Deriving in Vivo Bioconcentration Factors of a Mixture of Fragrance Ingredients Using a Single Dietary Exposure and Internal Benchmarking.

Chemicals in mixtures that are hydrophobic with Log KOW > 4 are potentially bioaccumulative. Here, we evaluate an abbreviated and benchmarked in vivo BCF measurement methodology by exposing rainbow trout to a mixture of eight test chemicals found in fragrance substances and three benchmark chemicals (musk xylene (MX), hexachlorobenzene (HCB) and PCB52) via a single contaminated feeding event followed by a 28-day depuration period. Concentrations of HCB and PCB52 in fish did not decline significantly (their apparent depuration rate constants, kT, were close to zero), whereas kT for MX was 0.022 d-1. The test chemicals were eliminated much more rapidly than the benchmark chemicals ( kT > 0.117 d-1). The bioconcentration factors (BCFA) for the test chemicals were in the range of 273 L kg-1 (8-cyclohexadecen-1-one (globanone)) to 1183 L kg-1 (α-pinene); the benchmarked BCFs (BCFG) calculated relative to HCB ranged from 238 L kg-1 (globanone) to 1147 L kg-1 (α-pinene). BCFG were not significantly different from BCFA but had smaller standard errors. BCFs derived here agreed well with values previously measured using the OECD 305 test protocol. We conclude that it will be feasible to derive BCFs of chemicals in mixtures using a single dietary exposure and chemical benchmarking.

Novel octabrominated phenolic diphenyl ether identified in blue mussels from the Swedish West Coast.

Hydroxylated (OH-) and methoxylated (MeO-) polybrominated diphenyl ethers (PBDEs) are compounds present in the marine environment and OH-PBDEs are of toxicological concern and are therefore of interest to monitor in the environment. A phenolic octaBDE was tentatively identified in the phenolic fraction of previously analyzed mussel samples after methylation of the halogenated phenolic compounds (HPCs). The aim of the present study was to confirm the identity of this compound in blue mussels and investigate whether the analyte is diOH- and/or OH-MeO-octaBDE. Two reference standards, 6,6'-dimethoxy-2,2',3,3',4,4',5,5'-octabromodiphenyl ether (6,6'-diMeO-BDE194) and 6-ethoxy-6'-methoxy-2,2',3,3',4,4',5,5'-octabromodiphenyl ether (6-EtO-6'-MeO-BDE194) were prepared via O-arylation of 2,3,4,5-tetrabromo-6-methoxyphenol and 2,3,4,5-tetrabromo-6-ethoxyphenol, respectively, with a novel unsymmetrical diaryliodonium salt, 2,3,4,5-tetrabromo-6-methoxydiphenyliodonium triflate. The GC retention time and GC/MS spectrum of the synthesized 6,6'-diMeO-BDE194 correspond well with the analyte in the methylated phenolic fraction of a mussel extract from a previous study. Structural analysis performed in this study indicate that the synthesized 6,6'-diMeO-BDE194 and 6-EtO-6'-MeO-BDE194 correspond well with 6-hydroxy-6'-methoxy-2,2',3,3',4,4',5,5'-octabromodiphenyl ether (6-OH-6'-MeO-BDE194) after methylation and ethylation, respectively, of the HPCs in the mussel extracts. The compound 6-OH-6'-MeO-BDE194 was identified and quantified in new mussels, sampled in 2012 from two locations on the Swedish west coast, with geometric mean concentrations of 3700 and 410 ng/g fat, respectively.

Powerful GC-TOF-MS Techniques for Screening, Identification and Quantification of Halogenated Natural Products.

Comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC×GC TOFMS) and gas chromatography/high-resolution time-of-flight mass spectrometry (GC-HRT) were used to detect and identify halogenated natural products (HNPs) in tissue homogenate, in this case brominated analytes present in a marine snail. Two classes of brominated anthropogenic compounds, polybrominated diphenyl ethers (PBDEs) and brominated dibenzofurans, were analyzed for comparison. Following conventional preparation, the sample was analyzed using GC×GC-TOF-MS. Isotope ratio scripts were used to compile a list of putatively brominated analytes from amongst the thousands of features resolved in the two-dimensional chromatogram. The structured nature of the chromatogram was exploited to propose identifications for several classes of brominated compounds, and include additional candidates that fell marginally outside the script tolerances. The sample was subsequently analyzed by GC-HRT. The high-resolution mass spectral data confirmed many formula assignments, facilitated confident assignment of an alternate formula when an original proposal did not hold, and enabled unknown identification. Identified HNPs include hydroxylated and methoxylated PBDE analogs, polybrominated dibenzo-p-dioxins (PBDDs) and hydroxyl-PBDDs, permitting the environmental occurrence and fate of such compounds to be studied.

Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) in seven different marine bird species from Iceland.

