Exposure and effects assessment of persistent organohalogen contaminants in arctic wildlife and fish

Impact of organic matter and meteorological factors on the long-term trend, seasonality, and gas/particle partitioning behavior of atmospheric PBDEs

We extended our knowledge of the impact of organic matter (OM) and meteorological factors on the long-term trend, seasonality and gas/particle partitioning behavior of polybrominated diphenyl ethers (PBDEs). In Lake Chaohu, PBDEs had an increasing trend, with a doubling time of 13.4 years at the urban site, and a decreasing trend, with a halving time of 6.1 years at the rural site. At the urban site, the negative association of OM with most congeners indicated that the graphene-like carbonaceous components might carry or release PBDEs, and the negative association of long-term rain fall and wind speed with most congeners was suggested to dilute or increase the transport speed of PBDEs in the atmosphere. At the rural site, the negative association with PM₁₀ and positive association with OM indicated that the PBDEs-buried OM was mainly from non-local sources. Restricted to the temperature seasonality, the frequency of PBDE congeners decreased with seasonality from 64% and 43% to 50% and 43% at the urban and rural sites, respectively. The slope of the simplified Pankow adsorption model in samples with larger absolute OM content (>10 μgC m^-3) was steeper than that with lower absolute OM content (<5 μgC m^-3), indicating that OM facilitated the gas-particle partitioning equilibrium. Interestingly, the theoretic partitioning coefficients were much lower than the measured ones for less brominated BDEs, whereas the highly brominated BDEs did the opposite. The theoretic partitioning coefficient should be further modified by considering the molecular weight distribution of the OM and the corresponding activity coefficients of the target compound in a specific type of OM phase.

Contamination of organohalogen chemicals and hepatic steatosis in common kingfisher (Alcedo atthis) breeding at a nature reserve near e-waste recycling sites in South China

Severe pollution of organohalogen compounds (OHCs) including PBDEs, PCBs and DDTs is demonstrated in e-waste recycling sites and metropolis in South China, but relatively little is known of their impacts on wildlife that inhabits nature reserves in this region, especially those located at the neighborhood areas of e-waste recycling sites. In the present study, PBDEs, PCBs and DDTs as well as liver histological changes were examined in common kingfisher breeding at a nature reserve (Shimentai National Nature Reserve, SNNR) near a notorious e-waste recycling site in South China. Mean ∑PBDEs (84.9 ng/g lipid weight), ∑PCBs (397 ng/g) and ∑TEQs (total toxic equivalent of coplanar PCBs, 2.68 ng/g) concentrations in kingfishers from SNNR were approximately 2-, 5-, and 4-fold higher than those detected in a reference population, respectively; suggesting contamination of the e-waste-derived OHCs in SNNR. Mean ∑DDTs concentration (2150 ng/g) in kingfishers from SNNR was also higher (~2-fold) than that from the reference samples. While ∑DDTs dominated the composition of the OHCs at both sampling sites, ∑PCBs was also important in kingfishers from SNNR, averaging 15% of ∑OHCs. Histological examination of the liver showed steatosis occurred in 60% of the kingfishers from SNNR. Birds with hepatic steatosis had significantly (p = 0.03) higher ∑TEQs than those without steatosis. Similar trends were also found for ∑PCBs and ∑DDTs, although it is not statistically significant. It therefore seems likely that the hepatic steatosis were associated with the relatively high body-burden of OHCs, although the possibility of other factors resulting in hepatic steatosis cannot be ruled out.

Practical advice for selecting or determining trophic magnification factors for application under the European Union Water Framework Directive

European Union Directive 2013/39/EU, which amended and updated the Water Framework Directive (WFD; 2000/60/EC) and its daughter directive (2008/105/EC), sets Environmental Quality Standards for biota (EQSbiota ) for a number of bioaccumulative chemicals. These chemicals pose a threat to both aquatic wildlife and human health via the consumption of contaminated prey or the intake of contaminated food originating from the aquatic environment. EU member states will need to establish programs to monitor the concentration of 11 priority substances in biota and assess compliance against these new standards for the classification of surface water bodies. An EU-wide guidance effectively addresses the implementation of EQSbiota . Flexibility is allowed in the choice of target species used for monitoring to account for both diversity of habitats and aquatic community composition across Europe. According to that guidance, the consistency and comparability of monitoring data across member states should be enhanced by adjusting the data on biota contaminant concentrations to a standard trophic level by use of the appropriate trophic magnification factor (TMF), a metric of contaminant biomagnification through the food web. In this context, the selection of a TMF value for a given substance is a critical issue, because this field-derived measure of trophic magnification can show variability related to the characteristics of ecosystems, the biology and ecology of organisms, the experimental design, and the statistical methods used for TMF calculation. This paper provides general practical advice and guidance for the selection or determination of TMFs for reliable application within the context of the WFD (i.e., adjustment of monitoring data and EQS derivation). Based on a series of quality attributes for TMFs, a decision tree is presented to help end users select a reasonable and relevant TMF. Integr Environ Assess Manag 2019;15:266-277. © 2018 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Contaminants in Atlantic walruses in Svalbard Part 2: Relationships with endocrine and immune systems

Marine mammals in the Barents Sea region have among the highest levels of contaminants recorded in the Arctic and the Atlantic walrus (Odobenus rosmarus rosmarus) is one of the most contaminated species within this region. We therefore investigated the relationships bewteen blubber concentrations of lipophilic persistent organic pollutants (POPs) and plasma concentrations of perfluoroalkyl substances (PFASs) and markers of endocrine and immune functions in adult male Atlantic walruses (n = 38) from Svalbard, Norway. To do so, we assessed plasma concentrations of five forms of thyroid hormones and transcript levels of genes related to the endocrine and immune systems as endpoints; transcript levels of seven genes in blubber and 23 genes in blood cells were studied. Results indicated that plasma total thyroxine (TT4) concentrations and ratio of TT4 and reverse triiodothyronine decreased with increasing blubber concentrations of lipophilic POPs. Blood cell transcript levels of genes involved in the function of T and B cells (FC like receptors 2 and 5, cytotoxic T-lymphocyte associated protein 4 and protein tyrosine phosphatase non-receptor type 22) were increased with plasma PFAS concentrations. These results suggest that changes in thyroid and immune systems in adult male walruses are linked to current levels of contaminant exposure.

Can variability in corticosterone levels be related to POPs and OPEs in feathers from nestling cinereous vultures (Aegypius monachus)?

Persistent organic pollutants (POPs) are still globally distributed and some have been shown to interact with the endocrine system of birds. However, the relationship between POPs and the stress response mediated by the hypothalamic-pituitary-adrenal (HPA) axis is still poorly understood. Raising concerns are now focused on the toxic properties of emergent organophosphate ester flame retardants (OPEs), but whether OPEs interact with the HPA axis response has not yet been investigated. We measured corticosterone concentrations in feathers (CORTf) as a long-term biomarker of the bird HPA axis response and we investigated their relationship with POP and OPE concentrations in down feathers of nestling cinereous vultures (Aegypius monachus). We also examined whether high contaminant burden and high CORTf concentrations impacted the duration of chick development. The most predominant compounds were the following: p,p'-DDE (3.28 ± 0.26 ng g^-1 dw) > γ-HCH (0.78 ± 0.09 ng g^-1 dw) > BDE-99 (0.73 ± 0.09 ng g^-1 dw) > CB-153 (0.67 ± 0.04 ng g^-1 dw). The most persistent POP compounds (CB-170, -177, -180, -183, -187, -194 and p,p'-DDE) were associated (P = 0.02) with high concentrations of CORTf (range: 0.55-6.09 pg mm^-1), while no relationship was found when OPEs were tested (P > 0.05). Later egg-laying was positively associated to high levels of CORTf (P = 0.02) and reduced duration of chick development (P < 0.001), suggesting a beneficial effect of the HPA axis response on the growth of the chicks. In addition, males with high concentrations of the most persistent POP compounds tended to show a reduced duration of the nestling period (P = 0.05) and an equal fledging success than chicks with lower levels. These findings suggest that POPs, but not OPEs, may interact with the HPA axis response of chicks, although levels were not high enough to cause detrimental consequences.

