Lead Shot Ingestion Research Articles

Incidence of lead ingestion in managed goose populations and the efficacy of imposed restrictions on the use of lead shot

Lead is a toxic heavy metal that when ingested can cause death or sub‐lethal fitness effects. Despite its toxicity, it is still widely used in recreational and management shooting globally. To reduce the impacts of lead on wildfowl, recent European Union legislation has banned the use of lead shot in and around wetlands from 2023. Understanding the effectiveness of such mitigation is vital to inform future policy. On Islay, Scotland, the licensed shooting of Barnacle Geese Branta leucopsis to reduce agricultural damage has adhered to the ban on use of lead shot over Ramsar‐designated wetlands legislated in Scotland in 2004. On average 2380 lead cartridges were fired annually between 2005 and 2020 outside designated wetlands, where Barnacle Geese and other wildfowl forage. From faecal samples, it is possible to infer whether birds have ingested lead and are therefore potentially suffering from lead poisoning. After sampling faeces from Barnacle Geese (n = 193) and Greenland White‐fronted Geese Anser albifrons flavirostris (n = 150) we found only four (1.2%) faecal samples with elevated lead levels that may be indicative of lead shot ingestion. Further post‐mortem examinations (n = 102 Barnacle Geese only) and X‐ray of live birds (n = 293) revealed similarly low levels of shot ingestion in both species (post‐mortem < 4%, and X‐ray < 2%), corroborating findings from faecal sample analysis. When subsequently accounting for limited shot retention time within individuals, the proportion of each population ingesting a single lead shot over a winter was estimated at a maximum of 9.4% (Barnacle Geese) and 16.8% (White‐fronted Geese). We propose that high compliance with the ban on using lead shot over wetlands because of carefully controlled shooting management on Islay has led to relatively low instantaneous ingestion rates, probably resulting in minimal lead poisoning mortality. However, ingestion was not eliminated and the potential fitness effect of chronic lead poisoning in both goose populations therefore persists, although use of lead shot in organized shooting has subsequently been discontinued. Recent European Union bans on lead shot use over wetlands may reduce lead ingestion in waterfowl if compliance rates are high, but as foraging often occurs outside wetlands (as in this study), further restrictions including use on other key foraging sites may help to further mitigate the risk of lead poisoning in waterfowl.

Method to assess the potential magnitude of terrestrial European avian population reductions from ingestion of lead ammunition.

Current estimates of terrestrial bird losses across Europe from ingestion of lead ammunition are based on uncertain or generic assumptions. A method is needed to develop defensible European-specific estimates compatible with available data that does not require long-term field studies. We propose a 2-step method using carcass data and population models. The method estimates percentage of deaths diagnosed as directly caused by lead poisoning as a lower bound and, as an upper bound, the percentage of possible deaths from sublethal lead poisoning that weakens birds, making them susceptible to death by other causes. We use these estimates to modify known population-level annual mortality. Our method also allows for potential reductions in reproduction from lead shot ingestion because reductions in survival and reproduction are entered into population models of species with life histories representative of the most groups of susceptible species. The models estimate the sustainability and potential population decreases from lead poisoning in Europe. Using the best available data, we demonstrate the method on two taxonomic groups of birds: gallinaceous birds and diurnal raptors. The direction of the population trends affects the estimate, and we incorporated such trends into the method. Our midpoint estimates of the reduction in population size of the European gallinaceous bird (< 2%) group and raptor group (2.9–7.7%) depend on the species life history, maximum growth rate, population trend, and if reproduction is assumed to be reduced. Our estimates can be refined as more information becomes available in countries with data gaps. We advocate use of this method to improve upon or supplement approaches currently being used. As we demonstrate, the method also can be applied to individual species of concern if enough data across countries are available.

Toxic lead gunshot persists accessible to waterbirds after a 33-year ban on their use

Use of lead shot for hunting was banned under legislation on 26 Ramsar sites in Denmark from 1986, based on evidence of poisoning in waterbirds ingesting lead shot and high lead shot pellet densities in Danish wetland sediments caused by intensive hunting. To assess the fate of lead shot from hunting prior to 1986 and the degree to which such shot remains available to waterbirds, this study replicated the survey of shot pellet densities in substrates in Ringkøbing Fjord undertaken in the late 1970s. 287 shotgun pellets (282 lead, five steel) were recovered from 123 sediment samples at four locations, equivalent to a mean of 127 pellets m−2 in the top 20 cm of the sediment at the four locations, in certain hot spots equating to >250 kg lead ha−1, broadly similar to densities found in the 1970s. Possible explanations were given for the persistence of such high lead shot densities despite >30 years of regulation, during which time steel shot has been widely used as the alternative to lead. Field experiments showed that steel shot corroded in the marine environment, which likely contributes to lower steel shot densities found in this study. It is concluded that lead gunshot pellet dispersal and accumulation in natural ecosystems remains as a persistent and irreversible hazard to wildlife and ecosystems. Based on these Danish experiences, it is urgently recommended that international and national bodies in countries where hunting with lead shot continues recognise these results and act to prevent the accumulation of this toxic metal.

