Toxic element concentrations in the Razorbill Alca torda (Charadriiformes, Alcidae) in Portugal

Baseline metal and metalloid contamination in two marine sponge species, Hymeniacidon heliophila and Desmapsamma anchorata, from southeastern Brazil

Sponges are not routinely employed as metal bioindicators in Brazil. In this sense, this study reports baseline metal and metalloid concentrations, determined by inductively coupled plasma mass spectrometry, for two Demospongiae sponge species, Hymeniacidon heliophila and Desmapsamma anchorata, sampled from two Southeastern Brazil areas. Sponges from Ilha Grande Bay, an Environmental Protection Area, exhibited higher Al, As, Cd, Co, Cr, Fe, and Ni levels compared to Vermelha Beach, a metropolitan area in the Rio de Janeiro city. Several strong correlations were noted between elemental pairs, indicating common contamination sources and/or similar metabolic detoxification routes. Comparisons of the means determined herein for each study site to other reports indicate mostly lower Ag, As, Co, Cd, and Cu levels, while Al levels were higher than other studies, and Cr, Ni, and Fe were within reported ranges. These baseline data further knowledge on metal pollution in Desmspongiae members, which are still limited.

Heavy metal contamination in pristine environments: lessons from the Juan Fernandez fur seal (Arctocephalus philippii philippii)

Heavy metals, including mercury (Hg) and cadmium (Cd), occur naturally or anthropogenically and are considered toxic to the environment and human health. However, studies on heavy metal contamination focus on locations close to industrialized settlements, while isolated environments with little human activity are often ignored due to perceived low risk. This study reports heavy metal exposure in Juan Fernandez fur seals (JFFS), a marine mammal endemic to an isolated and relatively pristine archipelago off the coast of Chile. We found exceptionally high concentrations of Cd and Hg in JFFS faeces. Indeed, they are among the highest reported for any mammalian species. Following analysis of their prey, we concluded that diet is the most likely source of Cd contamination in JFFS. Furthermore, Cd appears to be absorbed and incorporated into JFFS bones. However, it was not associated with mineral changes observed in other species, suggesting Cd tolerance/adaptations in JFFS bones. The high levels of silicon found in JFFS bones may counteract the effects of Cd. These findings are relevant to biomedical research, food security and the treatment of heavy metal contamination. It also contributes to understanding the ecological role of JFFS and highlights the need for surveillance of apparently pristine environments.

Metal accumulation in juvenile and sub-adult loggerhead and green turtles in northern Cyprus

Sea turtles are considered pollution bioindicators due to their tendency to accumulate high metal levels in their tissues during their long lifespans. In this context, we aimed to analyse the concentrations of 12 elements in liver, kidney, heart and muscle samples from green turtles (Chelonia mydas; n = 41) and loggerhead turtles (Caretta caretta; n = 14) found stranded in Northern Cyprus. The samples were collected between 2019 and 2021, stored in sterile Eppendorf tubes at -20 °C until metal analysis, and analysed with an inductively coupled plasma mass spectrometer. With this study, we contribute to the limited number of studies on metal accumulation in heart tissue and present the first data for Mg accumulation in the heart, liver, muscle and kidney tissues of both species. We found that metal accumulation levels differed among the two study species' tissues, with some elements in the same tissue (Al_Kidney, As_Heart, As_Liver, Fe_Muscle, Fe_Kidney, Fe_Heart, Mn_Heart, Pb_Heart, Zn_Muscle and Zn_Kidney) significantly differing between species. The observed variation likely resulted from their different feeding habits, which cause them to be exposed to different levels of metals. We also found significant associations among elements within tissues, as well as between the same element across different tissues in both species, which may indicate the differential accumulation of elements among organs due to physiological processes in turtle metabolism, bioaccumulation or excretion.

Nurse sharks, space rockets and cargo ships: Metals and oxidative stress in a benthic, resident and large-sized mesopredator, Ginglymostoma cirratum

It is widely recognized that apex predators, such as large sharks with highly migratory behavior, are particularly vulnerable to pollution, mainly due to biomagnification processes. However, in highly impacted areas, mesopredator sharks with resident behavior can be as vulnerable as apex sharks. In this context, this study evaluated cadmium (Cd), mercury (Hg), lead (Pb), and rubidium (Rb) concentrations, as well as the potentially protective effects of selenium (Se) and the behavior of two non-enzymatic biomarkers, metallothionein (MT) and reduced glutathione (GSH), employing the Atlantic nurse shark Ginglymostoma cirratum as a study model and compared the results with other resident benthic sharks, as well as highly mobile apex sharks. Muscle tissue samples from 28 nurse sharks opportunistically sampled from the Brazilian Amazon Coast were analyzed. Lower metal concentrations were observed for Pb, Rb and Se in the rainy season, while statistically significant correlations between metals were observed only between Hg and Cd and Pb and Se. Molar ratio calculations indicate potential protective Se effects against Pb, but not against Cd and Hg. No associations between MT and the determined metals were observed, indicating a lack of detoxification processes via the MT detoxification route. The same was noted for GSH, indicating no induction of this primary cellular antioxidant defense. Our results indicate that benthic/mesopredator sharks with resident behavior are, in fact, as impacted as highly mobile apex predators, with the traditional detoxification pathways seemingly inefficient for the investigated species. Moreover, considering the studied population and other literature data, pollution should be listed as a threat to the species in future risk assessments.

Seabird droppings: Effects on a global and local level

Seabirds, with approximately 1 billion specimens, are the main exchangers of nutrients between Terrestial and Marine Systems and they have become an emerging interest group because of their effects on the planet's ecosystem. This review paper aims to highlight the impact of seabird droppings at different trophic levels, their occurrence, ecological risks and effects on soil, water, atmosphere and biota at global and local level to try to understand the ecological and climatic changes associated with the activities of these birds. Seabirds they have a very marked influence on the ecosystems where they form their colonies since, in addition to their function as predators, alongside with their depositions, they condition the primary producers and, consequently, the rest of the food chain. Their excrements contain large amounts of N, P and trace elements, most of which are bioavailable. In this study, besides bringing together the different works on nutrients and trace elements in excrements and differentiating some terms referring to these excrements, a brief historical overview of their importance for agriculture is made. In addition, the impacts produced by these birds on the ecosystem are also analysed according to two levels, at a global and local level. At each of these levels, a current state of the effects on the different compartments of the ecosystems is made, from the biota to the soils, the water or the atmosphere. This review supports the idea that more studies are needed both at the atmospheric level and in the terrestrial or marine environment for a better understanding of the changes these birds generate.

