Combined microwave-assisted extraction and gel permeation chromatography for the determination of chlorinated hydrocarbons in seal blubber and cod livers

Persistent Organic Pollutants in Food: Contamination Sources, Health Effects and Detection Methods

Persistent organic pollutants (POPs) present in foods have been a major concern for food safety due to their persistence and toxic effects. To ensure food safety and protect human health from POPs, it is critical to achieve a better understanding of POP pathways into food and develop strategies to reduce human exposure. POPs could present in food in the raw stages, transferred from the environment or artificially introduced during food preparation steps. Exposure to these pollutants may cause various health problems such as endocrine disruption, cardiovascular diseases, cancers, diabetes, birth defects, and dysfunctional immune and reproductive systems. This review describes potential sources of POP food contamination, analytical approaches to measure POP levels in food and efforts to control food contamination with POPs.

High levels of medium-chain chlorinated paraffins and polybrominated diphenyl ethers on the inside of several household baking oven doors

Fat obtained by wipe tests on the inner surface of 21 baking ovens from Stuttgart (Germany) were analyzed for halogenated flame retardants (HFRs), namely polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE), dechlorane plus (DP), short- and medium-chain chlorinated paraffins (SCCPs, MCCPs), as well as polychlorinated biphenyls (PCBs). In ~50% of the samples chlorinated paraffins (CPs) were present in the mg/g fat range, i.e. three to four orders of magnitude higher concentrated than the sum of all other target compounds. In contrast the remaining ~50% of the samples were free of CPs, while the other HFRs were comparable in CP-positive and CP-negative samples. The exceptionally high concentrations and exclusive presence of CPs in half of the samples produced strong evidence that these compounds were released from the baking oven itself. This hypothesis was supported by detection of MCCPs at even higher concentrations in the inner components of one dismantled baking oven. The release of substantial amounts of HFRs from the oven casing during its use may contribute to human exposure to these compounds, especially MCCPs and SCCPs.

Polyhalogenated compounds (chlorinated paraffins, novel and classic flame retardants, POPs) in dishcloths after their regular use in households

Dishcloths are routinely used in the clean-up process following daily kitchen activities and are thus subject to contamination commensurate with their frequent use. Here we analyzed dishcloths for the occurrence of polyhalogenated compounds after 14days of use in household kitchens. Analysis of 19 dishcloths revealed the presence of 29 polyhalogenated contaminants with total mean/median concentrations of 6,900/3,600ng/dishcloth, respectively. The spectrum featured classic and novel halogenated flame-retardants (HFRs) like polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), decabromodiphenyl ethane (DBDPE), pentabromoethylbenzene (PBEB), chlordene plus and dechlorane plus, as well as typical chloropesticides and background contaminants (e.g. hexachlorobenzene (HCB), p,p'-dichlorodiphenyldichloroethene (p,p'-DDE), polychlorinated biphenyls (PCBs) and lindane). The individual dishcloths showed highly variable fingerprints of polyhalogenated compounds. If present, medium-chain chlorinated paraffins (MCCPs) were by far the most prominent compound class with up to 55,400ng/dishcloth. Without consideration of chlorinated paraffins, the mean concentration of other polychlorinated compounds (270ng/dishcloth) was generally one order of magnitude lower than the mean concentration of brominated flame retardants (BFRs) (1,700ng/dishcloth). Our study verified that a wide range of polyhalogenated compounds is readily available in the kitchen environment. Furthermore, dishcloths are ordinarily handled without gloves or hand protection, given the observed concentrations of polyhalogenated compounds in dishcloths, such handling may serve as an additional exposure pathway for human users. Evaluation of this thesis was supported by conduction of a dermal uptake assessment.

