Heavy metal distribution in some wild birds from Korea

Lead, cadmium, and other trace elements in the liver of golden eagles and white-tailed eagles: recent data from Poland and a systematic review of previous studies

The golden eagle (Aquila chrysaetos) and the white-tailed eagle (Haliaeetus albicilla), being apex predators and facultative scavengers, can bioaccumulate different environmental contaminants, including toxic elements that may adversely affect their health. We analyzed the levels of cadmium (Cd), lead (Pb), and other metals and metalloids, including arsenic (As), barium (Ba), beryllium (Be), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), selenium (Se), thorium (Th), thallium (Tl), uranium (U), vanadium (V), and zinc (Zn) in liver samples taken from three golden eagles and 36 white-tailed eagles that were found dead across Poland to verify their exposure. We also used a systematic review to summarize the available literature data on Cd, Pb, and other studied elements in the liver of both eagle species. Analyses of trace elements in the liver samples of the Polish eagles revealed interspecific differences in Cd, Cu, and Mn and differences in Co, Mn, Tl, and Zn among study regions. All elements tested except Pb were below the suggested thresholds linked with adverse health effects in birds. The hepatic Pb found in almost half of all the tested individuals suggests environmental exposure to this toxic element. One of the tested white-tailed eagles had hepatic Pb above the threshold of sublethal poisoning. Although our results seem optimistic, as previous Polish studies showed a higher prevalence of birds with hepatic Pb exceeding the toxicity threshold, they indicate that exposure to this toxic metal could still pose an additional threat to the health of Polish eagles.

Tissue distribution and association of heavy metal accumulation in a free-living resident passerine bird tree sparrow Passer montanus

Passerine birds have been increasingly used as effective sentinels of ecosystem contamination. They can provide direct evidence of the bioavailability and accumulation of heavy metal elements in the environment. In this study, the bioaccumulation of four heavy metals (Cu, Zn, Pb, and Cd) and Ca in different organs and tissues (feathers, internal organs, skeletons, and muscles) of an urban bird, tree sparrow (Passer montanus), collected from a polluted site [Baiyin (BY)] and a relatively unpolluted site [Liujiaxia (LJX)], and their associations were investigated. There were significantly higher and lower concentrations of heavy metals and Ca, respectively, in different organs and tissues of sparrows in BY than those in LJX. However, except for Pb, the heavy metal levels were below the threshold of sublethal effects. Age-dependent variations in metals were quantified, and it was found that adult bird contained higher concentration of different organs and tissue metals, except for feathers, compared with nestlings and juveniles. The tissue distribution of heavy metals in sparrows of different ages and sex was similar in the two study sites, and heavy metal elements were mainly accumulated in the feathers. This study further investigated the correlation between heavy metals in different organs and tissues and found that the correlations between them were strong in nestlings and adults but weak in juveniles. In addition, Pb and Cd in internal organs, skeletons, and muscles of young sparrows can be estimated using feathers, whereas Cu and Zn were found in adult sparrows. Altogether, our results suggest that tree sparrows will serve as valuable biomonitors of environmental heavy metal pollution and will underscore the importance of tissue types in avian ecotoxicology field studies.

Comparison of metal burden in different muscle tissues of Great cormorant (Phalacrocorax carbo)

Concentrations of 12 metals (As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb and Zn) were examined in the pectoral and thigh muscle of great cormorants (Phalacrocorax carbo). The samples were collected from Central Tisza-Jászság Nature Conservation Area in Hungary. The tissue samples were analysed by inductively coupled plasma optical emission spectroscopy (ICP-OES). The aim of the study was to examine the impacts of heavy metal pollution on the water birds, determine the concentrations of the abovementioned metals in the different muscle tissues of these wetland birds, and provide the basic materials for monitoring the environmental pollution. Among the investigated elements/metals, the detected concentrations of As, Ba, Cd, Co, Cr, Mo and Ni were below the detection limit. Higher concentration of Cu, Hg, Mn and Pb was measured in the pectoral muscle compared to the thigh muscle, but only in the case of Cu and Mn were found significant differences between the tissues. In the case of the Zn concentration, the higher value was detected in the thigh muscle. There were no statistical differences between males and females in either metal concentrations.

