Heavy metal (Cd, Pb, Zn) and metalloid (As) content in raptor species from Galicia (NW Spain)

Distribution and biotransfer of potentially toxic elements in a terrestrial ecosystem from an abandoned realgar mine

The present study was conducted to examine the trophic transfer of potentially toxic elements (PTEs) in a closed arsenic mine. Eight PTEs in a soil-plant-leaf litter-earthworm-top predators (free-range local chicken and wild passerine bird) system were analyzed for nitrogen and carbon stable isotopes, PTE concentrations, bioaccumulation factors (BAFs), and transfer factors (TFs). The PTE concentrations in soils from mining areas were generally higher than a adjacent controlled area, with As and Cd in soils showing the prominent compared to other six PTEs, as seen for the indices of geo-accumulation index (Igeo), pollution index (PI) and potential ecological risk index (RI). The relatively high BAF and TF values suggested a distinct biotransfer of PTEs along the soil-plant-leaf litter-earthworm system. BAFs were mostly <1 except in earthworms, indicating that earthworms had a strong capacity to take up these metals. The TFs varied both among PTEs and organism's species, e.g., the transfer capacities of As in Pteris vittata and Pteris cretica, Cd in Miscanthus sinensis, and Pb, Cr and Mn in moss were the highest. For local free-range chicken and wild passerine bird, the concentrations of PTEs were higher in gastric contents and feather than in internal tissue (stomach, liver and heart), with lower contents in muscle and egg. Bioaccumulation of PTEs generally decreased from decomposer earthworms, to primary producer plants, to top predator, indicating a potential bio-dilution tendency in higher trophic levels in the terrestrial food chain.

Pellets of apex predators for monitoring metals and metalloids contamination in farmlands

Using fertilizers and plant protection products in agriculture is a primary source of metal and metalloid contamination in agricultural landscapes. Monitoring of these areas is especially crucial for the production of healthy food. In this paper, we analyzed the occurrence of trace elements commonly considered as indicators of environmental pollution in the pellets of the apex predator of farmland, representing the group of birds of prey whose pellets have not been studied in this respect so far. We used 60 pellets of the Eurasian Kestrel (Falco tinnunculus) from 20 sites, to investigate the pollutants present in the extensive agricultural landscape of eastern Poland. Further, we developed a strategy for homogenizing and digestion of the samples and proposed the sample preparation protocol of them. We determined the optimal working conditions for using inductively coupled plasma mass spectrometry (ICP-MS) to measure the content of elements identified as environmental pollutants, such as As, Cd, Cr, Cu, Mn, Ni, Pb, Se, and Zn. The obtained level of the investigated elements indicates low pollution of the farmland in eastern Poland by Cd, Cr, Ni, Pb, Se, and Zn and slightly elevated concentrations of Cu and Mn resulting from using artificial fertilizers and plant protection products. This study has shown that bird pellet analysis is a practical, non-invasive tool for studying the pollution of the environment with chemical elements. Studying bird pellets in the context of farmland contamination provides insights into the level of environmental pollution and the potential impact of agricultural activities on ecosystems.

Cadmium in Selected Organs of Game Animals from Areas with Different Degrees of Industrialisation and Its Intake by Human Consumers

The aim of this study was to determine the concentration of cadmium (Cd) in the organs of game animals from areas with different degrees of industrialisation and to assess its intake following the consumption of the livers of these animals. The material for this study consisted of liver and kidney samples taken from roe deer (Capreolus capreolus), red deer (Cervus elaphus), and wild boar (Sus scrofa) from five regions differing in land use and industrialisation. Compared to the kidneys, the liver was an indicator of the current state of the environment and Cd intake, while the kidney was used to assess the long-term accumulation of Cd in the body. The cadmium concentration in the samples was determined by inductively coupled plasma atomic emission spectrometry. The cadmium concentrations of the organs were found to vary according to geographical location, with the highest levels being observed in Southern Poland, i.e., areas characterised by the highest degree of industrialisation and the presence of heavy industry. However, high Cd concentrations were also reported in the northeastern region. Examples of excessive cadmium levels in the kidneys were noted in all tested regions. Cd intake by humans was evaluated by calculating the estimated daily cadmium intake, and this was compared with the tolerable weekly intake (TWI). The TWI was only exceeded by children frequently consuming wild boar liver from the southwest region.

