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ABSTRACT: Highly brominated flame retardant compounds have relatively low bioavailability, but some of these compounds have been shown to be of environmental concern. Tetradecabromodiphenoxybenzene (TDBDPB) contains 14 bromine atoms and is the major component of commercial flame retardant mixtures such as the recently phased out SAYTEX 120. The chemical stability of TDBDPB has not been reported. We demonstrated that TDBDPB can photolytically undergo step-wise reductive debromination that follows first-order kinetic degradation models when exposed to ultraviolet (UV) or natural sunlight radiation, and when dissolved in the solvents tetrahydrofuran, methanol or n-hexane. Photolytic degradation half-lives of TDBDPB ranged from 98 to 169 min, 0.78 to 0.83 min, 1.0 to 1.8 min and 4.9 to 7.4 min when exposed to UV-A, -B and -C and natural sunlight, respectively. However, the TDBDPB half-lives when exposed to UV-B and especially UV-C are likely underestimated since solutions were in borosilicate glass vials during irradiation, resulting from increasingly lower % transmittance of λ < 300 nm. Neat technical TDBDPB powder exposed to UV-B and -C radiation also produced less brominated products, although the rate was much slower as compared to when in solution. Exposure of TDBDPB solutions to natural sunlight generated a number of polybrominated diphenoxybenzene (PBDPB) photolysis products, among which the Br(4) to Br(7) PBDPBs were the most frequently observed and estimated to be most concentrated. As evidenced by the TDBDPB half-lives and the degree of debrominated by-product formation, the findings showed that the fraction of the absorbed irradiation that was of sufficient energy to break C-Br bonds of TDBDPB and lesser brominated PBDPBs increased from UV-B or -C to UV-A. Coincidentally, we recently reported on the presence of several Br(4) to Br(6) methoxylated PBDPBs in the Great Lakes herring gull eggs, which may be linked to a TDBDPB source via photolytic degradation to more bioavailable and persistent debromination products.
Environmental Science & Technology 01/2013; · 4.80 Impact Factor
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ABSTRACT: The metabolism of α- and β-isomers of the flame retardant chemical tetrabromoethylcyclohexane (TBECH) was investigated using a model in vitro enzyme-mediated biotransformation assay based on rat liver microsomes. In enzymatically active assays, concentrations of both α- and β-TBECH isomers were equally depleted by about 40% and in a time-dependent fashion over a 60-min assay incubation period, and determined by GC-MS(ECNI) analysis. No such depletion was observed in nonenzymatically active control assays. After the full 60-min assay incubation period, debrominated TBECH metabolites were not detected by GC-MS(ECNI), and suggested that enzyme-mediated debromination of TBECH did not occur via cyctochrome P450 enzyme-mediated catalysis or that the rate of TBECH metabolism in vitro was too slow. In the enzymatically active assays, but not in the nonezymatically active control assays, α- and β-monohydroxy-TBECH (OH-TBECH), dihydroxy-TBECH ((OH)(2)-TBECH), and some additional compounds with molecular formulas of C(8)H(13)Br(3)O(2) and C(8)H(11)Br(3)O(2) were identified by LC-Q-ToF-MS. Two unique sets of OH-TBECH and (OH)(2)-TBECH metabolites were derived from both α- and β-TBECH isomers. The LC-ESI(-)-MS/MS peak areas of all four OH-TBECH and (OH)(2)-TBECH metabolites increased at a comparable rate in a time-dependent manner over a 60-min assay incubation period. This study demonstrated that metabolism via hydroxylation can occur in vitro for α- and β-TBECH. These results underscore the importance of understanding the biological fate of TBECH and the possible implications on the health and TBECH levels in exposed wildlife and in the environment.
