Heavy Metal Concentrations in Free-Living Southern Caracaras (Caracara plancus) in the Northeast Region of Brazil

Background: With the continuously increasing release of heavy metals in the environment, mostly from anthropogenic sources, there is a need to find ways of evaluating and managing the issuance of these contaminants and correct its damages. The birds being at the top of some food chains reflect the presence of metals in the environment, keeping this in perspective, raptors have been successfully used for heavy metals biomonitoring studies in the past. The purpose of this study was to identify and quantify cadmium (Cd), mercury (Hg), lead (Pb), copper (Cu), and chromium (Cr) in the feathers and livers of free-living southern caracaras, live and dead, from Recife, Pernambuco state, Northeast of Brazil.Material, Methods & Results: Sixty-two feathers from live and dead southern caracaras and 21 livers from dead southern caracaras were analyzed by atomic absorption spectrometry for Hg and by inductively coupled plasma optical emission spectrometry for Cd, Cr, Pb, and Cu. Concentrations of Cr and Cu elements were detected in all feather and liver samples analyzed from live and dead caracaras. There was no difference in the concentration of metals between feathers of dead and live caracaras: Pb (P = 0.3576), Cd (P = 0.0792), Cr (P = 0.5475), and Cu (P = 0.3603), but significant variation was observed for Hg (P = 0.0459). The highest concentrations of Pb (P < 0.0001) and Cr (P < 0.0001) were found in the feathers than in the liver. On the other hand, the highest concentrations of Cu were found in liver samples (P = 0.0011). No significant variation in the concentrations of Cd (P = 0.7770) and Hg (P = 0.3669) was found between feathers and liver samples.Discussion: Chromium, as well as Hg, and Cu have a high affinity for keratin, which may explain the higher concentrations of Cr in caracaras feathers in this research. Lead was detected in all liver samples analyzed. Elevated levels were also found in the feathers of dead (95.2%) and live (75.6%) caracaras. The presence of Pb may be due to external contamination by pollutants, such as fossil fuels. Higher concentrations of Hg were observed in dead caracaras feathers, this concentrations change during molting but are not affected by external contamination. Metals, such as Hg, and Cd, accumulate in organisms from different trophic levels, which may indicate that this contamination comes mainly from feed. Pearson’s coefficient here showed no correlation between metals from dead caracaras feathers and livers, although a