Poly- and Perfluorinated Alkyl Substances in the Atmospheric Aerosol From a Rural Area of the Italian PFAS Hotspot (Veneto Region)

Poly- and Perfluoroalkyl substances (PFASs) comprise a large group of more than 8.000 synthetic organic surfactants, of which only a limited number is known and analyzed. They have a wide range of industrial and commercial applications and are commonly found in a broad variety of industrial and consumer goods. The physico-chemical properties of PFASs are not yet known in detail and are widely debated. Nevertheless, they show a high water solubility, which makes water resources the principal medium for their environmental transport. From the toxicological perspective, their environmental persistence and bioaccumulative properties make the PFASs a threat for the ecosystems and human health. In 2013, a widespread PFAS contamination of surface, ground, and drinking waters was discovered in the Veneto Region (North-Eastern Italy), mainly caused by the RiMAr-Miteni S.p.A. industrial wastewaters. Active since the mid-‘60s, this chemical factory contaminated one of the largest underground aquifers in Europe. The inhabitants of the provinces within the so-called “PFAS Red Zone” were exposed, unbeknownst to them, to a PFAS contamination through drinking water for a long time, which led to high concentrations of these chemicals in citizens’ serum. Given the high resonance and impact of this environmental and health emergency, the PFAS levels in the Veneto Region are continuously monitored in inland freshwaters by the Veneto Regional Environmental Prevention and Protection Agency. Nevertheless, limited information is available in literature on PFAS levels in the atmospheric aerosol, a matrix still little investigated, even in this highly impacted area. This work was conducted in order to overcome the lack of data relating to the occurrence of PFASs in the atmosphere of the Veneto Region. Sampling was conducted in a rural area near the municipality of Roncade, in the Treviso province, using a using a low-volume aerosol sampler Skypost PM (TRC-Tecora S.r.l.), equipped with a sequential sampler that operates at a flow rate of 38.3 L min⁻¹. 76 aerosol samples were collected between 02/07/2021 and 12/01/2022. Analysis of a broad spectrum of PFASs (target compounds, their precursors and substitutes) was carried out by High Performance Liquid Chromatography coupled with tandem Mass Spectrometry (HPLC-MS/MS). The compounds detected most frequently were the fluorotelomer 6:2 FTS and PFOS, while those with the highest concentration were 6:2 diPAP (802 ± 591 pg m⁻³), Me-FOSAA (15 ± 10 pg m⁻³ ), Et-FOSAA (9 ± 8 pg m⁻³), and the new generation compound GenX (13 ± 12 pg m⁻³). It has been observed that the total monthly PFAS concentration in the particulate increases in the winter season, especially for the compounds that belong to the classes of Perfluorinated carboxylic acids (PFCAs) and Perfluorinated sulfonic acids (PFSAs). This evidence is related to the reduction of their volatility with the decrease in temperature. Furthermore, the total monthly PFAS concentration increases with increasing relative humidity during the sampling seasons. Generally, the concentration levels detected in this study for PFOA and PFOS are comparable with those reported in literature.