Environmentally acquired lead, cadmium, and manganese in the cattle egret, Bubulcus ibis, and the laughing gull, Larus atricilla

Heavy Metals in the Liver, Kidney, Brain, and Muscle: Health Risk Assessment for the Consumption of Edible Parts of Birds from the Chahnimeh Reservoirs Sistan (Iran)

The concentrations of four heavy metals, zinc (Zn), lead (Pb), nickel (Ni), and cadmium (Cd), were determined in the liver, kidney, muscle, and brain of nine species of birds from the Chahnimeh Sistan from Iran to assess the metal levels and the potential risk to birds and to the people who eat them. Significantly higher levels of all metals were found in the brain than in the other tissues of other birds. There were no significant gender differences in heavy metals in all tissue. The levels of Pb, Cd, Ni, and Zn in the liver and kidney varied as a function of feeding habitats; the median levels were significantly higher in invertebrate predators than they were for fish predators and omnivorous species. Short-distance migrant birds had significantly higher median levels of heavy metals in the liver and kidney than long-distance migrant birds. Ni levels in the liver and kidney tissues in 56% of birds were higher than the critical threshold levels for effects in birds. Our data indicate that environmental exposures to metals were higher in the wintering populations of birds in the Chahnimeh of Sistan from Iran than elsewhere. Concentrations of Zn, Pb, and Cd in a small percentage of birds were above toxicity levels. However, 56% of liver and kidney samples for nickel were above toxicity levels. Determining the exposure frequency and daily intake of birds, the hazard quotient for edible tissues (kidney, liver, and muscle) of these birds showed that their consumption may provide health risk to people consuming them.

Heavy metals in liver, kidney, brain, and muscle slender-billed gull (Chroicocephalus genei) from south-eastern Iran

The concentrations of four heavy metals nickel (Ni), cadmium (Cd), lead (Pb), and zinc (Zn) were determined in liver, kidney, muscle, and brain tissues of 40 slender-billed gulls (Chroicocephalus genei) from the Chahnimeh water reservoirs of Sistan and the Oman Sea coast of Iran. There were significant differences between Ni, Cd, Pb, and Zn concentrations observed in the liver and brains of birds from the Oman Sea coast than in the liver and brains of gulls from the Chahnimeh water reservoirs (P < 0.05). Higher levels of Pb, Cd, and Zn were found in the brain and liver of gulls than in the kidney and muscles tissues. There were significant gender differences in heavy metals in liver and brain tissue. In gulls from the coast of Oman Sea, all four elements (Cd, Pb, Ni, and Zn) were positively correlated with levels in all organs, and except for muscle, the elements were positively correlated with the other elements in the other tissues (except Ni in the brain). Thus, the pathways and sources of entry for the elements are similar, and the pathways for accumulation of these elements, and the reactions of different organs of the body to these elements, are very similar. Also, 40% of gulls in Oman Sea coast had levels of lead in the brain (>5 μg g^{-1 -1} d.w) that were above the adverse effect levels, Ni concentrations in the liver of slender-billed gull in Oman Sea coast (100 %) and Chahnimeh water reservoirs (90 %) were above toxic levels (> 3 μg g^-1 d.w), and 80% of Ni concentration in kidneys in gulls from the Oman Sea coast and Chahnimeh water reservoirs were higher than the toxicity levels (> 10 μg g^-1 d.w).

Lead (Pb) in the tissues of Anatidae, Ardeidae, Sternidae and Laridae of the Northern Hemisphere: a review of environmental studies

