An Asia-specific source of dechlorane plus: concentration, isomer profiles, and other related compounds

The distribution of dechloranes, a group of chlorinated flame retardants, were investigated in air, soil, and sediment around a newly discovered Dechlorane Plus (DP) production facility in China (Anpon). To date, the only known DP manufacturing plant is located in Niagara Falls, NY (OxyChem). Dechloranes including DP, Dechlorane (Mirex), and the recently discovered Dechlorane 602 (Dec 602) were detected in air, soil, and sediment, while Dechlorane 603 and Dechlorane 604 were below detection limit in all matrices. DP air concentrations near the facility ranged from 7737 to 26 734 pg m(-3), the greatest reported thus far. Soil concentrations in the same area for DP, Dechlorane, and Dec 602 were 1490+/-3580 ng g(-1), 81.6+/-96.5 ng g(-1), and 7.24+/-13.2 ng g(-1) dry weight, respectively. Interestingly, lower concentrations of DP (4.93+/-4.34 ng g(-1)), Dechlorane (30.2+/-19.9 ng g(-1)), and Dec 602 (2.14+/-2.23 ng g(-1)) were found in sediment from a nearby canal. Spatial trends of Dechlorane and Dec 602 in soil were similar to DP, implying that the DP manufacturing plant may also be a source of these other flame retardants. DP soil concentrations surrounding the facility decreased by an order of magnitude within 7.5 km. The syn-DP fractional abundance (fsyn) value (0.40) for the commercial DP product manufactured at Anpon was slightly higher than that (0.20-0.36) produced by OxyChem. The fsyn value in most air samples was largely similar to the Chinese commercial DP mixture, while most soil and sediment abundances were lower, suggesting a stereoselective depletion of syn-DP.

Spatial distribution of hexabromocyclododecanes (HBCDs), polybrominated diphenyl ethers (PBDEs) and organochlorines in bivalves from Japanese coastal waters

In order to elucidate the spatial distribution of brominated flame retardants (BFRs) in the Japanese coastal environment, hexabromocyclododecanes (HBCDs), polybrominated diphenyl ethers (PBDEs) and organochlorines (OCs: PCBs, DDTs, CHLs, HCHs, HCB) were determined in bivalves (oysters and mussels) collected from Japanese coastal waters. HBCDs and PBDEs were detected in all samples analyzed. Concentration ranges of HBCDs were 12-5200 ng g(-1) lipid wt., followed by PCBs (20-3100 ng g(-1))>PBDEs (3.1-86 ng g(-1) lipid wt.). The highest concentration of HBCDs was found in the Osaka region. This result indicates that HBCDs are ubiquitous and predominant compounds in bivalves from the Japanese coastal waters. Since no species differences between oysters and mussels were observed for the bioaccumulation properties of HBCDs and PBDEs, oysters could be utilized for BFR contamination monitoring worldwide as an alternative to mussels. Global comparisons between oysters and mussels showed that HBCD concentrations in Japan are among the highest levels reported from Asia and Europe. Estimated dietary exposures of HBCDs and PBDEs through seafood were 0.45-34 ng kg body weight(-1)d(-1), and 0.054-6.8 ng kg body weight(-1)d(-1), respectively. These exposure levels were more than 1000 times lower than the lowest observable effects or no observable adverse effects levels for HBCDs and PBDEs, respectively.

Quantitative analysis of volatile methylsiloxanes in waste-to-energy landfill biogases using direct APCI-MS/MS

Landfill-biogas utilization is a win-win solution as it creates sources of renewable energy and revenue while diminishing greenhouse gas emissions. However, the combustion of a siloxane-containing biogas produces abrasive microcrystalline silica that causes severe and expensive damages to power generation equipment. Hence, the importance of siloxane analysis of the biogas has increased with the growth of the waste-to-energy market. We have investigated an improved method for the analysis of octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) in biogas using deuterated hexamethyldisiloxane (HMDS-d(18)) as an internal standard with direct atmospheric pressure chemical ionization/tandem mass spectrometry (APCI-MS/MS). The use of HMDS-d(18) as a single internal standard provided effective signal compensation for both D4 and D5 in biogas and improved the sensitivity and reliability for the direct APCI-MS/MS quantification of these compounds in biogas. Low detection limits ( approximately 2 microg/m(3)) were achieved. The method was successfully applied for the determination of D4 and D5 contents in various samples of biogas recovered for electrical power generation from a landfill site in Montreal. Concentrations measured for D4 and D5 were in the ranges of 131-1275 and 250-6226 microg/m(3), respectively. Among the various landfill zones sampled, a clear trend of decreasing D4 and D5 concentrations was observed for older landfill materials.

Direct analysis of volatile methylsiloxanes in gaseous matrixes using atmospheric pressure chemical ionization-tandem mass spectrometry

Atmospheric pressure chemical ionization-tandem mass spectrometry (APCI-MS/MS) was applied for the first time to the direct analysis of octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) in gaseous matrixes without extraction or prior chromatographic separation. Mass spectrometric characteristics of both compounds under APCI conditions and their fragmentation behavior in MS/MS were investigated. Unlike the classical gas chromatography/mass spectrometry (GC/MS), which involves solvent extraction before gas chromatography, the proposed approach prevents contamination from GC system components and provides unambiguous structural assignments. The method performs well achieving good linearity (R(2) > 0.997), low limits of detection (4-6 microg/m(3)), good precision (RSD < 10%) and accuracy (>93%), and a wide dynamic range. Its applicability to real-world samples was evaluated through measurements of D4 and D5 concentrations in air and biogas samples. The high sensitivity, selectivity, and reliability of this method render our approach a good alternative to the commonly used GC/MS method.

Polybrominated diphenyl ethers and their hydroxylated analogs in plasma of bottlenose dolphins (Tursiops truncatus) from the United States east coast

Polybrominated diphenyl ethers (PBDEs) and hydroxylated PBDEs (OH-PBDEs) were determined in plasma of free-ranging bottlenose dolphins (Tursiops truncatus) from Charleston (CHS), South Carolina, and the Indian River Lagoon (IRL), Florida, U.S.A. Significantly lower sums (sigma) of PBDE concentrations (sum of 12 congeners) were found in animals from the IRL (arithmetic mean, 5.45 +/- 4.63 ng/g wet wt) compared with those from CHS (30 +/- 40 ng/g wet wt). Brominated diphenyl ether (BDE)-47 was the predominant PBDE in dolphins from the IRL (50% of the sigma PBDEs) and CHS (58%). The sigma PBDE concentrations in plasma of dolphins were negatively correlated with age at both locations. Fifteen and sixteen individual OH-PBDE congeners could be quantified in plasma of dolphins from IRL and CHS, respectively. Similar to sigma PBDE, mean sigma OH-PBDE concentrations were significantly higher in plasma of dolphins at CHS (1150 +/- 708 pg/g wet wt) compared with those at IRL (624 +/- 393 pg/g wet wt). The predominant congener at both locations was 6-OH-PBDE-47 (IRL, 384 +/- 319 pg/g wet wt; CHS, 541 +/- 344 pg/g wet wt), representing 61.5% of total sigma OH-PBDE at IRL and 47.0% at CHS. Concentrations of sigma OH-PBDEs were weakly negatively correlated with age in dolphins from both locations (p < 0.05; IRL, r2 = 0.048; CHS, r2 = 0.021). In addition to the OH-PBDE congeners identified with technical standards, eight and four unidentified OH-PBDEs were detected and quantified, respectively, in animals from CHS (sum of unidentified OH-PBDEs = 1.35 +/- 0.90 pg/g wet wt) and IRL (0.73 +/- 0.40 pg/g wet wt). Results of the present study suggest that, unlike OH-PCBs, OH-PBDEs in bottlenose dolphins are minor products in plasma relative to sigma PBDEs and a significant proportion may be a consequence of the dietary uptake of naturally produced methoxylated- and OH-PBDEs.