Environmental Science & Technology 08/2012; 46(18):10263-70. · 4.80 Impact Factor
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ABSTRACT: We recently reported the discovery and identification of novel methoxylated polybrominated diphenoxybenzenes (MeO-PBDPBs) in herring gulls eggs from the Laurentian Great Lakes of North America. We presently investigated the temporal changes (1982-2010) in MeO-PBDPB concentrations and congener patterns, as well as chemical tracers of diet (ratios of carbon and nitrogen stable isotopes), in egg pool homogenates from five selected colony sites across the Great Lakes. Egg pool homogenates from the Channel-Shelter (C-S) Island (Lake Huron) contained ∑MeO-PBDPB concentrations orders of magnitude greater than those from other colonies, suggesting potential point contamination sources nearby. In the C-S Island egg pools, concentrations increased from the initial study year (31 ng/g wet weight) and peaked around the late 1990s, followed by a general decline until 2010. Over the period, concentrations generally increased in eggs from Fighting Island (Lake Erie), Toronto Harbour (Lake Ontario) and Big Sister Island (Lake Michigan) colonies, whereas the levels in Agawa Rock (Lake Superior) declined. Although other factors likely exist, changes over time in the carbon and nitrogen isotope tracers reflected a shift of the gull diet from aquatic to more terrestrial origins, and suggested this diet shift partially accounted for the temporal changes of ∑MeO-PBDPB levels in eggs from most colonies. The ratio of Br(6)- to Br(5)-MeO-PBDPB congeners generally decreased over time in the colonies at Channel-Shelter Island, Fighting Island and Agawa Rock. This suggested that Br(5)- versus Br(6)-MeO-PBDPB congeners and/or possibly their nonmethoxylated and higher brominated precursors may have been more abundant in diets of terrestrial origin. Notably, these MeO-PBDPB congeners are not "emerging" brominated substances, but rather "recently discovered" contaminants since, as of 2011, ∑MeO-PBDPB concentrations have been constantly in the range of 30-100 ng/g ww for at least the last 30 years.
Environmental Science & Technology 08/2012; 46(17):9456-63. · 4.80 Impact Factor
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ABSTRACT: Numerous triester organophosphate flame retardants (OPFRs) have been used for several decades and continue to be used in a variety of commercial products. We developed a sensitive quantitative method for the analysis of, seven non-halogenated, three chlorinated and two brominated OPFRs of known or possible environmental relevance in herring gull eggs. This method is based on a simple two-step sample extraction followed by liquid chromatography-electrospray ionization(+)-tandem mass spectrometry. Instrumental detection limits and method limits of quantification (MLOQs) among the 12 OPFRs ranged from 0.01 to 0.12 ng/mL and 0.06 to 0.20 ng/g, respectively. The mean OPFR recovery efficiencies of replicate analyses (n=6) were very quantitative and ranged from 89% to 104%, with the two brominated OPFRs being somewhat lower but reproducible, i.e., 67% and 72%, respectively. Essentially negligible matrix effects were indicated by a standard addition approach that revealed mean percent signal recoveries (n=5 replicates) of 89-106% for most OPFRs. In the analysis of n=13 herring gull eggs from the Channel-Shelter Island colony (Lake Huron), tris(2-chloroisopropyl) phosphate (<MLOQ - 4.1 ng/g wet weight, ww), tris(2-chloroethyl) phosphate (<MLOQ - 0.6 ng/g ww) and tris(2-butoxyethyl) phosphate (<MLOQ - 2.2 ng/g ww) were detected and/or quantified.
Journal of chromatography. A 12/2011; 1220:169-74. · 4.19 Impact Factor
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ABSTRACT: An increasing number of brominated flame retardants and other brominated substances are being reported in herring gull eggs from the Laurentian Great Lakes basin. Yet, in extracts from gulls' eggs, numerous bromide anion response peaks in electron capture negative ion (ECNI) mass chromatograms remain unidentified. Using archived herring gull egg homogenates, we characterize the structures of three major and three minor, new and unique brominated substances. After extensive cleanup and separation to isolate these substances from the extracts, high-quality ECNI and electron impact (EI) mass spectra revealed fragmentation patterns consistent with congeners of methoxylated polybrominated diphenoxybenzene (MeO-PBDPB), where four congeners contained five bromines and the other two contain four and six bromines, respectively. Optimized, semiquantitative analysis revealed sum concentrations of the MeO-PBDBP congeners ranged from <0.2 to 36.8 ng/g ww in pooled egg homogenates (collected in 2009) from fourteen herring gull colony sites across the Great Lakes, with the highest concentration being for Channel-Shelter Island in Saginaw Bay (Lake Huron). To our knowledge, there are no published reports on the environmental presence and sources of MeO-PBDPBs. We hypothesize that these MeO-PBDPBs are degradation products of the polybrominated diphenoxybenzenes, for example, tetradecabromodiphenoxybenzene (currently marketed as SAYTEX 120) or polybromo 3P2E. MeO-PBDPBs in Great Lakes herring gull eggs indicates their bioaccumulation potential, and raises concerns about their origin, environmental behavior and influences on wildlife and environmental health.
