Health of herring gulls (Larus argentatus) in relation to breeding location in the early 1990s. I. Biochemical measures

Investigation of the nephrotoxicity of 2,6-dichloro-1,4-benzoquinone disinfection by-product in mice through a 28-day toxicity test

In recent years, 2,6-dichloro-1,4-benzoquinone (DCBQ) has become an emerging water disinfection by-product and widely distributed in disinfected water. Although kidney is a potential target of DCBQ, a systematic study of the in vivo nephrotoxicity of DCBQ is rare. In this study, a 28-day oral toxicity test was used to assess the nephrotoxic effects of DCBQ on mice. And the potential mechanisms of nephrotoxicity induced by DCBQ were explored through inflammation, oxidative stress, apoptosis and gut microbiota. The results showed that the kidney indexes of mice were not altered in DCBQ-exposed group in comparison with the control group. The histopathological investigation revealed that DCBQ caused swollen of renal tube, destruction of the renal structure, and infiltration of inflammatory cell in kidney. DCBQ has induced oxidative damage in kidney, as the observation of the increase of the renal superoxide dismutase (SOD) and catalase (CAT) activity. Also, DCBQ has triggered the inflammatory response in kidney through the increased expression of IL-1β, NF-κB and iNOS. Moreover, DCBQ has activated the apoptosis pathway, as indicated by the increased mRNA expression of Caspase-3 and Caspase-9. We eventually found an association between gut microbiota and nephrotoxic variables, demonstrating the importance of gut-kidney axis in DCBQ toxicity. Our results suggested that exposure to DCBQ in disinfected water might be a risk factor for kidney and provided novel insights into the underlying mechanisms of DCBQ-induced kidney injury, contributing to better interpretation of the health impact of the environmentally emerging contaminant DCBQ.

Associations between serum polychlorinated biphenyls, halogen flame retardants, and renal function indexes in residents of an e-waste recycling area

E-waste handling activities release large quantities of polychlorinated biphenyls (PCBs) and halogen flame retardants (HFRs) into the surrounding area, creating a high exposure risk for local residents. However, the possibility of PCBs and HFRs exposure contributing to renal injury has not been extensively studied. To fill this knowledge gap, we conducted an epidemiological analysis of adolescents and adults recruited from an e-waste recycling area and a control area. Some PCBs and HFRs compounds were statistically significantly associated with the levels of β₂-microglobulin (β₂-MG), blood urea nitrogen (BUN), serum creatinine (SCr), and uric acid, with thyroid hormone-related genes found to partly mediate these associations. The interactions of PCBs and HFRs with metals also influenced renal function indexes. Exposure to high concentrations of PCBs and HFRs resulted in higher levels of β₂-MG and lower levels of BUN and SCr in the exposed group. As indicated by the elevated β₂-MG levels, high exposure to PCBs and HFRs may increase the risk of early renal injury for adolescents. These findings help to clarify the impacts of PCBs and HFRs on renal function and highlight the need to protect the health of residents in regions impacted by e-waste handling activities.

Differences in Trophic Level, Contaminant Load, and DNA Damage in an Urban and a Remote Herring Gull (Larus argentatus) Breeding Colony in Coastal Norway

Herring gulls (Larus argentatus) are opportunistic feeders, resulting in contaminant exposure depending on area and habitat. We compared contaminant concentrations and dietary markers between two herring gull breeding colonies with different distances to extensive human activity and presumed contaminant exposure from the local marine diet. Furthermore, we investigated the integrity of DNA in white blood cells and sensitivity to oxidative stress. We analyzed blood from 15 herring gulls from each colony-the urban Oslofjord near the Norwegian capital Oslo in the temperate region and the remote Hornøya island in northern Norway, on the Barents Sea coast. Based on d¹³ C and d³⁴ S, the dietary sources of urban gulls differed, with some individuals having a marine and others a more terrestrial dietary signal. All remote gulls had a marine dietary signal and higher relative trophic level than the urban marine feeding gulls. Concentrations (mean ± standard deviation [SD]) of most persistent organic pollutants, such as polychlorinated biphenyl ethers (PCBs) and perfluorooctane sulfonic acid (PFOS), were higher in urban marine (PCB153 17 ± 17 ng/g wet weight, PFOS 25 ± 21 ng/g wet wt) than urban terrestrial feeders (PCB153 3.7 ± 2.4 ng/g wet wt, PFOS 6.7 ± 10 ng/g wet wt). Despite feeding at a higher trophic level (d¹⁵ N), the remote gulls (PCB153 17 ± 1221 ng/g wet wt, PFOS 19 ± 1421 ng/g wet wt) were similar to the urban marine feeders. Cyclic volatile methyl siloxanes were detected in only a few gulls, except for decamethylcyclopentasiloxane in the urban colony, which was found in 12 of 13 gulls. Only hexachlorobenzene was present in higher concentrations in the remote (2.6 ± 0.42 ng/g wet wt) compared with the urban colony (0.34 ± 0.33 ng/g wet wt). Baseline and induced DNA damage (doublestreak breaks) was higher in urban than in remote gulls for both terrestrial and marine feeders. Environ Toxicol Chem 2022;41:2466-2478. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Maternal transfer and occurrence of siloxanes, chlorinated paraffins, metals, PFAS and legacy POPs in herring gulls (Larus argentatus) of different urban influence

