Liver Pb Concentrations Research Articles

Trace elements in liver and muscle tissues from wild waterfowls in Australia: Risk associated with human consumption in a global context

Trace elements in game meats remain a point of concern for both the public and policymakers alike due to the human health implications if levels present are above guideline limits. This study aimed to: (1) determine trace element concentrations (As, Cd, Hg, Pb Cr, Cu, Se, Zn) in edible portions (breast meat and liver) of the four most frequently hunted duck Anatidae species inhabiting wetlands in Victoria, Australia, to identify the risk to human health from consumption; (2) investigate landscape-scale variables that may influence the detected concentrations and; (3) review the studies available (n = 41) in duck liver and muscle tissues from the 1970s to 2024, to contextualise the detected concentrations found on a global scale. Our study shows that ducks in Victoria had trace element concentrations below tolerable daily intake (TDI) guidelines for human health with one exception: notably high Hg in a filter-feeding specialist, the Pink-eared duck (Malacorhynchus membranaceus). Yet, the only trace element concentrations that were influenced by proximity to populated centres, were As and Zn. Compared to international reports, Pb concentrations in livers and muscle of Victorian waterfowl were lower, however, Pink-eared ducks had higher Hg than other duck (Anas spp.) species. Review of the worldwide data indicate that Pb concentrations in liver tissues from all Anas species have declined from the 1970s to 2024. This is the first study to identify this trend at a global scale. International movements towards Pb-shot bans, along with phasing out of Pb in gasoline and paint are the most likely cause of declining concentrations in tissues of wild waterfowl. These findings strongly underscore the importance of legislative efforts to limit trace elements entering the environment.

Assessment of Hepatic Mineral Composition in Sheep, Cattle, Chicken, and Fish in Erbil City, Kurdistan Region-Iraq

Liver mineral concentrations of 232 samples from slaughtered animals, including lamb, yearling, sheep, and cattle, checkin, and fish were detrmined, using X-ray fluorescence spectrometer, to provide data regarding to the liver mineral concentrations (mg/kg dry weight). The mean liver Zn and Co liver conentrations of lambs (286, 1.9), yearling (233, 1.7), sheep (254, 1.8), and cattle (276, 1.8) in majority samples were adequate, while liver Pb concentrations of mentioned animals (45.3, 48.1, 46.4, 39.6) mg/kg respectively were high and exceeded toxic levels. In checkin, the mean liver Cu, Zn, and Co were also adequate, with the mean values of (26.4), (298.8), and (1.8) mg/kg respectively. Though, the mean liver Fe concentration (2257.0 mg/kg) was high, and liver Pb concentration (6.2 mg/kg) was reched toxic level. In fish, for majority liver samples, the mean concentration of Cu (191.8), Fe (6800.0), Zn (202.8), Co (3.3), Pb (8.6), and Ni (6.3) were high and toxic. In conclusion, liver Pb (and Ni only in fish) concentration in all studied animals for the majority of examined sample were higher than normal and toxic. Wherese, other studied minerals in majority of liver samples were adequate. Therefore, it can be concluded that there are problems on animal and human health (due to high concentration of Pb and Ni) would be raised at present from the consumption of ovine, bovine, checkin, and fish slaughtered from the city of Erbil.

Heavy metals in livers of raptors from Eastern Poland – the importance of diet composition

Concentrations of Pb, Cd, Ni, Cr and Hg were determined in livers of six species of raptors collected in the area of Eastern Poland. Redundancy analysis (RDA) showed that elevated Hg and Cr concentrations were directly related to feeding on passerines. Raptors that specialised in seizing small mammals as a source of food revealed higher hepatic concentrations of Pb and Cd in comparison with other raptors. Unlike Cd, we found statistically significant differences in the Pb concentrations in livers of Common buzzards as compared to Sparrowhawks. In spite of the fact that both Goshawks and Sparrowhawks hunt birds, only the latter species had accumulated significantly more mercury. The high concentrations of Hg in Sparrowhawks could be related to the use of mercury in antifungal substances for seed dressing.