Environmental Science & Technology 10/2011; 45(22):9523-30. · 4.80 Impact Factor
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ABSTRACT: Several organophosphate triesters are widely used as flame retardants and can be metabolized to dibutyl (DBP), diphenyl (DPhP), di(2-ethylhexyl) (DEHP) and di(1,3-dichloro-2-propyl) (or bis(1,3-dichloro-2-propyl); DDCPP) phosphoric acid, respectively. A highly sensitive liquid chromatography-electrospray ionization(+)-triple quadrupole mass spectrometry (LC-ESI(+)-QQQ-MS/MS) based analysis method was presently developed. In this method the target compounds were separated with a C(18)-based reversed phase LC column, and decamethonium hydroxide (dicatonic reagent) was introduced post-LC to form ion-pairs, which were subsequently detected by ESI(+). For the phosphate acid diester ion-pairs, the mass spectra showed the most abundant ion to be [(CH(3))(2)N(CH(2))(10)N(CH(3))(3)](+), with lesser abundances of [[M-H](-)[(CH(3))(3)N(CH(2))(9)CH(2)](2+)](+) and [CH(2)CH(CH(2))(8)N(CH(3))(3)](+). For DDCPP, the fragment ions of [[Cl](-)[(CH(3))(3)N(CH(2))(10)N(CH(3))(3)](2+)](+) and [[Cl](-)[(CH(3))(3)N(CH(2))(9)CH(2)](2+)](+) could also be observed. The limits of quantitation (LOQs) by LC-ESI(+)-MS/MS (based on multiple reaction monitoring) were 0.14, 0.03, 0.14 and 0.02 ng/mL for DPhP, DBP, DDCPP and DEHP, respectively. The response was highly linearly correlated (r>0.995) with concentration over the range of the LOD to 1000 ng/mL. The matrix effect on ESI+ was negligible for the samples in experiment of in vitro metabolism using rat liver microsomes.
Journal of chromatography. A 09/2011; 1218(44):8083-8. · 4.19 Impact Factor
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ABSTRACT: In the present study, groups of juvenile Atlantic salmon (Salmo salar) were fed gelatine capsules containing fish-food spiked with PFOA or PFOS (0.2 mg kg(-1) fish) and solvent (methanol). The capsules were given at days 0, 3 and 6. Blood, liver and whole kidney samples were collected prior to exposure (no solvent control), and at days 2, 5, 8 and 14 after exposure (Note: that day 14 after exposure is equal to 7d recovery period). We report on the differences in the tissue bioaccumulation patterns of PFOS and PFOA, in addition to tissue and compound differences in modulation pattern of biotransformation enzyme genes. We observed that the level of PFOS and PFOA increased in the blood, liver and kidney during the exposure period. Different PFOS and PFOA bioaccumulation patterns were observed in the kidney and liver during exposure- and after the recovery periods. Particularly, after the recovery period, PFOA levels in the kidney and liver tissues were almost at the control level. On the contrary, PFOS maintained an increase with tissue-specific differences, showing a higher bioaccumulation potential (also in the blood), compared with PFOA. While PFOS and PFOA produced an apparent time-dependent increase in kidney CYP3A, CYP1A1 and GST expression, similar effects were only temporary in the liver, significantly increasing at sampling day 2. PFOA and PFOS exposure resulted in significant decreases in plasma estrone, testosterone and cortisol levels at sampling day 2, and their effects differed with 17α-methyltestostrerone showing significant decrease by PFOA (also for cholesterol) and increase by PFOS. PFOA significantly increased estrone and testosterone, and no effects were observed for cortisol, 17α-methyltestosterone and cholesterol at sampling day 5. Overall, the changes in plasma steroid hormone levels parallel changes in CYP3A mRNA levels. Given that there are no known studies that have demonstrated such tissue differences in bioaccumulation patterns with associated differences in toxicological responses in any fish species or lower vertebrate, the present findings provide some potential insights and basis for a better understanding of the possible mechanisms of PFCs toxicity that need to be studied in more detail.
