Use Of Lead Shot Research Articles

Heavy metals in flamingos ( Phoenicopterus ruber) from Italian wetlands: The problem of ingestion of lead shot

Waterbirds are exposed to many contaminants, including lead from ingestion of shot and fishing sinkers. Lead poisoning had never been reported in flamingos wintering in Italian wetlands. Our investigation stems from a case of four flamingos found dead in Tuscany in 2002 with numerous lead shot in their gizzards. We therefore considered other specimens found dead in different Italian wetlands. Many lead shot found in gizzards and lead tissue concentrations confirmed the hypothesis of lead poisoning in two of the seven specimens analysed: concentrations in liver, kidney, and bone were 361.3, 265.09, and 43.31 μg/g d.w., respectively. Lead organotropism was typical of acute poisoning. Cadmium and mercury were also determined, and found to be in line with what little data are available on this species in the literature. Although Italy recently endorsed the African–Eurasian Waterbird Agreement (AEWA) prohibiting use of lead shot for hunting in wetlands, our results reveal a first case of lead shot poisoning in flamingos wintering in Italian wetlands. This evidence sounds a further warning of the problem of spent lead shot in countries where hunting in wetlands is not strictly regulated.

Lead in the tissues of terrestrial raptors in southern Ontario, Canada, 1995–2001

Terrestrial raptors which feed on upland hunted game species may increase their risk to lead exposure and lead poisoning by ingesting lead shot found in the tissues of prey. Lead exposure in 225 individuals of nineteen species of terrestrial raptors, collected as carcasses in southern Ontario from 1995–2001, was examined through the analysis of bone, liver and kidney tissues. In this study, one red-tailed hawk contained liver lead concentrations and exhibited signs consistent with lead poisoning. Liver and kidney concentrations of one turkey vulture were also significantly higher than that associated with subclinical effects. This same bird, plus another turkey vulture and a northern harrier, had elevated bone lead concentrations (> 10 μg/g dw) associated with possible toxicity. Turkey vultures had the highest mean concentrations of lead in bone and kidney compared to other raptor species. While it appeared only a single bird suffered acute lead poisoning, lead levels exceeded threshold concentrations associated with subclinical or acute toxicity in 4 of 225, almost 2%, of terrestrial raptors assessed. Given the association between lead exposure in raptors and hunting of game species reported in other studies, the continued use of lead shot for upland hunting in Ontario likely remains as one of the primary sources of lead and a continued risk to these birds of prey.

Incidence of Artifact Ingestion in Mute Swans and Tundra Swans on the Lower Great Lakes, Canada

Although lead poisoning is common in swans, no information exists on the prevalence of lead artifact ingestion in swans using the lower Great lakes (LGL). We examined artifact ingestion (lead and non-toxic) in Mute Swans Cygnus olor and Tundra Swans Cygnus columbianus collected on the LGL in Ontario (1999–2003) following the 1999 ban on use of lead shot for waterfowl hunting in Canada. A larger proportion of Mute Swans (19.8% of 243 birds) contained artifacts than did Tundra Swans (6.5% of 77 birds), possibly due to the fact that Mute Swans feed exclusively in aquatic habitats. Overall, 14% of Mute Swans contained nontoxic shot, 6% contained lead shot and 1.6% contained fishing tackle; 4% of Tundra Swans contained non-toxic shot and 2.6% contained lead shot. Adult Mute Swans (22.7%) had a higher incidence of artifact ingestion than did cygnets (8.9%), but there were no age-related differences in Tundra Swans. No sex-related differences in artifact ingestion were detected in either species. Given the overall frequency of shot ingestion in Mute Swans (20% of birds), lead toxicosis probably was a significant mortality factor for this species on the LGL before the lead shot ban. As only 1.6% of Mute Swans and no Tundra Swans contained any form of fishing tackle, angling related injuries and mortalities are likely lower in the LGL than has been reported for swans in Europe. Presently, lead toxicosis is likely having a low to moderate effect on Mute Swans and a minimal effect on Tundra Swans on the LGL.