Heat shock proteins took part in oxidative stress-mediated inflammatory injury via NF-κB pathway in excess manganese-treated chicken livers

Manganese (Mn) is an essential metal in humans and animals. However, excess Mn entered environment due to the wide application of Mn in industry and agriculture, and became an environmental pollutant. Exposure to high doses of Mn is toxic to humans and animals (including chickens). Liver is a target organ of Mn poisoning. Nevertheless, there were few studies on whether Mn poisoning damages chicken livers and poisoning mechanism of Mn in chicken livers. Herein, the aim of this study was to explore if oxidative stress, heat shock proteins (HSPs), and inflammatory response were involved in the mechanism of Mn poisoning-caused damage in chicken livers. A chicken Mn poisoning model was established. One hundred and eighty chickens were randomly divided into one control group (containing 127.88 mg Mn kg^-1) and three Mn-treated groups (containing 600, 900, and 1800 mg Mn kg^-1, respectively). Histomorphological structure was observed via microstructure and ultrastructure. Spectrophotometry was used to detect total antioxidant capacity (T-AOC) and inducible nitric oxide synthase (iNOS) activity, as well as nitric oxide (NO) content. And qRT-PCR was performed to measure mRNA expression of inflammatory genes (nuclear factor kappa B (NF-κB), tumor necrosis factor α (TNF-α), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and iNOS) and heat shock protein (HSP) genes (HSP27, HSP40, HSP60, HSP70, and HSP90). Multivariate correlation analysis, principal component analysis, and cluster analysis were used to demonstrate the reliability of mechanism of Mn poisoning in our experiment. The results indicated that excess Mn led to inflammatory injury at three contents and three time points. Meanwhile, we found that NO content, iNOS activity, and NF-κB, TNF-α, COX-2, PGE2, and iNOS mRNA expression increased after Mn treatment, meaning that exposure to Mn induced inflammatory response via NF-κB pathway in chicken livers. Moreover, excess Mn decreased T-AOC activity, indicating that Mn exposure caused oxidative stress. Furthermore, mRNA expression of above five HSP genes was up-regulated during Mn exposure. Oxidative stress triggered the increase of HSPs and the increase of HSPs mediated inflammatory response induced by Mn. In addition, there were time- and dose-dependent effects on Mn-caused chicken liver inflammatory injury. Taken together, HSPs participated in oxidative stress-mediated inflammatory damage caused by excess Mn in chicken livers via NF-κB pathway. For the first time, we found that oxidative stress can trigger HSP70 and HSPs can trigger poisoning-caused inflammatory damage, which needs to be further explored. This study provided a new insight into environmental pollutants and a reference for further study on molecular mechanisms of poisoning.

A spatial prioritization method for identifying potential eco-risk distributions of heavy metals in soil and birds

Geochemical approaches are popular for evaluations based on heavy metal concentrations in sediments or soils for eco-risk assessment. This study proposes a systematic geochemical approach (SymGeo) to explore six heavy metals in topsoils and bird tissues and organs of the target birds. We assume that the proposed approach based on field-collected heavy metals in topsoils and feathers can predict the areas with the potential risk of the heavy metals in birds. Finite mixture distribution modeling (FMDM) was used to identify background values of the heavy metal concentrations in topsoil. A spatial enrichment factor (EF), potential contamination index (PCI), contamination degree (Cod), and potential ecological risk index (PRI) based on FMDM results for topsoil, and a potential risk index (PRI_bird) of heavy metals in the birds, were utilized for systematic prioritization of high eco-risk areas. Using multiple EF, PRI, and Cod results and multiple PRI-based maps of the heavy metals in feathers, we systematically prioritized risk areas where there is a high potential for heavy metal contamination in the birds. Our results indicate that heavy metal concentrations in the feather, liver, and kidney are not spatially cross-autocorrelated but are statistically significantly correlated with some heavy metals in topsoil due to external and internal depositions. Further, multiple EF, Cod, and RI distributions for topsoil, along with the PRI of the feather, showed that adequate coverages for potential risk for birds were greater than 71.05% in the top 30% and 84.69% in the top 20% potential eco-risk priority area of heavy metals in bird liver and kidney. Hence, our proposed approach suggests that assessments of heavy metals in bird feathers and topsoils without bird organs can be utilized to identify spatially high-risk areas. The proposed approach could be improved by incorporating water and sediment samples to enhance the crowdsourcing and the species-specific data.

Heavy metal contamination in wild avian species inhabiting human-modified habitats

Health of birds and heavy metal toxicity are growing concerns in Pakistan because of irresponsible industrial waste management and farming practices. Eight species of common wild birds were studied from three different study sites which varied in the type of environmental pollution (Kasur: industrial waste, Lahore city: traffic pollution and Shahdara: mixed pollution of traffic, sewerage, and industry which the Ravi River accumulates). Heavy metal analysis of six heavy metals in the various organs of birds showed that there was no evidence of organ preference for metal accumulation in birds. Shahdara and Kasur with numerous industries both showed chromium concentrations above toxicity levels in 54.16% tissues of Granivorous birds, 60% of omnivorous birds, and 33.33% in tissues of carnivorous species. Statistical analysis proved that there is no correlation between weight of birds and accumulation of metals; it depends on food preference of birds and properties of the metals as bioaccumulators or biomagnifiers.

