Levels and trends of PCDD/Fs and PCBs in camel milk (Camelus bactrianus and Camelus dromedarius) from Kazakhstan

To date, despite the fact it represents a very important part of the national dairy production, no data are available concerning the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) in camel milk from the Republic of Kazakhstan. Selected PCDDs, PCDFs, and PCBs were measured in pools of milk from camels (n=15) located in various places of Kazakhstan (Almaty, Atyrau, Aralsk, Shymkent) and sampled at two different seasons for two different species (Camelus bactrianus and Camelus dromedarius). Non-dioxin-like (NDL-)PCB concentrations (6.3±2.7 ng g(-1) fat, median 5.1 ng g(-1) fat, range 0.6-17.4 ng g(-1) fat) were far below the maximum value of 40 ng g(-1) fat proposed by the EU. Dioxin-like (DL-)PCB concentrations (1.7±0.7 ng g(-1) fat, median 1.5 ng g(-1) fat, range 0.3-4.2 ng g(-1) fat) and the NDL-PCB to DL-PCB ratio (4.3) were similar to what is reported in EU for cow-based dairy products. PCB 52 and PCB 101 appeared to be proportionally more present in Kazakh camel milk samples (>60% of the sum of the 6 indicator NDL-PCBs) than in European cow milk samples (<10% of the sum of the 6 indicator NDL-PCBs), indicating possible differences in the route of exposure to PCBs in Kazakhstan. PCB 105 and PCB 118 appeared to be present at higher concentrations in camel milk (>80% of the sum of the 12 DL-PCBs). PCB 105, PCB 118 and PCB 156 were the major congeners for DL-PCBs, accounting for 92% of the sum of concentrations of DL-PCBs (88% for Belgian cows). In terms of TEQ, PCB 126 and PCB 118 are the major contributors and represent, respectively, 80% and 14% of the DL-PCB TEQWHO05 concentrations. No significant interracial or geographical trends were observed for NDL- and DL-PCB profiles. However, concentrations of all DL-PCBs appeared to be significantly higher for samples collected in Atyrau region. 2,3,7,8-TCDD level (mean 0.08±0.07 pg g(-1) fat, median 0.08 pg g(-1) fat, range 0.00-0.18 pg g(-1) fat, 60%>LOQs) were very low for all samples and 2,3,4,7,8-PeCDF was the major contributor (27%) to the PCDD/F TEQWHO05. Considering the total TEQWHO05 (sum of DL-PCBs and PCDD/Fs), DL-PCB and PCDD/F contributed for 73% and 27%, respectively. A decrease of only 1% of the total TEQ was observed when using the TEFWHO05 scale instead of the TEFWHO98 scale. Two samples collected in the region of Atyrau exceeded the EU maximum level value of 6.00 pg TEQWHO98 g(-1) fat (6.4 pg TEQWHO05 g(-1) fat and 6.9 pg TEQWHO05 g(-1) fat). Both samples exceeded the EU action level for the sum of DL-PCBs. Based on the fact that camel milk is used to prepare popular traditional fermented drinks like shubat, this suggests that the human exposure in the Caspian Sea region of Atyrau should be expected to be higher than in the other regions studied here.     

Polychlorinated dibenzo-p-dioxins, dibenzofurans and 'dioxin-like' PCBs in flue gas emissions from municipal waste management plants

The aim of this work is to give representative data on polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyl (PCBs) from stack gas emissions of an urban solid waste management plant which has to comply with the limit of 0.1 ng I-TEQ/Nm3. In particular, the study is focused on 29 target compounds, the seventeen 2,3,7,8-PCDDs/Fs, four non-ortho PCBs and eight mono-ortho PCBs which configure so-called 'dioxin-like' PCBs (DL-PCBs). To this end, emission measurements were performed during one year over the three operating combustion lines in a selected waste management plant. In general, accurate methodology allowed characterizing all target compounds in almost all the samples analyzed. In addition, a typical pattern for DL-PCBs is reported. The pattern presented PCB #118 to be the highest, nevertheless the figures demonstrated DL-PCBs contribution to the total TEQ around 3% being PCB #126 the most important congener due to its TEF of 0.1. Finally, remarkable differences were achieved in comparison with both environmental and biological samples such as soils, sediments, human milk or fish since these matrices may present DL-PCB contribution to the total TEQ up to 77%.     

