Tetrabromobisphenol-A-Bis(dibromopropyl ether) Flame Retardant in Eggs, Regurgitates, and Feces of Herring Gulls from Multiple North American Great Lakes Locations.

The occurrence of tetrabromobisphenol-A-bis(2,3,-dibromopropyl ether) (TBBPA-BDBPE) flame retardant is generally unknown in wildlife. A highly sensitive, gas chromatography-mass spectrometry-based method was developed for TBBPA-BDBPE with optimized parameters for large volume injection. We report on TBBPA-BDBPE and temporal and spatial trends in herring gull egg pools and individuals from 14 colony sites across the Laurentian Great Lakes of North America. TBBPA-BDBPE identification was confirmed using liquid chromatography time-of-flight mass spectrometry and quantification with liquid chromatography tandem mass spectrometry analysis. TBBPA-BDBPE was quantifiable in 95% of egg pools from all colonies sampled in 2013-2017, and retrospective analysis of archived eggs (2001-2017) at 3 of the 14 colonies indicated that TBBPA-BDBPE concentrations were greater in pools from eggs collected in more recent years (

Retrospective analysis of organophosphate flame retardants in herring gull eggs and relation to the aquatic food web in the Laurentian Great Lakes of North America.

With the phase-out and regulation of some flame retardant chemicals, the production and usage of organophosphate triester flame retardants (OPFRs) has increased in recent years. In the present study, 14 OPFRs (either chlorinated, brominated or non-halogenated) were analyzed in egg pools of 10-13 individual herring gull eggs from five colonial nesting sites for 11 years spanning 1990-2010, (for a total of n=55 egg pools) in the Laurentian Great Lakes of North America (Chantry Island, Fighting Island, Agawa Rocks, Toronto Harbour and Gull Island). OPFR profiles varied slightly between colony sites and collection years. For all five sites tris(2-chloroisopropyl) phosphate (TCIPP), tris(2-chloroethyl) phosphate (TCEP) and tris(2-butoxyethyl) phosphate (TBOEP) were detected, while triphenyl phosphate (TPHP) was only quantifiable in eggs from Chantry Island and Gull Island collected in 2008 and 2010. For the 2010 egg pools, the ΣOPFR concentrations were generally low and ranged from 2.02 to 6.69 ng/g wet weight (ww). ΣOPFR concentrations in 2010 were significantly higher (p<0.05) than they were between 1990 and 2004 (4.06 vs. 1.55 ng/g ww, respectively). In a pilot examination of Great Lakes aquatic food webs, 2010-collected alewife and rainbow smelt (major herring gull fish prey) and lake trout from western Lake Erie and Ontario, only contained TBOEP at low to sub ng/g ww concentrations. These results demonstrate that low to sub-ppb concentrations of at least three OPFRs, TCIPP, TCEP and TBOEP, have been persistent in herring gull eggs from the Great Lakes for at least the past 20 years, probably bioaccumulate mainly via the fish diet, and are transferred to the eggs of exposed herring gulls.

Tris(2-butoxyethyl)phosphate and triethyl phosphate alter embryonic development, hepatic mRNA expression, thyroid hormone levels, and circulating bile acid concentrations in chicken embryos.

The organophosphate flame retardants tris(2-butoxyethyl) phosphate (TBOEP) and triethyl phosphate (TEP) are used in a wide range of applications to suppress or delay the ignition and spread of fire. Both compounds have been detected in the environment and TBOEP was recently measured in free-living avian species. In this study, TBOEP and TEP were injected into the air cell of chicken embryos at concentrations ranging from 0 to 45,400 ng/g and 0 to 241,500 ng/g egg, respectively. Pipping success, development, hepatic mRNA expression of 9 target genes, thyroid hormone levels, and circulating bile acid concentrations were determined. Exposure to the highest doses of TBOEP and TEP resulted in negligible detection of the parent compounds in embryonic contents at pipping indicating their complete metabolic degradation. TBOEP exposure had limited effects on chicken embryos, with the exception of hepatic CYP3A37 mRNA induction. TEP exposure decreased pipping success to 68%, altered growth, increased liver somatic index (LSI) and plasma bile acids, and modulated genes associated with xenobiotic and lipid metabolism and the thyroid hormone pathway. Plasma thyroxine levels were decreased at all TEP doses, including an environmentally-relevant concentration (8 ng/g), and gallbladder hypotrophy was evident at ≥ 43,200 ng/g. Tarsus length and circulating thyroxine concentration emerged as potential phenotypic anchors for the modulation of transthyretin mRNA. The increase in plasma bile acids and LSI, gallbladder hypotrophy, and discoloration of liver tissue represented potential phenotypic outcomes associated with modulation of hepatic genes involved with xenobiotic and lipid metabolism.