Due to the ability of birds to travel long distances in the air, the potential feeding area of each individual is much larger than that of typical terrestrial animals. This makes birds a convenient indicator of environmental lead (Pb) pollution over large areas, in particular areas of inland and coastal waters. The aim of this study was to assess the concentrations of Pb in various organs of water birds from a variety of locations. The focus was on ducks, geese and swans (Anatidae); herons and egrets (Ardeidae); terns (Sternidae); and gulls (Laridae). This article describes the level of lead in the most commonly studied tissue types: feathers, bones and the liver. The study also presents data concerning the concentration of lead in the eggs of water birds. The highest levels of lead pollution can be observed in China and Korea, related to their high level of industrialization. In Iran too, environmental lead pollution is high, likely due to the developed petrochemical industry. Lead pollution in Japan, as well as in Western European countries (Spain, France, Italy), seems to be much lower than in China, India or Iran. Nevertheless, the level of pollution in Europe is higher than satisfactory, despite the introduction of a number of bans related to, for example, the use of leaded petrol or lead-containing paints. Finally, the USA and Canada appear to be the areas with the lowest lead pollution, possibly due to their low population densities.

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.

Baseline Blood Pb Concentrations in Black-Necked Stilts on the Upper Texas Coast

There are no known biological requirements for lead (Pb), and elevated Pb levels in birds can cause a variety of sub-lethal effects and mortality. Historic and current levels of Pb in mottled ducks (Anas fulvigula) suggest that environmental sources of Pb remain available on the upper Texas coast. Because of potential risks of Pb exposure among coexisting marsh birds, black-necked stilt (Himantopus mexicanus) blood Pb concentrations were measured during the breeding season. Almost 80 % (n = 120) of 152 sampled stilts exceeded the background threshold (>20 μg/dL) for Pb exposure. However, blood Pb concentrations did not vary by age or gender, and toxic or potentially lethal concentrations were rare (<5 %). Consistent, low-level blood Pb concentrations of black-necked stilts in this study suggest the presence of readily bioavailable sources of Pb, although potential impacts on local stilt populations remain unclear.

Heavy metal distribution in some wild birds from Korea

This study presents concentrations of heavy metals (manganese, zinc, lead, and cadmium) in tissues in six orders of Korean wild birds (n=37), 2000-2002. Zinc, manganese, lead, and cadmium concentrations in all tissues were highest in ancient murrelets (Synthliboramphus antiquus). Essential elements in Korean wild birds were within the normal range for wild birds and are maintained there by a normal homeostatic mechanism. Lead concentrations in livers of almost all birds were within the background levels. Cadmium concentrations in livers and kidneys of ancient murrelets exceeded background levels for wild birds, but other birds were within the normal range. Acute and chronic contaminations of lead and cadmium levels differed among groups (or species). We suggest that differences in lead and cadmium concentrations among groups are because of differences in diet and habitat. In ancient murrelets, zinc and manganese concentrations correlated with their cadmium concentration in livers. Zinc, manganese, and cadmium concentrations in murrelet livers were also higher than in other species. Therefore, we suggest that high zinc and manganese concentrations in ancient murrelets were related to their high cadmium concentrations.

Heavy metal distribution in chicks of two heron species from Korea

This study presents concentrations of iron, manganese, zinc, copper, lead, and cadmium in tissues of black-crowned night heron (Nycticorax nycticorax) (n = 8) and grey heron (Ardea cinerea) (n = 9) chicks from Pyeongtaek heronry, Gyeonggi-do, Korea, 2001. Iron (respectively, 45.8 +/- 24.0 microg/wet g, 155 +/- 123 microg/wet g), zinc (38.3 +/- 5.34 microg/wet g, 50.9 +/- 14.0 microg/wet g), and copper (9.93 +/- 2.26 microg/wet g, 30.2 +/- 12.9 microg/wet g) concentrations in feathers, manganese concentrations in livers (3.26 +/- 0.68 microg/ wet g, 1.50 +/- 0.58 microg/wet g), kidneys (1.43 +/- 0.27 microg/wet g, 0.84 +/- 0.34 microg/wet g), and bones (1.34 +/- 0.50 microg/wet g, 3.17 +/- 1.31 microg/wet g) were different between black-crowned night heron and grey heron chicks. Lead concentrations in bones (0.11 +/- 0.04 microg/wet g, 0.61 +/- 0.42 microg/wet g) and cadmium concentrations in liver (13.5 +/- 2.30 microg/wet kg, 10.3 +/- 1.59 microg/wet kg), kidney (6.61 +/- 2.54 microg/wet kg, 2.31 +/- 1.29 microg/wet kg), and muscle (5.25 +/- 5.91 microg/wet kg, 1.37 +/- 0.90 microg/wet kg) differed between chicks of the two heron species. The differences of heavy metal concentrations in tissues in herons and egrets were reported to other similar studies. Heavy metal concentrations for both heron species were at background levels. In both species, lead concentrations were higher in livers than in bones and cadmium concentrations were higher in livers than in kidneys. We suggest that it is not chronic exposure but acute exposure to lead and cadmium contamination around breeding site that leads to these observations. Therefore, lead and cadmium concentrations in tissues can be used as a bioindicator of acute local contamination.

