Lead Gunshot Research Articles

Effectiveness of regulations intended to reduce the use of lead shotgun ammunition in and over coastal intertidal and riparian habitats in Scotland

The use of lead shot for hunting in wetlands is banned in many countries because ingestion of spent shot causes lead poisoning of wildfowl. In Scotland (UK), the Environmental Protection (Restriction on Use of Lead Shot) (Scotland) (No. 2) Regulations 2004 were introduced to reduce the exposure of wildfowl to lead shot by making its use in wetlands unlawful. We assessed the degree to which the regulations are being complied with by wildfowlers by conducting analyses of the shot metal type contained within shotgun cartridges discarded in coastal intertidal and riparian habitats across Scotland. Despite efforts to encourage compliance with the regulations, which had been in force for 17-18 years at the time of the surveys, about half of the cartridges used appeared to have contained lead gunshot, indicating unlawful use. Hence, efforts to restrict the use of lead ammunition in coastal and riparian wetlands by regulation, with the intention of reducing the risk of lead poisoning of waterfowl, have had limited effectiveness so far.

Promoting the Transition to Non-Lead Hunting Ammunition in the European Union Through Regulation and Policy Options

Regulation (EU) 2021/57, banning the use of lead gunshot in wetland hunting, and adoption of the proposed European Union (EU) restriction on lead ammunition use by civilians in other types of hunting and target shooting, would complete the transition to non-lead ammunition use in the EU and ensure major compliance among hunters and shooters. The transition is possible since non-lead substitutes for all types of shotgun and rifle ammunition are produced already by leading European manufacturers. To ensure ammunition non-toxicity, EU standards are needed for lead substitutes to accompany both existing and potential future lead ammunition restrictions. Meat from wild game birds and mammals is a large and important commodity in the EU. Setting a maximum lead level in all marketed game meats under Regulation (EC) 1881/2006, aided by mandatory food labelling, would add extra health protection to human consumers. This regulatory step would help ensure that all wild game destined for retail markets were taken with non-lead ammunition, would complement existing and proposed European Commission restrictions on lead hunting ammunition and aid monitoring and enforcement. Increased public awareness of the risks posed by lead from ammunition to the health of humans, wildlife, and the environment, and especially their associated externalized costs to society, would promote and facilitate the passage of regulation to protect human and environmental health from toxic lead ammunition.

Lead contamination in tissues of large avian scavengers in south-central Europe.

Lead poisoning from spent ammunition is known to affect many avian species. Birds of prey ingest lead when feeding on game shot with lead gunshot or bullets. Raptors with scavenging habits are particularly vulnerable to ingesting lead in areas with intensive hunting and are good indicators of the risk of poisoning from lead ammunition. To assess how much facultative and obligate avian scavengers suffer lead contamination in south-central Europe, between 2005 and 2019 we collected and analysed 595 tissue samples from 252 carcasses of 4 species (golden eagle, bearded vulture, griffon vulture, cinereous vulture). Lead concentrations in organs showed a similar pattern across species with long and small bones revealing the highest median values (5.56 and 6.8mg/kg w.w., respectively), the brain the lowest (0.12), and the liver and kidney the intermediate (0.47 and 0.284). Overall, 111 individuals (44.0%) had lead concentrations above background thresholds in at least one tissue (i.e. >2mg/kg w.w. in soft tissues, >8.33 in bone) and 66 (26.2%) had values indicating clinical poisoning (>6mg/kg w.w. in liver, >4 in kidney, >16.6 in bone). Tissue lead concentrations and incidence of clinical and sub-clinical poisoning were higher in golden eagles and griffon vultures than in bearded and cinereous vultures, likely due to different feeding habits. In all species we found a rapid increase in lead values with age, but differences between age classes were significant only in the golden eagle. Birds with lead fragments in their digestive tract, as detected by X-rays, had higher median lead concentrations, suggesting that hunting ammunition is the main source of lead poisoning. Our results imply that lead impacts the demography of these long-lived species with delayed sexual maturity and low reproduction rate. A rapid transition towards lead-free bullets and gunshot is therefore required across Europe.

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.

Regulations on lead ammunition adopted in Europe and evidence of compliance.