1,2-Dibromo-4-(1,2-dibromoethyl)-cyclohexane and tris(methylphenyl) phosphate cause significant effects on development, mRNA expression, and circulating bile acid concentrations in chicken embryos.

1,2-Dibromo-4-(1,2-dibromoethyl)-cyclohexane (DBE-DBCH; formerly abbreviated as TBECH) and tris(methylphenyl) phosphate (TMPP; formerly abbreviated as TCP) are additive flame retardants that are detected in the environment and biota. A recent avian in vitro screening study of 16 flame retardants identified DBE-DBCH and TMPP as important chemicals for follow-up in ovo evaluation based on their effects on cytotoxicity and mRNA expression in avian hepatocytes. In this study, technical mixtures of DBE-DBCH and TMPP were injected into the air cell of chicken embryos at concentrations ranging from 0 to 54,900ng/g and from 0 to 261,400ng/g, respectively, to determine effects on pipping success, development, hepatic mRNA expression, thyroid hormone levels, and circulating bile acid concentrations. Both compounds were detectable in embryos at pipping and the ß-DBE-DBCH isomer was depleted more rapidly than the α-isomer in tissue samples. DBE-DBCH had limited effects on the endpoints measured, with the exception of the up-regulation of two phase I metabolizing enzymes, CYP3A37 and CYP2H1. TMPP exposure caused embryonic deformities, altered growth, increased liver somatic index (LSI) and plasma bile acid concentrations, and altered mRNA expression levels of genes associated with xenobiotic and lipid metabolism and the thyroid hormone pathway. Overall, TMPP elicited more adverse molecular and phenotypic effects than DBE-DBCH albeit at concentrations several orders of magnitude greater than those detected in the environment. The increase in plasma bile acid concentrations was a useful phenotypic anchor as it was associated with a concomitant increase in LSI, discoloration of the liver tissue, and modulation of hepatic genes involved with xenobiotic and lipid metabolism.

In Ovo effects of two organophosphate flame retardants--TCPP and TDCPP--on pipping success, development, mRNA expression, and thyroid hormone levels in chicken embryos.

Tris(1-chloro-2-propyl) phosphate (TCPP) and tris(1,3-dichloro-2-propyl) phosphate (TDCPP) are organic flame retardants detected in the environment and biota for which avian toxicological data are limited. In this study, domestic chicken eggs were injected with TCPP or TDCPP (maximum dose = 51,600 and 45,000ng/g egg, respectively) to determine dose-dependent effects on pipping success, development, hepatic messenger RNA (mRNA) expression levels of genes associated with xenobiotic metabolism and the thyroid hormone (TH) pathway, and TH levels following 20-22 days of incubation. Neither compound reduced pipping success; however, TCPP significantly delayed pipping at 9240 and 51,600ng/g and reduced tarsus length at 51,600ng/g. TDCPP exposure resulted in significant decreases in head plus bill length, embryo mass, and gallbladder size at 45,000ng/g and reduced plasma free T4 levels at 7640ng/g. Type I deiodinase, liver fatty acid-binding protein, and cytochrome P450 (CYP) 3A37 mRNA levels were significantly induced by TCPP, whereas TDCPP induced CYP3A37 and CYP2H1. Chemical analysis of egg contents at incubation days 0, 5, 11, 18, and 19 revealed that > 92% of the injected TCPP or TDCPP concentration was detectable up to day 5; however, < 1% was detected by day 19. The observed phenotypic responses to TCPP and TDCPP exposure may be associated with disruption of the TH axis, which is critical for normal growth and development in birds. The effects of TDCPP on the gallbladder indicate that the disturbance of lipid metabolism is a likely mechanism of toxicity.

Tetradecabromodiphenoxybenzene flame retardant undergoes photolytic debromination.

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 stepwise reductive debromination that follows first-order kinetic degradation models when exposed to 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 byproduct 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.

Newly discovered methoxylated polybrominated diphenoxybenzenes have been contaminants in the Great Lakes herring gull eggs for thirty years.