Chemosphere 02/2011; 83(8):1035-44. · 3.21 Impact Factor
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ABSTRACT: Tetrabromobisphenol-A-bis(2,3-dibromopylether) (TBBP-A-dbpe), tetrabromobisphenol-A-bis(allyl ether) (TBBP-A-ae), and tetrabromobisphenol-S-bis(2,3-dibromopropyl ether) (TBBP-S-dbpe) are derivatives of tetrabromobisphenol-A (TBBP-A), and are all used as brominated flame retardants (BFRs). Using high-performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry with atmospheric pressure photoionization (APPI) in the negative mode (LC-APPI(-)-Q-TOF-MS) and the novel use of pure acetone as dopant and LC mobile phase, full scan mass spectra showed that for these BFRs the dominant isotopic ion cluster was [M + O₂](-), and with other lesser abundant [M + O₂ - HBr](-), and [M - H](-) fragment ions. Subsequently, highly sensitive quantification of TBBP-A-dbpe, TBBP-A-ae, and TBBP-S-dbpe was accomplished via LC-triple quadrupole mass spectrometry with APPI(-) (LC-APPI(-)-MS/MS) via multiple ion monitoring based on the [M + O₂](-) > [Br](-) transition. Low to sub ng/g (wet weight (w.w.)) method limits of detection (LODs) were achieved, i.e., 0.07, 0.03, and 1.28 ng/g w.w. for TBBP-A-dbpe, TBBP-A-ae, and TBBP-S-dbpe, respectively. A variety of herring gull eggs were screened for these BFRs. The eggs were collected during 2008-2009 from several colony sites in the eastern Laurentian Great Lakes (Ontario) and in the St. Lawrence River (Québec). All egg samples had TBBP-S-dbpe concentrations below the LOD, and TBBP-A-ae and TBBP-A-dbpe were quantifiable in 67%-83% of the samples at concentrations up to 0.56 ng/g wet weight. Thus, TBBP-A-ae and TBBP-A-dbpe are present in herring gull eggs from these populations, bioaccumulate in the herring gull food chain, and are transferred from gull to egg.
Environmental Science & Technology 10/2010; 44(22):8615-21. · 4.80 Impact Factor
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ABSTRACT: Prior to its recent phaseout, perfluorooctane sulfonate (PFOS) was produced by electrochemical fluorination processes, which yielded technical mixtures composed of linear isomer (∼65-79%) and several branched isomers (∼21-35%). Because PFOS can biomagnify in wildlife, birds that occupy higher trophic levels are at increased risk of exposure. We hypothesized that the pharmacokinetic properties of PFOS are isomer-specific in developing chicken (Gallus gallus domesticus) embryos exposed to technical grade PFOS (T-PFOS). In the present study, T-PFOS was composed of 62.7% linear isomer (L-PFOS), and 37.3% branched isomer, including six mono(trifluoromethyl)-branched isomers and four bis(trifluoromethyl)-branched isomers. Concentrations of 0.1, 5, or 100 µg/g of T-PFOS were injected into the air cell of chicken eggs prior to incubation. After pipping, compared with T-PFOS, the PFOS isomer profile in embryonic liver tissue for the 0.1 µg/g dose group showed 21% enrichment in the proportion of L-PFOS with a corresponding decrease in the proportion of branched isomers. Not all branched isomers were discriminated against at equal rates. The proportion of two mono(trifluoromethyl)-branched isomers and three bis(trifluoromethyl)-branched isomers decreased to a greater degree than other branched isomers. In contrast, the mono-branched isomer, P6MHpS, was overrepresented in the low-dose group. In the higher dose groups, L-PFOS was still enriched but only by approximately 10%, which indicated a dose-dependent change in isomer composition relative to T-PFOS. These results show that accumulation of PFOS in chicken embryo livers is dependent on the presence and position of branches on the alkyl backbone. This supports the hypothesis that the pharmacokinetics of PFOS are isomer-specific in biota, and may help explain why wildlife PFOS burdens are dominated by L-PFOS relative to T-PFOS mixtures.