Gastrointestinal and respiratory exposure of water birds to endocrine disrupting phenolic compounds

Aquatic birds found at the top of the trophic chain are exposed to xenobiotics present both in food and inhaled air. The aim of this study was to indicate and assess the routes and levels of exposure of aquatic birds to bisphenol A (BPA), 4-tert-octylphenol (4-t-OP) and 4-nonylphenol (4-NP). The birds constituting the study material (Clangula hyemalis, Alca torda, Mergus merganser) originated from by-catches (winter 2014-2016) in the Southern Baltic. The studies show that the exposure of birds to phenol derivatives is determined by the specifics of a compound, the habitat area, trophic level and food consumed. BPA was characterized by the highest intestinal concentrations in all birds (6.6-1176.2 ng^.g^-1 dw). Higher concentrations of 4-t-OP were determined in the lungs of birds from the eastern part of the Southern Baltic (9.1-135.7 ng^.g^-1 dw) and in the intestines of birds from the western part (<0.5-191.4 ng^.g^-1 dw). In the case of 4-NP, higher concentrations were found in the intestines of carnivorous species (64.9-524.5 ng^.g^-1 dw), and the lungs of benthos-eating species (39.4-399.7 ng^.g^-1 dw). The intestines that were most burdened with 4-NP were those of birds from the highest trophic level. Correlations between the concentrations of phenol derivatives in the blood and the intestines and lungs indicated that birds are exposed to the penetration of phenol derivatives through the digestive and respiratory tracts. BPA and 4-NP were characterized by the highest concentrations in the intestines and lungs, whereas 4-t-OP in blood (3.2-39.2 ng^.cm^-3), which may indicate the largest endocrine potential of this compound in birds. Significant differences in phenol derivatives concentrations in the intestines and lungs of birds from the western and eastern part of the Southern Baltic, shows that these tissues can be useful for assessing the contamination of the environment with EDCs.

Cytosolic and Metallothionein-Bound Hepatic Metals and Detoxification in a Sentinel Teleost, Dules auriga, from Southern Rio de Janeiro, Brazil

Dules auriga, a native Brazilian teleost, was applied as a sentinel species regarding metal contamination at Ilha Grande Bay, previously considered a reference site in Southeastern Brazil. Cytosolic (S50) and metallothionein-bound (HTS50) hepatic iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), cadmium (Cd), and silver (Ag) were determined by inductively coupled plasma optical emission spectrometry (ICP-OES), while metallothionein (MT) concentrations were determined by polarography. Ag concentrations in both cytosolic fractions were below the limit of detection. All other HTS50 metal contents were significantly lower than S50 contents. No significant associations were found for MT. Fe and Mn S50 were positively and moderately correlated to total length, as well as HTS50 Mn, while total weight was correlated to both Mn fractions, suggesting that environmental Mn and Fe concentrations may influence fish growth. A moderate correlation between the condition factor and the S50 Cu fraction was observed, also indicating that Cu may affect fish growth. Inter-element correlations were observed, including between Cd, a toxic element, and Mn and Zn, both essential elements. Calculated molar ratios indicate that both Mn and Zn are in molar excesses compared with Cd, corroborating literature assessments regarding protective Mn and Zn effects against Cd. Lack of MT correlations suggests that metal concentrations may not be high enough to reach an MT induction threshold and that MT variability is probably linked to environmental metal concentrations. Therefore, the increased environmental contaminant levels observed in the study area indicate the need for biomonitoring efforts aiming at the application of efficient mitigation measures.

Intraspecific variation of trace elements in the kelp gull (Larus dominicanus): influence of age, sex and location

Hepatic tissue of Larus dominicanus sampled on the coastline of the state of Santa Catarina in Brazil between October 2016 and May 2018 was used to evaluate intraspecific trends and spatial distribution of essential trace elements (Mn, Co, Cu, Zn, Mo and Cr) and non-essential trace elements (As, Pb, Cd, Hg, Ba and V). Principal Component Analysis (PCA) indicated differences in the bioaccumulation of trace elements between female adults and male adults, differences to sex and age were indicated by Kruskal-Wallis test. Heat maps suggest hot spots in locals with high concentration of trace elements in liver of Larus dominicanus. In general, the concentration of trace elements were comparable with values reported in other studies carried out for this species in South America and other regions of the world. The heat maps showed to be a promising tool to identify influences of the locality on bioaccumulation of trace elements in Larus dominicanus.

Mercury Exposure in Birds Linked to Marine Ecosystems in the Western Mediterranean

Mercury (Hg), particularly as methylmercury (MeHg), is a nonessential, persistent, and bioaccumulative toxic element with high biomagnification capacity and is considered a threat to marine environments. We evaluated total Hg concentrations in liver, kidney, and brain in 62 individuals of 9 bird species linked to marine ecosystems from western Mediterranean admitted in a Wildlife Rehabilitation Center (WRC) (Alicante, Spain, 2005-2020). Age- and sex-related differences in Hg levels, as well as the cause of admission to the WRC, were also evaluated in certain species. The species studied were: northern gannet (Morus bassanus), European shag (Phalacrocorax aristotelis), great cormorant (Phalacrocorax carbo), osprey (Pandion haliaetus), Balearic shearwater (Puffinus mauretanicus), yellow-legged gull (Larus michahellis), razorbill (Alca torda), common tern (Sterna hirundo), and black-headed gull (Chroicocephalus ridibundus). Concentrations in feathers of 27 individuals, and concentrations in internal tissues in 7 other individuals of 7 different species were also reported but not statistically evaluated due to the limited number of samples. Results suggest that individuals were chronically exposed to Hg through diet. The differences in Hg concentrations among species may be explained by their diet habits. Mercury concentrations strongly correlated between tissues (r = 0.78-0.94, p < 0.001, n = 61-62). Some individuals of certain species (i.e., European shag, northern gannet, and great cormorant) showed Hg concentrations close to or above those described in the literature as causing reproductive alterations in other avian species. Consequently, certain individuals inhabiting western Mediterranean could be at risk of suffering long-term, Hg-related effects. Some of the species evaluated are listed within different categories of threat according to the International Union for Conservation of Nature (IUCN) and are endangered at a national level, so this study will provide valuable information for assessors and authorities in charge of the management of the environment and pollution.

