Exposure and effects of emerging and legacy organic pollutants in white-tailed eagle (Haliaeetus albicilla) nestlings
MetadataShow full item record
- Institutt for biologi 
Due to long-range transport and high abilities for bioaccumulation and biomagnification, persistent organic pollutants (POPs) are ubiquitous in the environment. Following the ban and legislation of POPs, such as on polychlorinated biphenyls (PCBs), organochlorinated pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) by the Stockholm Convention, new and emerging compounds such as perfluoroalkyl substances (PFASs) and various flame retardants have been increasingly detected in the environment. In recent years, some PFASs have also been legislated (e.g. PFOS) or have been proposed for listing (e.g. PFOA) to the Stockholm Convention on POPs due to their persistency in the environment. Due to their apex trophic position, white-tailed eagle (Haliaeetus albicilla) nestlings are good sentinels of local environmental pollution. The nestlings are exposed to maternally deposited pollutants during development in the egg and the exposure continues after hatching through their dietary intake. Adult white-tailed eagles are mostly resident in their breeding areas, thus the pollutant burdens of their eggs and nestlings reflect contaminant levels in local prey. White-tailed eagles are protected by law in several European countries and Norway has one of the largest resident populations of white-tailed eagles. Recent studies have reported PFASs to exceed concentrations of other legacy POPs (PCBs, OCPs and PBDEs) in Norwegian white-tailed eagle nestlings, and thus required closer attention. The overall aim of this thesis was to use non-destructive samples, such as plasma, feathers and preen oil, to investigate levels and physiological effects of emerging and legislated organic pollutants in white-tailed eagle nestlings. Samples were collected over two consecutive years (2015 and 2016) at two locations in Norway, Smøla in Møre og Romsdal and Steigen in Nordland. White-tailed eagle nestlings from Smøla and Steigen had generally low concentrations of PCBs, OCPs, PBDEs, PFASs, novel brominated and phosphorous flame retardants (NBFRs and PFRs, respectively) and dechlorane plus isomers (DPs). The plasma concentrations of legacy POPs were significantly and positively correlated with their corresponding feather and preen oil concentrations, which indicated the suitability of all these matrices for environmental monitoring of legacy POPs. Yet, plasma samples appeared to be more suitable to investigate internal concentrations of PFASs, NBFRs, PFRs and DPs. The general concentration pattern observed in plasma was PFASs > PCBs > OCPs > PBDEs, while PFRs, NBFRs and DPs were mostly below detection limits. Significant temporal and spatial variation were observed for the investigated pollutants and physiological parameters. Year and location differences influenced the PFASs concentrations, as significantly higher PFASs concentrations were observed in nestlings from 2015 than those from 2016, and in nestlings from Steigen than from Smøla. Yet, most of the variation of both legacy POPs and PFASs was explained by the age and diet of the nestlings. Significant statistical relationships were detected between plasma concentrations of pollutants and thyroid hormones, stress levels (corticosterone), prealbumin and blood clinical-chemical parameters reflecting liver and kidney function in the nestlings. However, as all physiological variables were within ranges previously reported for seemingly healthy and free-living birds of prey, the nestlings of the present thesis appear to be in good health, despite their pollutant burdens. Nevertheless, it cannot be ruled out that exposure to higher pollutant burdens may have a greater potential to induce physiological effects in white-tailed eagle nestlings.