Environmental Toxicology and Chemistry 10/2010; 30(1):226-31. · 2.81 Impact Factor
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ABSTRACT: Hexabromocyclododecane (HBCD) is an additive flame retardant used primarily in polystyrene foams. HBCD is a persistent contaminant that has been detected in abiotic and biotic matrices, including wild avian species. The toxicological implications of exposure are not well characterized. We recently identified molecular end points responsive to HBCD exposure in chicken embryonic hepatocytes (CEHs) including genes involved in xenobiotic metabolism, thyroid hormone transport, and lipid metabolism. In the current study, a technical mixture of HBCD (HBCD-TM), comprising 12% alpha-, 11% beta-, and 77% gamma-stereoisomers, was injected into the air cell of chicken eggs prior to incubation. Embryonic viability to pipping, isomer-specific HBCD accumulation, and hepatic mRNA expression of the genes identified in the in vitro study were determined. Concentrations of 100 and 10,000 ng/g decreased pipping success while 50, 300, and 1000 ng/g had no effect. In contrast to HBCD-TM, the isomeric composition in liver tissue was significantly different for alpha- (31%) and gamma-HBCD (61%) demonstrating that isomer-specific processes were occurring in the egg and/or developing embryo. Exposure to 1000 ng/g HBCD-TM significantly upregulated cytochrome P450 (CYP) 2H1, CYP3A37, uridine 5'-diphospho-glucuronosyltransferase, and deiodinase 2, while liver fatty acid-binding protein and insulin-growth factor 1 expression were significantly decreased at 100 and 10,000 ng/g, respectively. The alterations in hepatic mRNA levels were in concordance with those observed in CEH highlighting the utility of both approaches for identifying molecular mechanisms of action. Research on the effects of HBCD in wild avian species is warranted.
Toxicological Sciences 03/2010; 115(2):492-500. · 4.65 Impact Factor
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ABSTRACT: Pharmaceuticals discharged in municipal wastewater are of emerging concern because of their potential for inducing biological effects in aquatic organisms. Selective serotonin reuptake inhibitors (SSRIs), pharmaceuticals prescribed to treat chronic depression, have been detected in receiving and wastewaters. Fluoxetine is a highly prescribed model SSRI used to assess impacts of antidepressants on aquatic organisms. In this study, in vitro hepaticfluoxetine metabolism was determined in several model fish species: rainbow trout, goldfish, zebrafish and killifish. Incubation of fluoxetine with hepatic microsomes from trout pre-treated with carbamazepine showed a time-dependant loss of fluoxetine, concomitant with an increase in norfluoxetine, the major mammalian demethylated metabolite. However, fluoxetine was not well metabolized in reactions with hepatic microsomes from untreated fish. Fluoxetine loss was greater than norfluoxetine production, indicating that norfluoxetine is not the predominant fluoxetine biotransformation product in fish. Furthermore, norfluoxetine was often undetected, possibly indicating that fluoxetine demethylation is a minor metabolic pathway in fish. Inter-species differences in fluoxetine metabolism were not evident because of high intra-species variability, although killifish appeared to have the highest hepatic metabolic capacity for fluoxetine. Fluoxetine metabolism in mammals is catalyzed by cytochrome P450 (CYP) enzymes. Trout were exposed to knownCYP inducers, carbamazepine and 3-methylcholanthrene, to assess potential induction of hepatic fluoxetine metabolism. Microsomes from 3-methylcholanthrene treated fish did not induce detectable changes in fluoxetine concentrations in vitro, indicating that fish CYP1s are not involved in fluoxetine metabolism; the CYPs involved are still unclear. Identification of metabolites other than norfluoxetine warrants further investigation.