Hepatic Metal and Metallothionein Levels in a Potential Sentinel Teleost, Dulesauriga, from a Southeastern Brazilian Estuary

The identification of estuarine sentinel species is of paramount importance. The potential of the species Dules auriga sampled from Guanabara Bay, Brazil regarding metal contamination was assessed. Hepatic metallothionein (MT) and Fe, Zn, Cu, Mn, Cd and Ag concentrations were determined in cytosolic fractions (S50 and HT S50) by polarography and ICP-OES, respectively. HT S50 Fe, Mn and Zn were lower than in the S50 fraction, indicating MT-detoxification. MT was correlated to HT S50 Zn, indicating Zn homeostasis. Zn was negatively correlated to weight (TW) and length (TL), suggesting environmental Zn influence. A moderate negative correlation between HT S50 Cu and the condition factor (CF) was observed, indicating that increasing environmental Cu concentrations may decrease D. auriga CF. Several inter-elemental correlations were observed. No MT, TW and TL correlations were found. Thus, MT variability is probably linked to environmental metal concentrations. D. auriga fulfills most sentinel requisites, and MT may be an adequate metal contamination biomarker in this species.

Subcellular metal distributions and metallothionein associations in rough-toothed dolphins (Steno bredanensis) from Southeastern Brazil

Metals are subject to internal subcellular compartmentalization, altering their bioavailability. Thus, subcellular metal assessments are crucial in biomonitoring efforts. Metal distribution in three subcellular fractions (insoluble - ISF, thermolabile - TLF and thermostable - TSF) were determined by ICP-MS in Steno bredanensis specimens from Southeastern Brazil. Associations between metals, metallothionein (MT) and reduced glutathione (GSH) were also investigated. Differential metal-detoxification mechanisms were observed. MT detoxification was mostly noted for As, Cd, and Pb, while Cu, Cr, Hg, Ni, Se and Ti displayed lower MT-associations. Fe, Zn and Se, on the other hand, were poorly associated to MT, and mostly present in the ISF, indicating low bioavailability. This is the first report on subcellular Sn and Ti distribution in cetaceans and the first in this species in Brazil. Potential protective roles of essential metals against toxic elements are postulated. This study indicates that important biochemical detoxification information is obtained through subcellular fraction analyses in marine mammals.

Methylmercury and total mercury content in soft tissues of two bird species wintering in the Baltic Sea near Gdansk, Poland

Of the various forms of Hg occurring in nature, (mono) methylmercury (MeHg) is an especially toxic form and practically all forms of Hg can be converted into MeHg as a result of natural processes. Total mercury (THg) and MeHg were determined in tissues of two piscivorous birds: razorbill Alca torda and black-throated loon Gavia arctica to provide baseline data on current mercury concentrations for liver, kidneys and pectoral muscle mercury concentrations of birds which winter on the south Baltic Sea coast. Intra and inter-specific comparisons were carried out. The study is conducted between winter and autumn and the distributions of mercury in tissues were compared with data in other studies. The following paper contains discussion of the results based on the statistical analysis and ecology aspect. The highest average Hg content was in the liver (loon ≈ 3.86 mg kg^-1 dw; razorbill ≈ 1.57 mg kg^-1 dw), then in the kidneys (loon ≈ 3.14 mg kg^-1 dw; razorbill ≈ 1.53 mg kg^-1 dw) and the lowest concentrations were in pectoral muscles (loon ≈ 1.97 mg kg^-1 dw; razorbill ≈ 0.67 mg kg^-1 dw).

Humboldt penguins' feathers as bioindicators of metal exposure

Avian feathers have the potential to accumulate trace elements originating from contaminated food and polluted environments. In fact, in feathers, metals bind to keratin, a sulphur-containing protein for which several metals have a strong affinity. Here, the concentrations of 18 essential and non-essential elements were investigated in a Humboldt penguin (Spheniscus humboldti) colony housed at the Acquario di Cattolica (Italy). This species is listed as vulnerable in the Red List of the International Union for Conservation of Nature. According to the literature, there is usually a link between metal levels in the diet of birds and levels detected in their feathers. Thus, metals were also determined in the penguins' food (capelin, Mallotus villosus). We hypothesize that the controlled conditions in which birds are kept in captivity, and the homogeneous diet that they follow could allow a better understanding of metal bioaccumulation (such as mercury) or bio-dilution (such as arsenic) in the marine food chain, indicated by penguins' feathers. Moreover, comparisons with our previous investigations performed on an ex-situ African penguin (Spheniscus demersus) colony suggest that penguins living indoors have lower body burden of metals than those living outdoors. Indeed, environmental contaminants usually found in areas subjected to anthropogenic impact, where zoos and aquaria are often located, are not accumulated to levels of concern.

Biliary and hepatic metallothionein, metals and trace elements in environmentally exposed neotropical cichlids Geophagus brasiliensis

One of the metal detoxifying mechanisms that occurs in fish is metallothionein (MT) induction and metal binding. Hepatic MT induction has been well described, but biliary MT metal detoxification has only recently been described in fish. In this scenario, metal-metal interactions have been increasingly evaluated to further understand the behavior of these contaminants regarding homeostasis and biological functions, as well as their toxic effects. Studies, however, have been mainly conducted concerning the elemental pair Se-Hg, and scarce reports are available concerning other metal pairs. Therefore, this study aimed to evaluate biliary and hepatic MT metal detoxification mechanisms in a territorial neotropical cichlid, Geophagus brasiliensis. Fish were sampled from the anthropogenically impacted estuarine Rodrigo de Freitas Lagoon, located in Southern Rio de Janeiro, and trace elements and MT were determined by inductively coupled plasma mass spectrometry (ICP-MS) and UV-Vis spectrophotometry, respectively, in fish liver and bile. MT in bile were significantly lower than in liver. Significant differences between bile and liver were observed for many trace elements, and, although most were higher in liver, Cd and Ni were significantly higher in bile, indicating efficient excretion from the body via the biliary route. A significant correlation was observed between MT and Fe in bile, and between MT in liver and Cu and Zn in bile. Molar ratio calculations demonstrated protective elements effects against Al, As, Cd, Hg, Pb and V in both bile and liver, as well as some novel interrelationships, indicating the importance of these investigations regarding the elucidation of element detoxifying mechanisms. Furthermore, investigation of other elemental associations may aid in decision-making processes regarding environmental contamination scenarios linked to public health.

