Pb Shot Ingestion Research Articles

Risk assessment of lead poisoning and pesticide exposure in the declining population of red-breasted goose (Branta ruficollis) wintering in Eastern Europe

The red-breasted goose Branta ruficollis is a globally threatened species (IUCN Vulnerable) and the only European goose species currently in decline. Working on the wintering grounds on the Black Sea Coast, we address two potential causes of decline of this species for the first time: lead poisoning, and contamination from pesticides. We quantified the densities of spent Pb shot in three wetlands used by the geese in north-east Bulgaria, and analysed the Pb concentration in the faeces of red-breasted geese and the more abundant greater white-fronted geese Anser albifrons, using Al concentration as an indicator of soil ingestion. Pb shot densities in sediments were low, and we found no evidence for Pb shot ingestion in red-breasted geese. On the other hand, we found that the geese were feeding on wheat whose seeds were treated with four fungicides: thiram, tebuconazole, difenoconazole and fludioxonil, and the two first were even detected in geese faecal samples. Using data on the daily food intake, we estimated the exposure levels of the geese to these fungicides, both by measuring the concentrations remaining on seeds and by estimating the amount used to coat the seeds at the time of sowing. We found that the exposure rates estimated during the sowing period for both geese species can exceed the recognized hazardous doses for thiram, and to a lesser extent for tebuconazole, which indicates that some pesticides may be playing a previously overlooked role in the decline of red-breasted geese.

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 (6-30µg/gdw). 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 (<3µg/gdw) for wild birds.

Altered immune response in mallard ducklings exposed to lead through maternal transfer in the wild

Lead (Pb) poisoning has caused significant mortality in waterfowl populations worldwide. In spite of having been banned since 2003, prevalence of Pb shot ingestion in mallards (Anas platyrhynchos) from the Ebro delta was still 15.5% in 2011–12. We collected mallard eggs from this area to study the effects of maternally transferred Pb on eggshell properties and on immune response and oxidative balance of ducklings. Eggshell Pb levels were positively correlated with Pb levels in the blood of ducklings. Ducklings with blood Pb levels above 180 ng mL−1 showed reduced body mass and died during the first week post hatching. Blood Pb levels positively correlated with humoral immune response, endogenous antioxidants and oxidative stress biomarkers, and negatively correlated with cellular immune response. Pb shot ingestion in birds can result in maternal transfer to the offspring that can affect their developing immune system and reduce their survival in early life stages.

Lesser White-fronted (Anser erythropus) and Greater White-fronted (A. albifrons) Geese wintering in Greek wetlands are not threatened by Pb through shot ingestion

Fecal lead (Pb) levels were investigated in the threatened European population of the Lesser White-fronted Goose (LWfG, Anser erythropus) and of the non-threatened Greater White-fronted Goose (GWfG, Anser albifrons) wintering in two wetland areas in northern Greece in order to assess the potential risk from Pb exposure. Fecal, soil and food plant samples were analyzed. Levels of Pb were normalized using Al concentrations in order to separate the effect of possible ingestion of Pb shot from that of soil or sediment accidentally ingested with food. All concentrations are expressed on a dry weight basis. Geometric means of Pb content in the feces of LWfG were 6.24mg/kg at Evros Delta and 7.34mg/kg at Lake Kerkini (maximum values of 28.61mg/kg and 36.68mg/kg, respectively); for fecal samples of GWfG geometric means were 2.39mg/kg at Evros Delta and 6.90mg/kg at Kerkini (corresponding maximum values of 25.09mg/kg and 42.26mg/kg). Soil Pb was in the range of 5.2–60.2mg/kg (geometric mean=22.6mg/kg) for the Evros Delta and between 13.4 and 64.9mg/kg (geometric mean=28.1mg/kg) for Kerkini.A general linear model fitted to the data showed that Pb levels were very closely dependent on Al levels in the feces from both species and at both sites indicating soil or sediment were the only significant source of Pb; species and site, as well as their interaction, were not statistically significant factors. For both species and at both sites exposure to Pb was evidently very mild and the observed levels of Pb were well below the proposed thresholds for lethal or sublethal effects of Pb poisoning. Soil ingestion appeared to gradually increase from October to December for LWfG at Kerkini, corresponding to a gradual depletion of their food source.