Ingested shot in mallards (Anas platyrhynchos) after the regulation of lead shot for hunting in Denmark

Since 1986, lead-based gunshot has been banned inter alia for hunting in ponds with the release of mallards (Anas platyrhynchos) in Denmark. To assess whether ingestion of gunshot by this common waterbird has changed as a result of this regulation, we purchased 690 mallard gizzards from ten Danish hunting districts with a program for the rearing and release of mallards for shooting purposes. After X-ray examination, embedded and ingested shot were removed by dissection and subjected to type classification. Of the 690 gizzards, 66 (9.6%) had ingested shot in different combinations of steel, bismuth and lead. The prevalence and occurrence of shot in general were higher than in previous Danish and other studies. However, prevalence of lead shot was markedly lower, and the ingestion of non-lead shot exceeded the levels of ingested lead shot by a factor 10. The result demonstrated that lead shot has become less available over time, although it is still present despite the ban of lead-based ammunition in habitats of released mallards in 1986. Our study proves the hypothesis that mallards have switched from ingesting lead to steel shot due to the change of shot types for hunting in their habitat and indirectly demonstrates that the Danish phase-out of lead shot for hunting has led to decreased levels of waterbird poisoning. No gizzards were detected with embedded lead shot, which demonstrated a full compliance with the lead shot regulation in this sample.

Economic assessment of wild bird mortality induced by the use of lead gunshot in European wetlands

In European wetlands, at least 40 bird species are exposed to the risk of lead poisoning caused by ingestion of spent lead gunshot. Adopting a methodology developed in North America, we estimated that about 700,000 individuals of 16 waterbird species die annually in the European Union (EU) (6.1% of the wintering population) and one million in whole Europe (7.0%) due to acute effects of lead poisoning. Furthermore, threefold more birds suffer sub-lethal effects. We assessed the economic loss due to this lead-induced mortality of these 16 species by calculating the costs of replacing lethally poisoned wild birds by releasing captive-bred ones. We assessed the cost of buying captive-bred waterbirds for release from market surveys and calculated how many captive-bred birds would have to be released to compensate for the loss, taking into account the high mortality rate of captive birds (72.7%) in the months following release into the wild. Following this approach, the annual cost of waterbird mortality induced by lead shot ingestion is estimated at 105 million euros per year in the EU countries and 142 million euros in the whole of Europe. An alternative method, based upon lost opportunities for hunting caused by deaths due to lead poisoning, gave similar results of 129 million euros per year in the EU countries and 185 million euros per year in the whole of Europe. For several reasons these figures should be regarded as conservative. Inclusion of deaths of species for which there were insufficient data and delayed deaths caused indirectly by lead poisoning and effects on reproduction would probably increase the estimated losses substantially. Nevertheless, our results suggest that the benefits of a restriction on the use of lead gunshot over wetlands could exceed the cost of adapting to non-lead ammunition.

Ultrastructural study of liver and lead tissue concentrations in young mallard ducks (Anas platyrhynchos) after ingestion of single lead shot

ABSTRACTLead (Pb) represents a serious threat to wildlife and ecosystems. The aim of this study was to examine the subcellular effects of dietary Pb pellet ingestion on mallard (Anas platyrhynchos) livers. After ingestion of a single Pb shot (LS4 size class: 0.177 ± 0.03 g) in 41 mallard ducks (22 males and 19 females) versus 10 controls (5 males and 5 females), all 7-week old, a morphologic study was conducted by TEM (transmission electron microscopy) of liver at the subcellular level. The results in treated mallards showed at a magnification of 2500 X that hepatic parenchyma was altered as evidenced by intralysosomal electron-dense deposits, which are compatible with Pb deposits. Further, at a higher magnification (15,000 X) in both genders, deterioration of mitochondria was observed in which the crests and, to a lesser extent, outer membrane were lysed. While the rough endoplasmic reticulum was fragmented, intracytoplasmic electron-dense material compatible with Pb deposits was maximally visible, thereby underscoring the deeply destructive effect of this metal on the subcellular architecture of the liver. In addition, applying an optimized and validated method in a clean room using electrothermal atomic absorption spectrophotometer (ETAAS) with Zeeman background correction, the objective was to improve and refine certain indispensable measurements pertaining to Pb impregnation in tissues other than liver such as kidneys, bones, and feathers of mallards. Data demonstrated show that compared with controls, Pb accumulation increases significantly, not only in the liver (3-fold), but also in the bones and the feathers (14-fold). No significant difference was noted between males and females. Bearing in mind the marked subcellular toxicity attributed to Pb, this study reinforces present-day arguments advocating limitation of game consumption.

