Marine sponge: a potential source for methoxylated polybrominated diphenyl ethers in the Asia-Pacific food web

Persistent and Bioaccumulative Halogenated Natural Products in Various Tropical Reef Fish Species from the Seychelles, Western Indian Ocean

Gas chromatography with electron capture negative ion mass spectrometry (GC/ECNI-MS) was used to quantify and compare halogenated natural products (HNPs) and selected anthropogenic persistent organic pollutants (POPs) in individual samples of 17 fish species from the Seychelles (Western Indian Ocean). The sum-HNP amounts (9.5-1100 ng/g lipid mass (lm)) were between 1 and 2 orders of magnitude higher than those of the sum of seven abundant polychlorinated biphenyl (PCB) congeners (0.2-15 ng/g lm) and dichlorodiphenyltrichloroethane-related compounds (DDTs) (<1.1-43 ng/g lm). Within the group of HNPs, the two tetrabrominated phenoxyanisoles (aka methoxylated diphenyl ethers, MeO-BDEs), 2'-MeO-BDE 68 ≫ 6-MeO-BDE 47, were predominant in most cases. Pearson correlation analysis showed that MeO-BDE levels were positively correlated with less abundant HNPs (2,2'-diMeO-BB 80, 2',6-diMeO-BDE 68, and Br6-DBP) (p < 0.01). Accordingly, HNPs, rather than PCBs and DDTs, were the predominant polyhalogenated contaminants in the current species.

MPoMA protects against lung epithelial cell injury via p65 degradation

Numerous cases of lung injury caused by viral infection were reported during the coronavirus disease-19 pandemic. While there have been significant efforts to develop drugs that block viral infection and spread, the development of drugs to reduce or reverse lung injury has been a lower priority. This study aimed to identify compounds from a library of compounds that prevent viral infection that could reduce and prevent lung epithelial cell damage. We investigated the cytotoxicity of the compounds, their activity in inhibiting viral spike protein binding to cells, and their activity in reducing IL-8 production in lung epithelial cells damaged by amodiaquine (AQ). We identified N-(4-(4-methoxyphenoxy)-3-methylphenyl)-N-methylacetamide (MPoMA) as a non-cytotoxic inhibitor against viral infection and AQ-induced cell damage. MPoMA inhibited the expression of IL-8, IL-6, IL-1β, and fibronectin induced by AQ and protected against AQ-induced morphological changes. However, MPoMA did not affect basal IL-8 expression in lung epithelial cells in the absence of AQ. Further mechanistic analysis confirmed that MPoMA selectively promoted the proteasomal degradation of inflammatory mediator p65, thereby reducing intracellular p65 expression and p65-mediated inflammatory responses. MPoMA exerted potent anti-inflammatory and protective functions in epithelial cells against LPS-induced acute lung injury in vivo. These findings suggest that MPoMA may have beneficial effects in suppressing viral infection and preventing lung epithelial cell damage through the degradation of p65 and inhibition of the production of inflammatory cytokines.

Comparison of volatile aroma compounds in commercial surimi and their products from freshwater fish and marine fish and aroma fingerprints establishment based on metabolomics analysis methods

Understanding the differences in odors of freshwater and marine fish surimi and their products is important for the quality control of surimi products. Aroma compounds in silver carp surimi and three kinds of marine fish surimi and their products were identified by gas chromatography-mass spectrometry/olfactometry, and aroma fingerprints of them were established based on metabolomics analysis methods. Silver carp surimi and surimi products showed the highest "fresh fish" and "grassy, earthy" notes, while the marine fish surimi and their products presented a strong "sea breeze-like" odor. Five Br-containing compounds (sea breeze-like) were identified in the marine fish samples. The aroma fingerprints showed that the odor compositions of freshwater and marine surimi/surimi products were divided into two categories, and the marine fish surimi and their products also showed differences in odors. Furthermore, four commercial surimi and their products could be distinguished according to 33 and 28 differential aroma components, respectively.