Data on distribution, concentration and trends of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) is scarce in biota from the sub-Arctic region of the Atlantic. The present study is an investigation on PBDE and HBCD concentrations in eggs from seven marine bird species from Iceland, i.e. common eider (Somateria mollissima), arctic tern (Sterna paradisaea), guillemot (Uria aalge), fulmar (Fulmarus glacialis), lesser black-backed gull (Larus fuscus), great black-backed gull (Larus marinus) and great skua (Stercorarius skua). Concentrations of sum PBDEs ranged from 44 ng g(-1)fat in eider eggs to 2400 ng g(-1)fat in great skua eggs. The contribution of different PBDE congeners to the sum concentration differed between species. Concentration of HBCDs (sum of α-,ß(-) and γ-HBCD) ranged from 1.3 ng g(-1)fat in arctic tern eggs to 41 ng g(-1)fat in great black-backed gull. PCA on PBDE and HBCD shows different trends between the two BFR groups, further indicating different sources/usage. Investigations on any potential health or population effects of environmental pollutants on the great skua are advised since both the PBDE and HBCD concentrations are high.

Seasonal variations of hydroxylated and methoxylated brominated diphenyl ethers in blue mussels from the Baltic Sea.

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and methoxylated polybrominated diphenyl ethers (MeO-PBDEs) found at high levels in the Baltic biota are mainly natural products, but can also be formed through metabolism or abiotic oxidation of polybrominated diphenyl ethers (PBDEs). The formation of OH-PBDEs is of concern since there is growing evidence of phenolic toxicity. This study investigates seasonal variations in levels of OH-PBDEs and MeO-PBDEs, focusing on an exposed species, the blue mussel (Mytilus edulis), sampled in the Baltic Sea in May, June, August and October of 2008. Both the OH-PBDE and MeO-PBDE levels in the mussels showed seasonal variations from May to October, the highest concentration of each congener appearing in June. The seasonal variation was more marked for OH-PBDEs than in MeO-PBDEs, but all congeners showed the same trends, except 6-MeO-BDE47 and 2'-MeO-BDE68, which did not significantly decline in concentrations after June. Biotic or abiotic debromination is suggested as a possible reason for the rapid decrease in methoxylated penta- and hexa-BDE concentrations observed in blue mussels from June to August, while the tetraBDE concentrations were stable. In addition, 1,3,7/1,3,8-tribrominated dibenzo-p-dioxins showed the same seasonal variation. The seasonal variations indicates natural formation and are unlikely to be due to transformation of anthropogenic precursors. The levels of PBDEs were fairly constant over time and considerably lower than those of the OH-PBDEs and MeO-PBDEs. The timing of the peaks in concentrations suggests that filamentous macro-algae may be important sources of these compounds found in the blue mussels from this Baltic Sea location.

Brominated phenols, anisoles, and dioxins present in blue mussels from the Swedish coastline.

INTRODUCTION: Naturally occurring hydroxylated polybrominated diphenyl ethers (OH-PBDEs), their methoxylated counterparts (MeO-PBDEs), and polybrominated dibenzo-p-dioxins (PBDDs), together with their potential precursors polybrominated phenols (PBPs) and polybrominated anisoles (PBAs), were analyzed in blue mussels (Mytilus edulis) gathered along the east coast (bordering the Baltic Sea) and west coast of Sweden (bordering the North Sea). Brown algae (Dictyosiphon foenicolaceus) and cyanobacteria (Nodularia spumigena) from the Baltic Sea, considered to be among the primary producers of these compounds, were also analyzed for comparison. MATERIALS AND METHODS: The samples were liquid-liquid extracted, separated into a phenolic and a neutral fraction, and subsequently analyzed by gas chromatography-mass spectrometry (GS-MS). RESULTS AND DISCUSSION: The levels of OH-PBDEs, MeO-PBDEs and PBDDs were significantly higher in Baltic Sea mussels than in those from the west coast, whereas the levels of PBPs and PBAs displayed the opposite pattern. The blue mussels from the Baltic Sea contained high levels of all analyzed substances, much higher than the levels of, e.g., polybrominated diphenyl ethers. In addition, the GC-MS chromatogram of the phenolic fraction of the west coast samples was dominated by four unknown peak clusters, three of which were tentatively identified as dihydroxy-PBDEs and the other as a hydroxylated-methyl-tetraBDE. CONCLUSIONS: Clearly, all of the compounds analyzed are natural products, both in the Baltic and the North Sea. However, the geographical differences in composition may indicate different origin, e.g., due to differences in the occurrence and/or abundance of various algae species along these two coasts or possibly a more extensive dilution on the west coast.

Organochlorine compounds and their metabolites in seven Icelandic seabird species - a comparative study.