Spent lead shot availability and ingestion by ring‐necked pheasants in South Dakota

ABSTRACTLead is toxic to all vertebrate species and ingestion of lead ammunition has been reported in &gt;130 avian species. Research has primarily focused on the effects and exposure of spent lead shot on waterfowl with little information about effects on upland game species, such as ring‐necked pheasant (Phasianus colchicus). We collected 1,450 soil samples to estimate the availability of lead shot on 2 licensed shooting preserves in South Dakota, USA, 2012–2013. We concurrently collected gizzards from 660 hunter‐harvested wild male pheasants from the shooting preserves and compared lead ingestion rates with those of 1,301 gizzards collected from nonpreserve areas. Spatial modeling showed the distribution of spent lead shot was associated with the systematic hunting pattern of each study site and, to a lesser extent, land‐use type. Prevalence of ingested lead shot was 4.9 times greater for birds harvested on shooting preserves (3.9%, 95% CI = 2.7–5.7%) when compared with nonpreserve areas (0.8%, 95% CI = 0.4–1.4%) where lead shot availability was presumed less. Wild pheasants inhabiting areas of artificially high hunting intensity and lead deposition are at elevated risk of lead exposure and poisoning, although the consequences of lead ingestion in wild pheasants are unknown. © 2016 The Wildlife Society.

Can Ingestion of Lead Shot and Poisons Change Population Trends of Three European Birds: Grey Partridge, Common Buzzard, and Red Kite?

Little is known about the magnitude of the effects of lead shot ingestion alone or combined with poisons (e.g., in bait or seeds/granules containing pesticides) on population size, growth, and extinction of non-waterbird avian species that ingest these substances. We used population models to create example scenarios demonstrating how changes in these parameters might affect three susceptible species: grey partridge (Perdix perdix), common buzzard (Buteo buteo), and red kite (Milvus milvus). We added or subtracted estimates of mortality due to lead shot ingestion (4–16% of mortality, depending on species) and poisons (4–46% of mortality) reported in the UK or France to observed mortality of studied populations after models were calibrated to observed population trends. Observed trends were decreasing for partridge (in continental Europe), stable for buzzard (in Germany), and increasing for red kite (in Wales). Although lead shot ingestion and poison at modeled levels did not change the trend direction for the three species, they reduced population size and slowed population growth. Lead shot ingestion at modeled rates reduced population size of partridges by 10%, and when combined with bait and pesticide poisons, by 18%. For buzzards, decrease in mean population size by lead shot and poisons combined was much smaller (≤ 1%). The red kite population has been recovering; however, modeled lead shot ingestion reduced its annual growth rate from 6.5% to 4%, slowing recovery. If mortality from poisoned baits could be removed, the kite population could potentially increase at a rapid annual rate of 12%. The effects are somewhat higher if ingestion of these substances additionally causes sublethal reproductive impairment. These results have uncertainty but suggest that declining or recovering populations are most sensitive to lead shot or poison ingestion, and removal of poisoned baits can have a positive impact on recovering raptor populations that frequently feed on carrion.

Shot Ingestion by Wintering Female Northern Pintails (Anas acuta) in the Texas Coastal Plain, 2012–14

Historically, lead poisoning through lead shot ingestion was one of the largest health issues affecting waterfowl in North America. Lead shot was banned for use in waterfowl hunting in the US in 1991 and was banned in Canada in 1997. However, biologists need to understand how, and if, lead shot remaining in the environment will continue to impact waterfowl. Our goal was to estimate lead and nontoxic shot consumption by female Northern Pintails (Anas acuta) wintering along the Texas coast. We found shot or metal fragments (or both) in the gizzards of 39 (17%) of 227 female Northern Pintails collected along the Texas coast. Of these, lead shot was found in seven gizzards, steel shot was found in 24 gizzards, and other metal and fragments were found in 20 gizzards. Some females consumed multiple shot types. Overall, shot (lead and nontoxic combined) ingestion rates were similar to those found prior to the lead shot ban in Texas (14%) and Louisiana (17%); however, lead shot ingestion rates were considerably lower, suggesting that it is becoming less available over time. All Northern Pintails that had lead shot in their gizzards were collected from coastal habitats. While it seems that lead shot ingestion by Northern Pintails has decreased since the ban was put in place, monitoring lead shot ingestion rates from different regions will provide insight into its availability in different habitats and under various environmental conditions.