Tissue distribution and correlations of heavy metals in wild birds from Southern Turkey: an ecologically important region on the west Palearctic migration route

Even if some are essential for biological functions, the accumulation of heavy metals above tolerable physiological limits is potentially toxic to also wild animals. The present study aimed to investigate concentrations of environmentally relevant heavy metals (As, Cd, Cu, Fe, Hg, Mn, Pb, and Zn) in feathers, muscle, heart, kidney, and liver tissues of wild birds (golden eagle [Aquila chrysaetos], sparrowhawk [Accipiter nisus], and white stork [Ciconia ciconia]) from Hatay province, southern Turkey. The metal concentrations of tissues were determined by a validated ICP-OES analysis method after microwave digestion. The concentration differences of metals in species/tissues and the correlations between essential/non-essential metals were determined by statistical analysis. According to the results, Fe (326.87±3.60 mg kg^-1) had the highest, and Hg (0.09±0.00 mg kg^-1) had the lowest mean concentration in all tissues. Compared to the literature; Cu, Hg, Pb, and Zn concentrations were lower; Cd, Fe, and Mn concentrations were higher. The correlations between As and all essentials; Cd and Cu, Fe; Hg and Cu, Fe, Zn; Pb and all essentials were significantly positive. In the conclusion, while essential Cu, Fe, and Zn are below the threshold value and do not pose a risk, Mn is close to the threshold value. Therefore, periodically monitoring the pollutant concentrations in bioindicators is a key necessity for the early determination of biomagnification trends and prevention of potential toxic stress on wildlife ecology.

The importance of in-year seasonal fluctuations for biomonitoring of apex predators: A case study of 14 essential and non-essential elements in the liver of the common buzzard (Buteobuteo) in the United Kingdom

Trace elements are chemical contaminants spread in the environment by anthropogenic activities and threaten wildlife and human health. Many studies have investigated this contamination in apex raptors as sentinel birds. However, there is limited data for long-term biomonitoring of multiple trace elements in raptors. In the present study, we measured the concentrations of 14 essential and non-essential trace elements in the livers of the common buzzard (Buteo buteo) collected in the United Kingdom from 2001 to 2019 and investigated whether concentrations have changed during this period. In addition, we estimated the importance of selected variables for modelling element accumulations in tissues. Except for cadmium, hepatic concentrations of harmful elements in most buzzards were lower than the biological significance level of each element. Hepatic concentrations of certain elements, including lead, cadmium, and arsenic, varied markedly seasonally within years. Their peak was in late winter and trough in late summer, except copper which showed an opposite seasonal pattern. In addition, lead in the liver consistently increased over time, whereas strontium showed a decreasing trend. Hepatic concentrations of cadmium, mercury, and chromium increased with age, whereas selenium and chromium were influenced by sex. Hepatic concentrations of arsenic and chromium also differed between different regions. Overall, our samples showed a low risk of harmful effects of most elements compared to the thresholds reported in the literature. Seasonal fluctuation was an important descriptor of exposure, which might be related to the diet of the buzzard, the ecology of their prey, and human activities such as the use of lead shot for hunting. However, elucidating reasons for these observed trends needs further examination, and biomonitoring studies exploring the effects of variables such as age, sex, and seasonality are required.

Analysis of Toxic Heavy Metals in the Pellets of Owls: A Novel Approach for the Evaluation of Environmental Pollutants

Massive quantities of unadvisable synthetic pesticides are used in modern agricultural industries in order to increase productivity to convene food demands. Wild birds are an excellent bio-indicator of environmental contaminations as pesticides and heavy metals are intentionally highly hazardous pollutants. Considerably, raptorial birds (owls) attract consumers in the food chain and food web because they have wider forager and foraging grounds. In the current investigation, owl pellets were used as a viable tool and novel approach to detecting environmental contaminants. In total, 30 pellets comprising five species were collected from selected farmlands, and 11 metals (Cr, Mn, Co, Mo, Se, V, Cu, Ni, Pb, Zn, and Fe) were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). Undeniably, the Brown Fish Owl showed more metal accumulation than the Barn Owl, Spotted Owl, Indian Eagle Owl, and Mottled Wood Owl. Among the species, the levels of metals such as Manganese (Mn), Molybdenum (Mo), Vanadium (V), Copper (Cu) and Zinc (Zn) varied significantly (p < 0.05). Nonetheless, the research revealed that the agroecosystem was contaminated with heavy metals. The present outcome highlights that the management of the environment, especially the agroecosystem, must be examined with a careful assessment of contaminants, and it is a vital resource for human and other related wildlife faunal communities.

Low occurrence of multi-antimicrobial and heavy metal resistance in Salmonella enterica from wild birds in the United States

Wild birds are common reservoirs of Salmonella enterica. Wild birds carrying resistant S. enterica may pose a risk to public health as they can spread the resistant bacteria across large spatial scales within a short time. Here, we whole-genome sequenced 375 S. enterica strains from wild birds collected in 41 U.S. states during 1978-2019 to examine bacterial resistance to antibiotics and heavy metals. We found that Typhimurium was the dominant S. enterica serovar, accounting for 68.3% (256/375) of the bird isolates. Furthermore, the proportions of the isolates identified as multi-antimicrobial resistant (multi-AMR: resistant to at least three antimicrobial classes) or multi-heavy metal resistant (multi-HMR: resistant to at least three heavy metals) were both 1.87% (7/375). Interestingly, all the multi-resistant S. enterica (n = 12) were isolated from water birds or raptors; none of them was isolated from songbirds. Plasmid profiling demonstrated that 75% (9/12) of the multi-resistant strains carried resistance plasmids. Our study indicates that wild birds do not serve as important reservoirs of multi-resistant S. enterica strains. Nonetheless, continuous surveillance for bacterial resistance in wild birds is necessary because the multi-resistant isolates identified in this study also showed close genetic relatedness with those from humans and domestic animals.