A Review of Hydroxylated and Methoxylated Brominated Diphenyl Ethers in Marine Environments

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and methoxylated polybrominated diphenyl ethers (MeO-PBDEs) are present in the marine environment worldwide. Both OH-PBDEs and MeO-PBDEs are known natural products, whereas OH-PBDEs may also be metabolites of PBDEs. There is growing concern regarding OH-PBDEs as these compounds seem to be biological active than PBDEs. In the present study, we reviewed the available data on the contamination of OH/MeO-PBDEs in the marine environment worldwide, including seawater, marine sediment, marine plants, invertebrates, fish, seabirds and mammals. Bioaccumulation and biomagnification of OH/MeO-PBDEs in the marine food web were summarized as well. This study also proposes the future research of OH/MeO-PBDEs, including the production and the synthesis pathway of OH/MeO-PBDEs, the toxicokinetics of OH/MeO-PBDEs and the toxicology and human exposure risk assessment.

Identification of novel halogenated naturally occurring compounds in marine biota by high-resolution mass spectrometry and combined screening approaches

Marine animals, plants or bacteria are a source of bioactive naturally-occurring halogenated compounds (NHCs) such as bromophenols (BPs), bromoanisoles (BAs) and hydroxylated or methoxylated analogues of polybrominated diphenyl ethers (HO-PBDEs, MeO-PBDEs) and bromobiphenyls (HO-BBs, MeO-BBs). This study applied a comprehensive screening approach using liquid chromatography high-resolution mass spectrometry and combining target, suspect and non-target screening with the aim to identify new hydroxylated NHCs which might be missed by commonly applied gas chromatographic methods. 24 alga samples, 4 sea sponge samples and 7 samples of other invertebrates were screened. Target screening was based on 19 available reference standards of BPs, (di)OH-BDEs and diOH-BBs and yielded seven unequivocally identified compounds. 6-OH-BDE47 was the most frequently detected compound with a detection frequency of 31%. Suspect screening yielded two additional compounds identified in alga samples as well as 17 and 8 compounds identified in sea sponge samples of Lamellodysidea sp. and Callyspongia sp., respectively. The suspect screening results presented here confirmed the findings of previous studies conducted on sea sponge samples of Lamellodysidea sp. and Callyspongia sp. Additionally, in Lamellodysidea sp. and Callyspongia sp. 13 and 4 newly identified NHCs are reported including heptabrominated diOH-BDE, monochlorinated pentabrominated diOH-BDE, hexabrominated OH-MeO-BDE and others. Non-target screening allowed the identification of 31 and 20 polyhalogenated compounds in Lamellodysidea sp. and Callyspongia sp. samples, respectively. Based on the obtained fragmentation spectra, polybrominated dihydroxylated diphenoxybenzenes (diOH-PBDPBs), such as hepta-, octa- and nonabrominated diOH-BDPBs, could be identified in both species. To our knowledge, this study is the first report on the environmental presence of OH-PBDPBs.

Naturally occurring organobromine compounds (OBCs) including polybrominated dibenzo-p-dioxins in the marine sponge Hyrtios proteus from The Bahamas

Halogenated natural products (HNPs) were identified from organic extracts of the marine sponge Hyrtios proteus from The Bahamas using gas chromatography with electron capture negative ion mass spectrometry and non-targeted gas chromatography with electron ionization mass spectrometry. The HNPs found have similar properties to anthropogenic persistent organic pollutants (POPs). Two ortho-methoxy brominated diphenyl ethers (MeO-BDEs) 2'-MeO-BDE 68 and 6-MeO-BDE 47 were the most abundant compounds. Fourteen other MeO-BDEs were detected along with several polybrominated dibenzo-p-dioxins (PBDDs) (1,3,7-triBDD, 1,3,6,8-tetraBDD and 1,3,7,9-tetraBDD) and MeO-PBDDs. Further analysis of a higher trophic level octopus (Octopus maya) from the same FAO fishing area showed that the major HNPs detected in Hyrtios proteus were also predominant. Moreover, HNPs were more than 30-fold higher in abundance than the major POPs in the octopus, i.e., polychlorinated biphenyls. Hence, Caribbean marine organisms, including those potentially used for food, harbor relatively high concentrations of HNPs.