Occurrence of triclosan in plasma of wild Atlantic bottlenose dolphins (Tursiops truncatus) and in their environment

The presence of triclosan, a widely-used antibacterial chemical, is currently unknown in higher trophic-level species such as marine mammals. Blood plasma collected from wild bottlenose dolphins (Tursiops truncatus) in Charleston, SC (CHS) (n = 13) and Indian River Lagoon, FL (IRL) (n = 13) in 2005 was analyzed for triclosan. Plasma concentrations in CHS dolphins ranged from 0.12 to 0.27 ng/g wet weight (mean 0.18 ng/g), with 31% of the sampled individuals having detectable triclosan. The mean IRL dolphin plasma concentrations were 0.072 ng/g wet weight (range 0.025-0.11 ng/g); 23% of the samples having detectable triclosan. In the CHS area, triclosan effluent values from two WWTP were both 190 ng/L and primary influents were 2800 ng/L and 3400 ng/L. Triclosan values in CHS estuarine surface water samples averaged 7.5 ng/L (n = 18) ranging from 4.9 to 14 ng/L. This is the first study to report bioaccumulation of anthropogenic triclosan in a marine mammal highlighting the need for further monitoring and assessment.

Fractionation and bioaccumulation of perfluorooctane sulfonate (PFOS) isomers in a Lake Ontario food web

The environmental ubiquity of perfluorooctane sulfonate (PFOS) is well-known. However, little is known about the environmental fate of individual PFOS isomers. In this study, we investigated the fractionation and the bioaccumulation of PFOS isomers in water, sediment and biota collected from Lake Ontario. A total of six isomers, three perfluoro-monomethyl-substituted compounds, and three perfluoro-dimethyl isomers in addition to the linear PFOS (L-PFOS) were detected in water, sediment and biota. L-PFOS represented a much higher proportion of total PFOS (sum of linear and branched) in all organisms (>88%) compared to its proportion in technical PFOS (77%). The predominance of L-PFOS suggests a reduced uptake of branched isomers, a more rapid elimination of the branched isomers and/or a selective retention of the L-PFOS. The PFOS isomer profile found in biota was very similar to sediment, even for pelagic organisms such as zooplankton, suggesting greater partitioning of L-PFOS to biota and to sediment. The bioaccumulation factor (BAF) for L-PFOS between lake trout (whole fish) and water was estimated to be 3.4 x 10(4) L/kg compared with 2.9 x 10(3) L/kg for the monomethyl-substituted group (MM-PFOS). The remarkable difference between L-PFOS and branched isomer BAFs is due to an enrichment of branched isomers in water. The trophic magnification factor of L-PFOS (4.6 +/- 1.0) was greater than MM-PFOS isomers (1.3 +/- 0.17 to 2.6 +/- 0.51), whereas dimethyl-PFOS showed no biomagnification. The results illustrate the important influence of molecular structure on the bioaccumulation of perfluoroalkyl sulfonates.

Polymeric brominated flame retardants: are they a relevant source of emerging brominated aromatic compounds in the environment?

A purge and trap method was used to study the release of brominated organic compounds from polymeric brominated flame retardants (BFRs), a relatively unknown class of flame retardant materials. Among the volatile brominated organics released, pentabromotoluene (PBTo), pentabromoethylbenzene (PBEB), and hexabromobenzene (HBB) were of particular interest because of their high potential to persist in the environment The impact of a thermal stress on the release of these compounds was assessed by applying different constant temperatures for one hour to a polymeric BFR sample. Release rates ranged between 22 +/- 2.1 ng g(-1) h(-1) for PBEB to 2480 +/- 500 ng g(-1) h(-1) for PBTo at room temperature. These rates of release reached 65 +/- 11 ng g(-1) h(-1) for PBEB and 42400 +/- 4700 ng g(-1) h(-1) for PBTo at 100 degrees C. This suggests that the compounding of thermoplastic polyesters done at high temperatures, up to 290 degrees C, could lead to the release of significant amounts of volatile brominated compounds in the environment when crude polymeric BFRs are used as flame retardants. To assess if this unsuspected source of volatile brominated compounds to the environment was relevant to support air concentrations in the Great Lakes area, air samples collected at Egbert (ON, Canada) were analyzed and PBTo, PBEB, and HBB were detected at low levels in some air samples (<0.01 to 0.09 pg/m3). As a second step, a Level III fugacity model was run using release rates of PBTo, PBEB, and HBB determined in this study. Results of the model indicated that prevailing PBEB and HBB air concentrations were not supported by their release from polymeric BFRs but by the use of these compounds as additive BFRs. However, these model predictions suffered from a lack of information on the actual use of polymeric BFRs. Hence, further work is needed to assess the release of potentially persistent brominated aromatic compounds from polymeric BFRs.

Global contamination of coplanar polybrominated/chlorinated biphenyls (Co-PXBs) in the market fishes from Japan

Polybrominated chlorinated biphenyls (PXBs, X=Br, Cl) are a group of environmental contaminants that have not been studied previously. The introduction of the second halogen to the biphenyl backbone increases the number of possible congeners to more than 9000. Only a limited number of PXBs are commercially available. In order to determine the occurrence of these compounds in environmental matrices, an isotope dilution HRGC/HRMS method for determination of five co-planar polybrominated/chlorinated biphenyls (Co-PXBs) in biota was developed. The method detection limit for these compounds ranged between 0.05 and 0.5 pg/g for 4'-monobromo-3,3',4,5-tetrachlorobiphenyl and 3',4',5'-tribromo-3,4-dichlorobiphenyl, respectively. Concentrations of five co-planar polybrominated and chlorinated biphenyls in eighteen different fish fillets from Japanese markets ranged between 4 and 46 pg/g wet weight for mink whale and young yellow-tail fish. These values are substantially lower than those reported for Co-PCBs; however, it should be noted that due to the unavailability of standards, identification and quantification of all the isomers was not possible.

Biotransformation enzymes and thyroid axis disruption in juvenile rainbow trout (Oncorhynchus mykiss) exposed to hexabromocyclododecane diastereoisomers

Juvenile rainbow trout (Oncorhynchus mykiss) were fed either a reference diet or one of three diets enriched with alpha, beta, or gamma diastereoisomers of hexabromocyclododecane (HBCD, C12H18Br6) for 56 days. This exposure period was followed by 112 days during which all fish were fed the reference diet. Potential effects of HBCD on phase I and II biotransformation enzyme activities and thyroid axis disruption were examined. Disruption of the thyroid axis was most evident in the gamma-HBCD exposed group, as indicated by lower circular FT4 and higher FT3 as well as an increase in thyroid epithelial cell height. However, fish fed the alpha-HBCD enriched diet also exhibited altered glucuronyltransferase activity and thyroid epithelial cell heights and the beta-HBCD group had altered FT4 and FT3 and glucuronyltransferase activity. T4ORD activity was not affected after 14 days, but was significantly lower among all HBCD exposed fish compared to the reference fish after 56 days. Results from these experiments indicate that all isomers have the potential to disrupt thyroid homeostasis.

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

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

Major structural components in freshwater dissolved organic matter

Dissolved organic matter (DOM) contains a complex array of chemical components that are intimately linked to many environmental processes, including the global carbon cycle, and the fate and transport of chemical pollutants. Despite its importance, fundamental aspects, such as the structural components in DOM remain elusive, due in part to the molecular complexity of the material. Here, we utilize multidimensional nuclear magnetic resonance spectroscopy to demonstrate the major structural components in Lake Ontario DOM. These include carboxyl-rich alicyclic molecules (CRAM), heteropolysaccharides, and aromatic compounds, which are consistent with components recently identified in marine dissolved organic matter. In addition, long-range proton-carbon correlations are obtained for DOM, which support the existence of material derived from linear terpenoids (MDLT). It is tentatively suggested that the bulk of freshwater dissolved organic matter is aliphatic in nature, with CRAM derived from cyclic terpenoids, and MDLT derived from linear terpenoids. This is in agreement with previous reports which indicate terpenoids as major precursors of DOM. At this time it is not clear in Lake Ontario whether these precursors are of terrestrial or aquatic origin or whether transformations proceed via biological and/ or photochemical processes.