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.

Identifying Sources of Pb Exposure in Waterbirds and Effects on Porphyrin Metabolism Using Noninvasive Fecal Sampling

Waterbird feces (mainly mallard Anas platyrhynchos and coot Fulica atra) were collected from four wetlands in Southern Spain in the field or during capture (n = 558 and n = 59, respectively) to study lead (Pb) shot ingestion. Lead and aluminum (Al) concentrations along with Pb isotope signatures were used to identify sources of Pb exposure. The profile and concentrations of porphyrins and biliverdin in feces were used as biomarkers of toxicological effects. Feces with Pb concentrations ≥ 34 μg/g d.w. showed higher Pb/Al ratios, together with lower (206)Pb/(207)Pb and (208)Pb/(207)Pb ratios, and higher (208)Pb/(206)Pb ratios, than feces with <34 μg/g d.w. Isotope signatures and Pb/Al ratios together indicated that Pb shot ingestion was the likely cause of the high Pb levels in some samples, whereas sediment ingestion was linked to lower/background levels. Coproporphyrin I and protoporphyrin IX were also higher in feces with Pb ≥ 34 μg/g d.w., indicating measurable disruption in heme synthesis. Noninvasive fecal sampling permits study of the degree and source of Pb exposure and physiological effects, with low-effort and minimal disturbance to waterbirds.

Pb–Al relationships in waterfowl feces discriminate between sources of Pb exposure

Hunted mallards ( n = 56) were collected in the Ebro Delta (Spain) in 2007–08 to evaluate the use of feces as a non-invasive monitoring method to study lead shot ingestion. The prevalence of Pb shot ingestion in these birds was 28.6%, and similar to that reported before a ban on Pb shot use in 2003. Lead concentrations in terminal intestinal contents were higher in mallards with Pb shot in their gizzard. Feces Pb concentrations >34 μg/g d.w were indicative of Pb shot ingestion, and background Pb levels were <12.5 μg/g d.w. To discriminate between birds ingesting soil Pb, and those ingesting Pb shot, we correlated Al and Pb levels and showed that mallards with ingested Pb shot in the gizzard stood out as outliers within the regression. Feces Pb–Al relationships can be used as a simple non-invasive tool in monitoring programs regarding Pb shot ingestion in birds.

Trace Element Concentrations (Mercury, Cadmium, Copper, Zinc, Lead, Aluminium, Nickel, Arsenic, and Selenium) in Some Aquatic Birds of the Southwest Atlantic Coast of France

Trace elements (mercury [Hg], cadmium [Cd], copper [Cu], zinc [Zn], lead [Pb], aluminium [Al], nickel [Ni], arsenic [As], and selenium [Se]) were investigated using inductively coupled plasma-mass spectrometry in liver, kidney, muscle, and feather of aquatic birds wintering or inhabiting the wetlands situated on the Southwest Atlantic coast of France. A majority of greylag geese, red knots, and grey plovers were collected from among hunter-shot animals. The relation between residue concentrations, age (juvenile vs. adult), and sex was investigated. Trace elements were lower than threshold levels of toxicity, except for Pb. Greylag geese sampled could be considered Pb-poisoned. These consequential levels of contamination could be the result of the ingestion of Pb-shot from ammunition used in hunting areas they crossed during migration. Cd accumulation increased with age, whereas Pb levels in feathers were lower in adult birds in connection with moulting. As was influenced by sex. Female birds displayed higher concentrations in liver and feathers than did male birds.

Metal levels in the bones and livers of globally threatened marbled teal and white-headed duck from El Hondo, Spain

El Hondo is a key area for marbled teal and white-headed duck. We present Pb, Cu, Zn, Se, and As data for bone and liver in birds found dead between 1996 and 2001. Several metals were higher in adult white-headed ducks than in marbled teal. They were higher in female than in male white-headed ducks, and did not differ with sex in marbled teal, but did by age. Lead in liver of adults was influenced by Pb shot ingestion, which was detected in 21% of marbled teal and in 71% of white-headed duck. No marbled teal had liver levels indicative of Pb poisoning, while 86% of white-headed ducks did. Selenium, Zn, and Cu were elevated in 13%, 7%, and 39% of birds, respectively. Whilst Pb shot poses the greatest threat to these species, further work should assess exposure via plants, invertebrates, water, and sediments for other metals, and investigate possible sub-lethal effects.

