Dosing of adult pigeons with as little as one #9 lead pellet caused severe d-ALAD depression, suggesting potential adverse effects in wild populations Jeremy P. Holladay • Mandy Nisanian • Susan Williams • R. Cary Tuckfield • Richard Kerr • Timothy Jarrett • Lawrence Tannenbaum • Steven D. Holladay • Ajay Sharma • Robert M. Gogal Jr. Accepted: 8 August 2012 / Published online: 18 August 2012 Ó Springer Science+Business Media, LLC 2012 Abstract Avian wildlife species commonly ingest lead (Pb) spent shot or bullet fragments as grit or mistakenly as food. In previous studies in our laboratory and others, the toxicity varied based on the diet as well as type and quantity of Pb ingested. In the current study, domestic pigeons were gavaged with 1, 2, or 3 Pb pellets and then followed with weekly radiographs and blood physiologic endpoints for 28 days. Pellet retention decreased by roughly 50 % per week as pellets were either absorbed or excreted, except for week 4 where pellet number no longer was diminished. Size of retained pellets visually decreased over retention time. Birds dosed with a single #9 pellet showed mean blood Pb levels over 80 times higher than those of the controls, verifying Pb pellet absorption from the gut. A single Pb pellet also reduced plasma d-amino- levulinic acid dehydratase (d-ALAD) activity by over 80 % compared to controls, suggesting the potential for population injury in Pb pellet-exposed pigeons. Keyword Lead Á Avian Á Ventriculus Á Retention Á d-ALAD Introduction Public, private, and federally owned shooting ranges and hunting sites as well as military training grounds all contain spent lead (Pb) shot which can be harmful to wildlife species (Buekers et al. 2009; Rattner et al. 2008). Although newer data do not exist, estimates from the 1990s show 80,000 tons of Pb to be released in the United States each year by recreational hunters alone (Craig et al. 1999). Further, Pb fragments or pellets were detected within the digestive tract of both migratory and nonmigratory avian species near these sites after having been ingested for grit or possibly mistaken for food (Duggan and Dhawan 2007; Bennett et al. 2007). Mateo et al. (2001) reported that 32 % of white-headed ducks (Oxyura leucocephala) sampled from a wetland waterfowl hunting area had ingested Pb shot. Kendall and Scanlon (1982a, b) likewise documented Pb in the blood in mourning doves and rock doves in Virginia. Schulz et al. (2006) conducted a controlled acute Pb toxicity study on mourning doves by dosing 157 birds with 2–24 Pb pellets. These authors reported a strong correlation between sur- vival and the number of pellets administered. However, the effects of a single pellet were never determined, and may represent the majority of environmentally-exposed birds. Further, there is no clear consensus on the effect of acute exposure to a single Pb pellet within avian species. Data showing Pb pellet or fragment retention time in birds remain limited. Kerr et al. (2010) recently found Northern Bobwhite quail to have a relatively short J. P. Holladay Á M. Nisanian Á R. Kerr Á T. Jarrett Á S. D. Holladay Á A. Sharma Á R. M. Gogal Jr. (&) Department of Biosciences and Diagnostic Imaging, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA e-mail: rgogal@uga.edu S. Williams Poultry Diagnostic and Research Center, Department of Population Health College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA R. C. Tuckfield Savannah River Ecology Laboratory, University of Georgia, Athens, GA 30622, USA L. Tannenbaum U.S. Army Institute of Public Health, Aberdeen, MD 21010-5403, USA 123 Ecotoxicology (2012) 21:2331–2337 DOI 10.1007/s10646-012-0989-x