ALS Product catalogues SOIL, SLUDGE and SEDIMENT | Page 26

PERFLUORINATED COMPOUNDS (PFC) As a result of the growth of the synthetic chemical industry over the last 50 years, many thousands of new fluorinated molecules have been synthesised and through various mechanisms, have become almost ubiquitous in the environment. A multitude of poly- and perfluoroalkyl substances (PFAS), valued for their ability to repel both water and oils, have been used for decades for diverse applications such as water repellent “outdoor” fabrics, stain resistant carpets, non-stick frying pans and firefighting foams. PFOS (perfluorooctane sulphonate) and PFOA (perfluorooctanoate) are the best known examples of PFAS. Their potential impact on human health has already been recognized internationally as they are extremely persistent, bioaccumulative and toxic. As a result, PFOS is restricted under the Stockholm Convention and classed as a persistent organic pollutant (POP), with PFOA being actively considered for inclusion. PFOS is also listed in the European Union Priority Substances Directive (2013/39/EU) with Environmental Quality Standards (EQSs) in fresh, surface water, coastal waters and biota. However, more recently, regulators’ in differing countries interest and concern has expanded to take in a much wider number of the PFAS now known to be present in the environment such as perfluorinated or polyfluorinated alkyl substances compounds (PFAS) which have entered the environment from aqueous film forming foam (AFFF) and multiple other products. Perfluorinated compounds do not break down or biotransform under natural conditions in the environment. Whereas, the polyfluorinated compounds are sometimes termed “precursors” as they can biotransform to form more simple Perfluorinated alkyl acids such as PFOA. As a result, there are significant analytical challenges to overcome when considering how to assess soil and groundwater contaminated with PFAS as there are multiple analytes to consider, not just PFOS and PFOA, with many of the perfluorinated compounds being of unknown composition. Routine analysis of these compounds is undertaken by Liquid Chromatography - Triple Quadrupole Mass Spectrometry (LC-QQQ). This analytical technique is very selective and sens