Dechlorane Plus and Related Compounds in the ... - ACS Publications

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Dechlorane Plus and Related Compounds in the Environment: A Review Ed Sverko,† Gregg T. Tomy,‡ Eric J. Reiner,§ Yi-Fan Li,||,^ Brian E. McCarry,# Jon A. Arnot,3 Robin J. Law,O and Ronald A. Hites[,* †

Science and Technology Branch, Environment Canada, Burlington, ON, L7R 4A6, Canada Fisheries and Oceans, Canada, Arctic Aquatic Research Division, Winnipeg, MB, R3T 2N6, Canada § Ontario Ministry of the Environment, Toronto, ON, M9P 3V6, Canada Science and Technology Branch, Environment Canada, Toronto, ON, M3H 5T4, Canada ^ International Joint Research Center, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, China # Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON, L8S 4M1, Canada 3 Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, M1C 1A4, Canada O Cefas Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk NR33 0HT, United Kingdom [ School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana 47405, United States

)

‡

bS Supporting Information ABSTRACT: Dechlorane Plus (DP) is a high production volume, chlorinated flame retardant. Despite its long production history, it was only recently found in the environment. The first “sightings” of DP were in the North American Great Lakes, but subsequent work has indicated that DP is a global contaminant. For example, DP has recently been detected along a pole-to-pole transect of the Atlantic Ocean. Although it was initially thought that DP was produced only in North America, another DP production plant has recently been identified in China. During the course of characterizing DP in the environment, other “DP-like” compounds were identified. These DP analogs, some created from impurities contained in the starting materials during DP’s synthesis, have also been detected globally. Screening-level modeling data are in general agreement with available environmental measurements, suggesting that DP and it analogs may be persistent, bioaccumulative, and subject to long-range transport and that these chemicals may be candidates for Annex D evaluation under the United Nations Stockholm Convention on Persistent Organic Pollutants. However, more research is required to better quantify the emissions, exposures, and toxicological effects of DP and its analogs in the environment. In particular, there is a need to obtain more monitoring, bioaccumulation, degradation rate, and toxicity information.

’ INTRODUCTION In 2006, Hoh et al. first reported on the environmental occurrence of Dechlorane Plus (DP) within the North American Great Lakes Basin, where it is manufactured by OxyChem in Niagara Falls, New York.1 This recent discovery was surprising, considering that this chlorinated flame retardant had been produced for at least 40 years. DP is produced by the Diels
Alder condensation of hexachlorocyclopentadiene and 1,5cyclooctadiene in a 2:1 molar ratio. The resulting material consists of the syn and anti isomers. These isomers are present in the technical product in a ratio of about 1:3; that is, the anti isomer is about 75% of the total. DP is used as a flame retardant in electrical hard plastic connectors in televisions and computer monitors, wire coatings, and furniture.2 DP is currently classified as a low production volume chemical in the EU, but it has been identified by the U.S. Environmental Protection Agency as a high production volume chemical, r 2011 American Chemical Society

meaning that DP is produced or imported into the U.S. in quantities of at least 450 000 kg per year. Received: January 25, 2011 Accepted: April 29, 2011 Revised: April 15, 2011 Published: May 17, 2011 5088

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Environmental Science & Technology After the Hoh et al. paper,1 other researchers measured DP in gull eggs and house dust,3
5 and sporadic evidence showing its occurrence in other regions of the world (i.e., Spain, Korea, and China) has led to the prospect that DP is a worldwide contaminant.6 More strikingly, M€oller et al. recently detected DP in air sampled along an oceanic transect from Greenland to Antarctica; these data indicate that DP is a global pollutant, susceptible to long-range atmospheric transport.7 Additionally, Wang et al. identified another DP production facility in China.8 More recently, several “DP-like” substances (Dechlorane-602, Dechlorane-603, and Dechlorane-604) have also been detected in the Great Lakes.9,10 Unlike DP, information on the production volumes and applications of these compounds is not available. DP has been identified by the European Commission as a possible replacement for the now restricted decabromodiphenyl ether flame retardant.11 Therefore, it behooves scientists to measure current levels of DP and its analogs in the environment and to determine what effect an increase in production and/or use would have on environmental and human health. In this review, we summarize the current state of knowledge on these chlorine-based flame retardants and assess their importance as environmental contaminants.

