PCDD/F and PCB concentrations in Arctic ringed seals (Phoca hispida) have not changed between 1981 and 2000

PCDD/Fs and DL-PCBs in Chinese Mitten Crab (Eriocheir sinensis) and Its Farming Environment in Shanghai, China

Most polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in the human body are acquired from dietary intake. The chronic exposure of humans to PCDD/Fs and DL-PCBs is a major health concern, and these compounds are strictly controlled in many areas. This study measured the levels of PCDD/Fs and DL-PCBs in Chinese mitten crab (Eriocheir sinensis) farms in Shanghai and determined potential sources. The mean concentrations of PCDD/Fs and DL-PCBs in the studied crab samples were 264.20 ± 260.14 and 506.25 ± 226.80 pg/g ww (wet weight), respectively. The range of the toxic equivalent (TEQ) for the total PCDD/Fs and DL-PCBs in the crab samples was 1.20–29.04 pg TEQ/g ww. Further analysis revealed that the TEQ input to crabs in aquacultural water was 1.6 times higher than the TEQ in edible crab parts. Aquatic plants, shore plants, and feed contributed about 0.05% of the total TEQ input to crabs. The TEQ contribution from sediment was 317 times that found in edible crab parts, and sediment may be the most prevalent source of PCDD/Fs and DL-PCBs in farm crabs. The evaluation of the Shanghai market crab revealed different levels of PCDD/Fs and DL-PCBs. The TEQs for the mean PCDD/F and DL-PCB levels were 1.55 ± 1.96 and 1.05 ± 0.55 pg TEQ/g ww, respectively. The tolerable daily intake (TDI) levels of adults and children were lower than the prescribed range (1–4 pg TEQ/kg (weight)·d), indicating no significant chronic or acute ingestion risk for adults and children.

Unintentionally produced polychlorinated biphenyls in pigments: An updated review on their formation, emission sources, contamination status, and toxic effects

The formation, emission, environmental occurrence, and potential adverse effects of unintentionally produced polychlorinated biphenyls (PCBs) in pigments are reviewed, providing a comprehensive and up-to-date picture on these pollutants. PCBs are typically formed during manufacturing of organic pigments that involve chlorinated intermediates and reaction solvents, rather than those of inorganic pigments. Concentrations and profiles of PCBs vary greatly among pigment types and producers, with total PCB levels ranging from lower than detection limits to several hundred ppm; major components can be low-chlorinated (e.g., CB-11) or high-chlorinated congeners (e.g., CB-209). Pigment-derived PCBs can be released into the environment through different steps including pigment production, application, and disposal. They can contaminate atmospheric, terrestrial, and aquatic ecosystems, and then affect organisms living there. This situation garners scientific and public attention to nonlegacy emissions of PCBs and suggests the need for appropriate monitoring, management, and abatement strategies regarding these pollutants.

Trends of persistent organic pollutants in ringed seals (Phoca hispida) from the Canadian Arctic

Ringed seals (Phoca hispida) have been used as bioindicator species of environmental contamination in Canada since the 1970s. In the present study, seals were harvested during subsistence hunts in four regions of the Canadian Arctic: Beaufort Sea, Arctic Archipelago, Hudson Bay, and coastal Labrador. An extensive suite of persistent organic pollutants (POPs) was determined in seal blubber collected for multiple years between 1972 and 2016. Results from this long-term study indicate geographical differences in the contaminant concentrations in seals and the significant general decrease of most POPs, including polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and related compounds, chlordanes (CHL), and hexachlorocyclohexanes (HCH) over time in ringed seals. The highest decrease rates (up to -9.1%/year for α-HCH) were found in seals from the Hudson Bay region where all chemicals investigated have significantly decreased since 1986. Significant increases in concentrations of hexachlorobenzene (HCB) in seals from Labrador and β-HCH in Sachs Harbour, NT and Arctic Archipelago were observed. Site-specific and contaminant-specific associations between climate pattern (i.e., Arctic Oscillation, North Atlantic Oscillation, and Pacific/North American pattern) and mean ice-coverage (total, first-year ice, and old-ice) were found at sites with the longest time trend data (i.e., Arviat, Sachs Harbour/Ulukhaktok and Resolute Bay). Overall, results suggest that North American and international regulations have led to the long-term reduction of most POPs in Canadian Arctic ringed seals by reducing emissions from primary sources. However, other sources of legacy compounds (e.g., environmental reservoirs) as well changes in food web composition and structure in relation to climate changes could also be influencing the very slow rates of decline, or stable levels, of contaminants found in seals at some sites. Further work is warranted to discern between co-variation of climate changes and contaminant concentrations and cause-and-effect relationships.

