Removal of estrogenic activity of endocrine disrupting compounds in water with UV and UV/hydrogen peroxide advanced oxidation processes

Endocrine disrupting compounds (EDCs) are environmental contaminants that can interfere with hormone function, resulting in adverse effects on reproduction and development in organisms. UV and UV/advanced oxidation processes (AOP) have been considered as effective techniques for the oxidation and subsequent degradation of EDCs. Direct photolysis with two Hg UV lamps, monochromatic low pressure (LP)- and polychromatic medium pressure (MP)-UV irradiation, and UV/H2O2 AOP were used to assess the degradation of four EDCs including bisphenol A (BPA), 17-alpha-ethinyl estradiol (EE 2), 17-beta-estradiol (E2) or nonylphenol (NP) in water. Kinetics of UV and UV/AOP degradation of EDC parent compounds and formation of the degradation products were measured by high performance liquid chromatography (HPLC). Changes in estrogenic activity as a function of treatment were evaluated using both an in vitro yeast estrogen screen (YES) and in vivo vitellogenin (VTG) assay with Japanese medaka (Oryzias latipes) fish.; Results demonstrated that UV alone did not effectively degrade BPA; however, in combination with H2O2, UV doses relevant advanced oxidation processes used in water treatment significantly removed BPA parent compound and aqueous estrogenic activity in vitro and in vivo. Removal rates of in vivo estrogenic activity of BPA were significantly lower than those observed in vitro following UV/H2O2 AOP. Direct photolysis with MP-UV lamp was slightly more effective for removal of parent compound and in vitro estrogenic activity compared to LP-UV lamps; however, no significant difference in removal rates was found between the two lamps under UV+ H2O2 treatment. In addition, UV/H2O 2 AOP was effective for reducing medaka larval lethality in treated BPA solutions, suggesting BPA degradation products did not result in the production of acutely toxic intermediates in medaka larvae. However, in vivo and in vitro analyses suggest that certain UV/AOP metabolites may retain estrogenic activity.; Several water quality characteristics such as total organic carbon (TOC) and residual chlorine in natural water affected the expression of EE 2-estrogenic activity in vitro and in vivo. In addition, UV + H2O2 AOP was effective at removing in vitro and in vivo estrogenic activity in natural water including a mixture of EDCs (E2, EE 2, BPA and NP) at environmentally relevant concentrations.