Assessing the association and predictability of heavy metals in avian organs, feathers, and bones using crowdsourced samples

Birds are bioindicators for research on the relationship between environmental heavy metal concentration levels and accumulation levels in bird tissues. We use roadkill samples, collected by citizen science participants, to investigate the accumulation levels and associations of seven heavy metals in internal organs (heart, liver, and kidney), feathers (primary and breast), and bones (sternum and femur) of two focal species, Amaurornis phoenicurus and Gallinula chloropus. We found that heavy metal accumulation varied by target tissue, and that variables are associated with bird species and heavy metal type. Although Zn and Cu were highest by concentration among both species, Cu was mostly accumulated in internal organs, As in feathers, and Pb in bones. Concentrations of As, Ni, and Pb in feathers of both focal species were lower than those reported in literature, whereas Cd and Cr were above toxic levels. The results also showed that spatial correlation for heavy metal concentration among bird tissues were weaker than non-spatial correlation, suggesting low spatial autocorrelations and variability. In addition, multiple regression analysis revealed significant correlation for Cr, As, and Pb estimations in A. phoenicurus heart, sternum, and kidney, respectively; and potentially Cr in G. chloropus femur by using feathers. These results support the feasibility of using feathers as indicators of As, Cr, and Pb heavy metal contamination to enhance our understanding of heavy metal accumulation in birds, although caution is required for feather-based estimations of Cd, Cu, and Ni concentration.

Feathers of Three Waterfowl Bird Species from Northern Iran for Heavy Metals Biomonitoring

Waterbirds are considered the effective sentinels of aquatic ecosystems contamination and their feathers are widely used as non-destructive biological tools for contaminant biomonitoring. In this work, we measure and evaluate the concentrations of lead, copper and zinc in the breast feathers of three species namely Fulica atra, Anas crecca and Anas platyrhynchos in the wetland National Park Boujagh. Levels of lead (Pb), copper (Cu) and zinc (Zn) were below the threshold that causes sub-lethal and reproductive effects. Significant differences in metal concentrations were found among bird species. The finding indicated that highest Pb and Zn concentrations were observed in common Coot. The effect of sex on heavy metal was observed for Pb in Anas platyrhynchos and while Cu, Zn in Anas crecca. Concentrations of metals were significantly (p < 0.05) higher in resident birds than in migratory. High levels of these heavy metals show that these birds can be used to monitor contamination in the wetland.

Metal concentrations in homing pigeon lung tissue as a biomonitor of atmospheric pollution

Atmospheric pollution in urban areas is a major worldwide concern with potential adverse impacts on wildlife and humans. Biomonitoring can provide direct evidence of the bioavailability and bioaccumulation of toxic metals in the environment that is not available with mechanical air monitoring. The current study continues our evaluation of the usefulness of homing pigeon lung tissue as a biomonitor of atmospheric pollution. Homing pigeons (1-2, 5-6, and 9-10+ year old (yo)) collected from Guangzhou during 2015 were necropsied and concentrations of cadmium (Cd), lead (Pb), and mercury (Hg) were measured in lung tissue. Lung Cd and Pb concentrations were significantly greater in 9-10+-year-old pigeons compared with those in other age groups, indicating their bioavailability and bioaccumulation. Lung Pb and Cd concentrations measured in 5-yo pigeons collected from Guangzhou during 2015 were significantly lower than concentrations reported in 5-yo homing pigeons collected from Guangzhou during 2011 and correlated with concentrations measured using mechanical air monitoring. In addition to temporal differences, spatial differences in concentrations of Cd, Pb, and Hg reported in ambient air samples and in pigeon lung tissues collected from Beijing and Guangzhou are discussed.

Deposition of absolute and relative airborne metals on eggshells: a field study

A biomonitoring field study was conducted to test the deposition of airborne metals on chicken eggshell. The goal was to correlate PM2.5 particle concentration in air, absolute (metals in air) and relative (metals in PM2.5 particles) metals, and metal accumulation on eggshell. The PM2.5 sample was collected for 8 h at different air pollution sites as well as an unpolluted site with glass fiber filters via a fine particulate sampler (with and without addition of eggshell). The PM2.5 particle concentration was high at a cement factory site and low at a sugar factory site. The highest absolute total mass of metal (total mass of all metals in air) was found in the traffic site, and the highest relative total mass of metal (total mass of all metals in PM2.5 particles) was found at the tannery factory. The accumulation of Zn and Pb in eggshell was high at the tannery and sugar factory sites, and Fe was high in the other areas. Three common metals including Cd, As, and Pb were found with significant positive correlation between absolute and relative metals with the metals accumulated in eggshell. The results concluded that the eggshells might be useful tools for monitoring the airborne metals.