Assessment of lead exposure in waterfowl species, Korea.

Lead concentrations were analyzed in white-fronted geese (Anser albifrons, n = 15), mallards (Anas platyrhynchos, n = 4), and spot-billed ducks (A. poecilorhyncha, n = 13) found dead near Gimpo, Korea, to determine tissue- and species-specific lead concentration differences and to assess the effect of embedded lead shot. In livers, kidneys, and bones (tarsus), mallards and spot-billed ducks with embedded shot had greater lead concentrations than white-fronted geese and spot-billed ducks without lead shot. Lead concentrations in spot-billed ducks were greater in bones than in livers and kidneys suggesting chronic exposure to lead. Lead concentrations in 8 of 32 livers, 5 of 32 kidneys, and 9 of 32 bones exceeded the threshold level of abnormal exposure for wild birds (>5 µg/g dw in lives, >6 µg/g dw in kidney, and >6.75 µg/g dw in bone). Increased lead concentrations in soft tissues and bones might be attributed to increased lead shot ingestion and embedded shot. Lead concentrations were correlated between livers and kidneys, between livers and bones, and between kidneys and bones. These results suggest that a relationship between acute exposure in livers and kidneys and chronic exposure in bones.

Lead from hunting activities and its potential environmental threat to wildlife in a protected wetland in Yucatan, Mexico

This study provides insights into the status of lead in the protected wetland of El Palmar, located on the northwestern littoral of the Yucatan Peninsula. This reserve is ecologically and economically important because it provides feeding and breeding habitats for many species, as well as being an ecotourism destination (especially for bird watching). Although it is a protected area, duck species are heavily hunted within the reserve during the winter. As a result, animals feeding or living in sediments could be exposed to anthropogenic lead. Total lead and its geochemical fractionated forms were measured in sediment cores from six selected sites in “El Palmar” wetland, during pre- and post-hunting seasons, to approximate the potential environmental threat (especially for benthonic living/feeding organisms). Anthropogenic lead concentrations detected in soil cores ranged from below the minimum infaunal community effect level (30.24μgg−1) during the pre-hunting season, to bordering the probable infaunal community effect level (112.18μgg−1) during the post-hunting season, according to SquiiRTs NOAA guidelines. Yet, these results were lower than expected based on the intensity of hunting. Consequently, this article explores the possibility that the lower than expected lead concentration in sediments results from (1) degradation of shot and transformation to soluble or particulate forms; or (2) ingestion of lead shot by benthic and other lacustrine species living in the protected area. Geochemical fractionation of lead demonstrated that in the top 6cm of the soil column at heavily active hunting sites (EP5 and EP6), lead was associated with the lithogenic fraction (average 45 percent) and with the organic fraction (average 20 percent). Bioavailable lead (sum of lead adsorbed to the carbonates, Fe/Mn oxyhydroxides and organic fractions) in sediments was lower than 50 percent for the heavily active hunting areas and higher for the rest of the sites. Multivariate analysis showed that the environmental chemistry, the physicochemical characteristics of the water, and the geochemical qualities of the sediments do not favor the release of lead into the water column. Thus, the direct consumption of lead shot by organisms feeding in sea grass or in the top 10cm of sediment is perhaps the major process preventing lead from being deposited in sediments, and, as such, these species (e.g., flamingos and/or ducks) could be threatened by anthropogenic lead pollution.

Effects of lead shot ingestion on bone mineralization in a population of red-legged partridge (Alectoris rufa)

The effect of lead (Pb) toxicity on bone mineralization was investigated in a wild population of red-legged partridge (Alectoris rufa) inhabiting a farmland area contaminated with Pb-shot from recreational hunting activities in Albacete, a southeastern province of Spain. Femora from 40 specimens of red-legged partridge were analyzed for Pb by graphite furnace atomic absorption spectroscopy (GF-AAS), and for bone composition by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The FTIR and DRX data of bone were analyzed in detail to determine possible alterations in bone mineral chemistry and crystallinity due to Pb toxicity. Results showed a marked decrease in the degree of mineralization as Pb concentrations in bone tissue increased while XRD analyses showed that the crystallinity of apatite crystals increased with the Pb load in bone. These load-dependent effects are indicative that Pb contamination altered bone remodeling by reducing new bone mineral formation and demonstrate that bone quality is a sensitive indicator of adverse effects on wild bird populations exposed to Pb pollution.