Analysis and Characterization of Polychlorinated Hydroxybornanes as Metabolites of Toxaphene Using a Polar Bear Model

Abiotic and biotic transformation of toxaphene (camphechlor) results in the selective enrichment of recalcitrant congeners while other, less persistent compounds of technical toxaphene (CTTs) are degraded. Until now, there has been little knowledge on oxidation transformation of toxaphene. For instance, the existence of hydroxylated CTTs (OH-CTTs) in authentic environmental and food samples has not been proven. For this reason, we synthesized a mixture consisting of tetra- to heptachlorinated OH-CTTs and simplified it by countercurrent chromatography (CCC). Thus, 227 OH-CTTs were detected in the CCC fractions (12 tetra-, 117 penta-, 81 hexa-, and 17 heptachlorinated OH-CTTs), which was >50% more than detected before the fractionation. One CCC fraction consisting of only 18 OH-CTTs was used to develop a sample cleanup method which aimed to remove CTTs, isobaric PCBs, and sample matrix. The final cleanup procedure consisted of (i) gel permeation chromatography (GPC) and adsorption chromatography using (ii) deactivated and (iii) activated silica gel. Hence, up to 320 and 4350 μg/kg lipid weight of octa- and nonachlorinated CTTs were detected in four liver samples and adipose tissue of polar bears, respectively. Furthermore, the presence of one hexachlorinated OH-CTT isomer could be verified in the samples, which was about 1% of the octachlorinated CTTs determined in the liver samples.

Modified Lipid Extraction Methods for Deep Subsurface Shale

Growing interest in the utilization of black shales for hydrocarbon development and environmental applications has spurred investigations of microbial functional diversity in the deep subsurface shale ecosystem. Lipid biomarker analyses including phospholipid fatty acids (PLFAs) and diglyceride fatty acids (DGFAs) represent sensitive tools for estimating biomass and characterizing the diversity of microbial communities. However, complex shale matrix properties create immense challenges for microbial lipid extraction procedures. Here, we test three different lipid extraction methods: modified Bligh and Dyer (mBD), Folch (FOL), and microwave assisted extraction (MAE), to examine their ability in the recovery and reproducibility of lipid biomarkers in deeply buried shales. The lipid biomarkers were analyzed as fatty acid methyl esters (FAMEs) with the GC-MS, and the average PL-FAME yield ranged from 67 to 400 pmol/g, while the average DG-FAME yield ranged from 600 to 3,000 pmol/g. The biomarker yields in the intact phospholipid Bligh and Dyer treatment (mBD + Phos + POPC), the Folch, the Bligh and Dyer citrate buffer (mBD-Cit), and the MAE treatments were all relatively higher and statistically similar compared to the other extraction treatments for both PLFAs and DGFAs. The biomarker yields were however highly variable within replicates for most extraction treatments, although the mBD + Phos + POPC treatment had relatively better reproducibility in the consistent fatty acid profiles. This variability across treatments which is associated with the highly complex nature of deeply buried shale matrix, further necessitates customized methodological developments for the improvement of lipid biomarker recovery.

Optimized Multiresidue Analysis of Organic Contaminants of Priority Concern in a Daily Consumed Fish (Grass Carp)

The organic contaminants, including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs), are of priority concern because of their persistence, toxicity, and long-distance transportation in global environment. Their residues in a daily consumed fish (grass carp) pose potential threat to human health and aquatic ecosystems. The present study optimized an analytical protocol of microwave-assisted extraction (MAE), lip-removal by gel permeation chromatography (GPC), cleanup by solid phase cartridge (SC) or adsorption chromatography column (CC), and gas chromatography-mass spectrometry (GC/MS). Besides traditional statistical parameters, some indicators were calculated to judge the performances of extraction by various methods. The optimization experiment showed that n-hexane/acetone was the best MEA extraction solvent; an optimal fraction time of 10-39 min could simultaneously elute all the target chemicals in a single GPC run. Both CC and SC showed good recoveries. However, CC performed better than SC (p < 0.05) for OCPs, and SC performed better than CC for PBDEs (p < 0.05). We also emphasized the limitations and advantages of SC and CC and finally proposed SC as the promising cleanup method because of its low-cost materials, time-saving steps, being free of manual filling, and operation by automated SPE system.