Concentrations of lead and other elements in the liver of the white-tailed eagle (Haliaeetus albicilla), a European flagship species, wintering in Eastern Poland

As a top predator, the white-tailed eagle (Haliaeetus albicilla) may serve as a good indicator species, providing information about the bioavailability of contaminants and their transfer within the food chain. In this study, we aimed to determine the common sources of origin of 17 metals and other elements in the liver of white-tailed eagles, and to compare the variations in their hepatic concentrations by age (adults vs immatures) and sex (males vs females) in groups of white-tailed eagles wintering in Eastern Poland. The element concentrations followed the pattern of S > K > Na > Fe > Mg > Ca > Zn > Cu > Mn > Se > Pb > Hg > Cd > Cr > Sr > V > Sc. We found significant age-related differences in the hepatic concentrations of some of the elements. Adults showed higher concentrations of Pb, Cd, Ca, Fe, and Zn and lower concentrations of Cu and Se than immatures. These differences may be explained by age-related differences in wintering strategy (adults are sedentary, and immatures are migratory) and hunting skills (adults are more successful when hunting for agile prey). Our study indicates that ingested Pb ammunition poses a serious threat to the health and lives of white-tailed eagles in Poland (32% of the studied individuals had acute lead poisoning). Our study also indicates a serious need for banning the use of lead hunting ammunition in the parts of Europe (including Poland) where it is still allowed.

Heavy Metals in Liver and Brain of Waterfowl from the Evros Delta, Greece

The concentrations of six heavy metals (cadmium [Cd], chromium [Cr], copper [Cu], manganese [Mn], lead [Pb], and zinc [Zn]) were determined in liver and brain of nine species of waterfowl from the Evros Delta, one of the most important wetlands in Greece, to assess metal contamination and potential risk to waterfowl. Significant differences among species were found for hepatic Cr, Cu, Pb, and Zn; the highest levels of all metals were found in liver of mute swans. Cd increased significantly with age in both organs of wigeon; some differences were also observed between males and females of the same species. Feeding habits were found to significantly affect hepatic Cr, Zn, and Cu concentrations with greater concentrations found in herbivorous than omnivorous species. Several significant positive correlations between metals were detected mainly in liver samples, which were attributable either to their association to metallothioneins or to common routes of exposure of waterfowl. Hepatic and cerebral concentrations of Cd and Pb correlated positively. Given the discrepancies in the thresholds or critical levels of metals in tissues of waterfowl, our survey showed that environmental exposure to increased levels of heavy metals may threaten, at least to some degree, the populations of waterfowl wintering in the Evros Delta. In a small percentage of birds, values indicative of severe adverse effects were determined. Swans that had been found dead showed some of the highest values, whereas accumulation levels did not follow a consistent pattern among the ducks examined.

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.

Use of homing pigeons as biomonitors of atmospheric metal concentrations in Beijing and Guangzhou, China

Biomonitoring provides direct evidence of the bioavailability and accumulation of toxic elements in the environment and in the current study, homing pigeons were used as a biomonitor of atmospheric pollution in Beijing and Guangzhou, China. Cadmium (Cd), lead (Pb), and mercury (Hg) concentrations were measured in lung, kidney, and liver tissues of 25 homing pigeons collected from Beijing (n = 15) and Guangzhou (n = 10). Cadmium concentrations in all tissue and lung Pb concentrations were significantly greater in pigeons collected from Guangzhou compared to those collected from Beijing. Lung Cd and Pb concentrations corresponded to differences in ambient air concentrations between the two cities, suggesting that homing pigeons are valuable biomonitors of atmospheric metal contamination. Liver and kidney Hg concentrations were significantly greater in pigeons collected from Beijing compared to those collected from Guangzhou, while Hg concentrations in lung tissue were not significantly different. Results of the current study support a conclusion that homing pigeons provide valuable data for evaluating exposure and potential effects to environmental metal concentrations.