Pesticide and trace element bioaccumulation in wild owls in Brazil

Owls are outstanding environmental quality bioindicators due to their position at the top of the food chain and susceptibility to pollutant accumulation. Exposure to chemical contaminants is often a risk for these animals. Moreover, studies addressing the bioaccumulation of trace elements and pesticide residues in tropical nocturnal raptor species are scarce. We analyzed the 26 organs (heart, liver, and kidney) of Tyto furcata (n=3), Megascops spp. (n=5), Pulsatrix koeniswaldiana (n=1), and Asio stygius (n=1) carcasses, collected from June 2018 to May 2019 in the Southern region of Brazil. The original vegetation consisted of areas of Araucaria forests and grassy-woody steppes with gallery forests, which were greatly modified by the introduction of agriculture. In four animals and eight organs, the pesticides abamectin, atrazine, chlorpyrifos-ethyl, and diurom were analyzed through high-performance liquid chromatography coupled with a mass detector. In six animals and eighteen organs, the trace elements cadmium, lead, chromium, and nickel were identified via atomic absorption spectrophotometry. Chlorpyrifos-ethyl was detected in the livers of the genus Megascops. Chromium was found at high concentrations in all matrices analyzed for this trace element. Moreover, P. koeniswaldiana presented lead levels indicative of high exposure. The bioaccumulation of these toxics in owls described here can impact the population levels of these species, impact on its ecological function, and consequently unbalance the ecosystem. Moreover, owls are considered bioindicators; therefore, the occurrence of bioaccumulation indirectly gives us information about the quality of the environment.

Lead contamination in raptors in Europe: A systematic review and meta-analysis

Lead contamination is a widely recognised conservation problem for raptors worldwide. There are a number of studies in individual raptor species but those data have not been systematically evaluated to understand raptor-wide lead exposure and effects at a pan-European scale. To critically assess the extent of this problem, we performed a systematic review compiling all published data on lead in raptors (1983-2019) and, through a meta-analysis, determined if there was evidence for differences in exposure across feeding traits, geographical regions, between hunting and non-hunting periods, and changes over time. We also reviewed the impact of lead on raptors and the likely main source of exposure. We examined 114 studies that were unevenly distributed in terms of time of publication and the countries in which studies were performed. Peer-reviewed articles reported data for 39 raptor species but very few species were widely monitored across Europe. Obligate (vultures) and facultative scavengers (golden eagle, common buzzard and white-tailed sea eagle) accumulated the highest lead concentrations in tissues and generally were the species most at risk of lead poisoning. We found no evidence of a spatial or decadal trend in lead residues, but we demonstrated that high lead blood levels relate to hunting season. Exposure at levels associated with both subclinical and lethal effects is common and lead from rifle bullets and shot is often the likely source of exposure. Overall, our review illustrates the high incidence and ubiquity of lead contamination in raptors in Europe. However, we did not find studies that related exposure to quantitative impacts on European raptor populations nor detailed studies on the impact of mitigation measures. Such information is urgently needed and requires a more harmonised approach to quantifying lead contamination and effects in raptors across Europe.

Dietary proxies (δ15N, δ13C) as signature of metals and arsenic exposure in birds from aquatic and terrestrial food chains

In this study, exposure to arsenic (As), lead (Pb), cadmium (Cd), copper (Cu) and zinc (Zn) was investigated in the blood, pectoral muscles and tail feathers of two terrestrial (spotted owlet; Athena brama and bank myna; Acridotheres ginginianus) and two aquatic (cattle egret; Bubulcus ibis and pond heron; Ardeola grayii) bird species inhabiting Pakistan. Food chain specimens, as well as the dietary proxies δ¹⁵N and δ¹³C, were also analyzed to validate potential trophic and dietary transfers of metals and As in birds. Zn was found to be the most prevalent metal in the tissues of birds followed by Pb, As, Cu, and Cd. The bioaccumulation of metals and As was higher in tail feathers reflecting the combined effect of both endogenous and exogenous contamination. Pectoral muscle and blood harbored lower levels of As and metals, indicating less recent exposure through diet. Aquatic birds feeding at higher trophic levels accumulated significantly higher concentrations of metals and As in their tissues (P < 0.05) and, therefore, may be at a greater risk of metal and As toxicity than terrestrial birds. Linear regression model depicts δ¹⁵N as a strong predictor of metals and As levels in the tissues of both aquatic and terrestrial birds, followed by the δ¹³C dietary proxy. All metals in aquatic species, except for Cd, as well as terrestrial species, except for Cu, exhibit bioaccumulative potential through the food chain (Trophic transfer factor: TTFs > 1) indicating potential harmful consequences for birds. Elevated concentrations of metals and As in tissues may cause harmful effects in birds potentially leading to declines in their populations.

