Natural and man-made organobromine compounds in marine biota from Central Norway

Brominated organic pollutants were found in selected samples of mollusk tissue, fish liver, as well as in the eggs and livers of shag from three sites in Central Norway. More than 80 organobromines were identified owing to the defined isotope ratio acquired by GC/ECNI-MS. However, only a few peaks could be assigned to anthropogenic brominated flame retardants (polybrominated diphenyl ethers). Most of the organobromine compounds detected were unknown or halogenated natural products. The known halogenated natural products MHC-1 and TBA were abundant in all samples and usually between equally abundant, and up to 50 fold more concentrated than the major polybrominated diphenyl ether congener BDE 47. The halogenated natural products BC-2 (2-MeO-BDE 68) and BC-3 (6'-MeO-BDE 47), were on level with BDE 100 which was the second most abundant BDE congener in many samples. The previously identified natural polybrominated hexahydroxanthene derivatives (PBHDs) were detected for the first time in bird eggs. Being major contaminants in bird eggs, PBHDs were only present at low levels in bird liver from nestlings originating from the same clutch. Such differences were detected for several other major contaminants. One unknown tetrabromo compound particularly abundant in mussels from Munkholmen was studied by GC/MS and the molecular ion was detected at m/z 446. The abundance of the most important unknown compounds did not correlate with BDEs and they most likely represent halogenated natural products. This study supports that halogenated natural products have to be treated as serious contaminants of marine coastal waters. Our data suggest that their abundance is highest in habitats along the shoreline. Thorough examination of these compounds in environmental samples is an important task.     

Biomagnification of anthropogenic and naturally-produced organobrominated compounds in a marine food web from Sydney Harbour, Australia

Polybrominated diphenyl ethers (PBDEs) and naturally-produced organobrominated compounds, such as methoxylated PBDEs (MeO-PBDEs), have been scarcely studied in the Southern Hemisphere. Yet, sources of the latter group of compounds were found in Southern regions, specifically in Australia. The environmental distribution and biomagnification potential of organobrominated compounds were therefore investigated in a representative aquatic food chain (invertebrates and fish) from the Sydney Harbour, Australia. Mean PBDE concentrations ranged from 6.4 ng/g lipid weight (lw) in squid to 115 ng/g lw in flounder. BDE 47 was the dominant congener, followed by BDE 100. Mean levels of MeO-PBDEs (sum of congeners 2’-MeO-BDE 68 and 6-MeO-BDE 47) were as high as 110 ng/g lw in tailor, with a slight dominance of 2’-MeO-BDE 68. Polybrominated hexahydroxanthene derivates (PBHDs), another class of naturally-produced compounds, were found at variable concentrations and ranged from 4.7 ng/g lw in fanbelly and 146 ng/g lw in tailor. The tribrominated PBHD isomer dominated in the samples, except for luderick and squid. The lower levels of PBDEs found in luderick from the harbour compared to those obtained from the upper Parramatta River indicated a terrestrial (anthropogenic) origin of PBDEs, while the higher levels of MeO-PBDEs and PBHDs in the samples from the harbour confirmed the marine (natural) origin of these compounds. The highest trophic magnification factor (TMF) was found for sum PBDEs (3.9), while TMFs for sum MeO-PBDEs and sum PBHDs were 2.9 and 3.4, respectively. This suggests that biomagnification occurs in the studied aquatic food chain for anthropogenic brominated compounds, but also for the naturally-produced organobromines.     

Sulfide tolerance and detoxification in shallow-water marine fishes

Hydrogen sulfide is a potent inhibitor of aerobic respiration. Sulfide is produced in sediments, and many species of fish live in association with the bottom. Tolerance tests, enzyme assays, and chromatography of sulfur compounds in thirteen species of shallow-water marine fishes (collected in San Diego, California, USA in 1987–1988) indicate adaptations to sulfide that vary with habitat and lifestyle. Tidal-marsh inhabitants, like Gillichthys mirabilis and Fundulus parvipinnis, have higher tolerance to sulfide (96 h LC₅₀ at 525 to 700 M) relative to outer-bay and open-coast inhabitants (surviving <12 h at much lower concentrations). The cytochrome c oxidase of all species shows high activity and susceptibility to sulfide poisoning, with 50% inhibition at 30 to 500 nM in various tissues. The two marsh species are able to survive at sulfide concentrations already inhibitory to their cytochrome c oxidase and fatal to other species. All species detoxify sulfide by oxidizing it to thiosulfate. All have sulfide-oxidizing activity in the blood, spleen, kidney, liver and gills, which correlates significantly with heme content. Thiosulfate appears in the tissues of sulfide-exposed fish and builds up to high concentrations (up to 2 mM) with stronger and longer exposure. Unexposed fish contain little or no thiosulfate. Sulfide is barely detectable in the tissues, even in high-sulfide exposure tests. We suggest that fish blood, in having high sulfide-oxidizing activity and no cytochrome c oxidase, can act as a short-term first line of defense against sulfide, and thus minimize the amount that reaches the vital organs. The results of this study indicate that sulfide is a significant environmental factor influencing the ecological distribution of marine fishes.     