QuEChERS extraction for multi-residue analysis of PCBs, PAHs, PBDEs and PCDD/Fs in biological samples

In this study, a fast and rugged method is presented for the analysis of PCBs, PAHs, PBDEs and PCDD/Fs in biological tissues using a simple Quick, Easy, Cheap, Efficient, Rugged and Safe (QuEChERS) extraction and a clean-up by Gel Permeation Chromatography (GPC) and silica Solid Phase Extraction (SPE). Development was performed on blue mussels (Mytilus edulis) and Atlantic salmon (Salmo salar) for evaluation of two ranges of lipid and water content of biological tissues. Statistical validation was performed with Atlantic salmon samples. Forty-five PAHs were analyzed including the priority list of the US EPA and the European Union with 41 PCBs, 24 PBDEs and 17 PCDD/Fs. Instrumental analyses were performed on Gas Chromatography - High Resolution Mass Spectrometry (GC-HRMS). Accuracy was evaluated for PCBs and PCDD/Fs with a certified reference material furnished by the National Research Council Canada (NRCC) and also compared with results obtained by the conventional Soxhlet extraction. Statistical validation showed recoveries for PCBs, PAHs, PBDEs and PCDD/Fs close to 100% with average Relative Standard Deviation (RSD) lower than 10% and internal standard recoveries in the range of 70% with average RSD ranging from 5-15%. Average calculated Method Detection Limits (MDLs) were lower than 0.05μg/Kg for PCBs, 0.2μg/Kg for PAHs and PBDEs and 1ng/Kg for PCDD/Fs. The method is a faster and cheaper alternative to the time-consuming conventional method that has been used in most environmental laboratories.

Polyhalogenated compounds (PCBs, chlordanes, HCB and BFRs) in four polar bears (Ursus maritimus) that swam malnourished from East Greenland to Iceland

Levels of organohalogen compounds (PCBs, chlordane, PBB 153, PBDEs, HCB) were determined in adipose tissue, liver, kidney and muscle of four polar bears which swam and/or drifted to Iceland in extremely malnourished condition. Since the colonization in the 9th century polar bears have been repeatedly observed in Iceland. However, in recent years three of the animals have clearly left their natural habitat in poor condition in May or June, i.e. at the end of the major feeding season. The fourth bear is believed to have drifted with melting ice to North-Eastern Iceland in mid-winter. The concentrations of the POPs were within the range or higher than the typical concentrations measured in polar bears from the East Greenland population. In addition to the targeted compounds, we tentatively detected Dechlorane 602 and its potential hydrodechlorinated Cl11-metabolite in all samples. Moreover, a polychlorinated compound which partly co-eluted with PCB 209 was detected in all liver samples but not in adipose tissue, kidney or muscle. The mass spectrum of the potential metabolite did not allow determining its structure. Polar bears are good swimmers and can reach Iceland from the ice edge of East Greenland within a few days. Potential reasons for the swims are briefly discussed.

Validation of high-throughput measurement system with microwave-assisted extraction, fully automated sample preparation device, and gas chromatography-electron capture detector for determination of polychlorinated biphenyls in whale blubber

Validation of a high-throughput measurement system with microwave-assisted extraction (MAE), fully automated sample preparation device (SPD), and gas chromatography-electron capture detector (GC-ECD) for the determination of polychlorinated biphenyls (PCBs) in minke whale blubber was performed. PCB congeners accounting for > 95% of the total PCBs burden in blubber were efficiently extracted with a small volume (20 mL) of n-hexane using MAE due to simultaneous saponification and extraction. Further, the crude extract obtained by MAE was rapidly purified and automatically substituted to a small volume (1 mL) of toluene using SPD without using concentrators. Furthermore, the concentration of PCBs in the purified and concentrated solution was accurately determined by GC-ECD. Moreover, the result of accuracy test using a certified material (SRM 1588b; Cod liver oil) showed good agreement with the NIST certified concentration values. In addition, the method quantification limit of total-PCB in whale blubbers was 41 ng g(-1). This new measurement system for PCBs takes only four hours. Consequently, it indicated this method is the most suitable for the monitoring and screening of PCBs in the conservation of the marine ecosystem and safe distribution of foods.

