title: The importance of exogenous contamination on heavy metal levels in bird feathers. A field experiment with free-living great tits, Parus major.
abstract: Feathers have been used extensively as non-destructive biomonitors for heavy metal pollution. Birds excrete heavy metals into growing feathers during moult. After feather formation, the feathers become isolated from the rest of the body, suggesting that the feathers contain information of circulating heavy metal concentrations in the blood at the time of their development. However, heavy metal levels may change due to exogenous contamination, resulting in higher concentrations in feathers that are exposed most to exogenous conditions. We studied the effect of exogenous contamination in free-living adult great tits (Parus major) by measuring--within the same individual--the concentrations of twelve heavy metals (Ag, Al, As, Cd, Co, Cu, Fe, Hg, Mn, Pb, Tl and Zn) in three outermost tail feathers that were exposed to exogenous contamination for different periods of time. In particular, for each individual heavy metal levels in the removed left outermost tail feather were compared with levels in the regrown left and the right outermost tail feather, that were both removed 40 days after removal of the original left feather. This study revealed that, with the exception of mercury, the concentration of all heavy metals was significantly different among the three outermost tail feathers. Our results suggest that concentrations of most heavy metals build up with increasing age of the feather, indicating that exogenous contamination may be an important source of heavy metals in feathers. However, we found no significant differences in Hg concentrations and we found only small differences in Zn concentrations among tail feathers. Consequently, the concentrations of zinc and mercury in feathers are probably primarily due to endogenous deposition.
authors.affiliation: University of Antwerp, Campus Drie Eiken, Department of Biology, Universiteitsplein 1, B-2610 Wilrijk, Belgium. veerle.jaspers@ua.ac.be
authors.forename: Veerle
authors.initials: V
authors.lastname: Jaspers
authors.forename: Tom
authors.initials: T
authors.lastname: Dauwe
authors.forename: Rianne
authors.initials: R
authors.lastname: Pinxten
authors.forename: Lieven
authors.initials: L
authors.lastname: Bervoets
authors.forename: Ronny
authors.initials: R
authors.lastname: Blust
authors.forename: Marcel
authors.initials: M
authors.lastname: Eens
authors.forename: Jaspers
authors.initials: J
authors.lastname: Veerle
authors.forename: Dauwe
authors.initials: D
authors.lastname: Tom
authors.forename: Pinxten
authors.initials: P
authors.lastname: Rianne
authors.forename: Bervoets
authors.initials: B
authors.lastname: Lieven
authors.forename: Blust
authors.initials: B
authors.lastname: Ronny
authors.forename: Eens
authors.initials: E
authors.lastname: Marcel
mesh_terms: D000818:Animals; D004781:Environmental Exposure; D005241:Feathers / Q000737:chemistry*; D019216:Metals, Heavy / Q000032:analysis / Q000493:pharmacokinetics*; D015203:Reproducibility of Results; D020308:Songbirds
chemical_list: D019216:Metals, Heavy