Declining trends of polychlorinated dibenzo-p-dioxins, dibenzofurans and non-ortho PCBs in Canadian Arctic seabirds

Polychorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (PCBs) such as the non-ortho PCBs (nPCBs) persist in the environment despite international measures to ban their emissions. We determined congener patterns and temporal trends for PCDDs, PCDFs, nPCBs as well as their toxic equivalents (TEQs) in eggs of thick-billed murres (Uria lomvia) and northern fulmars (Fulmarus glacialis) sampled from Prince Leopold Island in the Canadian Arctic between 1975 and 2014. The dominant PCDD congeners were 1,2,3,7,8-PnCDD, 2,3,7,8-TCDD and 1,2,3,6,7,8-HxCDD, and the dominant PCDF congener was 2,3,4,7,8-PnCDF. The nPCB profile was dominated by PCB-126. The TEQ profile in the murre eggs was dominated by nPCB-TEQ whereas in the fulmar eggs, the PCDF-TEQ contribution to ΣTEQ was slightly greater than that of nPCB-TEQ. Concentrations of ΣPCDD, ΣPCDF, ΣnPCB and ΣTEQ declined between 1975 and 2014 in both murre and fulmar eggs. Based on TEQ thresholds in the literature for other species, and taking into account the trend towards declining TEQ levels, it is unlikely that current levels of PCDDs, PCDFs or nPCBs are affecting the reproductive success of thick-billed murres or northern fulmars in the Canadian Arctic.

Chaotic time series prediction for prenatal exposure to polychlorinated biphenyls in umbilical cord blood using the least squares SEATR model

Chaotic time series prediction based on nonlinear systems showed a superior performance in prediction field. We studied prenatal exposure to polychlorinated biphenyls (PCBs) by chaotic time series prediction using the least squares self-exciting threshold autoregressive (SEATR) model in umbilical cord blood in an electronic waste (e-waste) contaminated area. The specific prediction steps basing on the proposal methods for prenatal PCB exposure were put forward, and the proposed scheme's validity was further verified by numerical simulation experiments. Experiment results show: 1) seven kinds of PCB congeners negatively correlate with five different indices for birth status: newborn weight, height, gestational age, Apgar score and anogenital distance; 2) prenatal PCB exposed group at greater risks compared to the reference group; 3) PCBs increasingly accumulated with time in newborns; and 4) the possibility of newborns suffering from related diseases in the future was greater. The desirable numerical simulation experiments results demonstrated the feasibility of applying mathematical model in the environmental toxicology field.

Satellite telemetry informs PCB source apportionment in a mobile, high trophic level marine mammal: the ringed seal (Pusa hispida)

Marine mammals are typically poor indicators of point sources of environmental contaminants as a consequence of their often complex feeding ecologies and extensive movements, all of which mask the contributions of specific inputs. The release of polychlorinated biphenyls (PCBs) by a military radar station into Saglek Bay, Labrador (Canada) has contaminated marine sediments, bottom-feeding fish, seabirds, and some ringed seals, but attributing the PCBs in the latter highly mobile animals to this source is exceedingly difficult. In addition to the application of such tools as stable isotopes (δ(15)N and δ(13)C) and univariate and multivariate statistical exploration of contaminant patterns and ratios, we used satellite telemetry to track the movements of 13 seals in their transient use of different feeding areas. Reduced size of home range and core area (i.e., areas of concentrated use), as well as increased time in coastal inlets, were important determinants of increased PCB concentrations in seals reflecting the contribution of Saglek Bay. Seals were classified into the same feeding groups using both space use and their contaminant burdens 85% of the time, highlighting the link between feeding ecology and exposure to PCBs. While the PCB source at Saglek provided a strong local signal in a remote environment, this first use of satellite telemetry demonstrates the utility of evaluating space-use strategies to better understand contaminant exposure, and more specifically the contribution of contaminant hotspots to mobile predators.