Oxidative stress risk assessment through heavy metal and arsenic exposure in terrestrial and aquatic bird species of Pakistan

In this study, we investigated metal- and metalloid-induced oxidative stress response in two aquatic (cattle egret (Bubulcus ibis) (n = 10), pond heron (Ardeola grayii) (n = 10)), as well as two terrestrial (spotted owlet (Athene brama) (n = 6) and bank myna (Acridotheres ginginianus) (n = 16)) bird species collected from the outskirts of Lahore city, Pakistan. For this purpose, glutathione (tGSH) and lipid peroxidation (thiobarbituric acid-reactive substances (TBARS)) levels and activities of antioxidant enzymes (superoxide dismutase (SOD); catalase (CAT)) were analyzed as biomarkers of oxidative stress against metal (Pb, Cd, Cu, Zn) and metalloid (As) concentrations in kidney liver and blood of birds. Our results depicted significant correlation for Pb, Cd, and As with oxidative stress biomarkers in birds. The levels of heavy metals and As and their corresponding effects on oxidative stress biomarkers were comparably higher in aquatic species (p ≤ 0.01) except for Pb and Zn. In comparison of species, SOD and tGSH activities were higher in bank myna and cattle egret, while CAT activity and TBARS concentrations were higher in pond heron and cattle egret, respectively. We deduced that tissues with higher accumulation of metal(loid)s such as liver and kidney were under a great risk to oxidative damage. The overall order of metal accumulation and subsequent oxidative damage among families followed the pattern as Strigidae ≥Ardieda ≥ Sturnidae with their respective trophic levels. Globally, metal- and As-induced oxidative stress is least emphasized in multiple tissues of birds that is needed to be addressed with focus on case-control studies using dose-response approach. Graphical abstract .

Temporal Changes in Concentrations of Lead and Other Trace Metals in Free-Ranging Eurasian Eagle Owls Bubo bubo in Sweden

Patterns of lead and other trace metals were examined in 122 Eurasian eagle owls Bubo bubo found dead in Sweden in the period 1978-2013. Environmental lead (Pb) has decreased over recent decades from reduced anthropogenic emissions but mortality by Pb poisoning is still frequently reported for avian raptors and scavengers exposed to Pb ammunition. One objective here was to determine if Pb concentrations in a nocturnal non-scavenging raptor follow the general decline observed in other biota. Pb concentration in owl liver was significantly correlated with body weight, sex, latitude, longitude and season. Pb showed a significant decreasing trend towards north and west. Starved birds had significantly higher concentrations. Total Pb concentrations in liver averaged 0.179 μg g^-1 dry weight (median 0.103) and decreased by 5.6% per year 1978-2013, or 5.3% after adjustment for confounding factors, similar to trends in other species. Among 14 other trace elements only antimony and arsenic showed decreasing trends. Lead isotope ratios ²⁰⁶Pb/²⁰⁷Pb and ²⁰⁸Pb/²⁰⁷Pb increased from 1.138 and 2.408 in 1978-1985 to 1.170 and 2.435 in 2010-2013, respectively, demonstrating that the decreasing Pb concentration in eagle owl is related to the phase-out of leaded gasoline in Europe, where Pb additives had much lower isotope ratios than natural lead in Swedish soils. Only one incidence of suspected Pb poisoning (40.7 μg g^-1 in liver) was observed indicating that poisoning from ingestion of metallic lead is rare (< 1%) in eagle owl in Sweden, in contrast to what has been reported for eagles.

Zinc and cadmium mapping by NanoSIMS within the root apex after short-term exposure to metal contamination

Zinc as a micronutrient and cadmium as a nonessential toxic element share similar pathways for entering plant tissues and thus may be antagonistic. In nutrient solution culture, 17-day-old radish (Raphanus sativus L) plants were exposed to short-term (24 h) equimolar metal contamination (2.2 µM of each ⁷⁰Zn and total Cd) to investigate the in situ Zn/Cd distribution in the apical root tissues using high-resolution secondary ion mass spectrometry (NanoSIMS) imaging. Inductively-coupled plasma mass spectrometry analysis of bulk root tissue confirmed large root uptake of both metal elements. After 24-h exposure the total root concentration (in µg/g DW) of ⁷⁰Zn was 180 ± 24 (mean±SE) and of total Cd 352 ± 11. NanoSIMS mapping was performed on the cross sections of the radish root apex as a crucial component in root growth and uptake of water and nutrients from soil. Elemental maps of ⁷⁰Zn and ¹¹⁴Cd isotopes revealed greater enrichment of both metals in the outer epidermal root layer than in cortical tissues and especially stele, confirming the epidermal root cells as preferential sites of metal uptake, and indicating relatively slow and less-intensive metal transport into other parts (edible hypocotyl, shoot) of metal-sensitive radish. NanoSIMS has been confirmed as a powerful tool for spatial detection and visualisation of some ultra-trace metal isotopes (e.g. ⁷⁰Zn) in the fast-growing root tips. However, precise (sub)cellular mapping of diffusible metallic ions (Cd, Zn) remains a technically-challenging task in plant specimens given an unavoidable compromise between optimising methodology for structural preservation vs. authentic in vivo ion localisation.