Lead-Shot Exposure in Red-Legged Partridge (Alectoris rufa) on a Driven Shooting Estate

The goal of the study was to investigate the accumulation and spatial patterns of spent lead (Pb) shot pellets and the prevalence of shot ingestion in red-legged partridge in a driven shooting estate. Soil was collected using a regular sampling design perpendicular to three shooting lines. Factors involved in shot spatial distribution were investigated by a causal structural equation model (SEM). Shot ingestion prevalence and liver and bone Pb concentrations were studied in partridges hunted in 2004 and 2006. Shot soil-burden averaged 73,600 units/ha (i.e., 8.1 kg/ha). Shot density was significantly higher in front of than behind shooting lines, with greatest accumulation occurring at between 40-110 m and in certain ecotones (i.e., shrubland-dry cropland). Analyses revealed 7.8% of partridges with evidence of Pb shot ingestion. Particle size in diet, grit-size composition, and shot ingestion prevalence were significantly higher in 2004 than in 2006, indicating that supplying partridges with large seeds (i.e., corn) may increase the risk of Pb shot ingestion. Moving shooting lines into croplands and controlling seed size used for diet supplementation may reduce shot ingestion.

Heavy metals in livers of waterbirds from Spain.

Wetlands tend to accumulate heavy metals from local sources, such as Pb shot used for waterfowl hunting, and from regional sources, such as atmospheric deposition and riverine or marine inputs. We determined concentrations of six heavy metals (Cr, Mn, Cu, Zn, Cd, and Pb) in livers of waterbirds shot by hunters in five Spanish wetlands to study the different factors that can contribute to the accumulation of these metals (sex, age, diet, grit, and Pb shot ingestion). Differences among wetlands were observed only for Cr, Cu, and Cd. Differences among species were observed for all the metals, and Cu was notably higher in pochards (Aythya and Netta genus) than in other waterfowl. Cu, Zn, and Cd concentrations increased with age, and only Pb showed differences related to sex, with males having higher concentrations than females. Most metals other than Pb were correlated with each other. Lead was dependent on Pb shot ingestion. Grit ingestion positively correlated with concentrations of Cr and to a lesser extent with Mn, Zn, and Cd. Ingestion of grit or shot may obscure relationships between metals and diet. Herbivorous species, which had more grit in the gizzard, had higher Cr, Zn, and Cd concentrations. Granivorous birds, which have the highest rates of Pb shot ingestion, had the highest concentrations of Pb. Grit and Pb shot ingestion are both important sources of heavy metals for waterbirds. Lead was the single metal studied whose concentrations exceeded toxicity thresholds.

Lead poisoning in the globally threatened marbled teal and white‐headed duck in Spain

Marbled teal (Marmaronetta angustirostris) and white-headed duck (Oxyura leucocephala) are the two European ducks threatened with global extinction. We investigated lead (Pb) poisoning in stifftails (Oxyura spp., n = 83) and marbled teal (n = 80) shot or found dead or moribund in Spanish wetlands via gizzard examination and liver, bone, and blood Pb analysis. Ingested Pb shot was present in 32% of shot stifftails and 70 and 43% of dead or moribund stifftails and marbled teal, respectively. Lead-shot ingestion was more frequent in Valencia (eastern Spain), where Pb-shot densities were higher and grit scarcer. Selection of larger grit similar in size to Pb shot may explain the higher rate of Pb-shot ingestion observed in stifftails. Ingested shot was found more frequently in juvenile stifftails than in adults. Lead bone concentrations were higher in ducklings < 9 d old than in fully grown teal and were also higher in adult than in juvenile teal. Our results show the need for a ban of Pb shot for waterfowl hunting in Spain and the cleanup of spent shot at major wetlands.