Chemosphere 02/2010; 79(1):26-32. · 3.21 Impact Factor
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ABSTRACT: Antidepressants are a widely prescribed group of pharmaceuticals that can be biotransformed in humans to biologically active metabolites. In the present study, the distribution of six antidepressants (venlafaxine, bupropion, fluoxetine, sertraline, citalopram, and paroxetine) and five of their metabolites was determined in a municipal wastewater treatment plant (WWTP) and at sites downstream of two WWTPs in the Grand River watershed in southern Ontario, Canada. Fathead minnows (Pimephales promelas) caged in the Grand River downstream of a WWTP were also evaluated for accumulated antidepressants. Finally, drinking water was analyzed from a treatment plant that takes its water from the Grand River 17 km downstream of a WWTP. In municipal wastewater, the antidepressant compounds present in the highest concentrations (i.e., >0.5 microg/L) were venlafaxine and its two demethylation products, O- and N-desmethyl venlafaxine. Removal rates of the target analytes in a WWTP were approximately 40%. These compounds persisted in river water samples collected at sites up to several kilometers downstream of discharges from WWTPs. Venlafaxine, citalopram, and sertraline, and demethylated metabolites were detected in fathead minnows caged 10 m below the discharge from a WWTP, but concentrations were all < microg/kg wet weight. Venlafaxine and bupropion were detected at very low (<0.005 microg/L) concentrations in untreated drinking water, but these compounds were not detected in treated drinking water. The present study illustrates that data are needed on the distribution in the aquatic environment of both the parent compound and the biologically active metabolites of pharmaceuticals.
Environmental Toxicology and Chemistry 01/2010; 29(1):79-89. · 2.81 Impact Factor
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Analytical Chemistry 09/2009; · 5.86 Impact Factor
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ABSTRACT: Several perfluoroalkyl compounds (PFCs) are ubiquitous environmental contaminants that can biomagnify in species at high trophic levels including wild birds. Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have been detected in wild birds and are known to reduce hatching success of laboratory-exposed chicken embryos at environmentally relevant concentrations. Limited toxicity data are available regarding avian exposure to PFCs of chain lengths greater than C(8), which are of increasing environmental relevance following the recent phase-out of PFOS and PFOA. In this study, linear PFOA, perfluoroundecanoic acid (PFUdA) and perfluorodecane sulfonate (PFDS) were injected into the air cell of white leghorn chicken eggs (Gallus gallus domesticus) prior to incubation to determine effects on embryo pipping success. Furthermore, mRNA expression of key genes involved in pathways implicated in PFC toxicity was monitored in liver tissue. PFOA, PFUdA or PFDS had no effect on embryonic pipping success at concentrations up to 10 microg/g. All PFCs accumulated in the liver to concentrations greater than the initial whole-egg concentration as determined by HPLC/MS/MS. Hepatic accumulation was highest for PFOA (4.5 times) compared to PFUdA and PFDS. Cytochrome P450 1A4 and liver fatty acid binding protein mRNA expression increased after exposure to PFUdA but was only statistically significant at 10 microg/g; several orders of magnitude higher than levels found in wild bird eggs. Based on the present results for white leghorn chickens, current environmental concentrations of PFOA, PFUdA and PFDS are unlikely to affect the hatching success of wild birds.
Toxicology Letters 08/2009; 190(2):134-9. · 3.23 Impact Factor
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ABSTRACT: The present study investigated the concentrations and patterns of PBDEs and hydroxylated (OH) PBDE analogues in two ringed seal populations: less contaminated Svalbard and more contaminated Baltic Sea. Mean concentration of hepatic sigma-PBDE, which was dominated by BDE47, was six times higher in the ringed seals from the Baltic Sea compared to the seals from Svalbard. BDE47/sigma-PBDE was higher in the seals from Svalbard compared to that for Baltic seals, while the trend was opposite for BDE153 and 154. The geographical difference in contaminant pattern of PBDEs in ringed seals could be explained by biotransformation via oxidative metabolism and/or by dietary differences. OH-PBDEs were detectable in the majority of plasma samples from both locations, and dominated by bioaccumulation of naturally occurring congeners. Low levels of 3-OH-BDE47 and 4'-OH-BDE49 in the Baltic ringed seals suggested minor oxidative biotransformation of BDE47. In the Baltic seals, BDE153/sigma-PBDEs and BDE154/sigma-PBDEs increased and BDE28/sigma-PBDE decreased with increasing sigma-POP concentration, which suggests BDE153 and 154 are more persistent than BDE28. Contrasting diets of the ringed seals in these two locations may influence the PBDE congener pattern due to selective long-range transport and direct effluent emissions to Svalbard and the Baltic, respectively.