The present study is designed to assess the occurrence of a few organochlorine contaminants and their metabolites in eggs of different marine bird species in Iceland, a country located in the sub-Arctic of the North-Western Atlantic. Previous investigations from e.g. Sweden and The Netherlands have shown some obvious differences in contaminant concentrations, including e.g. hydroxylated polychlorinated biphenyl metabolites (OH-PCBs) in guillemot (Uria aalge) and other bird species. Eggs from seven marine bird species, Arctic tern (Sterna paradisaea), common eider (Somateria mollissima), guillemot, fulmar (Fulmarus glacialis), great black-backed gull (Larus marinus), lesser black-backed gull (Larus fuscus), and great skua (Stercorarius skua), that all breed in Iceland, were collected and analyzed for several persistent organic compounds and their metabolites. The contaminant levels varied between the species investigated. The highest concentrations were found in eggs from the great skua (18 and 23 microg/g l.w. of CB-153 and 4,4'-DDE, respectively). The concentration difference was generally 2 orders of magnitude higher in great skua for all organochlorine compounds analyzed with the exception of HCB. HCB did not vary as much between the seven species (ranging from 34 to 710 ng/g l.w). OH-PCB and MeSO(2)-PCB metabolites congener concentrations and patterns showed differences in metabolic capacity between bird species. Guillemot and great skua seem to distinguish themselves most from other species i.e. with the absence of 4-OH-CB187 and low relative levels of 4-OH-CB146 in guillemot and the low abundance of OH-PCBs in great skua.

Temporal variations of polybrominated dibenzo-p-dioxin and methoxylated diphenyl ether concentrations in fish revealing large differences in exposure and metabolic stability.

The concentrations of polybrominated dibenzo-p-dioxins (PBDDs) and polybrominated methoxylated diphenyl ethers (MeO-PBDEs) were investigated in perch (Perca fluviatilis) collected from a Baltic Sea background contaminated area between 1990 and 2005. No temporal trend was found, but large variations were observed - up to 5-fold and 160-fold differences in MeO-PBDE and PBDD concentrations, respectively - between consecutive years, suggesting that retention of these compounds, particularly the PBDDs, is limited. Examination of the congener profiles using principal component analysis (PCA) and correlation analysis indicated that MeO-PBDEs without adjacent substituents (6-MeO-BDE47) or with two adjacent substituents (2'-MeO-BDE68 and 6-MeO-BDE90) are retained more than MeO-PBDEs with three adjacent substituents (6-MeO-BDE85 and 6-MeO-BDE99) and that 1,3,6,8-tetraBDD and 1,3,7,9-tetraBDD are retained more than the other PBDDs which have vicinal hydrogen. Debromination could explain the limited retention of 6-MeO-PBDE85 and 6-MeO-BDE99 and the absence of 2-MeO-BDE123 and 6-MeO-BDE137, and cytochrome P-450 mediated oxidation could explain the limited retention of PBDDs containing vicinal hydrogen. The levels of organobromines, especially MeO-PBDEs, were found to covary with water conditions related to primary production, for example temperature, depth visibility, and inorganic nutrient concentrations, which also favor fish productivity. The results suggest natural production of MeO-PBDEs and PBDDs and imply that they fluctuate considerably over time, as do common marine toxins in fish. Thus, assessments of human and environmental risk should consider both the average and peak concentrations of these contaminants in marine biota.

Spatial trends of polyfluorinated compounds in guillemot (Uria aalge) eggs from North-Western Europe.

Polyfluorinated alkyl compounds (PFCs) are a group of chemicals of growing concern that have been detected in biological and abiotic samples worldwide. This study reports the concentrations of a suite of PFCs: perfluorooctyl sulfonate (PFOS), perfluorooctyl sulfonamide (PFOSA) and perfluorinated carboxylic acids (PFCAs) in guillemot (Uria aalge) eggs, collected in North-Western Europe, from Iceland, the Faroe Islands, Sweden and two locations in Norway. The highest concentrations of PFOS were found in samples from Sweden (mean 400 ng g(-1) wet weight (w.w.)), which were almost five times higher than concentrations found in Norwegian samples (mean 85 ng g(-1)w.w. from both sample sites). The concentrations found in Icelandic and Faroe samples were lowest (mean 16 and 15 ng g(-1)w.w., respectively). Only Swedish samples differed significantly from the other locations. In general, PFCAs show a different spatial trend than PFOS. Perfluorooctanoic acid (PFOA) was not detected in any sample and perfluorononanoic acid (PFNA) was only detected in samples from Sweden. The most abundant PFCA was perfluoroundecanoic acid (PFUA) with highest concentrations in samples from Sweden (mean 82 ng g(-1)w.w.), samples from the Faroe Islands had the second highest concentration (mean 57 ng g(-1)w.w.) and samples from Iceland and Norway had concentrations ranging between 18 and 30 ng g(-1)w.w. The original hypothesis was based on the idea that PFC concentrations are the highest close to more densely populated and industrialized areas and lower levels in remote areas. However, the geographic pattern is more complicated than predicted and varies among different PFCs.