in these samples. The highest concentrations of these compounds were generally observed at the rural site at Sturgeon Point, New York, which is located near DP's manufacturing facility in Niagara Falls, New York, and at the urban site at Cleveland, Ohio. A multiple linear regression model was applied to the concentrations of these compounds in the vapor phase, particle phase, precipitation, and for the three phases combined. This regression resulted in an overall (three phases combined) doubling time for the anti-DP isomer of 9.5 ± 3.6 years, but for the syn- and total DP (syn + anti) concentrations, the overall regression was not statistically significant. These results suggest that there has been no significant change in the atmospheric concentrations of these compounds over the 2005-2009 time period. The effect of distance from the source in Niagara Falls was highly significant; for example, doubling the distance from Niagara Falls decreased the DP concentrations by about 30%. The effect of the number of people living and working within a 25-km radius of the sampling site (population density) was also highly significant but small; for example if this population doubled or halved, then the atmospheric DP concentrations would increase or decrease by only a few percent.     

Brominated flame retardants in the atmosphere of E-waste and rural sites in southern China: seasonal variation, temperature dependence, and gas-particle partitioning

The recycling of electrical and electronic waste(e-waste) in developing countries has attracted much attention as a significant source of brominated flame retardants (BFRs).Gaseous and particle-bound BFRs were measured in the atmosphere at e-waste and rural sites in southern China during 2007-2008. The annual average concentrations in the air were 3260 ± 3370 and 219 ± 192 pg/m3 for polybrominated diphenyl ethers (PBDEs) and were 546 ± 547 and 165 ± 144 pg/m3 for non-PBDE BFRs at the e-waste and rural sites,respectively. PBDEs had unusually high relative concentrations of di- and tribrominated congeners at the e-waste site. The Clausius-Clapeyron (CC) plots showed that the gaseous concentrations of less brominated BFRs (di- through hexa-BFRs) were strongly controlled by temperature-driven evaporation from contaminated surfaces (e.g., e-waste, soils, and recycled e-waste remains) except for winter. However, weak temperature dependence at the rural site suggests that regional or long-range atmospheric transport was largely responsible for the air concentrations. Gas-particle partitioning (KP) of PBDEs correlated well with the subcooled liquid vapor pressure (PL(o)) for most sampling events. The varied slopes of log KP versus log PL(o) plots for the e-waste site (-0.59 to -1.29) indicated an influence of ambient temperature and atmospheric particle properties on the partitioning behavior of BFRs. The flat slopes (-0.23 to -0.80) for the rural site implied an absorption-dominant partitioning. This paper suggests that e-waste recycling in Asian low-latitude regions is a significant source of less brominated BFRs and has important implications for their global transport from warm to colder climate     

Atmospheric concentrations and deposition of polycyclic aromatic hydrocarbons to the Mid-Atlantic East Coast region

Atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) were measured at urban/industrial, suburban, coastal, and rural areas in New Jersey as part of the New Jersey Atmospheric Deposition Network. Concentrations of 36 PAH compounds were measured in the gas and particle phases in air and in precipitation at nine sites at regular intervals from October 1997 through May 2001. Gas-phase and particle-phase sigma36PAH concentrations ranged from 0.45 to 118 ng m(-3) and from 0.046 to 172 ng m(-3), respectively, and precipitation concentrations ranged from 11 to 16200 ng L(-1). PAH concentrations vary spatially across the region, with the highest concentrations occurring at the most heavily urban and industrial locations. Average gas absorption deposition ranged from 0.004 (naphthacene) to 5040 (methylphenanthrenes) ng m(-2) d(-1), and dry particle deposition PAH fluxes ranged from 0.11 (naphthacene) to 300 (benzo[b+k]fluoranthene) ng m(-2) d(-1) at the nine sites. Average atmospheric wet deposition PAH fluxes at the seven sites ranged from 0.40 (cyclopenta[cd]pyrene) to 140 (methylphenanthrenes) ng m(-2) d(-1). These represent the first comprehensive estimates of PAH deposition to New Jersey and the Mid-Atlantic East Coast.     