Time-weighted average water sampling in Lake Ontario with solid-phase microextraction passive samplers

In this study, three types of solid-phase microextraction (SPME) passive samplers, including a fiber-retracted device, a polydimethylsiloxane (PDMS)-rod and a PDMS-membrane, were evaluated to determine the time weighted average (TWA) concentrations of polycyclic aromatic hydrocarbons (PAHs) in Hamilton Harbor (the western tip of Lake Ontario, ON, Canada). Field trials demonstrated that these types of SPME samplers are suitable for the long-term monitoring of organic pollutants in water. These samplers possess all of the advantages of SPME: they are solvent-free, sampling, extraction and concentration are combined into one step, and they can be directly injected into a gas chromatograph (GC) for analysis without further treatment. These samplers also address the additional needs of a passive sampling technique: they are economical, easy to deploy, and the TWA concentrations of target analytes can be obtained with one sampler. Moreover, the mass uptake of these samplers is independent of the face velocity, or the effect can be calibrated, which is desirable for long-term field sampling, especially when the convection conditions of the sampling environment are difficult to measure and calibrate. Among the three types of SPME samplers that were tested, the PDMS-membrane possesses the highest surface-to-volume ratio, which results in the highest sensitivity and mass uptake and the lowest detection level.

Detection of hydroxylated polychlorinated biphenyls (OH-PCBs) in the abiotic environment: surface water and precipitation from Ontario, Canada

Hydroxylated PCBs (OH-PCBs) are well-known metabolites of PCBs in organisms, but there has been no direct study of their presence in the abiotic environment. In this study, OH-PCBs were determined in samples of rain, snow, and surface waters from sites in Ontario, Canada. OH-PCBs were quantified by gas chromatography with high-resolution mass spectrometry (GC-HRMS)in order to provide complete characterization of all OH-PCB homolog groups. OH-PCBs and PCBs were detected in all the samples analyzed, although half of the sigmaOH-PCBs could not be identified even with 71 individual congener standards. Total concentrations of OH-PCBs (sigmaOH-PCBs) in water ranged from 0.87 to 130 pg/L and from 230 to 990 pg/g in particulate organic matter. Total fluxes of those compounds in snow and rain were from < 1 to 100 pg/m2 and from < 1 to 44 pg/ m2/day, respectively. Higher sigmaOH-PCB fluxes in rain were found in southern Ontario than in a remote north-central Ontario site possibly reflecting greater sources of precursor PCBs near urban areas. Relatively higher sigmaOH-PCB concentrations were found in surface waters from sites near sewage treatment plant (STP) outfalls in the cities of Toronto (130 pg/L) and Hamilton (35 pg/L) than in offshore samples from Lake Ontario (1.6 pg/L). The results indicate that STPs are one of the sources of OH-PCBs for lake waters in this region. Similar homolog and congener profiles in rain and offshore surface water samples suggest that atmospheric deposition is the predominant source at offshore sites. This is the first report to detect the OH-PCBs in the abiotic environment.

Sample storage and extraction efficiencies in determination of polycyclic and nitro musks in sewage sludge

Analytical technology is continuously improving, developing better methods for isolating and concentrating trace compounds in environmental samples. Polycyclic and nitro musks (PNMs) are one group of emerging trace compounds detected in municipal wastewater. Differences in sample storage, preparation, and extraction methods for their measurement have led to variability in results. We analyzed 11 PNMs by GC/MS and compared the results of different storage times and extraction methods (supercritical fluid (SFE) or microwave-assisted (MAE)) for 202 samples of primary sludge, waste activated sludge (WAS), raw sludge, and aerobically/anaerobically digested biosolids collected from Canadian municipal wastewater treatment plants. Sixty-three air-dried samples were extracted by SFE, and 139 air-dried, centrifuged, or filtered samples were extracted by MAE. The mean surrogate recoveries were 89% (standard deviation (SD)=11%) for d(10)-anthracene by SFE and 88% (SD=14%) for d(10)-phenanthrene by MAE. Storage study results showed that PNM concentrations changed by a mean of 7% and 9% for primary sludge and WAS respectively after four weeks and decreased up to 25% after 13.5 months of storage in amber glass containers at -18 degrees C. Air-drying of sludge at room temperature caused losses of about 50% of PNM concentrations compared to centrifugation. The proportions of PNMs present in the liquid phase of sludge samples were less than 5% compared to proportions in the sludge solids. The most complete liquid-solid separation was achieved by filtration of frozen/thawed sludge samples, producing a liquid phase that contained less than 1% of the total musk content of the sample.

Time-weighted average water sampling with a diffusion-based solid-phase microextraction device

A new diffusion-based solid-phase microextraction (SPME) time-weighted average (TWA) field water sampling device was developed and investigated by field trial. The sampler is constructed with copper tube and caps and a commercial SPME fiber assembly. The device possesses all advantages of SPME; it is solvent-free, reusable, combines sampling, isolation and enrichment into one step, and the fiber can be directly injected into a gas chromatograph for analysis with a commercial SPME fiber holder, without further treatment. Field trials in Laurel Creek (Waterloo, Ont., Canada) and Hamilton Harbour (Hamilton, Ont., Canada) illustrated that the device is durable, easy to deploy, and the mass uptake of the device is independent of the face velocity. The device provides good precision [relative standard deviations (RSDs) are less than 20%] and the data obtained with this device are quite comparable to those obtained with the spot sampling method, which demonstrates that the newly developed SPME water sampling device is suitable for long-term monitoring of organic pollutants in water.

Factors influencing enantiomeric fractions of hexabromocyclododecane measured using liquid chromatography/tandem mass spectrometry

Hexabromocyclododecane (HBCD), the most heavily produced of the cycloaliphatic brominated flame retardants (BFRs), is a mixture of three predominant diastereomers (alpha-, beta-, and gamma-HBCD), each with a corresponding pair of enantiomers. We have investigated the liquid chromatography/mass spectrometry (LC/MS) behaviour of the HBCD enantiomers, and demonstrated that enantiomeric fractions (EFs) calculated using data uncorrected for instrument and/or matrix effects can result in potentially inaccurate EF values. However, use of labelled surrogates effectively corrects for these effects. Experiments with racemic HBCD standards indicate that chromatographic factors, including mobile phase composition and column bleed from chiral stationary phases, may be contributors to variations in the mass spectrometric response of the HBCD enantiomers.

Polychlorinated biphenyls and hydroxylated polychlorinated biphenyls in plasma of bottlenose dolphins (Tursiops truncatus) from the Western Atlantic and the Gulf of Mexico

Polychlorinated biphenyls (PCBs) and hydroxylated metabolic products (OH-PCBs) were measured in plasma collected from live-captured and released bottlenose dolphins (Tursiops truncatus) from five different locations in the Western Atlantic and the Gulf of Mexico in 2003 and 2004. In 2004, the sum (sigma) of concentration of PCBs in plasma of dolphins sampled off Charleston, SC [geometric mean: 223 ng/g of wet weight (w.w.)] was significantly higher (p<0.05) than concentrations detected in animals from the Indian River Lagoon, FL (sigmaPCBs: 122 ng/g w.w.) and the Sarasota Bay, FL (sigmaPCBs: 111 ng/g w.w.). The PCB homolog profiles were similar among locations. Concentrations of OH-PCBs were significantly higher (p<0.05) in plasma of dolphins from Charleston, SC (sigmaOH-PCBs for 2003: 126 ng/g w.w.; 2004: 138 ng/g w.w.) than animals from Florida (sigmaOH-PCBs ranged from 6 to 47 ng/g w.w.) and Bermuda (8.3 ng/g w.w.); however, concentrations in the Charleston samples did not differ from animals captured in Delaware Bay, NJ (57 ng/g w.w.). The sigmaOH-PCBs constituted 2-68% of the total PCB concentrations in plasma. Dichloro- to nonachloro-OH-PCBs were quantified using high-resolution gas chromatography mass spectrometry, but only around 20% of OH-PCBs could be identified by comparison to authentic standards. Results from this study show that OH-PCB are important environmental contaminants in dolphins and suggest that PCBs, decades after their ban, may still constitute a threat to wildlife.

