Spatial and temporal variation of lead, cadmium, and zinc in feathers of great tit and blue tit nestlings in central

Abstract In this study, we examined heavy-metal con-centrations in feathers of nestling great tits Parus major and blue tits Cyanistes caeruleus at two different sites (urban parkland vs. deciduous forest) located in the Łódź agglomeration in relation to interyear variation. We found that tit species did not differ significantly in lead and cadmium concentrations. Zinc concentration was signifi-cantly higher in blue tits. We also found that lead and cadmium levels in blue tit nestlings and the level of lead in great tit nestlings were higher in the parkland site than in the woodland site. We explain habitat variation in heavy-metal concentrations in feathers of nestlings by different levels of contamination at study sites. For both tit species, significant variation in heavy-metal amounts accumulated by nestlings was found between years with the lowest value in a year with the lowest value of rainfall. We suggest that the interyear variation may be accounted for by differences in rainfall, thus influencing quantities of trace elements bioavailable in the environment. Urbanization and industrial processes exert a great influ-ence on environment, mostly by contributing large amounts of toxic trace elements. Therefore, an important task is to identify reliable methods to evaluate and monitor heavy-metal pollution. Living organisms provide useful data on the bioavailability and toxicity of metals and are good bioindicators (Burger 1993; Dauwe et al. 2002; Swaileh and Sansur 2006). The use of various species classified as bioindicators allows us to evaluate heavy-metal impacts on different types of environment. Furthermore, contamina-tion level may be monitored in time, thus giving an idea of past, current, and future condition of the ecosystem in which the organism lives. In addition, using organisms to monitor the presence of heavy metals in the environment provides accurate information on how they may affect physiological and behavioral processes (Holt and Mille