Levels and congener profiles of PCBs and PCDD/Fs in blue shark (Prionace glauca) liver from the South-Eastern Mediterranean Sea (Italy)

Liver of blue shark (Prionace glauca) specimens from the South-Eastern Mediterranean Sea were analyzed for the presence of polychlorinated biphenyls (PCBs), including coplanar congeners, polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). PCBs were the dominant chemicals, followed by PCDFs and PCDDs. The pattern of PCB congener concentrations in the hepatic tissue was dominated by higher chlorinated compounds. The specific profile of toxic PCDD/F congeners was characterized mainly by 2,3,7,8-TCDF and 2,3,7,8-TCDD, followed by 1,2,3,6,7,8-HxCDD and 2,3,4,6,7,8-HxCDF. The total 2,3,7,8-TCDD toxic equivalent (TEQs) was 149 pg g⁻¹ lipid wt. The profile of TEQ shows that PCDDs present the greatest risk to this species contributing to total toxicity with a percentage approximately of 60%, while the contribution of PCDFs and DL-PCBs is almost the same being 22.4% and 21.6%, respectively. Further investigations are urgently needed to characterize the PCDD/Fs contamination levels not only in elasmobranch fish but in all Mediterranean marine biota.     

Congener-specific egg contribution of polychlorinated biphenyls to nestlings in two passerine species

Quantifying polychlorinated biphenyl (PCB) residues in nestlings of avian species is a common method for assessing trophic transfer and risk at PCB-contaminated sites. The proportion of nestling PCB mass due to maternal transfer is often accounted for by subtracting total PCB mass in eggs from nestlings. However, variation in physicochemical properties and metabolism among congeners may lead to differences between egg contribution based on total PCBs and dioxin-like congeners. We examined congener-specific variation in contribution of PCBs from eggs to nestlings in tree swallows and European starlings. Egg contribution of total PCB mass was 14.3 and 16.2%, respectively, whereas contribution based on dioxin-like congeners was 14.8 and 13.6%, respectively. These data suggest that using total PCB mass in eggs to adjust estimates of PCB accumulation in nestlings may not reflect patterns for dioxin-like congeners, potentially over or under-estimating the risk of toxicity of PCBs.     

Pesticides and PCBs in sediments and fish from the Salton Sea, California, USA

The Salton Sea, the largest manmade lake in California, is officially designated by the State of California as an agricultural drainage reservoir. The purpose of this study was to determine organochlorine and organophosphorous pesticides, as well as polychlorinated biphenyl (PCB) concentrations in sediments and fish tissues in the Salton Sea and evaluate the relative ecological risk of these compounds. Sediment samples were taken during 2000-2001 and fish tissues (Tilapia mossambique, Cynoscion xanthulu) were collected in May 2001. All samples were analyzed for 12 chlorinated pesticides, 6 organophosphorus pesticides, and 55 polychlorinated biphenyl (PCB) congeners. SigmaDichlorodiphenyltrichloroethane (SigmaDDT) and total PCB concentrations observed in sediments ranged from 10 to 40 and 116 to 304 ng/g dry wt, respectively. DDT/DDD ratios in sediments and fish tissues of the northern Sea in 2001 indicated recent DDT exposure. Lindane, dieldrin, dichlorodiphenylethane (DDE) and total PCB concentrations detected in sediments exceeded probable effect levels established for freshwater ecosystems, and pp-DDE and total PCB concentrations were higher than effect range-median values developed for marine and estuarine sediments. In fish liver, concentrations of endrin and SigmaDDT exceeded threshold effect level established for invertebrates. SigmaDDT concentrations detected in fish tissues were higher than threshold concentrations for the protection of wildlife consumers of aquatic biota. DDE concentrations in fish muscles tissues were above the 50 ng/g concentration threshold for the protection of predatory birds. Dimethoate, diazinon, malathion, chlorpyrifos, disulfoton varied from < or = 0.15 to 9.5 ng/g dry wt in sediments and from < or = 0.1 to 80.3 ng/g wet wt in fish tissues. Disulfoton was found in relatively high concentrations (up to 80.3 ng/g) in all organs from Tilapia and Corvina. These results demonstrate continued contamination of specific organochlorine compounds in sediments and resident fish species of the Salton Sea.     

