UV/H2O2 DEGRADATION OF E2 AND EE2 IN WATER EVALUATED VIA THE YES TOXICITY ASSAY

摘要

The transformation of the steroidal Endocrine Disrupting Compounds (EDCs), 17-β- estradiol (E2) and 17-α-ethinyl estradiol (EE2) by direct 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.