AWWA WQTC64064

The transformation of the steroidal Endocrine Disrupting Compounds (EDCs), 17-ß- estradiol (E2) and 17-a-ethinyl estradiol (EE2) by direct ultraviolet (UV) photolysis and UV/H₂O₂ advanced oxidation was studied from the perspective of the removal of estrogenic activity associated with the compounds. First, experiments were performed to link the oxidation of E2 and EE2 with subsequent reduction in estrogenic activity. No statistically significant difference between these rates was observed, implying that the oxidation products of E2 and EE2 are not as estrogenic (as measured by the YES) as the parent compounds. Utilizing the YES, 90% removal of estrogenic activity of E2 and EE2 at environmentally relevant concentrations (~3µg L^-1) was achieved using a combination of 5 mg L^-1 H₂O₂ and a UV dose of less than 400 mJ cm^-2. Thus, these compounds, when considered at environmentally relevant levels, are significantly degraded at much lower UV doses than previously thought. A steady state OH radical model was used to predict oxidation of EE2 in the laboratory water. Includes 33 references, figures.