Tissue-specific accumulation of polybrominated diphenyl ethers (PBDEs) including Deca-BDE and hexabromocyclododecanes (HBCDs) in harbor seals from the northwest Atlantic

Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) are widely used flame retardants that enter coastal waters from multiple sources and biomagnify in marine food webs. PBDEs have been detected at relatively high concentrations in harbor seals, apex predators in the northwest Atlantic. Whereas tri- to hexa-BDEs readily biomagnified from prey fishes to seal blubber, Deca-BDE (BDE-209) did not biomagnify in blubber. To explore tissue-specific differences in the accumulation/biomagnification of BFRs, we analyzed tri- to Deca-BDES in liver of 56 harbor seals (6 adult males, 50 pups), and compared hepatic concentrations and biomagnification potential with those in blubber. HBCDs were analyzed in seal liver and blubber to enable similar comparisons. Hepatic ΣPBDE (tri- to Octa-BDE) concentrations (range 35–19,547 ng/g lipid weight, lw) were similar to blubber concentrations, while α-HBCD levels in seal liver (range 2–279 ng/g lw) were significantly higher than levels in blubber. Tissue distribution of PBDEs and α-HBCD varied significantly by age and, surprisingly, by gender among the pups. Biomagnification of α-HBCD from fish to seal liver and blubber was negligible to low, implying that harbor seals can metabolize this persistent isomer. Similar to the patterns in blubber, tri- through hexa-BDEs were highly biomagnified from fish to seal liver. In contrast, BDE-209 concentrations in liver were up to five times higher than those in blubber, which is consistent with observations that BDE-209 migrates to perfused tissues such as the liver in biota. Although detection frequency was low, BDE-209 levels in seal liver were up to ten times higher than those in their prey fish, suggesting that the accumulation/biomagnification of Deca-BDE in marine food webs is tissue-specific. As BDE-209 is the dominant PBDE found in marine sediments, its biomagnification in marine ecosystems is of concern.     

Levels and regional trends of persistent organochlorines and polybrominated diphenyl ethers in Asian breast milk demonstrate POPs signatures unique to individual countries

Human breast milk samples collected in 2007–2008 from four countries, Vietnam (Hanoi), China (Beijing), Korea (Seoul) and Japan (Sendai, Kyoto and Takayama), were analyzed for persistent organic pollutants (POPs) such as dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlordane-related compounds (CHLs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). Comparing with previous surveys, the present study indicates that the DDTs in breast milk from China and Vietnam had gradually decreased during the last decade, but were still 5–10 times higher than those in other nations. The ratios of p,p′-DDE/p,p′-DDT and o,p′-DDT/p,p′-DDT were higher in Beijing than in the other countries, suggesting that there is less fresh intake of commercial DDT products and a possible exposure to dicofol in China. CHL and PCB levels were relatively higher in mothers from Japan, whereas β-HCH and HCB were more common in Chinese women. In Japan, it is suspected that mothers in the urban/coastal area (Sendai) were more continuously exposed to organochlorine pesticides (OCPs) than mothers in the rural/inland area (Takayama). In addition, OCP levels in primiparae were significantly higher than those in multiparae from Japan and Korea. These indicate that both parity and regional factors are major determinants of the levels of OCPs and PCBs in human milk. On the other hand, higher concentrations of PBDEs were observed in mothers' milk from Korea. The congener was dominated by BDE-47 (43–54%), followed by BDE-153 (23–33%) in all regions except for Beijing where BDE-28 (23%) was relatively abundant. In Japanese breast milk, regional and parity-dependent distributions were not observed for PBDEs. Among PBDE congeners, age-dependency was observed for BDE-153, which was negatively correlated (p < 0.05) to the age of mothers in Kyoto (17 participants were housewives), while it increased with age in Sendai (10 participants were clerks). No such correlation was seen for BDE-47, indicating that BDE-47 was ingested and assimilated via different kinetics or routes from BDE-153 in Japan.     