Empirical and modeling evidence of the long-range atmospheric transport of decabromodiphenyl ether

Understanding of the long-range atmospheric transport (LRT) behavior of decabromodiphenyl ether (BDE-209) is still limited. Most existing model-based approaches to assessing an organic chemical's potential for LRT have assumed invariant environmental conditions, even though many factors impacting on the atmospheric residence time are known to vary considerably over a variety of time scales. Model estimates of LRT also suffer from limited evaluation against observational evidence. Such evidence was sought from dated sediment cores taken from lakes along a latitudinal transect in North America. BDE-209 was generally detected only in recent sediment horizons, and sedimentation fluxes were found to decline exponentially with latitude. The empirical half-distance (EHD) for BDE-209 derived from surface flux data is approximately half that of the sigmaPCBs. A dynamic multimedia fate and transport model provides further insight into the temporal variability of processes that control LRT for BDE-209 and PCBs. The variability of precipitation, and in particular, the occurrence of time periods without precipitation coinciding with strong winds, influences the LRT potential of chemicals that combine a sufficiently long atmospheric half-life with very low volatility. Likewise, the forest filter effect may be important for a wider range of chemicals than believed previously, because models assuming constant precipitation fail to account for the impact of differences in dry deposition on days without rain. Chemicals that are both sorbed to particles and potentially persistent in the atmosphere, such as BDE-209, may have a larger potential for LRT than anticipated on the basis of earlier model evaluations. Still, the EHDs illustrate that the model seems to underestimate atmospheric loss processes of potential significance to BDE-209, illustrating the need to critically compare predictions of LRT against observations. Processes that need to be understood better in order to improve predictions of LRT for BDE-209 include particle dry deposition, precipitation scavenging, and photolysis in the sorbed state.

Bioaccumulation and trophic transfer of some brominated flame retardants in a Lake Winnipeg (Canada) food web

The extent of bioaccumulation and trophic transfer of brominated diphenyl ether (BDE) congeners, hexabromocyclododecane (HBCD) diastereoisomers (alpha, beta, and gamma), decabromodiphenylethane (DBDPE), and bis(2,4,6-tribromophenoxy)ethane (BTBPE) was examined in a Lake Winnipeg (Canada) food web. Six species of fish, zooplankton, mussels, sediment, and water from the south basin of the lake were selected for study. Significant positive correlations were found between concentrations of total (sigma) polybrominated diphenylethers (PBDEs; p < 0.005), sigmaHBCDs (p < 0.0001), BTBPE (p < 0.0001), and lipid content in fish. Strong positive linear relationships also were observed from individual plots of BDE 47, BDE 209, and DBDPE concentrations (lipid wt) and trophic level (based on delta15N), suggesting that these compounds biomagnify in the Lake Winnipeg food web. Biomagnification factors varied for the chemicals studied. Plots of log bioaccumulation factors for mussel and zooplankton versus log octanol-water partition coefficient (Kow) were similar and suggest that neither mussels nor zooplankton are in equilibrium with the water. Fifteen BDE congeners were consistently detected in water (dissolved phase, n = 3), with BDE 47 having the greatest concentration (17 pg/L). The rank order of compounds in water (arithmetic mean +/- standard error) were sigmaPBDEs (49 +/- 12 pg/ L) > alpha-HBCD (11 +/- 2 pg/L) > BTBPE (1.9 +/- 0.6 pg/L). Concentrations of DPDPE, BDE 209, and beta- and -gamma-HBCD isomers were below their respective method detection limits (MDLs) in water. Total PBDE concentrations in sediment (n = 4) were greater than any other brominated flame retardant examined in the present study and ranged from 1,160 to 1,610 ng/g (dry wt), with BDE 209 contributing roughly 50% of the total. The gamma-HBCD isomer was detected at concentrations of 50 +/- 20 pg/g (dry wt) in sediment, whereas BTBPE and DBDPE were consistently below their respective MDLs in sediment.

On-rod standardization technique for time-weighted average water sampling with a polydimethylsiloxane rod

In this study, a polydimethylsiloxane (PDMS) rod was developed as a passive sampler, based on the solid-phase microextraction (SPME) technique. The on-rod standardization technique was applied to the PDMS rod passive sampler. Using the desorption of the pre-loaded standard on the PDMS rod to calibrate the absorption of the target analytes allows for the determination of the time-weighted average (TWA) concentrations of pollutants in the aqueous media. The PDMS rod passive sampler with the on-rod standardization technique was tested in the laboratory with a flow-through system and was subsequently applied to measure TWA concentrations of polycyclic aromatic hydrocarbons (PAHs) in the field (Hamilton Harbour, Hamilton, Ont., Canada). Both the laboratory and field experiments demonstrated that, with the on-rod standardization technique, the PDMS rod can be successfully used as a passive sampler for TWA water sampling in the field. The PDMS rod passive sampler benefits from the inherent advantages of the SPME approach: it incorporates sampling, isolation and enrichment into one step. The design of this system also addressed the additional needs for passive sampling techniques, providing an economical approach to field sampling that is also easy to deploy. Rather, with this approach, TWA concentrations of target analytes can be obtained by one sampler, and can be analyzed directly, with no further sample preparation treatment required.

Dietary accumulation of hexabromocyclododecane diastereoisomers in juvenile rainbow trout (Oncorhynchus mykiss) I: bioaccumulation parameters and evidence of bioisomerization

Juvenile rainbow trout (Oncorhynchus mykiss) were exposed to three diastereoisomers (alpha, beta, gamma) of hexabromocyclododecane (C12H18Br6) via their diet for 56 d followed by 112 d of untreated food to examine bioaccumulation parameters and test the hypothesis of in vivo bioisomerization. Four groups of 70 fish were used in the study. Three groups were exposed to food fortified with known concentrations of an individual diastereoisomer, while a fourth group were fed unfortified food. Bioaccumulation of the gamma-diastereoisomer was linear during the uptake phase, while the alpha- and beta-diastereoisomers were found to increase exponentially with respective doubling times of 8.2 and 17.1 d. Both the beta- and the gamma-diastereoisomers followed a first-order depuration kinetics with calculated half-lives of 157 +/- 71 and 144 +/- 60 d (+/-1 x standard error), respectively. The biomagnification factor (BMF) for the alpha-diastereoisomer (BMF = 9.2) was two times greater than the beta-diastereoisomer (BMF = 4.3); the large BMF for the beta-diastereoisomer is consistent with this diastereoisomer dominating higher-trophic-level organisms. Although the BMF of the beta-diastereoisomer suggests that it will biomagnify, it is rarely detected in environmental samples because it is present in small quantities in commercial mixtures. Results from these studies also provide evidence of bioisomerization of the beta- and gamma-diastereoisomers. Most importantly, the alpha-diastereoisomer that was recalcitrant to bioisomerization by juvenile rainbow trout in this study and known to be the dominant diastereosiomer in fish was bioformed from both the beta- and the gamma-diastereoisomers. To our knowledge, this is the first report of bioisomerization of a halogenated organic pollutant in biota.

Field Sampling with a Polydimethylsiloxane Thin-Film

In this research, field samplers are developed using polydimethylsiloxane (PDMS) thin-film as the extraction phase. This technique is based on a similar theory, the solid-phase microextraction (SPME) technique. More specifically, the development of the field sampler involves cutting a section of PDMS thin-film into a specific size and shape, and mounting it onto a stainless steel wire (the handle). The thin-film is then placed into a protective copper cage prior to deployment to prevent biofouling. Kinetic calibration or equilibrium calibration with the standards in the extraction phase is used to introduce an isotopically labeled internal standard for on-site calibration. The initial loading of the standard onto the thin-film and the amount of standard remaining on the thin-film are determined using gas chromatography-mass spectrometry and subsequently used to estimate the concentration of the target analytes. In addition, the field samplers are deployed in the field at two locations (the Meuse River in Eijsden, The Netherlands from April to May, 2005 and Hamilton Harbour located at the western tip of Lake Ontario, ON, Canada from September to December, 2006). Polycyclic aromatic hydrocarbons are identified, and concentrations of fluoranthene and pyrene are estimated in the low ng/L range. The results from both sampling sites are within the expected ranges for environmental samples. This polymeric extraction phase has a high surface-to-volume ratio compared with SPME, which results in higher sensitivity and mass uptake, leading to the detection of lower levels of analytes that many other techniques are unable to achieve.