Comparison of five extraction methods for measuring PCBs, PBDEs, organochlorine pesticides, and lipid content in serum

An increasing number of studies use blood obtained noninvasively to monitor organohalogen contaminants; however, blood can be difficult to analyze because of its aqueous nature and high protein content. We compared five methods for extracting polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), organochlorine pesticides, and lipids from serum using National Institute of Standards and Technology Standard Reference Material 1589a PCBs, Pesticides, PBDEs, and Dioxins/Furans in Human Serum. Liquid:liquid (LLE), cavity-dispersed microwave-assisted (MAE), focused microwave-assisted (FME), solid-phase (SPE), and pressurized fluid (PFE) extraction techniques were compared. FME extraction yielded the optimal recovery of internal standards (IS). All methods resulted in similar contaminant concentrations that also agreed with the certified values for SRM 1589a, except for only a few compounds measured by methods other than FME. Based on these findings, the FME method was determined to be the best overall extraction method. One procedural factor was found to affect contaminant concentrations; use of IS carrier solvents that were immiscible with serum (or when the serum was not directly physically mixed with IS) resulted in a 30% underestimation of organohalogen concentrations. This study offers valid, novel extraction alternatives beyond traditional methods (e.g., LLE) for blood contaminant measurements.

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.

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.

Advances in the environmental analysis of polychlorinated naphthalenes and toxaphene

Recent advances in the analysis of the chlorinated environmental pollutants polychlorinated naphthalenes (PCNs) and toxaphene are highlighted in this review. Method improvements have been realized for PCNs over the past decade in isomer-specific quantification, peak resolution, and the availability of mass-labeled standards. Toxaphene method advancements include the application of new capillary gas chromatographic (GC) stationary phases, mass spectrometry (MS), especially ion trap MS, and the availability of Standard Reference Materials that are value-assigned for total toxaphene and selected congener concentrations. An area of promise for the separation of complex mixtures such as PCNs and toxaphene is the development of multidimensional GC techniques. The need for continued advancements and efficiencies in the analysis of contaminants such as PCNs and toxaphene remains as monitoring requirements for these compound classes are established under international agreements.

Rapid method for the determination of 16 organochlorine pesticides in sesame seeds by microwave-assisted extraction and analysis of extracts by gas chromatography–mass spectrometry

A method for the multiresidue analysis of 16 organochlorine insecticides in sesame seeds has been developed. The method is based on the microwave-assisted extraction (MAE) of the sesame seeds by the use of a water-acetonitrile mixture followed by Florisil clean-up of the extracts and subsequent analysis by gas chromatography-mass spectrometry (GC/MS) in the selected ion monitoring (SIM) mode. MAE operational parameters (extraction solvent, temperature and time, extractant volume) were optimized with respect to extraction efficiency of the target compounds from sesame seeds with 46% oil content. Recoveries >80% with relative standard deviations (RSD) <12% were obtained for all compounds under the selected parameters. The Florisil clean-up step proved sufficient for the removal of co-extracted substances so that no adverse effect on the chromatographic system was observed. Limit of quantification (LOQ) values were in the range of 5-10 microg/kg. The proposed method was applied in the analysis of sesame seed samples imported to Greece.

Application of matrix solid-phase dispersion to the determination of polychlorinated biphenyls in fat by gas chromatography with electron-capture and mass spectrometric detection