Levels and trends of persistent organic pollutants in ringed seals (Phoca hispida) from Central West Greenland, with particular focus on polybrominated diphenyl ethers (PBDEs)

Polybrominated diphenyl ethers (PBDEs) and the organochlorine compounds polychlorinated biphenyls (PCBs), DDTs, HCB, chlordane-related pesticides, HCH and toxaphene were analysed in blubber of juvenile ringed seals from Central West Greenland collected between 1982 and 2006. The longest time series could be established for PBDEs, partly based on archived material, while PCBs and DDTs covered a study period from 1994-2006. All organochlorines showed decreasing trends, most pronounced for DDT and HCH with an annual change of 8%. BDE-47 had a significantly increasing trend of 5% annually. It was the only BDE congener consistently above the detection limit, with annual median concentrations between 0.78 ng/g lw to 3.54 ng/g lw, i.e. about 10 times lower than values from East Greenland observed in a similar time trend study on ringed seal blubber [Rigét F, Vorkamp K, Dietz R, Rastogi SC. Temporal trend studies on polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in ringed seals from East Greenland. J Environ Monit 2006; 8: 1000-5]. A clear East>West difference was also found for PCBs and DDTs, but not for chlordanes, toxaphene or HCHs. Sigma 10-PCB, Sigma DDT and Sigma Chlordanes had similar annual median concentrations, typically exceeding SigmaPBDE by two orders of magnitude. The concentrations of HCH and toxaphene were in an intermediate group, with highest annual median concentrations of 135 ng/g lw and 20 ng/g lw, respectively. For most compound groups, the circumpolar trend previously established under for example the Arctic Monitoring and Assessment Programme was confirmed, but apparently, more data are needed for chlordane-related compounds and toxaphene. Statistical analyses of the compound patterns in the ringed seal samples revealed significantly greater differences between seals from East and West than between different sampling years. Higher proportions of PCBs and DDTs and lower proportions of chlordanes and HCHs were found in seals from East Greenland than in those from West Greenland. Based on principal component analysis of individual congener and compounds, seals from East Greenland were found to contain higher proportions of the higher chlorinated CB congeners. Varying patterns between sampling locations may be caused by different exposure situations related to contaminant emissions and transport, but different feeding habits may also affect the contaminant composition.     

Organochlorine and heavy metals in newborns: Results from the Flemish Environment and Health Survey (FLEHS 2002–2006)

To collect regional information on internal levels of pollutants in humans in Flanders, 1196 mother–child pairs were systematically recruited in 2002–2003 via 25 maternities across Flanders. Cd, Pb, PCB congeners 118, 170, 138, 153 and 180, p,p′-DDE — a key metabolite of DDT- and hexachlorobenzene (HCB) were measured in cord blood or plasma. Cd was detected in 64% of the samples (geometric mean 0.21 µg/L cord blood). p,p′-DDE (110 ng/g plasma lipids) and Pb (14.7 µg/L blood), were measurable in nearly all samples. The individual PCB congeners could be detected in 40 to 81% of the newborns (138 + 153 + 180 = 64.4 ng/g plasma lipids). HCB (18.9 ng/g plasma lipids) and dioxin-like compounds measured by DR-CALUX® (23 pg CALUX-TEQ/g lipids) were above detection limit in more than 75% of the samples. Age and smoking habits of the mothers, did not influence the cord blood Pb and Cd levels. The organochlorines increased 4 to 9% per year of the mother's age (partial R² = 0.05 to 0.22). Mothers had 2.6% less PCBs in cord blood (partial R² = 0.02) for each unit increase in pre-pregnancy BMI. Season of delivery, breastfeeding previous children or consumption of local dairy products, were minor determinants. Up to 20% of the variability in organochlorine concentrations was explained by residence area. It was concluded that the place of birth in Flanders is an important determinant of the load of pollutants measured at the start of life. This underlines the validity of human biomonitoring on (relatively) small geographical scale.     

