Non-polar halogenated natural products bioaccumulated in marine samples. II. Brominated and mixed halogenated compounds

Assessing Marine Endocrine-Disrupting Chemicals in the Critically Endangered California Condor: Implications for Reintroduction to Coastal Environments

Coastal reintroduction sites for California condors (Gymnogyps californianus) can lead to elevated halogenated organic compound (HOC) exposure and potential health impacts due to the consumption of scavenged marine mammals. Using nontargeted analysis based on comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/TOF-MS), we compared HOC profiles of plasma from inland and coastal scavenging California condors from the state of California (CA), and marine mammal blubber from CA and the Gulf of California off Baja California (BC), Mexico. We detected more HOCs in coastal condors (32 ± 5, mean number of HOCs ± SD, n = 7) than in inland condors (8 ± 1, n = 10) and in CA marine mammals (136 ± 87, n = 25) than in BC marine mammals (55 ± 46, n = 8). ∑DDT-related compounds, ∑PCBs, and total tris(chlorophenyl)methane (∑TCPM) were, respectively, ∼7, ∼3.5, and ∼148 times more abundant in CA than in BC marine mammals. The endocrine-disrupting potential of selected polychlorinated biphenyls (PCB) congeners, TCPM, and TCPMOH was determined by in vitro California condor estrogen receptor (ER) activation. The higher levels of HOCs in coastal condors compared to those in inland condors and lower levels of HOC contamination in Baja California marine mammals compared to those from the state of California are factors to consider in condor reintroduction efforts.

Defining Wound Healing Progression in Cetacean Skin: Characteristics of Full-Thickness Wound Healing in Fraser's Dolphins (Lagenodelphis hosei)

Simple Summary

Cutaneous wound healing is a complex and tightly regulated biological process to restore physiological and anatomic function. Current knowledge of cutaneous wound healing is mostly based on studies in laboratory animals and humans. The histological and immunological features of skin, for example, cutaneous thickness, cellular components, and immune response, are not identical among animal species, and these differences may lead to substantial effects in cutaneous wound healing. In field observation, large cutaneous wounds in cetaceans could heal without medical treatments. However, little is known about the underlying mechanisms, and there is no histological study on full-thickness wound healing in cetaceans. The current study characterizes the macroscopic and histological features of large full-thickness wound healing in Fraser’s dolphins (Lagenodelphis hosei). The differences of wound healing between cetaceans and terrestrial mammals were shown from the histological aspect, including rete and dermal ridge appearance, repigmentation, and adipose tissue regeneration. Better understanding of the mechanism of full-thickness wound healing in cetaceans will shed light on veterinary and human regenerative medicine, leading to novel therapies.

Abstract

Cetaceans are tight-skinned mammals that exhibit an extraordinary capacity to heal deep soft tissue injuries. However, essential information of large full-thickness wound healing in cetaceans is still lacking. Here, the stages of full-thickness wound healing were characterized in Fraser’s dolphins (Lagenodelphis hosei). The skin samples were collected from normal skin and full-thickness cookiecutter shark (Isistius brasiliensis)-bite wounds of stranded carcasses. We defined five stages of wound healing according to macroscopic and histopathological examinations. Wounds in Stage 1 and 2 were characterized by intercellular and intracellular edema in the epidermal cells near the wound edge, mixed inflammatory cell infiltration, and degradation of collagen fibers. In Stage 3 wounds, melanocytes, melanin granules, rete and dermal ridges were noticed in the neo-epidermis, and the adipose tissue in adjacent blubber was replaced by cells and fibers. Wounds in Stage 4 and 5 were characterized by gradual restoration of the normal skin architecture including rete and dermal ridges, collagen bundles, and adipose tissue. These phenomena were quite different from previous studies in terrestrial tight-skinned mammals, and therefore, further in-depth research into the mechanisms of dolphin wound healing would be needed to gain new insights into veterinary and human regenerative medicine.

Occurrence and concentrations of halogenated natural products derived from seven years of passive water sampling (2007-2013) at Normanby Island, Great Barrier Reef, Australia

Polydimethylsiloxane (PDMS) based passive water samplers deployed at Normanby Island, Great Barrier Reef (Australia) from 2007 to 2013 were analyzed for halogenated natural products (HNPs). Altogether, 38 samples, typically deployed for 30 days, were studied. Five HNPs (Q1, 2'‑MeO-BDE 68, BC-10, 2,4‑dibromoanisole and 2,4,6‑tribromoanisole) were detected in all samples. Most samples (>90%) featured 2,2'‑diMeO-BB 80, 6‑MeO-BDE 47, 2',6‑diMeO-BDE 68 and 2,4‑dibromophenol. In addition, tetrabromo‑N‑methylpyrrole (TBMP) was detected in ~80% and Cl₆-DBP in ~30% of the samples. Estimated time weighted maximum water concentrations were >150 pg Q1 and 60 pg 2'‑MeO-BDE 68 per L seawater. Typically, the concentrations were varying from year to year. Moreover, time weighted average water concentration estimates did not reveal consistent maximum trend levels within a given year. Additional screening analysis via GC/MS indicated the presence of several polyhalogenated 1'‑methyl‑1,2'‑bipyrroles (PMBPs), 1,1'‑dimethyl‑2,2'‑bipyrroles (PDBPs), and 1‑methylpyrroles (PMPs) along with four brominated N‑methylindoles and several other polyhalogenated compounds at Normanby Island.

Occurrence of halogenated natural products in highly consumed fish from polluted and unpolluted tropical bays in SE Brazil

Natural compounds from the metabolism of marine organisms have been detected at high concentrations in environmental samples which are not the producers of these compounds. These natural substances are known as halogenated natural products (HNPs). HNPs are possibly toxic halogenated compounds analogous to POPs that may bioaccumulate and biomagnify along the food web and pose a further risk to human and environmental health. The present study analyzed the occurrence of HNPs in the edible muscle of the three most consumed commercial fish species in the state of Rio de Janeiro: sardine (Sardinella brasiliensis), whitemouth croaker (Micropogonias furnieri) and mullet (Mugil liza) from the highly polluted Guanabara Bay (GB) and the less polluted Ilha Grande Bay (IGB). The analytical steps included Soxhlet extraction, clean-up step and injection in a gas chromatography system coupled to a mass spectrometer operated in the electron-capture negative ion mode (GC/ECNI-MS). The compounds 2,4,6-TBP, 2,4,6-TBA, MHC-1, Q1, 6-MeO-BDE 47 and 2'-MeO-BDE 68 were found in the analyzed fish from both studied areas. Q1, 6-MeO-BDE 47 and 2'-MeO-BDE 68 showed the highest concentrations in samples. Q1 concentrations in the sardines from IGB were higher than the sardines from GB (p < 0.05) and higher than the other IGB species (p < 0.05). The differences found among the species may be related to their characteristic habitat and diet. It is noteworthy that most of these compounds do not have any toxicological reference value. Moreover, the HNPs are being detected in species of low trophic level and since this study has worked only with commercial species, these fish may be considered as a source for human exposure to these natural compounds.

