Occurrence of Major Perfluorinated Alkylate Substances in Human Blood and Target Organs

Human exposure to perfluorinated alkylate substances (PFASs) is usually assessed from the concentrations in serum or plasma, assuming one-compartment toxicokinetics. To characterize body distributions of major PFASs, we obtained and extracted tissue samples from 19 forensic autopsies of healthy adult subjects who had died suddenly and were not known to have elevated levels of PFAS exposure. As target organs of toxicological importance, we selected the liver, kidneys, lungs, spleen, and brain, as well as whole blood. Samples weighing about 0.1 g were analyzed by liquid chromatography coupled to triple mass spectrometers. Minor variations in PFAS concentrations were found between the kidney cortex and medulla and between lung lobes. Organ concentrations of perfluorooctanoic sulfonate (PFOS) and perfluorononanoate (PFNA) correlated well with blood concentrations, while perfluorooctanoate (PFOA) and perfluorohexanoic sulfonate (PFHxS) showed more variable associations. Likewise, the liver concentrations correlated well with those of other organs. Calculations of relative distributions were carried out to assess the interdependence of organ retentions. Equilibrium model predictions largely explained the observed PFAS distributions, except for the brain. Although the samples were small and affected by a possible lack of homogeneity, these findings support the use of blood-PFAS concentrations as a measure of PFAS exposure, with the liver possibly acting as the main organ of retention.