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.

Mucous cell responses to contaminants and parasites in shorthorn sculpins (Myoxocephalus scorpius) from a former lead‑zinc mine in West Greenland

Previous studies of sculpins from the former lead (Pb) - zinc (Zn) mine near Maarmorilik, West Greenland, have shown that these fish are affected by heavy metal exposure from the mine. In this study, we applied mucosal mapping (a stereological method for mucosal quantification in fish) to uncover interactions between the host, parasites and heavy metal exposure (Pb and Zn) in shorthorn sculpins from the Maarmorilik mining site at a gradient of 3 stations. Skin and gill mucosal epithelia of shorthorn sculpins were significantly affected and reflected the exposure to environmental heavy metals and parasites. Size of skin mucous cells was significantly smallest in the sculpin from the station 3 where heavy metal contamination was lowest and the skin parasite load was highest. Gill filament mucous cells were largest and densest in fish from station 1 which was the most contaminated site. In gill lamellae the density of mucous cell followed a toxicity gradient and was significantly highest at the most contaminated station and significantly lowest at the least contaminated station. The persistent presence of toxic Pb and Zn levels in the sediment at the most contaminated station may have induced a small but measurable reduction in the surface area available for respiration and may have affected diffusion distance. The strong correlation between size of filamentous mucous cells and Pb concentrations in liver suggests that these cells can play an active role in reducing the somatic load of Pb in sculpin. We suggest that mucosal mapping can be used to assess effects of contaminant and parasite exposure in future environmental field studies.

Habitat use strategy influences the tissue signature of trace elements including rare earth elements in an urban-adapted omnivorous bird

Concentrations of trace elements vary naturally between geological environments and as a result of emissions from anthropogenic activities. Habitat use strategy is an important determinant of trace element concentrations in tissues and eggs of wild birds. However, a scarcity of studies have documented the relationships between individual bird movements related to foraging activities and exposure to contaminants including trace elements. The objective of the present study was to investigate the influence of habitat use strategy, determined using GPS-based telemetry, on the liver concentrations of selected trace elements including rare earth elements (REEs) as well as lead (Pb) isotope ratios in an urban-adapted omnivorous bird, the ring-billed gull (Larus delawarensis). Male (n = 20) and female (n = 18) ring-billed gulls breeding near Montreal (QC, Canada) in one of the largest colony in North America were tracked using miniature GPS devices to characterize their movements over a 10-days period. The time spent foraging by both male and female gulls in landfills and wastewater basins positively correlated with liver Pb concentrations. A positive correlation was also found between the time spent foraging in agricultural fields and liver concentrations of yttrium (Y) in male and female ring-billed gulls. Heavy REE concentrations were significantly greater in female gull liver relative to those of males, although this was not associated with the time spent in any foraging habitats. Pb isotope ratios (208Pb/206Pb and 206Pb/207Pb) in the liver of male ring-billed gulls tended to be lower in individuals that foraged in landfills, thus indicating that they may have been exposed to different Pb sources relative to birds that visited other sites. This study provided valuable information on the potential sources of trace elements at the landscape level in free-ranging birds spanning urbanized environments.

