Exposure and effects of legacy and emerging organic pollutants in developing birds: laboratory and field studies

The production and use of persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCPs) has been strictly regulated. However, in the recent decade, the restriction of POPs has led to a rapid increase of unrestricted alternatives, such as emerging flame retardants and a large number of per- and polyfluorinated alkyl substances (PFASs), replacing the restricted perfluorooctane sulfonate (PFOS). Emerging contaminants have already been detected in wild birds and bird eggs, however, information on their fate and effects in birds is scarce, especially during the early life-stages. Therefore, the thesis aimed firstly to investigate the potential biotransformation and effects of three selected emerging contaminants in the avian embryo using egg injection studies. Secondly, the thesis aimed to investigate the exposure and potential effects of legacy and emerging contaminants in free-living birds of prey nestlings. Egg injection studies on Japanese quail and chicken eggs showed that the emerging flame retardant tris (1,3-dichloro-2-propyl) phosphate (TDCIPP) can be rapidly biotransformed by the avian embryo during the embryonic development. In contrast, the emerging flame retardant Dechlorane Plus (DP) and the emerging PFOS alternative F-53B showed a higher persistence and bioaccumulative potential in developing birds. A significantly decreased heart rate was measured in chicken embryos at embryonic day 20 when exposed to a low dose of PFOS (150 ng/g) and a high dose of F-53B (1500 ng/g). Additionally, an increased relative liver weight was measured in one-day old hatchlings exposed to the highest dose of F-53B (1500 ng/g egg). In the field studies, plasma, preen oil and body feathers of northern goshawk (Accipiter gentilis) nestlings from two Norwegian counties (Trøndelag and Troms) were sampled. Emerging flame retardants, including TDCIPP and DP, were only detected in a few samples and F-53B was not detected at all in the goshawks. However, in feathers, phosphorus flame retardants (PFRs), including TDCIPP, showed higher concentrations than POPs and PFASs, most likely indicating external deposition of PFRs from the atmosphere onto the feather surface. Furthermore, POPs were the dominant contaminants in preen oil in accordance with the high lipid content of this matrix. PFASs were the dominant compounds in the plasma of goshawks, showing higher concentrations than POPs and suggesting recent and continuous exposure of goshawk nestlings to these contaminants. In addition, some blood clinical chemical parameters (BCCPs), including cholesterol and glucose, showed a significant association with POPs (paper IV). However, based on all investigated BCCPs, no significant organ impairment or nutritional stress was detected in the goshawk nestlings. Overall, the internal exposure of goshawk nestlings to emerging flame retardants was found to be low, compared to the concentrations of PFASs and POPs. However, the detected PFAS and POP concentrations were not expected to affect growth, reproduction or the general health of the nestlings. The thesis also showed that emerging contaminants such as DP and F-53B can be persistent and potentially toxic in young birds, indicating that a pro-active investigation of these contaminants is important.