Toxicity of Experimental Lead-Iron Shot versus Commercial Lead Shot in Mallards

Abstract

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 per- cent mortality. However, ducks dosed with 5 lead-iron shot suffered 45 percent mortality and those given 16 shot 50 percent mortality. J. WILDL. MANAGE. 42(1):32-39 Lead poisoning from ingested lead shot is still a major cause of mortality in water- fowl. A recent survey showed that the inci- dence of lead shot in gizzards ranged from 1.3 to 29.1 percent (White and Stendell 1977). They also reported a significant posi- tive correlation between frequency of lead shot in gizzards and lead residues in wing- bones. Considerable efforts are being made to develop nontoxic substitutes for lead shot. Toxicity studies using several types of shot have shown that lead-induced mor- tality is in proportion to the amount of lead present in the shot (Irby et al. 1967, Grandy