CONCENTRATION OF SELECTED HEAVY METALS IN BROWN HARE (LEPUS EUROPAEUS) AND WILD BOAR (SUS SCROFA) FROM CENTRAL TURKEY

In the present study, concentrations of heavy metals viz. chromium (Cr), manganese (Mn), copper (Cu), zinc (Zn), cadmium (Cd), mercury (Hg), lead (Pb), and a metalloid selenium (Se) were examined in kidney, liver and muscle tissues of 15 brown hares ( Lepus europaeus ) and 9 wild boars ( Sus scrofa ) obtained from Kirikkale province located in central Turkey. Significant variation in the concentrations of the studied heavy metals in the selected tissues was recorded. Mean concentrations of Cr (1.02 mg/kg), Mn (6.00 mg/kg), Se (1.15 mg/kg) and Cd (4.49 mg/kg) were the highest in hare kidney compared to other tissues, whereas concentrations of Cu (2.34 mg/kg) and Zn (40.51 mg/kg) were the highest in hare liver, and Pb (7.83 mg/kg) was the highest in hare muscle. On the other hand, mean concentrations of Cr (1.82 mg/kg), Cu (1.25 mg/kg), Se (3.55 mg/kg) and Cd (3.05 mg/kg) were the highest in boar kidney compared to liver and muscle tissues, whereas concentrations of Mn (3.89 mg/kg) and Pb (0.75 mg/kg) were the highest in boar liver, and Zn (45.65 mg/kg) was the highest in boar muscle. Strong positive significant correlations were found between Cr and Hg, and between Cu and Pb concentrations in kidney in all wild boar samples. There were also strong positive significant correlations between Cd and Pb concentrations in liver and Cd and Pb concentrations in muscle in all hare samples. Our results revealed that Hg (1/9 boar kidney; 4/15 hare kidney), Cr (9/9 boar all three tissues; 9/15 hare kidney and 11/15 hare liver), Pb (4/9 boar muscle; 5/15 hare liver, 15/15 hare muscle) and Cd (9/9 boar all three tissues; 15/15 hare all three tissues) concentrations detected in wild boar and hare tissues in the present study were higher than the hygienic limits.

Concentration of heavy metals (Pb, Cd) in muscle and liver of Perca fluviatilis and Tinca tinca in Anzali Wetland, southwest the Caspian Sea

Anzali Wetland is one of the most important aquatic ecosystems of Iran located at southwest of the Caspian Sea. This wetland is a habitat for valuable fish with vital role in life cycle of this ecosystem. Assessment of pollutants concentration is rational due to complications of determining biological effects in a habitat. The present study examined the concentration of lead (Pb) and cadmium (Cd) in muscles and livers of two fish species i.e. Perca fluviatilis and Tinca tinca collected from Anzali Wetland, and their relationships with fish size (length and weight). The results showed the highest concentration of metals in liver, and the lowest in muscle tissues of both species. Highest concentrations of Cd (0.09) and Pb (3.66) were recorded in liver tissue of T. tinca . The results also showed significant negative correlation between metal concentrations and fish size. Highly significant (P<0.01) negative relationships were observed between fish length and Pb concentrations in liver of P. fluviatilis . Cd and Pb concentrations in liver of P. fluviatilis and Cd concentrations in the liver of T. tinca showed significant negative relationships (P<0.05) with size factors. The concentrations of Pb and Cd were lower than the maximum acceptable concentrations for fish proposed by MAFF thus safe for human utilization.

Comparison of trace element concentrations in grey heron and black-crowned night heron chicks.

Cadmium (Cd), lead (Pb), manganese (Mn), zinc (Zn), and iron (Fe) concentrations were measured in the prey and liver of grey heron (Ardea cinerea) and black-crowned night heron (Nycticorax nycticorax) chicks (24-26 days after hatching) at the Pyeongtaek colony, Korea in 2001 (n = 10, respectively) and 2008 (n = 11 and n = 10). Cadmium and Pb concentrations in livers of grey heron (Cd geomean 0.06, Pb 3.90 μg/g dw) and black-crowned night heron (Cd 0.20, Pb 4.24 μg/g dw) chicks were increased with diet concentrations of grey heron (Cd 0.18, Pb 1.76 μg/g dw) and black-crowned night heron (Cd 0.20, Pb 3.96 μg/g dw) chicks. Cadmium and Pb concentrations in prey items of grey heron and black-crowned night heron chicks were a good predictor of chick liver concentrations. Cadmium concentrations in livers of both heron species collected at the Pyeongtaek heronry were relatively low and within the background level (<3 μg/g dw) for birds. Five of 20 (25.0%) grey heron and 4 of 18 (22.2%) black-crowned night heron chicks were higher than the background level for lead (>6 μg/g dw). Prey Cd and Pb concentrations were within the range of other heron and egret studies. Manganese, Zn, and Fe concentrations in grey heron and black-crowned night heron chicks were within the background or normal physiological levels reported earlier in other birds including herons and egrets.