Mercury (Hg), Lead (Pb), Cadmium (Cd), Selenium (Se), and Arsenic (As) in Liver, Kidney, and Feathers of Gulls: A Review

Mercury (Hg), lead (Pb), cadmium (Cd), selenium (Se), and arsenic (As) are metals or metalloids of high concern because of their effects on the environment and, specially, their potential toxicity on the animals inhabiting there. Due to their relevance, these elements have been object of several biomonitoring studies in different animal species around the world. Birds are widespread and, as species, are able to supply specific and relevant information about the regions where they live, being useful as bioindicators, as long as they are not birds with a strong migratory character. The main goal of this review is to summarize data collected from different studies using seabirds, paying special attention to gulls, in order to be helpful for coming studies and regulatory affairs.Several tissues have been used to evaluate Hg, Cd, Pb, Se, and As concentrations in seabirds, being focused the present review in those analyzing the liver, kidneys, and feathers. The most frequently analyzed tissue for Hg was the liver, followed by feathers, and finally kidney. For Cd levels, most of the studies were carried out in the liver, followed by feathers and kidneys. Pb, Se, and As levels were determined to a lesser extent. Feathers should be taken carefully as indicator of accumulation of pollutants, since procedure during analysis may lead to controversial results.Some authors reported that interspecific differences in the exposure of elements are determined by multiple factors, including properties of the contaminant, species, feeding habits, migratory status, sex, and age.The present review provides a comprehensive overview of the analyzed elements' occurrence in different species of seabirds, including gulls. Therefore, it can be a useful database providing for Hg, Pb, Cd, Se, and As levels in different tissues of seabirds.

Metal Concentrations in Eurasian Eagle Owl Pellets as a Function of Reproductive Variables in Korea

Eight metals were analyzed in the pellet of Eurasian eagle owls (Bubo bubo) breeding in Korea: Paju, Ganghwa, Gimpo, and Sihwa, Gyeonggi-do (N = 15, respectively). Except for cadmium (Cd), concentrations of all metals differed among sites (ANOVA, p < 0.001); Sihwa had relatively higher metal concentrations compared with other sites. Clutch size did not differ among the four sites. However, Sihwa had the greatest nesting success and number of fledglings (per hatchlings and laid egg) and highest mean weight of diet. Lead concentrations in the pellets were generally lower than the excrements of various birds worldwide. We suggest that all metal concentrations in pellets do not negatively affect the reproduction of Eurasian eagle owls, and food supply at Sihwa seems likely more important to breeding success than metal contamination.

A comparative study of inorganic elements in the blood of male and female Caspian pond turtles (Mauremys caspica) from the southern basin of the Caspian Sea

Due to their bioaccumulation and biomagnification pathways, inorganic elements can accumulate in high-level aquatic organisms in the food web. Then, this species can be used to monitor the quality of the environment. Blood concentration of nine inorganic elements, including possible toxic metals (An, Cu, Mn, Se, As, Ni, Cd, Pb, and Hg), in 20 males and 20 females from eight different locations with high industry and agriculture activities in Iran were evaluated in this work. Additionally, size, sex, condition index, and locations were also included and analyzed. Among the essential elements, Zn and Se presented very high concentrations (56.14 ± 2.66 and 8.44 ± 0.77 μg/g ww, respectively) in all locations. Regarding possible toxic elements, Pb and Cd presented concerning concentrations as well (0.52 and 0.58 μg/g ww); this is especially true for Pb, an element found in very high concentrations in tissues of turtles from the same area in a previous study. The sex and the size of the individuals also had significant differences in concentration of Pb, Cd, As, and Hg.

Concentração de elementos traços em serpentes do litoral e da região serrana do Espírito Santo

RESUMO: Os elementos químicos, em sua maioria, encontram-se em ciclos bioquímicos e geoquímicos fechados e em concentrações que não causam efeitos nocivos aos organismos. Contudo, ações antrópicas aceleradas promovem alterações ambientais, como o aumento no aporte de contaminantes. Com essas informações, o presente trabalho buscou caracterizar a presença aos elementos traços em duas espécies de serpentes comuns na região sudeste, Boa constrictor e Bothrops jararaca. Os exemplares de B. constrictor (n=18) foram provenientes de atropelamentos ocorridos no trecho da Rodovia ES-060 do Km 0 ao Km 67,5. Os exemplares de B. jararaca (n=18) foram capturados por fazendeiros na zona rural da região serrana do Espírito Santo. Foram analisados 1 grama de fragmento de rim, de espécimes necropsiados. Os rins coletados foram digeridos com mistura ácida (HNO3;HCl; 1:1) a 300oC, 40min e a quantificação de microelementos (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb e Zn) foi realizada por espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES). Não foram observadas diferenças significativas entre machos e fêmeas, exceto para Cromo nas B. constrictor (p=0,03), com média de 1,6595 nas concentrações de Cr nas fêmeas e 0,2896 em machos. Contudo, quando foram comparadas as diferentes espécies de serpentes, diferentes concentrações foram encontradas, para todos os elementos determinados, com destaque para o Ferro com uma concentração de 106,2mg/g em B. constrictor e 120,3mg/g em B. jararaca, provavelmente por esses animais virem de áreas próximas à portos de minério de ferro. A concentração de Zinco em B. constrictor foi de 1261,8mg/g e em B. jararaca foi de 28,4mg/g. O presente estudo indica que as serpentes analisadas, que habitam as regiões da Grande Vitória e serrana do Espírito Santo apresentam elevadas concentrações dos microelementos Zn e Fe.