’ ANALYTICAL CHEMISTRY Precautions used in the extraction and cleanup of other halogenated compounds in environmental samples also apply to DP and its analogs. These precautions include using high purity solvents, oven-baked glassware, appropriate internal standards and procedural blanks, and protecting samples from UVlight.1,3,9,12,13 Clean gas chromatographic injection port liners, to mitigate in situ formation of dechlorinated products, are also an important consideration in DP analysis.12 The in situ formation of dechlorination products should be monitored using ions corresponding to [M-ClþH]
and [M-2Clþ2H]
in the electron capture negative ionization (ECNI) mass spectrometry mode; it is difficult to use the electron impact (EI) mode because of the low intensities of these ions. Soxhlet and pressurized fluid extraction have been used for extracting DP from solid environmental samples, and solid phase extraction using a nonpolar stationary phase has been used for extracting DP and its analogs from water.7 For lipid containing samples, acid treatment or gel permeation chromatography have been used for removing lipids from the sample extract, and silica and Florisil have been used for separating DP from other halogenated compounds. However, acid treatment will likely confound analysis of the DP monoadducts due to attack at the free double bond. Capillary GC columns with nonpolar stationary phases interfaced to a mass spectrometer operating in the ECNI mode are the most common approach for the detection and quantification of DP.1,9,12
14 While some DP analogs have been studied under EI conditions, this is not the optimum method for the quantitative determination of DP in environmental samples because of the low intensity of the molecular ion due to a retro Diels
Alder fragmentation, forming the most intense ion at m/z 270 (C5Cl6þ). This ion is a common fragment ion in the mass spectra of numerous organohalogen compounds and is not sufficiently specific to confirm the presence of DP.1 Under ECNI conditions, at low ion source temperatures (150 C), the dominant ion cluster for both syn- and anti-DP corresponds to the molecular ion at m/z 648 (or more exactly 647.7201). At 150 C, the ECNI mass spectra of both isomers also show a series

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of fragment ions with the two most dominant ions at m/z 614 and 580, corresponding to successive losses of 34 amu arising from the exchange of chlorines by hydrogens. There is also a small fragment ion at m/z 235 corresponding to the C5Cl5
ion formed from the retro Diels
Alder fragmentation of DP.1 Interestingly, the ECNI mass spectra of the syn and anti isomers become more dissimilar as the ion source temperature increases.15 For example, at 250 C, the overall intensity of the fragment ions increases appreciably in both ECNI mass spectra, while only for the anti-isomer does the molecular ion remain the most abundant ion. For the syn-isomer, the ion cluster corresponding to the loss of six chlorine atoms at m/z 438 is the most abundant ion. De la Torre et al. attribute this observation to the lower activation energy required for formation of the [M-6Cl]
fragment for the syn-isomer compared to the anti-isomer at 250 C.15 The recent interest in the structural characterization of DP analogs has prompted use of high resolution mass spectrometry for these analyses; for example, Sverko et al. identified a suite of DP analogs by monitoring molecular and fragment ions at a resolving power of 10 000 under ECNI conditions.9

