Persistent organic pollutant levels and the importance of source proximity in Baltic and Svalbard breeding common eiders

Impacts of a warming climate on concentrations of organochlorines in a fasting high arctic marine bird: Direct vs. indirect effects?

The present study examined how climate changes may impact the concentrations of lipophilic organochlorines (OCs) in the blood of fasting High Arctic common eiders (Somateria mollissima) during incubation. Polychlorinated biphenyls (PCBs), 1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p'-DDE), hexachlorobenzene (HCB) and four chlordane compounds (oxychlordane, trans-chlordane and trans- and cis-nonachlor) were measured in females at chick hatching (n = 223) over 11 years (2007-2017). Firstly, median HCB and p,p'-DDE concentrations increased ~75 % over the study period, whereas median chlordane concentrations doubled (except for oxychlordane). PCB concentrations, in contrast, remained stable over the study period. Secondly, both body mass and clutch size were negatively associated with OC levels, suggesting that females with high lipid metabolism redistributed more OCs from adipose tissue, and that egg production is an important elimination route for OCs. Thirdly, the direct climate effects were assessed using the mean effective temperature (ET: air temperature and wind speed) during incubation, and we hypothesized that a low ET would increase redistribution of OCs. Contrary to expectation, the ET was positively correlated to most OCs, suggesting that a warmer climate may lead to higher OCs levels, and that the impact of ET may not be direct. Finally, potential indirect impacts were examined using the Arctic Oscillation (AO) in the three preceding winters (AOwinter 1-3) as a proxy for potential long-range transport of OCs, and for local spring climate conditions. In addition, we used chlorophyll a (Chla) as a measure of spring primary production. There were negative associations between AOwinter 1 and HCB, trans-chlordane and trans-nonachlor, whereas oxychlordane and cis-chlordane were negatively associated with Chla. This suggests that potential indirect climate effects on eiders were manifested through the food chain and not through increased long-range transport, although these relationships were relatively weak.

Common Eider and Herring Gull as Contaminant Indicators of Different Ecological Niches of an Urban Fjord System

Seabirds like gulls are common indicators in contaminant monitoring. The herring gull (Larus argentatus) is a generalist with a broad range of dietary sources, possibly introducing a weakness in its representativeness of aquatic contamination. To investigate the herring gull as an indicator of contamination in an urban-influenced fjord, the Norwegian Oslofjord, we compared concentrations of a range of lipophilic and protein-associated organohalogen contaminants (OHCs), Hg, and dietary markers in blood (n = 15), and eggs (n = 15) between the herring gull and the strict marine-feeding common eider (Somateria mollissima) in the breeding period of May 2017. Dietary markers showed that the herring gull was less representative of the marine food web than the common eider. We found higher concentrations of lipophilic OHCs (wet weight and lipid weight) and Hg (dry weight) in the blood of common eider (mean ± SE ∑PCB = 210 ± 126 ng/g ww, 60 600 ± 28 300 ng/g lw; mean Hg = 4.94 ± 0.438 ng/g dw) than of the herring gull (mean ± SE ∑PCB = 19.0 ± 15.6 ng/g ww, 1210 ± 1510 ng/g lw; mean Hg = 4.26 ± 0.438 ng/g dw). Eggs gave opposite results; higher wet weight and lipid weight OHC concentrations in the herring gull (mean ± SE ∑PCB = 257 ± 203 ng/g ww, 3240 ± 2610 ng/g lw) than the common eider (mean ± SE ∑PCB = 18.2 ± 20.8 ng/g ww, 101 ± 121 ng/g lw), resulting in higher OHC maternal transfer ratios in gulls than eiders. We suggest that the matrix differences are due to fasting during incubation in the common eider. We suggest that in urban areas, herring gull might not be representative as an indicator of marine contamination but rather urban contaminant exposure. The common eider is a better indicator of marine pollution in the Oslofjord. The results are influenced by the matrix choice, as breeding strategy affects lipid dynamics regarding the transfer of lipids and contaminants to eggs and remobilization of contaminants from lipids to blood during incubation, when blood is drawn from the mother. Our results illustrate the benefit of a multispecies approach for a thorough picture of contaminant status in urban marine ecosystems. Integr Environ Assess Manag 2021;17:422-433. © 2020 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Circulating trace elements: Comparison between early and late incubation in common eiders (Somateria mollissima) in the central Baltic Sea

