Toxicity of experimental lead-iron shot versus commercial lead shot in mallards

The toxicity of an experimental lead-iron shot containing 38.1 percent lead was compared with commercial lead shot in mallard ducks (Anas platyrhynchos) fed corn for 14 weeks. Significantly higher mortality occurred in ducks dosed with commercial lead shot compared to ducks given lead-iron shot containing comparable amounts of lead. Loss of body weight was indicative of the difference in toxicity of the 2 types of shot. Mortality was dose related in ducks given commercial lead shot; one #8 shot (73 mg lead) caused 35 percent mortality with higher amounts of lead causing 80 to 100 percent mortality. Ingestion of up to 2 #4 lead-iron shot (111 mg lead) caused no significant weight loss and only 5 percent mortality. However, ducks dosed with 5 lead-iron shot suffered 45 percent mortality and those given 16 shot 50 percent mortality.