Wild Boar Livers as Indicators of Different Sources of Contamination by Per- and Polyfluoroalkyl Substances (Pfas) – Comprehensive Target Analysis and Top Assay

Abstract

The suitability of wild boar liver as bioindicator for per- and polyfluoroalkyl substances (PFAS) in terrestrial environment was investigated. Samples from 50 animals in three different areas associated with (1) contaminated paper sludges distributed on arable land (PS), (2) industrial emissions (IE) and (3) background contamination (BC) were analyzed for 66 PFAS, including legacy PFAS, novel substitutes and PFAS precursors.Total Oxidizable Precursor (TOP) assay was performed to determine the formation potential of PFAS from known and unknown precursors. The formation potential from precursors was highest at area PS, but generally low. In total, 31 PFAS were detected with site-specific contamination profiles. Mean total concentrations of the analyzed PFAS ranged from 120 (area BC) to 944 (area IE) µg kg−1 wet weight (ww). The legacy PFAS perfluorooctane sulfonic acid (PFOS) dominated at areas PS (426 µg kg−1) and BC (82 µg kg−1), and perfluorooctanoic acid (PFOA) at area IE (650 µg kg−1). Also, the compounds 4,8-dioxa-3H-perfluorononanoic acid (DONA) and hexafluoropropylene oxide dimer acid (HFPO-DA) – which are used as substitutes for PFOA – were determined in wild boar liver from area IE (15 and 0.29 µg kg−1, respectively) and in local soil (0.43 µg kg−1 and <0.80 µg kg−1). Demonstrated exemplarily for area IE, the pattern of perfluoroalkyl carboxylic acids in wild boar liver mirrors the contamination of the local soil. However, discrepancies were observed between the terrestrial and a bordering riverine ecosystem (suspended solids, chub filet). While samples from the riverine environment were better suited to monitor the contamination with very polar PFAS, e. g. TFA, wild boar livers were found to indicate contamination with PFAS – both historic and current – that are particularly problematic for human health. This study suggests that wild boar livers are suitable bioindicators for legacy, substitute and precursor PFAS in the terrestrial environment.

Keywords: Bioindicators in the terrestrial environment, Bioaccumulation of legacy PFAS, Emerging contaminants, Short-chain PFAS, Precursor potential