Halogenated flame retardants in stranded sperm whales (Physeter macrocephalus) from the Mediterranean Sea

In recent years, decline of marine mammals' populations and increased frequency of strandings have arised the interest on the role that pollution may have in these events. The present work aimed at quantifying levels of brominated flame retardants (BFRs) and dechloranes (DECs) in tissues of 3 adult females and one foetus of sperm whales stranded in the Southern Adriatic Sea coasts (Italy). Results proved the presence of different flame retardants (FRs) in tissues of sperm whales, including various polybrominated diphenyl ethers (PBDE) congeners (47, 99, 100, 154, entering the composition of PentaBDE mixture), hexabromocyclodecanes (HBCDs), Dec 602 and methoxylated polibrominated diphenyl ethers (MeO-BDEs). In blubber, a target tissue for contaminant accumulation, ΣPBDEs reached values of 160, 158 and 183 ng/g lw, α-HBCD of 5.75 ng/g lw, Dec 602 of 1632 ng/g lw and MeO-BDEs of 563 ng/g lw. The availability of foetal tissues allowed evaluating the potential maternal transfer on many of these compounds, and to discuss the potential adverse effects on foetal health. To the best of our knowledge, obtained data are the first reporting placental transfer of FRs in sperm whales. PBDE levels detected in foetus suggested a potentially long-term exposure to BFRs, which could cause severe damages to the developing organism, likely at the cerebral, endocrine and immunologic levels. Dec 602, which was detected at the highest concentrations among all FRs considered, could potentially cause dysfunctional effects on the immune system of adult females.

Synthesis, structure elucidation, and determination of polyhalogenated N-methylpyrroles (PMPs) in blue mussels

Polyhalogenated N-methylpyrroles (PMPs) are halogenated natural products (HNPs) recently detected in seagrass, blue mussels, and other marine organisms. In this study, we synthesized 2,3,4,5-tetrachloro-N-methylpyrrole (Cl₄-MP), 2,3,4,5-tetrabrominated-N-methylpyrrole (Br₄-MP, aka TBMP), and mixed tetrahalogenated (Cl and Br) N-methylpyrrole congeners. Use of one- and two-dimensional ¹H and ¹³C NMR verified the structures of isolated/enriched 3,4-dibromo-2,5-dichloro-N-methylpyrrole (3,4-Br₂-2,5-Cl₂-MP), 2,3,4-tribromo-5-chloro-N-methylpyrrole (2,3,4-Br₃-5-Cl-MP), and 3-bromo-2,4,5-trichloro-N-methylpyrrole (3-Br-2,4,5-Cl₃-MP). GC/EI-MS and GC/ECNI-MS mass spectra of the five PMPs were studied with regard to fragmentation pattern and individual responses which were strongly affected by the presence (or absence) of Br in α-position(s). Quantitative solutions of the synthesized standards were used to determine the elution order of isomers and to quantify PMPs in selected blue mussel samples (Mytilus sp.) from the European Atlantic coast (Spain, France), the North Sea (the Netherlands, Germany) and Baltic Sea (Germany). PMPs were detected in all samples and the concentrations ranged between 0.6 and 52 μg/kg lipids with Br₄-MP being the most abundant representative of this substance class.

Polybrominated diphenyl ethers (PBDEs) and their hydroxylated and methoxylated analogues in the blood of harbor, Dall's and finless porpoises from the Japanese coastal waters

This study investigated the accumulation of polybrominated diphenyl ethers (PBDEs) and their hydroxylated and methoxylated analogues (OH-PBDEs and MeO-PBDEs) in the blood of harbor porpoises, Dall's porpoises, and finless porpoises stranded or bycaught in Japanese coastal waters and in the North Pacific Ocean. Moreover, we suggested the origins of these contaminants and the factors affecting their pattern of accumulation. Levels of PBDEs in Dall's porpoises were one order of magnitude greater than those in the other species. OH-PBDE and MeO-PBDE levels were comparable to those of PBDEs. However, no correlation was found between the levels of OH-PBDEs and PBDEs, whereas a strong correlation was found between that of OH-PBDEs and MeO-PBDEs (p < 0.001). 6OH-BDE47, reported compound biosynthesized by marine low-trophic level organisms, was the dominant congener. These results suggest that PBDEs found in these porpoise species derive from flame retardants, but OH-PBDEs and MeO-PBDEs are mainly of natural origins.

Levels, profiles and dietary sources of hydroxylated PCBs and hydroxylated and methoxylated PBDEs in Japanese women serum samples

Human exposure to polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) may result in retention of specific congeners of hydroxylated PCBs (OH-PCBs) and hydroxylated/methoxylated PBDEs (OH-/MeO-PBDEs) in serum. However, dietary sources and biotransformation of OH-/MeO-PBDEs in humans are poorly understood. Therefore, this study was conducted to investigate the levels, profiles, and exposure sources of OH-/MeO-PBDEs along with OH-PCBs present in human serum. Twenty serum samples pooled from women of four age groups (30s/40s/50s/60s) living in four districts of Japan were analyzed for OH-/MeO-PBDEs, and their profiles were then compared with those of seafood (seaweed and fish). The major component of OH-PCBs in the phenolic fraction of serum was 4-OH-CB187 (mean: 85pgg^-1 wet weight (ww)). Total OH-PCBs accounted for about 1/20 of the total PCBs (mean; 1800pgg^-1 ww). In contrast, the predominant component of OH-PBDEs in serum was 6-OH-BDE47 (mean: 183pgg^-1 ww), which was about 20-fold higher than BDE-47 (mean; 8.7pgg^-1 ww). In the neutral fraction, 2'-MeO-BDE68 was primarily found at a similar concentration (mean 5.6pgg^-1 ww) to BDE-47. Both 4-OH-PCB187 and 2'-MeO-BDE68 were significantly correlated with woman's age (p<0.01), but not with 6-OH-BDE47 or BDE-47. The profiles of OH-PBDEs in serum were consistent with those in edible seaweeds (Sargassum fusiforme) sold for human consumption, whereas MeO-PBDEs had a similar profile as those in edible fish (Serranidae sp.) from Japanese coastal waters. These findings indicate that the profiles of OH-PBDEs and MeO-PBDEs in Japanese serum are different from those in other countries, and their sources may be specific edible seaweeds and fish, respectively. This is the first report of profiles and dietary sources of OH/MeO-PBDEs in human serum from Japan.

