Total Polychlorinated Naphthalenes Concentrations Research Articles

Polychlorinated naphthalene concentrations and temporal trends in serum from the general Chinese adult population and effects of polychlorinated naphthalenes on thyroid function

Polychlorinated naphthalenes (PCNs) have stopped being produced and used but have been detected in human serum around the world. Investigating temporal trends in PCN concentrations in human serum will improve our understanding of human exposure to PCNs and the risks posed. We determined the PCN concentrations in serum collected from 32 adults in five consecutive years (2012–2016). The total PCN concentrations in the serum samples were 0.00–5443 pg/g lipid weight. We found no significant decreases in the total PCN concentrations in human serum and even found that the concentrations of some PCN congeners (e.g., CN20) increased over time. We found differences in the PCN concentrations in serum from males and females, the CN75 concentration being significantly higher in serum from females than males, meaning CN75 poses more serious risks to females than males. We found, using molecular docking techniques, that CN75 interferes with thyroid hormone transport in vivo and that CN20 affects thyroid hormone binding to receptors. These two effects are synergistic and can cause hypothyroidism-like symptoms.

Polychlorinated naphthalenes (PCNs) in soils and plants from Svalbard, Arctic: Levels, distribution, and potential sources

As persistent organic pollutants (POPs) newly banned by the Stockholm Convention, polychlorinated naphthalenes (PCNs) have been widely detected in various environmental matrices. To date, however, the occurrence of PCNs in soils and plants in the Arctic environment has not been reported. In the current study, the concentrations and distribution of PCNs in Arctic soils and plants from Svalbard were analyzed. Total PCN concentrations ranged from 5.3 to 2550 pg/g dry weight (dw) in soils and 77 to 870 pg/g dw in plants. The higher levels of PCNs near the research stations and Longyearbyen town highlighted the significant influence of local anthropogenic emission sources. The composition of PCNs in Arctic soils and plants was dominated by lower chlorinated homologues, especially mono- to trichlorinated naphthalenes, which accounted for over 80 % of total PCNs in the soil and plant samples. The correlation analysis indicated the potential influences of total organic carbon (TOC) content on PCN concentrations in the soil, and octanol-air partition coefficients (KOA) or octanol-water partition coefficients (KOW) on PCN accumulation from soils to plants. To the best of our knowledge, this is the first study to report on the concentration and distribution of PCNs in Arctic soils and plants.

Polychlorinated naphthalenes in farmed Chinese mitten crabs in China: Concentration, distribution and source analysis

Polychlorinated naphthalenes (PCNs) are both highly toxic and bioaccumulative environmental contaminates. Dietary intake is the primary pathway for human exposure to PCNs, and PCN concentrations in aquatic foodstuffs are relatively high. Chinese mitten crab (Eriocheir sinensis) is one kind of popular aquatic foodstuffs in Asian countries. Farmed crabs could exposure to PCNs both through feed and environment. However, information on the occurrence of PCNs in farmed crabs is scarce. The present study investigated 75 PCN congeners in farmed Chinese mitten crabs, crab compound feed and sediments collected from Anhui Province and Shanghai in China. The total PCN concentrations in farmed Chinese mitten crabs from Anhui Province and Shanghai were 11.2–42.2 and 5.46–43.8 pg/g wet weight (ww), respectively. The PCN homologue profiles in crabs from both areas were similar, and both were dominated by di-CNs and penta-CNs. In contrast, lower chlorinated PCNs (di-CNs, tri-CNs and tetra-CNs) were the most common homologues in specimens of crab compound feed and sediment samples, indicating that selective bioaccumulation and metabolism of PCNs might occur in farmed crabs. No regional differences were found in the PCN congener profiles of farmed crabs, feed and sediment samples taken from Anhui Province and Shanghai. An assessment found no significant health risk associated with Chinese exposure to PCNs through farmed Chinese mitten crab consumption.