Beavers indicate metal pollution away from industrial centers in northeastern Poland.

Heavy metals are persistent environmental contaminants, and wild animals are increasingly exposed to the harmful effects of compounds of anthropogenic origin, even in areas distant from industrial centers. We used atomic absorption spectrometry to determine levels of cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn) in liver and kidney of wild Eurasian beavers (Castor fiber) in Poland. Cd concentrations in liver (0.21 ± 0.44 μg/g) and in kidney (2.81 ± 4.52 μg/g) were lower in juvenile than in adult beavers. Pb concentrations in liver (0.08 ± 0.03 μg/g) and kidney (0.08 ± 0.03 μg/g) were similar among all individuals, while both Cu and Zn levels were higher in liver (Cu 9.2 ± 4.5 μg/g; Zn 35.7 ± 3.5 μg/g) than in kidney (Cu 3.7 ± 1.1 μg/g; Zn 21.5 ± 2.7 μg/g). Cu levels also differed between juveniles and adults. We reviewed the literature reporting metal concentrations in beavers. Our results indicate metal contamination in beavers away from important industrial emission sources and suggest the natural environment should be regularly monitored to ensure their levels are below recommended, legal values.

Impact of trace metals from past mining on the aquatic ecosystem: A multi-proxy approach in the Morvan (France)

This study seeks to determine to what extent trace metals resulting from past mining activities are transferred to the aquatic ecosystem, and whether such trace metals still exert deleterious effects on biota. Concentrations of Cd, Cu, Pb and Zn were measured in streambed sediments, transplanted bryophytes and wild brown trout. This study was conducted at two scales: (i) the entire Morvan Regional Nature Park and (ii) three small watersheds selected for their degree of contamination, based on the presence or absence of past mining sites. The overall quality of streambed sediments was assessed using Sediment Quality Indices (SQIs). According to these standard guidelines, more than 96% of the sediments sampled should not represent a threat to biota. Nonetheless, in watersheds where past mining occurred, SQIs are significantly lower. Transplanted bryophytes at these sites consistently present higher trace metal concentrations. For wild brown trout, the scaled mass and liver indices appear to be negatively correlated with liver Pb concentrations, but there are no obvious relationships between past mining and liver metal concentrations or the developmental instability of specimens. Although the impact of past mining and metallurgical works is apparently not as strong as that usually observed in modern mining sites, it is still traceable. For this reason, past mining sites should be monitored, particularly in protected areas erroneously thought to be free of anthropogenic contamination.

Reducing Pb poisoning in birds and Pb exposure in game meat consumers: The dual benefit of effective Pb shot regulation

The use of lead (Pb) ammunition in the form of shot pellets has been identified as a Pb exposure risk in wildlife and their human consumers. We explore the hypothesis that Pb shot ban enforcement reduces the risk of avian Pb poisoning as well as Pb exposure in game meat consumers. We assessed compliance with a partial ban on Pb shot commencing in 2003 by examination of 937 waterbirds harvested by hunters between 2007 and 2012 in the Ebro delta (Spain). Prevalence of Pb shot ingestion was determined, as were Pb concentrations in liver and muscle tissue to evaluate the potential for Pb exposure in game meat consumers. Hunted birds with only embedded Pb shot (no steel) declined from 26.9% in 2007–08 to <2% over the following three hunting seasons after ban reinforcement. Pb shot ingestion in mallards decreased from a pre-ban value of 30.2% to 15.5% in the post-ban period. Liver Pb levels were predominantly defined by the presence of ingested shot, whereas muscle levels were defined by the presence of both ingested and embedded shot. Only 2.5% of mallard muscle tissue had Pb levels above European Union regulations for meat (0.1μg/g wet weight) in the 2008–09 season, when Pb shot ingestion prevalence was also at a minimum (5.1%). Effective restrictions in Pb ammunition use have a dual benefit since this reduces Pb exposure for game meat consumers due to embedded ammunition as well as reducing Pb poisoning in waterbirds.