We analyzed body mass and a panel of 64 trace elements in blood from incubating common eiders (Somateria mollissima) in the central Baltic Sea during the breeding seasons of 2017 (n = 27) and 2018 (n = 23). Using a non-invasive approach, the same incubating eiders nesting on Christiansø, Denmark were sampled once on day 4 and day 24 of incubation to provide a comparison between the early and late stages of incubation. Blood concentrations of chemical elements were quantified using high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). Cadmium and lead significantly increased over the course of the incubation period while body mass, barium, calcium, cerium, cesium, iron, magnesium, manganese, molybdenum, phosphorus, selenium, strontium, sulfur, uranium, and zinc all significantly decreased. Excluding lead, all trace elements were within expected ranges. Lead blood concentrations had a 4.7-fold increase from 2017 to 2018 indicating a potential health threat. However, internal interactions between trace elements must be considered when making comparisons to toxicological thresholds. Body mass and many essential elements showed significantly higher levels in 2017 than 2018, which could be an indication of limitations in preferred food availability or harsher fasting conditions. Additional sampling years are needed to further investigate if these results reflect yearly fluctuations or decreasing health within the Christiansø eider colony. There was little overlap in element blood concentrations and body mass between days of incubation, indicating these parameters are affected by the physiological processes of reproduction and incubation. We recommend continued biomonitoring and use of complete trace element analysis for the Christiansø eiders to further understand year-to-year variations within colonies. Further investigation into the spatial ecology of the colony is also needed to provide a more robust understanding of exposure and source identification of trace elements.

Temporal trends of legacy organochlorines in different white-tailed eagle (Haliaeetus albicilla) subpopulations: A retrospective investigation using archived feathers

Understanding the spatiotemporal patterns of legacy organochlorines (OCs) is often difficult because monitoring practices differ among studies, fragmented study periods, and unaccounted confounding by ecological variables. We therefore reconstructed long-term (1939-2015) and large-scale (West Greenland, Norway, and central Sweden) trends of major legacy OCs using white-tailed eagle (Haliaeetus albicilla) body feathers, to understand the exposure dynamics in regions with different contamination sources and concentrations, as well as the effectiveness of legislations. We included dietary proxies (δ¹³C and δ¹⁵N) in temporal trend models to control for potential dietary plasticity. Consistent with the hypothesised high local pollution sources, levels of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs) in the Swedish subpopulation exceeded those in the other subpopulations. In contrast, chlordanes (CHLs) and hexachlorobenzene (HCB) showed higher concentrations in Greenland, suggesting the importance of long-range transport. The models showed significantly decreasing trends for all OCs in Sweden in 1968-2011 except for CHLs, which only decreased since the 1980s. Nevertheless, median concentrations of DDTs and PCBs remained elevated in the Swedish subpopulation throughout the 1970s, suggesting that the decreases only commenced after the implementation of regulations during the 1970s. We observed significant trends of increasing concentrations of PCBs, CHLs and HCB in Norway from the 1930s to the 1970s/1980s and decreasing concentrations thereafter. All OC concentrations, except those of PCBs were generally significantly decreasing in the Greenland subpopulation in 1985-2013. All three subpopulations showed generally increasing proportions of the more persistent compounds (CB 153, p.p'-DDE and β-HCH) and decreasing proportions of the less persistent ones (CB 52, p.p'-DDT, α- and γ-HCH). Declining trends of OC concentrations may imply the decreasing influence of legacy OCs in these subpopulations. Finally, our results demonstrate the usefulness of archived museum feathers in retrospective monitoring of spatiotemporal trends of legacy OCs using birds of prey as sentinels.