Assessment of organochlorine pesticides in the Himalayan riverine ecosystems from Pakistan using passive sampling techniques

Organochlorine pesticides (OCPs) pose a considerable threat to human and environmental health. Despite most OCPs have been banned, they are still reported to be used in developing countries, including Pakistan. We aimed to identify the distribution, origin, mobility, and potential risks from OCPs in three major environmental compartments, i.e., air, water, and soil, across Azad Jammu and Kashmir valley, Pakistan. The sums of OCPs ranged between 66 and 530 pg/g in soil, 5 and 13 pg/L in surface water, and 14 and 191 pg/m3 in air, respectively. The highest sum of OCPs was observed in the downstream zone of a river that was predominantly influenced by peri-urban and urban areas. The OCP isomers ratios (α-HCH/γ-HCH and o,p'-DDT/p,p'-DDT) indicate use of lindane and technical DDTs mixture as a source of HCH and DDT in the riverine environment. Similarly, the ratios of DDE and DDD/the sum of DDTs, α-endosulfan/β-endosulfan, and cis-chlordane/trans-chlordane indicate recent use of DDTs, endosulfan, and chlordane in the region. The air-water exchange fugacity ratios indicate net volatilization (fw/fa > 1) of α-endosulfan and trans-chlordane, and net deposition (fw/fa < 1) of β-endosulfan, α-HCH, γ-HCH p,p'-DDD, p,p'-DDE, and p,p'-DDT. Based on the risk quotient (RQ) method, we consider the acute ecological risks for fish associated with the levels of OCPs as negligible. However, more studies are recommended to evaluate the chronic ecological risks to other riverine-associated aquatic and terrestrial species as well as human health risks to the POPs exposure through food chain transfer in forthcoming years.

Temporal trends of persistent organic pollutants in Arctic marine and freshwater biota

More than 1000 time-series of persistent organic pollutants (POPs) in Arctic biota from marine and freshwater ecosystems some extending back to the beginning of 1980s were analyzed using a robust statistical method. The Arctic area encompassed extended from Alaska, USA in the west to northern Scandinavian in the east, with data gaps for Arctic Russia and Arctic Finland. The aim was to investigate whether temporal trends for different animal groups and matrices were consistent across a larger geographical area. In general, legacy POPs showed decreasing concentrations over the last two to three decades, which were most pronounced for α-HCH and least pronounced for HCB and β-HCH. Few time-series of legacy POPs showed increasing trends and only at sites suspected to be influenced by local source. The brominated flame retardant congener BDE-47 showed a typical trend of increasing concentration up to approximately the mid-2000s followed by a decreasing concentration. A similar trend was found for perfluorooctane sulfonic acid (PFOS). These trends are likely related to the relatively recent introduction of national and international controls of hexa- and hepta-BDE congeners and the voluntary phase-out of PFOS production in the USA in 2000. Hexabromocyclododecane (HBCDD) was the only compound in this study showing a consistent increasing trend. Only 12% of the long-term time-series were able to detect a 5% annual change with a statistical power of 80% at α < 0.05. The remaining 88% of time-series need additional years of data collection before fulfilling these statistical requirements. In the case of the organochlorine long-term time-series, 45% of these would require >20 years monitoring before this requirement would be fulfilled.

Development and Evaluation of a Combined Bioenergetics and Organic Chemical Mass-Balance Bioaccumulation Model for Fish

This study describes the development and evaluation of a new bioenergetically balanced bioaccumulation (3B) model for organic chemicals in fish. The 3B model is developed from a large database of routine metabolic (oxygen consumption) rates composed of a range of species, body mass, and temperatures. The chemical uptake and elimination rates of the 3B model are compared against those from three existing bioaccumulation models. A time-variant version of the 3B model is evaluated against measured concentrations of five polychlorinated biphenyls in different-size fish depurated over the course of a year, during which water temperature changed by 22 °C. The "generic" species 3B model predicts fish concentrations to within a factor of 3 of the measured data for the majority of observations ( n = 438) and outperforms a previously published "species-specific" bioenergetics model. Bioenergetics aspects of the 3B model are further evaluated by comparing predicted feeding rates and growth rates to measured rates obtained from diverse laboratory conditions ( n 572). While bioenergetics performance is acceptable, the 3B model seems to generally perform better when ingestion rates are calculated from growth rates rather than vice versa. For field applications, parametrization of the activity multiplier remains a key uncertainty underlying the bioenergetics calculations.

White-tailed eagle (Haliaeetus albicilla) feathers from Norway are suitable for monitoring of legacy, but not emerging contaminants

While feathers have been successfully validated for monitoring of internal concentrations of heavy metals and legacy persistent organic pollutants (POPs), less is known about their suitability for monitoring of emerging contaminants (ECs). Our study presents a broad investigation of both legacy POPs and ECs in non-destructive matrices from a bird of prey. Plasma and feathers were sampled in 2015 and 2016 from 70 whitetailed eagle (Haliaeetus albicilla) nestlings from two archipelagos in Norway. Preen oil was also sampled in 2016. Samples were analysed for POPs (polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorinated pesticides (OCPs)) and ECs (per- and polyfluoroalkyl substances (PFASs), dechlorane plus (DPs), phosphate and novel brominated flame retardants (PFRs and NBFRs)). A total of nine PCBs, three OCPs, one PBDE and one PFAS were detected in over 50% of the plasma and feather samples within each sampling year and location. Significant and positive correlations were found between plasma, feathers and preen oil concentrations of legacy POPs and confirm the findings of previous research on the usefulness of these matrices for non-destructive monitoring. In contrast, the suitability of feathers for ECs seems to be limited. Detection frequencies (DF) of PFASs were higher in plasma (mean DF: 78%) than in feathers (mean DF: 38%). Only perfluoroundecanoic acid could be quantified in over 50% of both plasma and feather samples, yet their correlation was poor and not significant. The detection frequencies of PFRs, NBFRs and DPs were very low in plasma (mean DF: 1-13%), compared to feathers (mean DF: 10-57%). This may suggest external atmospheric deposition, rapid internal biotransformation or excretion of these compounds. Accordingly, we suggest prioritising plasma for PFASs analyses, while the sources of PFRs, NBFRs and DPs in feathers and plasma need further investigation.

Concentrations of legacy and new contaminants are related to metabolite profiles in Hudson Bay polar bears

There are very few metabolomics assessments based on field accumulated, uncontrolled contaminant exposures in wildlife, particularly in the Arctic. In the present study, targeted metabolomics and contaminant data were analyzed together to assess potential influences of contaminant exposure on the hepatic metabolome of male polar bears (n = 29) from the southern and western Hudson Bay (SHB and WHB respectively), Canada. The 29 metabolites identified as important in the differentiation of the two subpopulations after partial least squares discriminant analysis (PLS-DA) included phosphatidylcholines (PCs), acylcarnitines (ACs; involved in β-oxidation of fatty acids), and the fatty acid (FA) arachidonic acid (ARA). Perfluorinated alkyl substances, polybrominated diphenyl ethers, dichlorodiphenyldichloroethylene (p,p'-DDE) and some highly chlorinated ortho-polychlorinated biphenyl congeners were greater in the SHB bears and were consistently inversely correlated with discriminating ACs and PCs between the subpopulations. The concentrations of discriminatory, legacy organochlorine pesticides along with one tetrachlorobiphenyl were greater in the WHB and were directly correlated with the VIP-identified ACs and PCs. ARA, glycerophospholipid and several amino acid metabolic pathways were identified as different between subpopulations and/or were impacted. ARA is an important, conditionally essential, dietary n-6 FA and is also part of the inflammation response, and elevated concentrations in the SHB could be related to differences in chronic contaminant exposure and/or differences in diet and/or season, among a number of possible explanations. Dietary tracers (stable isotopes of carbon and nitrogen) were correlated with some discriminatory metabolites, supporting the hypothesis that dietary variation was also an important factor in the differentiation of the subpopulations. The results suggest linkages between contaminant exposure in Hudson Bay polar bears and elements of the hepatic metabolome, particularly those related to lipid metabolism.

Mandibular shape in farmed Arctic foxes (Vulpes lagopus) exposed to persistent organic pollutants

We investigated if dietary exposure to persistent organic pollutants (POPs) affect mandibular asymmetry and periodontal disease in paired male-siblings of Arctic foxes (Vulpes lagopus). During ontogeny, one group of siblings was exposed to the complexed POP mixture in naturally contaminated minke whale (Balaenoptere acutorostarta) blubber (n = 10), while another group was given wet feed based on pig (Sus scrofa) fat as a control (n = 11). The ∑POP concentrations were 802 ng/g ww in the whale-based feed compared to 24 ng/g ww in the control diet. We conducted a two-dimensional geometric morphometric (GM) analysis of mandibular shape and asymmetry in the foxes and compared the two groups. The analyses showed that directional asymmetry was higher than fluctuating asymmetry in both groups and that mandibular shape differed significantly between the exposed and control group based on discriminant function analysis (T² = 58.52, p = 0.04, 1000 permutations). We also found a non-significantly higher incidence of periodontal disease (two-way ANOVA: p = 0.43) and greater severity of sub-canine alveolar bone deterioration similar to periodontitis (two-way ANOVA: p = 0.3) in the POP-exposed group. Based on these results, it is possible that dietary exposure to a complexed POP mixture lead to changes in jaw morphology in Arctic foxes. This study suggests that extrinsic factors, such as dietary exposure to POPs, may affect mandibular shape and health in a way that could be harmful to wild Arctic populations. Therefore, further studies using GM analysis as an alternative to traditional morphometric methods should be conducted for wild Arctic fox populations exposed to environmental contaminants.

