Osteoderms of estuarine crocodiles record their enhanced Pb exposure in Kakadu National Park

Abstract

Pb exposure in wild crocodiles, as recorded in their dermal bones (osteoderms). Riverine habitats of the estuarine crocodile, Crocodylus porosus, in Kakadu National Park, northern Australia, have been exposed to anthropogenic Pb since the mid-1950s, due mainly to replacement of traditional spear by guns using lead ammunition for the hunting of wildlife by the Aboriginal owners. Resident crocodiles ingest waterfowl, flying foxes, and pigs killed or crippled by Pb ammunition, also commonly found in crocodile stomachs. Among 40 wild crocodiles sampled, the osteoderms from five residents of two intensively hunted habitats each had enhanced Pb (19-44 íg/g dry weight), relative to all others.