Pleuropulmonary complications related to pulmonary instillation of activated charcoal

described the interesting case of a 20-year-old female patient who attempted suicide by ingesting lead shot. She was treated with atropine and received 50 g of activated charcoal (AC) diluted in 400 mL of mannitol administered through a gastric tube. A few hours later, the patient vomited, as well as experiencing a decreased level of consciousness and agonal respiration. At bronchoscopy, blackish material mixed with food debris was obtained, characterizing the occurrence of aspiration of the material. Imaging studies revealed bilateral alveolar opacities.We would like to report our experience of a case of attempted suicide in which the pulmonary and pleural complications were due not to aspiration, but to direct instillation of AC into the airways. The patient was a 23-year-old female who was admitted to the hospital approximately one hour and a half after the ingestion of 200 mg of paroxetine. Upon her arrival, she was in a coma and underwent gastric lavage with a solution of 1.5 L of AC. The patient immediately developed dry cough and dyspnea. A chest X-ray showed right pleural effusion, and, during thoracentesis, there was discharge of black fluid, identified as AC (Figure 1). A CT scan showed pleural effusion and consolidation in the right lower lobe, both of which exhibited high density (attenuation values of approximately 130 HU), as well as pneumothorax (Figure 2). These findings raised the suspicion of direct instillation of AC into the lungs due to placement of the nasogastric tube within the patient’s airway. At bronchoscopy, there was discharge of black material from the right lower lobe. An air leak was noted from the chest tube, suggesting bronchopleural fistula. The patient underwent thoracoscopy and pleural lavage. Fifteen days later, the fistula closed, and the patient was discharged from the hospital. Some of the data on this case have been reported in a previous publication.

Multiple lead appendoliths following ingestion of lead shot: Time course and removal by laporoscopic appendectomy

Systemic lead poisoning may occur from ingested lead foreign bodies. Rarely, these may cause a retained appendolith. The risks of lead toxicity from these appendoliths, the time course of retention in the appendix, the rapidity of inhibition of heme synthesis, and the best approach to removal remain controversial. Fourteen days post-ingestion of a “handful” of lead shot, a 15-year-old male was admitted for elevated lead level; an x-ray showed aggregation of many pellets in the teen's appendix. A laparoscopic appendectomy was performed; examination of the removed appendix revealed greater than 50 retained pellets. An abdominal film obtained post-procedure showed removal of all but three of the pellets. Results from admission blood work found a blood lead level of 41 mcg/dL and free erythrocyte porphyrin (FEP) level of 114 μmol/mol heme (reference normal <70). After a short recovery the patient was discharged on succimer chelation therapy and on follow up, his lead level was <5 mcg/dL.

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 (5μg/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.

Ecotoxicological study on lead shot from hunting in the Padule di Fucecchio marsh (Tuscany, Italy)

Ingestion of lead shot has been recognised as an important cause of death in waterbirds for over a century. Chemical dissolution (oxidation) of lead shot in aquatic environments can make lead more available, distributing it throughout the aquatic ecosystem. The extent of the phenomenon has rarely been investigated in Italy and no systematic information is available for Italian wetlands. We investigated lead shot density and lead concentrations in sediment of the Padule di Fucecchio (Tuscany), one of the largest inland marshes in Italy (2000 ha), in order to evaluate the impact of lead shot from hunting. Moreover, to assess lead accumulation in organisms, red swamp crayfish, Procambarus clarkii (Girard 1852), was chosen as a bioindicator. The results showed a high lead shot density (0–311 shot · m−2). Although lead concentrations and lead shot density were slightly less in protected areas than in hunting areas, contamination was widespread throughout the marsh, with a mean lead concentration of 115.6 mg · kg−1 d.w.. Crayfish were subject to heavy uptake of lead, with high concentrations in gut contents (43.84±47.48 mg · kg−1 d.w.) and hepatopancreas (3.217±4.850 mg · kg−1 d.w.). A detailed map of lead contamination was plotted using sediment data. Thematic mapping is a valuable support for environmental remediation and reserve management and assessment of lead contamination concomitant with the banning of lead shot in the area provides a useful database for long-term monitoring of the effectiveness of the ban.

