THE ECOTOXICOLOGY OF LEAD SHOT AND LEAD FISHING WEIGHTS

Lead shot ingestion is the primary source of elevated lead exposure an d poisoning in waterfowl and most other bird species. For some species (e.g. Common Loons, Gavia immer), lead sinker ingestion is a more fre quent cause of lead poisoning. In freshwater environments where recrea tional angling activity and loon populations co-occur, lead poisoning from ingestion of small (< 50 gram) lead sinkers or jigs accounts for 10-50% of recorded adult loon mortality, depending on the locations st udied. Lead shot ingestion occurs in waterfowl, and in a wide variety of non-waterfowl species, including upland game birds, shorebirds, rap tors, and scavengers. Where it has been explicitly studied in Canada a nd the US, lead poisoning mortality of bald (Haliacetus leucocephalus) and golden eagles (Aquila chrysactos) from eating prey animals with l ead shot embedded in their Tissues accounts for an estimated 10-15% of the recorded post-fledging mortality in these raptorial species. In a ddition to environments that experience hunting with lead shot, clay t arget shooting ranges, especially those in which the shotfall zones in clude ponds, marshes, lakes, dyers, beaches, or other aquatic-type env ironments, create a significant risk of shot ingestion and poisoning f or waterbirds. Metallic lead pellets deposited onto soils and aquatic sediments are not chemically or environmentally inert, although tens o r hundreds of years may be required for total breakdown and dissolutio n of pellets. Functional, affordable non-toxic alternatives to lead sh ot and sinkers are being currently produced, and additional such produ cts are being developed. Several countries have successfully banned th e use of small lead sinkers, and of lead shot for waterfowl and other hunting, also for clay target shooting, using a phasing-out process th at gives manufacturers, sellers, and users adequate time to adjust to the regulations.