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.

Alpha and beta isomers of tetrabromoethylcyclohexane (TBECH) flame retardant: depletion and metabolite formation in vitro using a model rat microsomal assay.

The metabolism of α- and ß-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 ß-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 ß-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 ß-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 ß-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.

The flame retardant ß-1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane: fate, fertility, and reproductive success in American kestrels (Falco sparverius).

Captive American kestrels (Falco sparverius) were exposed via diet during reproduction to an environmentally relevant concentration of ß-1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (ß-TBECH). The ß-TBECH isomer was injected into the food source at a daily dosing concentration of 0.239 ng/g kestrel/day (22 pairs); control birds were exposed via diet to the safflower oil vehicle only (24 pairs). Eight pairs in each group were exposed for four weeks and sacrificed for tissue analysis; the remaining pairs completed their breeding cycle, with exposure ceasing at the end of incubation (82 days). α- and ß-TBECH appeared to be rapidly metabolized and/or eliminated from fat, liver, and plasma; both isomers and potential hydroxylated metabolites of ß-TBECH (plasma) were undetected. Notwithstanding, compared to controls, pairs exposed to ß-TBECH laid fewer eggs (p = 0.019) and laid lighter eggs (successful eggs: p = 0.009). Exposed pairs also demonstrated poorer egg fertility (p = 0.035) although testis mass and histology were similar among males. Reductions in egg production and fertility resulted in decreased hatchling success (p = 0.023). The ß-TBECH-exposed pairs also produced fewer males overall (p = 0.009), which occurred concurrently with increased estradiols maternally deposited in eggs (p = 0.039). These findings demonstrate that ß-TBECH may be detrimental for breeding in wild birds receiving similar exposure levels.

Novel methoxylated polybrominated diphenoxybenzene congeners and possible sources in herring gull eggs from the Laurentian Great Lakes of North America.

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.

In vitro and in ovo effects of four brominated flame retardants on toxicity and hepatic mRNA expression in chicken embryos.

Some currently used brominated flame retardants (BFRs), such as hexachlorocyclopentadienyl-dibromocyclooctane (HCDBCO), bis(2-ethylhexyl)tetrabromophthalate (BEHTBP), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) and decabromodiphenylethane (DBDPE), are persistent organic contaminants detected in various environmental matrices, including wild birds. Data on potential toxicological and molecular responses to exposure of these BFRs are lacking for avian species. A combined in vitro/in ovo approach was used to determine the concentration-dependent effects of these BFRs on overt toxicity and hepatic messenger RNA (mRNA) expression levels of 11 transcripts in (1) primary cultures of chicken embryonic hepatocytes (CEH; all four BFRs) and (2) chicken embryos (HCDBCO and BTBPE only). Neither hepatocyte viability nor embryonic pipping success were affected by the BFRs at any of the administered concentrations (CEH: 0.001-30 µM, egg injection: 0.1-10 µg/g nominal dose). In CEH, 10 µM HCDBCO induced cytochrome P450 2H1 (CYP2H1) and CYP3A37, while CYP1A4/5 were down-regulated at all tested concentrations. In contrast, only transthyretin was down-regulated by HCDBCO in embryonic liver. There was concordance between the BTBPE-induced transcriptional responses in vitro and in ovo for CYP1A4/5 (up-regulated) and type III iodothyronine 5'-deiodinase (DIO3; down-regulated). DBDPE induced CYP1A4/5 29- and 59-fold at 0.2 µM in CEH and increased DIO1. None of the gene targets were responsive to BEHTBP exposure in CEH. The multi-tiered in vitro/in ovo screening approach was effective for assessing toxicological and molecular biological effects of these BFRs in an avian species.

The effects of Dechlorane Plus on toxicity and mRNA expression in chicken embryos: a comparison of in vitro and in ovo approaches.