Determination of Q1, an unknown organochlorine contaminant, in human milk, Antarctic air, and further environmental samples

Q1, an organochlorine component with the molecular formula C(9)H(3)Cl(7)N(2) and of unknown origin was recently identified in seal blubber samples from the Namibian coast (southwest of Africa) and the Antarctic. In these samples, Q1 was more abundant than PCBs and on the level of DDT residues. Furthermore, Q1 was more abundant in seals from the Antarctic than the Arctic. To prove this assumption, gas chromatography-electron-capture negative ion mass spectrometry (GC/ECNI-MS), which is sensitive and selective for Q1, allowed for screening of traces of Q1 even in samples with particularly high levels of other organochlorine contaminants. Q1 was isolated by high-performance liquid chromatography (HPLC) from a skua liver sample. A 1:1 mixture with trans-nonachlor in electron-capture detectors (ECDs) was used to determine the relative response factor with ECNI-MS. The ECNI-MS response of Q1 turned out to be 4.5 times higher than that of trans-nonachlor in an ECD. With GC/ECNI-MS in the selected ion-monitoring mode, four Antarctic and four Arctic air samples were investigated for the presence of Q1. In the Antarctic air samples, Q1 levels ranged from 0.7 to 0.9 fg/m(3). In Arctic air samples, however, Q1 was below the detection limit (<0.06 fg/m(3) or 60 ag/m(3)). We also report on high Q1 levels in selected human milk samples (12-230 microg/kg lipid) and, therefore, suggested that the unknown Q1 is an environmental compound whose origin and distribution should be investigated in detail. Our data confirm that Q1 is a bioaccumulative natural organochlorine product. Detection of a highly chlorinated natural organochlorine compound in air and human milk is novel.     

Monobromo and higher brominated congeners of the marine halogenated natural product 2,3,3',4,4',5,5'-heptachloro-1'-methyl-1,2'-bipyrrole (Q1)

The marine halogenated natural product 2,3,3',4,4',5,5'-heptachloro-1'-methyl-1,2'-bipyrrole (Q1) is widely distributed in the environment. In this study, we screened samples which have previously been found to contain remarkably high residues of Q1 (blubber of marine mammals from Australia, samples from Antarctica, human milk from the Faroe Island) for the additional presence of mixed chlorinated and brominated congeners. Using GC/ECNI-MS, all samples tested were positive and many contained four out of five possible bromohexachloro congeners (BrCl6-MBPs), five out of 14 possible dibromopentachloro congeners (Br2Cl5-MBPs), five of 21 possible tribromotetrachloro-congeners (Br3Cl4-MBPs), as well as several higher brominated congeners. About 20 heptahalo congeners of Q1 are described for the first time in the scientific literature. Isomers eluted within about one minute, respectively. Hence it is possible, that the peak clusters identified may be composed of more, co-eluting congeners. Similarities in the GC/ECNI-MS mass spectra with polychlorinated biphenyls (PCBs) were addressed. We also suggest an acronym system similar to that in use for polychlorinated biphenyls that may simplify the use of this substance class in scientific papers. In the samples from Australia, BrCl6-MBPs and Br2Cl5-MBPs amounted for 7-27.5% and 0.4-4.2% of Q1, respectively whereas Br3Cl4-MBPs and higher brominated MBPs were found in the range of <1% of Q1 or less.     

Brominated flame retardants and other organobromines in Norwegian predatory bird eggs

A set of 62 unhatched eggs was collected from six different predatory bird species throughout Norway after incubation period was completed. They were analysed for PBDE, PBB, TBBP A and naturally occurring halogenated compounds. BDE 47, 99 and 153 were the dominating congeners, with species dependent PBDE patterns. BDE 153 was observed as the most abundant congener in eggs of peregrine falcon, golden eagle and merlin. The highest PBDE level (sum of nine congeners) was found in eggs of white-tailed sea eagle with up to 800ng/gww (median sumPBDE: 184ng/gww), followed by eggs of peregrine falcon and osprey (median sumPBDE: 155 and 105ng/gww, respectively). Golden eagle eggs showed the lowest concentration of all species (median sumPBDE: 3ng/gww). The levels in the peregrine falcon are similar to those found earlier in the Baltic region [Lindberg, P., Sellstrom, U., Haggberg, L., de Wit, C.A., 2004. Higher brominated diphenyl ethers and hexabromocyclododecane found in eggs of peregrine falcons (Falco peregrinus) breeding in Sweden. Environmental Science & Technology. 38 (1), 93-96]. The differences between species are not fully explainable, due to lack of data from the major food species. BB 101 and 153 were found in eggs of all investigated bird species. Especially in samples of white-tailed sea eagle, peregrine falcon and goshawk additional unknown penta- and hexabrominated biphenyls were detected. TBBP A was detected in all of eight eggs analysed sampled from four different bird of prey species. The naturally occurring halogenated compounds Q1, the dibromotrichloro monoterpene MHC-1, and 2,4,6-tribromoanisole (TBA) were detected in all of seven analysed samples except for one peregrine falcon egg.     