Trace element contamination in nestling black-tailed gulls (Larus crassirostris) in Korea

At Hongdo Island, Gyeongsangnam-do, Korea, a breeding site of black-tailed gull (Larus crassirostris), we collected nestlings from two locations: a "reference" site (n = 10) with no known source of lead contamination and "lighthouse" site (n = 10) with suspected lead contamination from leaded paint. Iron concentrations in the kidney and bone, manganese in the muscle, copper in the bone, lead in the muscle and bone, and cadmium in the liver, muscle, and bone at the reference site were significantly higher than at the lighthouse. Manganese concentrations in the liver and kidney, and lead in the kidney were significantly greater at the lighthouse than at the reference site. Iron, zinc, manganese, copper, lead and cadmium concentrations had tissue-specific accumulation at both sites. Lead concentrations in 10 % of livers and in 80 % of kidneys at the lighthouse, and in 20 % of livers from the reference were within a range considered toxic (>6.00 μg/g dw in the liver and kidney). Lead concentrations in 50 % of black-tailed gull nestlings at the reference and 80 % nestlings at the lighthouse were greater in livers than in bones, which is suggestive of acute lead exposure. For cadmium, all liver and kidney concentrations from two sites were at a level considered background in birds. Cadmium concentrations of every sample were higher in kidneys than in livers, suggestive of chronic cadmium exposure. Lead concentrations in gull nestlings in the present study were relatively higher than other gull species worldwide, but cadmium concentrations were relatively lower.

Comparison of the metal concentrations in organs of two bird species from western of Iran

This study was conducted to measure the concentration of several elements (Cd, Pb, Cu, and Zn) in organs of Coot, Fulica atra, and Mallard, Anas platyrhynchos, in order to: (1) determine the significant between metal concentrations in different organs (kidney, liver, pectoral muscle, and feather), (2) to evaluate species differences in metal exposure and accumulation, and (3) to study gender-related trends in metal accumulation. The metal concentrations in organs of F. atra and A. platyrhynchos decreased in the following order: Zn > Cu > Pb > Cd. These results revealed that there were no significant differences between males and females except for Cu in liver and feather, and Pb in kidney.

Age-dependent accumulation of heavy metals in liver, kidney and lung tissues of homing pigeons in Beijing, China

Biomonitoring provides direct evidence of the bioavailability and accumulation of toxic elements in the environment. In the current study, 1-2, 5-6, and 9-10+ year old homing pigeons collected from the Haidian District of Beijing during 2011 were necropsied and concentrations of cadmium, lead, and mercury were measured in liver, lung, and kidney tissue. At necropsy, gray/black discoloration of the margins of the lungs was observed in 98 % of the pigeons. There were no significant differences in metal concentrations as a function of gender. Cadmium concentrations in all tissues and Pb concentrations in the lung tissues were significantly greater in 9-10+ year old pigeons compared to other age groups indicating that Cd and Pb were bioavailable. Mercury concentrations were not significantly different among age groups. Cadmium concentrations in kidney and lung tissues of 9-10+ year old pigeons were similar to or exceeded concentrations of Cd reported in pigeons from another high traffic urban area and most wild avian species from Korea suggesting that Cd in this region of Beijing may be of concern. Homing pigeons provide valuable exposure and bioaccumulation data not readily available from air monitoring alone, thus providing information regarding potential health effects in wildlife and humans in urban areas. As environmental quality standards are implemented in China, homing pigeons will serve as a valuable bio-monitor of the efficacy of these actions.

The use of feathers of birds of prey as indicators of metal pollution

Published results concerning metal levels in feathers of birds of prey were listed and evaluated. Mercury concentrations have been studied most and the background values normally vary between 0.1 and 5 mg/kg dry weight the highest concentrations being in birds from aquatic food chains. Pollution causes elevated levels of mercury in feathers. The concentrations of cadmium, copper, lead and zinc show reasonable variation between species, areas and time periods. Feathers of birds of prey have proved to be good indicators of the status of environmental heavy metal pollution. Special attention should be paid to clean sampling and preparation of samples. Interpretation of the results requires knowledge on food habit, molting and migration patterns of the species. Several species representing different food chains should be included in comprehensive monitoring surveys. Chick feathers reflect most reliably local conditions.

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.

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.

