Evaluation of Pb and Hg levels in wild migratory water-birds nesting in different areas of Po Delta

Evaluation of Pb and Hg levels in wild migratory water-birds nesting in different areas of Po Delta. Alessandro Guerrini1, Giorgio Fedrizzi2, Alessandro Andreotti3, Luisa Iannone1, Paola Roncada1 1 Alma Mater Studiorum - Università di Bologna – Dipartimento di Scienze Mediche Veterinarie 2 Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna, Reparto Chimico degli alimenti – Bologna 3 ISPRA - Istituto Superiore per la Protezione e la Ricerca Ambientale, Via Ca' Fornacetta 9, 40064 Ozzano Emilia, Italy The use of fossil fuels as main energy resource led to metal emissions that spread all over the environment and contaminate ecosystems and food. This has resulted in even serious toxic effects, both in humans and animals. A characteristic feature of some metals is their pronounced biological accumulation and biomagnification in food chains. For these reasons, their monitoring in the environment should be constant over time. This study shows data on Pb and Hg levels in tissues of various species of wild migratory water-birds nesting in different areas of Po Delta. The sampling was carried out from May to July 2016. Analyses were performed according to the internal test method of the IZSLER by inductively coupled plasma mass spectrometry (ICP/MS). The two metals were found in most of the analyzed samples. The maximum levels of Pb were found in the natal down of nestlings (3.5515 mg/kg), and in feathers, femur and humerus of adult birds (5.2363, 15.469 and 12.9760 mg/kg, respectively). In adults the highest concentrations of Hg were found in feathers and liver (6.0144 and 6.1939 mg/kg, respectively) while in nestlings the highest level was found in down (4.9411 mg/kg). The differences between the average concentrations detected in adults and those measured in nestlings can be explained by chronic exposure to metals. This exposure is usually highest at the top of food chains in predatory species. Thus, the birds of prey may be suited for monitoring purposes, but their sampling may be difficult due to their low population densities and high mobility. Moreover, in the present study only birds dead of natural causes were used. In the future, the analysis of a higher number of samples will provide a more complete picture. Acknowledgments Authors greatly acknowledge Fabrizio Borghesi, Lorenzo Serra, Stefano Volponi and Alberto Altafini for their collaboration.