Urban herring gulls (Larus argentatus) are exposed to contaminants from aquatic, terrestrial and anthropogenic sources. We aim to assess if differences in urbanisation affect ecological niche and contaminant concentrations in female herring gulls. Furthermore, we investigated maternal transfer from mothers to eggs for all the target compounds, including chlorinated paraffins (CPs) and cyclic volatile methyl siloxane (cVMSs), which to our knowledge have not been assessed in herring gulls previously. We compare concentrations of legacy and emerging contaminants and metals in blood and eggs between two herring gull colonies located 51 km apart, in the urban influenced Norwegian Oslofjord. While both colonies are within an urbanised area, the inner fjord is more so, as it is surrounded by Oslo, the capital and largest city in Norway Stable isotopes of carbon and nitrogen indicated a more marine ecological niche in the outer than the inner fjord colony, although with overlap. Persistent organic pollutant (POP) concentrations were similar in the inner and outer fjord colonies, while the short-chained chlorinated paraffins (SCCP), which are recently added to the Stockholm convention and contaminants of emerging concern (CECs) varied, with higher concentrations of SCCP and the cVMS decamethylcyclopentasiloxane (D5) in females and eggs of the inner fjord colony. Per- and polyfluorinated substances (PFAS) concentrations were higher in the outer fjord colony, likely linked to releases from a point-source (airport and waste management facility with open access to food waste). In blood, chlorinated paraffins contributed most the total lipophilic contaminants (inner: 78%, outer: 56%), while polychlorinated biphenyls (PCBs) were the most abundant lipophilic contaminants in eggs (inner: 62%, outer: 46%). Dechloranes and brominated flame retardants (BFRs) were detected in few samples. Maternal transfer, assessed by egg to blood ratios, of cVMSs were similar to the POPs with mean log ratio 0.39 (D5), while it was lower for SCCPs, with log ratios-0.77. Our results indicate comparable POP exposure of the herring gulls in the inner and outer Oslofjord, likely due to overlap in ecological niches between the colonies and wide distribution of POPs. The differences between the colonies in concentrations of PFAS, cVMS and CPs shows that point source exposures and urban influence may be more important than ecological niche for these compounds.

Anti-parasite treatment and blood biochemistry in raptor nestlings

We investigated the effects of parasite removal on various blood clinical–chemical variables (BCCVs). BCCVs are indicators of health, reflecting, e.g., homeostasis of liver, kidney function, and bone metabolism. The study was conducted in Norway on chicks of two predatory birds: White-tailed Eagle (Haliaeetus albicilla (L., 1758)) and Northern Goshawk (Accipiter gentilis (L., 1758)). Chicks were treated against both endoparasites (internal parasites) and ectoparasites (external parasites). We treated against ectoparasites by spraying nests with pyrethrins. Within nests, chicks were randomly treated with either an anti-helminthic medication (fenbendazole) or sterile water (controls). Treatment against either ectoparasites or endoparasites led to higher levels of the bone and liver enzyme alkaline phosphatase. Bilirubin levels were lower when treated against ectoparasites, whereas bile acids were higher. Anti-endoparasite treatment led to higher creatinine levels. In Northern Goshawks, treating against endoparasites led to higher urea levels and lower potassium levels. Treatment against ectoparasites increased uric acid and urea levels and reduced bilirubin levels and protein:creatinine ratios. In conclusion, anti-parasite treatments led to changes in several BCCVs, suggesting differences in nutrient absorption and physiological state of chicks that are possibly related to the costs of parasitism, but maybe also to the parasite treatment itself.

Thyroid Hormones, Retinol and Clinical Parameters in Relation to Mercury and Organohalogen Contaminants in Great Blue Heron (Ardea herodias) Nestlings from the St. Lawrence River, Québec, Canada