Distribution and levels of eight toxaphene congeners in different tissues of marine mammals, birds and cod livers

Levels and distribution of eight compounds of technical toxaphene (CTTs) were determined in different marine species (seals, cetaceans, birds, and fish). The eight CTTs included six commercially available and two chlorobornanes prepared in our lab. These congeners were present in all investigated samples. In agreement with earlier studies, the octachlorobornane B8-1413 (P-26) and the nonachlorobornane B9-1679 (P-50) were the most abundant congeners in most of the samples. In seal blubber, B8-1413 (P-26) and B9-1679 (P-50) contributed with up to approximately 80% (Weddell seal) to the sum of the eight CTTs. In seals from the northern hemisphere the nonachlorobornane was more abundant while in those from the southern hemisphere (Antarctic and Namibia), the octachlorobornane B8-1413 (P-26) usually appeared at higher concentrations. Depending on the species the contribution of the other congeners varied significantly. B9-1025 (P-62) ranged from 2-20%, B8-1412 was found at 4-25% with highest contribution in birds, and B8-2229 (P-44) was found at 5-15%. The remaining three congeners B7-1453, B8-1414 (P-40), and B8-1945 (P-41) were lower abundant except B8-1414 (P-40) which was found at high contribution in liver and kidney of birds. The sum of the eight CTTs ranged from 4 microg/kg to 1.4 mg/kg, depending on the species and region. In most of the seal blubber samples, PCBs and DDT were more abundant (factor 2-20) but Antarctic Weddell seals showed higher CTT levels than PCBs and DDT.     

Congener-specific concentrations and carbon stable isotope ratios (delta13C) of two technical toxaphene products (Toxaphene and Melipax)

In this study we compared the contribution of individual congeners and the ratios of stable carbon isotopes of two technical toxaphene products. The former US-American product Toxaphene was from 1978 and the East-German product Melipax from 1979. Both technical products showed the known complexity in GC/ECD measurements. Contributions of 24 peaks to each of the technical products were determined by gas chromatography in combination high resolution electron capture negative ion mass spectrometry (GC/ECNI-HRMS). The percentages of the compounds studied in the technical mixtures ranged from approximately 0.05% to approximately 2.5% but showed some individual differences. 2,2,5,5,8,9,9,10,10-nonachlorobornane (B9-1025 or P-62) was identified as a major congener in both mixtures. 2-Endo,3-exo,5-endo,6-exo,8,8,10,10-octachlorobornane (B8-1413 or P26) and 2-endo,3-exo,5-endo,6-exo,8,8,9,10,10-nonachlorobornane (B9-1679 or P-50) were found at similar concentration in both technical products. Identical amounts of Melipax or Toxaphene were combusted to CO2 in an element analyzer and their delta13C values were determined relative to the international standard Vienna PeeDee belemnite (VPDB). The mean delta13C values of both products varied by 2.8% (determined at two different locations) which is roughly one order of magnitude more than the precision obtained in repetitive analyses of the individual products. Thus, both investigated products could be unequivocally distinguished by stable isotope ratio mass spectrometry (IRMS). IRMS analyses may thus be a suitable tool for tracing back toxaphene residues in environmental and food samples to the one or both of the products.     

Enantioselective determination of persistent and partly degradable toxaphene congeners in high trophic level biota

Enantiomer separation of chiral toxaphene components in biological samples was studied by application of different chiral stationary phases based on modified cyclodextrins. Several pairs of enantiomers were resolved on permethylated beta-cyclodextrin (beta-PMCD), among them 2-endo,3-exo,5-endo,6-exo,8,8,9,10-octachlorobornane (B8-1412), which was not enantiomerically resolved on tert-butyldimethylsilylated beta-cyclodextrin (beta-BSCD). The latter column was applied to determine the enantiomer ratios (ERs) of 2-endo,3-exo,5-endo,6-exo,8,8,10,10-octachlorobornane (B8-1413 or P-26) in brain tissue of three seal species. The ER of B8-1413 (P-26) in brain was virtually racemic as well as those of the two persistent and chiral components of technical chlordane, 1-exo,2,2,4,5,6,7,8,8-octachloro-3a,4,7,7a-tetrahydro-4,7-metha noindane (trans-nonachlor III or MC 6) and 1-exo,2-endo,3-exo,4,5,6,8,8-octachloro-3a,7,7a-tetrahydro-4,7- methanoindane (U82). In contrast, B8-1412 and 2-exo,5,5,8,9,9,10,10-octachlorobornane (B8-2229 or P-44) were significantly enantiomerically enriched in several samples of high trophic level biota. 2,2,5,5,8,9,9,10,10-Nonachlorobornane (B9-1025 or P-62), a chlorobornane metabolisable by seals and the presumable precursor of B8-2229 (P-44), was also enantiomerically enriched in seal blubber. These results confirm the assumption that some less persistent toxaphene components may be significantly degraded in biological samples. Enantioselective gas chromatography provides the information that such a degradation is happening by the characteristic change of the ratio of the two enantiomers in the respective tissues.