Assessment of the exposure to heavy metals and arsenic in captive and free-living black kites (Milvus migrans) nesting in Portugal

Due to their high trophic level, raptor species may serve as important indicators of environmental contamination by heavy metals. This study was conducted to determine if the habitat of the black kite (Milvus migrans) is contaminated by heavy metals and arsenic and to assess the degree and type of exposure that may be present. For this purpose, this study was conducted on a group of captive birds (n = 12) and on a group of free-living birds admitted to two wildlife rehabilitation centers (n = 31). Blood samples were taken for analysis of arsenic (As), mercury (Hg) and lead (Pb) concentrations by inductively coupled plasma mass spectrometry (ICP-MS). Captive birds had the lowest blood concentrations for all toxic elements examined, but significant differences from the concentrations found in free-living birds were only observed for Hg and Pb (p < 0.01). Arsenic concentrations were almost three times higher in free-living birds (4.521 ± 5.695 µg/dl) then in captive birds (1.566 ± 0.753 µg/dl). In all the samples of captive birds' mercury was not detected, while in free-living birds we observed a concentration of 7.493 ± 8.464 µg/dl (p < 0.01). Regarding lead, we observed a concentration almost four-fold higher in free-living birds (19.430 ± 29.294 µg/dl) then in captive birds (4.449 ± 1.987 µg/dl) (p < 0.01). Therefore, available sources of Pb and Hg seem to be present in the habitat of the black kite.

Mercury in the feathers of bird scavengers from two areas of Patagonia (Argentina) under the influence of different anthropogenic activities: a preliminary study

Mercury (Hg) is a global pollutant that bioaccumulates and biomagnifies in food chains and is associated with adverse effects in both humans and wildlife. We used feather samples from bird scavengers to evaluate Hg concentrations in two different areas of Northern Patagonia. Hg concentrations were analyzed in feathers obtained from turkey vultures (Cathartes aura), Black Vultures (Coragyps atratus), and southern crested caracaras (Caracara plancus) from the two areas of Northern Patagonia (Argentina): Bariloche and El Valle. Hg was detected in all the samples analyzed, but the concentrations can be considered low for the three species in both sampling areas. The mean concentration of Hg in Bariloche was 0.22 ± 0.16 mg/kg dry weight (d.w.) in black vulture, 0.13 ± 0.06 mg/kg d.w. in turkey vulture, and 0.13 ± 0.09 mg/kg d.w. in southern crested caracara; in El Valle, the mean concentration of Hg was 1.02 ± 0.89 mg/kg d.w. in black vulture, 0.53 ± 0.82 mg/kg d.w. in turkey vulture, and 0.54 ± 0.74 mg/kg d.w. in southern crested caracara. Hg concentrations in feathers were explained by the sampling area but not by the species. The concentrations of Hg contamination were comparable to those obtained in other studies of terrestrial raptors and aquatic bioindicator raptors. The species of the present study occur throughout much of North and South America. Thus, they may be appropriate bioindicators across the species' range, which is particularly useful as a surrogate, especially in distribution areas shared with endangered scavengers such as the California condor (Gymnopsys californianus) and the Andean Condor (Vultur gryphus).

Metals in Feathers of African Penguins (Spheniscus demersus): Considerations for the Welfare and Management of Seabirds Under Human Care

Bird feathers have been proven to be reliable indicators of metal exposure originating from contaminated food and polluted environments. The concentrations of 15 essential and non-essential metals were investigated in African penguins (Spheniscus demersus) feathers from a Northwestern Italian zoological facility. These birds are exclusively fed with herring from the northeast Atlantic Ocean. Certain elements, such as Hg and Cd, reflected the bioaccumulation phenomena that occur through the marine food chain. The levels of Cr, Mn, and Ni were comparable to those registered in feathers of birds living in polluted areas. These results are important for comparative studies regarding the health, nutrition and welfare of endangered seabirds kept under human care.

Experimental manipulation of dietary arsenic levels in great tit nestlings: Accumulation pattern and effects on growth, survival and plasma biochemistry

Arsenic (As) is a ubiquitous metalloid classified as one of the most hazardous substances, but information about its exposure and effects in free-living passerines is lacking. The aim of this study is to elucidate the effect of an As manipulation experiment on survival, growth and physiology of great tits (Parus major). Wild P. major nestlings inhabiting an unpolluted area were dosed with water, 0.2 or 1 μg g^-1 d^-1 of sodium arsenite (Control, Low and High As groups), whereas those living in a metal-polluted area were dosed with water (Smelter group). Birds accumulated As in tissues (liver, bone and feathers) in a dose-dependent way. Nestlings exposed to 1 μg g^-1 d^-1 of sodium arsenite showed reduced number of fledglings per successful nest, and those exposed to 0.2 μg g^-1 d^-1 had reduced wing growth, which could have post-fledging consequences such as increased predation risk. These results suggest that the LOAEL for effects on nestling survival and development in great tits is likely equal to or below 1 μg g^-1 d^-1. However, limited effects on the biochemical parameters evaluated were found. It has been shown that As may produce oxidative stress and tissue damage, so further research exploring this issue will be carried out in a future study.

