Patterns of environmental lead exposure in waterfowl in Eastern Canada

• Published in: Ambio 1996-02, Vol.25 (1), p.14-20
• Main Authors: Scheuhammer, A M, Dickson, K M
• Format: Article
• Language: English
• Subjects: Anas platyrhynchos; Anas rubripes; aves acuaticas; Aythya collaris; Bones; Brackish; canada; canard; caza; chasse; contaminantes industriales; Ducks; Fowling; Freshwater; Gizzard; Hunting; industrial pollutants; Ingestion; Lead; Metals mining; oiseau aquatique; pato; plomb; plomo; Poisoning; polluant industriel; Waterfowl
• ISSN: 0044-7447; 1654-7209

Wing bones from several thousand young-of-the-year ducks from across Eastern Canada were analyzed for lead content, and the geographical pattern of elevated lead concentrations was determined and compared with the presence of activities known to cause environmental contamination with lead, namely waterfowl hunting, nonferrous metal mining/smelting, and urban/industrial development. Results indicate that ingestion of spent lead-shot pellets from waterfowl hunting is probably the primary source of elevated lead exposure for wild ducks in Canada. Proximity to metal mining sites, especially gold, silver, and copper/zinc mines, was also a significant correlate, accounting for about a quarter of the total area characterized by a high incidence of elevated lead exposure. In areas where significant waterfowl hunting occurs, results indicate that rather than a few small local sites of high lead exposure, a rather widespread pattern of elevated bone-lead in young-of-the-year ducks exists. These results, combined with other considerations, have caused Canada to abandon its nontoxic shot-zoning approach in favor of a broader ban on the use of lead shot. Beginning in 1997, all migratory game-bird hunting in Canada will require the use of nontoxic shot.