Temporal trends of legacy organochlorines in eggs of Canadian Arctic seabirds monitored over four decades

We compared temporal trends of legacy organochlorine pesticides and PCBs in eggs of five seabird species breeding at Prince Leopold Island in the Canadian high Arctic. Concentrations of most of the major organochlorine groups/compounds have either declined (e.g. Σ₃₅PCB, ΣDDT, ΣCBz, ΣCHL, octachlorostyrene) or shown no consistent directional change (e.g. heptachlor epoxide) since 1975 in eggs of thick-billed murres (Uria lomvia), northern fulmars (Fulmarus glacialis) and black-legged kittiwakes (Rissa tridactyla). Aside from β-HCH, which increased in most species, the major organochlorine compounds either declined or showed no trend between 1993 and 2013 in eggs of five seabird species (thick-billed murre, northern fulmar, black-legged kittiwake, black guillemot Cepphus grylle, glaucous gull Larus hyperboreus). Most of the declines occurred during the 1970s to 1990s followed by little change during the 2000s. Glaucous gull eggs had the highest concentrations of almost all organochlorines in the five years compared (1993, 1998, 2003/04, 2008, 2013), and murre eggs generally had among the lowest concentrations. The primary organochlorines found in eggs of all five species were Σ₃₅PCB, ΣDDT (mainly p,p'-DDE), ΣCBz (mainly hexachlorobenzene) and ΣCHL (mainly oxychlordane) although proportions varied by species and year. The major PCB congeners found in eggs of all five species were CB-153, -138, -118 and -180. The penta-, hexa- and heptachlorobiphenyl homologs comprised the largest proportion of Σ₃₅PCB in all five species. Although levels of most legacy organochlorines have declined since 1975, the potential for climate change to alter chemical transport pathways as well as exposure pathways in the biotic environment could affect temporal trends. Therefore, it is important to continue to monitor these legacy contaminants in order to determine how these changes will affect the temporal trends observed to date.

Contaminants in Atlantic walruses in Svalbard part 1: Relationships between exposure, diet and pathogen prevalence

This study investigated relationships between organohalogen compound (OHC) exposure, feeding habits, and pathogen exposure in a recovering population of Atlantic walruses (Odobenus rosmarus rosmarus) from the Svalbard Archipelago, Norway. Various samples were collected from 39 free-living, apparently healthy, adult male walruses immobilised at three sampling locations during the summers of 2014 and 2015. Concentrations of lipophilic compounds (polychlorinated biphenyls, organochlorine pesticides and polybrominated diphenyl ethers) were analysed in blubber samples, and concentrations of perfluoroalkylated substances (PFASs) were determined in plasma samples. Stable isotopes of carbon and nitrogen were measured in seven tissue types and surveys for three infectious pathogens were conducted. Despite an overall decline in lipophilic compound concentrations since this population was last studied (2006), the contaminant pattern was similar, including extremely large inter-individual variation. Stable isotope ratios of carbon and nitrogen showed that the variation in OHC concentrations could not be explained by some walruses consuming higher trophic level diets, since all animals were found to feed at a similar trophic level. Antibodies against the bacteria Brucella spp. and the parasite Toxoplasma gondii were detected in 26% and 15% of the walruses, respectively. Given the absence of seal-predation, T. gondii exposure likely took place via the consumption of contaminated bivalves. The source of exposure to Brucella spp. in walruses is still unknown. Parapoxvirus DNA was detected in a single individual, representing the first documented evidence of parapoxvirus in wild walruses. Antibody prevalence was not related to contaminant exposure. Despite this, dynamic relationships between diet composition, contaminant bioaccumulation and pathogen exposure warrant continuing attention given the likelihood of climate change induced habitat and food web changes, and consequently OHC exposure, for Svalbard walruses in the coming decades.

Hundreds of Unrecognized Halogenated Contaminants Discovered in Polar Bear Serum

Exposure of polar bears (Ursus maritimus) to persistent organic pollutants was discovered in the 1970s, but recent evidence suggests the presence of unknown toxic chemicals in their blood. Protein and phospholipid depleted serum was stirred with polyethersulfone capillaries to extract a broad range of analytes, and nontarget mass spectrometry with "fragmentation flagging" was used for detection. Hundreds of analytes were discovered belonging to 13 classes, including novel polychlorinated biphenyl (PCB) metabolites and many fluorinated or chlorinated substances not previously detected. All analytes were detected in the oldest (mid-1980s) archived polar bear serum from Hudson Bay and Beaufort Sea, and all fluorinated classes showed increasing trends. A mouse experiment confirmed the novel PCB metabolites, suggesting that these could be widespread in mammals. Historical exposure and toxic risk has been underestimated, and these halogenated contaminants pose uncertain risks to this threatened species.

Are ingested plastics a vector of PCB contamination in northern fulmars from coastal Newfoundland and Labrador?

While marine animals are exposed to environmental contaminants via their prey, because plastic pollution in the aquatic environment can concentrate some chemicals, ingested plastics are thought to increase the exposure of biota to contaminants. Currently, in the literature there are contradictory results relating to how higher levels of ingested plastics by birds may lead to higher levels of polychlorinated biphenyl (PCBs). To date none of these have incorporated known Toxic Equivalency Factors (TEFs) for non-ortho and mono-ortho congeners of PCB which is critical to assessing the potential effects from PCBs. We examined northern fulmars (Fulmarus glacialis) from the Labrador Sea region Canada, and the ingested plastics from these same birds for comparative PCB concentrations. We found no significant correlations between the PCB concentrations in the birds and the mass or number of retained ingested plastic pieces in the stomach, this held true when PCBs were considered by a number of different ways, including ∑₄PCB, ∑PCB, lower-chlorinated, high-chlorinated, non-ortho PCB, and mono-ortho congeners. PCB concentrations were lower in plastics as compared with livers. We found significant differences in congener profiles between the ingested plastics and seabird livers suggesting that while plastics do not contribute to the PCB concentrations, there may be some interactions between plastics and the chemicals that the birds are exposed to via ingested plastics.

Organochlorines, perfluoroalkyl substances, mercury, and egg incubation temperature in an Arctic seabird: Insights from data loggers

In birds, incubation-related behaviors and brood patch formation are influenced by hormonal regulation such as prolactin secretion. Brood patch provides efficient heat transfer between the incubating parent and the developing embryo in the egg. Importantly, several environmental contaminants are already known to have adverse effects on avian reproduction. However, relatively little is known about the effect of contaminants on incubation temperature (T_inc ) in wild birds. By using temperature thermistors placed into artificial eggs, we investigated whether the most contaminated parent birds are less able to provide appropriate egg warming and thus less committed to incubating their clutch. Specifically, we investigated the relationships among 3 groups of contaminants (organochlorines, perfluoroalkyl substances [PFASs], and mercury [Hg]) with T_inc and also with prolactin concentrations and brood patch size in incubating Arctic black-legged kittiwakes (Rissa tridactyla). Our results reveal that among the organochlorines considered, only blood levels of oxychlordane, the main metabolite of chlordane, a banned pesticide, were negatively related to the minimum incubation temperature in male kittiwakes. Levels of PFASs and Hg were unrelated to T_inc in kittiwakes. Moreover, our study suggests a possible underlying mechanism: since we reported a significant and negative association between blood oxychlordane concentrations and the size of the brood patch in males. Finally, this reduced T_inc in the most oxychlordane-contaminated kittiwakes was associated with a lower egg hatching probability. Environ Toxicol Chem 2018;37:2881-2894. © 2018 SETAC.