Organic pollutants in deep sea: Occurrence, fate, and ecological implications

The deep sea - an oceanic layer below 200 m depths - has important global biogeochemical and nutrient cycling functions. It also receives organic pollutants from anthropogenic sources, which threatens the ecological function of the deep sea. In this Review, critically examined data on the distribution of organic pollutants in the deep sea to outline the role of biogeochemical and geophysical factors on the global distribution and regional chemodynamics of organic pollutants in the deep sea. We found that the contribution of deep water formation to the influx of perfluorinated compounds reached a maximum, following peak emission, faster in young deep waters (< 10 years) compared to older deep waters (> 100 years). For example, perfluorinated compounds had low concentrations (< 10 pg L^-1) and vertical variations in the South Pacific Ocean where the ocean currents are old (< 1000 years). Steep geomorphologies of submarine canyons, ridges, and valleys facilitated the transport of sediments and associated organic pollutants by oceanic currents from the continental shelf to remote deep seas. In addition, we found that, even though an estimated 1.2-4.2 million metric tons of plastic debris enter the ocean through riverine discharge annually, the role of microplastics as vectors of organic pollutants (e.g., plastic monomers, additives, and attached organic pollutants) in the deep sea is often overlooked. Finally, we recommend assessing the biological effects of organic pollutants in deep sea biota, large-scale monitoring of organic pollutants, reconstructing historical emissions using sediment cores, and assessing the impact of deep-sea mining on the ecosystem.

Occurrence of Halogenated Organic Pollutants in Hadal Trenches of the Western Pacific Ocean

The hadal trenches are the most remote and inaccessible habitats on earth and were once believed to be pristine. A recent study has reported the detection of high levels of persistent organic pollutants (POPs), including polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs), in endemic amphipods from two hadal trenches (Mariana and Kermadec) in the Western Pacific, implicating that the trenches are indeed polluted. However, a fundamental question remains unanswered, if and to what extent such the physical environment of the trenches is polluted by POPs. In this study, we sampled Mariana, Mussau, and New Britain trenches and analyzed samples of amphipods, sediment, and suspended particulate matter (SPM). Our results show that the amphipods contained elevated levels of PCBs and PBDEs, comparable to those reported in the earlier study. We also detected significantly high concentrations (up to 1343 ng g^-1 lw) of chlorinated pesticides, such as dichlorodiphenyltrichloroethanes and chlordanes. Furthermore, four brominated natural products (BNPs), which structurally resembled methoxylated brominated diphenyl ethers or polybrominated biphenyls, were identified in the endemic amphipods. However, neither POPs nor BNPs were detected in sediments or SPM. Taken together, we propose that the POPs detected in endemic amphipods likely resulted from bioaccumulation by feeding on polluted large detritus (e.g., carrion) falling to the trench bottoms from the surface ocean.

Will Climate Change Influence Production and Environmental Pathways of Halogenated Natural Products?

Thousands of halogenated natural products (HNPs) pervade the terrestrial and marine environment. HNPs are generated by biotic and abiotic processes and range in complexity from low molecular mass natural halocarbons (nHCs, mostly halomethanes and haloethanes) to compounds of higher molecular mass which often contain oxygen and/or nitrogen atoms in addition to halogens (hHNPs). nHCs have a key role in regulating tropospheric and stratospheric ozone, while some hHNPs bioaccumulate and have toxic properties similar those of anthropogenic-persistent organic pollutants (POPs). Both chemical classes have common sources: biosynthesis by marine bacteria, phytoplankton, macroalgae, and some invertebrate animals, and both may be similarly impacted by alteration of production and transport pathways in a changing climate. The nHCs scientific community is advanced in investigating sources, atmospheric and oceanic transport, and forecasting climate change impacts through modeling. By contrast, these activities are nascent or nonexistent for hHNPs. The goals of this paper are to (1) review production, sources, distribution, and transport pathways of nHCs and hHNPs through water and air, pointing out areas of commonality, (2) by analogy to nHCs, argue that climate change may alter these factors for hHNPs, and (3) suggest steps to improve linkage between nHCs and hHNPs science to better understand and predict climate change impacts.