PCB related effects thresholds as derived through gene transcript profiles in locally contaminated ringed seals (Pusa hispida)

Causal evidence linking toxic injury to polychlorinated biphenyl (PCB) exposure is typically confounded by the complexity of real-world contaminant mixtures to which aquatic wildlife are exposed. A local PCB "hotspot" on the Labrador coast provided a rare opportunity to evaluate the effects of PCBs on the health of a marine mammal as this chemical dominated their persistent organic pollutant (POP) burdens. The release of approximately 260 kg of PCBs by a military radar facility over a 30 year period (1970-2000) contaminated some local marine biota, including the ringed seal (Pusa hispida). The abundance profiles of eight health-related gene transcripts were evaluated in liver samples collected from 43 ringed seals in the affected area. The mRNA transcript levels of five gene targets, including aryl hydrocarbon receptor (Ahr), interleukin-1 β (Il1b), estrogen receptor α (Esr1), insulin like growth factor receptor 1 (Igf1), and glucocorticoid receptor α (Nr3c1) correlated with increasing levels of blubber PCBs. PCB threshold values calculated using best-fit hockey-stick regression models for these five genes averaged 1,680±206 ng/g lw, with the lowest, most conservative, being 1,370 ng/g lw for Il1b. Approximately 14% of the seals in the region exceeded this threshold. The dominance of PCBs in the seals studied enabled an assessment of the effects of this chemical on gene transcripts involved in regulating the health of a highly mobile predator, something that is rarely possible in the world of complex mixtures.

Polychlorinated biphenyl profiles in ringed seals (Pusa Hispida) reveal historical contamination by a military radar station in Labrador, Canada

Significant amounts of soil contaminated with polychlorinated biphenyls (PCBs) were discovered at a military radar station in Saglek Bay, Labrador, Canada, in 1996. Subsequent work showed elevated PCB concentrations in local marine sediments, in the benthic-associated food web, and in some ringed seals (Pusa hispida). The benthic-associated food web clearly reflected local PCB contamination, but the high PCB concentrations found in some ringed seals remained unexplained. In the present study, the authors assess the extent to which this local PCB source at Saglek Bay is contributing to the contamination of ringed seals in northern Labrador. Among 63 ringed seals sampled along the northern Labrador coast, 5 (8%) had PCB levels that were higher than recorded anywhere else in the Canadian Arctic. In addition, compared with seals exhibiting a long-range signal, 45% and 60% of subadults and adult males, respectively, exhibited heavier PCB congener profiles as characterized by principal components analysis, >1.6-fold higher PCB/organochlorine pesticides ratios, and higher PCB concentration-weighted average log octanol-water partition coefficient values, consistent with a local source. Despite the spatially confined nature of contaminated sediments in Saglek Bay, the influence of this PCB source is not inconsequential; PCB concentrations in locally contaminated adult males are 2-fold higher than concentrations in those exposed only to long-range PCB sources and exceed an established threshold of 1.3 mg/kg for adverse health effects in seals.

Maternal-to-fetal transfer and concentration profiles of PCB congeners for Steller sea lions (Eumetopias jubatus) from Hokkaido, Japan

The concentrations of PCB congeners in the blubber and liver of mother Steller sea lions (Eumetopias jubatus; SSLs) and their fetuses from the coast of Hokkaido, Japan in 2008, 2010 and 2012 were analyzed by HRGC-HRMS, in order to elucidate PCB congener profiles and maternal-to-fetal transfer of PCBs in SSLs. ΣPCBs in the fetuses were 1400 ± 660 (the mean ± SD) ng/g-fat in the blubber and 570 ± 320 ng/g-fat in the liver, respectively. There was a concern that SSLs had been contaminated by PCBs during the fetal period. The concentrations of the major congeners in the blubber and liver were a correlation between the fetus and mother (blubber: r=0.9934, liver: r=0.9160; P ≦ 0.05). The results indicated that PCBs in the fetuses came from the mothers. #177 and #199 showed no correlations between the fetus and the mother in the blubber and liver. This indicated a selective capture by some natural protector such as the placenta.

Temporal trends in "legacy" organochlorine contaminants in blubber of ringed seals (Phoca hispida) from Ulukhaktok, NT, Canada between 1972 and 2010

In blubber of ringed seals (Phoca hispida) from Ulukhaktok, NT, residues of DDT, other organochlorine pesticides, and PCBs declined between 1972 and 2010. The rate of decline varied: concentrations of the DDT-group began to fall after 1981, whereas those of PCBs fell rapidly between 1972 and 1981, and then slowed. Concentrations of cis- and trans-chlordane and of HCB in both sexes, and of cis-nonachlor in males, declined slowly between 1978 and 2010; those of other organochlorine pesticides remained steady. Exponential half-lives of p,p'-DDT and p,p'-DDE in female seals are about 9 and 36 y (corresponding to initial declines of 7.8% and 1.9% per year, respectively) and those of PCB congeners from about 20 to 60 y (declines of 3.2% to <1.5% per year); the more refractory residues may be detectable for centuries to come. Exploratory PCA of PCB congener distribution identified temporal changes apparently not related to molecular structure.