Characterization of Three Tetrabromobisphenol-S Derivatives in Mollusks from Chinese Bohai Sea: A Strategy for Novel Brominated Contaminants Identification

Identification of novel brominated contaminants in the environment, especially the derivatives and byproducts of brominated flame retardants (BFRs), has become a wide concern because of their adverse effects on human health. Herein, we qualitatively and quantitatively identified three byproducts of tetrabromobisphenol-S bis(2,3-dibromopropyl ether) (TBBPS-BDBPE), including TBBPS mono(allyl ether) (TBBPS-MAE), TBBPS mono(2-bromoallyl ether) (TBBPS-MBAE) and TBBPS mono(2,3-dibromopropyl ether) (TBBPS-MDBPE) as novel brominated contaminants. Meanwhile, the mass spectra and analytical method for determination of TBBPS-BDBPE byproducts were presented for the first time. The detectable concentrations (dry weight) of TBBPS-MAE, TBBPS-MBAE and TBBPS-MDBPE were in the ranges 28-394 μg/g in technical TBBPS-BDBPE and 0.1-4.1 ng/g in mollusks collected from the Chinese Bohai Sea. The detection frequencies in mollusk samples were 5%, 39%, 95% for TBBPS-MAE, TBBPS-MBAE and TBBPS-MDBPE, respectively, indicating their prevailing in the environment. The results showed that they could be co-produced and leaked into the environment with production process, and might be more bioaccumulative and toxic than TBBPS-BDBPE. Therefore, the production and use of TBBPS derivatives lead to unexpected contamination to the surrounding environment. This study also provided an effective approach for identification of novel contaminants in the environment with synthesized standards and Orbitrap high resolution mass spectrometry.

Polybrominated diphenyl ethers and their methoxylated and hydroxylated analogs in Brown Bullhead (Ameiurus nebulosus) plasma from Lake Ontario

Polybrominated diphenyl ethers (PBDEs), methoxylated PBDEs (MeO-PBDEs) and hydroxylated PBDEs (OH-PBDEs) were detected and quantified in Brown Bullhead (Ameiurus nebulosus) from Lake Ontario. Samples were collected in 2006 from three different locations near the city of Toronto: Frenchman's Bay, Toronto Island, and Tommy Thompson Park. A total of 117 plasma samples were pooled into 19 samples, separating males and females by site of capture. Pooled samples were analyzed for 36 PBDEs, 20 MeO-PBDEs and 20 OH-PBDEs, but only six PBDEs, five MeO- and eight OH-compounds were confirmed against standards currently available. These peaks were quantified as "identified" peaks, while peaks matching ion ratios but not matching the retention time of the available standards were quantified as "unidentified" peaks. Both "identified" and "unidentified" concentrations were combined to obtain a total concentration. No significant variations were obtained for total PBDE concentrations, ranging from 3.33 to 9.02 ng g(-1)wet weight. However, OH- and MeO-PBDE totals ranged over 1 order of magnitude among the samples (not detected - 3.57 ng g(-1)wet weight for OH-PBDEs and not detected -0.10 ng/g wet weight for MeO-PBDE). The results of this study suggested that these compounds are ubiquitous in biota. Source estimation of MeO- and OH-PBDEs in freshwater fish were discussed. Considering that up to date no freshwater sources for MeO- or OH-PBDEs have been reported, concentrations found should be mainly related to bioaccumulation from anthropogenic sources, although other sources could not be dismissed.

Hydrodebromination of decabromodiphenyl ether (BDE-209) in cooking experiments with salmon fillet

Polybrominated diphenyl ethers (PBDEs) are environmental contaminants regularly detected in biota and food. Seafood has been identified as the major dietary source for human uptake. Fish is predominantly consumed after cooking, and this process may alter the actual human intake of contaminants. This study thus aimed to investigate the fate of PBDEs in this cooking process. Heating of fish fortified with 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE-209) at typical cooking conditions (200 °C, in plant oil) resulted in a decrease of its concentration in favor of the formation of lower brominated congeners. After 15 min, ∼25% of BDE-209 was transformed into nona- to octabrominated congeners. The major transformation route was BDE-209 → BDE-206 → BDE-196 and BDE-199. Low amounts of heptabrominated congeners as well as one hexabromodibenzofuran and a heptabromodibenzofuran isomer were also detected. However, penta- and tetrabrominated diphenyl ethers were not observed, and heating of BDE-47 did not produce new transformation products.

Thorough analysis of polyhalogenated compounds in ray liver samples off the coast of Rio de Janeiro, Brazil

INTRODUCTION

Five liver samples of two different ray species (Gymnura altavela and Zapteryx brevirostris) off the coast of Rio de Janeiro, Brazil, were analyzed for their pollution with anthropogenic and naturally occurring organohalogen compounds.

MATERIAL AND METHODS

The samples were extracted with accelerated solvent extraction, and after a clean-up procedure, organohalogen compounds were separated by a modified group separation on activated silica. Subsequent analyses were done by targeted and non-targeted gas chromatography-mass spectrometry in the electron capture negative ion mode.

RESULTS AND DISCUSSION

"Classic" organohalogen compounds such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and technical 1,1,1-trichloro-2,2-di(4-chlorophenyl)ethane (DDT) were detected and quantified. PCBs generally exceeded the parts per million level and represented up to 90% of the total contamination of the ray livers. High concentrations were also detected for p,p'-DDE. Non-targeted full scan investigations lead to the detection of an abundant trichlorinated compound which was identified as a new DDT metabolite in biota. Different PBDE congeners and several halogenated natural products were quantified as well. In addition, polychlorinated terphenyls were identified and analyzed in the two species. Moreover, both ray species showed different fatty acid patterns and stable carbon isotope signatures.

CONCLUSIONS

The two ray species showed high concentrations of organohalogen compounds in their liver tissue. Varied δ (13)C values by up to 3.1‰ indicated that the two ray species were living in different habitats.

Identification of the natural product 2,3,4,5-tetrabromo-1-methylpyrrole in Pacific biota, passive samplers and seagrass from Queensland, Australia

Halogenated natural products (HNPs) are frequently detected in marine organisms. High HNP concentrations have previously been found in marine mammals from the Great Barrier Reef, Australia, including in the blubber of herbivorous dugongs (Dugong dugon). To identify the source of HNPs we initially focused on the analysis of Australian seagrass (Halophila ovalis) which serves as the principal food source for dugongs. GC/MS analysis of the seagrass indicated the presence of several organobromine compounds. One compound was identified as 2,3,4,5-tetrabromo-1-methylpyrrole (TBMP) by synthesis. Subsequent analysis of semipermeable membrane devices demonstrated that the photo-sensitive TBMP is widespread in the Great Barrier Reef (Queensland, Australia). The detection of larger TBMP concentrations in fish fillets from Chile and traces in mussels from New Zealand indicated that this potential HNP may be distributed throughout the Southern Pacific Ocean.

Sorption-desorption behavior of polybrominated diphenyl ethers in soils

Polybrominated diphenyl ethers (PBDEs) are flame retardants that are commonly found in commercial and household products. These compounds are considered persistent organic pollutants. In this study, we used 4,4'-dibromodiphenyl ether (BDE-15) as a model compound to elucidate the sorption and desorption behavior of PBDEs in soils. The organic carbon-normalized sorption coefficient (K(OC)) of BDE-15 was more than three times higher for humin than for bulk soils. However, pronounced desorption hysteresis was obtained mainly for bulk soils. For humin, increasing concentration of sorbed BDE-15 resulted in decreased desorption. Our data illustrate that BDE-15 and probably other PBDEs exhibit high sorption affinity to soils. Moreover, sorption is irreversible and thus PBDEs can potentially accumulate in the topsoil layer. We also suggest that although humin is probably a major sorbent for PBDEs in soils, other humic materials are also responsible for their sequestration.

