Perfluoroalkyl substances (PFASs) are widely utilized manmade chemicals. Their properties have made them highly appreciated in a variety of industrial and consumer product applications, including fire-fighting foams, hydraulic fluids, as well as in cookware and food contact papers.

However, some of the PFASs are highly persistent in the environment and their toxicological profiles are of concern. Voluntary and regulatory efforts have been taken to reduce the environmental levels of PFASs. These actions have resulted in a reduction of PFASs in human milk from Stockholm as presented in this thesis.

The radiosyntheses of ³⁵S-PFOS, ³⁵S-PFBS, and ¹⁴C-PFOA presented herein were applied for distribution studies in mice but also for solubility and adhesion experiments of common laboratory solvents and buffers. The radiosynthesis employed reactive Grignard reagents, perfluoroalkyliodides, and ³⁵S-sulfur dioxide or ¹⁴C-carbon dioxide. The distribution studies were performed with ³⁵S-PFOS on both pregnant mice and their offspring as well as on male mice. The mice were subjected to whole-body autoradiography and the tissues were analyzed by liquid scintillation counting. Liver and lungs were the target organs for ³⁵S-PFOS in the dams. The fetuses and pups had remarkable high levels of ³⁵S-PFOS in their lungs as well as in the brain. The male mice were given a high dose and a more environmental relevant dose of ³⁵S-PFOS. PFOS was transferred from the blood to the tissues as the dose increased.

In another study the distribution pattern of the shorter homologue PFBS was compared to PFOS. ³⁵S-PFBS was utilized and demonstrated a 5-40 fold lower tissue levels in comparison to PFOS.

The pharmacokinetic parameters determined for PFHxS in mice, rats, and monkeys will provide valuable insight in establishing a proper risk assessment for this compound. The study confirms the common species differences in serum elimination half-life that are associated with PFASs.