Concentrations of eight essential elements (Ca, Co, Cr, Cu, Fe, Mn, Ni and Zn) and three toxic metals (Al, Pb and Sr) were measured in various tissue samples from African whitebacked (Pseudogyps africanus), Cape griffon (Gyps coprotheres) and Lappetfaced (Torgos tracheliotos) vultures in different regions of South Africa. Blood samples from live African whitebacked vultures were taken from nestlings from two breeding populations, adults from a wildlife reserve and immature birds held in captivity. With the exception of Sr and Mn, concentrations of the majority of metals differed between two or more of the sampling localities and between captive and wild individuals. Birds from Moholoholo had the highest overall blood metal concentrations, while concentrations in birds from Dronfield were the lowest, as can be expected for nestlings and adults respectively. Fatty tissues and bones had the highest values of metal accumulation, especially Sr, and this is congruent with results from previous studies. It was concluded that most concentrations compared well with those reported for other avian species, but concentrations of Cr, Ni and Pb in the dead vultures were generally above values characteristic of heavy metal poisoning. The values reported for each of two wild populations of P. africanus nestlings and adults, and for two other vulture species could serve as base-line data for future comparative studies.
Selected mineral and heavy metal concentrations in blood and tissues of vultures in different regions of South Africa
Author: E. van Wyk, F.H. van der Bank, G.H. Verdoorn and D. Hofmann
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