Great and blue tit feathers as biomonitors for heavy metal pollution

Abstract

In this study we investigated the concentration of two non-essential (Cd and Pb) and two essential (Cu and Zn) heavy metals in the outermost tail feathers of great ( Parus major ) and blue tits ( Parus caeruleus ). Cd, Cu, Pb and Zn concentrations in the feathers of great tits were significantly higher at a polluted site (near a metallurgic factory) than at a reference site (situated 4 km east of the polluted site). Blue tits at the polluted site had significantly higher Cd, Cu and Pb concentrations in the outermost tail feathers than blue tits from the reference site. Apart from Pb concentrations that were significantly higher in blue tits than in great tits, no significant interspecific differences in metal levels occurred. Although feathers have been used intensively as a biomonitoring tool, few studies have addressed the effect of both age and gender on the metal accumulation. We did not observe any significant differences in the metal levels in great tit feathers between the two studied age classes (individuals of 4–9 months old and individuals older than 16 months). Cd, Cu and Pb levels did not differ significantly between male and female great tits. The Zn concentration however, was significantly higher in males than in females. We examined correlations between concentrations in the outermost tail feather and the liver, kidney, muscle, innermost tail feather and the second and seventh primary in great tits. For the essential elements Cu and Zn we found no significant correlations between levels in the outermost tail feather and levels in any of the internal tissues examined. Cd and Pb concentrations in the outermost tail feather, on the other hand, were significantly positively correlated with levels in the liver, kidney and muscle. We suggest that feathers of great and blue tits may be useful biomonitors for local contamination with heavy metals.