The transition to non-lead ammunition has been enforced by regulations on use and possession of lead shot and rifle bullets. Here we review the scientific and technical literature about this regulatory process in Europe and give some notes of its effectiveness to reduce this source of lead contamination in aquatic and terrestrial environments. Presently, lead shot use has been legally restricted in 23 European countries. Two, Denmark and The Netherlands, have a total ban of lead gunshot use in all types of habitats, 16 countries have a total ban in wetlands and/or for waterbird hunting, and 5 have a partial ban implemented only in some wetlands. The legal regulation of lead bullets is limited to some German regions. This review also highlights the need to know the level of compliance with the ban on lead ammunition and the subsequent benefits for the susceptible species and for game meat safety.

Wildlife, human and environmental costs of using lead ammunition: An economic review and analysis

A proposed European Union (EU)-wide restriction on the use of lead gunshot for shooting in and over wetlands estimated that the societal benefits of a restriction outweighed costs, despite few identified benefits being quantified economically. A subsequent Annex XV Investigation Report on the evidence of impacts of lead ammunition in terrestrial environments concluded that additional measures to control its use are warranted, although to date this has not been further evaluated. To help inform this process, we review the literature and undertake new analyses to estimate the costs of continued use of lead ammunition associated with impacts on wildlife, people and the environment. We estimate minimum annual direct costs across the EU and Europe of c. €383 million–€960 million and €444 million–€1.3 thousand million respectively. The value that society places on being able to avoid these losses, estimated using a ‘willingness to pay’ approach, was c. €2.2 thousand million for wildfowl alone. Our estimated costs of the continued use of lead ammunition across the EU appear to be considerably greater than the likely costs of switching to non‐toxic alternative ammunition types, although these have not been formally estimated in full.

Rationale for the regulated transition to non-lead products in Canada: A policy discussion paper

Lead gunshot, rifle bullets, and fishing weights are still allowed in Canadian provincially-regulated hunting and fishing, despite the contribution to lead exposure in humans, wildlife, and the environment. Non-lead gunshot and fishing weights are required in Canada only for waterfowl hunting, and angling in national parks and national wildlife areas. Lead wheel weights are also allowed and comprise a majority of the Canadian market. Effective non-lead substitutes for these products exist, and are already required in various American and European jurisdictions. Several analyses commissioned by the Canadian government in 2018 identified the problems of lead exposure attributable to these four lead products. Lead is already listed under Schedule 1 of the Canadian Environmental Protection Act (CEPA) that authorizes the government to undertake measures to reduce exposure. CEPA could require, simultaneously, use of non-lead ammunition, fishing weights and wheel weights at the national level, following an appropriate phase-in period. The low provincial and territorial licence fees for hunting and fishing in Canada would offset any costs associated with use of lead substitutes. Costs for non-lead wheel weights would comprise a small percentage of the costs of new vehicles and new tire purchases. This regulatory initiative would complement other Canadian national bans on lead products. Because there is no safe threshold level for blood lead, use of non-lead products would benefit the health of humans, scavengers, upland game species, and fish-eating birds.

Lead Gunshot Ingestion By A Peregrine Falcon

Summary. Lead ammunition represents a source of poisoning for raptors eating game. Although the Peregrine Falcon Falco peregrinus commonly preys on gamebirds, only a few cases of lead poisoning have been recorded, probably owing to the lack of specific investigations. We document an adult female found dead with many lead shot in the digestive tract, mixed with the remains of a feral Pigeon Columba livia domestica and a European Starling Sturnus vulgaris. Concentrations in heart blood clot, liver, kidney and bone suggest that lead poisoning was not the ultimate cause of death. However, lead levels in the blood clot suggest that a small amount of lead may have been absorbed from the shot. The two prey species involved cannot be hunted in Italy but they are intensively shot all year round to prevent damage to crops. —Andreotti, A., Fabbri, I., Menotta, S. & Borghesi, F. (2018). Lead gunshot ingestion by a Peregrine Falcon. Ardeola, 65: 53–58.

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.

Heavy metals in the mallard Anas platyrhynchos from eastern Austria.