A new index for evaluation of cadmium pollution in birds and mammals

The degree of cadmium (Cd) contamination in wildlife is often used as an indicator in the environmental monitoring of Cd poisoning. However, previous studies have not clarified the correlation between levels in wildlife and levels in the environment by comparing levels among different species of animals; therefore, assessing the level of pollution in this manner is not considered a reliably accurate indicator of levels in the environment. The aim of this study was to establish a new indicator for the non-polluted warm-blooded animals, one that is not species-dependent, which will facilitate using different species for Cd monitoring. First, the previous publications regarding Cd contents in wildlife, 27 reports in which Cd contents were represented as arithmetic means and described for both kidney and liver were selected. A regression line (CSRL) between Cd contents of kidney and that of liver was obtained in a high correlation coefficient (R (2) = 0.943, P < 0.01). The mean values from land and waterfowl, terrestrial mammals, seabirds, marine mammals, and non-polluted humans were located on the line and aligned in order. CSRL might allow an accurate determination of whether an animal is polluted by Cd. CSRL was confirmed using well-established and widely recognized pollution models such as Itai-itai patients and Cd-exposed experimental animals. The Cd contents from these models were located in different positions relative to CSRL depending on the level of contamination. Thus, this new indicator determining the Cd-pollution status of animals would be useful for environmental monitoring.

Trace metal concentrations are higher in cartilage than in bones of scaup and pochard wintering in Poland

Bones and cartilage of two species of diving ducks: the scaup Aythya marila (n=24) and the pochard A. ferina (n=24) were studied. Scaup is protected in Poland where it spends only the winter, while pochard is a game bird, abundant and breeding in Poland. In winter, the two species form large flocks off the southern coast of the Baltic, particularly in the Szczecin Lagoon where they were collected for this study. The bones and cartilage (trachea) were assayed for concentrations (dry weight-based) of three essential metals: iron (Fe), copper (Cu), and zinc (Zn); concentrations of the two toxic metals: lead (Pb) and cadmium (Cd) were assayed as well. These hard tissues of the two species showed the following order of metal concentrations Zn>Fe>Pb>Cu>Cd. In scaup and pochard bones, the respective geometric mean concentrations of Zn, Fe, Pb, Cu, and Cd were 94.4 and 102.0; 20.2 and 24.7; 6.2 and 9.6; 0.19 and 0.26; 0.114 and 0.162 mg/kg. The levels of all the metals in cartilage (Zn 149.1 and 165.8; Fe 58.4 and 116.3; Pb 10.6 and 14.9; Cu 1.41 and 3.31; Cd 0.144 and 0.175 mg/kg, respectively) were higher than in the bones of A. marila and A. ferina. However, statistically significant differences were found in respect to the essential metals only (Zn, Fe, Cu). The inter-species comparisons showed the two species to differ in their cartilage concentrations of Fe, Cu, Zn, and Cd and in their bone concentrations of Pb and Cd. In each case, the pochard exhibited higher concentrations of metals. This study showed distinct differences between trace element accumulation by two heavily mineralised avian body parts: leg bones (tarsometatarsus) and cartilage (trachea). The results are in agreement with data reported by other workers who analysed trace metals in cartilaginous and bone components of the femoral head in homoiotherm vertebrates, including humans. Therefore it is important that intra- and inter-species comparisons of hard biological components be based on corresponding body parts, and that relevant biochemical and ecotoxicological research be pursued.