Shot Ingestion in Scaup on the Lower Great Lakes After Nontoxic Shot Regulations in Canada

Use of lead shot for waterfowl hunting was banned in the United States in 1991 to reduce the incidence of lead toxicosis in waterfowl. In 1999 Canada implemented a similar ban. The lower Great Lakes (LGL) are important migratory areas for greater (Aythya marila) and lesser scaup (A. affinis). Prior to the implementation of the Canadian ban, 11% and 8% of greater and lesser scaup harvested in the LGL, respectively, had ingested lead shot. We collected greater and lesser scaup on the Canadian side of lakes Erie, Ontario, and St. Clair during autumn 1999 and spring 2000 to determine if lead shot ingestion declined 1 year after the ban in Canada. There were no intraspecific (lake, season, sex, or age) or interspecific differences in proportion of birds containing ingested shot. Overall, only 0.6% of birds (n = 4 of 722) contained lead shot and only 3.1% contained nontoxic shot. The low frequency of toxic relative to nontoxic shot ingestion suggests that shot may quickly become inaccessible to scaup on lacustrine areas of the Great Lakes. Thus, the risk of lead toxicosis to scaup migrating through the LGL appears low at this time. Pre- and postban differences in overall ingestion frequencies (8–11% vs. 3.7%) suggests that preban numbers may have been biased (elevated) because lead shot ingestion can increase harvest susceptibility. However, recent scaup dietary shifts may also have contributed to overall declines in shot consumption. Low postban lead shot ingestion may also be indicative of high hunter compliance with nontoxic shot regulations in Canada.

Lead contamination of seabirds harvested with lead shot — implications to human diet in Greenland

Lead contamination of seabirds from the use of lead shot in Greenland was studied in thick-billed murre hunted at Nuuk in November 1998. In each bird shot pellets were located and counted using X-ray. The birds were skinned and viscera, head, wings and legs removed, after which the carcass was cooked. The soup and breast meat were then analyzed for lead after removal of visible shot pellets. In the soup the lead concentration was quite low, mean 6.3 μg/l (95% confidence interval between 4.4 and 8.2 μg/l), whereas breast meat lead values have a mean of 0.22 μg/g (wet weight basis; 95% confidence interval between 0.10 and 0.36 μg/g). This is more than 10 times higher than in birds not killed with lead shot. We found no correlation between lead concentration measured and number of pellets recorded in the whole bird or in the soup or in meat. The study indicates that lead in the meat exists as small lead fragments, left during the passage of pellets through the breast. Because of inhomogeneous lead distribution in samples, the uncertainty of estimated lead concentration in breast meat is high. Based on this study, it is concluded that birds killed with lead shot are a significant source of lead, probably the most important single source, of the diet of many people in Greenland. We estimate an intake of 50 μg lead from eating one boiled murre with soup. In addition people will occasionally eat whole lead shot pellets which have documented health effects. An intake of 50 μg lead is about twice as much as the daily average lead intake from all dietary sources in Denmark, about 25 times the daily lead intake from other marine food items in Greenland, and about one-fourth of the accepted tolerable daily intake.

Lead Exposure in American Black Ducks after Implementation of Non-Toxic Shot

Lead poisoning from the ingestion of spent shotgun pellets has been recognized as an important disease of North American waterfowl since Bellrose's (1959) research >40 years ago. Nation-wide regulations banning the use of lead shot for waterfowl hunting were established in 1991. We compared the prevalence of lead exposure in American black ducks (Anas rubripes) wintering on 2 areas in Tennessee before (1986-88) and after the ban (1997-99) to assess the effect of the ban on lead shot on this species. Prevalence of elevated blood lead in black ducks declined by 44% from before (11.7% prevalence) to after (6.5% prevalence) the implementation of non-toxic shot. The reduction in lead exposure was pronounced in adult black ducks (from 14.3% to 5.3%). However, prevalence in lead exposure remained similar in juvenile black ducks (from 8.2% to 8.3%). Additional evidence from lead ingestion and lead poisoning mortality events also indicates that lead exposure has declined in waterfowl in the Mississippi flyway. We believe that lead ingestion will continue to decline, despite the persistence of lead shot in some wetlands. The impact of reduced lead exposure on waterfowl populations needs to be assessed.

Lead Shot Contamination in Edible Portions of Game Birds and Its Dietary Implications

ABSTRACT Lead exposure for First Nation Cree of the Mushkegowuk region (western James Bay area of northern Ontario, Canada) through ingestion of game hunted with lead shot is of concern and was investigated in this study. All lead concentrations in tissues of mammals (n = 45) and fish (n = 30) harvested in the Mushkegowuk Territory were at a level below the guideline set by Health Canada for human consumption of fish protein (i.e., <0.5 μg/g wet weight [ww]). No guidelines exist for game birds and mammals. However, livers of 2% (5/233) of the game birds collected showed lead concentrations> 0.5 μg/g ww. Moreover, 9% (33/371) of the gizzard (striated muscle) tissue samples obtained through harvesting of waterbirds and upland game birds employing lead shot, showed lead levels greater than the indicated arbitrary guideline. The presence of lead was shown by radiography and atomic absorption spectrometry to be the result of lead pellets and/or lead fragments being embedded in the striated muscle. People who consume any game species harvested with lead shot risk exposure to this metal by way of ingestion of tissue‐embedded lead pellets and fragments. Although Canada will be banning the use of lead shot for all migratory bird hunting in 1999, its extension to all game hunting should be considered because of potential human health concerns.