The exposure and effects of persistent environmental contaminants were investigated in great blue heron (Ardea herodias) nestlings sampled in 2001, 2002, 2006, and 2007 in freshwater and estuarine heronries along the St. Lawrence River, Québec (Canada). Biomarkers (retinoids, thyroid hormones, and clinical parameters) and contaminants (organochlorine contaminants, polychlorinated biphenyls (PCBs), brominated flame retardants (BFRs), and mercury (Hg)) were analyzed in blood, and Hg was analyzed in feathers (generally 9 nestlings per colony and 4 colonies per year). Feather Hg and most contaminants detected in blood were found in higher concentrations in birds from freshwater than estuarine colonies more distant from the pollution sources. Among freshwater colonies, Ile aux Hérons showed the highest levels of contaminants, with mean Hg concentrations of 8.4 and 0.55 mg/kg in feathers and plasma, respectively, and plasma ΣBFRs of 19.6 ng/g ww. The highest mean ΣPCBs, 56.5 ng/g ww, was measured at Grande Ile in 2001. The levels of contaminants in heron nestlings were generally below critical thresholds for adverse effects observed on reproduction or survival. Retinol, dehydroretinol (DROH), and thyroid hormone concentrations differed significantly among colonies. Retinol concentrations were negatively related to ΣPCBs, whereas DROH concentrations were negatively related to Hg and total and free triiodothyronine (T₃) concentrations were negatively related to ΣBFRs. These results indicate that contaminants from the St. Lawrence River could impair the development and fitness of great blue heron nestlings and emphasize the need for more research on the great blue heron population to assess their health and nutritional status.

Associations between organohalogen concentrations and transcription of thyroid-related genes in a highly contaminated gull population

A number of studies have reported altered circulating thyroid hormone levels in birds exposed either in controlled settings or in their natural habitat to ubiquitous organohalogen compounds including organochlorines (OCs) and polybrominated diphenyl ether (PBDE) flame retardants. However, limited attention has been paid to underlying homeostatic mechanisms in wild birds such as changes in the expression of genes in the hypothalamic-pituitary-thyroid (HPT) axis. The objective of the present study was to investigate the relationships between hepatic concentrations of major organohalogens (PBDEs and OCs), and circulating thyroid hormone (free and total thyroxine (T4) and triiodothyronine (T3)) levels and transcription of 14 thyroid-related genes in three tissues (thyroid, brain, and liver) of an urban-adapted bird exposed to high organohalogen concentrations in the Montreal area (QC, Canada), the ring-billed gull (Larus delawarensis). Positive correlations were found between liver concentrations of several polychlorinated biphenyls (PCBs), PBDEs as well as chlordanes and total plasma T4 levels. Hepatic concentrations of several PBDEs were negatively correlated with mRNA levels of deiodinase type 3, thyroid peroxidase, and thyroid hormone receptor β (TRβ) in the thyroid gland. Liver PCB (deca-CB) correlated positively with mRNA levels of sodium-iodide symporter and TRα. In brain, concentrations of most PBDEs were positively correlated with mRNA levels of organic anion transporter protein 1C1 and transthyretin, while PCBs positively correlated with expression of TRα and TRβ as well as deiodinase type 2. These multiple correlative linkages suggest that organohalogens operate through several mechanisms (direct or compensatory) involving gene transcription, thus potentially perturbing the HPT axis of this highly organohalogen-contaminated ring-billed gull population.

HEMATOLOGIC AND BIOCHEMICAL PARAMETERS OF KELP GULLS (LARUS DOMINICANUS) CAPTURED IN THE CITY OF TALCAHUANO, CHILE

In order to provide tools for future health-based monitoring programs, we developed reference intervals for hematology and plasma biochemistry and partitioned data for sex and season (winter and autumn). Ninety-one physically healthy kelp gulls (Larus dominicanus) were sampled in the city of Talcahuano, Chile, during winter (July-September) of 2007, autumn (April-June) and winter of 2008, and autumn of 2009. After blood sampling, the kelp gulls were euthanized by cervical dislocation. Packed cell volume (PCV), hemoglobin, total plasma protein (TPP), and complete blood count were performed. Alanine amino transferase, gamma-glutamyl transpeptidase, lactate dehydrogenase, alkaline phosphatase (ALP), creatinine, urea, calcium, phosphorus, and uric acid were analyzed. No significant differences were found between sexes (P>0.05). When a comparison was made between the two seasons, the values of PCV, TPP, white blood cell, heterophils, eosinophils, and monocytes were significantly higher in winter than in autumn (P<0.05) while and urea and uric acid concentrations were higher in autumn. Heterophils were the predominant circulating leukocyte for all birds. There was no significant difference in body condition between autumn and winter nor between sexes. Body condition showed a significant relationship with TPP and basophil concentration and ALP activity.

Organohalogen contaminants and Blood plasma clinical-chemical parameters in three colonies of North Atlantic Great skua (Stercorarius skua)