Partitioning and potential sources of polychlorinated naphthalenes in water-sediment system from the Yangtze River Delta, China

Spatial trends, partitioning behavior, and potential sources of polychlorinated naphthalenes (PCNs) in water-sediment system from the Yangtze River Delta (YRD) were investigated in this study. The total concentrations of 75 PCNs in water and sediment samples were 0.022–0.310 ng/L and 0.01–1.59 ng/g dry weight, respectively. The homolog patterns in the sediment and water samples were somewhat different. Di-to tetra-CNs made larger contributions in the sediment, while the mono-to tri-CNs were dominant homologs in the water. Overall, the low-chlorinated naphthalenes (mono-to tetra-CNs) were found to be the dominant homologs in the YRD water and sediment samples, and the homolog group contributions to the total PCNs concentrations decreased as the number of chlorine atoms increased. CN-5/7 and CN-24/14 were found at high concentrations in both the water and sediment. Partitioning and transfer of PCNs between water and sediment were assessed by calculating the partition coefficients and fugacity fractions. The partition coefficients showed that PCNs were not in equilibrium status in the water–sediment system, and hydrophobicity played an important role in PCNs partitioning. The fugacity fractions indicated that mono- to tri-CNs had stronger tendencies to escape from the sediment into the water, while the high-chlorinated naphthalenes close to equilibrium. Principal component analysis and correlation analysis indicated that industrial thermal processes and the use and disposal of products containing PCNs industrial products are sources of PCNs in the YRD water-sediment system.

Polychlorinated Naphthalenes across the Great Lakes: Lake Trout and Walleye Concentrations, Trends, and TEQ Assessment-2004-2018.

Polychlorinated naphthalenes (PCNs) were measured in lake trout and walleye over the period 2004-2018, utilizing isotope dilution techniques with high-resolution gas chromatography/high-resolution mass spectrometry to assess concentrations and toxic equivalence (TEQ). An age-trend model was applied to mitigate the effect of a changing lake trout age structure. Most Great Lakes Fish Monitoring and Surveillance Program sampling sites demonstrated significant half-life and percent decreases for lake trout total PCNs and total TEQ over the 2004-2018 period, the exceptions being Lake Erie lake trout and walleye which illustrated increasing concentrations. Great Lakes total PCN concentrations ranged between 5701 and 100 pg/g ww, whereas total PCN TEQ concentrations ranged between 8.89 and 0.13 pg-TEQ/g ww. Based on the average number of chlorines per naphthalene, we determined that the overall lake trout and walleye PCN congener distribution has significantly shifted to a lower-chlorinated composition in the Great Lakes (5.33 to 4.48 Cl/CN) and has resulted in a substantial 59.1% reduction of the overall total PCN TEQ burden. A prominent PCN concentration trend breakpoint was observed in Lake Ontario lake trout over the 2012-2016 period likely associated with hazardous waste cleanups, channel dredging, and spoils disposal in the Detroit River and western-basin of Lake Erie.

Atmospheric pressure ionization for gas chromatography-high resolution mass spectrometry determination of polychlorinated naphthalenes in marine sediments

In this work, the performance of the atmospheric pressure chemical ionization (APCI) and photoionization (APPI) was assessed to develop a new selective and sensitive gas chromatography-high resolution mass spectrometry (GC-HRMS) method for the determination of polychlorinated naphthalenes (PCNs) in sediment samples. The capability of both APCI and APPI sources for the ionization of PCNs was investigated, showing the formation of the molecular ion and the [M‒Cl+O]‒ ion in positive and negative ion modes, respectively. Positive ion APCI provided high responses using high corona ion current, while the use of high vapour pressure dopant-solvents, such as toluene in positive mode and diethyl ether in the negative mode, was required to achieve high ionization efficiencies in APPI. The performance of the two API sources in the PCN determination by GC-HRMS were compared and the best results were achieved using the GC-APPI(+)-HRMS (Orbitrap) system. The GC-APPI(+)-HRMS (Orbitrap) method was applied to the characterization of Halowax mixtures and the analysis of marine sediments collected near to the coastal area of Barcelona (NE, Spain), demonstrating a great detection capability with low method limits of detection (0.2–1.6 pg g−1 dry weight), good precision (RSD <15%) and trueness (relative error <13%). Total PCN concentrations ranged from 0.35 to 5.0 ng g−1 dry weight and the presence of related compounds, such as polychlorinated biphenyls (PCBs), was also detected by combining positive and negative ion modes, providing complementary information to better monitor of all PCN congener groups. The results presented here show the feasibility of the GC-APPI-HRMS method for the suitable determination of PCNs.