Stable carbon isotope analysis (δ13C values) of polybrominated diphenyl ethers and their UV-transformation products

Polybrominated diphenyl ethers (PBDEs) are frequently detected in food and environmental samples. We used compound specific isotope analysis to determine the δ(13)C values of individual PBDEs in two technical mixtures. Within the same technical product (DE-71 or DE-79), BDE congeners were the more depleted in (13)C the higher brominated they were. In contrast, the products of light-induced hydrodebromination of BDE 47 and technical DE-79 were more enriched in (13)C because of more stable bonds between (13)C and bromine. As a result, the δ(13)C values of the irradiated solution progressed diametrically compared to those of the technical synthesis. The ratio of the δ(13)C values of BDE 47 to BDE 99 and of BDE 99 to BDE 153 are thus suggested as indicators to distinguish native technical products from transformation products. Ratios <1 are typical for native congeners (e.g. in DE-71) while the reversed ratio (>1) is typical of transformation products.

Bromination of 2-methoxydiphenyl ether to an average of tetrabrominated 2-methoxydiphenyl ethers

Brominated 2-phenoxyanisoles (2-methoxydiphenyl ethers, 2-MeO-BDEs) are a class of halogenated natural products, produced by algae and sponges. Especially two tetrabrominated isomers, i.e. 2'-MeO-BDE 68 (BC-2) and 6-MeO-BDE 47 (BC-3), have also been frequently determined in environmental and food samples. In addition, 2-MeO-BDEs are under discussion as metabolites of polybrominated diphenyl ethers (PBDEs). In this study, we synthesized the backbone 2-methoxydiphenyl ether and brominated it to an average degree of four bromine substituents. The reaction mixture only contained one major product (∼90%) along with three further MeO-BDEs and ∼5% hydroxylated BDEs. In all likelihood, the HO-BDEs were formed in a side reaction by cleavage of the methoxy group. The major MeO-BDE was identified as 6'-methoxy-2,3',4,4'-tetrabromodiphenyl ether (6'-MeO-BDE-66). The HO-BDEs were separated by KOH/n-hexane partitioning, and the resulting 2-MeO-BDEs were fractionated by means of high-speed counter-current chromatography (HSCCC). Due to the excellent enrichment facilities of HSCCC, some 15 MeO-BDEs, mainly present at traces only, could be detected in 26 fractions, and eight of them could be characterized by nuclear magnetic resonance spectroscopy (NMR). Only two of the compounds--2'-MeO-BDE 68 and 6-MeO-BDE 123--had been characterized as natural products while the prominent halogenated natural product 6-MeO-BDE 47 was not detected at all in the reaction product. The "non-natural" 2-MeO-BDEs may be useful internal standards in trace analysis.

Marine natural products, the halogenated 1'-methyl-1,2'-bipyrroles, biomagnify in a northwestern Atlantic food web

Halogenated 1'-methyl-1,2'-bipyrroles (MBPs) are putative marine natural products that accumulate in marine mammal blubber in similar concentrations and patterns to biomagnifying organic pollutants. Here we measure concentrations of MBPs and 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) in 40 samples composed of eight fish species, two squid species, and six species of marine mammals. To determine their trophic positions and to further investigate influence of prey preference, we also measured the stable carbon and nitrogen isotopic compositions of all samples. Our results show that lipid-normalized MBP concentrations increase with increasing trophic level; therefore, MBPs qualify as another class of biomagnifying marine natural products. The presence of MBPs in pinniped prey and absence in pinniped blubber suggests that these mammals share dietary exposure to MBPs with odontocetes but have an enhanced ability to metabolize these natural products.

Gas chromatography coupled to electron capture negative ion mass spectrometry with nitrogen as the reagent gas--an alternative method for the determination of polybrominated compounds

Gas chromatography in combination with electron capture negative ion mass spectrometry (GC/ECNI-MS) is a sensitive method for the determination of polybrominated compounds in environmental and food samples via detection of the bromide ion isotopes m/z 79 and 81. The standard reagent gas for inducing chemical ionization in GC/ECNI-MS is methane. However, the use of methane has some drawbacks as it promotes carbonization of the filament and ion source. In this study, we explored the suitability of nitrogen as reagent gas for the determination of brominated flame retardants (polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), allyl-2,4,6-tribromophenyl ether (ATE) and 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE)) and halogenated natural products (for instance, methoxylated tetrabrominated diphenylethers and polybrominated hexahydroxanthene derivatives). An ion source temperature of 250 degrees C and a nitrogen pressure of 7 Torr in the ion source gave the highest response for m/z 79 and 81 of virtually all investigated polybrominated compounds. Using these conditions, nitrogen-mediated GC/ECNI-MS usually gave higher sensitivity than the method with methane previously used in our lab. In addition, the ion source was not contaminated to the same degree and the lifetime of the filament was significantly increased. Moreover, the response factors of the different polybrominated compounds with the exception of 2,4,6-tribromophenol were more uniform than with methane. Nitrogen is available at very high purity at relatively low price.

Negative APCI-LC/MS/MS method for determination of natural persistent halogenated products in marine biota

A sensitive and selective method utilizing high performance liquid chromatography coupled to negative atmospheric pressure chemical ionization tandem mass spectrometry (APCI-LC/MS/MS) was developed to enable analysis of selected natural persistent organohalogens accumulated in marine biota. The analytes were three methoxylated tetrabromodiphenyl ethers (6-MeO-BDE47, 2'-MeO-BDE68, and 2',6-diMeO-BDE68), a dimethoxylated tetrabromobiphenyl (2,2'-diMeO-BB80), and two halogenated methyl bipyrroles (Cl(7)-MBP and Br(4)Cl(2)-DBP). These products were well resolved on a 150 mm reversed-phase column with methanol as the mobile phase. The fragmentation pathways of the Cl(7)-MBP and Br(4)Cl(2)-DBP produced characteristic multiple reaction monitoring (MRM) transitions. Determination was performed in the MRM mode using phenoxide ion [M-Br+O](-) and product Br(-) ions for MeO-BDE analogues, or the precursor [M-Cl+O](-) to Br(-) ion for Br(4)Cl(2)-DBP, and to C(4)NCl(4)(-) ion for Cl(7)-MBP. The APCI-LC/MS/MS method is acceptable for calibration of the linearity and repeatability of all products studied in the low ng/g (lipid weight) level and with similar sensitivity to the electron ionization (EI)-GC/MS method. The proposed method was applied for quantification of natural organohalogens accumulated in melon-headed whale (Peponocephala electra) blubber (N = 15) in the Asia-Pacific Ocean. The concentration was positively correlated between different groups of compounds except for 2'-MeO-BDE68. The use of the analytical method based on negative ion APCI-LC/MS/MS would provide a new way for rapid monitoring of halogenated natural products from marine biota, such as sponges or algae.

