Electrochemical degradation of 17-alpha-ethinylestradiol (EE₂) and estrogenic activity changes

17-α-ethinylestradiol (EE₂) as one of typical representatives of steroid estrogens is detrimental to endocrine systems of animals and humans due to its potential estrogenic activity. The degradation of EE₂ in aquatic solution by electrocatalytic oxidation applying Ti-based SnO₂ (Ti/SnO₂) electrode as the anode was investigated. A pseudo-first-order kinetics under various initial concentrations of EE₂ was obtained and it was found that the calculated kinetic constant was determined as 0.112 min^-1, 0.053 min^-1, 0.023 min^-1 and 0.019 min^-1, which tended to rise in inverse proportion to EE₂ concentration within selected content of EE ₂ as 0.5 mg L^-1, 2.0 mg L^-1, 5 mg L ^-1 and 10 mg L^-1. Frozen recombinant yeast was introduced to evaluate estrogenic activities of an aqueous solution of 2.0 mg L ^-1 EE₂ and oxidation products. The concentration of EE₂ and EE₂ equivalents (EEEQs) decayed 96.5%, 96.3% respectively in 15 min and 78.5% reduction of TOC in 8 h was observed under current density conditions of 10 mA cm^-2 and 0.2 M Na ₂SO₄ as the electrolyte in the process of electrolysis. On the basis of the results obtained, it indicates that the estrogenic activities of the intermediate products can be negligible.