Temporal trends (1989-2011) in levels of mercury and other heavy metals in feathers of fledgling great egrets nesting in Barnegat Bay, NJ

There is an abundance of data for levels of metals from a range of species, but relatively few long-term time series from the same location. In this paper I examine the levels of arsenic, cadmium, chromium, lead, manganese, mercury and selenium in feathers from fledgling great egrets (Ardea alba) collected at nesting colonies in Barnegat Bay, New Jersey from 1989 to 2011. The primary objectives were to test the null hypotheses that (1) There were no temporal differences in metal levels in feathers of fledgling great egrets, and (2) Great egrets nesting in different areas of Barnegat Bay (New Jersey) did not differ in metal levels. There were significant yearly variations in levels of all heavy metals in feathers of fledgling great egret, but levels decreased significantly from 1989 to 2011 only for lead (1,470 ppb to 54.3 ppb), cadmium (277 ppb to 30.5 ppb), and manganese (only since 1996; 2,669 ppb to 329 ppb)). Although mercury levels decreased from 2003-2008 (6,430 ppb to 1,042 ppb), there was no pattern before 2003, and levels increased after 2008 to 2,610 ppb in 2011. Lead, cadmium, chromium, manganese and mercury were higher in feathers from great egrets nesting in the northern part of the bay, and selenium was highest in feathers from mid-bay. The lack of a temporal decline in mercury levels in feathers of great egrets is cause for concern, since the high levels in feathers from some years (means as high as 6,430 ppb) are in the range associated with adverse effects (5,000 ppb for feathers).

Heavy metal contamination and metallothionein mRNA in blood and feathers of Black-tailed gulls (Larus crassirostris) from South Korea

The objectives of this study were to determine levels of heavy metal in the feathers and blood of Black-tailed gulls (Larus crassirostris), to evaluate metallothionein (MT) mRNA level in Black-tailed gulls on three independent islets, and to examine the correlation between heavy metal concentrations and MT mRNA expression. Eleven heavy metals (Al, Cd, Mn, Pb, Cr, Fe, Cu, Zn, Se, Hg, and As) were investigated in blood and feathers of 65 chicks from breeding colonies (Seomando, Hongdo, and Dokdo islet) of South Korea in 2010. Heavy metals were assayed by PerkinElmer NexION 300 inductively coupled plasma mass spectrometry. The mean concentrations of non-essential heavy metals were found to blood containing Cd (0.002 ~ 0.02 ppm), Pb (0.06 ~ 0.18) ppm, Hg (0.03 ~ 0.05) ppm, and As (0.26 ~ 0.48 ppm), and feather containing Cd (0.05 ~ 0.30 ppm), Pb (2.47 ~ 10.80 ppm), Hg (1.18 ~ 1.57 ppm), and As (0.15 ~ 0.44 ppm). Chicks on Seomando islet showed the highest levels of metals (Cd, Pb, Mn, Cr, Cu, and Se in blood; Al, As, Mn, Cr, Fe, Cu, and Se in feathers) among the colonies. Concentrations of Pb and Hg in feathers were the highest on Hongdo, and the levels of Cd and Zn in feathers were the highest on Dokdo islet. MT mRNA in the blood of Black-tailed gulls was relatively higher in gulls from Seomando than in gulls from Hongdo and Dokdo islet. MT mRNA level is thus positively correlated to heavy metal concentrations in Black-tailed gulls.

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).

A method of identifying priority spatial patterns for the management of potential ecological risks posed by heavy metals

An approach of identifying priority spatial patterns in response to different ecological risk levels associated with heavy metals (HM) is proposed. First, ecological hotspots (EH) are delineated by integrating NDVI-based assessment with the impact assessment of anthropogenic impact sources. Second, the HM potential ecological risks index (PERI) is calculated and spatially interpolated. Finally, the EH with different PERI values are identified through logic calculation. Study results show that 45.2% of the study region has low HM risks, 53.2% with moderate HM risks, and only 1.6% with high HM risks. In addition, the percentage of EH with low HM risks is 6.5%; the percentage with moderate HM risks is 5.4%; and the percentage with high HM risks is 0.4%. The EH with low and moderate HM ecological risks are proposed to be the regions in priority for management. This approach is potentially useful to HM ecological risk assessment and HM contamination management around the world.

Assessment of trace-metal concentrations in Western Reef heron (Egretta gularis) and Siberian gull (Larus heuglini) from southern Iran