The present study compares blood plasma clinical-chemical parameters (BCCPs) in birds from three geographically distinct North Atlantic Great skua (Stercorarius skua) colonies. Birds from these sites bioaccumulate different POP (persistent organic pollutant) concentrations and that enabled us to compare Great skua BCCPs in different exposure scenarios. Persistent organic pollutants (organochlorines: PCB, DDT, chlordanes, HCB, HCH, mirex and brominated flame retardants: PBDEs) and nineteen BCCPs were analysed in 114 adult Great skuas sampled during summer 2009 in North Atlantic colonies at Bjørnøya (n=42), Iceland (n=57) and Shetland (n=15). Specimens from Bjørnøya had the highest blood plasma concentrations of all contaminant groups followed by Iceland and Shetland birds, respectively (ANOVA: p<0.05). Most of the 19 BCCP parameters followed the pattern of colony differences found for contaminants, with Bjørnøya having the highest concentrations. However seven BCCPs, the three liver enzymes ALKP, ALAT and GGT as well as bile acids, cholesterol, sodium and potassium, did not differ between colonies (ANOVA: p>0.05). Therefore correlation analyses of these seven BCCPs vs. POPs were done on the combined colony data while the analyses of the remaining 12 BCCPs were carried out for each colony separately. The analyses of combined colony data showed that the blood plasma concentration of liver enzymes ALAT and GGT increased with increasing concentrations of ΣPBDE and ΣHCH, HCB and ΣCHL, respectively (all Pearson's p<0.05). In Great skuas from Shetland, the important osmotic transport protein albumin increased with increasing concentrations of ΣPCB and ΣDDT, while total blood plasma protein increased with ΣPCB, ΣDDT, ΣHCH and HCB concentrations (all Pearson's p<0.05). In both Bjørnøya and Iceland skuas, blood plasma pancreatic enzyme amylase decreased with increasing ΣHCH concentrations while the erythrocyte waste product total bilirubin in blood plasma increased with increasing ΣHCH and ΣPBDE concentrations in Iceland Great skuas (all Pearson's p<0.05). In Bjørnøya birds, blood plasma urea from protein metabolism (reflects kidney function) increased with increasing ΣPBDE concentrations (Pearson's p<0.05). Furthermore, a redundancy analysis showed that 10.6% of the variations in BCCPs could be explained by the variations in POP concentrations. Based on these results we suggest that liver and renal functions could be negatively affected by different POP compounds. It is, however, uncertain if the colony BCCP differences and their relationship to POP concentrations reflect health effects that could have an overall impact on the populations via reduced survival and reproduction parameters.

Immunological and reproductive health assessment in herring gulls and black-crowned night herons in the Hudson-Raritan Estuary

Previous studies have shown inexplicable declines in breeding waterbirds within western New York/New Jersey Harbor between 1996 and 2002 and elevated polychlorinated dibenzo-p-dioxins and polychlorinated biphenyls (PCBs) in double-crested cormorant (Phalacrocorax auritus) eggs. The present study assessed associations between immune function, prefledgling survival, and selected organochlorine compounds and metals in herring gulls (Larus argentatus) and black-crowned night herons (Nycticorax nycticorax) in lower New York Harbor during 2003. In pipping gull embryos, lymphoid cells were counted in the thymus and bursa of Fabricius (sites of T and B lymphocyte maturation, respectively). The phytohemagglutinin (PHA) skin response assessed T cell function in gull and heron chicks. Lymphocyte proliferation was measured in vitro in adult and prefledgling gulls. Reference data came from the Great Lakes and Bay of Fundy. Survival of prefledgling gulls was poor, with only 0.68 and 0.5 chicks per nest surviving to three and four weeks after hatch, respectively. Developing lymphoid cells were reduced 51% in the thymus and 42% in the bursa of gull embryos from New York Harbor. In vitro lymphocyte assays demonstrated reduced spontaneous proliferation, reduced T cell mitogen-induced proliferation, and increased B cell mitogen-induced proliferation in gull chicks from New York Harbor. The PHA skin response was suppressed 70 to 80% in gull and heron chicks. Strong negative correlations (r = -0.95 to -0.98) between the PHA response and dioxins and PCBs in gull livers was strong evidence suggesting that these chemicals contribute significantly to immunosuppression in New York Harbor waterbirds.

Blood plasma clinical-chemical parameters as biomarker endpoints for organohalogen contaminant exposure in Norwegian raptor nestlings

Raptors are exposed to biomagnifying and toxic organohalogenated compounds (OHCs) such as organochlorines, brominated flame retardants and perfluorinated compounds. To investigate how OHC exposure may affect biochemical pathways we collected blood plasma from Norwegian northern goshawk (n=56), golden eagle (n=12) and white-tailed eagle (n=36) nestlings during three consecutive breeding seasons. We found that blood plasma concentrations of calcium, sodium, creatinine, cholesterol, albumin, total protein, urea, inorganic phosphate, protein:creatinine, urea:creatinine and uric acid:creatinine ratios and liver enzymes ALKP and ALAT were positively correlated to PCBs, chlordanes, p,p'-DDE, HCB, PFCs and/or PBDEs. Total bilirubin and glucose were negatively correlated to PCBs while magnesium and potassium were negatively correlated to HCB and p,p'-DDE. In addition, protein:creatinine and ALAT were also negatively correlated to PCBs and PFCs, respectively. The most significant relationships were found for the highly contaminated northern goshawks and white-tailed eagles. The statistical relationships between OHCs and BCCPs indicate that biochemical pathways could be influenced while it is uncertain if such changes have any health effects. The OHC concentrations were below concentrations causing reproductive toxicity in adults of other raptor species but similar to those of concern for endocrine disruption of thyroid hormones in e.g., bald eagles.