A one-step extraction-purification method for the determination of polychlorinated biphenyls (CBs) in fat samples was developed. Matrix solid-phase dispersion using different combinations of normal phase sorbents and elution solvents was evaluated, in terms of extraction yield and lipids removal efficiency, for the isolation of CBs from butter, chicken and beef fat. Under optimal conditions, 0.5 g of sample was dried with anhydrous sodium sulphate, dispersed on 1.5 g of Florisil and transferred to the top of a polyethylene solid-phase extraction cartridge which already contain 5 g of Florisil. Non-coplanar CBs were quantitatively eluted with 15 ml of n-hexane. The lipid percentage in this extract remained below 0.06% of the sample mass. As coplanar congeners show a higher affinity for Florisil, 20 ml of hexane-dichloromethane (90:10) were necessary for the quantitative recovery of coplanar and non-coplanar CBs. The potential of the procedure to fractionate non-coplanar and coplanar congeners is discussed. After extract evaporation to 0.2 ml, quantification limits of 0.4 ng of each CB per g of fat were achieved, using gas chromatography with tandem MS or electron-capture detection (ECD).

Determination of polybrominated diphenyl ethers in marine biological tissues using microwave-assisted extraction

Growing concern on the environmental impact of polybrominated diphenyl ethers (PBDEs) has created the need for rapid and quality assured analytical methods to quantify PBDEs in a spectrum of matrix types. This study presents the first validated method for the quantification of major PBDE congeners (47, 99 and 100) in marine biological tissues using microwave-assisted extraction (MAE). The recovery of polychlorinated biphenyls and various organochlorine pesticides has also been ascertained. Analytical accuracy, precision, limits of detection and cleanup efficiency were evaluated for PBDE congeners, and empirical data justifies the use of MAE for the extraction and analysis of PBDEs in biological matrices. MAE was also compared to Soxhlet extraction efficiency for PBDEs in the standard reference materials SRM2978 and SRM1588a and gave comparable results (<15% variation).

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

Several identified and potential natural brominated bioaccumulative compounds were studied in this work. 4,6-dibromo-2-(2('),4(')-dibromo)phenoxyanisole (BC-2) previously detected in Australian marine mammals and isolated from sponges, was synthesized. Two byproducts (a tetrabromo isomer and a tribromo congener) were investigated as well. The byproducts of the synthesis were not identified in the environmental samples investigated. Previously described natural brominated compounds (BC-1, BC-2, BC-3, BC-10, BC-11, MHC-1) and anthropogenic brominated diphenyl ethers (BDE-47, BDE-99, BDE-100, BDE-154) were detected in a sample of human milk. The sample was from a woman from the Faeroe Islands who frequently consumed fish as well as whale blubber and meat. The most abundant compound originated from the natural tetrabromo phenoxyanisole BC-3 which may have a 3:1 distribution of bromine on the two phenyl units. This sample also accumulated a dibromochloroanisole, as well as a previously unknown mixed halogenated compound (MHC-X) and an unknown, most likely aromatic brominated compound. Co-elutions on a DB-5 column were found for BDE-99 and BC-11 as well as BDE-154 and the unknown brominated compound. This suggests that quantification of these two compounds has to be carried out carefully.Two samples of lower trophic level, namely Baltic cod liver and Mexican mussel tissue, were investigated as well. The cod liver samples contained BDE congeners but also abundant signals for the natural 2,3,3('),4,4('),5,5(')-heptachloro-1(')-methyl-1,2(')-bipyrrole Q1 and tribromoanisole (TBA). The mussel sample contained Q1, TBA, another halogenated anisole, BC-1, BC-2, and BC-3, as well as additional, potential natural brominated compounds in the elution range of tribromophenoxyanisoles.

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.

Recent applications of sample preparation techniques in food analysis

Even with the emergence of advanced techniques of separation and identification, it is rarely possible to analyse food without manipulation. The traditional techniques for sample preparation are time consuming and require large amount of reagents, which are expensive, generate considerable waste, contaminate the sample and can enrich it for analytes. The more analytical techniques have become highly developed, the more has sample clean-up become important in order to fully take advantage of them. Due to the multiplicity of food matrices, it is not possible to use one sample preparation technique, so many methods have been proposed for meeting all the requirements. The newest variations of wet digestion, solvent and sorbent extraction and membrane separation are summarised and their most recent applications to food analysis are provided.