Trace element concentrations in livers of Common Buzzards Buteo buteo from eastern Poland

In this study, our aim was to determine the common sources of origin of 18 elements in the livers of Common Buzzards collected during the breeding season in an extensive agricultural landscape in south-east Poland with respect to age (adults and immatures) and sex (males and females). In all 34 specimens collected, the element concentrations followed the pattern of S > Na > Fe > Mg > Zn > Si > Cu > Mn > Ba > Se > B > Pb > Hg > Cd > Cr > Ni > Sr > V. Among the heavy metals examined, only the concentration of Pb was relatively high. Given the prevalence of farmland in the studied area (and the wide use of fertilizers), common use of lead-hunting ammunition and moderate concentration of Pb in fertilizers, the indirect influence of hunting ammunition ingested with food or as gastroliths was apparently responsible for the elevated levels of Pb in the livers of Common Buzzards. In our study, no significant sex-related differences were detected in the hepatic concentrations of any element. However, a significant age effect was observed for three elements, which had elevated levels in adults (Hg) and immature birds (B, Pb), and a significant age x sex interaction was found for S and Fe. These results might be explained by the importance of these elements in bone growth in immature birds (B), variable strategies of foraging between adults and immature birds (Pb), and possible intersex differences in the immature cohort in response to the presence of lead (S, Fe).

Mercury, lead, and cadmium in tissues of the Caspian Pond Turtle (Mauremys caspica) from the southern basin of Caspian Sea

Concentrations of cadmium, lead, and mercury were measured in different tissues (liver, muscle, and shell) of 60 Caspian Pond Turtles collected from Tajan and Shiroud Rivers, southern basin of the Caspian Sea. Based on the results, different tissues showed different capacities for accumulating trace elements. The general trend of metals accumulation was: liver > shell > muscle. Results also showed that accumulation of these elements was not significantly different between sex and river in turtles (p > 0.05). Based on the results, Hg and Pb concentrations recorded in the present study were higher than some of the maximum concentration permissible. To our knowledge, this is the first report into heavy metal accumulation in tissues and organs of Caspian Pond Turtle from the southern basin of Caspian Sea. Further studies are needed to measure different heavy metals and trace metals in this valuable species.

Study of temporal trends in mercury concentrations in the primary flight feathers of Strix aluco

Temporal trends in Hg concentrations were determined in the primary flight feathers of 146 specimens of Strix aluco which had died in various Wildlife Recovery Centres in Galicia (NW Spain) between 1997 and 2014. The aim of the study was to determine whether standardization of a primary flight feather (or feathers) in this species is essential for identifying temporal trends in Hg concentrations. For this purpose, we had to first standardize the feather(s) analyzed to enable comparison of the levels of Hg detected in different feathers. The results show a high degree of both inter and intra-individual variability but despite that, it was possible to identify P5 as the most representative feather taking into account the amount of metal excreted in each feather and the intra-individual variability: its median was 133ng, which represents 15% (from 7% to 15%) of the total Hg present in all the primary feathers. However, this "standard feather" did not reveal any temporal trend in Hg concentrations for the study period. This lack of trend was found irrespective of the feather considered and it is expected that detection of any existing trend would also not depend on the feather considered. We conclude that use of any particular feather is not essential for identifying temporal trends in Hg concentrations, because the pattern will be identified regardless of the feather selected.

Assessment of Trace Element Concentrations in Birds of Prey in Korea

This study presents liver concentrations of trace elements of cinereous vultures (Aegypius monachus), common buzzards (Buteo buteo), common kestrels (Falco tinnunculus), and Eurasian eagle owls (Bubo bubo) collected in Korea from 2007 to 2008. Iron (Fe), manganese (Mn), copper (Cu), lead (Pb), and cadmium (Cd) concentrations in common kestrel juveniles were greater than in other juveniles of birds of prey. Adult cinereous vultures had greater Fe, Pb, and Cd concentrations than in those of other species, but common kestrels had greater Mn and Cu concentrations than in those of other birds of prey. Zinc concentrations in Eurasian eagle owl juveniles and adults were greater than in juveniles and adults of other species, respectively. In common kestrels, Fe, Cu, Pb, and Cd concentrations were significantly greater in adults than in juveniles. In Eurasian eagle owls, only Pb concentrations were greater in adults than in juveniles. Essential elements, such as Fe, Zn, Mn, and Cu concentrations, were within the range of other birds of prey studies. Seventeen individual birds of prey (30 %) were at a level considered Pb exposed (6-30 µg/g dw). This is a greater proportion than reported earlier in herons, egrets, and other birds from Korea. Elevated Pb concentration might be attributed to ingestion of Pb shot and bullet fragments for cinereous vultures and common buzzards, and urbanization for common kestrels. Cadmium concentrations in birds of prey were within the background concentrations (<3 µg/g dw) for wild birds.