The occurrence and distribution of polychlorinated naphthalenes (PCNs), focusing on tissue-specific bioaccumulation in crucian carp in South Korea

The occurrence and distribution of 41 congeners of polychlorinated naphthalenes (PCNs) were investigated in major tissues of crucian carp (muscle, gonad, liver, and blood) and in river sediment to assess the bioaccumulation potential of PCNs. The total PCN concentrations in sediment ranged from 4.37 to 19.5 pg/g dry weight (dw), mainly comprising CN-13, CN-33/34/37, and CN-38/40. Among fish tissues, higher PCN concentrations were observed in the gonads (29.6 ± 10.3 pg/g wet weight, ww) and liver (25.7 ± 4.35 pg/g ww) of crucian carp than in the muscle (2.17 ± 0.68 pg/g ww). CN-28/43, CN-33/34/37, CN-42, CN-52/60, CN-53/55, and CN-66/67 congeners were detected most frequently and had the highest concentration among all crucian carp tissues. We investigated the association between the PCN concentration in each tissue (muscle, liver, and gonad) and the size of the fish (total length and weight) and found positive correlations between the PCN concentration in the gonads and the total length and weight (p < 0.05, Spearman correlation).

Concentrations and trophic magnification of polychlorinated naphthalenes (PCNs) in marine fish from the Bohai coastal area, China.

Polychlorinated naphthalenes (PCNs) have been found widely in the aquatic environment and can be transferred through food chains, which can magnify or dilute their toxic effects on humans. In this study, PCNs were analyzed in samples of 17 species of fish with different dietary habits collected in the Bohai coastal area in China. Dichloronaphthalenes, which have rarely been quantified in previous studies, were determined. The total PCN concentrations were from 7.3 to 214 pg/g wet weight, and the highest concentration was found in ditrema. The trichloronaphthalenes were the most abundant PCNs, followed by the dichloronaphthalenes and pentachloronaphthalenes. The relatively high contributions of the less-chlorinated homologs to the total PCN concentrations indicated that the main PCN sources around the Bohai were industrial thermal process emissions rather than technical PCN formulations. The trophic magnification factors of the PCN homologs were from 3.1 to 9.9, indicating that PCNs were biomagnified by fish. The trophic magnification factor of dichloronaphthalene and trichloronaphthalenes was 5.8 and 6.4, respectively, indicating for the first time that dichloronaphthalene and trichloronaphthalenes can undergo trophic magnification by fish. The two highest trophic magnification factors were for the pentachloronaphthalenes and hexachloronaphthalenes, probably because these PCNs having fewer vicinal carbon atoms without chlorine atoms attached are less easily biotransformed than the other homologs. The dioxin-like toxicities of the PCNs in the samples, expressed as potential toxic equivalences (TEQs), were assessed. The highest total TEQ was 0.0090 pg/g ww, in Pacific herring, and the hexachloronaphthalenes were the dominant contributors to the total TEQs in the fish samples. The PCN TEQs were much lower than the polychlorinated dibenzo-p-dioxin and dibenzofuran and dioxin-like polychlorinated biphenyl TEQs found in fish from the Bohai in previous studies, and made marginal contributions to overall human exposure to dioxin-like TEQs, suggesting that PCNs pose no toxicological concerns.

Polychlorinated naphthalenes (PCNs) in seafood: Estimation of dietary intake in Korean population

Polychlorinated naphthalenes (PCNs) were measured in 33 seafood species including fish, mollusks and crustaceans purchased from local markets in five Korean cities between 2012 and 2013. Five samples were collected from each species for the measurements. Thirty-seven PCN congeners from tetra-CN to octa-CN were measured. Octa-CN (octachloronaphthalene) was not detected in any of the samples. Tetra-CN and penta-CN were the predominant homologues of PCNs in seafood samples with PCN 51 and PCN 52/60 being the most abundant congeners in the samples. Total PCNs concentrations and their corresponding dioxin-like toxic equivalent (TEQ) values ranged from non-detection (ND) to 110pg/g on a wet weight (ww) basis and from ND to 0.14pg-TEQ/g ww, respectively. The estimated daily intake of total PCNs based on an absolute content and TEQ potency were estimated for the Koreans to be 570pg/day and 0.44pg-TEQ/day, respectively. However, the estimated TEQ value of PCNs intake from seafood, represented only a small fraction (3.0%) of the total TEQ intake from consumption of seafood in Korean population. This is the first report to exhibit the presence of PCNs in seafood samples collected from local markets in Korea and their intake by general population.