Noninvasive heavy metal pollution assessment by means of Iberian wolf (Canis lupus signatus) hair from Galicia (NW Spain): a comparison with invasive samples

The current study represents the first investigation of the suitability of wolf hair as indicator tissue for metal exposure and accumulation within NW Spanish ecosystems. Dead animals, which were not specifically killed for these purposes, were necropsied, and further toxicological analyses were performed in order to establish the heavy metal content (Pb, Cd, and Zn) in liver, kidney, and hair, by means of inductively coupled plasma optical emission spectrometry. Two different factors, gender and age, were considered in order to determine their influence on heavy metal accumulation. Mean liver, kidney and hair concentrations of both toxic element, Cd (0.528, 2.692, and 0.026 ppm) and Pb (4.108, 0.031, and 0.196 ppm) considered on a dry weight basis, were situated below the established as acute toxicity levels for mammals. The highest concentrations were quantified for Zn, with means ranging from a maximum in hair samples (150.9 ppm) to a minimum in kidney samples (25.81 ppm). When the variable of gender and age were considered, female and adult wolves had higher concentrations of Cd in all the considered organs, although differences were only statistically significant for kidney. Neither the sex nor the age had a significant effect on Pb and Zn concentrations. A significant positive correlation (p < 0.05) was identified between hair and liver Pb concentrations, as well as between hair and kidney Cd concentrations, thus suggesting the interest of the noninvasive sample for future ecotoxicological biomonitoring studies.

Toxic Exposure of Songbirds to Lead in the Southeast Missouri Lead Mining District

Mining and smelting in the Southeast Missouri Lead Mining District has caused widespread contamination of soils with lead (Pb) and other metals. Soils from three study sites sampled in the district contained from approximately 1,000-3,200 mg Pb/kg. Analyses of earthworms [33-4,600 mg Pb/kg dry weight (dw)] collected in the district showed likely high Pb exposure of songbirds preying on soil organisms. Mean tissue Pb concentrations in songbirds collected from the contaminated sites were greater (p < 0.05) than those in songbirds from reference sites by factors of 8 in blood, 13 in liver, and 23 in kidney. Ranges of Pb concentrations in livers (mg Pb/kg dw) were as follows: northern cardinal (Cardinalis cardinalis) = 0.11-3.0 (reference) and 1.3-30 (contaminated) and American robin (Turdus migratorius) = 0.43-8.5 (reference) and 7.6-72 (contaminated). Of 34 adult and juvenile songbirds collected from contaminated sites, 11 (32%) had hepatic Pb concentrations that were consistent with adverse physiological effects, 3 (9%) with systemic toxic effects, and 4 (12%) with life-threatening toxic effects. Acid-fast renal intranuclear inclusion bodies, which are indicative of Pb poisoning, were detected in kidneys of two robins that had the greatest renal Pb concentrations (952 and 1,030 mg/kg dw). Mean activity of the enzyme delta-aminolevulinic acid dehydratase (ALAD) in red blood cells, a well-established bioindicator of Pb poisoning in birds, was decreased by 58-82% in songbirds from the mining sites. We conclude that habitats within the mining district with soil Pb concentrations of ≥1,000 mg Pb/kg are contaminated to the extent that they are exposing ground-feeding songbirds to toxic concentrations of Pb.