A total of 77 specimens of the mallard Anas platyrhynchos were sampled from the eastern part of Austria before the ban on lead gun shot for hunting water fowl. Samples of muscle and liver were analyzed for their content of Cr, Cu, Zn, Ag, Cd, Hg and Pb using atomic absorption spectrometry. In addition the Hg content of feather samples from this aquatic bird species was evaluated. Results generally show higher concentrations of the metals in the liver compared to muscle; for mercury the concentrations were feathers>liver>muscle. Elevated, in some cases critical concentrations of Cr, Cu, Cd, Hg and Pb were measured. Levels of Ag were recorded for the first time for this species from Europe, providing basic information for future evaluation of this upcoming pollutant in aquatic environments.

Possible effects of ingested lead gunshot on populations of ducks wintering in the UK

Although the use of lead ammunition for shooting wildfowl and/or over listed wetlands in the UK has been banned, c. 70% of ducks shot in England (the only UK country with compliance monitoring) are still shot with lead and the proportion of ducks found dead with signs of lead poisoning from ingested gunshot has not declined significantly since the ban. However, there is little quantitative evidence of the impacts of additional mortality from lead poisoning on duck populations. For the eight duck species that winter in freshwater habitats in the UK, we found that inter‐specific variation in mean population growth rate during the period 1990/1991 to 2013/2014 was significantly negatively correlated with two independent measures of the prevalence of ingested lead gunshot in the UK and Europe. This relationship was found for a wide range of different periods over which population growth was estimated, and also for annual growth rates in the period 1966/1967 to 2013/2014, derived from smoothed population trajectories. These findings support the hypothesis that ingested lead gunshot might affect population trend. An alternative hypothesis, that migratory short‐stopping driven by climate change affected trends in numbers of ducks wintering in the UK, was not supported by simple or partial correlation results. The possible impact of ingested lead gunshot on the Common Pochard Aythya ferina, a species listed as globally threatened, is of special concern.

Widespread exposure to lead affects the body condition of free-living whooper swans Cygnus cygnus wintering in Britain

Lead poisoning, through the ingestion of spent lead gunshot, is an established cause of morbidity and mortality in waterbirds globally, but the thresholds at which blood levels begin to affect the physiology of birds in the wild are less well known. Here we determine the prevalence of lead exposure in whooper swans and, for the first time, identify the level of blood lead associated with initial reductions in body condition. Blood lead elevated above background levels (i.e. >20 μg dL−1) was found in 41.7% (125/300) of swans tested. Blood lead was significantly negatively associated with winter body condition when levels were ≥44 μg dL−1 (27/260 = 10%). Our findings indicating that sub-lethal impacts of lead on body condition occur at the lower end of previously established clinical thresholds and that a relatively high proportion of individuals in this population may be affected, reaffirm the importance of reducing contamination of the environment with lead shot.

Poisoning from lead gunshot: still a threat to wild waterbirds in Britain

Lead is a highly toxic metal known to be an important cause of morbidity and mortality in waterbirds and terrestrial birds worldwide. The risk to birds of poisoning from lead has resulted in the introduction of legislation in many countries, such as UK restrictions on the use of lead in angling weights and lead gunshot. In this study, we examined data on current and historical trends in lead poisoning in British waterbirds and related these to the introduction of legislation restricting the use of lead. Our results indicate that lead poisoning has continued to affect a wide range of British waterbirds long after legal restrictions were introduced. Elevated levels of lead (i.e. >20.0 μg/dL) were found in the blood of 34 % (n = 285) of waterbirds tested at four sites in Britain during the 2010/2011 winter and accounted for the deaths of at least 10.6 % (n = 2,365) of waterbirds recovered across Britain between 1971 and 2010 and 8.1 % (n = 1,051) between 2000 and 2010, with lead gunshot being the most likely source of poisoning. The proportion of birds dying from lead poisoning in England did not vary significantly after the introduction of legislation, accounting for 13.7 % of non-infectious causes of death between 1971 and 1987 (n = 204), 20.8 % (n = 360) between 1988 and 1999 and 11.8 % (n = 423) between 2000 and 2010, despite a significant change in lead-related mortality in mute swans found during the same time period, 25 % (n = 12) between 1971 and 1987, 4.6 % (n = 65) between 1988 and 1999 and 2 % (n = 100) between 2000 and 2010. Existing legislation needs review and extension to ensure the delivery of international commitments and a broad-scale transition to the use of non-toxic shot and angling materials in all environments.