Environmental Science and Technology 06/2009; 43(10):3494-9. · 5.23 Impact Factor
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ABSTRACT: Perfluorooctane sulfonate (PFOS) is found globally as an environmental contaminant and is highly bioaccumulative in exposed biota including humans. However, there is a dearth of environmental information on the isomeric profile of PFOS, especially in biological samples, which requires suitable analysis methods for the identification and quantification of ultratrace amounts. In the present study, a novel method was developed that incorporates clean up by solid-phase extraction (SPE) WAX cartridges and in-port derivatization-gas chromatography-mass spectrometry (GC/MS) to identify and quantitatively determine linear PFOS (L-PFOS) and branched (monotrifluoromethyl and bistrifluoromethyl) isomers in PFOS technical product and in environmentally relevant biological samples. Tetrabutylammonium hydroxide (TBAH) was used for derivatization via an in situ pyrolytic alkylation reaction that occurred in the GC injector and generated butyl PFOS isomer derivatives. In addition to L-PFOS, ten branched PFOS isomers were identified in the technical product. The environmental relevance of branched PFOS isomers in addition to L-PFOS was evidenced by the presence of six branched and L-PFOS in representative herring gull and double-crested cormorant egg, and polar bear liver and plasma samples from the Great Lakes and Arctic, respectively. For all PFOS isomers in the technical product and biota samples the method demonstrated high sensitivity with the limit of detection (LOD) ranging from 0.05 to 0.25 ng/mL, with exception of L-PFOS where the LOD was 1.46 ng/mL. For the biotic samples, the method detection limits (MDLs) were slightly higher than the LODs and ranged from 0.09 to 0.46 ng/g wet weight (w.w.) with exception of L-PFOS (MDL = 6.87 ng/g w.w.).
Analytical Chemistry 05/2009; 81(11):4256-62. · 5.86 Impact Factor
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ABSTRACT: The present study investigates the concentrations and patterns of organochlorine pesticides (OCPs) and their metabolites in liver and plasma of two ringed seal populations (Phoca hispida): lower contaminated Svalbard population and more contaminated Baltic Sea population. Among OCPs, p,p'-DDE and sum-chlordanes were the highest in concentration. With increasing hepatic contaminant concentrations and activities of xenobiotic-metabolizing enzymes, the concentrations of 3-methylsulfonyl-p,p'-DDE and the concentration ratios of pentachlorophenol/hexachlorobenzene increased, and the toxaphene pattern shifted more towards persistent Parlar-26 and -50 and less towards more biodegradable Parlar-44. Relative concentrations of the chlordane metabolites, oxychlordane and -heptachlorepoxide, to sum-chlordanes were higher in the seals from Svalbard compared to the seals from the Baltic, while the trend was opposite for cis- and trans-nonachlor. The observed differences in the OCP patterns in the seals from the two populations are probably related to the catalytic activity of xenobiotic-metabolizing enzymes, and also to differences in dietary exposure.
Environmental pollution (Barking, Essex: 1987) 04/2009; 157(8-9):2428-34. · 3.43 Impact Factor
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ABSTRACT: Perfluorooctane sulfonate (PFOS) is a widely distributed industrial compound that has been detected in the eggs of various wild avian species. Laboratory studies have indicated that PFOS is embryotoxic to domestic chickens (Gallus gallus domesticus), but the mechanisms of toxicity in the developing avian embryo remain unknown. We recently demonstrated that PFOS acts as a peroxisome proliferator by causing increased expression of peroxisome proliferator activated receptor alpha (PPARalpha)-regulated genes in cultured primary chicken embryo hepatocytes. The present study examined whether PPARalpha-regulated genes were dose-dependently affected in chicken embryos exposed in ovo to PFOS. White leghorn chicken eggs were injected with 0.1, 5.0 or 100.0 microg PFOS/g egg into the air cell prior to incubation. Embryos were incubated until pipping, after which the expression of PPARalpha-regulated genes was measured in the liver tissue of surviving embryos using real-time reverse transcription polymerase chain reaction. A dose-dependent decrease in embryo pippability was observed with an LD50 of 93 microg/g (3.54 microg/g-672,910 microg/g, 95% confidence interval). Hepatic PFOS concentrations increased concomitantly with dose. The PPARalpha-regulated genes measured were peroxisomal acyl CoA oxidase, bifunctional enzyme, liver fatty acid binding protein and peroxisomal 3-ketoacyl thiolase. PFOS exposure via egg injection prior to incubation did not affect the transcriptional activity of any of the assayed PPARalpha-regulated genes at any of the doses examined in day 21 chicken embryos.