Spatial and temporal variation in lead levels related to body condition in the Mississippi Valley population of Canada geese.

Concern over lead poisoning led to progressive prohibition of toxic shot to harvest waterfowl in the 1980's. Nevertheless, waterfowl remain susceptible to ingestion of lead shot because illegal use continues and spent shot persists in soil and wetland substrates. While mortality due to lead toxicosis has subsided, sublethal effects may still affect survival and reproduction. We measured liver lead levels and body condition in 732 Canada geese (Branta canadensis interior) during July 1984 to April 1989 in southern Illinois (USA), east-central Wisconsin (USA), and northern Ontario (Canada). Although we sampled only individuals that were visibly healthy, 55 of 732 (7.5%) geese had elevated liver lead levels (> 2 ppm). Lead levels of 46 (6.3%) geese indicated subclinical poisoning (2-6 ppm) and 9 (1.2%) geese had lead levels indicative of clinical poisoning (> 6 ppm). A greater proportion of juveniles (14.3%) had elevated lead levels than did adults (6.0%), but there was no difference between genders. Lead levels were highest in autumn and winter in southern Illinois, but were low during nesting and summer, despite legal use of lead shot in northern Ontario during our study. Lead poisoning (> or = 5% of the population) was still evident during all seasons in juveniles, and during autumn and winter in adults, 5 to 10 yr after toxic shot was banned from areas where we collected geese during migration and winter. Elevated lead levels did not affect total body mass, lipid reserves, or mineral levels of geese we collected. Protein levels also were unaffected below 10 ppm, but there was evidence of decline at higher concentrations. Thus, it seems unlikely that lead exposure currently affects survival or reproduction of Mississippi Valley Population (MVP) geese via body condition, although other sublethal effects cannot be discounted.

Shot Prevalences and Diets of Diving Ducks Five Years after Ban on Use of Lead Shotshells at Catahoula Lake, Louisiana

Catahoula Lake, central Louisiana, is a RAMSAR Convention Wetland of International Importance and among the most important wintering and staging areas for waterfowl in North America. To evaluate exposure rates in Catahoula Lake waterfowl 5 years after a ban on use of lead shot, we determined the prevalence of ingested shot and diets of canvasbacks (Aythya valisineria) and lesser scaup (A. affinis) salvaged from commercial fishing nets in winter 1992-93. Plant material composed >77% of the midwinter diet of canvasbacks. Consumption of belowground plant material (e.g., chufa flatsedge [Cyperus esculentus] and arrowhead [Sagittaria spp.] tubers) exceeded 47% in 1992-93, but was lower than in 1987-88. Male lesser scaup fed almost exclusively on plant material, especially bearded sprangletop (Leptochloa fascicularis) and millet (Echinochloa spp.). Prevalence of ingested lead or steel shot was similar in canvasbacks (38%) and lesser scaup (34%) in spite of differences in foraging behavior, suggesting that ducks actively selected shot as grit. Shot (lead or steel) prevalence in diving ducks at Catahoula Lake was similar in winters 1987-88 and 1992-93, but the proportion of birds with lead in their gizzards was greatly reduced in 1992-93 (6%) compared to 1987-88 (27%). Because ingestion of lead shot deposited in wetlands prior to steel shot regulations remains a problem at some sites, we suggest that provision of nontoxic grit may serve to reduce lead shot prevalence in waterfowl at contaminated sites.

Settlement Rate of Lead Shot in Tundra Wetlands

Several species of breeding waterfowl have been shown to be exposed to lead shot on the Yukon-Kuskokwim (Y-K) Delta, Alaska. I seeded experimental plots with number 4 lead shot to determine the settlement rate of shot in wetland types commonly used by foraging waterfowl. I resampled plots for 3 years, using a suction dredge to remove sediment in 4-cm layers. There was no consistent change in the proportion of shot recovered in the 0-4-cm layer among years or habitat types. My results suggest lead shot is available to feeding waterfowl for many years, and that exposure of waterfowl to lead poisoning will likely occur for >3 years after the use of lead shot is curtailed.