Biomagnification of naturally-produced methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in harbour seals and harbour porpoises from the Southern North Sea

Harbour seals and harbour porpoises are top predator species from the North Sea, have long life spans and hence, are known to accumulate high levels of anthropogenic contaminants. To gain knowledge about the behaviour of naturally-produced compounds in these marine mammals, the biomagnification of naturally-produced methoxylated polybrominated diphenyl ethers (MeO-PBDEs) was assessed. The biomagnification of MeO-PBDEs (2′-MeO-BDE 68 and 6-MeO-BDE 47) was lower in harbour seals (all biomagnification factors (BMFs) < 1) compared to the same age–gender groups of the harbour porpoises (all BMFs > 1). This may indicate a better metabolic breakdown of MeO-PBDEs in harbour seals, as was previously suggested for polybrominated diphenyl ethers (PBDEs). In both predators, 6-MeO-BDE 47 had the highest concentrations (range: 45–483 ng/g lw and 2–38 ng/g lw for harbour porpoises and seals, respectively) compared to 2′-MeO-BDE 68 (range: 2–28 ng/g lw and 1–6 ng/g lw for harbour porpoises and seals, respectively). In general, the highest concentrations were found in juveniles, suggesting an increased biotransformation capacity with age or the influence of dilution by growth for both species. Here we show that naturally-produced brominated organic compounds can biomagnify and accumulate in North Sea top predators, although to a lesser extent than anthropogenic lipophilic contaminants, such as polychlorinated biphenyls (PCBs) or PBDEs.     

Perfluoroalkyl substances in polar bear mother–cub pairs: A comparative study based on plasma levels from 1998 and 2008

Perfluoroalkyl substances (PFASs) are protein-binding blood-accumulating contaminants that may have detrimental toxicological effects on the early phases of mammalian development. To enable an evaluation of the potential health risks of PFAS exposure for polar bears (Ursus maritimus), an exposure assessment was made by examining plasma levels of PFASs in polar bear mothers in relation to their suckling cubs-of-the-year (~ 4 months old). Samples were collected at Svalbard in 1998 and 2008, and we investigated the between-year differences in levels of PFASs. Seven perfluorinated carboxylic acids (∑₇PFCAs: PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, and PFTrDA) and two perfluorinated sulfonic acids (∑₂PFSAs: PFHxS and PFOS) were detected in the majority of the mothers and cubs from both years. In mothers and cubs, most PFCAs were detected in higher concentrations in 2008 than in 1998. On the contrary, levels of PFOS were lower in 2008 than in 1998, while levels of PFHxS did not differ between the two sampling years. PFOS was the dominating compound in mothers and cubs both in 1998 and in 2008. Concentration of PFHpA did not differ between mothers and cubs, while concentrations of PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFTrDA, PFHxS, and PFOS were higher in mothers than in their cubs. Except from PFHpA, all compounds correlated significantly between mothers and their cubs. The mean cub to mother ratios ranged from 0.15 for PFNA to 1.69 for PFHpA. On average (mean ± standard error of mean), the levels of ∑₇PFCAs and ∑₂PFSAs in cubs were 0.24 ± 0.01 and 0.22 ± 0.01 times the levels in their mothers, respectively. Although maternal transfer appears to be a substantial source of exposure for the cubs, the low cub to mother ratios indicate that maternal transfer of PFASs in polar bears is relatively low in comparison with hydrophobic contaminants (e.g. PCBs). Because the level of several PFASs in mothers and cubs from both sampling years exceeded the levels associated with health effects in humans, our findings raise concern on the potential health effects of PFASs in polar bears from Svalbard. Effort should be made to examine the potential health effects of PFASs in polar bears.     

Associations of persistent organic pollutants with abdominal obesity in the elderly: The Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study

ObjectivesIn animal experiments, persistent organic pollutants (POPs) have induced visceral obesity. To address this possibility in humans, we evaluated associations between POPs and abdominal obesity both cross-sectionally and prospectively.MethodsTwenty-one plasma POPs (16 polychlorinated biphenyl (PCB) congeners, 3 organochlorine (OC) pesticides, 1 brominated diphenyl ether (BDE), and 1 dioxin) were measured at baseline in 970 participants aged 70 years of the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS), with prospective analyses in 511 participants re-examined after 5 years. Abdominal obesity was defined by an increased waist circumference.ResultsIn the cross-sectional analyses, concentrations of the less chlorinated PCBs, OC pesticides such as p,p′-DDE and dioxin had adjusted odds ratios of 2 to 3 for abdominal obesity. Many relations had inverted U-shapes rather than being linear, particularly in women. In contrast, concentrations of highly chlorinated PCBs were strongly inversely associated with abdominal obesity. In a single model including summary measures of the less chlorinated PCBs, highly chlorinated PCBs, and OC pesticides, both the positive associations and inverse associations strengthened. Similar but somewhat weaker associations were seen between POPs and risk of development of abdominal obesity in the prospective analyses.ConclusionUsing both a cross-sectional and a prospective design, low-dose exposure to less chlorinated PCBs, p,p′-DDE, and dioxin, were associated with existence or development of abdominal obesity, while highly chlorinated PCBs had an opposite association in an elderly population, despite the previous observation of higher incident diabetes associated with these same PCBs.     