Levels and trends of brominated flame retardants in the Arctic

Polybrominated diphenyl ethers (PBDEs) containing two to seven bromines are ubiquitous in Arctic biotic and abiotic samples (from zooplankton to polar bears (Ursus maritimus) and humans; air, soil, sediments). The fully brominated decabromodiphenyl ether (BDE-209), hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBPA) and polybrominated biphenyls (PBBs) are also present in biotic and abiotic samples. Spatial trends of PBDEs and HBCD in top predators are similar to those seen for polychlorinated biphenyls (PCBs) and indicate western Europe and eastern North America as source regions. Concentrations of tetra- to heptaBDEs have increased significantly in North American and Greenlandic Arctic biota and in Greenland freshwater sediments paralleling trends seen further south. For BDE-209, increasing concentrations in Greenlandic peregrine falcons (Falco peregrinus) and in dated lake sediment cores in the Canadian Arctic have been seen during the 1990s. BDE-47, -99, -100 and -153 are observed to biomagnify in Arctic food webs. summation operatorPBDE concentrations in Arctic samples are lower than in similar sample types from more southerly regions and are one or more orders of magnitude lower than summation operatorPCB concentrations except for some levels for air. Air and harbor sediment results for PBDEs indicate that there are local sources near highly populated areas within the Arctic. Findings of PBBs on moss and TBBPA on an air filter, and that both are found in biota at high trophic levels indicates that these compounds may also reach the Arctic by long-range atmospheric transport. Based on the evidence of their presence in the Arctic and indications that most if not all are undergoing long-range transport, these brominated flame retardants (BFRs) have characteristics that qualify them as POPs according to the Stockholm Convention.

Distribution of hexabromocyclododecane in Detroit River suspended sediments

The distribution of hexabromocyclododecane (HBCD) isomers (alpha, beta and gamma) was determined in Detroit River suspended sediments using liquid chromatography tandem mass spectrometry (LC/MS/MS). Individual isomers of HBCD were measured at concentrations ranging from <0.025 to 1.9 ng/g (dry wt.) for the alpha-isomer, <0.025 to 0.28 ng/g for the beta-isomer, and <0.025 to 2.3 ng/g for the gamma-isomer. Concentrations of total HBCD ranged from <0.075 to 3.7 ng/g. Roughly two-thirds of HBCD profiles in suspended sediments were dominated by the gamma-isomer, and were similar to profiles of commercial technical mixtures. Profiles in the remaining samples were dominated by the alpha-isomer. The beta-isomer was consistently detected at substantially lower levels than the other isomers; this isomer is a minor constituent in the commercial technical mixtures. Seasonal sampling showed significant shifts in the relative ratios of the HBCD isomers. The spatial distribution of HBCD in the Detroit River was similar to other persistent organic pollutants (e.g., PCBs), and showed a strong association with urban/industrial activities in the watershed. However, the highest HBCD concentrations (2.6-3.7 ng/g) were associated with areas of contemporary industrial activity, and were much lower than maximum concentrations of PCBs (2.2 microg/g) found in areas of the Detroit River associated with historical industrial activity.

Inhibition of metamorphosis in tadpoles of Xenopus laevis exposed to polybrominated diphenyl ethers (PBDEs)

Tadpoles of the African clawed frog, Xenopus laevis were exposed, beginning at stage 50, to a commercial pentabromodiphenyl ether mixture (DE-71) through the diet. Subsequent experiments were conducted using a single intraperitoneal injection at stage 58 with limited quantities of two purified brominated diphenyl ether (BDE) congeners, BDE47 and BDE99 and DE-71 to determine the relative potency of these BDE congeners within the commercial mixture. Significant inhibition of tail resorption, delayed metamorphosis and impacts on skin pigmentation were observed in Xenopus exposed to DE-71 in the diet at nominal doses of 1000 and 5000 microgg(-1) of food. The estimated time required for 50% of the tadpoles to complete metamorphosis was significantly lengthened in Xenopus exposed to a dietary concentration of 1 microg DE-71 per gram of food. Analysis of PBDEs (sum of 32 congeners) in Xenopus from the treatment with 5000 microgg(-1) of DE-71 indicated that the frogs accumulated an average of 1030 microgg(-1) (wet weight) of PBDEs. In the intraperitoneal injection trials, similar inhibitory responses were observed in Xenopus injected with DE-71 at a nominal dose of 60 microg per tadpole, or injected with BDE47 at a nominal dose of 100 microg per tadpole. No responses were observed in Xenopus injected with BDE99 at doses up to 100 microg per tadpole. Complete inhibition of metamorphosis was observed only in the highest DE-71 dietary treatment. The results of this study are consistent with a mechanism of action of PBDEs involving competitive inhibition of binding of thyroid hormones to transporter proteins, although the mechanism cannot be definitively determined from this study. The observed effects may have occurred through other mechanisms, including sublethal toxicity. The doses used in this study are greater than the levels of PBDEs to which anurans are exposed in the environment, so further studies are required to determine whether exposure to PBDEs at environmentally relevant concentrations can affect frog metamorphosis.

Northern Rivers Ecosystem Initiative: distribution and effects of contaminants

In response to a number of recommendations following the Northern Rivers Basin Studies (NRBS) contaminant program, the Northern Rivers Ecosystem Initiative (NREI) focused considerable attention on assessing contaminants from specific sources including pulp mill effluents, atmospheric transport of mercury and the Alberta oil sands operations. NRBS identified a number of major contaminants of concern including polychlorinated biphenyls, dioxins and furans, mercury and various hydrocarbons. Together, the NRBS and the NREI studies have demonstrated major declines in the levels of dioxins and furans over the last decade as pulp and paper mills have changed their process and treatment strategies in response to new Federal regulations. Polychlorinated biphenyls however, continue to be a concern for the region as their levels have not declined in fish and sediments over the course of these studies. Higher levels in sediments downstream of Grande Prairie and Hinton were identified, but the source of these contaminants remains unknown. Chlorinated pesticides were also investigated, and although toxaphene, DDT and other chlorinated organic pesticides were detected in fish tissue, they were present at very low levels. Studies on the oil sands industry in northern Alberta demonstrated limited impacts on the Athabasca River to date, although studies did identify slight to moderate impacts of natural oil seeps on fish and benthic communities in tributary streams. NREI studies also identified endocrine active compounds in the three pulp and paper mill effluents tested, but endocrine disruptive effects in wild fish were minimal. Municipal sewage effluents also contain endocrine active compounds and it is recommended that monitoring continue around these point sources.

Polybrominated diphenyl ethers and hydroxylated and methoxylated brominated and chlorinated analogues in the plasma of fish from the Detroit River

Novel classes and congeners of contaminant residues that are structurally analogous to polybrominated diphenyl ether (PBDE) flame retardants were assessed in the plasma of seven benthic- and six pelagic-feeding fish species from the highly contaminated Detroit River corridor, namely, hydroxylated-PBDEs (OH-PBDEs), methoxylated-PBDEs (MeO-PBDEs), and the antimicrobial OH-trichlorodiphenyl ether, triclosan, and its methylated (MeO) triclosan analogue. In all samples sigmaPBDE concentrations were comprised mainly of BDE47, BDE99, and BDE100 (>85%) and ranged from 155 pg/g wet weight (ww) to 21 069 pg/g ww. Of the 14 OH-PBDE congeners assessed, as many as 10 congeners were identified, although profiles were generally dominated by 6-OH-BDE47 with lesser amounts of 2'-OH-BDE68, 4'-OH-BDE49, and 4-OH-BDE42. sigmaOH-PBDE concentrations ranged from 2.7 to 198 pg/g ww, with sigmaPBDE to sigmaOH-PBDE concentration ratios ranging from 0.0005 to 0.02. OH-PBDEs are likely derived in these freshwater species as metabolites of precursor PBDEs and are subsequently retained in the blood, for example, 6-OH-BDE47, 4'-OH-BDE49, and 4-OH-BDE42 could be derived from BDE47. Portions of concentrations of the OH-PBDEs may also be of alternate origins and are accumulated and retained in these fish. In all samples, the 14 MeO-PBDEs monitored were below detection (<0.01 pg/g ww). Anthropogenic triclosan concentrations ranged from 750 to >10 000 pg/g ww and is clearly a bioaccumulative halogenated phenolic compound in these fish. MeO-triclosan concentrations were considerably lower. In addition to emerging classes of brominated contaminant such as PBDEs, whether of metabolic or anthropogenic origin, fish collected from the Detroit River are exposed to a complex profile of PBDE-like organohalogens.