Mercury levels and health parameters in the threatened Olrog's Gull (Larus atlanticus) from Argentina

Mercury (Hg) exposure was investigated through feathers of Olrog's Gull and related to health parameters in adults (hematocrit, total plasma proteins, morphometric measures, sex) and chicks (hematocrit, total plasma proteins, immunoglobulins G and M) from a colony located in estuary of Bahía Blanca, Argentina. Mercury concentrations were 5.50 ± 2.59 μg g⁻¹ (n = 44) in live adults, 1.85 ± 0.45 μg g⁻¹ (n = 45) in live chicks and 1.81 ± 0.41 μg g⁻¹ (n = 41) in dead chicks. Large differences were observed between live adults and live or dead chicks and small differences between live and dead chicks. In the adults, the sex of the birds was the variable that best explained Hg concentrations. Male birds had higher concentrations than females; this suggests that the clutch provides a sink for mercury during egg laying. Hg concentrations in both adults and live chicks were associated with higher hematocrits. This could be associated with upregulated erythropoiesis to compensate for increased rate of destruction of prematurely senescent, Hg-contaminated erythrocytes. Based on our results, on the levels of Hg pollution in the past in the study area, and on the dietary specialization of Olrog's Gull, we must be vigilant about potential negative effects of Hg pollution on this population and recommend continued monitoring on this threatened species.

Effects of exposure to halogenated organic compounds combined with dietary restrictions on the antioxidant defense system in herring gull chicks

The Herring gull (HG) (Larus argentatus) is naturally exposed to halogenated organic compounds such as polychlorinated biphenyls (PCBs) through its diet. During periods of food scarcity, arctic seabirds experience lipid mobilization, allowing stored lipid soluble contaminants to re-enter the body circulation. In the present study, we investigated the effects of PCB exposure and fasting on the antioxidant defense system in HG chicks. Forty newly hatched chicks were exposed to contaminated cod liver oil for 6weeks and then fasted for 1week. We assessed the hepatic total oxyradical scavenging capacity (TOSC) against peroxynitrite, hydroxyl and peroxyl radicals, and measured glutathione (reduced: GSH, and oxidized: GSSG) levels and the enzymatic activities of catalase, glutathione peroxidase, glutathione reductase and superoxide dismutase. The results show that fasting significantly increased the HOC levels in the HG chick livers. Limited effects were observed on antioxidant responses; significant effects were only found for catalase (CAT) activity, Se-dependent GPX activity and the GSH/GSSG ratio in the exposed and fasted group. CAT and Se-dependent GPX activities correlated negatively with the PCB concentrations within this group, and a nonlinear relationship between glutathione and contaminant levels was also found. These effects were generally not observed after exposure or fasting alone and were likely related to the high PCB levels induced by the combination of exposure and fasting.

Endocrine disrupting, haematological and biochemical effects of polybrominated diphenyl ethers in a terrestrial songbird, the European starling (Sturnus vulgaris)

We exposed female European starlings (Sturnus vulgaris) during a 6month period to environmentally relevant concentrations of a pentabromodiphenyl ether (Penta-BDE) mixture (about 1740μg/kg body weight) through subcutaneous implants, and examined endocrine disruptive, haematological and biochemical effects. To investigate endocrine disrupting effects of PBDEs, testosterone, estradiol and thyroid hormones (T(3) and T(4)) were measured in the plasma. We found no significant differences between the control and exposed groups for any of the hormones. However, 14days after implantation, T(3) concentrations tended to be lower in the exposed group compared to the control group. For albumin, our results suggest that short term exposure of PBDEs may result in a negative effect on albumin, while the opposite was observed on a longer term (6months after implantation). However, from the statistical analysis, effects on albumin disappeared when excluding females that laid eggs. These results demonstrate that observed effects during the breeding season should be interpreted carefully when the breeding status of females is unknown. There were no significant differences found between the control and exposed groups for the other biochemical parameters (total protein, uric acid, cholesterol, aspartate transaminase, total antioxidative capacity, high-density lipoproteins and creatine kinase) and haematological parameters (amount of red blood cells, haemoglobin concentration, haematocrit, mean corpuscular volume and mean corpuscular haemoglobin). All together, our results suggest that European starlings, similar to other passerine species, may be less sensitive to the effects of organohalogenated pollutants, such as PBDEs, than other bird species.