Characteristics of PM10, PM2.5, CO2 and CO monitored in interiors and platforms of subway train in Seoul, Korea

This study was performed to investigate the concentration of PM₁₀ and PM_2.5 inside trains and platforms on subway lines 1, 2, 4 and 5 in Seoul, KOREA. PM₁₀, PM_2.5, carbon dioxide (CO₂) and carbon monoxide (CO) were monitored using real-time monitoring instruments in the afternoons (between 13:00 and 16:00). The concentrations of PM₁₀ and PM_2.5 inside trains were significantly higher than those measured on platforms and in ambient air reported by the Korea Ministry of Environment (Korea MOE). This study found that PM₁₀ levels inside subway lines 1, 2 and 4 exceeded the Korea indoor air quality (Korea IAQ) standard of 150 μg/m³. The average percentage that exceeded the PM₁₀ standard was 83.3% on line 1, 37.9% on line 2 and 63.1% on line 4, respectively. PM_2.5 concentration ranged from 77.7 μg/m³ to 158.2 μg/m³, which were found to be much higher than the ambient air PM_2.5 standard promulgated by United States Environmental Protection Agency (US-EPA) (24 h arithmetic mean: 65 μg/m³). The reason for interior PM₁₀ and PM_2.5 being higher than those on platforms is due to subway trains in Korea not having mechanical ventilation systems to supply fresh air inside the train. This assumption was supported by the CO₂ concentration results monitored in tube of subway that ranged from 1153 ppm to 3377 ppm. The percentage of PM_2.5 in PM₁₀ was 86.2% on platforms, 81.7% inside trains, 80.2% underground and 90.2% at ground track. These results indicated that fine particles (PM_2.5) accounted for most of PM₁₀ and polluted subway air. GLM statistical analysis indicated that two factors related to monitoring locations (underground and ground or inside trains and on platforms) significantly influence PM₁₀ (p < 0.001, R² = 0.230) and PM_2.5 concentrations (p < 0.001, R² = 0.172). Correlation analysis indicated that PM₁₀, PM_2.5, CO₂ and CO were significantly correlated at p < 0.01 although correlation coefficients were different. The highest coefficient was 0.884 for the relationship between PM₁₀ and PM_2.5.     

Toxicokinetics of dioxins and other organochlorine compounds in Japanese people: Association with hepatic CYP1A2 expression levels

Concentrations of persistent organochlorine compounds (OCs) including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) in the liver and adipose tissue of Japanese cadavers were measured, and their toxicokinetics were examined in association with hepatic cytochrome P450 (CYP) 1A protein expression levels. Total 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) were 66 ± 74 and 65 ± 57 pg/g lipid weight (mean ± S.D.) in the liver and adipose tissue, respectively. Total PCBs (sum of 62 congeners targeted), p,p′-dichlorodiphenyl-dichloroethylene (p,p′-DDE) and β-hexachlorocyclohexane (β-HCH) were detected at concentrations over 1 μg/g lipid in both tissues of some specimens. For most of the dioxin-like congeners, total PCBs, p,p′-DDE, oxychlordane, α- and β-HCH, hexachlorobenzene (HCB), and tris(4-chlorophenyl)methane (TCPMe), age-dependent increases in concentrations were found in the adipose tissue of males. No such age-dependent trend was observed in the liver, suggesting that there are different mechanisms underlying the hepatic concentrations of OCs. Immunoblot analyses indicated detectable expression of hepatic CYP1A2 protein, whereas no CYP1A1 protein was detected. The CYP1A2 expression levels were positively correlated with concentrations (on wet weight basis) of 2,3,4,7,8-P₅CDF, the dominant TEQ-contributed congeners in the liver, indicating the induction of this CYP. Hepatic CYP1A2 protein levels were strongly correlated with the liver to adipose concentration (L/A) ratios of PCDD/F congeners with more than 5 chlorine atoms. Together with higher concentrations of the congeners in the liver than in the adipose tissue, the observation on L/A ratios of highly chlorinated PCDD/Fs suggests that induced hepatic CYP1A2 protein is involved in their sequestration in this human population, as observed in model animals (rodents). Nonetheless, the magnitude of hepatic sequestration (L/A ratio) of PCDD/Fs in this human population was lower than in other mammals and birds, reported previously. This study emphasizes the fact that toxicokinetics of some OCs can be affected at least partly by CYP1A2 protein levels in humans. For the extrapolation of their toxicokinetics from model animals to humans, knowledge on the induction and sequestration potencies of CYP1A is necessary.     

