Bioaccumulation of legacy and emerging per- and polyfluoroalkyl substances in hydroponic lettuce and risk assessment for human exposure

Effects of Nitrogen Fertilizer Types on the Uptake and Translocation of PFAS and Metabolomic Activities of Hydroponically Cultivated Lettuce (Lactuca sativa)

Increasing evidence is showing that per- and polyfluoroalkyl substance (PFAS) replacing compounds are not as safe as they were assumed. This study investigated the plant uptake of two most prevalent PFAS, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic (PFOS) and their replacing compounds, hexafluoropropylene oxide dimer acid (HFPO-DA or GenX) and 6:2 chlorinated polyfluoroalkyl ether sulfonates (Cl-PFESAs) (6:2 Cl-PFAES) by hydroponically grown lettuce in the presence of different nitrogen fertilizers including ammonium sulfate ((NH4)2SO4), potassium nitrate (KNO3), and urea in a growth chamber. Interestingly, (NH4)2SO4 significantly increased GenX uptake in lettuce shoots by ∼108% and KNO3 increased the uptake of PFOS and 6:2 Cl-PFAES by 267% and 395%, respectively, suggesting that the nitrogen fertilizer type has a marked impact on the plant uptake of PFAS and that this impact was PFAS-dependent. Our results also showed that (NH4)2SO4 generally resulted in higher PFAS root to shoot transfer than the other two types of nitrogen fertilizers. Metabolomic analysis revealed that amino acids, nucleotides, and antioxidants are the major metabolites that were either significantly increased or decreased in the lettuce shoots. These results showed that nitrogen fertilization management can have a significant impact on PFAS plant uptake and transport, and the impact depends on the types of nitrogen fertilizer and PFAS compounds.

Research Progress in Current and Emerging Issues of PFASs' Global Impact: Long-Term Health Effects and Governance of Food Systems

Per- and polyfluoroalkyl substances (PFASs) are found everywhere, including food, cosmetics, and pharmaceuticals. This review introduces PFASs comprehensively, discussing their nature and identifying their interconnection with microplastics and their impacts on public health and the environment. The human cost of decades of delay, cover-ups, and mismanagement of PFASs and plastic waste is outlined and briefly explained. Following that, PFASs and long-term health effects are critically assessed. Risk assessment is then critically reviewed, mentioning different tools and models. Scientific research and health impacts in the United States of America are critically analyzed, taking into consideration the Center for Disease Control (CDC)'s PFAS Medical Studies and Guidelines. PFAS impact and activities studies around the world have focused on PFAS levels in food products and dietary intake in different countries such as China, European countries, USA and Australia. Moreover, PFASs in drinking water and food are outlined with regard to risks, mitigation, and regulatory needs, taking into account chemical contaminants in food and their impact on health and safety. Finally, PFAS impact and activities briefings specific to regions around the world are discussed, referring to Australia, Vietnam, Canada, Europe, the United States of America (USA), South America, and Africa. The PFAS crisis is a multifaceted issue, exacerbated by mismanagement, and it is discussed in the context of applying the following problem-solving analytical tools: the Domino Effect Model of accident causation, the Swiss Cheese Theory Model, and the Ishikawa Fish Bone Root Cause Analysis. Last but not least, PFASs' impacts on the Sustainable Development Goals (SDGs) of 2030 are rigorously discussed.