Beyond Molecules: In Situ Imaging Unveils DOM-Driven PFAS Nanoclusters with Mitigated Phytotoxicity

Area of Science:

• Environmental Chemistry
• Nanotechnology
• Plant Science

Background:

• Per- and polyfluoroalkyl substances (PFAS) environmental fate and toxicity are typically studied assuming a molecularly dispersed state.
• A widespread, overlooked nanoscale phenomenon involving PFAS has been identified, challenging existing paradigms.

Purpose of the Study:

• To investigate the formation of PFAS nanoclusters at the interface of dissolved organic matter (DOM).
• To elucidate the mechanism behind PFAS nanocluster formation and its impact on plant toxicity.

Main Methods:

• Utilized in situ atomic force microscopy (AFM) to visualize dynamic PFAS nanocluster formation.
• Probed intermolecular interactions between PFAS and DOM functional groups.
• Conducted plant exposure experiments with rice seedlings to assess phytotoxicity.

Main Results:

• PFAS dynamically form nanoclusters at the DOM interface, influenced by binding forces.
• A strong negative correlation exists between nanocluster size and abundance across various PFAS types.
• Nanoclustered PFAS showed significantly reduced uptake and mitigated phytotoxicity in rice seedlings compared to molecularly dispersed PFAS.

Conclusions:

• DOM-induced nanoclustering is a critical interface process governing PFAS bioaccessibility and environmental risk.
• This phenomenon offers a transformative perspective for PFAS environmental assessment and remediation strategies.