Determination of halogenated natural products in passive samplers deployed along the Great Barrier Reef, Queensland/Australia

Halogenated natural products (HNPs) have been increasingly reported to occur in marine wild life from all oceans. Several HNPs, such as 2,3,3',4,4',5,5'-heptachloro-1'-methyl-1,2'-bipyrrole (1) and 4,6-dibromo-2-(2',4'-dibromo)phenoxyanisole (2'-MeO-BDE 68 or BC-2), were detected at particularly high concentrations in dolphins from Queensland/Australia. About half of the coastline of Queensland (approximately 2500 km) is covered by the Great Barrier Reef, a rich ecosystem hosting a huge variety of species, many of which are known to produce natural compounds. In this study, semipermeable membrane devices (SPMDs) were deployed as passive samplers for about 30 days at 12 marine and 2 nonmarine sites (i.e., rivers) along the Great Barrier Reef as part of a routine monitoring program during November 2007 and May 2008. Q1 and 2'-MeO-BDE 68 were detected at the marine sites with frequencies of about 65% but not in any sample from the two rivers. Further HNPs (2,4,6-tribromophenol, TBP; 2,4,6-tribromoanisole, TBA; 2,2'-dimethoxy-3,3'5,5'-tetrabromobiphenyl, 2,2'-diMeO-BB 80 or BC-1; 3,5-dibromo-2-(2',4'-dibromo)phenoxyanisole, 6-MeO-BDE 47 or BC-3; and 3,5-dibromo-2-(3',5'-dibromo,2'-methoxy)phenoxyanisole, 2',6-diMeO-BDE 68 or BC-11) were detected as well with frequencies of 18-97% in the marine samples, but no polybrominated flame retardants were detected. The highest amount of a single HNP, 2.3 microg/SPMD, was determined for TBP, which had a frequency of detection of only 46%. The maximum (average) amount in the SPMDs from marine sites was 44 ng (12 ng) for (1 and 115 ng (20 ng) for 2'-MeO-BDE 68. A first order kinetic model was used to estimate concentrations of the HNPs in the water phase. Based on the depuration of performance reference compounds obtained at one of the sites, we assumed a sampling rate of 16 L/day. We used this sampling rate to estimate that the highest and average available concentrations of Q1 in the water during the deployment of the SPMD were 97 and 25 pg/L, respectively. The estimated maximum water concentrations of 2'-MeO-BDE 68, 2,2'-diMeO-BB 80, 6-MeO-BDE 47, and 2',6-diMeO-BDE 68 were on average 2-5.5 fold higher than that of Q1. The results confirm that the HNPs are produced throughout the Great Barrier Reef, which appears to be a significant source of these compounds.

Accumulation and mother-to-calf transfer of anthropogenic and natural organohalogens in killer whales (Orcinus orca) stranded on the Pacific coast of Japan

Blubber samples were analyzed for anthropogenic and natural persistent organohalogens in nine killer whales (Orcinus orca) stranded on the northern coast of Japan in 2005. Anthropogenic organohalogens were dominated by DDTs (40-240 microg/g lipid weight (lw)), PCBs (19-68 microg/g lw), and chlordanes (trans-nonachlor, 15-80 microg/g lw). Polybrominated diphenyl ethers (PBDEs) were detected at a range of 0.22-0.64 microg/g lw (BDE-47, 42-74% of SigmaPBDE). For natural organohalogens, mixed halogenated dimethylbipyrroles (Br4Cl2-DBP, 6.4-26 microg/g lw), heptachlorinated methylbipyrrole (Cl7-MBP, 0.5-1.9 microg/g lw), two methoxylated tetrabromodiphenyl ethers (6-MeO-BDE47, 0.11-0.58 microg/g lw; 2'-MeO-BDE68, 0.02-0.06 microg/g lw), and dimethoxylated tetrabromobiphenyl (2,2'-diMeO-BB80, 0.06-0.20 microg/g lw) were present. These concentrations in the blubber were higher in calves than in lactating females, indicating that large quantities of the persistent organohalogens transferred from the mother to the calf through lactation. The mother-to-calf transfer ratios of PCBs and PBDEs were significantly decreased with increasing number of halogen substituents, suggesting that higher halogenated congeners are less transferable.

Occurrence and congener specific profiles of polybrominated diphenyl ethers and their hydroxylated and methoxylated derivatives in breast milk from Catalonia

The presence of polybrominated diphenyl ethers (PBDEs) from mono to hepta brominated and 11 hydroxylated (OH-) and methoxylated (MeO-) PBDEs was examined in 37 breast milk samples collected from 11 mothers living in Barcelona. An extraction method based on accelerated solvent extraction followed by gas chromatography coupled to high resolution mass spectrometry was used to inequivocally identify all target compounds at the low pg g(-1) lw level. Data obtained were examined for absolute and relative concentrations and specific PBDE, OH- and MeO-PBDE congener patterns. Sigma PBDE concentration ranged between 1,161 and 1,372,797 pg g(-1) lw and BDEs 47, 99, 100, 153 and 183 accounted for more than 80% of the total PBDEs. All tri and tetra OH- and MeO-PBDEs compounds were detected at levels between 6 and 14,984 pg g(-1)lw. The median ratio OH/PBDE and MeO-PBDEs/PBDEs was from 2.9% to 1.6%, respectively, suggesting either that PBDE metabolism to OH- and MeO- derivatives is not an important degradation route in humans or either OH- and MeO-PBDEs are rapidly excreted. No significant correlation was observed between PBDEs and OH- and MeO-PBDE, although OH- and OMe-PBDEs co-occurred in mothers' milk (R(2)=0.5349). According to the daily intake of PBDEs and OH- and MeO-PBDEs, which was between 0.47 and 363 ng d(-1) (excluding a smoking donor), potential health risks associated with these compounds are assessed.

Detailed analysis of polybrominated biphenyl congeners in bird eggs from Norway

Individual eggs of six species of birds from Norway representing different food chains were analysed for residues of polybrominated biphenyls (PBBs). In all species, the residue pattern was dominated by hexaBBs. The dominating congeners were PBB 153, PBB 154, and PBB 155. Whereas PBB 153 is present in technical hexabromobiphenyl, PBB 154 and PBB 155 are formed by the reductive debromination of decabromobiphenyl. This was evidenced by the detection of several heptaBBs and octaBBs all of which are typical degradation intermediates of PBB 209. Hepta- and octaBBs were more than one order of magnitude less abundant than the hexaBBs. The second most prevailing homologue group was pentaBBs. The most relevant pentabrominated isomers were PBB 99 and PBB 101. Concentrations of the three hexaBBs--PBB 153, PBB 154, and PBB 155--amounted to 1.3-13 ng/g wet weight or 3-23% of the contamination with polybrominated diphenyl ethers.