Influence of persistent organic pollutants on the endocrine stress response in free-living and captive red kites (Milvus milvus)

Persistent organic pollutants (POPs) have the potential to impair the endocrine regulation of organisms and alter their ability to respond to environmental changes. We studied whether polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) affected the endocrine regulation of free-living and captive red kites (Milvus milvus) through studying the dynamics of corticosterone (CORT) and dehydroepiandrosterone (DHEA). We sampled migratory free-living kites coming from northern Europe and captive kites born in a rehabilitation center in Spain. We used body feathers from the interscapular region as a minimally-invasive and integrative matrix. The most abundant compound detected in free-living kites was 4,4'-dichlorodiphenyldichloroethylene (4,4'-DDE; 6.10 ± 1.56 ng g^-1 dw feather) followed by CB-153 (3.10 ± 0.63 ng g^-1 dw feather) and CB-180 (2.43 ± 1.08 ng g^-1 dw feather). In captive kites, the most abundant compounds were 4,4'-dichlorodyphenyltrichloroethane (4,4'-DDT; 2.38 ± 1.30 ng g^-1 dw feather), CB-153 (2.15 ± 0.47 ng g^-1 dw feather) and hexachlorobenzene (HCB; 2.03 ± 0.45 ng g^-1 dw feather) at similar concentrations. Free-living kites showed higher levels of 4,4'-DDE and CB-180 in comparison to captive kites. Age influenced HCB and CB-101 levels, whereas body mass was inversely related to CB-180 and 4,4'-DDT. Interestingly, captive kites showed a ratio DDT/DDE higher than 1 suggesting a relatively recent exposure of DDT, in contrast to free-living kites. Regarding hormonal levels, free-living kites showed higher levels of CORT (3.30 ± 0.22 pg mm^-1 feather) than captive (2.40 ± 0.16 pg mm^-1 feather), reflecting higher allostatic load. In addition, a positive association between PCBs and DDTs and adrenal hormones was found in free-living kites, suggesting an increase of CORT as a response of the endocrine system to cope with stressors and a subsequent elevation of DHEA to ameliorate the potential negative effects that high CORT levels could cause to the organism.

Unusually high Deca-BDE concentrations and new flame retardants in a Canadian Arctic top predator, the glaucous gull

Despite a sustained effort in surveying flame retardants (FRs) in wildlife from industrialized regions, their occurrence in birds or any other wildlife species spanning the Arctic regions, particularly in North America, has received limited attention. This study investigated in the top predator glaucous gull (Larus hyperboreus) breeding in the Eastern Canadian Arctic (Cape Dorset, Nunavut) a comprehensive suite of FRs including unstudied halogenated and non-halogenated FRs of potential health concern, along with legacy organochlorines and mercury. The influence of diet acquired locally and in wintering areas on the tissue contaminant profiles was also investigated using δ¹⁵N and δ¹³C signatures in liver and feathers. The principal constituent in the Deca-brominated diphenyl ether (BDE) mixture, BDE-209, was remarkably the most concentrated PBDE congener determined in liver samples of Eastern Canadian Arctic glaucous gulls. This suggests dietary exposure from the local marine food web and perhaps also from nearby community landfills. Moreover, this study revealed for the first time the presence of 16 emerging halogenated and non-halogenated FRs in glaucous gulls from this Arctic region including HBB, DDC-CO (anti and syn isomers), PBEB, EHTBB, BEHTBP as well as a series of organophosphate esters (OPEs) (TCEP, TCIPP, TPP, TDCIPP, TDBPP, TBNP, TBOEP, TBEP, TCrP, EHDPP, and TEHP). With the exception of BDE-209, concentrations of other halogenated FRs and organochlorines were found to be in the lower range in liver of Eastern Canadian Arctic glaucous gulls compared to individuals from other circumpolar populations (Svalbard and Greenland). Mercury and methylmercury concentrations, however, were greater than reported elsewhere for glaucous gull populations.

Analysis of a broad range of perfluoroalkyl acids in accipiter feathers: method optimization and their occurrence in Nam Co Basin, Tibetan Plateau

Perfluoroalkyl acids (PFAAs) are ubiquitous in the environment. They are prone to accumulate in organisms and have raised public attention in recent decades. Feather samples have been successfully applied as nondestructive indicators for several contaminants. However, a sophisticated analytical method for determining PFAAs in feathers is still lacking. In the present study, a series of conditions, such as the use of the solid-phase extraction cartridge type and extraction/digestion methods, were optimized for the analysis of 13 PFAAs in feathers. According to the spiked recoveries, a weak-anion exchange cartridge was chosen and the methanol was selected as the extraction solvent. In the present study, an optimized pretreatment procedure combined with high-performance liquid chromatography-electrospray ionization-tandem mass spectrometric (HPLC-ESI-MS/MS) method was established for the determination of PFAAs in feathers. The recoveries and method detection limits of the PFAAs ranged from 71 to 120% and 0.16 to 0.54 ng/g, respectively. Finally, 13 PFAAs in four accipiter feather samples from Nam Co Basin, Tibetan Plateau, were analyzed, indicating that PFOS was the predominant PFAA in accipiter feathers, with an average of 4.67 ng/g, followed by the short-chain PFAAs, PFBS and PFBA, with averages of 1.91 and 1.39 ng/g, respectively. These results partly indicated the current situation of PFAA pollution in the Nam Co Basin, especially the existence of short-chain PFAAs in this region.

Predicting global killer whale population collapse from PCB pollution

Killer whales (Orcinus orca) are among the most highly polychlorinated biphenyl (PCB)–contaminated mammals in the world, raising concern about the health consequences of current PCB exposures. Using an individual-based model framework and globally available data on PCB concentrations in killer whale tissues, we show that PCB-mediated effects on reproduction and immune function threaten the long-term viability of >50% of the world’s killer whale populations. PCB-mediated effects over the coming 100 years predicted that killer whale populations near industrialized regions, and those feeding at high trophic levels regardless of location, are at high risk of population collapse. Despite a near-global ban of PCBs more than 30 years ago, the world’s killer whales illustrate the troubling persistence of this chemical class.

PAH and PCB contamination in the sediments of the Venice Lagoon (Italy) before the installation of the MOSE flood defence works

Contamination from polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the shallow water areas of the Venice Lagoon (415 km²) was investigated in the surface (0-5 cm) and sub-surface (5-10 cm) sediments by collecting cores from 380 sites. The concentrations of 14 PAHs (USEPA priority pollutants) and seven PCB indicator congeners were analysed with high-performance liquid chromatography (HPLC) and capillary gas chromatography (GC), respectively. PAH and PCB concentrations ranged from 2.75 to 9980 ng g^-1 d.w. and from 0.01 to 60.1 ng g^-1 d.w., respectively. Their concentrations never exceeded the probable effect level (PEL) stipulated in the respective quality guidelines. In addition, the average total PAH levels expressed as B[a]P toxicity equivalents (total TEQ) were lower in the sediments of the Venice Lagoon than in other literature-reported zones in the Mediterranean. PAH profiles and ratios showed that they originated not only largely from high-temperature pyrolytic processes attributable primarily to the burning of fossil fuels but also partly from petroleum spillage. Comparison of tetra-to-hepta PCB congeners enabled the PCB profiles observed in the lagoon environment to be characterised as Aroclor 1254 and 1260 (1:1). Compared to other marine coastal areas and harbours in the Mediterranean, the Venice Lagoon sediments showed a low mean value but a wide range of concentrations. The estimation of PAH and PCB inventories indicated the low contribution of atmospheric deposition relative to local sources.

Immunologic, reproductive, and carcinogenic risk assessment from POP exposure in East Greenland polar bears (Ursus maritimus) during 1983-2013

Polar bears (Ursus maritimus) are among the world's highest trophic level marine predators and as such have some of the highest tissue concentrations of organohalogen contaminants (OHCs) among Arctic biota. In this paper we present the results of a three decade (1983-2013) risk assessment of OHC exposure and effects on reproduction, immunity, and cancer (genotoxicity) in polar bears from Central East Greenland. Risk of adverse effects are evaluated using a risk quotient (RQ) approach with derivation from measured OHC concentrations in polar bear tissue and critical body residues (CBR) extrapolated for polar bears using physiologically-based pharmacokinetic modelling (PBPK). The additive RQs for all OHCs in polar bears were above the threshold for all effect categories (RQ > 1) in every year, suggesting this population has been at significant and continuous risk of contaminant-mediated effects for over three decades. RQs peaked in 1983 (RQ > 58) and again in 2013 (RQ > 50) after a period of decline. These trends follow ΣPCB levels during that time, and contributed almost all of the risk to immune, reproductive, and carcinogenic effects (71-99% of total RQ). The recent spike in RQs suggests a major shift in polar bear contaminant exposure from climate related changes in food composition and hereby the increased risk of adverse health effects. In the context of lifetime exposure ΣPCB and PFOS levels showed the interactive importance of year of birth, age, and emission history. In conclusion, the results indicate that East Greenland polar bears have been exposed to OHC levels over the period of 1983-2013 that potentially and continuously affected individual and theoretically also population health, with a peaking risk in the more recent years.

The association between reproductive success with persistent organochlorine pollutants residue in feathers of spur-winged lapwing (Vanellus spinosus L.)