Determination of newly synthesized dihydroxylated polybrominated diphenyl ethers in sea fish by gas chromatography-tandem mass spectrometry

Dihydroxylated polybrominated diphenyl ethers (diOH-PBDEs) can be natural products of marine organisms or the metabolites of PBDEs. The optimal determination method and concentration of diOH-PBDEs in seafood are unknown due to a lack of commercially available standards. In the present study, diOH-PBDEs were synthesized, and an efficient measurement method for OH-PBDEs and diOH-PBDEs in sea fish muscle samples, including extraction, clean-up and gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis, was established. Pressurized liquid extraction (PLE) followed by partitioning with a KOH solution and florisil cartridge clean-up proved to be a reliable and robust method for detecting all OH-PBDEs/diOH-PBDEs. GC-MS/MS with an electron ionization (EI) source analysis was a sensitive analytical instrument for OH-PBDEs/diOH-PBDEs. The recovery using this method ranged from 19% to 101%, 28%-88% and 42%-90% for 10 ng, 20 ng and 40 ng spiking levels, respectively. The equipment detection limits (EDLs) were in the range of 0.31-2.78 pg/μL, and the limits of detection (LOD) for the method were in the range of 5.07-38.74 pg/g wet weight. Concentrations of diOH-PBDEs in the marine fish muscle samples were in the range of 32.43-1528.63 pg/g wet weight. Similar compositions of OH-PBDEs/diOH-PBDEs were found within the same family of marine fish.

Sponge-derived polybrominated diphenyl ethers and dibenzo-p-dioxins, irreversible inhibitors of the bacterial α-d-galactosidase

An integrated in vitro and in silico approach was applied to evaluate the potency of hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and spongiadioxins (OH-PBDDs) isolated from Dysidea sponges on the activity of the recombinant α-d-galactosidase of the GH36 family. It was revealed for the first time that all compounds rapidly and apparently irreversibly inhibited the bacterial α-d-galactosidase. The structure-activity relationship study in the series of OH-PBDEs showed that the presence of an additional hydroxyl group in 5 significantly enhanced the potency (IC50 4.26 μM); the increase of bromination in compounds from 1 to 3 increased their potency (IC50 41.8, 36.0, and 16.0 μM, respectively); the presence of a methoxy group decreased the potency (4, IC50 60.5 μM). Spongiadioxins 6, 7, and 8 (IC50 16.6, 33.1, and 28.6 μM, respectively) exhibited inhibitory action comparable to that of monohydroxylated diphenyl ethers 1-3. Docking analysis revealed that all compounds bind in a pocket close to the catalytic amino acid residues. Molecular docking detected significant compound-enzyme interactions in the binding sites of α-d-galactosidase. Superimposition of the enzyme-substrate and the enzyme-inhibitor complexes showed that their binding sites overlap.

Different profiles of naturally produced and anthropogenic organohalogens in the livers of cetaceans from the Sea of Japan and the North Pacific Ocean

Levels and profiles of naturally produced halogenated bipyrroles (Br₄Cl₂-DBP and Cl₇-MBP), methoxylated tetrabromodiphenyl ethers (6-MeO-BDE47), anthropogenic perfluoroalkyl substances (PFASs) and legacy persistent organic pollutants (POPs) were investigated in the livers of 14 cetaceans from the Sea of Japan and the North Pacific Ocean. The concentrations of Br₄Cl₂-DBP (4 to 4900 ng/g-wet), Cl₇-MBP (16 to 3960 ng/g-wet) and 6-MeO-BDE47 (7 to 190 ng/g-wet) were higher in the order of killer whales > toothed whales > baleen whales. Profiles of PFASs were dominated by perfluoroundecanoic and perfluorotridecanoic acids (10 to 540 ng/g-wet), sum of which accounted for 70% of total measured PFASs. Regional difference was observed for Cl₇-MBP and PFASs, which were higher in the Sea of Japan, whereas Br₄Cl₂-DBP was in the North Pacific Ocean. Specific accumulation pattern of these natural contaminants in cetaceans around northern Japan could help compare the exposure profile of PFASs and POPs among other geographic regions.