Sponge halogenated natural products found at parts-per-million levels in marine mammals

Several unknown, abundant brominated compounds (BCs) were recently detected in the blubber of dolphins and other marine mammals from Queensland (northeast Australia). The BCs were interpreted as potential natural products due to the lack of anthropogenic sources for these compounds. This study investigated whether some of the BCs accumulated by diverse marine mammal species are identical with natural BCs previously isolated from sponges (Dysidea sp.) living in the same habitat. Isolates from sponges and mollusks (Asteronotus cespitosus) were compared with the signals detected in the mammals' tissue. Mass spectra and gas chromatography retention times on four different capillary columns of the isolates from sponges and mammals were identical in all respects. This proves that the chemical name of the compound previously labeled BC-2 is 4,6-dibromo-2-(2',4'-dibromo)phenoxyanisole and that the chemical name of BC-11 is 3,5-dibromo-2-(3',5'-dibromo,2'-methoxy)phenoxyanisole. Using a quantitative reference solution of BC-2, we established that the concentrations of the brominated metabolites found in the marine mammals are frequently >1 mg/kg. The highest concentration (3.8 mg/kg), found in a sample of pygmy sperm whale (Kogia breviceps), indicates that BC-2 is a bioaccumulative, natural organohalogen compound. This is supported by the concentrations of the BCs in our samples being equal to the highest concentrations of anthropogenic BCs in any environmental sample. The quantitative determination of BC-2 in blubber of marine mammals from Africa and the Antarctic suggests that BC-2 is widespread. These results are direct proof that marine biota can produce persistent organic chemicals that accumulate to substantial concentrations in higher trophic organisms.

Environmental occurrence of Q1, a C9H3C17N2 compound, that has been identified as a natural bioaccumulative organochlorine

Environmental appearance of Q1, a natural heptachloro compound with the molecular formula C9H3C17N2, was studied in samples from different sites all over the world. Q1 was expected to have a bipyrrole backbone, similar to other compounds ascribed to natural sources. A method for isolation of Q1 was developed by combination of adsorption chromatography on silica and normal phase HPLC with an amino phase. UV-detection of Q1 supports the aromatic character of the compound. The high levels detected in samples of marine mammals and birds suggested that Q1 is both a persistent and a bioaccumulative contaminant. This was underscored by calculated logK(ow) in the range of other lipophilic organohalogens. In accordance with earlier studies, highest Ql concentrations were found in the Southern Hemisphere, but with a highly selective GC/ECNI-MS-SIM method, detection of Q1 was also achieved in many samples from the Northern Hemisphere. In addition to marine mammals and birds. Q1 was also detected in fish from the Mediterranean Sea and the Antarctic. Traces were also detected in SRM 1588 certified cod liver oil, but Q1 was not detected in fish from Hong Kong and Lake Baikal.

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.

Structure of a persistent heptachlorobornane in toxaphene (b7-1000) agrees with molecular model predictions

A Cl(7) component of technical toxaphene (CTT), previously detected in marine mammals and fish and referred to as "7-1", was isolated from contaminated estuarine sediment using preparative solid-liquid chromatography followed by reversed-phase HPLC. The structure of this compound, elucidated by GC/MS and (1)H NMR, was 2-endo,3-exo,5-endo,6-exo,8,8,10-heptachlorobornane (hereafter referred to as B7-1000). This newly identified CTT eluted in the nonpolar fraction from silica and shares the alternating endo-exo chlorine substitution pattern with other relatively nonpolar, persistent congeners (e.g., B8-1413 and B9-1679). Based on ECNI-MS response, levels of B7-1000 in tissue samples of various higher organisms including humans were as high as 16% of B8-1413. Enantioselective determination of B7-1000 using a modified cyclodextrin chiral stationary phase (beta-BSCD) resulted in enantiomer ratios that were depleted in adipose tissue of a marine bird (skua) and Weddell seal blubber (0.3 and 0.5, respectively), but not in elephant seal blubber (1.1). Elucidation of the structure of B7-1000 thus validates previous predictions of persistence based on structure-activity relationships, chromatographic properties, and molecular modeling.

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.