The reproductive and breeding success of wader species is negatively affected by various anthropogenic factors, including persistent organochlorine pollutants (POPs). We aimed to study the association of POPs in feathers with the reproductive success of the spur-winged lapwing (Vanellus spinosus). For this purpose, data on reproductive parameters and feather samples were collected from a breeding population consisting of 19 pairs near Boğazkent district in Antalya, Turkey. Mean concentrations of total polychlorinated biphenyls (ΣPCBs) and organochlorine pesticides (ΣOCPs) were found to be 54 ± 16 ng/g and 520 ng/g in all samples, respectively. In particular, PCB 151 and β-hexachlorocyclohexane had a negative association the various reproductive parameters in the species under consideration. Fledgling success (n = 25) was calculated to be 37.4%, which was negatively associated with the ΣOCP concentrations (r = - 0.99, p = 0.01). According to the results, POP residues are one of the associated factors on the reproductive success of spur-winged lapwing along, with agricultural activity and predation. It is indicated that the species needs a protection plan for prevention declining reproductive success and population size species in Turkey. Besides, our results suggest that bird feathers are a non-destructive bio-monitoring tools to estimate of contamination levels of organic pollutants in a population.

Development of chicken and fish muscle protein - Water partition coefficients predictive models for ionogenic and neutral organic chemicals

Muscle protein was one of critical accumulation protein for anthropogenic chemicals. However, few predictive models were constructed for muscle protein up to now. In addition, some ionizable chemicals classes e.g. sulfonates were not successfully modeled in previously models, indicating considerable work would be needed. The major objective of this study was to develop quantitative structure-activity relationship (QSAR) models for predicting the muscle protein-water partition coefficient (logK_MP/w) of chicken and fish. In the modeling, the n-octanol/water distribution coefficient (logD), functional groups, atom-centred fragments and chemical form adjusted descriptors were used to construct the models. The application domain of the derived models was defined by the Euclidean distance-based method and Williams plot. The modeling results indicated that the determination coefficient (R²), leave-one out cross validation Q² (Q²_LOO) and bootstrapping coefficient (Q²_BOOT) of the QSAR models for chicken and fish were 0.882 and 0.929, 0.844 and 0.906, 0.779 and 0.792, respectively, implying the models had good goodness-of-fit and robustness. The coefficient determination (R²_EXT) and external validation coefficient (Q²_EXT) of the validation set for the two models were 0.874 and 0.937, 0.869 and 0.915, respectively, indicating the models had good predictive ability. The predictor variables selected to construct the logK_MP/w models of chicken and fish included logD, the function groups, and the fraction of the ionized species (δ_I). Considering the molecular descriptors used here can be calculated from their molecular structures directly, the developed models could be easily used to fill the logK_MP/w data gap for other chemicals within the applicability domain.

Polychlorinated biphenyls (PCBs) as sentinels for the elucidation of Arctic environmental change processes: a comprehensive review combined with ArcRisk project results

Polychlorinated biphenyls (PCBs) can be used as chemical sentinels for the assessment of anthropogenic influences on Arctic environmental change. We present an overview of studies on PCBs in the Arctic and combine these with the findings from ArcRisk-a major European Union-funded project aimed at examining the effects of climate change on the transport of contaminants to and their behaviour of in the Arctic-to provide a case study on the behaviour and impact of PCBs over time in the Arctic. PCBs in the Arctic have shown declining trends in the environment over the last few decades. Atmospheric long-range transport from secondary and primary sources is the major input of PCBs to the Arctic region. Modelling of the atmospheric PCB composition and behaviour showed some increases in environmental concentrations in a warmer Arctic, but the general decline in PCB levels is still the most prominent feature. 'Within-Arctic' processing of PCBs will be affected by climate change-related processes such as changing wet deposition. These in turn will influence biological exposure and uptake of PCBs. The pan-Arctic rivers draining large Arctic/sub-Arctic catchments provide a significant source of PCBs to the Arctic Ocean, although changes in hydrology/sediment transport combined with a changing marine environment remain areas of uncertainty with regard to PCB fate. Indirect effects of climate change on human exposure, such as a changing diet will influence and possibly reduce PCB exposure for indigenous peoples. Body burdens of PCBs have declined since the 1980s and are predicted to decline further.

Effects of biometrics, location and persistent organic pollutants on blood clinical-chemical parameters in polar bears (Ursus maritimus) from Svalbard, Norway

In the present study, blood clinical-chemical parameters (BCCPs) were analysed in 20 female and 18 male Svalbard polar bears (Ursus maritimus) captured in spring 2007. The aim was to study how age, body condition (BC), biometrics, plasma lipid content and geographical location may confound the relationship between persistent organic pollutants (POPs) including PCBs, HCB, chlordanes, DDTs, HCHs, mirex and OH-PCBs and the concentrations of 12 specific BCCPs (hematocrit [HCT], hemoglobin [HB], aspartate aminotransferase [ASAT], alanine aminotransferase [ALAT], γ-glutamyltransferase [GGT], creatine kinase [CK], triglycerides [TG], cholesterol [CHOL], high-density lipoprotein [HDL], creatinine (CREA], urea, potassium (K]), and to investigate if any of these BCCPs may be applied as potential biomarkers for POP exposure in polar bears. Initial PCA and O-PLS modelling showed that age, lipids, BC and geographical location (longitude and latitude) were important parameters explaining BCCPs in females. Following subsequent partial correlation analyses correcting for age and lipids, multiple POPs in females were still significantly correlated with HCT and HDL (all p < 0.05). In males, age, BM, BC and longitude were important parameters explaining BCCPs. Following partial correlation analyses correcting for age, biometrics, lipids and longitude in males, multiple POPs were significantly correlated with HCT, ASAT, GGT and CHOL (all p < 0.05). In conclusion, several confounding parameters has to be taken into account when studying the relations between BCCPs and POPs in polar bears. When correcting for these, in particular HCT may be used as a simple cost-efficient biomarker of POP exposure in polar bears. Furthermore, decreasing HDL concentrations and increasing CHOL concentration with increasing POP concentrations may indicate responses related to increased risk of cardiovascular disease. We therefore suggest to further study POP exposure and lipidome response to increase knowledge of the risk of cardiometabolic syndrome in polar bears.

An endocrine-disrupting agricultural contaminant impacts sequential female mate choice in fish

The environmental impact of endocrine-disrupting chemicals (EDCs)-compounds that interfere with endocrine system function at minute concentrations-is now well established. In recent years, concern has been mounting over a group of endocrine disruptors known as hormonal growth promotants (HGPs), which are natural and synthetic chemicals used to promote growth in livestock by targeting the endocrine system. One of the most potent compounds to enter the environment as a result of HGP use is 17β-trenbolone, which has repeatedly been detected in aquatic habitats. Although recent research has revealed that 17β-trenbolone can interfere with mechanisms of sexual selection, its potential to impact sequential female mate choice remains unknown, as is true for all EDCs. To address this, we exposed female guppies (Poecilia reticulata) to 17β-trenbolone at an environmentally relevant level (average measured concentration: 2 ng/L) for 21 days using a flow-through system. We then compared the response of unexposed and exposed females to sequentially presented stimulus (i.e., unexposed) males that varied in their relative body area of orange pigmentation, as female guppies have a known preference for orange colouration in males. We found that, regardless of male orange pigmentation, both unexposed and exposed females associated with males indiscriminately during their first male encounter. However, during the second male presentation, unexposed females significantly reduced the amount of time they spent associating with low-orange males if they had previously encountered a high-orange male. Conversely, 17β-trenbolone-exposed females associated with males indiscriminately (i.e., regardless of orange colouration) during both their first and second male encounter, and, overall, associated with males significantly less than did unexposed females during both presentations. This is the first study to demonstrate altered sequential female mate choice resulting from exposure to an endocrine disruptor, highlighting the need for a greater understanding of how EDCs may impact complex mechanisms of sexual selection.

Effects of Low-level Brodifacoum Exposure on the Feline Immune Response

Anticoagulant rodenticides have been implicated as a potential inciting factor in the development of mange in wild felids, but a causative association between anticoagulant rodenticide exposure and immune suppression has not been established. Specific-pathogen-free domestic cats were exposed to brodifacoum over a 6-week period to determine whether chronic, low-level exposure altered the feline immune response. Cats were vaccinated with irrelevant antigens at different points during the course of the experiment to assess recall and direct immune responses. Measures of immune response included delayed-type hypersensitivity tests and cell proliferation assays. IgE and antigen-specific antibodies were quantified via ELISA assays, and cytokine induction following exposure to vaccine antigens was also analyzed. While cats had marked levels of brodifacoum present in blood during the study, no cats developed coagulopathies or hematologic abnormalities. Brodifacoum-exposed cats had transient, statistically significant decreases in the production of certain cytokines, but all other measures of immune function remained unaffected throughout the study period. This study indicates that cats may be more resistant to clinical effects of brodifacoum exposure than other species and suggests that the gross impacts of environmentally realistic brodifacoum exposure on humoral and cell-mediated immunity against foreign antigen exposures in domestic cats are minimal.