The objective of the present study was to investigate the levels of heavy metals, namely, chromium, copper, cobalt, nickel, and iron, in Western Reef heron (Egretta gularis) (n = 15) and Siberian gull (Larus heuglini) (n = 15) to (1) compare metal concentrations between two bird species with different trophic level, molting pattern, and life strategy; (2) examine species- and sex-related variations in trace-metal accumulation; and (3) determine the significance between heavy-metal concentrations in kidney, liver, and pectoral muscle. Bird samples were collected from November to December 2010 throughout the Hara Biosphere Reserve, and heavy metals were assayed by using a Shimadzu AA 680 flame atomic absorption spectrophotometer; the results were given as μg/g dry weight. Metal concentrations were different between the bird species as well as among bird tissues, but there was no difference (except chromium and iron in kidney) between sex (male vs. female). Mean levels in kidney of Western Reef heron and Siberian gull were chromium (0.96, 2.32 μg/g), copper (6.31, 10.55 μg/g), cobalt (0.12, 0.14 μg/g), nickel (1.13, 1.32 μg/g), and iron (37.92, 39.64 μg/g), respectively, whereas in liver they were chromium (1.05, 2.75 μg/g), copper (8.93, 12.63 μg/g), cobalt (0.09, 0.17 μg/g), nickel (1.1, 2.27 μg/g), and iron (34.03, 44.21 μg/g), respectively. Results showed that heavy-metal concentrations in Western Reef heron were decreased in the sequence iron > copper > nickel > chromium > cobalt, whereas in Siberian gull they were decreased in the sequence iron > copper > chromium > nickel > cobalt. Results also showed that in both species, the highest chromium and nickel concentrations were measured in female birds and the lowest in male birds, whereas the highest copper, cobalt, and iron (except iron in liver) concentrations were measured in male birds and the lowest in female birds.

Contaminations of metal in tissues of Siberian gull Larus heuglini: gender, age, and tissue differences

The objective of the present study was to investigate the levels of metals, namely cadmium, lead, and zinc, in Siberian gull (Larus heuglini) (n = 15), in order to: (1) examine the sex and gender related variation in trace metal accumulation, and (2) to determine the significant between metal concentrations in the kidney, liver, and pectoral muscle. The concentrations were different between the tissues of bird as well as among the interaction (sex × age), but this difference (except cadmium in liver and zinc in kidney) between the gender (male and female) and age (adult and juvenile) didn't exist. Results showed that the metal concentrations in the Siberian gull were decreased in sequence of kidney > liver > muscle. The cadmium, lead, zinc concentration overall means they were measured as 2.2 ± 0.7, 8.8 ± 2.5, and 91.1 ± 37. 1 μg/g for kidney, 1.1 ± 0.2, 5.1 ± 0.8, and 68.3 ± 27.8 μg/g for liver, and 0.8 ± 0.1, 3.4 ± 0.6, and 34.4 ± 23.2 μg/g for pectoral muscle, respectively.

Metal levels in livers of waterfowl from Korea

This study presents concentrations of heavy metals (iron, zinc, manganese, copper, lead and cadmium) in livers of white-fronted geese (Anser albifrons), eurasian wigeons (Anas penelope), mallards (Anas platyrhynchos) and spot-billed ducks (Anas poecilorhyncha) from Korea in February 2006 and 2008. Iron concentrations were significantly lower in spot-billed ducks than in other species (ANOVA, p<0.001). Zinc concentrations were greater in white-fronted geese and spot-billed ducks than in eurasian wigeons and mallards (ANOVA, p<0.001). Manganese and copper concentrations in white-fronted geese were significantly higher than in other species (ANOVA, p<0.001). Cadmium concentrations were significantly higher in mallards and spot-billed ducks than in white-fronted geese (ANOVA, p=0.007). However, lead concentrations did not differ among species. Iron, zinc, manganese and copper concentrations from this study were within the range of other waterfowl studies. Therefore, we suggest that essential elements such as iron, zinc, manganese and copper are within normal range and are maintained there by normal homeostatic mechanism. Twenty individuals (29.0 percent) exceeded the threshold level for abnormal lead exposure (5 μg/g dry weight) in waterfowl in this study and it is a higher proportion than in herons, egrets and owls from Korea. We suggest that the result was attributed to ingestion of lead shot and sinkers. However, cadmium concentrations in waterfowl except one specimen were within the background concentrations for wild birds. In livers of four waterfowl species found in Korea, lead and cadmium concentrations were similar to previously reported in other geese and ducks; except for poisoning of lead shot or sinkers as shown in earlier studies.

Biological monitoring of heavy metal contaminations using owls

Iron, manganese, copper, lead and cadmium were measured in the livers, muscles, kidneys and bones of Eurasian Eagle Owls (Bubo bubo), Brown Hawk Owls (Nixos scutulata) and Collared Scops Owls (Otus lempiji) from Korea. Iron concentrations by tissue within species did not differ, but there were significant differences among tissues across all species. Manganese and copper concentrations in muscles, kidneys and bones, but not livers, differed among species and also differed among tissues in the three owl species. We suggest that manganese and copper concentrations from this study were far below the level associated with their toxicity. Lead concentrations significantly differed among all species for livers and bones, and among tissues for each species. Cadmium concentrations were significantly different among species for all tissues and among tissues in Eurasian Eagle Owls and Collared Scops Owls. For most samples, lead concentrations in livers and bones, and cadmium in livers and kidneys, were within the background levels for wild birds. For some Eurasian Eagle Owls and Collared Scops Owls, lead concentrations were at an acute exposure level, whilst lead concentrations were at a chronic exposure level in Brown Hawk Owls. Cadmium concentrations were at a chronic exposure level in all three owl species. Acute and chronic poisoning was significantly correlated between indicator tissues. We suggest that lead and cadmium contamination in Eurasian Eagle Owls may reflect a Korean source, Brown Hawk Owls may reflect Korean and wintering sites, and Collared Scops Owls may reflect breeding and/or wintering sites.