Penetrating ocular gunshot injury in a Labrador Retriever

A 3½-year-old, female (spayed) working black Labrador Retriever was referred to the Unit of Comparative Ophthalmology at the Animal Health Trust after a penetrating lead gunshot injury to the right eye. Clinical examination revealed penetrating injuries to the right cornea, left lateral canthus, and left forelimb. Radiography revealed the presence of multiple metallic foreign bodies in the head and one in the left forelimb. B-mode ocular ultrasonography confirmed the presence of an intraocular metallic foreign body within the posterior tunics of the right eye. Medical treatment of the right eye over a period of 1 month resulted in a comfortable, visual eye. Long-term follow-up over 4½ years revealed a slow deterioration in vision because of progressive lens opacification and the presence of a localized area of chorioretinopathy.

Potential Hazard to Human Health from Exposure to Fragments of Lead Bullets and Shot in the Tissues of Game Animals

BackgroundLead is highly toxic to animals. Humans eating game killed using lead ammunition generally avoid swallowing shot or bullets and dietary lead exposure from this source has been considered low. Recent evidence illustrates that lead bullets fragment on impact, leaving small lead particles widely distributed in game tissues. Our paper asks whether lead gunshot pellets also fragment upon impact, and whether lead derived from spent gunshot and bullets in the tissues of game animals could pose a threat to human health.Methodology/Principal FindingsWild-shot gamebirds (6 species) obtained in the UK were X-rayed to determine the number of shot and shot fragments present, and cooked using typical methods. Shot were then removed to simulate realistic practice before consumption, and lead concentrations determined. Data from the Veterinary Medicines Directorate Statutory Surveillance Programme documenting lead levels in raw tissues of wild gamebirds and deer, without shot being removed, are also presented. Gamebirds containing ≥5 shot had high tissue lead concentrations, but some with fewer or no shot also had high lead concentrations, confirming X-ray results indicating that small lead fragments remain in the flesh of birds even when the shot exits the body. A high proportion of samples from both surveys had lead concentrations exceeding the European Union Maximum Level of 100 ppb w.w. (0.1 mg kg−1 w.w.) for meat from bovine animals, sheep, pigs and poultry (no level is set for game meat), some by several orders of magnitude. High, but feasible, levels of consumption of some species could result in the current FAO/WHO Provisional Weekly Tolerable Intake of lead being exceeded.Conclusions/SignificanceThe potential health hazard from lead ingested in the meat of game animals may be larger than previous risk assessments indicated, especially for vulnerable groups, such as children, and those consuming large amounts of game.

Bone lead levels and lead isotope ratios in red grouse from Scottish and Yorkshire moors

Leg and foot bones of adult and juvenile red grouse ( Lagopus lagopus scoticus) were collected from hunter-shot birds on two Scottish estates (Glendye and Invermark) and one Yorkshire estate in September, 2003. The lead content of bones was measured by atomic absorption spectrophotometry, and corresponding stable lead isotopes (Pb 204, 206, 207, 208) by inductively coupled plasma mass spectrometry. At the Glendye ( N = 111) and Invermark ( N = 85) estates, relatively few birds (5.4% and 3.5%, respectively) had highly elevated bone lead concentrations (> 20 µg/g dry weight). In bones of these highly exposed birds, a combination of Pb 206:Pb 207 and Pb 208:Pb 207ratios was consistent with ingestion of lead gunshot available in Europe. By contrast, Yorkshire grouse experienced a high incidence (65.8%) of bone lead > 20 µg/g. The Pb 206:Pb 207 and Pb 208:Pb 207ratios in bones of these highly exposed birds were consistent with a combined exposure to ingested lead gunshot and lead from galena mining in the region. Lead isotope ratios also indicated that lead from UK gasoline combustion and fallout from atmospheric particles was not a likely source of elevated lead in bones of either Scottish or Yorkshire grouse. Suggested management options for the three moors include adopting nontoxic shot for all game shooting on the estates, allowing heather ( Calluna vulgaris) vegetation to grow tall in lead shot fall-out zones to reduce physical access to high densities of lead shot already present, and provision of calcareous grit across moors to reduce lead assimilation from all ingested sources of lead.