Congener specific determination of polychlorinated naphthalenes in sediment and biota by gas chromatography high resolution mass spectrometry

An isotope dilution congener-specific method for the determination of the most abundant and most toxic polychlorinated naphthalenes (PCNs) was developed using gas chromatography with high resolution mass spectrometry (GC-HRMS). The method was used to determine the concentration of 24 target congeners and total PCN concentrations in fish and sediment samples. Tissue samples were extracted using pressurized liquid extraction (PLE) and sediment samples were extracted using Soxhlet extraction. Sample extracts were cleaned up using either a manual two-stage open column procedure or an automated FMS Power Prep System with multi-analyte and multi-sample capability using a three-column cleanup procedure. Sediment extracts were cleaned up with a dual open column cleanup technique involving the use of both a multi-layered silica (silver nitrate/acid/base/neutral silica) column followed by column containing carbon-activated silica. Fish tissue extracts were cleaned up on the automated system involving the use of a high capacity ABN (acid/base/neutral column), carbon celite column, and a basic alumina column. The method is capable of producing instrument detection limits (IDLs) between 0.06 and 0.13pg for each PCN (on column), with method detection limits (MDLs) for the fish extracts ranging from 1.3 to 3.4pg/g (wet weight) and 0.46 to 1.2pg/g (dry weight) for sediments. The average accuracy of 34 spiked fish samples analysed over a period of several months was 100% with a precision (%RSD) of 12%. Similarly, the average accuracy for 28 spiked sediment samples was 104% with a precision (%RSD) of 12%. The application of the method to environmental samples was demonstrated through the analysis of sediment and fish samples obtained from Lake Ontario, Canada. The method is used both for the determination of 24 PCNs and to perform non-targeted screening for the remaining 51 PCN congeners, which are included in the total PCN quantification result. It is currently one of the most comprehensive and accurate congener-specific methods available and was developed from the existing techniques used for the determination of polychlorinated dioxins and furans to produce high quality data with only minor modifications in the clean-up procedure. It can therefore be readily adopted by other laboratories performing dioxin and POP analyses.

Thermal destruction of wastes containing polychlorinated naphthalenes in an industrial waste incinerator.

A series of verification tests were carried out in order to confirm that polychlorinated naphthalenes (PCNs) contained in synthetic rubber products (Neoprene FB products) and aerosol adhesives, which were accidentally imported into Japan, could be thermally destroyed using an industrial waste incinerator. In the verification tests, Neoprene FB products containing PCNs at a concentration of 2800mg/kg were added to industrial wastes at a ratio of 600mg Neoprene FB product/kg-waste, and then incinerated at an average temperature of 985°C. Total PCN concentrations were 14ng/m3N in stack gas, 5.7ng/g in bottom ash, 0.98ng/g in boiler dust, and 1.2ng/g in fly ash. Destruction efficiency (DE) and destruction removal efficiency (DRE) of congener No. 38/40, which is considered an input marker congener, were 99.9974 and 99.9995%, respectively. The following dioxin concentrations were found: 0.11ng-TEQ/m3N for the stack gas, 0.096ng-TEQ/g for the bottom ash, 0.010ng-TEQ/g for the boiler dust, and 0.072ng-TEQ/g for the fly ash. Since the PCN levels in the PCN destruction test were even at slightly lower concentrations than in the baseline test without PCN addition, the detected PCNs are to a large degree unintentionally produced PCNs and does not mainly stem from input material. Also, the dioxin levels did not change. From these results, we confirmed that PCNs contained in Neoprene FB products and aerosol adhesives could be destroyed to a high degree by high-temperature incineration. Therefore, all recalled Neoprene FB products and aerosol adhesives containing PCNs were successfully treated under the same conditions as the verification tests.

Concentrations and patterns of polychlorinated naphthalenes in surface sediment samples from Wuxi, Suzhou, and Nantong, in East China