Heavy metal concentrations in diet and livers of Black-crowned Night Heron Nycticorax nycticorax and Grey Heron Ardea cinerea chicks from Pyeongtaek, Korea

This study presents concentrations of iron, manganese, zinc, copper, lead and cadmium in diet and livers of Black-crowned Night Heron Nycticorax nycticorax and Grey Heron Ardea cinerea chicks from Pyeongtaek, Gyeonggi-do, Korea. Heavy metal concentrations of heron chicks were not related to concentrations in the diet. Copper concentrations were significantly greater in the diet of Black-crowned Night Herons (geometric mean = 13.6 wet microg/g) than Grey Herons (7.45 wet microg/g), other metal concentrations did not differ between the diet of two species. Manganese (respectively 3.20 wet microg/g, 1.41 wet microg/g) and cadmium (respectively 13.4 wet microg/kg, 1.41 wet microg/kg) concentrations were higher in livers of Black-crowned Night Heron chicks than Grey Heron chicks, but zinc, iron, copper and lead concentrations in livers did not differ in between two herons. The essential elements were at background levels, however copper concentrations were relatively higher than previously reported from Korea. Lead and cadmium concentrations were within background levels for herons.

Trace elements and pollutants concentrations in shorebirds from Yeongjong Island, Korea in the East Asian-Australian migration flyways

This study presents concentration levels of trace metals and pollutants (zinc, manganese, copper, lead, and cadmium) in tissues (livers, kidneys, muscles, and bones) of shorebirds from Yeongjong Island, Korea, in the East Asian-Australian migration flyways. Essential trace elements, zinc concentrations in kidneys, and copper concentrations in muscles significantly differed among shorebirds, but manganese concentrations did not differ in each tissue. We suggest that essential elements are within normal range and are maintained there by normal homeostatic mechanism. Lead concentrations in livers, kidneys, muscles, and bones were significantly different among shorebird species. Lead concentrations in livers of Kentish Plovers, Mongolian Plovers, Dunlins, and Great Knots were less than the toxic level, and lead concentrations in livers of Terek Sandpipers were at the background level. Cadmium concentrations in livers, kidneys, muscles, and bones did not vary among shorebirds, and concentrations of cadmium in livers and kidneys were at background level in all shorebirds. In livers of Dunlins from Yeongjong Island, lead and cadmium concentrations were higher than other locations previously reported.

Heavy metal contamination in little owl (Athene noctua) and common buzzard (Buteo buteo) from northern Italy

In this study, two raptor species, the common buzzard (Buteo buteo) and the little owl (Athene noctua), were investigated for lead and cadmium concentrations, using liver, kidneys, pectoral muscle, sternum bone, and feathers. All the collected birds died at the Centro Recupero Rapaci of Lega Italiana Protezione Uccelli in Sala Baganza (Parma, Italy). They arrived alive at the Centro between November 1998 and November 1999 but died or were put to death as a consequence of injuries or other ailments. The results of the investigation do not show an excessive exposure to cadmium, whereas some interesting data have emerged in the case of lead. The concentration of the latter in the liver and in the bone of two little owls seem to suggest the possibility of chronic exposure. The high values found in one common buzzard, on the other hand, suggest an acute exposure and, probably, a case of lead shot ingestion.