Mercury contamination in spotted seatrout, Cynoscion nebulosus: an assessment of liver, kidney, blood, and nervous system health

Marine fishes in South Florida (Florida Keys-Florida Bay-Everglades region) accumulate higher concentrations of mercury (Hg) in their tissues than similar fishes from other areas of the southeastern U.S., though it is not known whether these elevated levels affect fish health. In this study, we used quantifiable pathological and biochemical indicators to explore Hg-associated differences in marine fish from South Florida, where Hg contamination is high, and from Indian River Lagoon, Florida, which served as a reference area. Hg concentrations in all tissues of mature spotted seatrout (Cynoscion nebulosus) from South Florida were significantly higher than those from Indian River Lagoon and were within the threshold range of those in studies where effects of Hg exposure have been observed. The distribution of Hg among tissues followed the same trend in both areas, with the greatest concentration in kidney tissue, followed by liver, muscle, brain, gonad, and red blood cells. Blood-plasma biochemistry showed that concentrations of iron, inorganic phosphate, lactate dehydrogenase, and aspartate aminotransferase were significantly less in South Florida. Also, fructosamine and alkaline phosphatase were significantly less in South Florida. Liver histology revealed that pyknosis/necrosis, interstitial inflammation, and bile duct hyperplasia were found only in seatrout from South Florida, and steatosis/glycogen was more frequently found in Indian River Lagoon specimens. In renal tissue, interstitial inflammation, glomerular dilatation and thickening, and tubular degeneration and necrosis were more frequently found in South Florida specimens. Changes in the liver cytoskeleton and morphology may explain some of the differences in blood parameters between study areas. Neurochemical analyses showed that brain N-methyl-d-aspartic acid (NMDA) receptors (but not those of muscarinic cholinergic receptors, monoamine oxidase, or acetylcholinesterase) were significantly less in fish from South Florida than from Indian River Lagoon. These findings provide compelling evidence that elevated Hg could cause quantifiable pathological and biochemical changes that might influence the health of spotted seatrout and could also affect other marine fish species.

Health effects from long-range transported contaminants in Arctic top predators: An integrated review based on studies of polar bears and relevant model species

The aim of this review is to provide a thorough overview of the health effects from the complexed biomagnified mixture of long-range transported industrial organochlorines (OCs), polybrominated diphenyl ethers (PBDEs), perfluorinated compounds (PFCs) and mercury (Hg) on polar bear (Ursus maritimus) health. Multiple scientific studies of polar bears indicate negative relationships between exposure to these contaminants and health parameters; however, these are all of a correlative nature and do not represent true cause-and-effects. Therefore, information from controlled studies of farmed Norwegian Arctic foxes (Vulpes lagopus) and housed East and West Greenland sledge dogs (Canis familiaris) were included as supportive weight of evidence in the clarification of contaminant exposure and health effects in polar bears. The review showed that hormone and vitamin concentrations, liver, kidney and thyroid gland morphology as well as reproductive and immune systems of polar bears are likely to be influenced by contaminant exposure. Furthermore, exclusively based on polar bear contaminant studies, bone density reduction and neurochemical disruption and DNA hypomethylation of the brain stem seemed to occur. The range of tissue concentration, at which these alterations were observed in polar bears, were ca. 1-70,000 ng/g lw for OCs (blood plasma concentrations of some PCB metabolites even higher), ca. 1-1000 ng/g lw for PBDEs and for PFCs and Hg 114-3052 ng/g ww and 0.1-50 microg/g ww, respectively. Similar concentrations were found in farmed foxes and housed sledge dogs while the lack of dose response designs did not allow an estimation of threshold levels for oral exposure and accumulated tissue concentrations. Nor was it possible to pinpoint a specific group of contaminants being more important than others nor analyze their interactions. For East Greenland polar bears the corresponding daily SigmaOC and SigmaPBDE oral exposure was estimated to be 35 and 0.34 microg/kg body weight, respectively. Furthermore, PFC concentrations, at which population effect levels could occur, are likely to be reached around year 2012 for the East Greenland polar bear subpopulation if current increasing temporal trends continue. Such proposed reproductive population effects were supported by physiological based pharmacokinetic (PBPK) modelling of critical body residues (CBR) with risk quotients >or=1 for SigmaPCB, dieldrin, SigmaPFC and SigmaOHC (organohalogen contaminant). The estimated daily TEQ for East Greenland polar bears and East Greenland sledge dogs were 32-281-folds above WHO SigmaTEQ guidelines for humans. Compared to human tolerable daily intake (TDI), these were exceeded for PCBs, dieldrin, chlordanes and SigmaHCH in East Greenland polar bears. Comparisons like these should be done with caution, but together with the CBR modelling and T-score estimations, these were the only available tools for polar bear risk evaluation. In conclusion, polar bears seem to be susceptible to contaminant induced stress that may have an overall sub-clinical impact on their health and population status via impacts on their immune and reproductive systems.

