Perfluorooctanoic acid (PFOA) is a persisted organic pollutant and a common contaminant in wastewater because of its widespread occurrence in the environment and its ability to bioaccumulate. Recent studies indicate that PFOA is toxic and carcinogenic to animals such as rats, fishes, monkeys, and even humans. In this study, PFOA was decomposed in water using carbonate radical anions (CO3 center dot-) under 254 nm UV irradiation at 400 W. CO3 center dot- is a strong oxidizing and selective radical, however it works efficiently in decomposing PFOA solution. In this study, the results showed that PFOA was decomposed 100% after 12 h by using a combination of UV irradiation and CO3 center dot-, while under only UV irradiation, 52.1% of PFOA was decomposed. In addition, the decomposition of PFOA with CO3 center dot- under UV irradiation was more favorable in a slightly alkaline (pH = 8.8) solution and sodium hydrogen carbonate (NaHCO3) 40 mM. Moreover, the intermediates included the shorter-chain perfluorinated carboxylic acids and fluorine ions. (C) 2013 Elsevier B.V. All rights reserved.