’ ENVIRONMENTAL LEVELS AND MEASUREMENTS OF DECHLORANE PLUS Atmospheric Concentrations. There are a considerable number of DP measurements in the atmosphere around the North American Great Lakes. Venier and Hites16 and Hites et al.17 have presented these atmospheric concentrations, which were measured as part of the Integrated Atmospheric Deposition Network (IADN) and which cover sampling sites near the shores of the Great Lakes. Their data were obtained from 2005 to 2008, inclusive. Air samples were taken for 24 h at a frequency of once every 12 days. The sampling site locations and the geometric average of the total vapor and particle phase atmospheric DP concentrations are presented in Figure 1. These DP concentrations tend to be highest at the urban sites of Cleveland and Sturgeon Point (about 2
4 pg/m3), and the concentrations are generally much higher in the particle phase than in the vapor phase. Concentrations at the remote sites are about 10 times lower (0.2
0.5 pg/m3). All of these concentrations show strong and significant relationships to the local population density and to the distance from DP’s manufacturing site in Niagara Falls. This is clearly an indication that DP has sources associated with both its manufacturing plant in Niagara Falls and with human population density. The latter relationship may stem from the use of DP in electrical equipment, the abundance of which is proportional to population. The fraction of the anti isomer (ratio of the anti-DP concentration to the total DP concentration, or fanti) in the particle phase samples from the Great Lakes region shows a significant relationship to distance from the manufacturing site in Niagara Falls (r2 = 0.772, p < 0.05). The intercept of this regression line was close to the fraction of the anti isomer in the commercial product (0.75), but 1000 km away from this presumed source, this fraction had decreased significantly to Dec-603 > CP. Seasonal concentrations were reflective of the total organic carbon content. There has been significant research on the environmental levels of DP analogs in China, which is currently a significant producer of DP and a leading electronics manufacturer and recycler. Wang et al. measured Dec-602 concentrations of ∼2 ng/g dw in sediment from a canal near the Anpon DP manufacturing plant in Huai’an, China.8 This value is similar to

the 6 ng/g dw in Lake Ontario surface sediment as reported by Shen et al.10 Concentrations of Dec-602 in soil samples from around the plant ranged from 0.1 to 53 ng/g dw with a mean of 7 ng/g dw. Values decreased by a factor of 10 within 7.5 km of the plant. Jia et al. detected Dec-602 at 0.11 ng/g dw and Dec-603 at 0.028 ng/g dw in seashore sediments from Bohai and Huanghai in Northern China.21 Dec-604 was not detected. These concentrations are similar to those in Lakes Erie, Huron, and Superior, but significantly lower than in Lake Ontario. Atmospheric Concentrations. There are currently no reports of DP analogs in North American air samples. Wang et al. reported about 0.1 pg/m3 in the vapor phase and 4.5 ng/g in the particulate phase for Dec-602 in air samples taken 380 m from the Anpon manufacturing plant in China.8 Recently, de la Torre et al. reported results from several air samples (8 urban, 11 rural) in Spain for Dec-602, Dec-603, and CP.19 Dec-604 and 1,5DPMA were not detected. CP and Dec-603 were only detected at three sites for each compound. The average values for Dec-602 were 0.27 and 0.28 pg/m3 for rural and urban sites, respectively. These levels are four times lower than rural DP levels and 20 times lower than urban DP levels. Wastewater and Biosolids. Qi et al. detected Dec-602 in the primary effluent of a wastewater plant at 0.020 ng/L, but this compound was not detected in the influent or secondary effluent.29 Dec-602 was detected at 0.002 ng/g dw in the primary and secondary sludge; this concentrations was just above the detection limit of 0.001 ng/g dw. Dec-603 and Dec-604 were not detected in any of the samples, whereas DP was detected in all of the samples. De la Torre et al. detected Dec-602, Dec-603, and CP in biosolids from 31 Spanish wastewater treatment plants.49 Dec-604 and 1,5-DPMA were not detected in any of the samples. Levels of Dec-602, Dec-603, and CP ranged between ND and 5094