Toxicity Assessment on the Levels of Select Metals in the Critically Endangered Indian White-backed Vulture, Gyps bengalensis, in India

To assess the potential contribution of metals to the catastrophic population decline of the White-backed Vulture, Gyps bengalensis, their concentrations in various organs was quantified. Liver, kidney, pectoral muscle, gut contents and femur bone were collected from dead birds between 1999 and 2008. These samples were analysed for lead, cadmium, copper and zinc, which were detected in all organs with no significant variation among tissues or between sexes. Moreover, high lead levels in liver (8.56 µg/g wet weight) and kidney (9.31 µg/g wet weight) in some individuals indicate toxic effects. Nonetheless, the levels of most metals measured in the present study may be considered as normal.

Influence of taxa, trophic level, and location on bioaccumulation of toxic metals in bird's feathers: a preliminary biomonitoring study using multiple bird species from Pakistan

Increasing concentrations of heavy metals in the environment and their effects on ecosystems and biota is still an imminent threat, particularly in developing parts of the globe. The aim of the present study was to screen the heavy metal concentrations in multiple bird species across Pakistan and to preliminary evaluate the influence of taxa, trophic level, and geographical location on heavy metal accumulation in various bird species. For this purpose, we measured the concentration of 9 heavy metals (Pb, Cd, Cr, Ni, Co, Cu, Fe, Zn and Mn) in feathers of 48 bird species from different localities in Pakistan. Species exhibited heterogeneous levels of heavy metals in feathers with marked inter and intra specific variations. Mean concentrations of studied metals in feathers followed the trend Fe>Zn>Cu>Pb>Mn>Cr>Ni>Co>Cd. Species belonging to closely related taxa (families) showed comparable metal concentrations in their feathers, inferring potential phylogenetic similarities in metal exposure or accumulation. In general, concentrations of metals were greatest in carnivorous species followed by omnivorous and insectivorous birds, and granivores showing minimal levels (p<0.000). Furthermore, concentrations of metals varied significantly between locations (p<0.000) exhibiting highest concentrations in Punjab province and Baluchistan, probably due to higher industrial and agricultural activity and runoff, respectively. With certain limitation, influence of trophic level, taxonomic affiliation and sampling location of birds on toxic metal accumulation was also statistically corroborated through principal component analysis (PCA). This study highlights that despite restricted emissions, heavy metals persist in the local environment and may pose elevated risks for the studied bird species in Pakistan.

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.

The use of feathers in monitoring bioaccumulation of metals and metalloids in the South African endangered African grass-owl (Tyto capensis)

Few studies have quantified metals in South African species and no published data on residues specifically in South African owl feathers exist. Tyto capensis is listed as vulnerable within South Africa, making it preferable to use a non-invasive technique to determine metal bioaccumulation for this species. Comparisons are made with the cosmopolitan T. alba to determine whether this species could be used as a surrogate. Concentrations of various metals were thus determined in feathers of the two species and compared with liver and muscle samples. Samples were taken from 119 owls collected as road kill along a national road. A comparison of concentrations in feathers revealed similarly higher concentrations of aluminium, antimony, lead, nickel, and strontium, whereas concentrations of chromium, copper, iron, manganese, selenium, titanium and zinc were similarly higher in internal tissues for both species. Metal concentrations of owls were comparable to those reported in literature and below toxic levels, suggesting that these metals were not likely to impact the owls. Further regressions between feathers and corresponding livers were examined to determine if feathers were indicative of internal metal burdens. Significant positive relationships were found for aluminium, copper, lead, nickel and vanadium in T. alba and nickel, manganese and vanadium in T. capensis. Preliminary results support the feasibility of using feathers as non-destructive indicators of environmental contamination in T. capensis although caution needs to be taken when interpreting the results.

Assessment of trace metals in four bird species from Korea

In birds, heavy metal concentrations are influenced by diet intake, migratory pattern, and residence time. In the present study, heavy metal concentrations (in microgram per gram dry weight) were measured in livers of four bird species from Korea. Iron concentrations were greater in Eurasian Woodcocks (Scolopax rusticola) than in Grey Herons (Ardea cinerea), Little Egrets (Egretta garzetta), and Schrenck's Bitterns (Ixobrychus eurhythmus). Copper concentrations in Grey Herons were significantly higher than in other species. Lead concentrations were greater in Schrenck's Bitterns and Eurasian Woodcocks than in Grey Herons and Little Egrets. Eurasian Woodcocks had higher cadmium concentrations than in other species. Zinc and manganese concentrations did not differ among species. Iron, zinc, manganese, and copper concentrations from this study were within the range of other Korean bird studies, and these concentrations were far below toxic levels. Cadmium and lead accumulation trends in each species were different, and the results might be associated with their migration pattern and residence time in Korea. Grey Herons, Little Egrets, and Schrenck's Bitterns are usually summer visitors, and Eurasian Woodcocks are passage migrants. But herons and egrets were collected in spring, autumn, and winter, but not during breeding season. They might be residents, so they could more reflect Korean cadmium and lead contaminations than Schrenck's Bitterns. However, Eurasian Woodcocks could more reflect habitats outside Korea because of their short staying time in Korea.