Identification and quantification of new polybrominated dimethoxybiphenyls (PBDMBs) in marine mammals from Australia

Marine mammals from Queensland, Australia, are bioaccumulating elevated concentrations of a range of polybrominated natural products. In this study, we detected three new polybrominated dimethoxybiphenyls (PBDMBs) in the blubber of selected marine mammal samples which were identified as 2,6'-dimethoxy-3,3',5-tribromobiphenyl (2,6'-diMeO-BB 36), 2,2'-dimethoxy-3,3'-dibromobiphenyl (2,2'-diMeO-BB 36), and 6,6'-dimethoxy-3,3'-dibromobiphenyl (6,6'-diMeO-BB 11). These three PBDMBs are structurally related to the known natural product 2,2'-dimethoxy-3,3',5,5'-tetrabromobiphenyl (2,2'-diMeO-BB 80). In the first part of this study, 2,2'-diMeO-BB 80 was photochemically debrominated under UV irradiation. This resulted in seven of eight possible mono- to triBDMBs as debromination products. In the second part of this study, the structure of all PBDMBs debromination products was investigated. This was supported by synthesis of two diBDMB and one triBDMB via bromination and subsequent methylation of 2,2'-biphenyldiol. Structures of the remaining PBDMBs were tentatively assigned by considering the retention times, mass spectra and amounts formed during UV irradiation of 2,2'-diMeO-BB 80 . In the third part of this study, blubber of marine mammals from Australia was analysed for PBDMBs using gas chromatography in combination with electron ionization mass spectrometry (GC/EI-MS) in the selected ion monitoring mode. In these samples, 2,2'-diMeO-BB 80 was found at concentrations of 200-1800ngg(-1) lipid weight (lw). The latter represents the highest concentration reported for this compound in environmental samples. 6,6'-diMeO BB 11, 2,2'-diMeO BB 36, and 2,6'-diMeO BB 36 were present at approximately 7ngg(-1) lipids, or 0.43-1.5% of diMeO-BB 80. No further PBDMBs were detected in the samples. The di- and triBDMBs identified in marine mammal blubber have not been reported as natural products. They may represent either new natural products or transformation products of 2,2'-diMeO-BB 80.

Structure and origin of the natural halogenated monoterpene MHC-1 and its concentrations in marine mammals and fish

The halogenated natural product previously named mixed-halogenated compound 1 (MHC-1) was isolated from the red seaweed Plocamium cartilagineum harvested in Helgoland, Germany. A total of 1.9 mg of pure MHC-1 was obtained from 1g air-dried seaweed. The 1H and 13C NMR data matched those reported for a natural monoterpene isolated from this species. Thus, the structure of MHC-1 was established to be (1R,2S,4R,5R,1'E)-2-bromo-1-bromomethyl-1,4-dichloro-5-(2'-chloroethenyl)-5-methylcyclohexane. Moreover, the isolated monoterpene proved to be identical with the compound previously detected in marine mammals and fish from different locations. In addition we examined two samples of P. cartilagineum from Ireland and from the Antarctic; however MHC-1 was only present at low levels. Not only the concentrations were lower but also the pattern of polybrominated compounds differed from MHC-1. A calibrated solution of MHC-1 was used to determine correct concentrations from samples where previously only estimates existed relative to the gas chromatography-electron capture detector (GC/ECD) response of trans-chlordane, which underrated the MHC-1 concentrations by more than factor 2. The highest MHC-1 concentration determined to date in marine mammals is 0.14 mg kg(-1) blubber. Significantly higher MHC-1 concentrations were determined in farmed fish with up to 2.2 mg kg(-1) lipids. The samples with high concentrations of MHC-1 have in common that they were collected in proximity of the natural habitats of P. cartilagineum.

Gas chromatography retention data of environmentally relevant polybrominated compounds

Polybrominated organic compounds are ubiquitous throughout the environment. This generic term comprises several classes of brominated flame retardants (e.g., polybrominated diphenyl ethers, polybrominated biphenyls, hexabromocyclododecane, dibromopropyltribromophenyl ether, 1,2-bis(2,4,6-tribromophenoxy)ethane) as well as a range of marine halogenated natural products (HNPs). Here we present gas chromatography retention times and elution orders (on DB-5) of 122 polybrominated compounds that may be found in food and environmental samples. Organobromine compounds in fish samples determined with gas chromatography interfaced to electron-capture negative ion mass spectrometry (GC/ECNI-MS) are discussed. The environmental relevance and important mass spectrometric features of the compounds are described as well. Our database aims to support the closer inspection and identification of peaks in gas chromatograms and to initiate dedicated screening for less frequently studied organobromines in samples.

Anaerobic transformation of polybrominated biphenyls with the goal of identifying unknown hexabromobiphenyls in Baltic cod liver

Polybrominated biphenyls (PBBs) have been introduced as flame retardants in 1970. Despite decreasing application rates since the mid-1970s, PBB residues are still reported in the environment. Furthermore, environmental PBB residues often do not match the PBB pattern in technical products. To get insights into the structures of environmentally-relevant PBBs, the congener patterns of technical hexabromobiphenyl (THBB), octabromobiphenyl (TOBB), synthesized PBB 209 were compared to PBB residues in a cod liver sample from the Baltic Sea. The most relevant PBB congeners in Baltic cod liver were not present in the technical products and therefore most likely metabolites. For this reason, TOBB and HPLC-fractions obtained from this technical product were incubated with super-reduced cyanocobalamine. Reductive debromination was found to be the predominant transformation process. Bromine substituents in ortho-positions proved to be more recalcitrant, and several of the unknown PBBs were tri- and tetra-ortho substituted congeners. Furthermore, the key-PBBs determined in Baltic cod liver were formed during this process. The most important hexabromobiphenyl in Baltic cod liver was identified as PBB 155 by parallel synthesis. PBB 155 which was not detected in the technical PBB product analyzed was suggested as an indicator PBB congener suited to decide whether PBB residues originate from the previous use of THBB (low relative abundance of PBB 155) or TOBB/TDBB (high relative abundance of PBB 155). The latter scenario was found to be valid for the Baltic cod liver sample. Thus, PBBs in the Baltic Sea appeared to originate from partially-weathered residues of PBB 209.

Photolytic dehalogenation of the marine halogenated natural product Q1

The marine halogenated natural product 2,3,3',4,4',5,5'-heptachloro-1'-methyl-1,2'-bipyrrole (Q1) has been detected in high-trophic level biota throughout the world. In this study we UV-irradiated Q1 in order to produce hexahalogenated 1'-methylbipyrroles (Cl(6)-MBPs). Q1 was transformed with half-lives of <5 min. Already after 5 min, all of the five existing Cl(6)-MBPs (H1-H5) were detected in the irradiated sample. Only one Cl(6)-MBP (2,3,3',4',5,5'-hexachloro-1'-methyl-1,2'-bipyrrole (MBP-77, H2) has been previously described in the literature. H5 was identified as 2,3,3',4,4',5'-hexachloro-1'-methyl-1,2'-bipyrrole (MBP-75) by a specific fragment ion detected by GC/ECNI-MS. Fractionations of the irradiation mixture by reversed-phase HPLC followed by (1)H NMR analysis led to the structure of H4, i.e. 2,3,3',4,4',5-hexachloro-1'-methyl-1,2'-bipyrrole (MBP-74). H1 and H3 showed virtually identical (1)H NMR data. Therefore, it could not determined which of either isomers is 2,3,3',4,5,5'-hexachloro-1'-methyl-1,2'-bipyrrole (MBP-76) and which is 2,3,4,4',5,5'-hexachloro-1'-methyl-1,2'-bipyrrole (MBP-78). In addition, two pentachloro-MBPs (P1 and P3) could be traced back to MBP-62 and MBP-69. Cl(6)-MBPs were analyzed in whale blubber from Australia and skua adipose tissue from Antarctica. The marine mammals contained all Cl(6)-MBPs except for the most abundant in the irradiation experiment. The concentrations of the Cl(6)-MBPs amounted to 0.04-1.76% of the concentration of Q1. The highest concentrations of Cl(6)-MBP isomers in the biota samples were found for MBP-76, MBP-77, and MBP-78. These congeners appeared to be the most lipophilic ones owing to the highest retention time in RP-HPLC. Nevertheless, it remained unclear whether the Cl(6)-MBPs were actual halogenated natural products or environmental metabolites of Q1.