Dietary intake of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) from fish and meat by residents of Nanjing,China

Concentrations of 14 polybrominated diphenyl ether (PBDEs) and 28 polychlorinated biphenyl (PCBs) congers were measured in 137 samples of fish and meat from Nanjing, a city in the Yangtze River Delta, China. Total concentrations of PBDEs were less in fish (mean of 180 pg/g ww; range 8.0–1100 pg/g ww), but more in non fish foods (mean of 180 pg/g ww; range 15–950 pg/g ww) than those reported from other countries. The total dietary intake of PBDEs and PCBs by humans were 9.9 ng PBDE/d and 870 ng PCB/d, respectively. The daily intake by a 60 kg adult of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQ_WHO) from PCBs was estimated to be 49 pg ^PCBTEQ_WHO/d (0.82 pg ^PCBTEQ_WHO/kg bw), which is less than the tolerable daily intake suggested by the World Health Organization (WHO). The daily intake of meat and fish accounted for 57.2% and 42.8% of the total intake of ^PCBTEQ_WHO.     

Global DNA hypermethylation is associated with high serum levels of persistent organic pollutants in an elderly population

Dioxin exposure has experimentally been associated with changes in DNA methylation, an epigenetic change that is associated with disease. The present study aims to investigate if serum levels of dioxin and other persistent environmental pollutants are related to global DNA methylation in a human sample. In the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study (all aged 70), global DNA methylation was measured by the Luminometric Methylation Assay in 524 subjects. Twenty-three different POPs, including 16 PCBs, five pesticides, one dioxin (OCDD) and one brominated flame retardant (BDE47) were analysed by HRGC/HRMS. Ten single nucleotide polymorphisms (SNPs) in the Aryl hydrocarbon (Ah)-receptor were analysed by mini-sequencing. High levels of toxic equivalency (TEQ) for PCBs and dioxin were associated with DNA hypermethylation (p = 0.030). This was mainly attributed to coplanar non-ortho PCBs. While no significant associations were found between DNA methylation and SNPs in the Ah-receptor, an interaction was found between the SNP rs2237297 and TEQ so that TEQ was associated with hypermethylation (p = 0.009) only in subjects with one G-allele (n = 103). Also high levels of the PCB126 congener, the OCDD, and the pesticide metabolite p,p′-DDE were related to DNA hypermethylation (p = 0.01, 0.03 and 0.003, respectively). In conclusion, in a sample of elderly subjects, high TEQ including PCBs and the dioxin OCDD and high serum levels of PCB126, OCDD, and p,p′-DDE were related to global DNA hypermethylation in a cross-sectional analysis.     

Polybrominated diphenyl ethers (PBDEs) in marine mammals from Arctic and North Atlantic regions, 1986–2009