Fate of organochlorine contaminants in arctic and subarctic lakes estimated by mass balance modelling

Elevated concentrations of some persistent organic pollutants (POPs) in fish from arctic and subarctic lakes have been hypothesized to be due to processes within food webs and fish physiology. We investigated limnological processes and contaminant chemistry as explanations of these elevated concentrations by developing and applying fugacity-based mass balance models to a relatively small lake in the high arctic and a series of larger lakes in the southern Yukon River basin. The results indicate that high arctic lakes are transient and inefficient sinks for POPs. The mobility of POPs in high arctic lakes is conferred by their hydrologic regime (i.e. partial through flow of melt water loadings) and minimal scavenging and retention in sediments due to extremely low organic carbon in settling and sediment particles. Contaminant dynamics in lakes of the south Yukon River basin are governed by hydrology (i.e., water residence time), because, similarly to high arctic lakes, most of the contaminant inventory resides in the water column due to inefficient scavenging by settling particles. For the less persistent compounds, long water residence time shifts the major loss process from export to degradation. Model results also suggest relatively short degradative half-lives of the hexachlorocyclohexanes (sum of HCHs) and endosulfan, particularly in high arctic Amituk Lake.

Refinements to the diastereoisomer-specific method for the analysis of hexabromocyclododecane

The emergence of hexabromocyclododecane (HBCD) as a bromine-based flame retardant of concern is partly attributable to recent measurements on the environmental occurrence of the individual diastereoisomers (alpha, beta and gamma). These measurements were fuelled by a newly developed liquid chromatography/tandem mass spectrometric (LC/MS/MS)-based analytical method. However, in the course of our recent studies on the environmental fate and behaviour of the diastereoisomers of HBCD, some interesting features of the LC/MS/MS method became apparent. For example, the ion signal of the native ions was found to be dependent on the final extract volume. This was true for both biotic and sediment samples and was found to arise from the suppression of the ion signal due to endogenous material in the extracts that escape clean-up. We have also found differences in the stability of the diastereoisomers in different solvents. If left unaccounted for, both factors can compromise analytical measurement data. By way of a series of controlled experiments conducted at our two laboratories [Department of Fisheries & Oceans Canada (DFO) and Environment Canada (EC)], we illustrate these features and demonstrate that use of newly synthesized labelled HBCD isomers [(13-carbon (13C) and deuterium (d18)] can minimize and often circumvent matrix-related effects.

Biomagnification of alpha- and gamma-hexabromocyclododecane isomers in a Lake Ontario food web

The extent of bioaccumulation of hexabromocyclododecane (HBCD) isomers (alpha, beta, and gamma) was determined in the Lake Ontario pelagic food web using liquid chromatography tandem mass spectrometry (LC/MS/MS). Concentrations of the alpha-isomer were consistently higher than that of the gamma-isomer. The beta-isomer was below method detection limits in all samples. Whole body concentrations (ng/g, wet wt) of alpha- and gamma-HBCD were highest in the top predator lake trout samples ranging from 0.4 to 3.8 ng/g for the alpha-isomer and 0.1 to 0.8 ng/g for the gamma-isomer. For the prey fish species, the trends in alpha- and gamma-HBCD levels were slimy sculpin > smelt > alewife. Mean concentrations of total (sigma) HBCD (sum of alpha- and gamma-isomers) in the macrozooplankter Mysis relicta (0.14 +/- 0.02 ng/g wet wt) and in the benthic invertebrate Diporeia hoyi (0.16 +/- 0.02 ng/g, wet wt) were similar and approximately twice as high as in plankton (0.06 +/- 0.02 ng/g, wet wt). A strong positive linear relationship was found between sigmaHBCD concentrations (wet wt) and trophic level based on delta15N suggesting that HBCD biomagnifies in the Lake Ontario food web. The trophic magnification factor (TMF = 6.3) derived from the slope of the sigmaHBCD - trophic level relationship was slightly higher than TMFs for p,p'-DDE (6.1) and sigmaPCBs (5.7) found previously. Biomagnification factors (BMF, calculated as the ratio of lipid corrected concentration in predator/lipid corrected concentration in prey) were variable between feeding relationships and ranged from 0.4 to 10.8 for the alpha-isomer and from 0.2 to 10 for gamma-isomers.

Method for the determination of organophosphate insecticides in water, sediment and biota

A procedure for the determination of 13 organophosphate insecticides (OPs) in water, sediment and biota at low ppb levels is described. Samples were extracted with dichloromethane or acetone/hexane and cleaned up with micro-column silica gel chromatography. Measurements were made by dual capillary column gas chromatography using both nitrogen-phosphorus (NPD) and electron capture (ECD) detection. Recoveries from fortified water samples ranged from 76% to 102% for all sample types. Practical detection limits ranged between 0.003 and 0.029 microg/l in natural water samples, 0.0004-0.005 microg/g w.w. for sediments, and 0.001-0.005 microg/g w.w for biota using the NPD and ECD method. Losses in sediments were experienced when sulphur was removed. Precision and accuracy were not affected in sediment samples where sulphur was not removed.

Debromination of the flame retardant decabromodiphenyl ether by juvenile carp (Cyprinus carpio) following dietary exposure

The congener 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE 209) is the primary component in a commonly used flame retardant known as decaBDE. This flame retardant constitutes approximately 80% of the world market demand for polybrominated diphenyl ethers (PBDEs). Because this compound is very hydrophobic (log K(ow) approximately 10), it has been suggested that BDE 209 has very low bioavailability, although debromination to more bioavailable metabolites has also been suggested to occur in fish tissues. In the present study, juvenile carp were exposed to BDE 209 amended food on a daily basis for 60 days, followed by a 40-day depuration period in which the fate of BDE 209 was monitored in whole fish and liver tissues separately. No net accumulation of BDE 209 was observed throughout the experiment despite an exposure concentration of 940 ng/day/fish. However, seven apparent debrominated products of BDE 209 accumulated in whole fish and liver tissues over the exposure period. These debrominated metabolites of BDE 209 were identified as penta- to octaBDEs using both GC/ECNI-MS and GC/HRMS. Using estimation methods for relative retention times of phenyl substitution patterns, we have identified possible structures for the hexa- and heptabromodiphenyl ethers identified in the carp tissues. Although exposure of carp to BDE 209 did not result in the accumulation of BDE 209 in carp tissues, our results indicate evidence of limited BDE 209 bioavailability from food in the form of lower brominated metabolites.

Recommendations for monitoring of polybrominated diphenyl ethers in the Canadian environment

Polybrominated diphenyl ethers (PBDEs) have been reported in air, surface waters, suspended sediments, soil, sediment, fish, marine mammals, and bird eggs throughout Canada, from the St. Lawrence Estuary to the Strait of Georgia and the northernmost reaches of the Canadian Arctic. Canadian scientists have detected the presence of PBDEs in breast milk in every Canadian province. In fact, recent data on temporal trends strongly suggests that the concentrations of PBDEs are on the rise in the Canadian environment. These findings are similar to those reported in other nordic countries, and have prompted several countries to implement environmental monitoring programs. Among the key challenges currently facing Canada and other countries concerns how best to measure these chemicals in different matrices. In this paper, several analytical methods cited in the scientific literature for determining PBDE concentrations in different abiotic and biological matrices are reviewed. The critical criteria required for accurate determination of PBDEs in complex environmental matrices are discussed, including instrument sensitivity, reliability, potential interference's and the need for specialized instrumentation for the determination of compounds up to 975 Daltons. While a single analytical method that meets these and other criteria has not yet been perfected by scientists, GC/HRMS-based methods amenable to isotope dilution techniques warrant further refinement, and likely represent the best tools for future environmental monitoring programs.