Polyhalogenated aromatic hydrocarbons and metabolites: Relation to circulating thyroid hormone and retinol in nestling bald eagles (Haliaeetus leucocephalus)

Polyhalogenated aromatic hydrocarbons are global contaminants that are often considered to be endocrine disruptors and include 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (p,p'-DDE), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). The present study examined these compounds and their hydroxylated metabolites or analogues and relationships with circulating thyroid hormones and retinols in plasma from nestling and adult bald eagles in British Columbia, Canada, and California, USA. We also compared our results with published data. Thyroxine (T4) decreased with summation operatorPCB and CB153 in nestling bald eagles, which was congruent with results from nine of 14 other published avian laboratory and field studies. Free thyroid hormone levels also decreased with CB-153 and hydroxylated PCBs (OH-PCBs). Retinol increased with CB118 and CB180 in nestling eagles, decreased with OH-PCBs in a subset of nestlings, and decreased in 7 of 12 PCB published studies. Thyroxine decreased with p,p'-DDE for nestlings and with data reported in one of five other published studies. In our samples, plasma retinol, triiodothyronine (T3), and T4 were independent of summation operatorPBDEs, whereas summation operatorOH-PBDEs were weakly but significantly correlated with increases in T3 and retinol. Adult bald eagles showed no relationship between contaminants and thyroid hormones, which is consistent with other studies of long-lived birds, perhaps because adult birds have time to adjust to contaminant levels. Measurement of circulating thyroid hormones appears to be a more useful biomarker than retinols, given the more consistent response of T4 to PCBs here and reported in the literature. We conclude that current environmental exposures to PCBs in British Columbia and in southern California are associated with significant decreases in T4, suggesting a potential negative effect on the endocrine system of nestling bald eagles.

Relationships between organohalogen contaminants and blood plasma clinical-chemical parameters in chicks of three raptor species from Northern Norway

Organohalogen contaminants (OHCs) may affect various physiological parameters in birds including blood chemistry. We therefore examined blood plasma clinical-chemical parameters and OHCs in golden eagle, white-tailed eagle and goshawk chicks from Northern Norway. Correlation analyses on pooled data showed that alkaline phosphatase (ALKP), glucose and creatinine were significantly negatively correlated to various OHCs (all: p<0.05; r: -0.43 to -0.55; n=23), while alanine aminotransferase (ALAT), total protein, cholesterol, uric acid, total bilirubin, ratios protein:creatinine and uric acid:creatinine were significantly positively correlated to various OHCs (all: p<0.05; r: 0.43-0.96). Based on these relationships, we suggest that the OHC concentrations found in certain raptor chicks of Northern Scandinavia may impact blood plasma biochemistry in a way that indicates impacts on liver, kidney, bone, endocrinology and metabolism. In order to elaborate further on these relationships and mechanisms, we recommend that a larger study should take place in the near future.

The Svalbard glaucous gull as bioindicator species in the European arctic: insight from 35 years of contaminants research

Biomonitoring survey conducted with glaucous gulls from Svalbard have demonstrated that this top-predator-scavenger species accumulates a wide array of chemicals of environmental concern, including organohalogens, trace elements, organometals, and several non-halogenated and non-metallic-compounds. Among these contaminants are those subjected to global bans or restrictions in North America and Europe (e.g., legacy OC's, penta-, and octa-PBDE technical mixtures and mercury). In addition, some currently produced chemicals were found in gulls that lack and global use regulation (e.g., deca-PBDE , HBCD, and other non-PBDE BFR additives, siloxanes, and selected PFASs). Svalbard glaucous gulls are also exposed to contaminant metabolites that, at time, are more bioactive than their precursors (e.g., oxychlordane, p,p'-DDE, OH- and MeSo2-PCBs, and OH-PBDEs) Concentrations of legacy OCs (PCBs, DDTs, CHLs, CBzs, dieldrin, PCDD/Fs, and mirec) in tissues, blood, and eggs of Svalbard glaucous gulls have displayed the highest contamination levels among glaucous gull populations that inhabit Greenland (Cleemann et al. 2000) Jan Mayen (Gabrielsen et al. 1997), Alaska (Vander Pol et al. 2009), and the Canadian Arctic (Braune et a. 2005). To date, measurements obtaines on more novel organohalogens (e.g., OH- and MeSo2-containing metabolites, BFRs and PFASs) in Svalbard glaucous gull samples generally confirm that the spatial and trophodynamic trends of the legacy OC concentrations, whereas no clear trend emerges from surveys of trace elements and organometals. Using the glaucous gull as biosentinel species provides clear evidence that Svalbard and the European Arctic environment is exposed to a complex mixture of legacy and more recently introduced PBT-like substances.

Seabirds as indicators of aquatic ecosystem conditions: a case for gathering multiple proxies of seabird health

The use of seabirds as sentinels of the condition of aquatic ecosystems has been well-established. Large environmental perturbations to aquatic food webs (e.g., chemical contamination, overfishing, particulate pollution) have all been detected or monitored by tracking seabirds at colonies. However, seabirds may elicit more subtle, sublethal responses that can also be used to track ecosystem health, or the health of seabird populations. In this article, we advocate for field researchers to plan a priori to collect a broader suite of samples when handling seabirds, and to reach out for collaboration with specialists (e.g., parasitologists, wildlife veterinarians). Collectively, such efforts will greatly improve our ability to establish baseline physiological and chemical levels for seabirds, against which we can detect future changes in aquatic ecosystems.