A Global Overview of Exposure Levels and Biological Effects of Trace Elements in Penguins

Trace elements are chemical contaminants that can be present almost anywhere on the planet. The study of trace elements in biotic matrices is a topic of great relevance for the implications that it can have on wildlife and human health. Penguins are very useful, since they live exclusively in the Southern Hemisphere and represent about 90% of the biomass of birds of the Southern Ocean. The levels of trace elements (dry weight) in different biotic matrices of penguins were reviewed here. Maps of trace element records in penguins were included. Data on exposure and effects of trace elements in penguins were collected from the literature. The most reported trace elements in penguins are aluminum, arsenic, cadmium, lead, mercury, copper, zinc, and manganese. Trace elements have been measured in 11 of the 18 species of penguins. The most studied biotic matrices are feathers and excreta. Most of the studies have been performed in Antarctica and subantarctic Islands. Little is known about the interaction among metals, which could provide better knowledge about certain mechanisms of detoxification in penguins. Future studies of trace elements in penguins must incorporate other metals such as vanadium, cobalt, nickel, and chromium. Data of metals in the species such as Eudyptes pachyrhynchus, Eudyptes moseleyi, Eudyptes sclateri, Eudyptes robustus, Eudyptes schlegeli, Spheniscus demersus, Spheniscus mendiculus, and Megadyptes antipodes are urged. It is important to correlate levels of metals in different biotic matrices with the effects on different species and in different geographic locations.

Trace elements in loggerhead turtles (Caretta caretta) stranded in mainland Portugal: Bioaccumulation and tissue distribution

Pollution is among the most significant threats that endanger sea turtles worldwide. Waters off the Portuguese mainland are acknowledged as important feeding grounds for juvenile loggerheads. However, there is no data on trace element concentrations in marine turtles occurring in these waters. We present the first assessment of trace element concentrations in loggerhead turtles (Caretta caretta) occurring off the coast of mainland Portugal. Also, we compare our results with those from other areas and discuss parameters that may affect element concentrations. Trace element concentrations (As, Cd, Cu, Pb, Mn, Hg, Ni, Se, Zn) were determined in kidney, liver and muscle samples from 38 loggerheads stranded between 2011 and 2013. As was the only element with higher concentrations in muscle (14.78 μg g^-1 ww) than in liver or kidney. Considering non-essential elements, Cd presented the highest concentrations in kidney (34.67 μg g^-1) and liver (5.03 μg g^-1). Only a weak positive link was found between renal Cd and turtle size. Inter-elemental correlations were observed in both liver and kidney tissues. Hepatic Hg values (0.30 ± 0.03 μg g^-1) were higher than values reported in loggerheads in the Canary Islands but lower than in Mediterranean loggerheads. Cd concentrations in the present study were only exceeded by values found in turtles from the Pacific. Although many endogenous and exogenous parameters related with complex life cycle changes and wide geographic range may influence trace element accumulation, the concentrations of Cd are probably related to the importance of crustaceans in loggerhead diet in the Portuguese coast.

Persistent organic pollutants and inorganic elements in the Balearic shearwater Puffinus mauretanicus wintering off Portugal

This study presents the first data on trace element and organic pollutant concentrations in the Critically Endangered Balearic shearwater Puffinus mauretanicus collected in 2010 and 2011 in Portugal. Trace element levels were below the threshold levels for adverse effects on birds, despite the Hg concentrations in feathers (4.35μg·g-1ww). No significant differences were detected between individuals from 2010 and 2011 except for Se concentrations in liver, feathers and muscle (higher in 2010) and Ag in liver and muscle (higher in 2011). No significant differences were detected in total concentrations of organochlorine compounds in Balearic shearwaters between years, although PCB congeners -101 and -180 presented higher concentrations in individuals from 2010. The PCB congeners -138, -153 and -180, and 4.4-DDE were detected in all individuals. This study on toxic elements and organic pollutants in wintering Balearic shearwaters provides baseline data from which deviations can be detected in the future.

Mercury in wintering seabirds, an aggravating factor to winter wrecks?

Every year, thousands of seabirds are cast ashore and are found dead along the coasts of North America and Western Europe. These massive mortality events called 'winter wrecks' have generally been attributed to harsh climatic conditions and prolonged storms which affect bird energy balance and impact their body condition. Nevertheless, additional stress factors, such as contaminant body burden, could potentially cumulate to energy constraints and actively contribute to winter wrecks. However, the role played by these additional factors in seabird massive winter mortality has received little attention to date. In February/March 2014, an unprecedented seabird wreck occurred along the Atlantic French coasts during which > 43,000 seabirds were found dead. By analyzing mercury (Hg) concentrations in various tissues collected on stranded birds, we tested the hypothesis that Hg played a significant role in this mortality. More specifically, we aimed to (1) describe Hg contamination in wintering seabirds found along the French coasts in 2014, and (2) determine if Hg concentrations measured in some vital organs such as kidney and brain reached toxicity thresholds that could have led to deleterious effects and to an enhanced mortality. We found some of the highest Hg levels ever reported in Atlantic puffins, common guillemots, razorbills and kittiwakes. Measured concentrations ranged from 0.8 to 3.6 μg · g(-1) of dry weight in brain, 1.3 to 7.2 μg · g(-1) in muscle, 2.5 to 13.5 μg · g(-1) in kidney, 2.9 to 18.6 μg · g(-1) in blood and from 3.1 to 19.5 μg · g(-1) in liver. Hg concentrations in liver and brain were generally below the estimated acute toxicity levels. However, kidney concentrations were not different than those measured in the liver, and above levels associated to renal sub-lethal effects, suggesting a potential Hg poisoning. We concluded that although Hg was not directly responsible for the high observed mortality, it has been a major aggravating stress factor for emaciated birds already on the edge. Importantly, this study also demonstrated that total blood, which can be non-lethally collected in seabirds, can be used as a predictor of Hg contamination in other tissues.