A selection of PBDE congeners was analyzed in pooled blubber samples of pilot whale (Globicephala melas), ringed seal (Phoca hispida), minke whale (Balaenoptera acutorostrata), fin whale (Balaenoptera physalus), harbor porpoise (Phocoena phocoena), hooded seal (Cystophora cristata) and Atlantic white-sided dolphin (Lagenorhynchus acutus), covering a time period of more than 20 years (1986–2009). The analytes were extracted and cleaned-up using open column extraction and multi-layer silica gel column chromatography, and the analysis was performed on a GC-MS system operating in the NCI mode. The highest PBDE levels were found in the toothed whale species pilot whale and white-sided dolphin, and the lowest levels in fin whales and ringed seals. One-sided analyses of variance (ANOVA) followed by Tukey comparisons of means were applied to test for differences between years and sampling areas. Due to inter-year sampling variability, only general comparisons of PBDE concentrations between different sampling areas could be made. Differences in PBDE concentrations between three sampling periods, from 1986 to 2007, were evaluated in samples of pilot whales, ringed seals, white-sided dolphins and hooded seals. The highest PBDE levels were found in samples from the late 1990s or beginning of 2000, possibly reflecting the increase in the global production of technical PBDE mixtures in the 1990s. The levels of BDE #153 and #154 increased relative to the total PBDE concentration in some of the species in recent years, which may indicate an increased relative exposure to higher brominated congeners. In order to assess the effect of measures taken in legally binding international agreements, it is important to continuously monitor POPs such as PBDEs in sub-Arctic and Arctic environments.     

A study of diesel emissions on Drosophila

A sex-linked recessive lethal test was performed on male fruit flies of the species Drosophila melanogaster, (Oregon-R strain), exposed to an approximate five-fold dilution of exhaust from a diesel engine. The eight hour exposure was achieved by drawing diluted diesel exhaust from a three cubic meter stainless steel exposure chamber housing laboratory animals through a two liter reaction flask modified for use with Drosophila. A preconditioned sampling bag was used to collect the emissions after passing through the exposure chamber containing the flies. Results of analyses performed on the diesel exhaust mixture showed the following: carbon dioxide—0.17%, carbon monoxide—12.2 ppm, hydrocarbons—11.6 ppm, nitrogen oxide—3.8 ppm, nitrogen dioxide—2.9 ppm, sulphur dioxide—1.0 ppm, and particulates—2.18 mg/m³. Two broods of the F₂ generation were investigated for the occurrence of recessive lethal events. These broods approximated the developing gametogenic stages of mature sperm (P₁ matings on days 2 and 3 postexposure) and spermatocytes (P₁ matings on days 8 and 9). Additionally, the F₃ generation was evaluated for the occurrence of mosaic recessive lethal events which might escape detection in the F₂ generation. An equal number of F₂ and F₃ flies for both broods served as concurrent controls. Results indicate that, under the conditions tested, the diesel exhaust did not increase the mutation frequency of the exposed flies (F₂ rate = 0.30%, F₃ rate = 0%) when compared to the concurrent controls (F₂ rate = 0.37%, F₃ rate = 0.15%).     

Bearing Witness? Polar Bears as Icons for Climate Change Communication in National Geographic

This article investigates how polar bears were established as icons of climate change in the popular science magazine National Geographic. In a multistep process, anthropomorphized depictions first established polar bears as subjects of identification. Then, polar bears were visually connected to the endangered Arctic. Finally, they emerged as ambassadors of a threatened ecosystem and icons of climate change. I highlight the wider political contexts of this process of iconization and the semiotic and cultural resources on which it draws, showing what kind of climate change communication the polar bear icon enables or inhibits. The icon lends itself to being deployed in visual communication strategies creating personal concern and public awareness for climate change. At the same time, the icon fosters an individualized, emotionalized, and localized account of climate change but does not make its wider causes visible.     

The bioaccessibility of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) in cooked plant and animal origin foods

