Levels of Selected Trace Elements in Crested Caracara (Caracara plancus) Nestlings Near Oil Production Plants in Southern Patagonia, Santa Cruz Province, Argentina.

Oil and gas extraction, refining, reforming and transport are important production activities mainly conducted in the Southern Patagonia region of Argentina. Several threats to natural ecosystems have been associated with this industry, most of them related to the increase in toxic metals and metalloids in the environment and biota. Birds of prey are widely used to assess metals and metalloids pollution in the environment. This study determined levels of selected trace elements including both essential and toxic metals in the blood of Crested Caracara (Caracara plancus) nestlings and evaluated relationships between the trace elements composition levels and the distance between nests and oil production plants and the prevailing wind in Southern Patagonia, Argentina. Pb, As, Zn, Se, Ni, Cu, Cr, Cd and V were determined by inductively coupled plasma-mass spectrometry. Two groups of trace elements were correlated according to the blood levels detected (As-V-Cr; Zn-V-Cr), suggesting a common source of exposure to these trace elements. The prevailing wind constituted a promising mechanism to explain an association between the oil pipe-derived trace elements and the exposure of nestlings. Nestlings showed elevated levels of As, Se, Cd, Ni and Zn, which were higher than reference levels reported for other raptor populations. These results indicate that nestling Crested Caracaras are exposed to toxic trace elements in Southern Patagonia. This is the first report of trace elements in the blood of Crested Caracara nestlings inhabiting Southern Continental Patagonia, Argentina, and provides baseline data of this contamination in this species.