Photolytic transformation of polybrominated biphenyls leading to the structures of unknown hexa- to nonabromo-congeners

Polybrominated biphenyls (PBBs) have been used as flame-retardants mainly in the 1970s. Nowadays, they are found as ubiquitous contaminants in environmental samples. 2,2',4,4',5,5'-hexabromobiphenyl (PBB 153) is one of the persistent organic pollutants whose global ban is currently under discussion. Like the polychlorinated biphenyls (PCBs), 209 PBB congeners are existing in theory. However, only approximately 40 PBBs have been identified to date. In this work, we therefore used UV light, a sun simulator and natural sunlight for the photochemical debromination of PBB 209. All techniques led to the reductive debromination of PBB 209 albeit at different speed. Shifts of bromine substituents were not observed. Normal phase and reversed phase high performance liquid chromatography (HPLC) was used for the isolation of 12 reaction products some of which could be identified by (1)H NMR (PBB 202, 201, 197, 208, and 207). The other isolates (PBB 179, 178, 176, 199, 197, 196, and 194) were identified by realization of photolytic transformation studies with all isolates followed by comparison and evaluation of the obtained product spectra. In this way, we were able to establish (relative) retention times of the three nonabromobiphenyls, 9 of the 12 octabromobiphenyls, 14 of the 24 heptabromobiphenyl, and 16 of the 42 hexabromobiphenyls. Data on 24 PBBs are presented for the first time. Evaluation of the samples showed that Br was alternately removed from both phenyl rings and that positions with two vicinal Br substituents were most affected. Likewise, ortho-substituted PBBs were enriched.

Recent developments in the analysis of brominated flame retardants and brominated natural compounds

This article reviews recent literature on the analysis of brominated flame retardants (BFRs) and brominated natural compounds (BNCs). The main literature sources are reviews from the last five years and research articles reporting new analytical developments published between 2003 and 2006. Sample pretreatment, extraction, clean-up and fractionation, injection techniques, chromatographic separation, detection methods, quality control and method validation are discussed. Only few new techniques, such as solid-phase microextraction (SPME) or pressurized liquid extraction (PLE), have been investigated for their ability of combining the extraction and clean-up steps. With respect to the separation of BFRs, the most important developments were the use of comprehensive two-dimensional gas chromatography for polybrominated diphenyl ethers (PBDEs) and the growing tendency for liquid-chromatographic techniques for hexabromocyclododecane (HBCD) stereoisomers and of tetrabromobisphenol-A (TBBP-A). At the detection stage, mass spectrometry (MS) has been developed as well-established and reliable technology in the identification and quantification of BFRs. A growing attention has been paid to quality assurance. Interlaboratory exercises directed towards BFRs have grown in popularity and have enabled laboratories to validate analytical methods and to guarantee the quality of their results. The analytical procedures used for the identification and characterization of several classes of BNCs, such as methoxylated polybrominated diphenyl ethers (MeO-PBDEs) (also metabolites of PBDEs), halogenated methyl or dimethyl bipyrroles (DBPs), are reviewed here for the first time. These compounds were generally identified during the routine analysis of BFRs and have received little attention until recently. For each topic, an overview is presented of its current status.

Polybrominated hexahydroxanthene derivatives (PBHDs) and other halogenated natural products from the Mediterranean sponge Scalarispongia scalaris in marine biota

Structures of polybrominated hexahydroxanthene derivatives (PBHDs) previously detected in commercial fish from the Mediterranean Sea and mussels from New Zealand were assigned to 2,7-dibromo-4a-bromomethyl-1,1-dimethyl-2,3,4,4a,9,9a-hexahydro-1H-xanthene (TriBHD) and 2,5,7-tribromo-4a-bromomethyl-1,1-dimethyl-2,3,4,4a,9,9a-hexahydro-1H-xanthene (TetraBHD) by comparing their gas chromatography/mass spectrometry (GC/MS) features with isolates from an Australian sponge of the Cacospongia genus. Because of the geographic distance between the Mediterranean Sea in Europe (origin of the fish) and Australia (origin of the sponge), a closely related sponge, Scalarispongia scalaris, was collected in the Mediterranean Sea and analyzed for PBHDs and other halogenated compounds. The Mediterranean sponge contained the PBHDs at 37 mg/kg dry weight. Using quantitative standards for the first time, the PBHD concentrations in fish and mussel samples published earlier were re-examined. Concentrations of up to 1 mg/kg TriBHD and 0.5 mg/kg TetraBHD were determined in the lipids. No correlation with 2,2', 4,4', 5,5'-hexachlorobiphenyl (PCB 153) or p,p'-DDE was found, which is in agreement with other marine halogenated natural products detected in the fish samples. Besides the PBHDs, further unknown halogenated compounds were detected in the Mediterranean sponge, some of which were also detected in commercial fish. GC/electron ionization-MS analysis showed that a major mixed-halogenated compound in the sponge had a molecular ion at m/z 480 and contained three bromines, three chlorines, and 9-10 carbons. No corresponding structure has been described for this feature in the scientific literature. This sponge secondary metabolite and potential novel halogenated natural product was also detected in commercial fish. Another prominent mixed halogenated compound detected both in sponge and fish was the dibromotrichloro monoterpene MHC-1 (C(10)H(13)Br(2)Cl(3)).

Bioaccumulation of naturally occurring mixed halogenated dimethylbipyrroles in whale and dolphin products on the Japanese market

Mixed halogenated dimethyl bipyrroles (HDBPs), which are thought to be produced naturally, were quantified in whale and dolphin products marketed for human consumption in Japan. The major component of HDBPs was 3,3',4,4'-tetrabromo-5,5'-dichloro-1,1'-dimethyl -2,2'-bipyrrole (Br(4)Cl(2)-DBP), accounting for 85% of the total of five HDBPs detected, followed by Br(3)Cl(2)-DBP. Mean concentrations of HDBPs ranged from 0.27 microg/g lipid (n = 31) in minke whale (Balaenoptera acutorostrata) from the northwest Pacific Ocean to 11.8 microg/g lipid (n = 33) in bottlenose dolphin (Tursiops trucatus) from the southwest Japanese coastal water. At higher levels, HDBPs made up 37% of the total organohalogen body burden in Dall's porpoise (Phocoenoides dalli), whereas the contribution was less than 8.9% in minke whales. In two data subsets from Baird's beaked whale (Berardius bairdii), the products from the Pacific Ocean contained significantly higher concentrations of HDBPs than those from the Sea of Japan. Furthermore, the geographical distribution of HDBPs did not resemble those of ubiquitous anthropogenic organochlorines, such as polychlorinated biphenyl (PCBs). Higher concentration ratios of SigmaHDBP/SigmaPCB and different patterns of HDBP congeners were observed in whale products from the Asia-Pacific as compared to non-Pacific Ocean mammals reported previously. These results support the hypothesis that HDBPs and anthropogenic organochlorines have different sources and that the consumption of HDBPs by Japanese individuals could be an exposure/health risk.

