Avian developmental toxicity of perfluorochemicals: species sensitivity differences and mechanisms of action

Aims and project description

In studies of the toxicity of perfluoroktansulfonate (PFOS) in chicken embryos we have found a LOAEC for mortality of 3 mg/kg. The levels that have been determined in Baltic guillemot eggs are 1/3 of this concentration, which indicates that the margin of safety may be low. Other Nordic studies have detected high levels of PFOS and other perfluorinated chemicals in eggs of avian top predators. The large use of various PFCs will continue. This will lead to an increasingly complex exposure situation for PFCs in avian top predators. Since the early life stages are the most sensitive we want to increase the knowledge of PFCs developmental toxicity in birds. We want to study differences in sensitivity to a selection of relevant perfluorinated sulfonates and carboxylates in wild and domesticated birds. We also want to use microarray studies to elucidate mechanisms of action. The results will help identify the most critical mechanism of action of the PFCs, which will determine which chemicals can be combined in ecological risk assessments. The findings will allow development of PFC-specific biomarkers. Another goal is to develop species-specific structure-activity relationships for developmental toxicity. The following hypotheses will be tested:

1. Avian embryo development is affected by PFCs, and species have different sensitivity.

2. The PFCs act by a common mechanism of action.

3. Avian top predators are at the highest risk of being affected by PFCs.