Bioaccumulation of trace elements in trophic levels of wetland plants and waterfowl birds

Present study investigates relationships between total and bioaccessibility of trace elements (Cd, Co, Cr, Cu, Mn, NI, Pb, V, and Zn) concentrations in sediment and their bioaccumulation in species in Shadegan wetland in southwest of Iran. Bioavailability factor (BAF) and translocation factor (TF) were calculated in plants and trophic transfer factor (TTF) was determined in bird species. For this purpose, sampling of sediments, aquatic plants including Phragmites australis, Typha australis, Scripus maritimus and two bird species encircling Porphyrio porphyrio and globally threatened Marmaronetta angustirostris were carried out during winter 2009. Result of chemical analysis show that bioaccessibility concentrations of Mn (8.31 mg/kg), V (1.33 mg/kg), and Pb (1.03 mg/kg) are higher than other metals. The uptake trend of trace elements in plant decreases as root > stem > leaf. Accumulation levels of trace elements in different tissues of P. porphyrio and M. angustirostris are almost identical and considerable. Accumulation and toxicity of Cd in birds is more than plants. In addition, BAF of V, Pb, and Cr indicates high accumulation by plants and great pollution rate in the area of study. In S. maritimus TF for Mn, Cu, Pb, and V are high whereas in T. australis, Cu and Pb posses the highest TF. Also Cr, Co, Mn, Ni, and Zn have higher TF from stem to leaf than root to stem in P. australis. Finally, TTFs were compared in various bird species.

Monitoring of heavy metal contamination using tissues of two ardeids chicks, Korea

This study presents concentrations of iron, zinc, manganese, lead and cadmium in livers and kidneys of Little Egret Egretta garzetta (n = 10) and Black-crowned Night-Heron Nycticorax nycticorax (n = 10) chicks from Pyeongtaek, Gyeonggi-do, Korea. Essential element concentrations such as iron, zinc and manganese did not differ between both species chicks in livers and kidneys, but lead and cadmium concentrations were significantly greater in both tissues of Little Egret chicks (lead 2.78 +/- 4.06 microg/g wet weight, cadmium 10.3 +/- 12.8 kg/g wet weight) than in those of Black-crowned Night-Heron chicks (lead 0.92 +/- 0.73 microg/g wet weight, cadmium 1.00 +/- 1.00 kg/g wet weight). Lead and cadmium concentrations in livers of Black-crowned Night-Heron chicks were highly related to sediment and/or prey concentrations of their foraging sites in Korean studies. It shows that lead and cadmium concentrations in livers of heron chicks can reflect those of surrounding environment of breeding sites. In this study, cadmium concentrations were higher in kidneys than in livers and it's not recent high-level exposure but chronic background exposure to cadmium contamination around breeding site. Therefore, we suggest that cadmium concentrations in livers and kidneys can be used as a bioindicator of acute and/or chronic local contamination.

Effect of dietary cadmium on lipid metabolism and storage of aquatic bird Cairina moschata

In environment, birds often fast in connection with breeding, migration or drastic climatic conditions and need to mobilize lipid reserves during these periods. The impairment of lipid metabolism by cadmium (Cd; 1 mg kg(-1) added in diet) was investigated on palmiped Cairina moschata. Expression levels of genes involved in lipid metabolism, mitochondrial metabolism and detoxification were investigated in liver and muscle of ducks. Lipid content in muscle and liver were analysed and plasma triglycerides were quantified. After 20 days, ducks exposed to Cd displayed a lower body weight and lower lipid content in liver than controls. In muscle, the increase of lipid content was only significant for control ducks but not for exposed ducks. Exposed ducks appeared unable to sufficiently transport and store lipids into peripheral tissues. Cd impairs lipid metabolism by several ways. First, Cd triggered the down-regulation of fatty acids synthesis in liver even if the NADPH production and the mitochondrial metabolism are enhanced, suggesting a stronger energy needs. Secondly, the associated decrease of plasma triglycerides and lipoprotein lipase activity with Cd are consistent with impairment of lipids storage in peripheral tissues.