In this study, we compared the effect of boiling and frying food preparation methods in determining the bioaccessibility of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) in rice, cabbage, milk powder, eggs, beef, and fresh water fish. We then used these data to calculate a toxic equivalent (TEQ) for risk assessment and compared it to published values that did not account for bioaccessibility.When the foods were prepared by boiling, the mean bioaccessibility (%) in rice (PCBs: 16.5 ± 1.0, PCDD/Fs: 4.9 ± 0.3) and cabbage (PCBs: 4.2 ± 0.9, PCDD/Fs: 1.9 ± 0.7) were lower than in animal origin foods (beef, PCBs: 49.0 ± 3.3, PCDD/Fs: 7.8 ± 0.9; egg, PCBs: 29.7 ± 3.1, PCDD/Fs: 8.6 ± 1.3; fish, PCBs: 26.9 ± 2.5, PCDD/Fs: 7.9 ± 1.3; milk powder, PCBs: 72.3 ± 1.6, PCDD/Fs: 28.4 ± 1.2).When fried in cooking oil, the bioaccessibilities of all analytes in all foods increased, but the increase in plant based foods (rice, PCBs: 3.4 ×, PCDD/Fs: 3.6 ×; cabbage, PCBs: 10.3 ×, PCDD/Fs: 7.9 ×) was greater than that of animal origin foods (beef, PCBs: 1.6 ×, PCDD/Fs: 3.4 ×; egg, PCBs: 2.1 ×, PCDD/Fs: 1.8 ×; fish, PCBs: 2.8, PCDD/Fs: 3.2 ×).Comparison of PCBs/PCDD/Fs bioaccessibility in rice and cabbage showed that bioaccessibility was greater in the low fat, high carbohydrate/protein content food (rice) than in the low carbohydrate/protein, low fat content food (cabbage), regardless of the method used to prepare the food.Adjusting for bioaccessibility reduced the gross estimated daily intake (EDI) of 112 pg WHO-TEQ/day, by 88% and 63% respectively for foods prepared by boiling and frying.Our results indicate that: 1) The method used for cooking is an important determinant of PCBs/PCDD/Fs bioaccessibility, especially for plant origin foods, 2) there might be a joint fat, carbohydrate and protein effect that influences the bioaccessibilities of PCBs/PCDD/Fs in foods, and 3) use of bioaccessibility estimates would reduce the uncertainty in TEQ calculations.     

Three decades (1983–2010) of contaminant trends in East Greenland polar bears (Ursus maritimus). Part 1: Legacy organochlorine contaminants

Legacy organochlorine contaminants were determined in adipose tissues from 294 polar bears (Ursus maritimus) sampled in East Greenland in 23 of the 28 years between 1983 and 2010. Of 19 major legacy contaminants and congeners (ΣPCB, 4 PCB congeners (CB153, 180, 170/190), ΣDDT, p,p′-DDE, p,p′ -DDD and p,p′-DDT, α- and β-hexachlorocyclohexane (HCH), HCB, octachlorostyrene, dieldrin, oxychlordane, cis- and trans-chlordane, cis- and trans-nonachlor, heptachlor epoxide and BB-153), 18 showed statistically significant average yearly declines of − 4.4% (range: − 2.0 to − 10.8%/year) among subadult polar bears (i.e. females < 5 years, males < 6 years). For example, the ∑ PCB concentrations declined 2.7 fold from 22 730 ng/g lw (95% C.I.: 12 470–32 990 ng/g lw) in 1983–1986 to 8473 ng/g lw (95% C.I.: 6369–9776 ng/g lw) in 2006–2010. Similar but fewer statistically significant trends were found for adult females and adult males likely due to smaller sample size and years. Despite declines as a result of international regulations, relatively high levels of these historic pollutants persist in East Greenland polar bear tissues.     

Measuring environmental stress in East Greenland polar bears, 1892–1927 and 1988–2009: What does hair cortisol tell us?

Hair sampled from 96 East Greenland polar bears (Ursus maritimus) over the periods 1892–1927 and 1988–2009 was analyzed for cortisol as a proxy to investigate temporal patterns of environmental stress. Cortisol concentration was independent of sex and age, and was found at significantly higher (p < 0.001) concentrations in historical hair samples (1892–1927; n = 8) relative to recent ones (1988–2009; n = 88). In addition, there was a linear time trend in cortisol concentration of the recent samples (p < 0.01), with an annual decrease of 2.7%. The recent hair samples were also analyzed for major bioaccumulative, persistent organic pollutants (POPs). There were no obvious POP related time trends or correlations between hair cortisol and hair POP concentrations. Thus, polar bear hair appears to be a relatively poor indicator of the animal's general POP load in adipose tissue. However, further investigations are warranted to explore the reasons for the temporal decrease found in the bears' hair cortisol levels.     