Digestibility, retention and incorporation of low-level dietary PCB contents in laying hens

Polychlorinated biphenyls (PCBs) are persistent and hazardous environmental contaminants, which tend to bioaccumulate in the food chain. In the present report the long-term effect of low-level dietary PCB concentrations was studied on performance, egg quality, apparent PCB digestibility, apparent PCB retention and PCB accumulation in laying hens that were fed experimental diets for 41 weeks. The tested dietary concentrations of supplemented PCBs, based on the sum of seven reference congeners, were 0, 1.5 and 6 ng/g. PCB ingestion did not significantly affect performance or egg quality parameters. The PCB concentration in egg yolk reached a nearly constant level after approximately 40 and 70 days of consumption of the diets containing 1.5 and 6 ng PCBs/g, respectively. Apparent faecal PCB digestibility and apparent retention were not influenced by dietary levels of added fat varying between 1.5% and 4.5%, but were significantly higher in hens fed diets containing added PCBs. Moreover, apparent PCB digestibility and retention increased significantly with age. Among the seven individual PCB congeners, no systematically significant differences with regard to apparent faecal digestibility were observed throughout the experiment. Accumulation of PCBs in the fat fraction of egg yolk, abdominal adipose tissue and thigh and breast muscle greatly depended upon PCB intake, but never exceeded the maximally allowed concentration of 200 ng/g. As PCBs 52 and 101 were hardly found in egg yolks and hen tissues, it was concluded that both congeners were greatly metabolised. Comparison of relative contents of individual PCB congeners revealed that PCBs 118, 138 and 153 were preferentially incorporated in yolk and body tissues.     

Spatial distribution and source apportionment of PCBs in sediments around İzmit industrial complexes, Turkey

The spatial distribution, degree of pollution and major sources of PCBs were evaluated in surficial sediments within the heavily urbanized and industrialized ?zmit Bay and its main freshwater inputs. ΣPCB concentrations range from 2.90 to 85.4ngg(-1) in marine sediments and from ND to 47.7ngg(-1) in freshwater sediments. Results suggest that high concentrations of ΣPCBs were localized around a chlor-alkali plant and an industry that handles bulk liquid, dry and drummed chemicals, and petroleum products in the Bay. Using a chemical mass balance receptor model (CMB), major sources of PCBs in the region were investigated. The CMB model identified Aroclor 1254 and 1260 to be the major PCB sources in marine sediments and the less chlorinated Aroclor 1248 and 1242 as the major PCB sources in freshwater sediments. The potential sources for the PCBs were briefly discussed in terms of their use in various industrial applications.     

Assessment of the daily intake of 62 polychlorinated biphenyls from dietary exposure in South Korea

The dietary intake of polychlorinated biphenyls (PCBs) was estimated using the sum of 62 PCB congeners (∑₆₂PCBs), including seven indicator PCBs and 12 dioxin-like PCBs, in the South Korea. In this study, 200 individual food samples belonging to 40 different foodstuffs were investigated to estimate the distribution of PCB congeners in five sampling cities. PCB exposure was estimated using Korean dietary habits as established by the National Health and Nutrition Examination Survey (NHANES). The PCB concentrations in rice, the most frequently consumed food in Korea, was relatively low in whole food samples. The mean PCB levels measured in fish were the highest in this study, but each fish is consumed in relatively small amounts by the general population. Therefore, the daily dietary intake should also be considered with regard to human exposure to PCBs, especially with the consumption of contaminated foods. Dioxin-like PCB levels were also calculated using TEF values that were established in 2005. The average levels (pg TEQ/g) were 0.0002 for rice and 0.0098 for fish. The dioxin-like PCBs accounted for a relatively small percentage of the total PCBs, compared to previous studies. According to our research, the health risks associated with exposure to PCBs could be estimated using the tolerable daily intake (TDI) of the general population.     

