Presence of per- and polyfluoroalkyl substances in untreated leachate from regional municipal waste landfills: A first assessment for Bulgaria

Bulgaria is lagging behind in its investigation of per-and polyfluoroalkyl substances (PFAS) and consequently in its contribution to the global database and knowledge.This study constitutes the first assessment of PFAS in untreated leachate from regional landfill sites, which are a customary source of PFAS to the environment.A total of ten landfill sites, selected to represent a range of characteristics, were analysed.The requisite chemical analyses were meticulously conducted in an accredited scientific laboratory in Rome, Italy (Acea Infrastructure SpA).Utilising state-of-the-art instrumentation such as liquid chromatography-mass spectrometry (LC-MS/MS), along with a comprehensively formulated analytical procedure tailored to the study's specific needs, ensured the highest standards of scientific rigor.The results reveal that merely eight out of the thirty PFAS analysed exhibited concentrations above the limit of quantification (LOQ).It was found that the total PFAS concentration (i.e. the sum of the PFAS that were determined) varied between a minimum of 1.1 g/L and a maximum of 14.0 g/L between the landfills.This range falls within the reported values in the scientific literature for other landfills internationally.The majority of the identified PFAS belonged to linear, short-chained perfluoroalkyl acids (PFAAs).The most prevalent PFAAs with a carboxyl group were perfluorohexanoic acid (PFPHxA; C6), detected in nine landfills at concentrations ranging from 0.9 to 5.0 g/L, perfluoropentanoic acid (PFPeA; C5), detected in seven landfills landfills at concentrations ranging from 0.6 to 1.7 g/L, and perfluorobutanoic acid (PFBA; C4), detected in six landfills landfills at concentrations ranging from 0.4 to 3.0 g/L.The predominant PFAA with a sulfonate group was perfluorobutane sulfonic acid (PFBS; C4), which was detected in eight landfills landfills at concentrations ranging from 0.8 to 8.0 g/L.The study also provides an overview of the potential environmental and human health implications of the short-chain PFAS, drawing on a review of international literature.As the first investigation of its kind in Bulgaria, this research contributes to the understanding of PFAS contamination in landfill leachate and highlights the need for further studies to assess associated risks.