Electrochemical enzymatic fenitrothion sensor based on a tyrosinase/poly(2-hydroxybenzamide)-modified graphite electrode

This paper reports the electrosynthesis and characterisation of a polymeric film derived from 2-hydroxybenzamide over a graphite electrode and its application as an enzymatic biosensor for the determination and quantification of the pesticide fenitrothion. The material was analysed by scanning electron microscopy and its electrochemical properties characterised by cyclic voltammetry and electrochemical impedance spectroscopy. The enzyme tyrosinase was immobilised over the modified electrode by the drop and dry technique. Catechol was determined by direct reduction of biocatalytically formed o-quinone by employing the flow injection analysis technique. The analytical characteristics of the proposed sensor were optimised as follows: phosphate buffer 0.050 M at pH 6.5, flow rate 5.0 mL min^-1, sample injection volume 150 μL, catechol concentration 1.0 mM and maximum inhibition time by fenitrothion of 6 min. The biosensors showed a linear response to pesticide concentration from 0.018 to 3.60 μM. The limit of detection and limit of quantification were calculated as 4.70 nM and 15.9 nM (RSD < 2.7%), respectively. The intra- and inter-electrode RSDs were 3.35% (n = 15) and 8.70% (n = 7), respectively. In addition, water samples spiked with the pesticide showed an average recovery of 97.6% (±1.53).

Blood concentrations of p,p'-DDE and PCBs in harriers breeding in Spain and Kazakhstan

Organochlorine compounds (OC) are of interest in current biomonitoring studies because of their well-known persistence, accumulation capacity and the adverse effects they caused in the past. P,p'-DDE has been shown to cause severe reproductive failures and population declines in birds of prey. However, there are knowledge gaps regarding OC exposure for some species (e.g. harriers), the historical record and the broader picture. The main goal was to evaluate exposure to p,p'-DDE and PCBs in two raptor species: Montagu's and pallid harriers (Circus pygargus and Circus macrourus), and to investigate if birds from different breeding areas and wintering grounds differ in pollutant levels. For this purpose, we collected blood of adult and nestling Montagu's and pallid harriers breeding in the natural steppes of Kazakhstan, and adult and nestling Montagu's harriers breeding in agricultural and natural habitats of Spain, in 2007-2008. We determined the blood concentrations of p,p'-DDE and PCBs. Adult harriers generally showed higher concentrations of p,p'-DDE and PCBs than nestlings, probably because they had more time for a progressive accumulation of these compounds due to a higher intake than excretion rate. The p,p'-DDE concentrations in adults were equivalent in all the studied areas. The ratio p,p'-DDE/PCB 153 was higher in adults than in nestlings, suggesting that a portion of the p,p'-DDE in adult harriers may have come from p,p'-DDT applied in the past in the wintering areas. Overall, the concentrations of p,p'-DDE and ∑PCBs reported were generally low and below any demonstrated threshold of harm.

Organohalogens Naturally Biosynthesized in Marine Environments and Produced as Disinfection Byproducts Alter Sarco/Endoplasmic Reticulum Ca2+ Dynamics

Contemporary sources of organohalogens produced as disinfection byproducts (DBPs) are receiving considerable attention as emerging pollutants because of their abundance, persistence, and potential to structurally mimic natural organohalogens produced by bacteria that serve signaling or toxicological functions in marine environments. Here, we tested 34 organohalogens from anthropogenic and marine sources to identify compounds active toward ryanodine receptor (RyR1), known toxicological targets of non-dioxin-like polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). [3H]Ryanodine ([3H]Ry) binding screening (≤2 μM) identified 10 highly active organohalogens. Further analysis indicated that 2,3-dibromoindole (14), tetrabromopyrrole (31), and 2,3,5-tribromopyrrole (34) at 10 μM were the most efficacious at enhancing [3H]Ry binding. Interestingly, these congeners also inhibited microsomal sarcoplasmic/endoplasmic reticulum (SR/ER) Ca2+ ATPase (SERCA1a). Dual SERCA1a inhibition and RyR1 activation triggered Ca2+ efflux from microsomal vesicles with initial rates rank ordered 31 > 34 > 14. Hexabromobipyrroles (25) enhanced [3H]Ry binding moderately with strong SERCA1a inhibition, whereas pyrrole (24), 2,3,4-tribromopyrrole (26), and ethyl-4-bromopyrrole-2-carboxylate (27) were inactive. Of three PBDE derivatives of marine origin active in the [3H]Ry assay, 4'-hydroxy-2,3',4,5',6-pentabromodiphenyl ether (18) was also a highly potent SERCA1a inhibitor. Molecular targets of marine organohalogens that are also DBPs of emerging environmental concern are likely to contribute to their toxicity.

Exposure to perfluoroalkyl substances during pregnancy and child behaviour at 5 to 9years of age

We examined associations between prenatal exposure to perfluorohexane sulfonic acid (PFHxS), perfluoroheptanoic acid (PFHpA), perfluorononanoic acid (PFNA), and perfluorodecanic acid (PFDA) - and child behaviour (SDQ-total) and hyperactivity (sub-scale) at 5-9years of age in birth cohorts from Greenland and Ukraine. Pregnancy serum samples (N=1023) were analysed for perfluoroalkyl substances (PFASs) and categorised into tertiles and also used as continuous exposure variables. Problem behaviour and hyperactivity were assessed, using the Strength and Difficulties Questionnaire (SDQ) and categorised as normal/borderline and abnormal. Associations were analysed using multiple logistic and linear regression. High compared to low prenatal PFHxS exposure was associated with 1.16 (95% confidence interval (CI): 0.08; 2.25) point higher SDQ-total (more problem behaviour) in Greenland and 0.80 (CI: 0.06; 1.54) point higher SDQ-total in the combined analyses, whereas no association was present in Ukraine alone. One natural log-unit increase in prenatal PFNA exposure was associated with 0.90 (CI: 0.10; 1.71) points higher SDQ-total in Greenland and 0.72 (CI: 0.13; 1.31) points higher in the combined analysis and no association in Ukraine. Prenatal PFAS exposure was unrelated to problem behaviour (abnormal SDQ-total). In the combined analysis, odds ratio (OR) (CI) for hyperactivity was 1.8 (1.0; 3.2) for one natural log-unit increase in prenatal PFNA and 1.7 (1.0; 3.1) for one natural log-unit increase in prenatal PFDA exposure. Findings are compatible with weak effects on child behaviour of prenatal exposure to some PFASs although spurious results are not entirely unlikely. The associations were strongest in Greenland.

Persistent organic pollutants and penile bone mineral density in East Greenland and Canadian polar bears (Ursus maritimus) during 1996-2015

Persistent organic pollutants (POPs) are long-range transported to the Arctic via atmospheric and oceanic currents, where they biomagnify to high concentrations in the tissues of apex predators such as polar bears (Ursus maritimus). A major concern of POP exposure is their physiological effects on vital organ-tissues posing a threat to the health and survival of polar bears. Here we examined the relationship between selected POPs and baculum bone mineral density (BMD) in the East Greenland and seven Canadian subpopulations of polar bears. BMD was examined in 471 bacula collected between years 1996-2015 while POP concentrations in adipose tissue were determined in 67-192 of these individuals collected from 1999 to -2015. A geographical comparison showed that baculum BMD was significantly lowest in polar bears from East Greenland (EG) when compared to Gulf of Boothia (GB), Southern Hudson (SH) and Western Hudson (WH) Bay subpopulations (all p < 0.05). The calculation of a T-score osteoporosis index for the EG subpopulation using WH bears as a reference group gave a T-score of -1.44 which indicate risk of osteopenia. Concentrations of ΣPCB₇₄ (polychlorinated biphenyls), ΣDDT₃ (dichlorodiphenyltrichloroethanes), p,p'-DDE (dichlorodiphenyldichloroethylene), ΣHCH₃ (hexachlorohexane) and α-HCH was significantly highest in EG bears while ΣPBDE (polybrominated diphenyl ethers), BDE-47 and BDE-153 was significantly highest in SH bears (all p < 0.04). Statistical analyses of individual baculum BMD vs. POP concentrations showed that BMD was positively correlated with ΣPCB₇₄, CB-153, HCB (hexachlorobenzene), ΣHCH, β-HCH, ClBz (chlorobenzene), ΣPBDE and BDE-153 (all p < 0.03). In conclusion, baculum density was significantly lowest in East Greenland polar bears despite the positive statistical correlations of BMD vs. POPs. Other important factors such as nutritional status, body mass and body condition was not available for the statistical modelling. Since on-going environmental changes are known to affect these, future studies need to incorporate nutritional, endocrine and genetic parameters to further understand how POP exposure may disrupt bone homeostasis and affect baculum BMD across polar bear subpopulations.

