Perfluorooctanoic acid (PFOA) is a widespread environmental contaminant with known toxic effects on humans and animals, attracting significant scientific concern. Its proteinophilic nature has prompted research into its interactions with biological macromolecules, yet the role of specific molecules like amino acids remains underexplored. This study addresses this gap by conducting 48-hour acute toxicity tests on Daphnia magna, and utilizing fluorescence and infrared spectroscopy to investigate the interaction mechanisms involved between PFOA and L-tryptophan (L-Trp).
Results indicate that L-Trp presence in PFOA-contaminated water significantly reduces acute toxicity in D. magna. Optimal attenuation of toxic effects occurred at an L-Trp to PFOA ratio of approximately 0.5, indicating that one molecule of L-Trp binds with two molecules of PFOA. The study reveals that non-covalent interactions, particularly van der Waals forces and hydrogen bonds, are central to the L-Trp-PFOA complex formation. Additionally, hydrophobic effects at the indole group and electrostatic interactions between carbonyl and amine groups contribute to the complex. These interactions likely reduce PFOA’s toxicity by altering its bioavailability and/or distribution. While, this study provides insights into the reaction mechanism between L-Trp and PFOA, it also raises considerations regarding the reversibility of this interaction and its applicability to other per- and polyfluoroalkyl substances (PFASs).
| Date | 10 Dec 2024 |
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| Original language | French |
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| Awarding Institution | - École de technologie supérieure
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| Supervisor | Robert Hausler (Supervisor) |
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Verhille, M. (Author),
Hausler (Supervisor),
10 Dec 2024Student thesis: Master's thesis › Master in Engineering: Environmental Engineering