Dechlorane Plus (DP) is an additive chlorinated flame retardant comprising two major isomers, syn- and anti-DP, that is used in a variety of commercial/industrial products. It has been detected in biotic and abiotic matrices including the eggs of herring gulls collected from the Laurentian Great Lakes. However, data on potential toxicological and molecular responses to exposure are lacking, especially for avian species. A combined in vitro/in ovo approach was used to determine concentration-dependent effects of DP in chicken embryonic hepatocytes (CEH) and chicken embryos following injection of DP into the air cell of eggs prior to incubation. Overt toxicity (i.e. cytotoxicity and pipping success) and mRNA expression levels of transcripts previously determined to be responsive to a brominated flame retardant were assessed in CEH and hepatic tissue. DP was not cytotoxic up to a maximum concentration of 3 µM in CEH, and no effects on pipping success were observed up to the highest nominal dose group of 500 ng/g egg. A significant shift in isomeric content of syn- and anti-DP was detected between stock solutions of the commercial mixture and hepatic tissue; the proportion of the syn-DP isomer increased from 0.34 to 0.65 with a concomitant decrease of anti-DP from 0.66 to 0.35. None of the mRNA transcripts changed as a result of in vitro or in ovo exposure to DP indicating that, although there was concordance between the two approaches, DP may evoke its toxicity through other modes of action. At current environmental exposure levels, no adverse effects of DP on embryonic viability or pathways associated with the genes assessed are predicted.

Biochemical tracers reveal intra-specific differences in the food webs utilized by individual seabirds.

Food web structure regulates the pathways and flow rates of energy, nutrients, and contaminants to top predators. Ecologically and physiologically meaningful biochemical tracers provide a means to characterize and quantify these transfers within food webs. In this study, changes in the ratios of stable N isotopes (e.g., delta(15)N), fatty acids (FA), and persistent contaminants were used to trace food web pathways utilized by herring gulls (Larus argentatus) breeding along the shores of the St Lawrence River, Canada. Egg delta(15)N values varied significantly among years and were used as an indicator of gull trophic position. Temporal trends in egg delta(15)N values were related to egg FA profiles. In years when egg delta(15)N values were greater, egg FA patterns reflected the consumption of more aquatic prey. Egg delta(15)N values were also correlated with annual estimates of prey fish abundance. These results indicated that temporal changes in aquatic prey availability were reflected in the gull diet (as inferred from ecological tracer profiles in gull eggs). Analysis of individual eggs within years confirmed that birds consuming more aquatic prey occupied higher trophic positions. Furthermore, increases in trophic position were associated with increased concentrations of most persistent organic contaminants in eggs. However, levels of highly brominated polybrominated diphenyl ether congeners, e.g, 2,2',3,3',4,4',5,5',6,6'-decabromoDE (BDE-209), showed a negative relationship with trophic position. These contrasting findings reflected differences among contaminant groups/homologs in terms of their predominant routes of transfer, i.e., aquatic versus terrestrial food webs. High trophic level omnivores, e.g., herring gulls, are common in food webs. By characterizing ecological tracer profiles in such species we can better understand spatial, temporal, and individual differences in pathways of contaminant, energy, and nutrient flow.

Temporal trends and spatial distribution of non-polybrominated diphenyl ether flame retardants in the eggs of colonial populations of Great Lakes herring gulls.

The production and use of nonpolybrominated diphenyl ether (non-PBDE), brominated flame retardant (BFR) alternatives have been on the rise, although their assessment in environmental samples is largely understudied. In the present study, several non-PBDE BFRs were found in the egg pools of herring gulls (Larus argentatus) from seven colonies in the five Laurentian Great Lakes (collected in 1982 to 2006). Of the 19 BFRs monitored, hexabromobenzene (HBB), 1,2-bis(2,4,6-tribromophe-noxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), and alpha-, beta-, gamma-, and delta-isomers of 1,2-dibromo-4-(1,2-dibromoeth-yl)cyclohexane (TBECH) were present in eggs from all the colonies with the highest detection frequencies of 100%, 54%, 9% and 97%, respectively. In 2005 and 2006 eggs, the concentrations of DBDPE were highest at three of the seven colonies (1.3 to 288 ng/g wet weight (ww)) and surpassed decabromodiphenyl ether (BDE-209). HBB (0.10 to 3.92 ng/g ww), BTBPE (1.82 to 0.06 ng/g ww), and Sigma-TBECH (0.04 to 3.44 ng/g ww; mainly the beta-isomer 52 to 100% of Sigma-TBECH) were detected at lower concentrations (and generally <

Isomers of Dechlorane Plus flame retardant in the eggs of herring gulls (Larus argentatus) from the Laurentian Great Lakes of North America: temporal changes and spatial distribution.