Biomonitoring of heavy metals (Cd, Hg, and Pb) and metalloid (As) with the Portuguese common buzzard (Buteo buteo)

The accumulation of heavy metals in the environment may have a wide range of health effects on animals and humans. Thus, in this study, the concentrations of arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) in the blood and tissues (liver and kidney) of Portuguese common buzzards (Buteo buteo) were determined by inductively coupled plasma-mass spectrometer (ICP-MS) in order to monitor environmental pollution to these elements. In general, Hg and As were the elements which appeared in the highest and lowest concentrations, respectively. A highest percentage of non-detected concentration was found for blood Cd (94.6 %) but, in turn, it was the only metal that was detected in all kidney samples. The kidney was the analyzed sample which showed the highest concentrations of each element evaluated. Statistically, significant differences among blood, liver, and kidney samples were observed for As and Cd (P < 0.05). Cd concentrations in kidney and liver varied significantly with age: Adults showed higher hepatic and renal Cd concentrations than juveniles. Blood Pb concentration seems to show an association with the hunting season. Although raptors are at the top of the food chain and are thus potentially exposed to any biomagnification processes that may occur in a food web, the individuals evaluated in this study generally had low levels of heavy metals in blood and tissues. However, chronic exposure to these metals was verified. The results presented here lend weight to arguments in favor of continuous biomonitoring of metals and metalloids, since heavy metals may accumulate to levels that will pose a risk to both human health and the environment.

Mercury and selenium in the muscle of piscivorous common mergansers (Mergus merganser) from a selenium-deficient European country

Although the relationship between mercury (Hg) and selenium (Se) has been studied in wild birds in areas with sufficient or excessive Se levels, little is known about this relationship in areas where the supply of Se is limited. As Hg detoxification is based on the production of biologically inactive Hg-Se complexes, the aim of this study was to investigate the relationships between the concentrations of total mercury (THg), methylmercury (MeHg), inorganic mercury (InHg=THg-MeHg), percent MeHg of THg, Se and molar ratios (THg:Se, MeHg:Se, InHg:Se) in the breast muscle (n=16) of the piscivorous common mergansers (Mergus merganser) from a Se-deficient and moderately Hg-polluted area in Poland. Mergansers were divided into two groups differing in condition (A-very good condition; C-moderate condition). Concentrations of THg, MeHg and Se were determined by atomic absorption spectrometry, modified gas chromatography atomic fluorescence spectroscopy, and spectrofluorometric methods, respectively. In all studied mergansers, mean concentrations of THg, MeHg, InHg, and Se in muscle were 2.63, 1.92, 0.46, and 0.54µgg(-1)dw, respectively. THg and MeHg concentrations in the muscle of group A mergansers were greater than in group C. The ratio of THg:Se was higher in group A than in group C (2.32 vs 1.36; p<0.01), as well as the molar ratio of MeHg:Se (A vs C: 1.98 vs 1.03; p<0.05). Comparisons between mergansers from Poland and Canada showed similar THg and percent MeHg in the muscle, but mergansers from Poland had several times lower Se levels and higher THg:Se ratios (>2.0) than the Canadian mergansers and other European and North American waterbirds. We found statistically significant positive correlations (MeHg-THg, percent MeHg/THg-MeHg, percent InHg/THg-InHg, THg:Se-THg, MeHg:Se-THg, THg:Se-MeHg, MeHg:Se-MeHg, InHg:Se-InHg, MeHg:Se-THg:Se) and some negative correlations (percent InHg/THg-MeHg, percent MeHg/THg-InHg, THg:Se-Se, MeHg:Se-Se). As THg and percent MeHg in the studied mergansers were similar to populations living in non-Se-deficient areas, it is likely that different mechanisms of muscle Hg detoxification have evolved in mergansers populations living in Se-deficient areas.

Hepatic and nephric mercury and selenium concentrations in common mergansers, Mergus merganser, from Baltic Region, Europe

The subject of the present study was the piscivorous common mergansers (Mergus merganser). The total mercury (THg), methylmercury (MeHg), selenium (Se) inorganic mercury (InHg; THg - MeHg), percentage of THg that is MeHg (%MeHg), molar ratios (THg:Se, MeHg:Se, InHg:Se), and their mutual relations in livers and kidneys were determined in ducks from an Se-deficient area in Poland. The authors verified a hypothesis that, as a result of living in an Se-deficient region, mergansers from Poland should have higher THg:Se ratios than other waterbirds with similar THg tissue levels. Although a comparison of healthy mergansers from Poland and Canada showed similar THg tissue contents, the group in the present study had a few times lower Se levels and higher THg:Se ratios (overall means >1.7 in both livers and kidneys in all studied individuals) than the Canadian group and other European and North American waterbirds. The authors found significant correlations between various relations, including MeHg-THg, InHg-THg, Se-THg, %MeHg-THg, InHg/%THg-THg, %MeHg/THg-InHg, %InHg/THg-InHg, MeHg:Se-THg:Se, InHg:Se-THg:Se, InHg:Se-MeHg:Se in liver and InHg-THg, Se-THg, Se-InHg, %MeHg-THg, %MeHg-InHg, %InHg/THg-InHg, THg:Se-THg, InHg:Se-THg, MeHg:Se-MeHg, THg:Se-InHg, InHg:Se-InHg, and InHg:Se-THg:Se in kidney. It is likely that the main factor responsible for the high value of THG:Se ratio (>1) in mergansers from Poland is Se deficiency in central and northern Europe. Therefore, this element is unlikely to participate in the detoxification of Hg in these birds.