Higher accumulation of polybrominated diphenyl ethers in infants than in adults

Pooled serum samples collected from 8132 residents in 2002/ 03 and 2004/05 were analyzed to assess human polybrominated diphenyl ether (PBDE) concentrations from specified strata of the Australian population. The strata were defined by age (0-4 years, 5-15 years, < 16 years, 16-30 years, 31-45 years, 46-60 years, and > 60 years); region; and gender. For both time periods, infants and older children had substantially higher PBDE concentrations than adults. For samples collected in 2004/ 05, the mean +/- standard deviation sigmaPBDE (sum of the homologue groups for the mono-, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona-, and deca-BDEs) concentrations for 0-4 and 5-15 years were 73 +/- 7 and 29 +/- 7 ng g(-1) lipid, respectively, while for all adults > 16 years, the mean concentration was lower at 18 +/- 5 ng g(-1) lipid. A similar trend was observed for the samples collected in 2002/03, with the mean sigmaPBDE concentration for children < 16 years being 28 +/- 8 ng g(-1) lipid and for the adults >16 years, 15 +/- 5 ng g(-1) lipid. No regional or gender specific differences were observed. Measured data were compared with a model that we developed to incorporate the primary known exposure pathways (food, air, dust, breast milk) and clearance (half-life) data. The model was used to predict PBDE concentration trends and indicated that the elevated concentrations in infants were primarily due to maternal transfer and breast milk consumption with inhalation and ingestion of dust making a comparatively lower contribution.     

Atmospheric mercury in the Lake Michigan basin: influence of the Chicago/Gary urban area

The relative importance of the Chicago/Gay urban area was investigated to determine its impact on atmospheric mercury (Hg) concentrations and wet deposition in the Lake Michigan basin. Event wet-only precipitation, total particulate, and vapor phase samples were collected for Hg, and trace element determinations from five sites around Lake Michigan from July 1994 through October 1995 as part of the Lake Michigan Mass Balance Study (LMMBS). In addition, intensive over-water measurements were conducted aboard the EPA research vessel Lake Guardian during the summer of 1994 and the winter of 1995 as part of the Atmospheric Exchange Over Lakes and Oceans Study. Atmospheric Hg concentrations were found to be significantly higher in the Chicago/Gary urban area than surrounding sites: Hg in precipitation was a factor of 2 and particulate Hg was a factor of 6 times higher. Overwater measurements found elevated Hg concentrations 19 km off shore of Chicago/Gary suggesting an enhanced near field atmospheric deposition to Lake Michigan. Meteorological transport analyses also determined that local sources in the Chicago/Gary urban area significantly impacted all of the LMMBS sites indicating a broad impact to the entire Lake Michigan basin.     

Persistent organic pollutants at the base of the Antarctic marine food web

Various organochlorine pesticides and brominated diphenyl ethers (BDE-47, -99, and -100) were measured in sea ice algae, water column plankton, and juvenile and adult krill collected in the Palmer Long-Term Ecological Research (LTER) region west of the Antarctic Peninsula during late austral winter and midsummer, 2001-2002. BDEs were 100-1000 times higher in ice algae and 2-10 times higher in phytoplankton than the most abundant organochlorine pesticide, hexachlorobenzene (HCB), reflecting the current production and use of BDEs versus organochlorine pesticides. However, concentrations of HCB and BDEs were significantly lower in summer plankton than in ice algae indicating lower atmospheric inputs, removal from the water column, and/or biodilution of persistent organic pollutants at the base of the food web during summer. Concentrations of HCB (juvenile and adult krill) and BDEs (juvenile krill) were not significantly different from their primary food source (ice algae, phytoplankton), and BDEs were significantly lower in adult krill versus phytoplankton, indicating no biomagnification of HCB or BDEs during transfer from plankton to krill. The high concentrations of BDEs and HCB in ice algae and associated juvenile krill illustrate the importance of sea ice as a vector for entry of POPs into the Antarctic marine ecosystem.     

Temporal development of brominated flame retardants in peregrine Falcon (Falco peregrinus) eggs from South Greenland (1986-2003)

A time trend between 1986 and 2003 was found for brominated flame retardants in peregrine falcon eggs from South Greenland, with significantly increasing concentrations of the polybrominated diphenyl ethers (PBDEs) 99, 100, 153, 154, and 209. For BDE-99 and -100, the concentration increased approximately 10% per year. The concentrations of PBDEs were among the highest detected in wildlife so far and ranged from 300 to 12,900 ng/g lipid weight (lw) for sigmaPBDE. While tetrabromobisphenol A (TBBPA) was below the limit of detection in all eggs, hexabromocyclododecane (HBCD), dimethyl-TBBPA, and brominated biphenyl BB-153 were detected in a majority of eggs, with median concentrations of 2.4, 230, and 550 ng/g lw, respectively. Analyses of eggs of the same bird showed no significant intra-clutch variation for PBDEs, BB-153, and HBCD but larger variations for dimethyl-TBBPA. Inter-clutch variations with increasing time trends exist for the BDEs 99, 100, 153, 154, and 209, while a decreasing contamination with the BDEs 183, 49, 47, 66 and 153 was indicated in a subset of eggs.     