Marine halogenated natural products of environmental relevance

A wide range and steadily increasing number of halogenated natural products (HNPs) is detected in marine organisms that are not the natural source of these compounds but which have accumulated these HNPs in a similar way as known to occur with anthropogenic halogenated pollutants such as PCBs and DDT. The HNPs have aromatic, aliphatic, and heterocyclic spines and are brominated, chlorinated, or mixed halogenated (Cl and Br). The exact isomer structures of HNPs are often closely related to the anthropogenic POPs, and for some compounds both natural and anthropogenic sources are likely to exist. Some of the HNPs are nonpolar, persistent, and can thus be found even in marine mammals and birds of prey. The most important HNPs detected in top predators are halogenated 1,1'-dimethyl-2,2'-bipyrroles (HDBPs), the heptachloro-1'-methyl-1,2'-bipyrrole Q1, the tetrabromophenoxyanisole isomers 6-MeO-BDE 47 and 2'-MeO-BDE 68, and related compounds. Each of these compounds has been detected in higher trophic biota with concentrations exceeding 1 mg/kg.

Retention-time database of 126 polybrominated diphenyl ether congeners and two Bromkal technical mixtures on seven capillary gas chromatographic columns

The elution order of 126 polybrominated diphenyl ethers (PBDE) was determined for seven different gas chromatographic (GC) stationary phases. The resulting database facilitates selection of the most suitable GC columns for developing a quantitative, congener-specific BDE analysis and the testing of retention prediction algorithms based on structure relationships of GC phases and congener substitution patterns. In addition, co-elutions of the principal BDE congeners with other BDEs and/or with other brominated flame retardants were investigated and, as an application, the composition of two Bromkal mixtures (70-5DE and 79-8DE) was studied.

Biological activity and physicochemical parameters of marine halogenated natural products 2,3,3',4,4',5,5'-heptachloro-1'-methyl-1,2'-bipyrrole and 2,4,6-tribromoanisole

Physicochemical parameters (vapor pressure, water solubility, Henry's law constant) and biological activities of two halogenated natural products frequently detected in marine samples and food were determined. Synthetic 2,3,3',4,4',5,5'-heptachloro-1'-methyl-1,2'-bipyrrole (Q1) and 2,4,6-tribromoanisole (TBA) were available in pure form. The physicochemical parameters were in the range of anthropogenic chlorinated compounds of concern. The aqueous solubilities at 25 degrees C (S(w,25)) of Q1 and TBA were 4.6 microg/L and 12,200 microg/L, respectively, whereas subcooled liquid vapor pressures were 0.00168 Pa (Q1) and 0.06562 Pa (TBA) as measured by the gas chromatographic-retention time technique. Q1 was negative by established test systems for the determination of ethoxyresorufin-O-deethylase (EROD) induction and by sulforhodamine B assay. EROD induction potency was at least 10(-7) times lower than that of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). At a relatively high concentration (20 microM), Q1 inhibited specific binding of 2 nM [(3)H]TCDD to the in vitro-expressed human aryl hydrocarbon receptor (AHR) by 18%; lower concentrations showed no effect. Molecular modeling showed that Q1 is nonplanar, consistent with its relatively modest affinity as an AHR ligand. When tested for cell-growth inhibitory/cytocidal activity in human tumor cells, Q1 was only marginally, if at all, active with an IC(50) value >50 microM compared with five to ten times lower IC(50) values for potent cytotoxins tested in the test system used. Furthermore, standard pesticide tests on insecticidal, herbicidal, and fungicidal activity did not provide any significant activity at highest concentrations. For TBA, the results in all tests were comparable with Q1. The SRB assay was also applied to the halogenated natural product 4,6-dibromo-2-(2',4'-dibromo)phenoxyanisole, but no toxic response was found. Although it was apparent that Q1 and TBA had been proven to have relatively low biological activity in all tests performed, further research is necessary to clarify whether metabolites of the compounds eventually may possess a risk to humans or other living organisms. Nevertheless, the role of Q1 in nature remains uncertain.

Polybrominated methoxy diphenyl ethers (MeO-PBDEs) in fish and guillemot of Baltic, Atlantic and Arctic environments

Arctic cod liver samples from Vestertana Fjord at the Arctic coast of Norway, salmon and guillemot samples from the Baltic Sea and the Atlantic Ocean, and salmon and lamprey larva samples from Kymijoki River in southern Finland were analysed for the occurrence of tri-, tetra- and pentabromomethoxy diphenyl ethers and their concentration levels were estimated. These compounds have previously been identified by other research groups in salmon, seal and dolphin samples. The aim of this study was to find out a possible temporal trend in the concentrations of these compounds in the cod liver samples from years 1987-1998 and to investigate the possible spatial differences in the concentrations in biota samples from the Baltic Sea, Atlantic Ocean, Arctic Sea and contaminated freshwater river. Two most abundant methoxy-tetrabromo diphenyl ether congeners occurred in the same statistically significant ratio in 14 sea biota samples. Levels in lamprey larvae were below detection limit. The origin of these methoxylated bromodiphenyl ethers in biota samples remained unknown. They may be metabolites of polybrominated diphenyl ethers used as flame retardants or compounds of natural origin.

Non-polar halogenated natural products bioaccumulated in marine samples. I. 2,3,3',4,4',5,5'-Heptachloro-1'-methyl-1,2'-bipyrrole (Q1)

This presentation adds new spectroscopic and analytical data on the natural product Q1 that was recently identified by synthesis as 2,3,3('),4,4('),5,5(')-heptachloro-1(')-methyl-1,2(')-bipyrrole. Solid state magic angle spinning 13C NMR data of Q1 is presented as an option for structural proof. Furthermore, the UV spectrum of neat Q1 (absorption maximum at 223 nm) was recorded and, with NMR spectroscopic data, confirmed a twisted bipyrrole ring system. A quantitative standard of Q1 was prepared which allowed to correct previous concentration estimates relative to the electron capture detector response factor of trans-nonachlor. As a result, the actual Q1 response was only 0.65+/-15% of the response factor of trans-nonachlor. Therefore, actual Q1 levels are about 50% higher than the previous estimates. With this result the highest (corrected) Q1 concentration determined to date in the blubber of marine mammals from Australia is 14 mg/kg lipid. Analysis of Q1 and trans-nonachlor in specimens from the German North Sea coast suggests that harbor seals are more able to metabolize Q1 than harbor porpoises. Finally, we calculated that 79 congeners of Q1 (i.e. lower chlorinated 1(')-methyl-1,2(')-bipyrroles) are theoretically possible and present their structures.