| Summary: | Environmental pollution with metals in large marine raptors is not a well-studied area, besides for lead poisoning from ammunition. There is a great need for monitoring the evolving trends after several international environmental treaties and restrictions on metal production have been enacted. In this study, two sampling locations (Smøla archipelago and Steigen archipelago) and two sampling years (2015 and 2016) provided samples for analyzing internal exposure of white-tailed eagle (Haliaeetus albicilla) nestlings to 13 essential and non-essential metals. Arsenic (As), calcium (Ca), cadmium (Cd), copper (Cu), iron (Fe), mercury (Hg), potassium (K), magnesium (Mg), manganese (Mn), molybdenum (Mo), sodium (Na), selenium (Se) and zinc (Zn) were analyzed in the whole blood of 47 nestlings using inductively coupled plasma mass spectrometer (ICP-MS). The differences between the two study sites and the two years were analyzed using principal component analysis (PCA) and (generalized) linear models. The results show that three metals (Hg, Mg and Mo) were significantly different between Smøla and Steigen when the two years were pooled together. In all cases, the levels were higher in Smøla compared to Steigen. Only Na showed significant differences between 2015 and 2016 when the data from the two locations were pooled together. The effect of diet, trophic level and sex on metal concentrations were also studied. There was no significant difference in any of the 13 metals between sexes. Diet and/or trophic level were found to be significant factors influencing the concentrations of As, Fe and Se. The potential effect of five metals (As, Cd, Cu, Hg and Zn) on metallothionein (MT) induction was also studied using a commercial ELISA assay. The MT concentrations ranged from 4.98 to 10.78 ng/ml plasma with a mean concentration of 7.73 0.27 ng/ml and were not significantly influenced by any of the five metals. In addition, MT induction was investigated for potential influence by biological factors (sex and age). However, no significant influence was found. Overall, the present study showed that concentrations of essential and non-essential metals in Norwegian white-tailed eagle nestlings are mostly influenced by location (industrialized vs. isolated area), diet (marine vs. terrestrial based) and trophic level.
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