Interactions of climate, socio-economics, and global mercury pollution in the North Water

Despite the remoteness of the North Water, Northwest Greenland, the local Inughuit population is affected by global anthropogenic pollution and climate change. Using a cross-disciplinary approach combining Mercury (Hg) analysis, catch information, and historical and anthropological perspectives, this article elucidates how the traditional diet is compromised by Hg pollution originating from lower latitudes. In a new approach we here show how the Inughuits in Avanersuaq are subject to high Hg exposure from the hunted traditional food, consisting of mainly marine seabirds and mammals. Violation of the provisional tolerably yearly intake of Hg, on average by a factor of 11 (range 7-15) over the last 20 years as well as the provisional tolerably monthly intake by a factor of 6 (range 2-16), raises health concerns. The surplus of Selenium (Se) in wildlife tissues including narwhals showed Se:Hg molar ratios of 1.5, 2.3, and 16.7 in muscle, liver, and mattak, respectively, likely to provide some protection against the high Hg exposure.

Persistent organic pollutants, skull size and bone density of polar bears (Ursus maritimus) from East Greenland 1892-2015 and Svalbard 1964-2004

We investigated skull size (condylobasal length; CBL) and bone mineral density (BMD) in polar bears (Ursus maritimus) from East Greenland (n = 307) and Svalbard (n = 173) sampled during the period 1892-2015 in East Greenland and 1964-2004 at Svalbard. Adult males from East Greenland showed a continuous decrease in BMD from 1892 to 2015 (linear regression: p < 0.01) indicating that adult male skulls collected in the early pre-pollution period had the highest BMD. A similar decrease in BMD over time was not found for the East Greenland adult females. However, there was a non-significant trend that the skull size of adult East Greenland females was negatively correlated with collection year 1892-2015 (linear regression: p = 0.06). No temporal change was found for BMD or skull size in Svalbard polar bears (ANOVA: all p > 0.05) nor was there any significant difference in BMD between Svalbard and East Greenland subpopulations. Skull size was larger in polar bears from Svalbard than from East Greenland (two-way ANOVA: p = 0.003). T-scores reflecting risk of osteoporosis showed that adult males from both East Greenland and Svalbard are at risk of developing osteopenia. Finally, when correcting for age and sex, BMD in East Greenland polar bears increased with increasing concentrations of persistent organic pollutants (POPs) i.e. ΣPCB (polychlorinated biphenyls), ΣHCH (hexachlorohexane), HCB (hexachlorobenzene) and ΣPBDE (polybrominated diphenyl ethers) while skull size increased with ΣHCH concentrations all in the period 1999-2014 (multiple linear regression: all p < 0.05, n = 175). The results suggest that environmental changes over time, including exposure to POPs, may affect bone density and size of polar bears.

DNA damage in Arctic seabirds: Baseline, sensitivity to a genotoxic stressor, and association with organohalogen contaminants

Environmental contaminants are found throughout Arctic marine ecosystems, and their presence in seabirds has been associated with toxicological responses. However, there are few studies of genotoxicity in Arctic avian wildlife. The purpose of the present study was to quantify deoxyribonucleic acid (DNA) damage in lymphocytes of selected seabird species and to examine whether accumulation of organohalogen contaminants (ΣOHCs) affects DNA damage. Blood was sampled from common eider (Somateria mollissima), black guillemot (Cepphus grylle), black-legged kittiwake (Rissa tridactyla), glaucous gull (Larus hyperboreus), arctic skua (Stercorarius parasiticus), and great skua (Stercorarius skua) in Kongsfjorden, Svalbard (Norway). Contaminant concentrations found in the 6 species differed, presumably because of foraging ecology and biomagnification. Despite large differences in contaminant concentrations, ranging from ΣOHCs 3.3 ng/g wet weight in the common eider to ΣOHCs 895 ng/g wet weight in the great skua, there was no strong difference among the species in baseline DNA damage or sensitivity to a genotoxic stressor (hydrogen peroxide). Baseline levels of DNA damage were low, with median values ranging from 1.7% in the common eider to 8.6% in the great skua. There were no associations between DNA damage and contaminants in the investigated species, suggesting that contaminant concentrations in Kongsfjorden are too low to evoke genotoxic effects, or possibly that lymphocytes are resistant to strand breakage. Clearly, genotoxicity is a topic for future studies of Arctic seabirds. Environ Toxicol Chem 2018;37:1084-1091. © 2017 SETAC.

Organophosphate esters in East Greenland polar bears and ringed seals: Adipose tissue concentrations and in vitro depletion and metabolite formation

East Greenland is a contamination "hot spot" for long-range transported anthropogenic chemicals, including organophosphate esters (OPEs). High concentrations of OPEs have been reported in arctic air while very little is known for wildlife where OPE tissue residues levels appear to be strongly influenced by biotransformation. In the present study, the hepatic in vitro metabolism of six environmentally relevant organophosphate (OP) triesters and corresponding OP diester formation were investigated in East Greenland polar bears (PBs) and ringed seals (RSs). The in vitro metabolism assay results were compared to adipose levels in field samples from the same individuals. In vitro OP triester metabolism was generally rapid and structure-dependent, where PBs metabolized OPEs more rapidly than RSs. Exceptions were the lack of triethyl phosphate (TEP) metabolism and slow metabolism of tris(2-ethylhexyl) phosphate (TEHP) in both species. OP diester metabolites were also formed with the exception of TEP which was not metabolized at all. Tris(1,3-dichloro-2-propyl) phosphate was completely converted to its corresponding diester. However, the mass balances showed that OP diester formation corresponding to TEHP, tri(n-butyl) phosphate, and tris(2-butyoxyethyl) phosphate did not account for 100% of the OP triester depletion, which indicated alternate pathways of OP triester metabolism had occurred. Triphenyl phosphate was completely converted to its OP diester metabolite in PBs but not in RSs suggesting species-specific differences. The results demonstrated that OP triester bioaccumulation and fate in PBs versus their RS prey is substantially influenced by biotransformation.

The distribution and trends of persistent organic pollutants and mercury in marine mammals from Canada's Eastern Arctic

Arctic contaminant research in the marine environment has focused on organohalogen compounds and mercury mainly because they are bioaccumulative, persistent and toxic. This review summarizes and discusses the patterns and trends of persistent organic pollutants (POPs) and mercury in ringed seals (Pusa hispida) and polar bears (Ursus maritimus) in the Eastern Canadian Arctic relative to the rest of the Canadian Arctic. The review provides explanations for these trends and looks at the implications of climate-related changes on contaminants in these marine mammals in a region that has been reviewed little. Presently, the highest levels of total mercury (THg) and the legacy pesticide HCH in ringed seals and polar bears are found in the Western Canadian Arctic relative to other locations. Whereas, highest levels of some legacy contaminants, including ∑PCBs, PCB 153, ∑DDTs, p,p'-DDE, ∑CHLs, ClBz are found in the east (i.e., Ungava Bay and Labrador) and in the Beaufort Sea relative to other locations. The highest levels of recent contaminants, including PBDEs and PFOS are found at lower latitudes. Feeding ecology (e.g., feeding at a higher trophic position) is shaping the elevated levels of THg and some legacy contaminants in the west compared to the east. Spatial and temporal trends for POPs and THg are underpinned by historical loadings of surface ocean reservoirs including the Western Arctic Ocean and the North Atlantic Ocean. Trends set up by the distribution of water masses across the Canadian Arctic Archipelago are then acted upon locally by on-going atmospheric deposition, which is the dominant contributor for more recent contaminants. Warming and continued decline in sea ice are likely to result in further shifts in food web structure, which are likely to increase contaminant burdens in marine mammals. Monitoring of seawater and a range of trophic levels would provide a better basis to inform communities about contaminants in traditionally harvested foods, allow us to understand the causes of contaminant trends in marine ecosystems, and to track environmental response to source controls instituted under international conventions.