Lead Shot Ingestion in Two Raptor Species from Doñana, Spain

Diurnal raptors inhabiting wetland areas where waterfowl shooting is conducted have many opportunities to ingest lead (Pb) shot pellets when feeding on their prey. Exposure to Pb shot was studied in the Spanish imperial eagle (Aquila adalberti), an endangered species with a world population of about 150 breeding pairs, and in the red kite (Milvus milvus) from Doñana (southwest Spain). Lead exposure was evaluated by the presence of Pb shot in the pellets of both species. Results obtained by this noninvasive method demonstrated Pb shot in 11.0% of Spanish imperial eagle and 5.5% of red kite pellets. When the data of both species were pooled, there was a significant relationship between Pb shot ingestion and consumption of waterfowl during the hunting season. Pb shot found in pellets exhibited signs of erosion, and their weight distribution had peaks at 70, 170, and 240 mg, which could correspond to ammunition used for duck and goose hunting.

LEAD POISONING IN THE GLOBALLY THREATENED MARBLED TEAL AND WHITE-HEADED DUCK IN SPAIN

Marbled teal (Marmaronetta angustirostris) and white-headed duck (Oxyura leucocephala) are the two European ducks threatened with global extinction. We investigated lead (Pb) poisoning in stifftails (Oxyura spp., n = 83) and marbled teal (n = 80) shot or found dead or moribund in Spanish wetlands via gizzard examination and liver, bone, and blood Pb analysis. Ingested Pb shot was present in 32% of shot stifftails and 70 and 43% of dead or moribund stifftails and marbled teal, respectively. Lead-shot ingestion was more frequent in Valencia (eastern Spain), where Pb-shot densities were higher and grit scarcer. Selection of larger grit similar in size to Pb shot may explain the higher rate of Pb-shot ingestion observed in stifftails. Ingested shot was found more frequently in juvenile stifftails than in adults. Lead bone concentrations were higher in ducklings <9 d old than in fully grown teal and were also higher in adult than in juvenile teal. Our results show the need for a ban of Pb shot for waterfowl hunting in Spain and the cleanup of spent shot at major wetlands.

Use of stable isotope ratios to distinguish sources of lead exposure in wild birds

We used stable lead (Pb) isotope ratios to attempt to discriminate between several potential sources of elevated environmental Pb exposure in several wild bird species. For juvenile herring gulls (Larus argentatus) from the Canadian Great Lakes, the mean 206Pb:207Pb ratio in bone (1.137 +/- 0.007) was within the range characterizing Pb from gasoline combustion in Canada (1.13--1.16). By contrast, very few Canadian waterfowl, loons or eagles that had experienced elevated Pb exposure had 206Pb:207Pb ratios similar to that of Pb originating from Canadian gasoline combustion. Pb in soils, sediments and biota derived from leaded gasoline combustion was not the primary source of elevated Pb exposure and toxicity for most individuals of these species. The range and pattern of the 206Pb:207Pb ratios for Pb-exposed waterfowl and eagles was very similar to that for Pb shot pellets purchased or recovered from lake sediments, consistent with the contention that the ingestion of Pb shot (or Pb sinker in the case of common loons) is the main cause of elevated Pb exposure in these species. In addition, the isotope ratios for all species were higher than that characterizing Pb from Precambrian mining and smelter sources (206Pb:207Pb = 0.93--1.07), indicating that none of the birds examined in the present study had experienced elevated Pb exposure from Precambrian mining or smelting wastes. We conclude that stable Pb isotope analysis is useful for distinguishing between potential sources of Pb exposure in wildlife and that Pb shot ingestion is the cause of most of the elevated Pb exposure in waterfowl and their predators in Canada

Effects of lead shot ingestion on free-ranging mourning doves.

Mourning doves (Zenaida macroura) may develop Pb toxicosis from ingesting spent Pb shot from hunted fields in which they feed. One to 6.5 percent of the dove population may ingest Pb shot based on analysis of gizzard contents. No Pb shot toxicity studies have been conducted on free-ranging mourning doves. Mortality data for Pb-dosed, free-ranging doves would help determine the actual effects of Pb shot ingestion on the mourning dove population. Causes of death of Pb-treated doves also could help to estimate exposure of predators and scavengers to secondary Pb toxicosis. The objectives of this study were to compare mortality and causes of death of free-ranging Pb-treated and untreated mourning doves.