Lead Contamination of Waterfowl in Tasmania by Ingestion of Shotgun Pellets From Duck Shooting.

Abstract

Shallow-water sediments in duck-shooting areas were sampled to assess availability of shot pellets to foraging waterbirds by determining pellet densities and relating settlement behaviour to particle size composition. Sediments dominated by smaller particle sizes were found to inhibit pellet settlement below the surface layer. Blood samples were obtained from black swans (Cygnus atrata) and more than 17% had elevated lead concentrations. A small number of gizzards from Pacific black ducks (Anas superciliosa) held no pellets, but approximately 50% of livers and bones examined showed elevated lead concentrations. Alternative sources of lead pollution were considered and water and sediment sampling was carried out near the closest highway, but lead concentrations were very 1~w. The lead residues found in birds, and pellet densities in sediments, were broadly similar to those reported for areas with documented lead pellet contamination problems outside Tasmania. This indicates the existence of a lead pellet problem requiring remedial action. Options for this are briefly considered, as is the likelihood of other species being contaminated by direct ingestion of pellets, or indirectly by predation.