Annual changes in concentrations and health risks of PCDD/Fs, DL-PCBs and organochlorine pesticides in ambient air based on the Global Monitoring Plan in São Paulo

Ambient air contains a number of persistent organic pollutants (POPs), to which inhalation exposure has drawn worldwide concern. However, information regarding annual changes in the concentrations and health risks of POPs in the ambient air of São Paulo, Brazil, are limited. This study provides comprehensive information on annual changes in polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (DL-PCBs), and 10 groups of organochlorine pesticides (OCPs) in the ambient air of São Paulo between 2010 and 2015 based on the Global Monitoring Plan. The mass concentrations of the studied POPs (PCDD/Fs, DL-PCBs, and OCPs) showed declining trends from 2010 to 2015 (from 2.65 × 10^-2 to 1.33 × 10^-2 pg m^-3, from 9.89 × 10^-2 to 3.12 × 10^-2 pg m^-3, and from 0.313 to 0.100 ng m^-3, respectively), which might be due to the decrease of non-intentional emissions. The carcinogenic risk (CR) and non-carcinogenic risk (Non-CR) of the studied POPs were 1.48 × 10^-11 to 6.08 × 10^-7 and 3.44 × 10^-8 to 3.34 × 10^-3, respectively, which are lower than the generally accepted threshold values (10^-6/10^-5 and 1 for CR and Non-CR, respectively), suggesting that the health risks posed by the studied POPs were acceptable. PCDD/Fs had the highest CR (6.08 × 10^-8-4.81 × 10^-7), whereas the 95th percentile CR of DL-PCBs and nine of the OCPs were lower than 10^-7, suggesting that among the studied POPs, PCDD/Fs in the ambient air warrant special attention. The 95th percentile CRs of dichlorodiphenyltrichloroethane (2.30 × 10^-8), dieldrin (1.30 × 10^-8), hexachlorocyclohexanes (1.05 × 10^-8), heptachlor (8.97 × 10^-9), hexachlorobenzene (6.47 × 10^-9), chlordane (5.89 × 10^-9), heptachlor epoxide (1.42 × 10^-9), aldrin (1.33 × 10^-9), and mirex (2.71 × 10^-10) in ambient air were relatively low, suggesting that their threats to human health were negligible. In general, PCDD/Fs, DL-PCBs, and OCPs in the ambient air of São Paulo did not pose serious threats to human health during 2010-2015.

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.

Individual variation of persistent organic pollutants in relation to stable isotope ratios, sex, reproductive phase and oxidative status in Scopoli's shearwaters (Calonectris diomedea) from the Southern Mediterranean

Little is known about the accumulation of persistent organic pollutants (POPs) and its consequences for seabirds in the Mediterranean basin. We characterised the plasma contaminant profile (polychlorinated biphenyls ΣPCBs; organochlorine pesticides ΣOCPs; polybrominated diphenyl ethers ΣPBDEs) of a population of the seabird Scopoli's shearwater (Calonectris diomedea) that breeds in the southern Mediterranean (Linosa Island) and investigated (i) whether sex, stable isotope ratios (related to diet), reproductive phase (early incubation vs. late breeding season) and body mass explained variation in contaminant burden and (ii) whether they predict health-related variables. The predominant category of POPs was ΣPCBs contributing between 53.0 and 92.4% of the total POPs in each shearwater. The percentage contribution of ΣOCPs to total POPs ranged between 7.6 and 47.0%, while that of ΣPBDEs ranged between <1% and 22.1%. Near the end of the breeding season, concentrations of ΣPCBs, ΣOCPs and ΣPOPs were significantly higher than at the beginning of the incubation period. ΣPBDEs were higher in males than females near the end of the breeding season, while they were higher in females than males at the beginning of the egg incubation period. Carbon- and nitrogen isotope ratios and individual body mass were not significantly associated with any contaminant class. Mates differed in the concentration of POPs, but they had similar stable isotope values. There was little evidence for a connection between contaminants and blood-based markers of oxidative balance. None of the contaminants predicted the probability of a bird being resighted as a breeder the following year. Thus, although POPs were present at high concentrations in some individuals, our study suggests little concern regarding POP exposure for this shearwater population.