Comparative Biochemistry and Physiology Part C Toxicology & Pharmacology 01/2009; 149(4):524-30. · 2.62 Impact Factor
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ABSTRACT: Polychlorinated biphenyls (PCBs) may induce activity of hepatic enzymes, mainly Phase I monooxygenases and conjugating Phase II enzymes, that catalyze the metabolism of PCBs leading to formation of metabolites and to potential adverse health effects. The present study investigates the concentration and pattern of PCBs, the induction of hepatic phase I and II enzymes, and the formation of hydroxy (OH) and methylsulfonyl (CH3SO2=MeSO2) PCB metabolites in two ringed seal (Phoca hispida) populations, which are contrasted by the degree of contamination exposure, that is, highly contaminated Baltic Sea (n=31) and less contaminated Svalbard (n=21). Phase I enzymes were measured as ethoxyresorufin-O-deethylation (EROD), benzyloxyresorufin-O-dealkylation (BROD), methoxyresorufin-O-demethylation (MROD), and pentoxyresorufin-O-dealkylation (PROD) activities, and phase II enzymes were measured as uridine diphosphophate glucuronosyl transferase (UDPGT) and glutathione-S-transferase (GST). Geographical comparison, multivariate, and correlation analysis indicated that sigma-PCB had a positive impact on Phase I enzyme and GST activities leading to biotransformation of group III (vicinal ortho-meta-H atoms and < or =1 ortho-chlorine (Cl)) and IV PCBs (vicinal meta-para-H atoms and < or =2 ortho-Cl). The potential precursors for the main OH-PCBs detected in plasma in the Baltic seals were group III PCBs. MeSO2-PCBs detected in liver were mainly products of group IV PCB metabolism. Both CYP1A- and CYP2B-like enzymes are suggested to be involved in the PCB biotransformation in ringed seals.
Environmental Science and Technology 12/2008; 42(23):8952-8. · 5.23 Impact Factor
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ABSTRACT: A quantitative analytical method was developed to simultaneously detect fluorotelomer alcohols (6:2 FTOH, 8:2 FTOH and 10:2 FTOH) and polyfluorinated sulfonamides (perfluoro-1-octanesulfonamide (FOSA) and N-methylperfluoro-1-octanesulfonamide (NMeFOSA)) in biotic samples with liquid chromatography-atmospheric pressure photoionization mass spectrometry (LC-APPI-MS/MS). APPI mass spectra for FOSA and NMeFOSA showed that the major ionization mechanism was not photoionization, whereas for the FTOHs it was photoionization. For FTOHs, a [M+O(2)](-) ion was generated with a similar response as the deprotonated molecular ion [M-H](-). We demonstrated that FTOHs, FOSA and NMeFOSA can be measured in various biota samples using APPI with a minimized matrix effect. Using APPI, the linear response range for the FTOHs was 0-1,000 ng/mL (r(2)>0.9997), and for FOSA and NMeFOSA ranged from 0 to 250 ng/mL (r(2)>0.995). The instrument and method detect limits ranged from 0.16 to 0.63 pg and below 1 ng/g wet weight (w.w.), respectively. For the overall method applied to the test matrices, recovery efficiencies ranged from 73 to 102% for egg homogenate and 89-100% for liver tissue. The present study demonstrates for the first time that a far more response and sensitive approach for the detection and quantification of FTOHs and polyfluorinated sulfonamides is possible using APPI as opposed to electrospray ionization.
Journal of Chromatography 11/2008; 1215(1-2):92-9. · 4.53 Impact Factor