Assessment of trace elements concentrations in Western reef heron (Egretta gularis) from southern Iran

The purpose of this article was to investigate the levels of metals, cadmium, lead, and zinc, in Western reef heron (Egretta gularis) (n = 15) in order to (1) examine the sex-related variation in trace metal accumulation and (2) determine the significant differences between the metal concentrations in the kidney, liver, and pectoral muscle. Bird samples were collected from throughout the Hara biosphere reserve of southern Iran, during November and December 2010 and the concentration of metals were measured using a Shimadzu AA 680 flame atomic absorption spectrophotometer. The overall cadmium, lead and zinc concentrations means were measured as 0.8 ± 0.1, 3.4 ± 1.1, and 29.4 ± 12.9 μg/g for kidney; 0.7 ± 0.1, 2.2 ± 0.5, and 65.9 ± 20.7 μg/g for liver; and 0.2 ± 0.1, 2.2 ± 0.7, and 17.6 ± 12.9 μg/g for pectoral muscle, respectively. The results showed that with the exception of cadmium in liver, there were no significant differences between males and females (t test, p > 0.05). In the contrast, the results indicated metal concentrations differed significantly in kidneys, livers, and pectoral muscles among tissues in Western reef heron (one-way analysis of variance, p < 0.001).

Evaluation of different contour feather types for biomonitoring lead exposure in Northern goshawk (Accipiter gentilis) and tawny owl (Strix aluco)

The concentration of Pb was determined in feathers (contour feathers: mantle, pectoral, ventral, and primary- and secondary-coverts) of two sedentary species of raptors in Galicia (NW Spain): the tawny owl (Strix aluco) and the Northern goshawk (Accipiter gentilis). A high degree of intraindividual variability was observed in all types of feathers, with coefficients of variation exceeding 100 percent. The correlations between feather types were too low to enable use of a single type of body feather to predict the concentration of Pb in the other feathers. The number of body feathers required to differentiate individuals on the basis of the concentration of Pb was extremely high, in some cases higher than the number of the particular type of feather in the bird. All of this provides clear evidence that the contour and covert feathers of the raptor species considered cannot be used to biomonitor contamination by Pb, at least in this sample where the overall feather concentration were fairly uniform.

Assessment of lead exposure in Spanish imperial eagle (Aquila adalberti) from spent ammunition in central Spain

The Spanish imperial eagle (Aquila adalberti) is found only in the Iberian Peninsula and is considered one of the most threatened birds of prey in Europe. Here we analyze lead concentrations in bones (n = 84), livers (n = 15), primary feathers (n = 69), secondary feathers (n = 71) and blood feathers (n = 14) of 85 individuals collected between 1997 and 2008 in central Spain. Three birds (3.6%) had bone lead concentration > 20 μg/g and all livers were within background lead concentration. Bone lead concentrations increased with the age of the birds and were correlated with lead concentration in rachis of secondary feathers. Spatial aggregation of elevated bone lead concentration was found in some areas of Montes de Toledo. Lead concentrations in feathers were positively associated with the density of large game animals in the area where birds were found dead or injured. Discontinuous lead exposure in eagles was evidenced by differences in lead concentration in longitudinal portions of the rachis of feathers.

Use of raptors for biomonitoring of heavy metals: gender, age and tissue selection

The concentrations of cadmium, mercury and lead were determined in liver, kidney and feathers of Accipiter gentilis, Buteo buteo and Strix aluco. No significant differences in the concentrations of metals were observed in relation to either age or gender. Cadmium levels in feathers and in kidney were significantly correlated (p < 0.01 or p < 0.05) in all species. In B. buteo, cadmium concentrations in feathers and in liver were also correlated (p < 0.01), as were the concentrations of lead in feathers and in liver (p < 0.05). The low correlation coefficients let to reject the possibility of predicting metals concentrations in viscera from the concentrations in feathers.

Application of indicator kriging to the complementary use of bioindicators at three trophic levels

The use of biological indicators is widespread in environmental monitoring, although it has long been recognised that each bioindicator is generally associated with a range of potential limitations and shortcomings. To circumvent this problem, this study adopted the complementary use of bioindicators representing different trophic levels and providing different type of information, in an innovative approach to integrate knowledge and to estimate the overall health state of ecosystems. The approach is illustrated using mercury contamination in primary producers (mosses), primary consumers (domestic pigeons and red-legged partridges) and top predators (Bonelli's eagles) in southern Portugal. Indicator kriging geostatistics was used to identify the areas where mercury concentration was higher than the median for each species, and to produce an index that combines mercury contamination across trophic levels. Spatial patterns of mercury contamination were consistent across species. The combined index provided a new level of information useful in incorporating measures of overall environmental contamination into pollution studies.