Ingestion of Lead and Nontoxic Shot by Green-winged Teal (Anas crecca) and Northern Shovelers (Anas clypeata) from the Mid-Gulf Coast of Texas, USA

Ninety-eight Green-winged Teal (Anas crecca) and 84 Northern Shoveler (Anas clypeata) gizzards were examined for ingested shot. One Northern Shoveler had lead and three had steel shot; 24 teal and 17 shovelers had composite nontoxic shot or nonlead metal fragments. Prevalence of ingested lead appears minimal and consistent with other studies conducted after lead-shot bans.

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.

Lead, mercury, cadmium, chromium, and arsenic levels in eggs, feathers, and tissues of Canada geese of the New Jersey Meadowlands

The New Jersey Meadowlands are located within the heavily urbanized New York/New Jersey Harbor Estuary and have been subject to contamination due to effluent and runoff from industry, traffic, and homes along the Hackensack River and nearby waterways. These extensive wetlands, though heavily impacted by development and pollution, support a wide array of bird and other wildlife species. Persistent contaminants may pose threats to birds in these habitats, affecting reproduction, egg hatchability, nestling survival, and neurobehavioral development. Metals of concern in the Meadowlands include arsenic, cadmium, chromium, lead, and mercury. These metals were analyzed in eggs, feathers, muscle, and liver of Canada geese ( Branta canadensis) breeding in four wetland sites. We sampled geese collected during control culling ( n=26) and collected eggs from goose nests ( n=34). Levels of arsenic were below the minimum quantification level (MQL) in most samples, and cadmium and mercury were low in all tissues sampled. Chromium levels were high in feather samples. Mercury levels in eggs of Canada geese, an almost exclusively herbivorous species, were lower (mean ±SE 4.29±0.30 μg/g wet weight) than in eggs of omnivorous mallards ( Anas platyrhynchos), and insectivorous red-winged blackbirds ( Agelaius phoeniceus) and marsh wrens ( Cistothorus palustris) from the Meadowlands, consistent with trophic level differences. However, lead levels were higher in the goose eggs (161±36.7 ng/g) than in the other species. Geese also had higher levels of lead in feathers (1910±386 ng/g) than those seen in Meadowlands passerines. By contrast, muscle and liver lead levels were within the range reported in waterfowl elsewhere, possibly a reflection of metal sequestration in eggs and feathers. Elevated lead levels may be the result of sediment ingestion or ingestion of lead shot and sinkers. Finally, lead levels in goose liver (249±44.7 ng/g) and eggs (161±36.7 ng/g) may pose a risk if consumed frequently by humans. Mill Creek, the site with the most documented prior contamination, had significantly elevated cadmium, chromium, mercury, and lead in goose tissues.

Lead shot ingestion by mourning doves on a disked field

AbstractPrevious field studies of hunter‐harvested mourning doves (Zenaida macroura) have reported the percentage of birds with ingested lead shot as 0.2–6.5%. To reduce the uncertainty concerning the number of doves that ingest shot, we conducted an experiment to test the proportion of mourning doves that ingested lead shot on the bare soil of a disked field (typical of a managed dove field) to simulate more natural feeding conditions. In each of 3 treatment groups of 80 birds, we exposed 35 birds to low‐density lead shot (1.5 million shot/ha), and35 birds to high‐density lead shot (29.5 million shot/ha), and 10 birds served as controls (no shot). We dosed 5 positive control birds with 2 lead shot each in trials 2 and 3. We scattered lead shot and mixed seed on the loosely packed soil of treatment cages and after 4 days of exposure, 2.9% of doves voluntarily ingested ≥1 lead shot. The proportion of birds that ingested shot when exposed to the high‐density shot treatment (4.9%) was not different (P = 0.098) from that of the low‐density shot treatment (1.0%). Lead concentrations in liver, kidneys, and blood reached maxima of 94.402 ppm, 346.033 ppm, and 13.883 ppm wet mass, respectively. Differences in delta‐aminolevulinic acid dehydratase (ALAD) activity, packed cell volume, and heterophil:lymphocyte ratio (H:L) were greater posttreatment in doves that had ingested shot than in those that did not. The risk posed to mourning doves from lead shot ingestion can be reduced by banning lead shot on management areas or dove fields or disking fields after hunting season to reduce shot availability. © 2011 The Wildlife Society.