Hair analysis as a non-invasive method for assessing the exposure of mammals with different dietary habits to poly- and perfluoroalkyl substances

Background and Purpose: Poly- and perfluoroalkyl substances (PFASs) are persistent environmental pollutants found across various ecosystems. While human and domestic animal exposure to PFASs is well documented, data on wild terrestrial mammals remain scarce, particularly when using hair as a biomonitoring matrix. Hair appears particularly valuable for PFAS biomonitoring in wildlife, as it accumulates chemicals over time and reflects long-term exposure remaining intact after death. Despite this potential, very few studies have investigated PFAS accumulation in the hair of wild terrestrial mammals. This study aimed to assess the levels of selected PFASs in the hair of different wild mammal species with varying diets, using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Methods: Samples were collected between January and June 2023 in the Abruzzo region, located in central Italy. The study encompassed 58 adult individuals, belonging to three groups in term of feeding behaviour: 1) herbivores (n=23) including roe deer and red deer; 2) predators (n=25) including red fox, European badger and wolf; 3) omnivores (n=10) including wild boar. The PFASs analysed included perfluorobutanesulfonic acid (PFBS), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorohexanesulfonic acid (PFHxS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), linear and branched perfluorooctane sulfonic acid (L-PFOS and B-PFOS), perfluoropentanesulfonic acid (PFPeS), perfluoroheptanesulfonic acid (PFHpS), perfluoroundecanoic acid (PFUnDA) and perfluorododecanoic acid (PFDoDA). Quantification of analytes was conducted using LC-MS/MS, employing a Sciex Triple Quad™ 7500 system (Sciex, Framingham, MA, USA) operated in negative electrospray ionization (ESI-) mode. Descriptive statistics were applied to summarize the data. To compare PFAS concentrations among animals with different feeding behaviours, the non-parametric Kruskal-Wallis test was employed. Results: The levels of PFASs detected in this study varied significantly depending on both the specific compound and the mammalian species analysed. When considering all 58 hair samples collectively, the highest mean concentrations were observed for PFNA and PFOA. PFNA exhibited a mean ± SD of 0.309 ± 0.33 ng/g (median: 0.37 ng/g) and was detected above LOQ in 93.1% of samples. PFOA was present in 96.6% of samples (mean ± SD: 0.272 ± 146 0.51 ng/g; median: 0.15 ng/g). Significant inter-group differences were also observed for individual compounds. The clearest differences between predators and herbivores were noted in the case of L-PFOS and PFDoDA. Mean level of L-PFOS in predators was 0.291±046 ng/g (median 0.143 ng/g) and was statistically significantly higher (p<0.0001) than value noted in herbivores (mean 0.033±0.09 ng/g, median