Blood and feather concentrations of toxic elements in a Baltic and an Arctic seabird population

We report blood and feather concentrations of elements in the Baltic Sea and Arctic population of common eiders (Somateria mollissima). The endangered Baltic Sea population of eiders was demonstrably affected by element pollution in the 1990s. While blood concentrations of Hg were higher in Baltic breeding eiders, blood Se, As and Cd concentrations were higher in Arctic eiders. Blood concentrations of Pb, Cr, Zn and Cu did not differ between the two populations. While blood Pb concentrations had declined in Baltic eiders since the 1990s, Hg concentrations had not declined, and were above concentrations associated with adverse oxidative effects in other bird species. Inconsistent with blood concentrations, feather concentrations suggested that Pb, Zn, and Cd exposure was higher in Baltic eiders, and that Hg exposure was higher in Arctic eiders. Our study thus emphasizes the need for comprehensive evaluation of toxic element status, covering the annual cycle of a species.

DNA double-strand breaks in incubating female common eiders (Somateria mollissima): Comparison between a low and a high polluted area

Alterations in the genetic material may have severe consequences for individuals and populations. Hence, genotoxic effects of environmental exposure to pollutants are of great concern. We assessed the impact of blood concentrations of persistent organic pollutants (POPs) and mercury (Hg) on DNA double-strand break (DSB) frequency, in blood cells of a high-exposed Baltic, and lower exposed Arctic population of common eiders (Somateria mollissima). Furthermore, we examined whether the genotoxic response was influenced by antioxidant concentration (plasma total glutathione (tGSH) and total antioxidant capacity) and female body mass. The DNA DSB frequency did not differ between the two populations. We found significant positive relationships between Hg and DNA DSB frequency in Baltic, but not in Arctic eiders. Although both p,p'-DDE and PCB 118 had a lesser effect than Hg, they exhibited a positive association with DNA DSB frequency in Baltic eiders. Antioxidant levels were not important for the genotoxic effect, suggesting alternative mechanisms other than GSH depletion for the relationship between Hg and DNA DSBs. Hence, the Baltic population, which is considered to be endangered and is under the influence of several environmental stressors, may be more susceptible to genotoxic effects of environmental exposure to Hg than the Arctic population.

Antioxidant Responses in Relation to Persistent Organic Pollutants and Metals in a Low- and a High-Exposure Population of Seabirds

Oxidative stress occurs when there is an imbalance between the production of reactive oxygen species (ROS) and antioxidant defense. Exposure to pollutants may increase ROS and affect antioxidant levels, and the resulting oxidative stress may negatively affect both reproduction and survival. We measured concentrations of 18 persistent organic pollutants (POPs) and 9 toxic elements in blood, as well as total antioxidant capacity (TAC), total glutathione (tGSH), and carotenoids in plasma of Baltic and Arctic female common eiders (Somateria mollissima) (N = 54) at the end of their incubation-related fasting. The more polluted Baltic population had higher TAC and tGSH concentrations compared to the Arctic population. Carotenoid levels did not differ between populations. The effect of mixtures of pollutants on the antioxidants was assessed, and the summed molar blood concentrations of 14 POPs were positively related to TAC. There was no significant relationship between the analyzed pollutants and tGSH concentrations. The adaptive improvement of the antioxidant defense system in the Baltic population may be a consequence of increased oxidative stress. However, both increased oxidative stress and energy allocation toward antioxidant defense may have adverse consequences for Baltic eiders at the incubation stage, when energy resources reach an annual minimum due to incubation-related fasting.