Polybrominated diphenyl ether flame retardants in the North American environment

North America consumes over half of the world's production of polybrominated diphenyl ether (PBDE) flame retardants. About 98% of global demand for the Penta-BDE mixture, the constituents of which are the most bioaccumulative and environmentally widespread, resides here. However, research on the environmental distribution of PBDEs in North America has lagged behind that in Northern Europe. Examination of available governmentally maintained release data suggests that Deca-BDE use in the US substantially exceeds that in Canada. Penta-BDE use probably follows a similar pattern. PBDE demand in Mexico is uncertain, but is assumed to be comparatively modest. Recent research examining air, water, sediment, sewage sludge and aquatic biota suggests that Penta-BDE constituents are present in geographically disparate locations in the US and Canada. The less brominated congeners have been observed in areas distant from their known use or production, e.g. the Arctic. PBDEs have been detected in low concentrations in North American air, water and sediment, but much higher levels in aquatic biota. Increased burdens as a function of position in the food web have been noted. PBDE concentrations in US and Canadian sewage sludges appear to be at least 10-fold greater than European levels and may be a useful barometer of release. In general, PBDE concentrations in environmental media reported in North America are comparable or exceed those observed elsewhere in the world. In contrast to Europe, environmental burdens are increasing over time here, consistent with the greater consumption of the commercial mixtures. However, data remain relatively scarce. Deca-BDE in the North American environment appears largely restricted to points of release, e.g. urban areas and those where PBDE-containing sewage sludges have been applied. This lack of redistribution is likely due to its extremely low volatility and water solubility. Penta-BDE and Deca-BDE products are used in different applications and this may also be a factor controlling their environmental release.

Levels and trends of polybrominated diphenylethers and other brominated flame retardants in wildlife

In this paper, we review the available data for polybrominated diphenylethers (PBDEs) and other flame retardants in wildlife, with the exception of fishes from Europe and North America which are covered in more detail elsewhere. More data are available for PBDEs than for other compounds, and these show that some of these compounds have become widely distributed in the environment, being found in samples from Europe, Australia, Azerbaijan, North America and the Arctic. Most available data relate to birds and their eggs and marine mammals, but the results of two food web studies are also included. The detection of PBDEs in pelagic marine mammals which feed in deep offshore waters, including baleen whales, indicate that these compounds have found their way into deep-water, oceanic food webs as well as the coastal/shallow sea examples described in detail. In the North Sea study, the most marked increase in lipid-normalised concentrations of six BDE congeners occurred during transfer from predatory fish to marine mammals. In the St. Lawrence Estuary study, marked differences in the ratios observed between species suggested that some fish species may be able to metabolise BDE99.A number of time trend studies have also been conducted, notably in guillemot eggs from Sweden (1969-2000), beluga whales from the Canadian Arctic (1982-1997 and 1989-2001) and from the St. Lawrence Estuary (1988-1999), and ringed seals from the Canadian Arctic (1981-2000). In the temperate latitudes, from these and other studies (e.g. in dated sediment cores), PBDE concentrations began to rise earlier than in those from high latitudes, in line with data for production and use. These trends have now slowed in many cases. Declines could be expected in Europe for many congeners following the cessation of manufacture and use of the penta-mix formulation in the EU, though these are not yet apparent in environmental samples. In Arctic biota, however, the rapidly rising concentrations seen currently in Canada could be expected to continue for some time, reflecting continued production and use of the penta-mix formulation in North America (>95% of the world total) and the impact of long-range atmospheric transport.

An overview of commercially used brominated flame retardants, their applications, their use patterns in different countries/regions and possible modes of release

Brominated flame retardants (BFRs) are used in a variety of consumer products and several of those are produced in large quantities. These compounds have been detected in environmental samples, which can be attributed to the anthropogenic uses of these compounds. Brominated flame retardants are produced via direct bromination of organic molecules or via addition of bromine to alkenes; hence, an overview of the production and usage of bromine over the past three decades is covered. Production, application, and environmental occurrence of high production brominated flame retardants including Tetrabromobisphenol A, polybrominated biphenyls, Penta-, Octa-, Deca-brominated diphenyl ether (oxide) formulation and hexabromocyclododecane are discussed.

Airborne haloacetic acids

Haloacetic acid (HAA) concentrations were measured in air samples from a semi-rural and a highly urbanized site in southern Ontario throughout 2000 to investigate their sources and gas-particle partitioning behavior. Denuders were efficient for collection of gaseous HAAs, and the particle phase was collected on a downstream quartz filter with negligible breakthrough. Total HAA concentrations (i.e., gas + particles) ranged between <0.025 and 19 ng m(-3) for individual HAAs at both sites. The dominant airborne HAA was monochloroacetic acid (MCA), followed in decreasing order by dichloroacetic acid (DCA), trifluoroacetic acid (TFA), and trichloroacetic acid (TCA). Difluoroacetic acid (DFA), monofluoroacetic acid (MFA), and chlorodifluoroacetic acid (CDFA) were also frequently detected at lower concentrations. Between sites, TFA, DFA, MFA, and TCA concentrations were significantly higher in Toronto, while CDFA concentrations were higher in Guelph. HAAs were primarily in the gas phase all year; however, during colder months, particle-phase HAA concentrations increased relative to the gas phase. Trichloroacetic acid had the highest particle fraction (phi) for all detected HAAs, with a mean phi of 0.51 and 0.56 for Guelph and Toronto, respectively, and both vapor pressure and acid strength appeared to influence gas-particle partitioning. Temporal trends at both sites were partially explained by temperature, short-wave radiation, and particle mass (PM10), leading to indications of the respective sources. A simple deposition model indicated that dry deposition of TFA and TCA should not be neglected in temperate mid-latitude environments and that precipitation concentrations can be successfully predicted by the Henry's law constant.

Persistent organic pollutants in Detroit River suspended sediments: polychlorinated dibenzo-p-dioxins and dibenzofurans, dioxin-like polychlorinated biphenyls and polychlorinated naphthalenes

Suspended sediments from the Detroit River were collected in 1999 and 2000 using sediment traps at sites ranging from western Lake Erie to southern Lake St. Clair and analyzed to determine the spatial distributions of contaminants including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs), dioxin-like PCBs (DLPCBs) and polychlorinated naphthalenes (PCNs). Concentrations of all three contaminant classes were clearly elevated at sites in the lower reaches of the river in the Trenton Channel. The potential influence of the Trenton Channel as a source of contamination to western Lake Erie was further evidenced by PCDD/PCDF homologue profiles, which indicated a contribution from chemical manufacturing in addition to the normal background combustion profile. Toxic equivalents (TEQs) for PCDDs/PCDFs generally exceeded those for DLPCBs; combined total TEQs in July 2000 for these two compound classes ranged from 2.30 pg/g in southern Lake St. Clair to 306 pg/g at a station just downstream of the outflow of Monguagon Creek in the Trenton Channel. The spatial distribution of PCN contamination was similar to that of PCDDs/PCDFs and DLPCBs, with the highest level of total PCNs (8200 ng/g) detected at a site in the Trenton Channel near Elizabeth Park; TEQs for PCNs in the Trenton Channel ranged from 73 to 3300 pg/g. The data indicate that PCNs represent a significant contribution to dioxin-like biological activity in Detroit River suspended sediments.