Persistent organic pollutants in ringed seals from the Russian Arctic

Organochlorine compounds total DDT (ΣDDT), total HCH isomers (ΣHCH), toxaphenes (sum of Parlar 26, 50, 62), mirex, endrin, methoxychlor, total chlorinated benzenes (ΣCBz), total chlordane compounds (ΣCHL), polychlorinated biphenyls (total of 56 congeners; ΣPCBs), polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), and polybrominated diphenyl ethers (sum of 7 tri- to hepta congeners; ΣPBDEs) were analysed in the blubber of adult ringed seals from the four areas of the Russian Arctic (White Sea, Barents Sea, Kara Sea and Chukchi Sea) collected in 2001-2005. Ringed seals from the south-western part of the Kara Sea (Dikson Island - Yenisei estuary) were the most contaminated with ΣDDTs, ΣPCBs, ΣCHL, and mirex as compared with those found in the other three areas of Russian Arctic, while the highest mean concentrations of ΣHCHs and PCDD/Fs were found in the blubber of ringed seals from the Chukchi Sea and the White Sea, respectively. Among all organochlorine compounds measured in ringed seals from the European part of the Russian Arctic, concentrations of ΣDDT and ΣPCBs only were higher as compared with the other Arctic regions. Levels of all other organochlorine compounds were similar or lower than in seals from Svalbard, Alaska, the Canadian Arctic and Greenland. ΣPBDEs were found in all ringed seal samples analysed. There were no significant differences between ΣPBDE concentrations found in the blubber of ringed seals from the three studied areas of the European part of the Russian Arctic, while PBDE contamination level in ringed seals from the Chukchi Sea was 30-50 times lower. ΣPBDE levels in the blubber of seals from the European part of the Russian Arctic are slightly higher than in ringed seals from the Canadian Arctic, Alaska, and western Greenland but lower compared to ringed seals from Svalbard and eastern Greenland.

Temporal trends of legacy POPs in Arctic biota, an update

A statistically robust method was applied to 316 time-series of 'legacy' persistent organic pollutants (POPs) in Arctic biota from marine, freshwater and terrestrial ecosystems with the purpose of generating a 'meta-analysis' of temporal trend data collected over the past two to three decades for locations from Alaska in the west to northern Scandinavian in the east. Information from recently published temporal trend studies was tabulated and comparisons were also drawn with trends in arctic air. Most of the analysed time-series of legacy POP compounds showed decreasing trends, with only a few time-series showing significantly increasing trends. Compounds such as alpha-HCH, gamma-HCH and SigmaDDT had a relatively high proportion of time-series showing significantly decreasing trends; SigmaCHL had the lowest proportion. beta-HCH was an exception, where long-range transport through the ocean, and not the atmosphere, may explain several increasing trends that were detected in the Canadian Arctic. Moving east from the Canadian Arctic there was a trend towards a greater proportion of significantly decreasing trends. Several time-series for DDE and SigmaDDT showed significantly non-exponential trends, most often with a period of relative stability followed by a decrease. The median 'minimum detectable annual change within a 10-year period' for all of the time-series considered was 12% which did not meet the desirable level of statistical power capable of detecting a 5% annual change with a significance level of 5% within a 10-year period. The trends observed in the biota were consistent with decreasing trends of legacy POPs reported for Arctic air which appear to follow historic decreases in emissions. However, recent decreases in air are also starting to show signs of levelling off which may be an indication that atmospheric concentrations and, consequently those in the biota, are being less driven by primary sources and more by environmental processes and degradation.