Dechlorane Plus (DP) is a chlorinated flame retardant (FR) comprised of two major structural isomers, syn and anti. For the Laurentian Great Lakes of North America, reports on DP have been limited to sediment and fish, not known for birds, and regardless temporal trends in Great Lakes wildlife is unknown. In the present study, syn- and anti-DP isomers were detected in egg pools spanning 1982-2006 of a Great Lakes biomonitoring species, the herring gull (Larus argentatus), from seven colonies in the five Laurentian Great Lakes. The sum (Sigma) of syn- and anti-DP concentrations were generally <15 ng g(-1) wet weight (ww) and variable depending on the colonial site and year, although Sigma-DP concentrations were generally higher post mid-1990s for all sites. Syn- and anti-DP concentrations ranged from 3.1 x 10(2) to 1.4 x 10(3)pg g(-1)ww and 1.3 x 10(2) to 4.4 x 10(3)pg g(-1)ww, respectively. There was a weak but significant (r(S)=-0.31, p<0.001) negative relationship between the Sigma-DP concentration and the distance for the only DP production facility in North America at Niagara Falls, New York. However, the fraction of the anti-DP to the Sigma-DP concentration (f(anti)) was 0.69+/-0.08 (for all seven colonies and years, n=101 pools), and there was no significant (r(S)=-0.18, p=0.07) negative relationship of f(anti) with increasing distance from the production facility at Niagara Falls, New York, which indicated that there was no temporal or spatial enrichment of either isomer relative to the commercial DP mixture. Over the past 25 years, it is clear that DP isomers have accumulated in the food web of female herring gulls with subsequent transfer during ovogenesis.

Dramatic changes in the temporal trends of polybrominated diphenyl ethers (PBDEs) in herring gull eggs from the Laurentian Great Lakes: 1982-2006.

DecaBDE is a current-use, commercial formulation of an additive, polybrominated diphenyl ether (PBDE) flame retardant composed of > 97% 2,2',3,3',4,4',5,5',6,6'-decabromoDE (BDE-209). Of the 43 PBDE congeners monitored, we report on the temporal trends (1982-2006) of quantifiable PBDEs, and specifically BDE-209, in pooled samples of herring gull (Larus argentatus) eggs from seven colonies spanning the Laurentian Great Lakes. BDE-209 concentrations in 2006 egg pools ranged from 4.5 to 20 ng/g wet weight (ww) and constituted 0.6-4.5% of sigma39PBDE concentrations among colonies, whereas sigma(octa)BDE and sigma(nona)BDE concentrations constituted from 0.5 to 2.2% and 0.3 to 1.1%, respectively. From 1982 to 2006, the BDE-209 doubling times ranged from 2.1 to 3.0 years, whereas for sigma(octa)BDEs and sigma(nona)BDEs, the mean doubling times ranged from 3.0 to 11 years and 2.4 to 5.3 years, respectively. The source of the octa- and nona-BDE congeners, e.g., BDE-207 and BDE-197, are the result of BDE-209 debromination, and they are either formed metabolically in Great Lakes herring gulls and/or bioaccumulated from the diet and subsequently transferred to their eggs. In contrast to BDE-209 and the octa- and nona-BDEs, congeners derived mainly from PentaBDE and OctaBDE mixtures, e.g., BDE-47, -99, and -100, showed rapid increases up until 2000; however, there was no increasing trend post-2000. The data illustrates that PBDE concentrations and congener pattern trends in the Great Lakes herring gull eggs have dramatically changed between 1995 and 2006. Regardless of BDE-209 not fitting the pervasive criteria as a persistent and bioaccumulative substance, it is clearly of increasing concern in Great Lake herring gulls, and provides evidence that regulation of DecaBDE formulations is warranted.

Current-use flame retardants in the eggs of herring gulls (Larus argentatus) from the Laurentian Great Lakes.