Mass-flow-based removal and transformation potentials for TBBPA, HBCDs and PBDEs during wastewater treatment processes

At a sewage treatment plant, 27 polybrominated diphenyl ethers, 17 methoxylated brominated diphenyl ethers, nine hydroxylated brominated diphenyl ethers, three hexabromocyclododecane diastereomers, and tetrabromobisphenol A were monitored at five major treatment stages (the influent, primary settlement stage, biological reaction stage, secondary settlement stage, and the UV irradiation disinfection stage). Hexabromocyclododecanes were the dominant chemicals, contributing 40% of the total concentrations of the chemicals in the dissolved phase of the sewage. Brominated flame retardant mass flow in the wastewater was lower after than before the biological reaction stage, and more than 70% of the inflowing mass load was removed from the mainstream wastewater by becoming associated with the sludge. More than half of mass loads of parent brominated flame retardants in the wastewater were removed after the treatments, but up to 10% of the initial mass loads remained in the final effluent and was expected to be released into the aquatic environment. The hydroxylated and methoxylated brominated diphenyl ether concentrations decreased by <25%, much less than the polybrominated diphenyl ethers. It is possible that hydroxylated and methoxylated polybrominated diphenyl ethers formed through the transformation of polybrominated diphenyl ethers during the biological reactions of treatment processes.

Determination of phenolic organohalogens in human serum from a Belgian population and assessment of parameters affecting the human contamination

Many in vitro or in vivo studies highlighted the potential deleterious effects of phenolic organohalogenated compounds (POHs) on the health, particularly on the thyroid system homeostasis, however few large scale human epidemiological studies have been carried out, especially in Europe. Further studies monitoring the human contamination by POHs, the sources of exposure and the influence of these compounds on thyroid health are still needed. Therefore we determined the concentrations of 16 POHs (pentachlorophenol (PCP), tetrabromobisphenol A (TBBPA), 4 bromophenols (BPs), 3 hydroxy-polybromodiphenylethers (OH-PBDEs) and 7 hydroxy-polychlorobiphenyls (OH-PCBs)) in serum from 274 people aged from 18 to 76years old living in Liege (Belgium) and the surrounding area. A questionnaire about their alimentary habits, life style and home environment was also administered to the volunteers. The predominant compound measured in the population was PCP (median concentration of 593.0pgmL^-1). 4-OH-CB 107, 4-OH-CB 146 and 4-OH-CB 187 were detected in all samples and contributed for 75% of the sum of OH-PCBs (ΣOH-PCBs). The median measured in our population for ΣOH-PCBs was 143.7pgmL^-1. TBBPA and 2,4,6-tribromophenol were detected in 31% and 63.8% of the samples respectively while the detection frequency observed for the other BPs and the OH-PBDEs was close to zero. We computed multivariate regression models in order to assess the influence of demographic and lifestyle parameters on the PCP and ΣOH-PCBs contamination levels. Significant correlation was found between the PCP concentration and sex, smoker status, sea fish consumption and level of education, although the model seemed to be a poor (R²=0.14) predictor of the PCP concentration. The model computed for ΣOH-PCBs was more explanatory (R²=0.61) and involved age, BMI and sea fish consumption. Finally, we assessed the parameters affecting the ΣOH-PCBs/ΣPCBs ratio. The model proposed involved age, BMI, smoker status and parent PCB level, and explained 41% of the variability of the ΣOH-PCBs/ΣPCBs ratio.

Uptake and biotransformation of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) in four marine microalgae species

Hydroxylated- and methoxylated- polybrominated diphenyl ethers (OH-PBDEs and MeO-PBDEs) are more toxic than PBDEs and occur widely in the marine environment, and yet their origins remain controversial. In this study, four species of microalgae (Isochrysis galbana, Prorocentrum minimum, Skeletonema grethae and Thalassiosira pseudonana) were exposed to BDE-47, which is synthetic and is the predominant congener of PBDEs in the environment. By chemical analysis after incubation of 2 to 6 days, the efficiency of uptake of BDE-47 and, more importantly, the potential of undergoing biotransformation to form OH-PBDEs and MeO-PBDEs by the microalgae were investigated. Growth rates of these axenic microalgae were not affected upon exposure to environmentally relevant concentrations (0.2–20 μg BDE-47 L⁻¹), and accumulation ranged from 0.772 ± 0.092 μg BDE-47 g⁻¹ lipid to 215 ± 54 μg BDE-47 g⁻¹ lipid within 2 days. Debromination of BDE-47 and formation of BDE-28 occurred in all microalgae species (0.01 to 0.87%), but biotransformation to OH-PBDEs was only found in I. galbana upon exposure to extremely high concentration. The results of this study showed that biotransformation of microalgae species is unlikely an explanation for the OH-PBDEs and MeO-PBDEs found in the marine environment.