Fluctuating wing asymmetry and hepatic concentrations of persistent organic pollutants are associated in European shag (Phalacrocorax aristotelis) chicks

In aquatic birds, high body burdens of persistent organic pollutants (POPs) have been associated with developmental effects related to growth, increased fluctuating wing asymmetry, and disruption of the thyroid hormone, vitamin A (retinol) and vitamin E (tocopherol) homeostasis. The aim of the present study was to examine if morphological variables (body mass, liver mass, wing length, tarsus length and head length), fluctuating asymmetry of the wings and tarsus, growth rates and endocrine variables (thyroid hormones, retinol and tocopherol) were associated with hepatic levels of POPs (PCBs, OCPs and PBDEs) in 21 day old chicks of European shag (Phalacrocorax aristotelis). Partial Least Squares (PLS) analysis showed that fluctuating asymmetry of wing bone length (FA(WBL)) was affected by PCB-105, -118, -138, -153, and -180 (r(2)x=0.88, r(2)y=0.35, q(2)=0.29). Bivariate correlation confirmed significant positive relationships between FA(WBL) and each of these PCB congeners. In the PLS model no other biological variables were significantly affected by any of the POPs. Levels of POPs were much lower in the shag chicks than in eggs and in hatchlings from the same breeding colony, most likely due to growth dilution of the compounds. We suggest that the effects of the PCBs on FA(WBL) may be due to effects of these compounds on bone growth and bone structure. FA(WBL) may have functional effects on the fitness if it persists after fledging.

An overview of dioxin-like compounds, PCB, and pesticide exposures associated with sexual differentiation of neuroendocrine systems, fluctuating asymmetry, and behavioral effects in birds

Dioxin, polychlorinated biphenyls (PCBs), and pesticides impact neural systems in birds due to interference with sexual differentiation. Early endocrine disrupting chemical (EDC) effects may delay maturation and have long-term effects on lifetime reproduction, especially in precocial birds that complete sexual differentiation prior to hatch. Semi-altricial and altricial species appear more resilient to EDC effects and show a gradient in sensitivity, especially in the neuroplastic song system. Embryonic steroid exposure occurs via maternally deposited steroids followed by embryo produced hormones; EDCs potentially affect these developing systems. As such, EDCs can impact lifelong fitness by acting on neural systems that regulate reproduction, metabolism, and behavior.

Persistent organic pollutants, heavy metals and parasites in the glaucous gull (Larus hyperboreus) on Spitsbergen

The prediction of a higher parasite infection as a consequence of an impaired immune system with increasing persistent organic pollution (POP) and heavy metal levels were investigated in adult glaucous gull (Larus hyperboreus) from Svalbard. The levels of chlorinated pesticides, polychlorinated biphenyls (PCBs), toxaphenes and polybrominated diphenyl ethers (PBDEs) were measured in liver. Copper, cadmium, lead, mercury, selenium and zinc were measured in kidney samples. An elevated ratio of PCB-118 was found, suggesting that local contamination from the settlement was detectable in the glaucous gull. Eight cestodes, four nematodes, two acanthocephalan and three trematode helminth species were found in the intestine. A positive correlation was found between cestode intensities and selenium levels and between acanthocephalan intensities and mercury levels. No correlation was found between parasite intensities and POP concentrations. It is concluded that the contaminant levels found in glaucous gulls do not cause immune suppression severe enough to affect parasite intensity.

Health of herring gulls (Larus argentatus) in relation to breeding location in the early 1990s. III. Effects on the bone tissue

Health effects associated with the Great Lakes environment were assessed in adult herring gulls (Larus argentatus) in the early 1990s, including the size and quality of their bones. Femurs were excised from 140 individuals from 10 colonies distributed throughout the Great Lakes and 2 reference colonies in Lake Winnipeg (freshwater) and the Bay of Fundy (marine). Femurs of gulls from the Great Lakes differed from the freshwater or marine reference for 9 of 12 variables of size, composition, and strength assessed using peripheral quantitative computed tomography (pQCT) and biomechanical testing. Femurs of Great Lakes gulls were significantly smaller in length (-2.9%), periosteal circumference (-2.4%), and cross-sectional area (-5.4%) than freshwater reference birds. Femurs of the Great Lakes gulls had a lower significant cortical bone mineral content (-8.1%) and density (-2%) than the marine reference. A significant increase in the amount the bone could bend before it broke (+34%) and the energy required to break it (+44%) and a significant decrease (-16.3%) in stiffness during three-point biomechanical bending test were also detected in Great Lakes versus the freshwater gulls. These differences are indicative of impaired mineralization. When divided into high and low 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicity equivalent (TCDD-TEQ) colonies, the amount the bone could bend before it broke and the energy required to break it were significantly higher in the high TEQ colonies, but not high polychlorinated biphenyl (PCB) colonies. Breeding location and dietary choices of Great Lakes herring gulls in the early 1990s resulted in modulations of physiological processes that affected the size, mineralization, and biomechanical properties of bone.