| Summary: | Anthropogenic contamination is a wide-spread environmental problem. In addition to persistent, bioaccumulative and toxic legacy contaminants, emerging contaminants with unknown environmental behaviour are causing concern. Many contaminants biomagnify in food webs, meaning that highest concentrations of contaminants are found in the apex species. Trophic dynamics of contaminants may differ depending on the properties of the contaminant, environment, and species composing a particular food web. In this thesis, I examine the current state of metal and organohalogen contamination in the Finnish Baltic coastal food webs, focussing on three avian sentinel species: the white-tailed eagle (Haliaeetus albicilla), the great cormorant (Phalacrocorax carbo), and the common eider (Somateria mollissima). In Chapter I, I investigate whether nestlings of white-tailed eagles and great cormorants act as sentinels for metal contamination associated with acidic sulphate soils. Compared to the control areas, I find higher concentrations of aluminium and cobalt in white-tailed eagles and of copper and manganese in great cormorants from the acidic sulphate soil areas. These results indicate that acidic sulphate soils are a source of certain metals for white-tailed eagle and great cormorant nestlings; there are, however, differences in metal exposure between these species. In Chapter II, I study the trophic transfer of mercury (Hg) between the benthic and pelagic food chains of the Archipelago Sea food web. The rate of trophic magnification of Hg was higher in the pelagic food chain than in the benthic food chain when the homeotherm birds were excluded from statistical models. In Chapter III, I investigate organohalogen contamination in the Archipelago Sea food web. I find that several organohalogen compounds biomagnify in the food web. Concentrations were generally highest in bird species, particularly the white-tailed eagle. As with the Hg models, statistical fit of the trophic magnification models of organohalogen compounds ...
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