Application of ionizing radiation for removal of endocrine disruptor bisphenol A from waters and wastewaters

The source of the residues of anthropogenic endocrine disruptor known as bisphenol A (BPA) in the natural environment and foods is both production and very wide use of several classes of polymers. Because of the documented inefficiency of BPA removal from waters and wastewaters using conventional treatment methods, several advanced oxidation processes (AOPs) employing hydroxyl radicals (radical (OH)-O-center dot) were developed for this purpose in the recent decade. In this work, especially efficient removal of BPA was performed with the use of radical (OH)-O-center dot radicals, which are formed from water radiolysis by irradiation with gamma-rays. For the initial BPA level 10 mg L-1 (43.9 mu M) the pseudo first order rate-constant for the reaction of radical center dot OH with BPA in neutral, aerated solutions was evaluated to be 0.392 min(-1) (6.23 kGy(-1)), which can be also much higher for lower initial BPA concentration. The possibility to predict the yield of radiolytic BPA decomposition based on Total Organic Carbon content of irradiated natural environmental samples was demonstrated. A detailed mechanism of radical reactions involving radical (OH)-O-center dot radicals and superoxide radical anions (O-2(center dot-)) was proposed leading to the formation of decomposition products which were identified by LC/MS analysis. Moreover, the changes in the cytotoxicity of gamma-irradiated BPA solutions were examined for two cell lines of human origin, namely liver carcinoma cells HepG2, and breast cancer cells MDA-MB-231.

Automated summary

BPA residues in the environment and food are mainly due to the production and widespread use of polymers, with conventional methods for removal being ineffective. Advanced oxidation processes utilizing hydroxyl radicals have shown promise in efficiently eliminating BPA. This study demonstrated that gamma ray-induced hydroxyl radicals can effectively remove BPA, and the yield of radiolytic BPA decomposition can be predicted based on the total organic carbon content of irradiated samples.