Spatial distribution of polybrominated diphenyl ethers and polybrominated biphenyls in lake trout from the Laurentian Great Lakes

Concentrations of two types of brominated flame-retardants (BFRs); polybrominated diphenyl ethers (PBDEs) and polybrominated biphenyls (PBBs) were determined in a single age class of lake trout (Salvelinus namaycush) collected from the Laurentian Great Lakes in 1997. Mean concentrations of total PBDE were highest in samples from Lake Ontario at 95+/-22 ng/g wet weight (ww) or 434+/-100 ng/g lipid weight (lw) while the lowest concentrations were observed in Lake Erie lake trout (27+/-8.6 ng/g ww, 117+/-37 ng/g lw). In all samples, the predominant PBDE congeners were 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), 2,2',4,4',5-pentabromodiphenyl ether (BDE-99), and 2,2',4,4', 6-pentabromodiphenyl ether (BDE-100), which are the primary components of the commonly used penta-BDE formulation flame retardant. Lake trout collected from Lake Huron had the highest concentrations of PBBs (3.1+/-1.7 ng/g ww, 15+/-8.5 ng/g lw), while the lowest levels were detected in fish from Lake Superior (0.25+/-0.13 ng/g ww, 1.7+/-0.89 ng/g lw). In all lake trout samples, 2,2',4,4',5,5'-hexabromobiphenyl (BB-153), a major constituent of the flame-retardant FireMaster BP-6, was the predominant PBB congener.

Assessing the environmental fate of chemicals of emerging concern: a case study of the polybrominated diphenyl ethers

It is suggested that assessments of chemicals of emerging concern can be rationally structured around a multistage process in which fate and risk are evaluated with increasing accuracy as new data become available. An initial tentative and approximate assessment of fate and risk can identify key data gaps and justify and direct further investigations, which progressively improve the reliability of the assessment. This approach is demonstrated for a class of chemicals, the polybrominated diphenyl ethers (PBDEs), which is of increasing concern, but about which there is presently a lack of comprehensive data on properties, sources, fate and effects. Specifically, 20 PBDE congeners are investigated using the suggested approach and research needs are identified.

Factors affecting the occurrence and enantiomeric degradation of hexachlorocyclohexane isomers in northern and temperate aquatic systems

Concentrations of (alpha- and gamma-hexachlorocyclohexane (HCH), alpha/gamma-HCH ratios, and enantiomer ratios (ER) of alpha-HCH were measured in lakes in the arctic, subarctic, Great Lakes, Canada, and temperate regions, and temperate and arctic wetlands and streams. The highest concentrations of alpha-HCH were found in cold, large, and oligotrophic lakes such as those in the arctic, subarctic, and the upper Great Lakes, which is attributed to greater inputs from atmospheric deposition and slower loss rates relative to warmer, temperate lakes. High alpha/gamma-HCH ratios in northern systems indicate aged HCH that has undergone long-range transport to high latitude areas, whereas low ratios in the lower Great Lakes and small temperate systems indicate recent gamma-HCH usage and residual alpha-HCH concentrations. Enantioselective degradation (ERs ranged from 0.31 to 0.7) was greatest in small, high arctic lakes and streams and in large lakes in the subarctic in which alpha-HCH concentrations and contact time between chemical and sediments are highest and nutrient concentrations are lowest. Low ERs were found in wetlands and streams in which contact between chemical and sediments was greatest. Conversely, minimal enantioselective degradation occurred in temperate small lakes and wetlands (ERs ranging from 0.77 to 1.06), despite the warmer temperatures, greater microbial populations, and nutrient availability. The results suggest that enantioselective degradation is optimized by maximal contact between chemical and sediment substrates in nutrient-poor waters in which, it is hypothesized, oligotrophic bacteria may act as biofilms.

A gas chromatography/high-resolution mass spectrometry (GC/HRMS) method for determination of polybrominated diphenyl ethers in fish

A method for the determination of polybrominated diphenyl ethers (PBDEs) in biota for routine analysis is described. The mass spectroscopic (MS) evaluation of 23 brominated diphenyl ethers, under electron ionization and electron capture negative ion conditions using magnetic sector and quadrupole mass spectrometers, showed that high-resolution mass spectrometry (HRMS) under electron ionization conditions was the most reliable technique, with high selectivity and adequate sensitivity. The instrument detection limit for this method ranged for individual congeners between 4.8 and 0.1 pg for 3-bromodiphenyl ether (BDE-2) and 2,3',4,4'-tetrabromodiphenyl ether (BDE-66), respectively, and method detection limit for each homologue group ranged between 5 pg/g for salmon certified reference material (CRM) and 93 pg/g for lake trout CRM. The effectiveness of this method was evaluated by analyzing the occurrence of PBDEs in commercially available CRMs comprising Lake Ontario lake trout, Pacific herring, and sockeye salmon. The average coefficients of variation for the replicate analyses of PDBEs in several tissue samples were: 25% for lake trout, 36% for Pacific herring, and 34% for sockeye salmon. The average deviations in the inter-laboratory study were: 14% for lake trout, 15% for Pacific herring, and 37% for sockeye salmon. Results indicated that the described method, based on gas chromatography/high-resolution mass spectrometry, is reliable for determining PBDE concentrations in biological tissues.

Contaminants in the Canadian Arctic: 5 years of progress in understanding sources, occurrence and pathways

Recent studies of contaminants under the Canadian Northern Contaminants Program (NCP) have substantially enhanced our understanding of the pathways by which contaminants enter Canada's Arctic and move through terrestrial and marine ecosystems there. Building on a previous review (Barrie et al., Arctic contaminants: sources, occurrence and pathways. Sci Total Environ 1992:1-74), we highlight new knowledge developed under the NCP on the sources, occurrence and pathways of contaminants (organochlorines, Hg, Pb and Cd, PAHs, artificial radionuclides). Starting from the global scale, we examine emission histories and sources for selected contaminants focussing especially on the organochlorines. Physical and chemical properties, transport processes in the environment (e.g. winds, currents, partitioning), and models are then used to identify, understand and illustrate the connection between the contaminant sources in industrial and agricultural regions to the south and the eventual arrival of contaminants in remote regions of the Arctic. Within the Arctic, we examine how contaminants impinge on marine and terrestrial pathways and how they are subsequently either removed to sinks or remain where they can enter the biosphere. As a way to focus this synthesis on key concerns of northern residents, a number of special topics are examined including: a mass balance for HCH and toxaphene (CHBs) in the Arctic Ocean; a comparison of PCB sources within Canada's Arctic (Dew Line Sites) with PCBs imported through long-range transport; an evaluation of concerns posed by three priority metals--Hg, Pb and Cd; an evaluation of the risks from artificial radionuclides in the ocean; a review of what is known about new-generation pesticides that are replacing the organochlorines; and a comparison of natural vs. anthropogenic sources of PAH in the Arctic. The research and syntheses provide compelling evidence for close connectivity between the global emission of contaminants from industrial and agricultural activities and the Arctic. For semi-volatile compounds that partition strongly into cold water (e.g. HCH) we have seen an inevitable loading of Arctic aquatic reservoirs. Drastic HCH emission reductions have been rapidly followed by reduced atmospheric burdens with the result that the major reservoir and transport agent has become the ocean. In the Arctic, it will take decades for the upper ocean to clear itself of HCH. For compounds that partition strongly onto particles, and for which the soil reservoir is most important (e.g. PCBs), we have seen a delay in their arrival in the Arctic and some fractionation toward more volatile compounds (e.g. lower-chlorinated PCBs). Despite banning the production of PCB in the 1970s, and despite decreases of PCBs in environmental compartments in temperate regions, the Arctic presently shows little evidence of reduced PCB loadings. We anticipate a delay in PCB reductions in the Arctic and environmental lifetimes measured in decades. Although artificial radionuclides have caused great concern due to their direct disposal on Russian Shelves, they are found to pose little threat to Canadian waters and, indeed, much of the radionuclide inventory can be explained as remnant global fallout, which was sharply curtailed in the 1960s, and waste emissions released under license by the European reprocessing plants. Although Cd poses a human dietary concern both for terrestrial and marine mammals, we find little evidence that Cd in marine systems has been impacted by human activities. There is evidence of contaminant Pb in the Arctic, but loadings appear presently to be decreasing due to source controls (e.g. removal of Pb from gasoline) in Europe and North America. Of the metals, Hg provokes the greatest concern; loadings appear to be increasing in the Arctic due to global human activities, but such loadings are not evenly distributed nor are the pathways by which they enter and move within the Arctic well understood.