The concentrations and patterns of polychlorinated naphthalenes (PCNs) were determined in surface sediment samples from Wuxi, Suzhou, and Nantong, in the Yangtze River Delta (East China), which has become urbanized rapidly. The total PCN (tri- to octachlorinated naphthalenes) concentrations in the samples from Wuxi, Suzhou, and Nantong were 0.89–40, 2.8–4600, and 0.60–34ng/gdry weight, respectively. Unexpectedly high PCN concentrations were found in four of the sediment samples. The PCN concentrations were much higher in the samples from the Beijing–Hangzhou Grand Canal than in the samples from the Yangtze River. The toxic equivalent (TEQ) concentrations (determined from the concentrations of the “dioxin-like” PCNs) ranged from 1.45×10−7 to 2.16ngTEQ/g, and the congeners CN-66/67 and CN-73 were the predominant contributors to the TEQs. Independent samples t-tests were performed, and no significant differences were found between the PCN concentrations in the samples from the metropolitan area and the development zone when the four development-zone samples that contained very high PCN concentrations were excluded. The PCN profiles were dominated by the hexa- to octachlorinated naphthalene homologs. The CN-66/67 to CN-71/72 and CN-66 to CN-67 concentration ratios were used to identify specific PCN sources. Emissions from chemical and other industrial plants were found to have strongly influenced the PCN concentrations in sediment in the study area.

Identification and preliminary evaluation of polychlorinated naphthalene emissions from hot dip galvanizing plants

Hot dip galvanizing (HDG) processes are sources of polychlorinated-p-dioxins and dibenzofurans (PCDD/Fs). Close correlations have been found between the concentration of PCDD/Fs and polychlorinated naphthalenes (PCNs) that are produced and released during industrial thermal processes. We speculated, therefore, that HDG plants are potential PCN sources. In this preliminary study, PCNs were analyzed in solid residues, ash and precipitate from three HDG plants of different sizes. The total PCN concentrations (∑2–8PCNs) in the residue samples ranged from 60.3 to 226pgg−1. The PCN emission factors for the combined ash and precipitate residues from the HDG plants ranged from 75 to 178ngt−1 for the dichlorinated and octachlorinated naphthalenes. The preliminary results suggested that the HDG industry might not currently be a significant source of PCN emissions. The trichloronaphthalenes were the dominant homologs followed by the dichloronaphthalenes and the tetrachloronaphthalenes. The PCN congeners CN37/33/34, CN52/60, CN66/67, and CN73 dominated the tetrachlorinated, pentachlorinated, hexachlorinated, and heptachlorinated naphthalene homologs, respectively. The PCNs emitted from the HDG plants had similar homolog distributions and congener profiles to the PCNs emitted from combustion plants and other metallurgical processes. The identification and preliminary evaluation of PCN emissions from HDG plants presented here will help in the prioritization of measures for controlling PCN emissions from industrial sources.

Investigation of seasonal variations and sources of atmospheric polychlorinated naphthalenes (PCNs) in an urban area

Atmospheric concentrations of 32 polychlorinated naphthalene (PCN) congeners were determined at four sites (i.e., Suburban, Urban 1, Urban 2, and Industrial) in Izmir, Turkey and their possible sources were investigated. Total PCN (Σ32PCN) concentrations ranged between 5.2 (Suburban 1) to 162pg m−3 (Urban 1) in summer, while in winter, they ranged from 3.7 (Suburban) to 229pg m−3 (Urban 1). PCN–24/14 was the dominant congener at all sites (contributing 12–27% to Σ32PCNs), followed by PCN–33/34/37, PCN–28/43, PCN–17/25, PCN–23 and PCN–19. Investigation of possible sources indicated that the combustion processes also contribute substantially to atmospheric PCN concentrations in addition to emissions from sources related to historical use of technical mixtures.

Polychlorinated naphthalenes in human adipose tissue from New York, USA

Polychlorinated naphthalenes (PCNs) are persistent, bioaccumulative, and toxic contaminants. Prior to this study, the occurrence of PCNs in human adipose tissues from the USA has not been analyzed. Here, we have measured concentrations of PCNs in human adipose tissue samples collected in New York City during 2003–2005. Concentrations of PCNs were in the range of 61–2500 pg/g lipid wt. in males and 21–910 pg/g lipid wt. in females. PCN congeners 52/60 (1,2,3,5,7/1,2,4,6,7) and 66/67 (1,2,3,4,6,7/1,2,3,5,6,7) were predominant, collectively accounting for 66% of the total PCN concentrations. Concentrations of PCNs in human adipose tissues were 2–3 orders of magnitude lower than the previously reported concentrations of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). Concentrations of PCNs were not correlated with PCB concentrations. The contribution of PCNs to dioxin-like toxic equivalents (TEQs) in human adipose tissues was estimated to be <1% of the polychlorinated dibenzo- p-dioxin/dibenzofuran (PCDD/F)-TEQs.