Lead Pellet Ingestion in First Nation Cree of the Western James Bay Region of Northern Ontario, Canada: Implications for a Nontoxic Shot Alternative

Subsistence hunting for Cree of the western James Bay region of northern Ontario, Canada, is a way of life. In this study, it is shown that ∼15% of the radiographic charts examined had evidence of pellets contained in the gastrointestinal system, intraluminally, and/or in the appendix. It is assumed that the consumption of wildgame with lead shot embedded in the tissue was the source of the pellets. Because the presence of lead shot in the human gastrointestinal tract appears to increase the body burden of lead and considerable evidence is available on the occurrence of lead poisoning in waterfowl due to the ingestion of lead pellets,it is suggested that the use of lead shot should be discontinued nationwide in Canada. Although bismuth/tin shot has been growing in appeal because of several recent waterfowl studies demonstrating its nontoxic nature, caution is advised because of the uncertainty about the toxicity of bismuth in humans, especially when consumed as whole pellets or fragments in wildmeats. We maintain that the nontoxic alternative of choice at this time is steel shot.

Preventing lead toxicosis of European waterfowl by regulatory and non-regulatory means

SummaryMany years of waterfowl hunting have added thousands of tonnes of lead shot to European wetlands. Effective and non-toxic substitutes for lead shot have been developed and are commercially available throughout Europe, but few nations (Denmark, Finland, Norway and the Netherlands) have statutory requirements for their use. Governments can induce hunters to use non-toxic shot by regulatory measures and/or non-regulatory steps, but economic incentives to increase the affordability of lead-free shot have never been used by any nation and might be politically inappropriate. Educational programmes to increase the hunting public's understanding of the poisoning problem, and to provide accurate information on the non-toxic shot, are the best long-term way for governments to focus their spending and induce change, whether on a voluntary or regulated basis. Each of the six nations which has moved to end lead poisoning of waterfowl has adopted a regulatory approach, but these nations have acted independently of each other, and yet the use of non-toxic shot should apply to all countries of a flyway.Several European treaty and policy precedents could form the basis of a pan-European regulation requiring the use of non-toxic shot. A proposal to eliminate the use of lead shot in wetlands has been made under the Bonn and Bern Conventions. An European Union-USA proposal to reduce the use of different categories of lead under an Organization of Economic Cooperation and Development Council Act has been made, but has deleted an earlier recommendation that lead shot be included. The substitution of lead shot by nontoxic alternatives is also consistent with the European Council Directive on the Conservation of Wild Birds of 1979. The passing of a European Council regulation, stipulating the minimal acceptable standards for shot used for waterfowl hunting, is seen as the most effective way to remediate this transboundary toxic problem. This type of action by the European Union, while recognizing the Principle of Subsidiarity, would still allow other member states to enact more rigorous legislation pertaining to the use of lead shot within their jurisdiction, as have Denmark and the Netherlands. Although responsibility to enact and enforce a European Council regulation is the prerogative of each member state, a single regulation would promote consistency of action amongst all states.

Lead shot ingestion and lead poisoning of magpie geese anseranas semipalmata foraging in a Northern Australian hunting reserve

Sediments at Howards Springs Hunting Reserve in tropical Northern Territory have accumulated high densities of lead shot (330 000 shot ha −1), most of which is at depths (<20 cm) accessible to foraging magpie geese Anseranas semipalmata. Mean shot density is approximately 9% of density of sedge Eleocharis dulcis tubers, a favoured dry-season food which overlaps with shot in size. Large quantities of grit are available on the fringes of the swamp, but densities of the larger, shot-sized items (> 2 mm) that appear to be preferentially ingested or retained in gizzards are sometimes absent in areas where magpie geese forage. Lead shot are frequently ingested. Over two years 21·4% of a sample of mobile birds ( n = 103 ) had ingested shot in their gizzards. In 1989, 45·2% (n = 65) showed lead concentrations in their livers, indicating lead exposure. However, few birds had accumulated high concentrations of lead in wingbones, suggesting that repeated sublethal exposures are uncommon. We suggest that the combination of high shot ingestion rates and limited recurrence of exposure implies high mortalities from lead toxicosis. This conclusion is supported by the presence of substantial numbers of incapacitated lead-poisoned birds at Howard Springs and other wetlands in the Darwin region. If criteria developed in the USA were applied, these observations would justify immediate prohibition of the use of lead shot at Howard Springs. We discuss steps to inhibit exposure of waterbirds to existing lead shot deposits following a conversion to steel shot.

The use of lead shot for protection from gamma radiation.

Cavity walls filled with small lead shot may safely be used instead of solid lead, at least at thicknesses above 1·4 in., for personnel protection against γ rays. They are not suitable for shielding fixed objects such as photographic material. The diameter of the lead shot should not be greater than the effective diameter of the source.

Errors in Microweighing Due to the Use of Lead Shot in Tares

Errors in Microweighing Due to the Use of Lead Shot in Tares