Chemical element circulation in the trophic chains of different urban environments

Studies on element concentration in soils, plants, invertebrates and food, and body parts of synanthropic bird nestlings in polluted and unpolluted urban environments have been reviewed. Different ways of intake of elements by nestlings living in urban environments are presented. This required the determination of differences in element concentration in soils, plants, invertebrates and nestlings' food. It was considered that knowledge of these differences would allow establishment of the relationship between the element concentration in birds' bodies and the environment. Homeostatic mechanisms ensured Fe, Mg, Zn, Mn and Co accumulation in definite amounts in nestling tissues. Copper is mainly stored in soft tissues. These mechanisms made it possible for nestlings to accumulate Cd and Pb in soft tissues in small amounts compared with concentration of these elements in the environment. The majority of Cd and Pb taken in by nestlings was accumulated in bones and feathers. Higher concentrations of toxic heavy metals decreases the accumulation of physiological elements in the bodies of nestlings.