Incidence of ingested lead gunshot in wild grey partridges (Perdix perdix) from the UK

From 1947 to 1992, successive pathologists at The Game Conservancy Trust carried out 1,318 post-mortems on adult wild grey partridges found dead in the UK. During a study of chick food from 1968 to 1978 on the Sussex Downs, the gizzards of 29 wild chicks aged up to 6 weeks were also examined. This paper reports the incidence of lead gunshot ingestion in these two groups of birds. On the assumption that there is no temporal bias, the incidence of lead poisoning increased from 1947–1958 to 1963–1992. During 1963–1992, the incidence of lead gunshot ingestion was 4.5±1.0% in adults and 6.9±4.7% in chicks. The weights of individual lead shot in the chick gizzards showed a rapid rate of erosion, indicating a short retention time in the gizzard, as also reported for adult waterfowl and game birds. The incidence rates in grey partridge and waterfowl found dead can therefore be compared. From 1963 to 1992, the overall incidence of ingested lead gunshot in the grey partridge in the UK was 52% of that of waterfowl (Anatidae excluding mute swan), significantly lower.

Lead concentrations in birds of prey in Britain

This paper reports on lead (Pb) concentrations in the livers of 424 individuals of 16 raptor species found dead and sent for analysis to the Institute of Terrestrial Ecology, Monkswood, from the early 1980s to the early 1990s. Elevated Pb concentrations in liver (>20 ppm dry wt), within the range associated with Pb poisoning mortality in raptors, were recorded in one peregrine (4% of species sample) and one buzzard (2% of species sample). These birds are likely to have ingested lead gunshot in the flesh of their prey. Another one each of these species had liver Pb concentrations of 15–20 ppm dry wt, reflecting unusually high absorption of Pb. No individuals of any other species had >15 ppm dry wt liver Pb, although some had 6–15 ppm. The source of Pb in these birds was unknown, but it could have resulted from high Pb concentrations in prey items, including some containing lead shot. Median liver Pb concentrations were generally very low (ranging from <0·07 to 1·61 ppm dry wt for species with sample sizes exceeding 10). In sparrowhawks, for which a large sample was available, liver Pb concentrations in all but one individual were low (<2·6 ppm dry wt). Pb concentrations in juveniles were significantly lower than in adults, and were lowest in recently fledged birds.

Lead Determination in Avian Blood: Application to a Study of Lead Contamination in Raptors from France

Abstract Marsh harriers and other raptors may become poisoned by ingesting lead gunshot in the flesh of their prey. Blood lead is a suitable indicator of exposure to lead. The method usually used in our laboratory for the analysis of human blood induced coagulation of avian blood. In this paper we report upon the optimization and quality control of a method to determine lead in avian blood samples. Samples were prepared using a diluent and matrix modifier. Analysis was carried out using graphite furnace AAS with a L'vov platform and Zeeman-effect background correction. The method was validated using international intercalibration comparisons of lead in human blood. The method proved to have a high degree of sensitivity, reproducibility and accuracy. The detection limit was low (0.004 ppm). The method used is discussed in relation to those previously used for lead analysis in avian blood.

Mortality and hematology associated with the ingestion of one number four lead shot in black ducks, Anas rubripes.

The black duck (anas rubripes) is a dabbling duck endemic to North America. Since population surveys of this species began in the early 1950's, numbers have declined steadily at the rate of approximately 1.5% a year. In 1980 the North American population was estimated to be only 42% of that recorded in 1952. Several reasons have been suggested for this decline. One environmental contaminant that may be contributing to the decline is spent lead gunshot. The ingestion of gunshot by waterfowl is well documented and is thought to kill an estimated 1.6-3.8 million waterfowl each year in North America. There has been little research concerning the toxicity of lead gunshot to the black duck and the present significance of lead poisoning as a mortality factor in this species. This study reports the results of an experiment in which captive black ducks were dosed with one number four lead shot. Mortality rates and hematological effects are discussed in relation to lead toxicity.