History of Inuit community excretion of polychlorinated biphenyls recorded in sewage lake sediments

Exposure to polychlorinated biphenyls (PCBs) is high among the Inuit resulting from ingestion of contaminated wild "country" foods. These contaminants originate in urban/industrial areas and reach the Arctic by long-range atmospheric transport. Ingested PCBs eventually equilibrate into various body components, including feces, which become an indication of body burden. Bulk domestic sewage residue from a community will accumulate PCBs from feces; long-term accumulated sediments from a sewage treatment system are a historical indicator of changes in community-wide PCB excretion. In this study, sediment cores were collected from the domestic sewage treatment lake, known as Annak, for the Inuit Hamlet of Sanikiluaq, Canada (established 1967), and were dated (Pb-210, Cs-137) and analyzed for 127 PCB congeners. We focused our attention on the 47 congeners that were observed consistently. Atmospheric and local inputs to a nearby lake accounted for local background. PCB inputs from sewage grew rapidly from the late 1960s until 1990. The maximum 47 congener SigmaPCB excretion occurred in approximately 1989 (11116 ng person(-1)d(-1)); all sewage PCB inputs were dominated by PCB 153, PCB 138 and PCB 180. PCB ingestion from a Sanikiluaq food survey in 1989 for 11 of the most highly concentrated PCB congeners (7270 ng person(-1)d(-1)) was the same as our excretion estimate for the same congeners (7348 ng person(-1)d(-1)) that year, suggesting that by the late 1980s, the ingested amount of PCB was similar to what was excreted every day, although the latter is a reflection of body burden and not short-term exposure.

Contamination profiles of selected PCB congeners, chlorinated pesticides, PCDD/Fs in Antarctic fur seal pups and penguin eggs

The aim of this study was to investigate levels of some major environmental contaminants, such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and organochlorine pesticides in Antarctic samples. Concentrations of some persistent organic pollutants (POPs) were investigated in Antarctic fur seal pups and eggs of three species of penguins. Dichloro-diphenyl-trichloroethane (DDT) was the main pollutant, followed by PCBs; other organochlorine compounds such as hexachlorobenzene (HCB) and PCDD/Fs were usually found only in minor quantities. Adélie penguin eggs had significantly higher mean PCB concentrations (p<0.05) compared to the other two penguin species, but there was no difference in DDT levels (p>0.05). TEQ values in fur seal blubber in our study were one order of magnitude lower than those considered to elicit physiological effects in aquatic mammals. In general, POP concentrations in our samples suggested that likely the study populations were not currently at risk for adverse health effects, but indicated a clear need for further monitoring to assess the presence and time trend of a broad range of contaminants, mainly emerging POPs thought to be increasing in polar regions.

Accumulation features and temporal trends of PCDDs, PCDFs and PCBs in Baikal seals (Pusa sibirica)

This study investigated the accumulation features and temporal trends of PCDD/Fs, dioxin-like PCBs (DL-PCBs) and non-dioxin-like PCBs (NDL-PCBs) in the blubber of Baikal seals collected in 1992 and 2005. DL-PCBs (480-3600ng/g) and NDL-PCBs (980-35,000ng/g) were dominant contaminants. Concentrations of PCDDs and PCBs in males were significantly higher than in females. In males, age-dependent accumulation was observed for PCDDs, mono-ortho PCBs and NDL-PCBs. PCDFs and non-ortho PCBs showed no such trends, implying that exposure of seals to these contaminants has been decreasing in recent years. No decreasing temporal trend was observed for PCDDs, mono-ortho PCBs and NDL-PCBs, suggesting that Baikal seals are still exposed to PCDDs and PCBs. TEQs of PCDDs and mono-ortho PCBs in seals collected in 2005 accounted for 62-77% of total TEQs. The TEQ levels in 40% of the specimens exceeded the threshold level for immunosuppression observed in harbor seals (209pg/g).

Dioxins and PCBs in Greenland shark (Somniosus microcephalus) from the North-East Atlantic

The Greenland shark (Somniosus microcephalus) is a high-trophic fish species present in Arctic waters. The present study aimed to determine concentrations of polychlorinated dibenzo-p-dioxins and furans (PCDDs/Fs), dioxin-like (DL) PCBs and six non-dioxin-like (NDL) PCBs in muscle and liver from 10 female Greenland sharks collected between 2001 and 2003 from Icelandic waters. The mean total concentrations of PCDDs/Fs were 13 and 530pg/g fat for muscle and liver, respectively, and show enrichment in the liver. Concentrations of DL-non-ortho PCBs were also higher in liver compared to muscle with mean concentrations of 7.8 and 0.36ng/g fat, respectively. No enrichment in the liver was found for DL-mono-ortho- and NDL-PCBs. No correlation was found between the size range studied and total concentrations of the compounds analyzed. Total WHO-TEQs (PCDDs/Fs and DL-PCBs) ranged between 7.1-70 and 54-1500pg/g fat in muscle and liver, respectively.