CVMA-ACMV

Use of Lead Fishing Sinkers and Lead Shot in Canada – Position Statement

April 4, 2014

Position

The Canadian Veterinary Medical Association (CVMA) opposes the use of lead fishing weights and lead shot because of the direct and indirect toxicity they may induce in wildlife.  The CVMA strongly supports the development and use of non-toxic materials for hunting and angling purposes.

Background

  1. In Canada, lead was one of the first substances to be added to the List of Toxic Substances (Schedule 1) in the original 1988 Canadian Environmental Protection Act (CEPA). 
  2. Lead toxicity has been well described in wildlife species, especially waterfowl and raptors, with historical annual losses estimated at 2.5 million birds in North America before bans were introduced (1).
    1. Swans and other waterfowl have been shown to ingest spent lead shot. Loons ingest lead fishing weights or jigs, mistaking it for food or grit while feeding at the bottom of lakes or ponds or in agricultural fields.   In some species, such as the common loon (Gavia immer), lead toxicity is the leading cause of mortality (1,2).
    2. Avian predators and scavengers, such as eagles, hawks, great horned owls, and condors, can be inadvertently poisoned after eating sick, dead, or crippled game birds or hunter-discarded carcasses of ungulates or rodents that contain embedded lead ammunition fragments (3−7). 
    3. Terrestrial bird species reported to ingest spent lead shot with subsequent toxicity include mourning doves (Zenaida macroura), ring-necked pheasants (Phasianus colchicus), northern bobwhite quail (Colinus virginianus), wild turkey (Meleagris gallopavo), American woodcock (Scolopax minor), and chukars (Alectoris chukar). These species may consume lead shot as they feed on seeds on the ground or when they ingest small stones as grit, especially in heavy hunting areas or areas in which high densities of lead shotgun pellets accumulate in soil and sediment (e.g., clay target shooting ranges) (6).
    4. Lead poisoning and elevated lead concentrations in tissues have been reported in waterfowl, perching birds, small mammals, and frogs at trap and skeet ranges (8).
  3. The clinical effects of lead poisoning are well-documented (1,7,9).
    1. Birds with lead poisoning often have physical and behavioural changes, including loss of balance and inability to fly. Even when overt signs of lead poisoning are not present, birds may still have trouble feeding, mating, nesting, and caring for young. 
    2. Acute toxicity can occur after the ingestion of a single lead sinker or lead-headed jig, and can result in the death of the bird within a few days. 
  4. Lead shot is stable in most soils and breaks down via oxidation very slowly, if at all (10, 11). In some areas, the amount of lead deposited in the environment from hunting and target shooting have led to classification of the surrounding soil as a hazardous waste (8).
  5. Canada has required that non-toxic (non-lead) shot be used: in national wildlife areas since 1995, in wetlands since 1997, for hunting most migratory game birds across the nation since 1999, and for upland game birds since 2012.
    1. Lead exposure in ducks in Canada has declined dramatically since non-toxic shot regulations were established (12). 
    2. In Canada it is now illegal to use or possess lead fishing sinkers and jigs in national parks and wildlife areas. 
    3. The use of lead shot is still legal for some upland game hunting, and for target shooting. 
  6. Partial bans are not as effective as full bans due to difficulties with enforcement and reduced incentive to produce non-toxic alternatives.
    1. The CVMA supports the educational programs of government agencies and interest groups that inform the public about the hazards of lead.
    2. Non-toxic alternatives such as bismuth, steel, tin, or clay can be used for fishing weights and shot, and their use should be promoted.

References:

  1. Rattner B A. History of wildlife toxicology. Ecotoxicology 2009;18:773-783.
  2. Scheuhammer AM, Norris SL. A Review of the Environmental Impacts of Lead Shotshell Ammunition and Lead Fishing Weights in Canada.  Canadian Wildlife Service Occasional Paper No. 88, 1995, 54 pp;  Available from:  http://publications.gc.ca/collections/Collection/CW69-1-88E.pdf Last accessed Sept. 13, 2013.
  3. Scheuhammer  AM, Money  SL, Kirk  DA, Donaldson G. Lead fishing sinkers and jigs in Canada: Review of their use patterns and toxic impacts on wildlife. Canadian Wildlife Service Occasional Paper no. 108, Environment Canada, Ottawa. 2003, 48 pp; Available from: http://www.collectionscanada.gc.ca/eppp-archive/100/200/301/environment_can/cws-scf/occasional_paper-e/n110/html/publications/AbstractTemplate.cfm@lang=e&id=1031 Last accessed Sept. 25, 2013.
  4. Kendall RJ, Stansley W, Leighton F, et al.  An ecological risk assessment of lead shot exposure in non-waterfowl avian species: Upland game birds and raptors. Environmental toxicology and chemistry 1996; 15: 4-20.
  5. Fisher IJ, Pain DJ, Thomas VG.  A review of lead poisoning from ammunition sources in terrestrial birds. Biol Conser 2006;131:421-432.
  6. Hunt WG, Burnham W, Parish CN, Burnham KK, Mutch B, Oaks JL. Bullet fragments in deer remains: Implications for lead exposure in avian scavengers. Wildlife Society Bulletin  2006;34:167-170.
  7. Church ME, Gwiazda R, Risebrough RW, et al.  Ammunition is the principal source of lead accumulated by California condors re-introduced to the wild.  Environ Sci Tech 2006;40:6143-6150.
  8. Hui CA. Lead distribution throughout soil, flora, and an invertebrate at a wetland skeet range. J Toxicol Environ Health A. 2002;65:1093-1107.
  9. De Francisco N, Troya JR,  Agüera EI. Lead and lead toxicity in domestic and free living birds. Avian Pathology 2003;32:3-13.
  10. Pattee OH, Pain DJ. Lead in the environment. In: Hoffman DJ, Rattner BA, Burton Jr, GA, Cairns Jr, J, eds. Handbook of Ecotoxicology. 2nd Ed. Boca Raton, Florida: Lewis Publishers, CRC Press LLC, 2003:373-408.
  11. Henny  CJ.  Effects of mining lead on birds: A case history of Coeur d’Alene Basin, Idaho. In: Hoffman DJ, Rattner BA, Burton Jr, GA, Cairns Jr, J, eds. Handbook of Ecotoxicology. 2nd Ed. Boca Raton, Florida: Lewis Publishers, CRC Press LLC, 2003:373-408.
  12. Stevenson  AL, Scheuhammer  AM,  Chan HM.  Effects of lead shot regulations on lead accumulation in ducks in Canada.  Archives Environ Contam Toxicol 2005;48:405-413.

Revised July 2013