A study of the SOURCE-TO-SEA occurrence of poly- and perfluoroalkyl substances (PFASs) of emerging concern in Ireland

Perfluorinated compounds are ubiquitous. Approximately 4,700 PFAS have been identified to date. Some examples of these products include carpets, glass, paper, clothing, and other textiles, cookware, food packaging, electronics, and personal care products. PFAS have been used in industrial and consumer products since the 1950s due to their physical and chemical properties. PFAS molecules can include oxygen, hydrogen, sulphur, and/or nitrogen atoms, whereas perfluorocarbon molecules contain only carbon and fluorine atoms. Perfluorinated compounds (PFAS) contain a fully fluorinated hydrophobic linear carbon chain attached to one or more hydrophilic head groups. The carbon-fluorine bond is so strong that these chemicals do not degrade in the environment. They are often referred to as ‘forever chemicals’. Some PFAS have been linked to an increased risk of cancer, high cholesterol, reproductive disorders, hormonal disruption or endocrine disruption, and weakening of the immune system. Currently, two PFAS are restricted under the international Stockholm Convention on POPs and the EU POPs Regulation. PFOS (perfluoroctanesulfonic acid) and its derivatives have been restricted since 2009/2010. PFOA (perfluorooctanoic acid), its salts, and related compounds are also regulated as of 4th July 2020. Over the past decades, global manufacturers have started to substitute long-chain PFAS with shorter-chain PFAS or with non-fluorinated substances. This trend has been driven by the fact that the undesired effects of long-chain PFAS on human health and the environment were assessed and recognised first by scientists and authorities around the globe. However short-chain PFAS are now thought to have similar or other properties of concern such as fluorinated compounds like Gen X and ADONA. The combined effects of PFAS are not widely studied and relatively unknown. There is also little biological assessment currently done for drinking water and especially marine water. These are both resea