Levels and distributions of polychlorinated naphthalenes in sewage sludge of urban wastewater treatment plants

Over seventy congeners of polychlorinated naphthalenes (PCNs) in sewage sludge of 8 urban wastewater treatment plants (WWTPs) in Beijing were analyzed by isotope dilution, and high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) method. The total PCN concentrations determined in the samples range from 1.48 to 28.21 ng/g dw (dry weight) with TEQ concentrations of 0.11–2.45 pg/g dw. These levels were lower than those found in other regions. DiCNs and TrCNs were the most dominant homologues of PCNs. The similar congener profiles in all the samples suggest the similarity in certain sources. Contamination from industrial input might be the most significant source of PCNs in the sludges in this study, and thermal processes such as waste incineration and coal combustion may be another source of the PCNs contamination.

Distribution of Persistent Organohalogen Compounds in Pine Needles from Selected Locations in Kentucky and Georgia, USA

Epicuticular wax of pine needles accumulates organic pollutants from the atmosphere, and the pine needle samples have been used for monitoring both local and regional distributions of semivolatile organic air pollutants. One-year-old pine needles collected from residential and industrial locations in western Kentucky and the vicinity of Linden Chemicals and Plastics, a Superfund Site at Brunswick, Georgia, were analyzed for polychlorinated biphenyls (PCBs), major chlorinated pesticides, and polychlorinated naphthalenes (PCNs). Total PCB concentrations in pine needles from Kentucky ranged from 5.2 to 12 ng/g dry weight (dw). These sites were comparatively less polluted than those from the Superfund Site, which had total PCB concentrations in pine needles in the range of 15-34 ng/g dw. Total chlorinated pesticides concentrations in pine needles ranged from 3.5 to 10 ng/g dw from Kentucky. A similar range of concentrations of chlorinated pesticides (7.3-12 ng/g dw) was also found in pine needle samples from the Superfund site. Total PCN concentrations in pine needles ranged from 76 to 150 pg/g dw in Kentucky. At the Superfund Site, total PCN concentrations ranged from 610 pg/g dw to 38,000 pg/g dw. When the toxic equivalencies (TEQs) of PCBs in pine needles were compared, Kentucky was relatively lower (0.03-0.11 pg/g dry wt) than the TEQs at the Superfund Site (0.24-0.48 pg/g dry wt). The TEQs of PCNs from Kentucky (0.004-0.067 pg/g dw) were much lower than the TEQs from locations near the Superfund Site (0.30-19 pg/g dry wt). The results revealed that pine needles are excellent, passive, nondestructive bioindicators for monitoring and evaluating PCBs, chlorinated pesticides, and PCNs.

Polychlorinated naphthalenes in groundwater samples from the Llobregat aquifer (Spain)

Polychlorinated naphthalenes (PCNs) have characteristics fairly similar to those of polychlorinated biphenyls and terphenyls (PCBs and PCTs) and although they have been used in numerous applications, very few reports on the occurrence of PCNs in water have been published. Both automated solid-phase extraction (SPE) and liquid-liquid extraction (LLE) procedures were evaluated to concentrate PCNs. High-resolution gas chromatography with electron-capture detection (HRGC-ECD) and mass spectrometric detection in the selected ion monitoring mode (SIM) were used to analyze PCNs in groundwater samples from the aquifer of the Llobregat river near Barcelona (NE Spain). The homologue distribution profiles of PCNs found in groundwater samples and the standard mixtures of Halowax (1099, 1013 and 1014) were compared. Quantification was achieved by HRGC-ECD. Total PCN concentrations expressed as Halowax 1099 equivalents ranged from <0.5 ng/l to 79.1 μg/l in the water samples, with tetrachloronaphthalenes (TetraPCN) as the major group of congeners.

Determination of polychlorinated naphthalenes in polychlorinated biphenyl products via capillary gas chromatography—mass spectrometry after separation by gel permeation chromatography

A gel permeation chromatographic method was developed for the isolation and determination of small amounts of polychlorinated naphthalenes (PCNs) present in polychlorinated biphenyl (PCB) products. The method was applied to nine commercial PCB products: Aroclor 1016, 1232, 1242, 1248, 1254 and 1260 and Clophen A30, A40 and A50. All products were found to contain total PCN concentrations between 1.8 and 870 μg/g. High concentrations of PCNs were detected in Clophen A30 and A40 whereas a low concentration was found in Clophen A50. The PCN congeners were dominated by compounds substituted with two to six chlorine atoms.