Effects of Urbanisation on the Levels of Heavy Metals in Eggshells of European Blackbirds (Turdus merula)

Abstract

Research was done to investigate to what degree the European blackbird (Turdus merula) sequesters a variety of metals differently in its eggs depending on the extent of urbanization of their nesting environment. The amounts of maternally deposited heavy metals in eggshells were investigated in two main habitat types: (1) Urban: Supposedly more polluted urban environment of a densely populated residential area as well as university campus. (2) Forested: Semi-natural woodland and a botanical garden, both situated adjacent to a suburban university campus, and can be considered less polluted due to their isolation from industrial activities and dense residential areas. Data are reported on four essential elements Al, Zn, Ca, Cu (all these four metals are involved in development of eggs and formation of eggshell or eggshell membrane), and apart from the above mentioned metals the following metals are also assessed in the eggshell samples: Ba, Bi, Cd, Co, Cr, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, S, Sr.