Ten years of PFOS and PFOA human biomonitoring in Italy: Exposure levels and determinants of exposure

Per- and polyfluoroalkyl substances (PFAS) are industrial chemicals widely diffused in the environment and associated with toxic effects on humans. They became a global issue because of their environmental mobility and persistence. Control measures have been adopted to reduce their environmental presence and human exposure.

Human biomonitoring studies have been conducted worldwide to estimate human exposure to these chemicals and to identify determinants of exposure, in order to provide indications to refine regulatory policy.

In this paper, we studied concentrations of two legacy PFAS, Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), in human serum. Serum samples were collected in Italy between 2007 and 2017 together with information on characteristics and lifestyle of the study participants. We applied univariate and multivariate statistical analyses to the resulting database to identify major determinants of PFAS exposure over time and in different exposure scenarios. PFOA concentrations ranged over four orders of magnitude, with a median value of 2.4 ng/mL and PFOS concentrations ranged over three orders of magnitude with a median value of 4.6 ng/mL. We identified exposure scenario and sex as the major factors in determining PFAS concentrations. In subjects at background PFAS exposure, we identified as other relevant determinants age, geographical area, degree of urbanization, level of education and skill level in occupation. A declining time-trend was observed for PFOA but not for PFOS.

This study provided information about determinants of PFOA and PFOS human exposure in Italy. Results can support defining measures to limit future human exposure to these persistent contaminants.