Development and validation of prediction models for blood concentrations of dioxins and PCBs using dietary intakes

BackgroundDioxins and PCBs accumulate in the food chain and might exert toxic effects in animals and humans. In large epidemiologic studies, exposure estimates of these compounds based on analyses of biological material might not be available or affordable.ObjectivesTo develop and then validate models for predicting concentrations of dioxins and PCBs in blood using a comprehensive food frequency questionnaire and blood concentrations.MethodsPrediction models were built on data from one study (n = 195), and validated in an independent study group (n = 66). We used linear regression to develop predictive models for dioxins and PCBs, both sums of congeners and 33 single congeners (7 and 10 polychlorinated dibenzo-p-dioxins and furans (PCDDs/PCDFs), 12 dioxin-like polychlorinated biphenyls (PCBs: 4 non-ortho and 8 mono-ortho), sum of all the 29 dioxin-like compounds (total TEQ) and sum of 4 non dioxin-like PCBs (∑ CB-101, 138, 153, 183 = PCB₄). We used the blood concentration and dietary intake of each of the above as dependent and independent variables, while sex, parity, age, place of living, smoking status, energy intake and education were covariates. We validated the models in a new study population comparing the predicted blood concentrations with the measured blood concentrations using correlation coefficients and Weighted Kappa (К_W) as measures of agreement, considering К_W > 0.40 as successful prediction.ResultsThe models explained 78% (sum dioxin-like compounds), 76% (PCDDs), 76% (PCDFs), 74% (no-PCBs), 69% (mo-PCBs), 68% (PCB₄) and 63% (CB-153) of the variance. In addition to dietary intake, age and sex were the most important covariates.The predicted blood concentrations were highly correlated with the measured values, with r = 0.75 for dl-compounds 0.70 for PCB₄, (p < 0.001) and 0.66 (p < 0.001) for CB-153. К_W was 0.68 for sum dl-compounds 0.65 for both PCB₄ and CB-153. Out of 33 congeners 16 (13 dl-compounds and 3 ndl PCBs) had К_W > 0.40.ConclusionsThe models developed had high power to predict blood levels of dioxins and PCBs and to correctly rank subjects according to high or low exposure based on dietary intake and demographic information. These models underline the value of dietary intake data for use in investigations of associations between dioxin and PCB exposure and health outcomes in large epidemiological studies with limited biomaterial for chemical analysis.     

Background exposure to persistent organic pollutants predicts stroke in the elderly

Background exposure to persistent organic pollutants (POPs), lipophilic xenobiotics that accumulate mainly in adipose tissue, has recently emerged as a new risk factor for cardiovascular diseases. This prospective study was performed to evaluate if plasma concentrations of selected POPs predict incident stroke among the elderly. Twenty‐one POPs (including 16 polychlorinated biphenyl (PCB) congeners, 3 organochlorine (OC) pesticides, 1 brominated diphenyl ether (BDE), and 1 dioxin) were measured in plasma collected at baseline in 898 participants aged 70 years of the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS). Stroke diagnosis was validated by hospital records. During the five year follow-up, 35 subjects developed hospital-treated stroke. After adjusting for known stroke risk factors, most PCBs with 4, 5, or 6 chlorine atoms, p,p′-DDE, trans-nonachlor, and octachlorodibenzo-p-dioxin significantly predicted the risk of stroke. Across quartiles of summary measures of PCBs and OC pesticides, the adjusted ORs were 1.0, 0.8 (95% confidence interval: 0.2–2.5), 1.2 (0.4–3.4), and 2.1 (0.7–6.2) for PCBs and 1.0, 1.2 (0.3–4.2), 2.3 (0.7–6.9), and 3.0 (1.0–9.4) for OC pesticides (P for trend = 0.11 and 0.03, respectively). The adjusted ORs among participants ≥ 90th percentile of the summary measures were 5.5 (1.7–18.1) for PCBs and 4.0 (1.1–14.6) for OC pesticides; corresponding ORs for those ≥ 95th percentile were 7.8 (2.1–29.6) and 9.5 (2.3–38.9). Background exposure to POPs may play an important role in development or progression of stroke in the elderly.     

Characterization of DDT in factory effluent by thin-layer chromatography

Thin-layer chromatography (TLC) is shown as an effective, inexpensive, reliable, and less time consuming technique for simple and effective monitoring of persistent toxicant-like DDT in its manufacturing plant effluent. Aqueous untreated and treated grab and composit effluent samples were collected, extracted with a solvent and concentrated and chromatographed both for qualitative and quantitative analysis for p, p′-DDT and related compounds. This technique was successful and can form an effective, inexpensive method to be used by the developing countries, which have limited financial resources.