E-waste disposal effects on the aquatic environment: Accra, Ghana

The volume of e-waste is growing around the world, and, increasingly, it is being disposed of by export from developed to developing countries. This is the situation in Ghana, and, in this paper we address the potential consequences of such e-waste disposal. Herein, we describe how e-waste is processed in Ghana, and what the fate is of e-waste-chemical contaminants during recycling and storage. Finally, to the extent it is known, we address the prospective adverse effects of e-waste-related contaminants on health and aquatic life downstream from a large e-waste disposal facility in Accra, Ghana.In developing countries, including Ghana, e-waste is routinely disassembled by unprotected workers that utilize rudimentary methods and tools. Once disassembled,e-waste components are often stored in large piles outdoors. These processing and storage methods expose workers and local residents to several heavy metals and organic chemicals that exist in e-waste components. The amount of e-waste dumped in Ghana is increasing annually by about 20,000 t. The local aquatic environment is at a potential high risk, because the piles of e-waste components stored outside are routinely drenched or flooded by rainfall, producing run-off from storage sites to local waterways. Both water and sediment samples show that e-waste-related contaminant shave entered Ghana's water ways.The extent of pollution produced in key water bodies of Ghana (Odaw River and the Korle Lagoon) underscores the need for aquatic risk assessments of the many contaminants released during e-waste processing. Notwithstanding the fact that pollutants from other sources reach the water bodies, it is clear that these water bodies are also heavily impacted by contaminants that are found in e-waste. Our concern is that such exposures have limited and will continue to limit the diversity of aquatic organisms.There have also been changes in the abundance and biomass of surviving species and changes in food chains. Therefore, the need for actions to be taken to reduce entry of e-waste pollutants into Ghana's aquatic environment is real and is immediate.Heavy metals (e.g., lead, cadmium, copper and zinc) and organic pollutants (e.g.,PCDD/Fs and PBDEs) have been detected in the sediments of local water bodies in quantities that greatly exceed background levels. This fact alone suggests that aquatic organisms that live in the affected water bodies are highly exposed to these toxic, bio-accumulative, and persistent contaminants. These contaminants have been confirmed to result from the primitive methods used to recycle and process e-waste within the local environment.Only limited local data exist on the threats posed by these e-waste-related contaminants on nearby natural resources, especially aquatic organisms. In this review,we have addressed the potential toxicity of selected heavy metals and organic pollutants on aquatic organisms. Since there are no data on concentrations of contaminants in the water column, we have based our predictions of effects on pollutant release rates from sediments. Pollutants that are attached to sediments are routinely released into the water column from diffusion and advection, the rate of which depends on pH and Eh of the sediments. E-waste contaminants have the potential to produce deleterious effects on the behavior, physiology, metabolism, reproduction,development and growth of many aquatic organisms. Because it is confirmed that both heavy metal and organic contaminants are reaching the biota of Ghana's local waterways, we presume that they are producing adverse effects. Because local data on the aquatic toxicity of these contaminants are as yet unavailable, we strongly recommend that future research be undertaken to examine, on a large scale and long-term basis, both contamination levels in biota, and adverse effects on biota of the nearby water bodies.

Distribution of metals and trace elements in adult and juvenile penguins from the Antarctic Peninsula area

The presence of metals in the Antarctic environment is principally a natural phenomenon caused by geochemical characteristics of the region, although some anthropogenic activities can increase these natural levels. Antarctic penguins present several of the characteristics of useful sentinels of pollution in Antarctica such as they are long-lived species situated at the top of food web. The concentrations of Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Cd, and Pb were determined by inductively coupled plasma-mass spectrometry in samples of liver, kidney, muscle, bone, feather, and stomach contents of gentoo, chinstrap, and Adélie penguin (12 adults, five juveniles) from carcasses of naturally dead individuals collected opportunistically in the Antarctic Peninsula area. The obtained results showed that accumulation and magnification of several elements can be occurring, so that Cd and Se reached levels potentially toxic in some specimens. The presence of human activities seems to be increasing the presence of toxic metals such as Mn, Cr, Ni, or Pb in penguins.

Monitoring trace elements in Antarctic penguin chicks from South Shetland Islands, Antarctica

The concentration of human activities in the near-shore ecosystems from the northern Antarctic Peninsula area can cause an increasing bioavailability of pollutants for the vulnerable Antarctic biota. Penguin chicks can reflect this potential impact in the rookeries during the breeding season. They also can reflect biomagnification phenomena since they are on the top of the Antarctic food chain. The concentrations of Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Cd and Pb were measured by ICP-MS in samples of liver, kidney, muscle, bone, feather and stomach content of gentoo, chinstrap and Adélie penguin chicks (n=15 individuals) collected opportunistically in the Islands of King George and Deception (South Shetland Islands, Antarctica). The detected levels of some trace elements were not as low as it could be expected in the isolated Antarctic region. Penguin chicks can be useful indicators of trace elements abundance in the study areas.

CAPSULE

Carcasses of Antarctic penguin chicks were used to evaluate the bioavailability of trace elements in the Islands of King George and Deception.

Razorbills (Alca torda) as bioindicators of mercury pollution in the southwestern Mediterranean

Levels of mercury (Hg) were analyzed in the tissues of 50 Razorbills (Alca torda), from the Mediterranean area, which had drowned in fishing nets. The mercury distribution pattern in tissues was similar to those of other studies (liver > feather vane > kidney > muscle > brain > feather shaft), with mercury concentrations of 2.85 ± 0.90, 2.66 ± 1.60, 2.23 ± 0.87, 1.54 ± 0.54, 1.48 ± 0.54 and 1.30 ± 0.76 mg/kg (dry weight), respectively. It could be considered that Razorbills in the southwestern Mediterranean were chronically exposed to relatively low levels of MeHg, probably below 0.5 ppm, via dietary intake. We have proposed prediction equations for brain and kidney Hg concentrations using feather shafts as non-invasive samples. This work provides a solid understanding of Razorbill Hg exposure both in their wintering and breeding grounds, and shows that this species can be useful for assessing marine environmental health in the Mediterranean area.

Razorbill (Alca torda) feathers as an alternative tool for evaluating exposure to organochlorine pesticides

The aim of this study was to explore the usefulness of feathers as a biomonitoring tool for organochlorine pesticides (OC) in a razorbill population (Alca torda). Fifteen OC were analyzed in feathers, including α-, β- and δ-hexachlorocyclohexane, lindane, aldrin, dieldrin, endrin, endosulfan I and II, endosulfan sulfate, p,p'-DDT, DDD, DDE, heptachlor and its epoxide. The geometric mean concentrations observed in this study were ∑DDT 67.40 ng/g, ∑HCH 62.88 ng/g, ∑Heptachlor 61.75 ng/g, ∑Endosulfan 19.70 ng/g, and ∑Drins 10.17 ng/g. The higher OC levels found in this study compared with other studies are probably affected by the razorbill diet and migration status. However, levels found in the feathers of the present study are related to concentrations in internal tissues below those which cause adverse reproductive and behavioral effects or other signs of organochlorine-pesticide poisoning in birds. Age does affect the concentration of OC pesticides in feathers. Thus, feathers would appear to be a promising tool for OC biomonitoring in seabirds, since it is possible to quantify OC compounds.