Monohydroxylated Polybrominated Diphenyl Ethers (OH-PBDEs) and Dihydroxylated Polybrominated Biphenyls (Di-OH-PBBs): Novel Photoproducts of 2,6-Dibromophenol

Hydroxylated polybromodiphenyl ethers (OH-PBDEs) are emerging aquatic pollutants, but their origins in the environment are not fully understood. There is evidence that OH-PBDEs are formed from bromophenols, but the underlying transformation processes remain unknown. Here, we investigate if the photoformation of OH-PBDEs from 2,6-dibromophenol in aqueous solution involves 2,6-bromophenoxyl radicals. After the UV irradiation of an aqueous 2,6-dibromophenol solution, HPLC-LTQ-Orbitrap MS and GC-MS analysis revealed the formation of a OH-PBDE and a dihydroxylated polybrominated biphenyl (di-OH-PBB). Both dimeric photoproducts were tentatively identified as 4'-OH-BDE73 and 4,4'-di-OH-PBB80. In addition, three debromination products (4-OH-BDE34, 4'-OH-BDE27, and 4,4'-di-OH-PBBs) were observed. Electron paramagnetic resonance spectroscopy revealed the presence of a 2,6-dibromophenoxyl radical with a six-line spectrum (a(H) (2 meta) = 3.45 G, a(H) (1 para) = 1.04 G, g = 2.0046) during irradiation of a 2,6-dibromophenol solution in water. The 2,6-dibromophenoxyl radical had a relatively long half-life (122 ± 5 μs) according to laser flash photolysis experiments. The para-para C-C and O-para-C couplings of these 2,6-dibromophenoxyl radicals are consistent with the observed formation of both dimeric OH-PBDE and di-OH-PBB photoproducts. These findings show that bromophenoxyl radical-mediated phototransformation of bromophenols is a source of OH-PBDEs and di-OH-PBBs in aqueous environments that requires further attention.

Formation of hydroxylated polybrominated diphenyl ethers from laccase-catalyzed oxidation of bromophenols

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have been frequently found in the marine biosphere as emerging organic contaminants. Studies to date have suggested that OH-PBDEs in marine biota are natural products. However, the mechanisms leading to the biogenesis of OH-PBDEs are still far from clear. In this study, using a laccase isolated from Trametes versicolor as the model enzyme, we explored the formation of OH-PBDEs from the laccase-catalyzed oxidation of simple bromophenols (e.g., 2,4-DBP and 2,4,6-TBP). Experiments under ambient conditions clearly showed that OH-PBDEs were produced from 2,4-DBP and 2,4,6-TBP in presence of laccase. Polybrominated compounds 2'-OH-BDE68, 2,2'-diOH-BB80, and 1,3,8-TrBDD were identified as the products from 2,4-DBP, and 2'-OH-BDE121 and 4'-OH-BDE121 from 2,4,6-TBP. The production of OH-PBDEs was likely a result of the coupling of bromophenoxy radicals, generated from the laccase-catalyzed oxidation of 2,4-DBP or 2,4,6-TBP. The transformation of bromophenols by laccase was pH-dependant, and was also influenced by enzymatic activity. In view of the abundance of 2,4-DBP and 2,4,6-TBP and the phylogenetic distribution of laccases in the environment, laccase-catalyzed conversion of bromophenols may be potentially an important route for the natural biosynthesis of OH-PBDEs.

Investigation of bioaccumulation and biotransformation of polybrominated diphenyl ethers, hydroxylated and methoxylated derivatives in varying trophic level freshwater fishes

The concentrations and distributions of polybrominated diphenyl ethers (PBDEs) and their hydroxylated and methoxylated derivatives (OH- and MeO-BDEs) were determined in seven representative fish species from a river in the Republic of Korea. The PBDEs and their derivatives were found to be accumulated in the internal organs of the fish to different extents. PBDEs were preferentially accumulated in the internal organs rather than muscle tissue, and especially, showed increasing accumulation tendencies with increasing bromination level in liver. The OH-BDEs and MeO-BDEs were preferentially accumulated in the liver and gastrointestinal tract, respectively. MeO-BDE concentrations were found to increase according to relative trophic level, suggesting that the PBDE derivatives can be biomagnified to a greater extent than the parent PBDEs in freshwater food webs. In a comparison with the dissolved analyte concentrations in the water that were measured by using semi-permeable membrane devices, the greater uptake of non-ortho substituted MeO-BDEs by fish was observed.