Dechlorane plus, a chlorinated flame retardant, in the Great Lakes

A highly chlorinated flame retardant, Dechlorane Plus (DP), was detected and identified in ambient air, fish, and sediment samples from the Great Lakes region. The identity of this compound was confirmed by comparing its gas chromatographic retention times and mass spectra with those of authentic material. This compound exists as two gas chromatographically separable stereoisomers (syn and anti), the structures of which were characterized by one- and two-dimensional proton nuclear magnetic resonance. DP was detected in most air samples, even at remote sites. The atmospheric DP concentrations were higher at the eastern Great Lakes sites (Sturgeon Point, NY, and Cleveland, OH) than those at the western Great Lakes sites (Eagle Harbor, MI, Chicago, IL, and Sleeping Bear Dunes, MI). Atthe Sturgeon Point site, DP concentrations once reached 490 pg/m3. DP atmospheric concentrations were comparable to those of BDE-209 at the eastern Great Lakes sites. DP was also found in sediment cores from Lakes Michigan and Erie. The peak DP concentrations were comparable to BDE-209 concentrations in the sediment core from Lake Erie butwere about 30 times lower than BDE-209 concentrations in the core from Lake Michigan. In the sediment cores, the DP concentrations peaked around 1975-1980, and the surficial concentrations were 10-80% of peak concentrations. Higher DP concentrations in air samples from Sturgeon Point, NY, and in the sediment core from Lake Erie suggest that DP's manufacturing facility in Niagara Falls, NY, may be a source. DP was also detected in archived fish (walleye) from Lake Erie, suggesting that this compound is, at least partially, bioavailable.     

Hexabromocyclododecanes in surface soils from E-waste recycling areas and industrial areas in South China: concentrations, diastereoisomer- and enantiomer-specific profiles, and inventory

Hexabromocyclododecanes (HBCDs) are raising concern because of their potential persistence, bioaccumulation, and toxicity. In this study, we investigated the concentrations, diastereoisomer- and enantiomer-specific profiles, and mass inventories of HBCDs in 90 surface soils from two e-waste recycling areas (Qingyuan, Guiyu) and from industrial areas in South China. The mean concentrations of total HBCDs in the surface soils ranged from 0.22 to 0.79 and from 0.31 to 9.99 ng/g dw for two surrounding e-waste recycling sites and industrial areas, respectively. The highest total HBCD concentration (284 ng/g dw) was found at the e-waste recycling site in Qingyuan, while total HBCD levels fell dramatically with increasing distance from the recycling site, suggesting that the e-waste recycling activities were an important source of HBCDs. The diastereoisomer profiles in 75 of the 90 soil samples differed from those of the commercial products. The mean enantiomeric fraction values for α-, β-, and γ-HBCDs in soils ranged from 0.503(0.010) to 0.507(0.003), 0.494(0.003) to 0.506(0.009), and 0.502(0.003) to 0.511(0.006), respectively, suggesting that there was no stereoselective transformation of the three diastereoisomers. The mass inventories of HBCDs gave preliminarily estimates of 3.42 kg and 1.84 tonnes for the e-waste recycling areas and industrial areas, respectively. It is notable that the diasteroisomer and enantiomer profiles of this study failed to distinguish definitely that the isomeric transformation occurred during the product processing or in the environmental matrix. Further laboratory studies on abiotic and biotic transformation are needed to clarify this issue.     

Temporal trends of polychlorinated biphenyls in precipitation and air at chicago

Polychlorinated biphenyl (PCB) concentrations in precipitation (1997-2003) and in the atmospheric gas phase (1996-2003) collected in Chicago, IL, are reported. These data were obtained as part of the Integrated Atmospheric Deposition Network. For comparison, PCB concentrations at a remote site, Sleeping Bear Dunes on the northeastern shore of Lake Michigan, are also reported. Much higher PCB concentrations in both precipitation (7.1 +/- 0.9 ng/L) and the gas phase (1.4 +/- 0.1 ng/m3) at Chicago compared to Sleeping Bear Dunes (1.1 +/- 0.1 ng/L and 0.1 +/- 0.08 ng/m3, respectively) indicate that Chicago is a source of PCBs to the Great Lakes. A long-term decreasing trend of PCB concentrations in precipitation was observed at Chicago with a half-life of 6.8 +/- 3.1 years. The corresponding half-life for PCB concentrations in the gas phase was 7.7 +/- 1.1 years. The significant long-term decrease of PCB concentrations in precipitation and the gas phase in Chicago suggests that regulatory efforts are working, at least in this city.