Congener-specific approach to human PCB concentrations by serum analysis

The objective of this study was to evaluate all congeners of polychlorinated biphenyls (PCBs) in human serum samples. Concentrations of all PCB congeners in the serum of 87 volunteers were determined by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). The participants consisted of 47 males and 40 females, including 25 men working at municipal solid waste incinerators (MSWIs). The mean concentrations of total PCBs and dioxin-like PCBs were 242.77ng/g lipid (median: 180.17ng/g lipid) and 18.57ng/g lipid (median: 15.34ng/g lipid), respectively. Penta-, hexa-, and heptachlorinated biphenyls contributed more than 80% of the total PCBs detected in human serum. Congener-specific analysis indicated that PCB153, PCB138, PCB180, PCB187, and PCB118 contributed 57.3% of the total PCBs detected in human serum samples. A statistical analysis was performed to determine whether there were significant correlations between PCB concentrations and specific variables such as age, gender, smoking habits, occupation, and body mass index (BMI). However, serum PCB concentrations correlated only with age. In addition, we found that total PCBs and dioxin-like PCBs highly correlated with PCB153 (correlation coefficient r=0.93, p<0.01) and PCB118 (correlation coefficient r=0.98, p<0.01), respectively. Thus these two congeners could be satisfactory indicators for total PCBs and dioxin-like PCBs in human serum.     

Distribution characteristics of PCBs in the sediments of the lower Nakdong River, Korea

The objective of this study is to investigate the distribution characteristics of polychlorinated biphenyl (PCB) congeners in sediments of the lower Nakdong River of Korea. The sediments were collected using a grab sampler in May 1999. PCBs were extracted in the Soxhlet extractor and cleaned by using adsorption chromatographic techniques and concentrated sulfuric acid. A HP6890 gas chromatograph equipped with an electron capture detector was used for quantification. The results of congener specific analysis showed that the total concentration is ranged over 1.1-141 ng/g dry weight. The levels of PCB congeners are significantly correlated with the total organic carbons (TOC) in the sediments. The major fractions of PCBs in these sediments are congeners containing 4, 5 or 6 chlorine atoms per biphenyl molecule.     

Distribution characteristics of polychlorinated biphenyls in crucian carp (Carassius auratus) from major rivers in Korea

Polychlorinated biphenyls (PCBs) levels in crucian carp were determined at 20 locations along four major river systems, several small-scale rivers and a wetland in Korea. Twenty-eight congeners, ranging from tri- to hepta-CBs were detected. A gas chromatograph with a mass selective detector was used to quantify the individual PCB congeners. The objectives of this study were to investigate the levels of contamination of PCBs in freshwater fish and to observe the pattern of their distribution. The sampling locations were chosen among 31 sampling sites that are currently used as environmental residue checkpoints by the Korean Ministry of Environment. Concentrations of individual congeners ranged from not detectable (n.d.) to 0.75 ng g(-1) on a wet weight basis. The total concentrations of PCBs at each site ranged from n.d. to 5.41 ng g(-1) of wet weight. The most heavily contaminated site was the Nakdong estuary located near the Shinpyung-Janglim factory district. The PCB 153 and 138 were the principal congeners and penta- and hexa-chlorinated biphenyls comprised the main congener groups.     