Concentration of trace elements in feathers of three Antarctic penguins: geographical and interspecific differences

Antarctica is often considered as one of the last pristine regions, but it could be affected by pollution at global and local scale. Concentrations of Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Cd and Pb were determinated by ICP-MS in feathers (n = 207 individuals) of gentoo, chinstrap and Adélie penguin collected in 8 locations throughout the Antarctic Peninsula (2006-2007). The highest levels of several elements were found in samples from King George Island (8.08, 20.29 and 1.76 μg g(-1) dw for Cr, Cu and Pb, respectively) and Deception Island (203.13, 3.26 and 164.26 μg g(-1) dw for Al, Mn and Fe, respectively), where probably human activities and large-scale transport of pollutants contribute to increase metal levels. Concentrations of Cr, Mn, Cu, Se or Pb, which are similar to others found in different regions of the world, show that some areas in Antarctica are not utterly pristine.

Analyzing trophic transfer of heavy metals for food webs in the newly-formed wetlands of the Yellow River Delta, China

Nine heavy metals sampled from water, sediments, and aquatic organisms in the newly-formed wetlands of the Yellow River Delta (YRD) of China were analyzed to evaluate their concentrations and trophic transfer in food webs. The stable carbon (δ13C) and nitrogen (δ15N) isotopes were used to investigate trophic interactions. Results show that most of heavy metals detected in water and sediments are lower than that in Yangtze River Delta and Pearl River Delta. The longest food web is approximately 4 with the highest trophic level of birds. The difference of heavy metal concentrations between endangered Saunders's Gull and other three kinds of protected birds is not obvious. Cd, Zn, and Hg were identified to have an increase with the trophic level (TL), while As, Cr, Cu, Mn, Ni and Pb show an opposite trend, however, the biomagnification of the selected nine heavy metals in the food webs is not significant.

Organochlorines and mercury in livers of great cormorants (Phalacrocorax carbo sinensis) wintering in northeastern Mediterranean wetlands in relation to area, bird age, and gender

Wild birds are exposed to pollutants in their habitats. Top consumers of aquatic environments such as the fish-eating great cormorant (Phalacrocorax carbo sinensis) are especially affected due to the bioaccumulation of toxic substances in their tissues. This study analysed the livers of 80 great cormorants from Greece to estimate the concentration of organochlorines and mercury and to examine their possible toxic effects and origin. The results showed that mercury (geometric mean 8089 ng g⁻¹ dw), p,p'-DDE (2628 ng g⁻¹ dw), ∑HCHs (47 ng g⁻¹ dw) and HCB (116 ng g⁻¹ dw) concentrations can be considered high compared with those found in great cormorant livers elsewhere except in highly polluted areas, whereas ∑PCBs occurred in relatively low concentrations (1091 ng g⁻¹ dw). β-HCH was the dominant HCH isomer. Pollutant levels were generally unrelated to area, age and gender. However, p,p'-DDE and p,p'-DDD showed intersite differences, whilst the proportion of PCBs with 8 chlorine atoms were significantly higher in adult than 1st year great cormorants. Pollution did not reflect local patterns but rather these along the Baltic and Black Seas, whilst differences in p,p'-DDE concentration and ∑DDTs/∑PCBs ratios between Evros, Axios or Amvrakikos, found on common migration route, suggested different bird origins. Most birds had toxic mercury concentrations; 83.7% above 4000 ng g⁻¹ dw and 16% above 17,000 ng g⁻¹ dw. Other pollutant levels were too low to have adverse effects.

Assessment of organochlorine pesticide exposure in a wintering population of razorbills (Alca torda) from the southwestern Mediterranean

Sixteen organochlorine pesticides (OC) were analyzed in several tissue types (abdominal and subcutaneous fat, liver and brain) from juvenile (n=14), immature (n=9), subadult (n=7) and adult (n=20) razorbill (Alca torda) collected from the southwestern Mediterranean coastline, in the East of Spain (La Marina, Elche, Alicante, Spain). These razorbills had drowned in fishing nets (most probably) while searching for food. The objective was to assess the exposure to organochlorine pesticide residues in this wintering population of marine birds. This paper presents, as far as we are aware, the first published data on OC concentrations in razorbills. The highest levels were found in abdominal fat followed by subcutaneous fat, liver and brain. A significant positive relationship was found between age and OC levels in tissues, and with the highest levels in adults. The group of sigma Drins had the highest concentrations, followed by sigma DDT, sigma Endosulfan, sigma HCH and sigma Heptachlor, with endrin aldehyde being the compound which reached the highest levels. The p,p'-DDE/p,p'-DDT ratio in fatty tissues suggests exposure to non-degraded DDT and thus is present in the environment despite its prohibition. The OC levels detected were higher than those found in other studies on Alcidae, which may be explained by the Mediterranean habitat in which the birds were found. However, these levels are below concentrations for which any observable effect has been described.

Trace element concentrations in Raillietina micracantha in comparison to its definitive host, the feral pigeon Columba livia in Santa Cruz de Tenerife (Canary Archipelago, Spain)

The use of systems involving bird parasites as bioindicators of environmental pollution has been scarcely studied in comparison to other models involving fish and rodent parasites, which have been demonstrated as particularly adequate due to their bioaccumulation capacities. The present study evaluated the accumulation of nine trace elements in the cestode Raillietina micracantha and in its host Columba livia collected from the densely populated city of Santa Cruz de Tenerife (Canary Islands, Spain). Samples (kidney, liver, pectoral muscle, feathers, and R. micracantha) of 27 infected C. livia were selected for trace element analysis by inductively coupled plasma-mass spectrometry. Element levels in pigeon tissues revealed some degree of pollution in Santa Cruz de Tenerife, particularly by Pb and Zn. Pb and Mn mean concentrations were higher in R. micracantha than in the pigeon's soft tissues, with subsequent high bioaccumulation factors for Pb (kidney = 15.38, liver = 10.38, muscle = 79.83) and Mn (kidney = 6.81, liver = 7.52, muscle = 19.89, feathers = 6.11), among others. The negative relations detected for As concentrations between liver and R. micracantha emphasize a possible role of the cestode in As detoxification in host tissues. Considering the obtained bioaccumulation factors, the system R. micracantha/C. livia is proposed as another promising bioindicator system to evaluate environmental toxic element exposure, particularly Pb and Mn, in areas where pollution levels are still relatively low and where both common species are present.