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Environmental Science & Technology 0.02 ng/g dw for all samples, except two samples for Dec-603, which were above 0.02 ng/g dw. CP was detected in only five samples. Biota Concentrations and Bioaccumulation Parameters. Shen et al. detected Dec-602, Dec-603, and Dec-604 in Great Lakes fish at levels ranging from 0.47 to 34, 0.014
0.50, and 0.063
1.3 ng/g lipid, respectively.10 The concentrations of Dec602 were higher than DP in all fish samples, indicating that Dec602 may be more bioavailable or bioaccumulative than DP, or that these organisms were exposed to higher environmental concentrations. Shen et al. also determined temporal trends for these compounds in Lake Ontario lake trout samples collected between 1979 and 2004.25 Dec-602 and Dec-603 were detected at concentrations ranging from 8 to 180 ng/g lipid and 0.03 to 0.4 ng/g lipid, respectively, and with a generally decreasing trend over that time period. Dec-604 was not detected in any of the samples. Shen et al. determined biota-sediment accumulation factors (units: kg dry weight per kg wet weight) for the DP analogs as well as for mirex using Lake Ontario lake trout samples.48 Mirex had the highest biota-sediment accumulation factor (7400) followed by Dec-602 (270) and CP (91), which were all greater than those calculated for the major PBDEs, the two DP isomers, and the other DP analogs. Zitko conducted uptake and elimination experiments in fish for mirex, DP, and some of its analogs.50 Atlantic salmon were exposed to these chemicals in water for 4 days (static conditions) and, in a separate tank, they were exposed to these chemicals in their diet for 42 days. Dec-602 was the only DP analogue (including Dec-603, Dec-604, and DP) other than mirex to be detected in the fish tissue after 4 days of aqueous exposure. There are several potential sources of error when interpreting aqueous based bioaccumulation information following the methods applied in the Zitko study, particularly for very hydrophobic chemicals;51 therefore, the aqueous exposure data are of limited utility for determining the bioaccumulation characteristics of these chemicals. From the dietary exposure test data, the whole body biological half-lives were 58, 76, 63, and 68 days for DP, Dec-602, Dec-603, and Dec-604, respectively. The half-life for total DP in salmon is similar to that reported for the syn-DP isomer in rainbow trout.14 Guerra et al. compared the levels of DP analogs in peregrine falcon eggs from Canada and Spain with aquatic and terrestrial diets (comprising primarily water-birds and terrestrial birds).39 Concentrations (ng/g lipid weight) showed the following relative pattern: 1,5-DPMA ≈ Dec-602 > Dec-603 ≈ DP > Dec-604 > Cl11DP ≈ Cl12DP. Eggs from falcons with aquatic diets generally had higher concentrations of DP analogs than those with a terrestrial diet, and Canadian falcon eggs had higher concentrations than Spanish falcon eggs. Sverko et al. determined the half-lives of 1,3-DPMA and 1,5DPMA using in vitro liver microsomes from lake trout to be 2.5 and 1.1 h, respectively, and have suggested that the lower half-life for 1,5-DPMA was the reason that it was not detected in biological samples.52 Munoz-Arnanz et al. analyzed white stork eggs from Spain.38 The monodechlorination product of DP was detected in about 10% of the samples. Neither the didechlorination product nor 1,5-DPMA were detected in any of the samples. Jia et al. analyzed 45 oysters corresponding to seashore sediments from Bohai and Huanghai in Northern China.21 Dec-602 was detected in 28 samples at an average concentration of 9.1 ng/g lipid, and Dec603 was detected in 10 samples at an average of 11 ng/g lipid.

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Dec-602 levels were similar to those reported by Shen et al. for Great Lakes fish, while Dec-603 levels were higher.25