Polychlorinated biphenyls in surface sediments of Yueqing Bay, Xiangshan Bay, and Sanmen Bay in East China Sea

The spatial distribution and source of polychlorinated biphenyls (PCBs) in 30 surface sediments of Yueqing Bay, Xiangshan Bay, and Sanmen Bay in Eastern China were analysed. Total concentrations of PCBs ranged from 9.33 to 19.60 ng g⁻¹ dry weight for all the sampling stations. The observed PCB levels were lower than those in areas of high urbanisation or contamination in the bay. Low-chlorinated PCBs, dominated by tri-PCB, were identified as the prevalent contaminate of surface sediments, and the top three PCB congeners were lighter chlorinated congeners (PCB 8, PCB 18 and PCB 28). These results were in agreement with the fact that tri-PCB compounds are the dominant contaminants in China. The result of the principal component analysis revealed that all samples were similar in composition to Aroclor 1242, suggesting they might originate from electrical capacitors and transformers. The levels of PCBs were significantly correlated with the total organic carbon in the sediments.     

Distribution patterns of nitrobenzenes and polychlorinated biphenyls in water, suspended particulate matter and sediment from mid- and down-stream of the Yellow River (China)

Samples of water, suspended particulate matter (SPM) and sediment were collected from mid- and down-stream of the Yellow River. The distribution and concentration of 10 nitroaromatic compounds and polychlorinated biphenyls (PCBs) were extensively studied. The total concentration of 10 nitrobenzenes (SigmaNBs) varied from 0.269 to 9.052 microg l(-1) in water, from 2.916 to 164.4 microg kg(-1) dry weight in SPM, and from 0.954 to 14.72 microg kg(-1) dry weight in sediment. PCBs associated with the sediments, measured as the summed responses of Aroclor 1242, 1248, 1254, 1260 (in comparison to those of a standard 1:1:1:1 mixture), were found to be in the range of non-detectable to 5.98 microg kg(-1). In the samples collected, various PCB congeners showed similar distribution characteristics with congeners containing 3-5 chlorine atoms accounting for more than 96.4% of total PCB. In most of the samples, PCB concentrations occurred in the order: TetraCB > TriCB > PentaCB. Levels of SigmaNBs in the Yellow River were relatively low in comparison with values reported from other river and marine systems, and PCB levels were comparatively low. Relative to the PCBs, SigmaNBs showed significantly more difference among the various stations, presumably due to the influence of different pollution sources. No obvious correlation was observed between the pollutant concentrations and either the TOC or the grain size of the sediments.     

Bioaccumulation profiles of polychlorinated biphenyls including coplanar congeners and possible toxicological implications in Baikal seal (Phoca sibirica)

Isomer specific concentrations of individual polychlorinated biphenyls (PCBs) including toxic non-ortho (IUPAC 77, 126, 169), mono-ortho (105, 118, 156) and di-ortho (137, 138, 153, 180) coplanar congeners were determined in the blubber of 40 Baikal seals (Phoca sibirica) and as their fish diet collected from Lake Baikal, Siberia. Residue levels of total PCBs in Baikal seals were noticeably high and comparable to those reported for seals from the North Sea, suggesting the recent usage of this compound in the watershed of Lake Baikal. Non-, mono-, and di-ortho coplanar congeners were also detected in Baikal seals and fish. An approach to estimate bioaccumulation profiles of PCB congeners revealed that the non-ortho PCBs, IUPAC 77, 126 and 169 seemed to be less persistent than other congeners. Furthermore, selective biotransformation of PCB congeners having either meta-para vicinal H atoms or both adjacent chlorinated meta-para and ortho-meta positions has been suggested. Comparison of 2,3,7,8-TCDD toxic equivalents (TEQ) of non-, mono- and di-ortho coplanar congeners in Baikal seals with those for other marine mammals suggested higher enrichment of mono-ortho congeners, particularly IUPAC 105 and 118, which contributed significantly to the total TEQs in Baikal seals. Results imply that the TCDD-like toxicity is relatively serious in Baikal seals, because of the enrichment of these toxic PCB congeners in tissues.     