Cadmium, chromium and lead contamination of Athene noctua, the little owl, of Bologna and Parma, Italy

A study was conducted to determine cadmium, chromium and lead concentrations in liver and brain of 52 little owls (Athene noctua) from two provinces of Emilia Romagna region, with the aim of furnishing indirect information concerning contamination of their habitat, also considering possible environmental dispersion of the metals. Metal analysis was performed by atomic absorption spectrophotometry with graphite furnace. Variance analysis with sampling area, gender and age shows that no statistical difference was found for gender, while a significant difference (P<0.05) was found for cadmium and lead, but not for chromium, when sampling areas and age were of concern. For all metals highest mean concentrations were found in liver (170 ppb for cadmium, 297 ppb for chromium and 312 ppb for lead). These levels can be considered as indicative of chronic exposure to low and "background" amounts of pollutants and they are of no toxicological concern, as they are always well below the toxic thresholds defined for each metal. The present study can be considered as a starting point for further analyses, aimed to the definition of any possible subtle effect (e.g. effects on enzymes activity) and of any possible correlation between levels of pollutants and appearance of possible adverse effects. It also furnished useful data for diagnostic cases and potentially for monitoring local contamination.

Lead in the diet and body tissues of dunlins, Calidris alpina, from the Bristol Channel, UK

Lead concentrations were determined in the organs of a shorebird, the dunlin, in its main invertebrate prey, and in sediments collected from five sites in the Bristol Channel. The highest sediment concentrations were found in the Taff Estuary (97 microg g(-1) dry mass). The highest concentrations in invertebrates were found in the upper Severn Estuary (45 microg g(-1) dry mass in Nereis diversicolor). In dunlins, the highest concentrations were found in the sternum (25 microg g(-1) dry mass in males), followed by the beak, legs, kidney, liver and pectoral muscle. Adult males contained significantly higher concentrations (ca 20%) than adult females, and in some cases adults had significantly higher concentrations than first year birds (36% higher in the case of the sternum). Lead concentrations tended to increase throughout the winter, being 37-115% higher in the spring. Birds were able to purge themselves of a substantial portion of their body lead burdens, probably during the autumn moult.

Heavy metals in the brain of long-tailed duck (Clangula hyemalis) wintering in the Pomeranian Bay, Poland

Males (n = 34) and females (n = 23) of long-tailed duck (Clangula hyemalis) collected on the southern coast of the Baltic Sea in winter were studied to determine brain tissue concentration of iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), and cadmium (Cd). There were no significant differences in the concentration of metals between males and females, except for Cd, the concentration of which in male brains was twice that of the females. In the brains of 20 birds (41% male and 26% female), the lead (Pb) concentration exceeded 1 microgram/g wet wt. In all the duck brains examined, Spearman correlation coefficients were significant and positive for Zn-Mn, Cu-Mn, Cu-Fe, and Pb-Fe; a negative correlation was found for Pb-Zn. Additionally, female brains showed a positive correlation between Pb and Fe. The results obtained were compared with literature data for diving and nondiving anseriforms and birds of other taxa. It seems that concentration of heavy metals in the brain tissue of birds reflect natural adaptations (e.g., for diving) as well as effects of environmental pollution.

Heavy metals in seaducks and mussels from misty fjords national monument in Southeast Alaska

Quartz Hill, in Misty Fjords National Monument near Ketchikan, Alaska, is the site of a proposed molybdenum-producing mine. To provide baseline data for use in post-development comparisons, we analyzed tissues of Barrow's goldeneyes (Bucephala islandica), common mergansers (Mergus merganser), and blue mussels (Mytilus edulis) for seven heavy metals that could potentially be released into the environment as a result of mining operations. Specimens were collected in 1980, 1981, and 1982 from two fjords likely to be used for discharge of tailings from the proposed mine and from two control fjords. Concentrations of arsenic, cadmium, copper, chromium, molybdenum, lead, and zinc were measured in soft tissues of mussels and in kidney, liver, and muscle of birds. The highest mean concentrations of metals found in bird tissues were 55.7 ppm dry weight cadmium in kidneys and 154 ppm dry weight zinc in livers of Barrow's goldeneyes. Concentrations of several metals in blue mussels differed among seasons and locations, but the most significant finding in mussels was a maximum mean cadmium concentration of 9.6 ppm dry weight, a level higher than normally found in undisturbed areas. With the exception of 104 ppm dry weight cadmium in the kidney of one common merganser and 12.7 ppm dry weight lead in the kidney of another, concentrations of other metals in seaduck and mussel tissues were low, consistent with what would be expected for a pre-development environment. Molybdenum was found in low concentrations (<10 ppm dry weight) in all avian kidney samples and most liver samples, but was not detected in blue mussels.