Of the 13, current-use, non-polybrominated diphenyl ether (PBDE) flame retardants (FRs) monitored, hexabromobenzene (HBB), pentabromoethylbenzene (PBEB), pentabromotoluene (PBT), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) and alpha- and gamma-isomers of hexabromocyclododecane (HBCD), and the syn- and anti-isomers of the chlorinated Dechlorane Plus (DP) were quantified in egg pools of herring gulls (Larus argentatus) collected in 2004 from six sites in all five of the Laurentian Great Lakes of North America. alpha-HBCD concentrations ranged from 2.1 to 20 ng/g (wet weight (ww)). Other "new" FR levels ranged from 0.004 to 1.4 ng/g ww and were much lower than those of the major BDE congeners that are in technical mixtures (namely BDE-47, -99, -100), where sigma3PBDE ranged from 186 to 498 ng/g ww. Nineteen hepta-BDEs (sigma(hepta) = 4.9-11 ng/g ww), octa-BDEs (alpha(octa) = 2.6-9.1 ng/g ww), and nona-BDEs (sigma(nona) = 0.12-5.6 ng/g ww) were detectible at all six colonies, while BDE-209 was low but quantifiable (< 0.1-0.21 ng/g ww) at two colonies. sigma-DP (syn- and anti-isomers) concentrations in eggs from all sites ranged from 1.5 to 4.5 ng/g ww. Our findings indicate that mother herring gulls are exposed to several, current-use flame retardants via their diet, and in ovo transfer occurred to their eggs. Given the aquatic diet of herring gull, this suggests that there are non-PBDE BFRs present in the gull-associated aquatic food web of the Great Lakes.

Brominated flame retardants in glaucous gulls from the Norwegian Arctic: more than just an issue of polybrominated diphenyl ethers.

Several, unregulated, current-use brominated flame retardants (BFRs), including hexabromobenzene (HBB), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), pentabromoethylbenzene (PBEB), pentabromotoluene (PBT), and hexabromocyclododecane (as total-(alpha)-HBCD), were examined in egg yolk and plasma of male and female glaucous gulls (Larus hyperboreus) from the Norwegian Arctic. Also examined were BDE209 and 38 tri- to nona-BDE congeners and brominated biphenyl (BB) 101. The HBB, BTBPE, PBEB, and PBT had high detection frequencies and variability in male and female plasma and egg yolk samples, and their concentrations ranged from nondetectable (< 0.02-0.27 ng/g wet wt) to 2.64 ng/g wet wt. The detection frequencies and range of concentrations of non-BDE BFRs were generally highest in plasma of males relative to females. Total-(alpha)-HBCD concentrations were highest among the non-PBDE BFRs (up to 6.12 and 63.9 ng/g wet wt in plasma and egg yolk, respectively). Next highest was HBB with concentrations within a range comparable to the minor PBDEs monitored (e.g., BDE28, 116 and 155). Sum (sigma)38PBDE concentrations ranged from 2.49 to 54.5 ng/g wet wt in plasma and 81.2 to 321 ng/g wet wt in egg yolk. The BDE209 was virtually nondetectable, whereas six octa-BDEs (i.e., BDE196, 197, 201, 202, 203, and 205), as well as three nona-BDEs (i.e., BDE206, 207, and 208, and potential BDE209 debromination products) were found sporadically in plasma and egg yolk. The results from this study suggestthat in addition to PBDEs, several current-use, non-BDE BFRs undergo long-range atmospheric transport and bioaccumulate at low levels in and are maternally transferred (to eggs) in glaucous gulls from the Norwegian Arctic.

Delta11 desaturases of Trichoplusia ni and Spodoptera littoralis exhibit dual catalytic behaviour.

The Delta(11) desaturases found in moths such as Spodoptera littoralis play a critical role in the biosynthesis of their sex pheromones. The ability to functionally express these enzymes in yeast has allowed one to study the transformation of long-chain fatty acyl substrates to their 11-ene products in greater mechanistic detail. In this article, we report on the detection and quantitation of a minor 11-hydroxylated byproduct (0.1% of total fatty acids), which is formed by the Delta(11) desaturases found in Trichoplusia ni and Spodoptera littoralis. The position of the hydroxyl group was determined by characteristic mass spectral fragmentation of the trimethylsilyl derivatives and is in accord with predictions based on previous mechanistic investigations of the Spodoptera Delta(11) desaturase. The level of 11-hydroxylation was insensitive to the mode of desaturase expression (constitutive vs. induced) and the presence or absence of a b5-fusion domain. Our findings suggest that in future, a search for hydroxylated products should be included in functional analyses of insect desaturase genes.

Quantitation of hydroxylated byproduct formation in a Saccharomyces cerevisiae Delta9 desaturating system.

The distribution of products obtained from stearoyl CoA Delta9 desaturase-mediated oxidation in Saccharomyces cerevisiae has been measured directly for the first time using an omega-fluorinated fatty acid substrate.