Detection and quantitative analysis of polychlorinated biphenyls in tilapia from Hawaiian waters

The purpose of this study was to investigate polychlorinated biphenyls (PCBs) contamination in tilapia (Oreochromis mossambicus) collected from the Manoa stream and Ala Wai Canal of O'ahu, an island of the geographically isolated Hawaiian archipelago. Our results show that the average concentrations of PCBs varied from 51.90 to 89.42 ng g(-1) lipid weight for the sampling sites. Relative toxic potencies (RTPs) and toxic equivalencies (TEQs) were determined to be 20.38-40.60 ng TCDDg(-1) lipid weight and 2.89-4.17 ng TEQ g(-1) lipid weight by 7-ethoxy-resorufin-O-deethylase (EROD) activity analysis and calculation of PCB concentrations based on toxic equivalency factors (TEFs), respectively. Penta-chlorinated congeners were found to be predominant, which revealed that Aroclor 1254 was a possible major source of PCBs in our fish samples. PCB 118, an indicator PCBs, constituted more than 55% and 30% of the total PCBs and TEQs, respectively. In addition, PCB 118 was found to have a linear correlation to the total PCBs (R=0.975) and TEQs (R=0.782). Detection of concentrated PCBs in Hawaiian waters suggests a potentially adverse impact of this pollutant on human health, as well as ecological systems, and suggests the necessity of environmental monitoring and hazard assessment of PCBs within the Hawaiian Islands.     

Dietary uptake kinetics of polychlorinated biphenyls from sediment-contaminated sandworms in a marine benthic fish (Pseudopleuronectes yokohamae)

To evaluate the dietary uptake of polychlorinated biphenyls (PCBs) from live food, we investigated the dietary uptake and depuration kinetics of PCBs in a marine benthic fish (marbled sole, Pseudopleuronectes yokohamae) by using as food live sandworms (Perinereis nuntia) that were laboratory-exposed to field-collected PCB-contaminated sediment. Marbled sole were fed the PCB-contaminated sandworms for 28 d and then uncontaminated sandworms for 56 d. The assimilation efficiencies (AEs) of 84 PCB congeners via the gastrointestinal tract (GIT) to the muscle of the fish ranged from 0.21 to 0.78; whole-body AEs would be lower than those of muscle because of the lower PCB concentrations, on a lipid basis. The AEs determined in this study were lower than those in other studies that used PCB-spiked commercial pelletized food. The lower AEs found in this study might be attributable to differences in the food administered (live sandworms vs. commercial pellet food), possibly because of low digestibility of sandworm lipids by marbled sole. In addition, the AEs in this study tended to increase with increasing log octanol-water partition coefficients (K_OW) up to about seven, although AEs in the other studies using commercial pelletized food did not increase with increasing log K_OW. This result suggests the co-transport of highly hydrophobic PCB congeners along with lipids and fatty acids from the digested sandworms into the GIT epithelium cells. The growth-corrected half-lives of 26 PCB congeners in the muscle of fish ranged from 20 to 107 d.     

NDL-PCBs in muscle of the European catfish (Silurus glanis): An alert from Italian rivers

The non-dioxin-like polychlorinated biphenyls (NDL-PCBs) highly contribute to the PCB dietary intake of total PCBs. Most of the NDL-PCBs are assumed through ingestion of contaminated fish and fishery products. Therefore, it is important to quantify their presence in aquatic organisms to evaluate human risks associated with fish consumption. The European catfish is a top food-chain predator and is considered a reliable bio-monitoring tool reflecting the state of the environmental organic pollution. From 2006 to 2009, 54 European catfish were captured in four sites covering the area of the Po River (North Italy), and their muscles were analysed to determine the levels of 18 PCBs congeners. All samples presented detectable levels of 18 congeners and, on average, results showed an important presence of NDL-PCBs. The sum of the six congeners (28, 52, 101, 138, 153, 180 IUPAC) was used as indicator of the total PCBs concentration. The 33% of the samples analysed exceeded the maximum levels of 125 ng g⁻¹ set by European regulations in fish. The values measured ranged from 19.7 to 1015.4 ng g⁻¹ (mean 135.6 ± 149.8 ng g⁻¹).     