Heavy metal concentrations in feathers of common loons (Gavia immer) in the Northeastern United States and age differences in mercury levels

Feathers serve as a useful, non-destructive approach for biomonitoring some aspects of environmental quality. Birds can eliminate over 90% of their body burden of mercury by sequestration in growing feathers, and they molt their feathers at least annually. Thus mercury concentrations should not vary in avian feathers as a function of age. We tested the null hypothesis that there are no age differences in the concentrations of mercury, lead, cadmium, selenium, copper, chromium and manganese in the feathers of immature and adult common loons Gavia immer from the Northeastern United States where the species is declining. Adults had significantly higher mean levels of mercury (20245 ppb) than immature loons (9677 ppb), but there were no age-related differences for other elements. Even with the small number of immatures, females had significantly higher levels of mercury than males, although the gender difference was not significant for adults.

Mercury bioaccumulation in organisms from three Puerto Rican estuaries

We analyzed mercury levels in shrimp (Palaemonetes sp.), Blue Crabs (Callinectes sp.), fish (Tarpon Megalops atlantica and Tilapia Tilapia mossambica), lizards (Ameiva exsul), Cattle Egret (Bubulcus ibis) and Moorhen (Gallinula chloropus) in three estuaries in Puerto Rico in 1988. There were no quantifiable concentrations greater than the method detection limit of mercury in shrimp, crabs and lizards from any site. Mercury levels were also below detection limits in Tilapia, except for specimens collected at Frontera Creek, allegedly contaminated with mercury. However, mercury levels ranged from 92-238 μg/kg (wet weight) in Tarpon, a predaceous fish that feeds on smaller fish. Few of the birds had detectable levels of mercury. Our results indicate relatively low concentrations of mercury in biota collected in all of the three estuaries at most trophic levels, although 10 of 12 Tarpon fillet samples from Frontera had detectable mercury compared to 3 of 12 fillet samples for the other two lagoons.

Tissue levels of lead in experimentally exposed herring gull (Larus argentatus) chicks

Two-day-old herring gull (Larus argentatus) chicks were injected with either 0.1 or 0.2 mg lead/g body mass and were sacrificed at 45 d of age. Control birds were injected with sterile water. We examined lead and cadmium levels in blood, kidney, liver, muscle, salt glands, breast feathers, and bone. In control birds lead levels were highest in bone, feathers, salt gland, and kidney, and lowest in blood, muscle, and brain. In experimental birds lead levels were highest in bone, liver, kidney, and feathers, and lowest in blood, muscle, and salt gland. In control birds cadmium levels were highest in the kidney, followed by liver, with blood and brain being the lowest. Lead-exposed birds had increased cadmium deposition in brain. For experimental birds lead levels were correlated for all tissues except the salt gland. Correlations were particularly high for feathers with brain, kidney, liver and bone, suggesting feathers can be used in biomonitoring of natural avian populations. For cadmium there were no significant correlations among tissue levels except for brain and liver. Bioamplification of lead was greatest for liver and blood, and lowest for muscle and salt gland when comparing a lead dose of 0.1 mg/g with controls.