’ PHYSICAL
CHEMICAL PROPERTIES AND MODELS OF FATE AND BIOACCUMULATION Solubility and Partitioning. There is a lack of measured physical
chemical property data for DP and its analogs. Thus, quantitative structure
activity relationship (QSAR) models were used to estimate water solubilities (SW), vapor pressures (PS), octanol
water partition coefficients (KOW), air
water partition coefficients (KAW), and octanol-air partition coefficients (KOA) (see the SI). The models indicate that all of these chemicals are superhydrophobic (SW < 10 ng/L; log KOW > 7) with very low vapor pressures (PS < 10
6 Pa), and as a result, there are technical challenges in obtaining reliable measurements of their physical
chemical properties. Environmental Half-Lives, Persistence, And Long-Range Transport Potential. Available screening-level models indicate that these chemicals are not readily biodegradable and that the half-lives in water, soil, and sediment are greater than screening criteria used in the Stockholm Convention (see the SI).53 The modeled half-lives in air for some of these chemicals are less than the Stockholm Convention screening criteria (i.e., < 2 days); however, these half-lives are predicted for the gas phase only and use default OH radical concentrations.54 Due to the low vapor pressures of these chemicals, DP and its analogs are expected to be associated with particles in the atmosphere (i.e., > 99% particle bound), and this expectation is supported by the monitoring data. Sorption to particles may slow reaction rates; therefore, the actual half-lives in the air may be greater, facilitating the long range transport of these chemicals on particles. Other chemicals with low vapor pressures, such as decabromodiphenyl ether, show significant long-range atmospheric transport potential.55 The OECD Tool56 was used to calculate the characteristic travel distance and overall persistence of DP and DP analogs and to compare these estimates with benchmark chemicals (see SI). The results of the OECD Tool are uncertain because the environmental half-lives for air, water, and soil required as input for the OECD Tool calculations are largely from QSAR estimates; however, in general, the OECD Tool results suggest that DP and its analogs have transport and persistence properties similar to many listed Stockholm Convention pollutants. The screening-level model results also support available monitoring data indicating the long-range transport potential of these chemicals. Biotransformation Half-Lives and Bioaccumulation. Biotransformation half-lives in fish were estimated from an in vivo depuration test for DP14,57 and from a screening-level QSAR model58 (see SI). These biotransformation half-lives are slow and comparable to biotransformation half-lives associated with chemicals that are known to biomagnify and bioaccumulate in aquatic food webs.58 Bioaccumulation factors (BAFs; L-water/ kg-wet weight) calculated by a screening-level QSAR model show that steady-state BAFs in fish are >5000 for DP and its analogs (see SI).59 The biotransformation half-lives and high BAFs predicted by the screening-level models are in general agreement with the measured half-life, BMF, and TMF data.13,14 Collectively, these data suggest that DP and some of its analogs have the potential to bioaccumulate in aquatic food webs. The predicted BAF values exceed bioaccumulation hazard criteria outlined in the Stockholm Convention (i.e., > 5000).53 BAFs for 5095

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Environmental Science & Technology these chemicals are difficult to measure because water concentrations in the environment are usually close to or below detection limits, and the dissolved (bioavailable) fraction of the chemical in the water is also very low. For example, the bioavailable fraction (i.e., concentration dissolved/total concentration measured) for DP (log KOW ∼9) is estimated to be about 0.005 based on typical environmental concentrations of dissolved and particulate organic carbon.59 Air
surface Exchange. Wang and co-workers measured both air and soil samples collected concurrently near a DP manufacturing facility.8 DP concentrations in both the gas and particle phases for three air samples were measured for three consecutive days in October, 2009, and the results are depicted in SI Figure SI-5. It is interesting to note that, while the levels of particle-bound DP in air during the three sampling days varied widely (7330
26 300 pg/m3) due to local wind direction and speed, the levels of gas-phase DP were quite stable (390
430 pg/m3). Furthermore, the values of fanti for gas-phase DP was 0.74 ( 0.04, close to that in soil (0.78 ( 0.11), but higher than those for particle phase DP (0.64 ( 0.01), which is close to that of DP produced by the Chinese manufacturer. This may indicate different sources of DP in the two phases; therefore, we suggest that the particle-phase DP in air measured near this DP manufacturer originated from the DP production facility, while the gas-phase DP originated from soil volatilization. In order to explore this further, the ratio of CA/CS was calculated. If we use DP’s log KOA value from SI Table SI-4, we get an equilibrium ratio of (see SI for details) CA =CS  3:2  10
5 where CA is the DP concentration in air (in pg/m3) and CS is the DP concentration in soil (in pg/g dw). The concentration of DP in a soil sample collected nearest the air sampler was 13 400 ng/g dw. Using the above equation, air concentrations of DP in the gas-phase at equilibrium were calculated to be 430 pg/m3, which is close to the measured values (390
430 pg/m3). Air
water exchange was also studied using the data measured by M€oller et al. in the marine boundary layer air and in surface seawater from the East Greenland Sea and in the Northern and Southern Atlantic Oceans.7 The mean gas-phase DP concentrations in air and in the dissolved-phase in the seawater were, respectively, 0.12 pg/m3 and 0.009 pg/L in the East Greenland Sea and 0.028 pg/m3 and 0.044 pg/L, respectively, along the Atlantic transect. These concentrations suggest that the fugacity fraction (see the SI) is 0.96 in the East Greenland Sea and 0.92 along the Atlantic transect. These values are near unity and indicate net gaseous deposition of DP to seawater and support the importance of long-range atmospheric transport as a major pathway for DP to reach the Arctic and Antarctica.