Human biomonitoring of polychlorinated biphenyls and polychlorinated dibenzodioxins and dibenzofuranes in teachers working in a PCB-contaminated school

Eighteen teachers from a highly contaminated school and 11 teachers from a control school participated in this study. Total polychlorinated biphenyl (PCB) indoor air concentration (six indicator congeners x 5) was beyond 12000 ng/m3 in some rooms of the contaminated school. PCB 28 and PCB 52 were the prevailing congeners. Whole blood was taken from each participant by the local health authority, pooled in two groups and analysed for the six PCB indicator congeners, non-ortho PCBs and polychlorinated dibenzodioxins (PCDD)/polychlorinated dibenzofurans (PCDF). Blood analysis showed elevated mean PCB 28 and PCB 52 levels for the exposed group, however the two groups were almost identical with regard to PCB 101, 138, 153 and 180. Moreover no difference can be observed for the concentration of non-ortho PCBs and PCDD/PCDF. The data support the finding, that heavy indoor air contamination with low chlorinated PCBs causes an increase of PCB 28 and PCB 52 blood levels. However, this increment was small compared to their total PCB load.     

Confirmation of polychlorinated biphenyl (PCB) distribution in the blood and verification of simple quantitative method for PCBs based on specific congeners

We measured the concentration of each polychlorinated biphenyl (PCB) congener in whole blood, plasma and blood cells, and investigated the distribution of PCBs in human blood using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). The PCB concentrations in plasma and whole blood in terms of lipid concentrations were almost equal, with a correlation coefficient of r = 0.972. In the blood, the ratio of PCBs in blood cells to those in plasma was generally about 1:9 and the congener distribution patterns in blood cells and plasma were similar.We performed verification of a simple mass screening method by obtaining information on the main PCB congeners for investigations on human accumulation and exposure. The total concentration of the seven PCB congeners (UNEP-7) proposed to the United Nations Environment Programme (UNEP) by Muir and Morita was about 50% of the total concentration of all PCB congeners, and UNEP-30 was about 80%. The seven main congeners in the blood (MCB-7) showed a value that was about 60%, and MCB-30 showed a value that was about 90%. Determinations with the main congeners in the blood showed a correlation of r = 0.990 or more between the main eight congeners (MCB-7 plus #74) and the total PCB concentration for all congeners. The results suggest that, although total PCB concentration can be effectively estimated from the main seven congeners, the main eight congeners would be preferable, and that the use of these congeners in the simple mass screening method would be effective for populations in areas uncontaminated by PCBs.     

Concentrations, spatial distributions and congener profiles of polychlorinated biphenyls in soils from a coastal city--Tianjin, China

A total of 82 surface soil samples collected from central urban sites, surrounding rural sites, coastal sites and background sites in Tianjin were analyzed for 84 PCB congeners. The mean values of total PCBs concentrations for surrounding rural sites, central urban sites, coastal sites, background sites and the whole Tianjin region were 4.45, 3.20, 12.65, 1.96 and 4.02 ng g(-1), respectively. No "urban fractionation effect" was found in Tianjin, which reflected the influence of local emission sources for PCBs such as industries and township enterprises in surrounding rural sites. In contrast, a "primary fractionation effect" was found in Tianjin region. The PCBs concentrations for whole Tianjin region showed a strong east-west gradient and the percentages of lighter molecular weight PCBs homologs (sum of di- to tetra-PCBs) to the total PCBs concentrations increased from east to west. The seven indicator PCBs concentrations were well correlated with the total PCBs concentrations with the correlation coefficients as 0.76 for Tianjin region and 0.74 for central urban sites, respectively. Predominant PCB homolog groups were penta- and tri-PCBs for Tianjin region. 10 dioxin-like PCBs concentrations were well correlated with total PCBs concentrations for all the sampling sites (R=0.79, P<0.0001). The TEQ concentrations for 10 dioxin-like PCBs were 5.3424 ng kg(-1) for Tianjin region and showed a strong east to west gradient. The spatial distribution of PCBs levels, homolog composition patterns and TEQ concentrations were all obviously influenced by local emission sources for PCBs in the east part of Tianjin region.