Factors affecting tissue distribution of heavy metals : Age effects and the metal concentration patterns in common terns,Sterna hirundo

Metal distribution in an organism at any one time is a resultant of many extrinsic and intrinsic factors. Improved analytic methodology has made it feasible to obtain highly sensitive determinations for many metals in a single sample. Thus, it is now feasible to examine patterns of metal distribution. We report on a study of the effect of age on metal patterns in the common tern,Sterna hirundo, a fisheating seabird. We contrast the levels of nine metals in the liver of adult and young terns and compared these with levels in tern eggs. Unlike many previous studies, adults did not have significantly higher levels of metals, although for most metals, levels in eggs were significantly lower than liver levels of young and adults. The intermetal correlations showed more significant positive correlations for adults and eggs than for chicks, the latter showing instead a correlational chaos, probably reflecting the immaturity of their physiologic defense mechanisms and the absence of dynamic equilibrium.

Heavy metal concentrations in the liver of three duck species: influence of species and sex

To investigate interspecific and intersex differences in heavy metal levels, we analysed concentrations of cadmium, cobalt, chromium, copper, lead, mercury, manganese, nickel and zinc in the livers of male and female black duck (Anas rubripes), mallard (A. platyrhynchos) and greater scaup (Aythya marila) collected in Raritan Bay, New Jersey in December 1980 and January 1981. Certain metal levels varied significantly by species and sex. In all species, Zn and Cu had the highest concentrations, and Cd, Co, and Hg were lowest in all three species. Scaup had significantly higher levels of Cu than black ducks and mallards, and mallards had significantly higher levels of Mn and Zn than black duck and scaup. Overall, eight of nine metal levels were higher in male than female black duck. In scaup, females had significantly higher levels of Pb and Mn than males. In black ducks, males had significantly higher levels of Cu, Mn and Zn than females. The sample of mallard was too small to test intersex differences.

Comparisons of nine heavy metals in salt gland and liver of greater scaup (Aythya marila), black duck (Anas rubripes) and mallard (A. platyrhynchos)

Levels of nine heavy metals were measured in the livers and salt glands of greater scaup (Aythya marila), black duck (Anas rubripes) and mallard (A. platyrhynchos) from Raritan Bay, New Jersey to determine if the functioning avian salt gland concentrates heavy metals. Heavy metals examined were cadmium, cobalt, chromium, copper, lead, mercury, manganese, nickel and zinc. Heavy metal levels varied significantly by species and tissue for chromium, copper, lead, and manganese, and by tissue for cobalt, mercury, nickel and zinc. In comparing tissues cobalt was higher in the salt glands than in livers of all three species; chromium and nickel were higher in the salt gland than liver for mallard and black duck; and lead, manganese and zinc were higher in the liver than the salt gland in greater scaup. Generally metal levels were higher in the salt gland for mallard and black duck, and in the liver for greater scaup.

Trace metal changes associated with age of marine vertebrates

Concentrations of selected trace metals in feral populations of marine and coastal elasmobranchs, teleosts, birds, and pinniped mammals are clearly related to age. Regardless of species or tissues, all data for individual metals, except Mn, showed the following trends: increases in Cd, Pb, Hg, and Se with increasing age of the organism; and decreases in Cr, Cu, Fe, Ni, and Zn. For Mn, mammals showed an increase with age whereas birds and fish exhibited decreases. The biological implications of these observations are imperfectly understood at this time. Factors that may account, in part, for these trends include differential uptake at various life stages, reproductive cycle, diet, general health, bioavailability of different chemical species, metal-metal interactions, metallothioneins, critical body parts, and anthropogenic influences.

Bioaccumulation of lead and cadmium in the Royal Tern and Sandwich Tern

Lead and cadmium concentrations were measured in eggs and tissues of downy young, prefledgling, and adult Royal and Sandwich Terns collected from Galveston Bay, Texas. These species do not differ significantly in the amount of heavy metals they accumulate; however, they differed from other species of the same trophic level from Galveston Bay in degree and pattern of temporal accumulations of these metals. Lead levels were lower in terns, but cadmium levels in adult terns were higher than those of other species. The prefledglings of other species at this trophic level have lead and cadmium concentrations which are similar to those found in adults. In contrast, the concentrations of the metals in adult terns are markedly higher than those found in prefledgling terns. This suggests that accumulation of metals continues as the birds age.