’ FUTURE RECOMMENDATIONS AND CONCLUSIONS Dechlorane Plus is globally ubiquitous; however, due to a lack of monitoring data, similar conclusions cannot yet be made about the DP analogs. DP is present in remote regions far from manufacturing facilities. DP and some of its analogs are bioaccumulative and persistent in some environmental media; however, while persistence and bioaccumulation have been sufficiently demonstrated for DP (in particular), reliable toxicity data and further research evaluating the potential for significant adverse effects are needed before these chemicals can be considered for Annex D evaluation under the United Nations Stockholm

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Convention on Persistent Organic Pollutants. We suggest future work in the following areas: • Laboratory biota-sediment accumulation factor measurements to quantify the transfer and availability of DP and its analogs from sediments (both aged and spiked) to representative benthic organisms. • Use of passive samplers to estimate dissolved-phase concentrations of DP and its analogs in sediment pore water and in the overlying water column. • Dietary bioaccumulation studies of DP analogs to obtain key bioaccumulation parameters such as dietary assimilation efficiency, BMF, and depuration half-lives that could then be used to estimate biotransformation half-lives. This information could reduce uncertainty in parametrizing and applying food web models for exposure and risk estimates for lower and upper trophic level organisms. • Environmental degradation studies of DP and its analogs to determine medium-specific half-lives. • More environmental measurements of DP and its analogs are needed, particularly in Europe; it is important to fully establish the environmental distribution of these chemicals. • Acute and chronic toxicity studies on DP and its analogs are needed; however, due to the low water solubilities of these compounds, toxicity tests for aquatic species will require dietary-based dosing strategies.

’ ASSOCIATED CONTENT

bS

Supporting Information. Tables include chemical identifications; SMILES notations; molar masses; melting points; water solubilities; vapor pressures; and air
water, octanol
water, and octanol-air partition coefficients. Figures include boxplots comparing concentrations in Great Lakes tributary sediments; characteristic travel distances; transfer efficiencies, overall persistences; and screening-level bioaccumulation factors. This material is available free of charge via the Internet at http:// pubs.acs.org. Organohalogen Compound papers can be downloaded from www.Dioxin20XX.org.

’ AUTHOR INFORMATION Corresponding Author

*E-mail: [email protected].

’ ACKNOWLEDGMENT R.A.H. thanks Marta Venier and Amina Salamova for helpful comments. Y.F.L. expresses his appreciation to all members of the International Joint Research Center for Persistent Toxic Substances for their work on the Dechloranes. J.A.A. acknowledges the Natural Sciences and Engineering Research Council (NSERC) of Canada for postdoctoral funding. ’ REFERENCES (1) Hoh, E.; Zhu, L.; Hites, R. A. Dechlorane Plus, a chlorinated flame retardant, in the Great Lakes. Environ. Sci. Technol. 2006, 40, 1184–1189. (2) Betts, K. S. A new flame retardant in the air. Environ. Sci. Technol. 2006, 40, 1090–1091. (3) Gauthier, L. T.; Hebert, C. E.; Weseloh, D. V. C.; Letcher, R. J. Current-use flame retardants in the eggs of herring gulls (Larus argentatus) from the Laurentian Great Lakes. Environ. Sci. Technol. 2007, 41, 4561–4567. 5096