Concentration of heavy metals in tissues of green turtles (Chelonia mydas) sampled in the Cananéia estuary, Brazil

Thirty specimens (15 adults and 15 juveniles) of Chelonia mydas found in the Cananéia estuary in the state of São Paulo on the southeastern Brazilian coast between January 2005 and September 2006, were analyzed The concentrations of Cd, Cu, Pb, Mn and Ni in liver and kidney samples of adult and juvenile green turtles were determined by Flame Atomic Absorption Spectrophotometry.The average Cd concentration found in adult livers (0.57µg.g-1) was significantly higher than that in juveniles (0.279µg.g-1). Cu concentrations were significantly higher in the liver than in the kidney, and significantly higher in adults (39.9µg.g-1) than in juveniles (20.7µg.g-1) Average Mn concentrations in liver and kidney did not differ between adults (4.32 and 4.17µg.g-1) and juveniles (4.81 and 3.82µg.g-1), whereas Ni concentrations in adults (0.28 and 0.19µg.g-1, respectively) were significantly higher than in juveniles (0.13 and 0.089µg.g-1, respectively). Pb concentrations in liver were significantly higher in adults (0.37µg.g-1) than in juveniles (0.06µg.g-1). The concentrations of essential trace elements in Chelonia mydas were generally comparable to values reported in other, similar studies. With respect to non-essential metals (Cd, Pb and Ni), Chelonia mydas presented lower values than those reported for their northern Atlantic counterparts.

Heavy metal exposure in large game from a lead mining area: Effects on oxidative stress and fatty acid composition in liver

The Pb mining area of the valley of Alcudia and the Sierra Madrona mountains (S. Spain) has been exploited intermittently for over 2100 years, since Roman occupation and up until the late 1900s. Red deer ( n = 168) and wild boar ( n = 58) liver and bone (metacarpus) were analyzed for Pb, Zn, Cu, Cd, As and Se. Lipid peroxidation, total and oxidized glutathione (GSH), superoxide dismutase (SOD), GSH peroxidase (GPX) and fatty acid composition were studied in liver of red deer. The concentrations of Pb in liver and bone of red deer and wild boar were higher in the mining area than in the control area, and higher in the wild boar than red deer, but well below the level associated with clinical signs of Pb poisoning. Liver levels of Cu, Cd and Se were also higher in red deer from the mining area. Red deer from the mining area had 39% less total GSH than in the control area. The percentage of docosahexaenoic acid in liver of red deer from the mining area was 16% lower than in the control area.

Lead contamination and associated disease in captive and reintroduced red kites Milvus milvus in England

Since 1989, a red kite Milvus milvus reintroduction programme has been underway in the United Kingdom, with 4-6 week old nestlings brought into captivity and held for 6-8 weeks before reintroduction. As scavengers, red kites may consume unretrieved game, and ingest shot or lead (Pb) fragments in their prey's flesh. We evaluated exposure to Pb in captive and wild red kites by taking blood samples from 125 captive young red kites prior to release, through analysing 264 pellets (regurgitated by wild birds) collected from under a roost site, and analysing Pb concentrations in livers and/or bones of 87 red kites found dead between 1995 and 2003. Lead isotope analyses of livers were also conducted in an effort to identify Pb exposure routes. Forty-six (36.8%) kites sampled prior to release had elevated blood Pb concentrations (201-3340 microg l(-1)). The source of this Pb was probably small fragments of lead ammunition in the carcasses of birds or mammals either fed to the nestlings by their parents or, more likely, subsequently whilst in captivity. Once released, kites were also exposed to lead shot in their food, and a minimum of 1.5-2.3% of regurgitated pellets contained Pb gunshot. Seven of 44 red kites found dead or that were captured sick and died within a few days had elevated (>6 mg kg(-1) dry weight [d.w.]) liver Pb concentrations, and six of these (14%) had concentrations of >15 mg kg(-1) d.w., compatible with fatal Pb poisoning. Post-mortem analyses indicated that two of these birds had died of other causes (poisoning by rodenticide and a banned agricultural pesticide); the remaining four (9%) probably died of Pb poisoning. Bone samples from 86 red kites showed a skewed distribution of Pb concentration, and 18 samples (21%) had Pb concentrations >20 mg kg(-1) d.w., indicating elevated exposure to Pb at some stage in the birds' life. Lead isotopic signatures (Pb (208/206); Pb (206/207)) in liver samples of the majority of kites were compatible with those found in lead shot extracted from regurgitated pellets. Lead isotope ratios found in the livers of kites with very low Pb concentrations were distinct from UK petrol Pb isotopic signatures, indicating that birds were exposed to little residual petrol Pb. We conclude that the primary source of Pb to which red kites are exposed is lead ammunition (shotgun pellets or rifle bullets), or fragments thereof, in their food sources; in some cases exposure appears sufficient to be fatal. We make recommendations to reduce Pb poisoning in both captive and wild red kites and other scavenging species.