Complexity of naturally produced polybrominated diphenyl ethers revealed via mass spectrometry

Polybrominated diphenyl ethers (PBDEs) are persistent and bioaccumulative anthropogenic and natural chemicals that are broadly distributed in the marine environment. PBDEs are potentially toxic due to inhibition of various mammalian signaling pathways and enzymatic reactions. PBDE isoforms vary in toxicity in accordance with structural differences, primarily in the number and pattern of hydroxyl moieties afforded upon a conserved core structure. Over four decades of isolation and discovery-based efforts have established an impressive repertoire of natural PBDEs. Based on our recent reports describing the bacterial biosyntheses of PBDEs, we predicted the presence of additional classes of PBDEs to those previously identified from marine sources. Using mass spectrometry and NMR spectroscopy, we now establish the existence of new structural classes of PBDEs in marine sponges. Our findings expand the chemical space explored by naturally produced PBDEs, which may inform future environmental toxicology studies. Furthermore, we provide evidence for iodinated PBDEs and direct attention toward the contribution of promiscuous halogenating enzymes in further expanding the diversity of these polyhalogenated marine natural products.

Hydroxylated, methoxylated, and parent polybrominated diphenyl ethers (PBDEs) in the inland environment, Korea, and potential OH- and MeO-BDE source

The concentrations, congener profiles, and phase-specific distribution profiles of 27 polybrominated diphenyl ethers and 10 hydroxylated and 18 methoxylated brominated diphenyl ethers (OH- and MeO-BDEs; later called structural analogues of PBDEs) were determined in surface soil, water, air, and vegetation from the southeastern city of Busan, Korea for 2010-2011. The total PBDE concentrations were 0.18-7.7 ng/g in soil, 6.3-87 pg/L [corrected] in water, 5.3-16 pg/m(3) in air, and 0.06-0.22 ng/g in vegetation. The OH- and MeO-BDE concentrations were lower than the parent PBDE concentrations in soil samples but OH-BDEs were much greater in the water samples and MeO-BDEs were much greater in the air samples. The relative concentrations of the PBDEs and their structural analogues varied depending on the type and homologue of the degradation product, the substituent position, and the characteristics of the environmental medium. In particular, the OH-BDEs were not found in air samples and the OH-penta BDEs were not detected in any of the matrices. The dominance of the ortho-substituted structural analogues found in water and vegetation suggested that they may have natural sources, but different substituent patterns were found in the air and soil samples, suggesting that the structural analogues had different formation mechanisms in these media.

Dietary exposure to phenolic and methoxylated organohalogen contaminants in relation to their concentrations in breast milk and serum in Japan

This study investigated human exposure to neutral, phenolic, and methoxylated organohalogen contaminants (OHCs) in a duplicate diet study to evaluate their concentrations in breast milk and serum of Okinawan people from Japan during 2004-2009. Dietary intakes of phenolic OHCs were predominantly 2,4,6-tribromophenol (TriBP), followed by tetrabromobisphenol A (TBBPA), and 6-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (6-OH-BDE47). After exposure, TriBP and TBBPA were transferred to breast milk, whereas 6-OH-BDE47 was selectively retained in serum. Despite a lower dietary exposure to pentachlorophenol and 4-hydroxy-CB187, both were retained in serum. For the methoxylated OHCs, 2,4,6-tribromoanisole (TriBA) and 6-methoxy-BDE47 were the predominant dietary contaminants, of which TriBA was present in both breast milk and serum, whereas 6-methoxy-BDE47 was selectively transferred to breast milk. These findings suggest that dietary exposure to phenolic and methoxylated OHCs may result in differential partitioning between breast milk and serum with different pharmacokinetic or exposure routes.