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Environmental Science & Technology (4) Zhu, J.; Feng, Y. F.; Shoeib, M. Detection of Dechlorane Plus in residential indoor dust in the city of Ottawa, Canada. Environ. Sci. Technol. 2007, 41, 7694–7698. (5) Ren, G. F.; Yu, Z. Q.; Ma, S. T.; Chen, L. G.; Luo, X. F.; Sheng, G. Y.; Fu, J. M. Dechlorane Plus in in-and outdoor air of an urban city in southern China. Organohalogen Compd. 2010, 72, 852–855. (6) Qiu, X. H.; Hites, R. A. Dechlorane Plus and other flame retardants in tree bark from the northeastern United States. Environ. Sci. Technol. 2008, 42, 31–36. (7) M€oller, A.; Xie, Z.; Sturm, R.; Ebinghaus, R. Large-scale distribution and transport of Dechlorane Plus in air and sea water of the Arctic to Antarctic. Environ. Sci. Technol. 2010, 44, 8977–8982. (8) Wang, D. G; Yang, M.; Qi, H.; Sverko, E.; Ma, W. L; Li, Y. F; Alaee, M.; Reiner, E. J.; Shen, L. An Asia-specific source of Dechlorane Plus: Concentration, isomer profiles, and other related compounds. Environ. Sci. Technol. 2010, 44, 6608–6613. (9) Sverko, E.; Reiner, E. J.; Tomy, G. T.; McCrindle, R.; Shen, L.; Arsenault, G.; Zaruk, D.; MacPherson, K. A.; Marvin, C. H.; Helm, P. A.; McCarry, B. E. Compounds structurally related to Dechlorane Plus in sediment and biota from Lake Ontario (Canada). Environ. Sci. Technol. 2010, 44, 574–579. (10) Shen, L.; Reiner, E. J.; MacPherson, K. A.; Kolic, T. M.; Sverko, E.; Helm, P. A.; Bhavsar, S. P.; Brindle, I. D.; Marvin, C. H. Identification and screening analysis of halogenated norbornene flame retardants in the Laurentian Great Lakes: Dechloranes 602, 603, and 604. Environ. Sci. Technol. 2010, 44, 760–766. (11) The European Commission report on potential alternatives to deca-BDE. http://ecb.jrc.ec.europa.eu/documents/Existing-Chemicals/ Review_on_production_process_of_decaBDE (accessed January 16, 2011). (12) Sverko, E.; Tomy, G. T.; Marvin, C. H.; Zaruk, D.; Reiner, E.; Helm, P. A.; Hill, B.; McCarry, B. E. Dechlorane Plus levels in sediment of the lower Great Lakes. Environ. Sci. Technol. 2008, 42, 361–366. (13) Tomy, G. T.; Pleskach, K.; Ismail, N.; Whittle, D. M.; Helm, P. A.; Sverko, E.; Zaruk, D.; Marvin, C. H. Isomers of Dechlorane Plus in Lake Winnipeg and Lake Ontario food webs. Environ. Sci. Technol. 2007, 41, 2249–2254. (14) Tomy, G. T.; Thomas, C. R.; Zidane, T. M.; Murison, K. E.; Pleskach, K.; Hare, J.; Arsenault, G.; Marvin, C. H.; Sverko, E. Examination of isomer specific bioaccumulation parameters and potential in vitro hepatic metabolite of syn- and anti-Dechlorane Plus isomers in juvenile rainbow trout (Oncorhynchus mykiss). Environ. Sci. Technol. 2008, 42, 5562–5567. (15) de la Torre, A.; Concejero, M. A.; Sverko, E.; Shen, L.; Martinez, M. A.; Reiner, E.; Alaee, M. Effect of source temperature on the ECNI/MS spectra of Dechlorane Plus isomers. Organohalogen Compd. 2010, 72, 1737–1740. (16) Venier, M.; Hites, R. A. Flame retardants in the atmosphere near the Great Lakes. Environ. Sci. Technol. 2008, 42, 4745–4751. (17) Hites, R. A.; Salamova, A.; Venier, M. Dechlorane Plus in Great Lakes air. Organohalogen Compd. 2010, 72, 423–426. (18) Ren, N.; Sverko, E.; Li, Y. F; Zhang, Z.; Harner, T.; Wang, D.; Wan, X.; McCarry, B. E. Levels of isomer profiles of Dechlorane Plus in Chinese air. Environ. Sci. Technol. 2008, 42, 6476–6480. (19) de la Torre, A.; Pacepavicius, G.; Shen, L.; Reiner, E.; Jimenez, B.; Alaee, M.; Martinez, M. A. Dechlorane Plus and related compounds in Spanish air. Organohalogen Compd. 2010, 72, 929–932. (20) Sverko, E.; Harner, T.; Lee, S. C.; McCarry, B. E. Dechlorane Plus in the Global Atmospheric Passive Sampling (GAPS) study. Presented at Dioxin, San Antonio, TX, September 12
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