Choose Your Poison-Space-Use Strategy Influences Pollutant Exposure in Barents Sea Polar Bears

Variation in space-use is common within mammal populations. In polar bears, Ursus maritimus, some individuals follow the sea ice (offshore bears) whereas others remain nearshore yearlong (coastal bears). We studied pollutant exposure in relation to space-use patterns (offshore vs coastal) in adult female polar bears from the Barents Sea equipped with satellite collars (2000-2014, n = 152). First, we examined the differences in home range (HR) size and position, body condition, and diet proxies (nitrogen and carbon stable isotopes, n = 116) between offshore and coastal space-use. Second, we investigated how HR, space-use, body condition, and diet were related to plasma concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) ( n = 113), perfluoroalkyl substances (PFASs; n = 92), and hydroxylated-PCBs ( n = 109). Offshore females were in better condition and had a more specialized diet than did coastal females. PCBs, OCPs, and hydroxylated-PCB concentrations were not related to space-use strategy, yet PCB concentrations increased with increasing latitude, and hydroxylated-PCB concentrations were positively related to HR size. PFAS concentrations were 30-35% higher in offshore bears compared to coastal bears and also increased eastward. On the basis of the results we conclude that space-use of Barents Sea female polar bears influences their pollutant exposure, in particular plasma concentrations of PFAS.

Hepatic phase I and II biotransformation responses and contaminant exposure in long-finned pilot whales from the Northeastern Atlantic

Faroe Island pilot whales have been documented to have high body burdens of organohalogen contaminants (OHCs), including polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), but low burdens of their respective hydroxylated metabolites (OH-PCBs and OH-PBDEs). The present study investigated the hepatic expression and/or catalytic activities of phase I and II biotransformation enzymes in relation to hepatic concentrations of target OHCs, including OH-PCBs and OH-PBDEs, in long-finned pilot whales (Globicephala melas) from the Northeastern Atlantic. CYP1A, 2B, 2E and 3A protein expressions were identified in juveniles and adult males, but not in adult females. Ethoxyresorufin-O-deethylase (EROD) activity was significantly lower in adult females than in juveniles and adult males. Using multivariate analyses to investigate relationships between biological responses and OHC concentrations, a positive relationship was identified between EROD and OHCs. The activity levels of phase II conjugating enzymes (uridine 5'-diphospho-glucuronosyltransferase [UDPGT], and glutathione S-transferase [GST]) were low. The analyses of mRNA expression did not show correlative relationships with OHC concentrations, but cyp1a and ahr transcripts were positively correlated with EROD activity. We suggest that the low concentrations of OH-PCBs and OH-PBDEs reported in pilot whales is probably due to the identified low phase I biotransformation activities in the species.

Endocrine disruption and differential gene expression in sentinel fish on St. Lawrence Island, Alaska: Health implications for indigenous residents

People living a subsistence lifestyle in the Arctic are highly exposed to persistent organic pollutants, including polychlorinated biphenyls (PCBs). Formerly Used Defense (FUD) sites are point sources of PCB pollution; the Arctic contains thousands of FUD sites, many co-located with indigenous villages. We investigated PCB profiles and biological effects in freshwater fish (Alaska blackfish [Dallia pectoralis] and ninespine stickleback [Pungitius pungitius]) living upstream and downstream of the Northeast Cape FUD site on St. Lawrence Island in the Bering Sea. Despite extensive site remediation, fish remained contaminated with PCBs. Vitellogenin concentrations in males indicated exposure to estrogenic contaminants, and some fish were hypothyroid. Downstream fish showed altered DNA methylation in gonads and altered gene expression related to DNA replication, response to DNA damage, and cell signaling. This study demonstrates that, even after site remediation, contaminants from Cold War FUD sites in remote regions of the Arctic remain a potential health threat to local residents - in this case, Yupik people who had no influence over site selection and use by the United States military.

Lifelong Exposure to PCBs in the Remote Norwegian Arctic Disrupts the Plasma Stress Metabolome in Arctic Charr

Lake Ellasjøen on the remote Norwegian island of Bjørnøya is populated by Arctic charr (Salvelinus alpinus) having 20-fold higher body burdens of polychlorinated biphenyls (PCB) compared to charr from the neighboring Lake Laksvatn. This provides a natural setting to test the hypothesis that lifelong exposure to PCBs compromises the energy metabolism in this northernmost living salmonid. To test this, blood was sampled from charr from both lakes immediately after capture and following a 1 h handling and confinement stressor to assess possible differences in their energy metabolism and energy substrate mobilization, respectively. The plasma metabolome of charr was assessed by metabolite detection/separation with LC-MS. Plasma metabolite profiles revealed differences in key pathways involved in amino acid metabolism between charr from each lake, underscoring an impact of PCBs on energy metabolism in Arctic charr residing in Lake Ellasjøen. Subjecting charr from either lake to an acute stressor altered the plasma metabolite profiles and revealed distinct stress metabolome in Lake Ellasjøen charr, suggesting a reduced metabolic capacity. Taken together, lifelong exposure to PCBs in Ellasjøen charr disrupts the plasma metabolome, and may impair the adaptive metabolic response to stressors, leading to a reduced fitness.

Legacy and new halogenated persistent organic pollutants in polar bears from a contamination hotspot in the Arctic, Hudson Bay Canada

A large and complex suite of 295 legacy and new halogenated persistent organic pollutants (POPs) were investigated in fat or liver tissue samples of polar bears collected in 2013-2014 from Southern (SHB) and Western (WHB) subpopulations of the Canadian Arctic contaminants hotspot of Hudson Bay. A total of 210 POPs were detected and/or quantifiable with some frequency in all fat or liver samples. POP profile and concentration differences were investigated both within (e.g. age and sex) and between the two subpopulations. Two time-point comparisons were made relative to POPs reported for Hudson Bay polar bears harvested in 2007-2008. ΣPolychlorinated biphenyl (PCB) concentrations at both time points were the most concentrated of the POP groups, and were spatially uniform with no detectable influence of sex or age, as were concentrations of the dominant congener CB153. ΣChlordanes (ΣCHLs, 74-79% oxychlordane) and the Σperfluoroalkyl substances (ΣPFASs, ≈60% perfluorooctane sulfonate (PFOS)) had the second greatest POP group concentrations in SHB and WHB respectively, with ΣPFASs and ΣCHLs being significantly influenced by age and/or sex. ΣCHLs were spatially uniform but ΣPFASs were greater in the SHB bears, as were e.g. some flame retardants, due to e.g. local contamination and/or changes in bear behavior and diet. Endosulfans and hexabromocyclododecane were detectable in samples from 2007-2008 but not from 2013-2014, which is consistent with their global POP regulations. ΣPolychlorinated naphthalenes (ΣPCNs) were consistently detected at relatively high concentrations compared to other arctic wildlife, however these concentrations were low relative to legacy POPs. ΣShort-chain chlorinated paraffins (ΣSCCPs) were major contributors to the overall POPs burden with concentrations comparable to other legacy POPs, though there was no significant difference between or within subpopulations for PCNs or SCCPs. Except for octachlorostyrene, POPs concentrations were generally lower in female and male bears from SHB in 2013-2014 relative to 2007-2008, however those of WHB males were greater over the same timeframe for almost all POPs.

Introduction: A Brief Guide to the Periconception Environment

Definition of the periconception period is not an exact science and is probably somewhat arbitrary. One can define it as spanning the period from the final stages of gamete maturation until formation of the embryo and the stages of embryonic development and implantation. Hence, the periconception period includes periods when spermatozoa are in the female reproductive tract, oocytes are matured and ovulated into the oviduct, fertilization occurs and the embryo undergoes development. By definition the implantation process and the early stages of placenta formation are also regarded as a part of the periconception period. In this article we highlight a few of the major advances which have transformed this topic over the last two decades. It is now clear that the fitness and wellbeing of developing mammalian embryos, including the human, are highly dependent on the health status, diet and habits of both parents especially in the months and weeks that precede the formation of oocytes and spermatozoa.

A veterinary perspective on One Health in the Arctic

Exposure to long-range transported industrial chemicals, climate change and diseases is posing a risk to the overall health and populations of Arctic wildlife. Since local communities are relying on the same marine food web as marine mammals in the Arctic, it requires a One Health approach to understand the holistic ecosystem health including that of humans. Here we collect and identify gaps in the current knowledge of health in the Arctic and present the veterinary perspective of One Health and ecosystem dynamics. The review shows that exposure to persistent organic pollutants (POPs) is having multiple organ-system effects across taxa, including impacts on neuroendocrine disruption, immune suppression and decreased bone density among others. Furthermore, the warming Arctic climate is suspected to influence abiotic and biotic long-range transport and exposure pathways of contaminants to the Arctic resulting in increases in POP exposure of both wildlife and human populations. Exposure to vector-borne diseases and zoonoses may increase as well through range expansion and introduction of invasive species. It will be important in the future to investigate the effects of these multiple stressors on wildlife and local people to better predict the individual-level health risks. It is within this framework that One Health approaches offer promising opportunities to survey and pinpoint environmental changes that have effects on wildlife and human health.