Per- and polyfluoroalkyl substances (PFAS) are contaminants of emerging concern known for their persistence and recalcitrance to degradation due to the strength of their carbon-fluorine bonds. These chemicals have become a widespread water treatment challenge, as traditional water treatment approaches are ineffective at degrading most PFAS. Non-destructive techniques, such as adsorption on activated carbon and removal by reverse osmosis, are valuable tools but produce contaminated waste streams without destroying PFAS. Thus, there is a need to explore new approaches to degrade PFAS in water systems. Recently, many PFAS destruction techniques have utilized Advanced Oxidation Processes (AOPs), which generate short-lived and highly reactive species, particularly hydroxyl radical (HO•). However, multiple studies have shown that HO• is ineffective at initiating PFAS degradation. AOPs often produce many radicals besides HO• that require further investigation to elucidate their role in PFAS degradation. Here, we focus on perfluorooctanoic acid (PFOA), one of the most abundant and widely studied PFAS. This dissertation considers multiple radical-producing systems to obtain mechanistic insights into the role of superoxide radical (O2•–) and reactive chlorine radicals (generated by UV/chlorine systems) in PFOA degradation.