Metal concentrations in selected organs and tissues of five Red-knobbed Coot (&lt;i&gt;Fulica cristata&lt;/i&gt;) populations

The Red-knobbed Coot Fulica cristata is an abundant aquatic bird in South Africa and was anticipated to have indicator abilities for metal pollution. This hypothesis was tested on 83 coot samples collected from five selected aquatic ecosystem areas supporting substantial coot populations, of which various abiotic and biotic components are known to contain varying levels of a number of metals. The aim of this study was achieved by determining the variations in Cd, Cu, Ni and Pb concentrations in liver, kidney, bone and blood samples, with the use of standard flame atomic absorption spectrophotometry techniques. Coots from the Germiston Lake sampling site showed the highest concentrations of cadmium in liver (2.2 µg/g d.w.) and kidney (5.4 µg/g d.w.). The absence of metalprocessing industries in the catchments of the Florida Lake and the Steynsrus farm dams reflects the low liver and kidney concentrations of Cd, Ni and Cu, respectively. The blood of the Natalspruit wetland coots contained the highest dry weight concentrations of Ni (11.4 µg/g), Cd (1.8 µg/g) and Cu (14.4 µg/g). The statistical evaluation points towards small-scale geographical differences, especially in the concentrations of Cu, Ni and Pb and in the liver, kidney and blood. However, in terms of actual metal concentrations recorded, no significant differences existed between coots of the reference site (Steynsrus farm dams) and those from the other four localities. It is concluded that the impact of metal-containing diets on the tissue concentrations of these metals in birds plays a far more significant role compared to the migratory habits or short-range movements of the coots.

The route of transfer to the human population of lead from contaminated soil close to a smelter in Bulgaria

Past emissions from a non-ferrous smelter at Kuklen, near Plovdiv, in Bulgaria have resulted in very high concentrations of heavy metals, in particular Cd and Pb, in agricultural soils close to the plant. An interdisciplinary research project, initiated under the auspices of the EU INCO-Copernicus programme, has included investigation of the principal processes by which the heavy metals are being transferred from the contaminated soils to the children of the village who have abnormally high Cd and Pb blood concentrations. The primary source of Pb in blood is the land close to the smelter which has elevated concentrations of Pb and which is used to grow food and fodder for livestock. Fodder with Pb concentrations as high as 48 mg/kg is consumed directly by the animals resulting in high Pb concentrations in livers and kidneys. These are then consumed by the human population. The evidence clearly indicates this to be one route of transfer through the food chain. Other, more direct, routes, e.g the use of flour prepared from locally produced grain or the direct ingestion of dust from school playgrounds, the street and homes, may also play an important role.

Heavy Metal Concentrations in Tissues of Feral Pigeons(Columba livia) from Urban Areas in Korea

The present study was to investigate Pb and Cd concentrations in tissues of feral pigeons in urban areas. The Pb levels in bones and livers did not differ between Seoul and Kwangju areas. However, there were significant differences in kidney and liver Cd concentrations between the study sites. These are thought to be a reflection of the metal exposure conditions in the local environment. In particular, metal levels from Seoul were compared with those obtained in the same area between 1991 and 2000 in terms of the long-term biomonitoring approaches. The mean Pb concentrations in bones decreased from 59.1 <TEX>$\mu$</TEX>g/wet g in 1991 to 29.5 <TEX>$\mu$</TEX>g/wet g in 2000, totaling a reduction in concentrations of approximately 50 percent. However, there were no significant differences in the liver Pb concentrations. Concentrations of Cd in livers and kidneys did not differ between 1991 and 2000.