Degradation of Endocrine Disrupting Chemicals Bisphenol A, Ethinyl Estradiol, and Estradiol during UV Photolysis and Advanced Oxidation Processes

TLDR

EDCs such as BPA, ethinyl estradiol, and estradiol are found at low concentrations in wastewaters and surface waters, can harm humans and wildlife via endocrine disruption, and conventional treatment often fails to remove them, necessitating alternative processes. The study investigated the degradation of BPA, ethinyl estradiol, and estradiol using UV photolysis and UV/H₂O₂ advanced oxidation. Quantum yields for direct UV photolysis were determined for both low‑pressure and medium‑pressure lamps, and second‑order rate constants for hydroxyl radical reactions were established. Using the derived parameters, the authors modeled UV treatment in laboratory and natural waters, finding that medium‑pressure UV photolysis outperformed low‑pressure lamps, yet UV/H₂O₂ advanced oxidation consistently achieved the highest degradation of the EDCs.

Abstract

The degradation of three endocrine disrupting chemicals (EDCs), bisphenol A, ethinyl estradiol, and estradiol, was investigated via ultraviolet (UV) radiation photolysis and the UV/hydrogen peroxide advanced oxidation process (AOP). These EDCs have been detected at low levels in wastewaters and surface waters in both the United States and European countries, can cause adverse effects on humans and wildlife via interactions with the endocrine system, and thus must be treated before entering the public drinking water supply. Because many EDCs can only be partially removed with conventional water treatment systems, there is a need to evaluate alternative treatment processes. For each EDC tested, direct UV photolysis quantum yields were derived for use with both monochromatic low-pressure (LP) UV lamps and polychromatic medium-pressure (MP) UV lamps and second-order hydroxyl radical rate constants were developed. These parameters were utilized to successfully model UV treatment of the EDCs in laboratory and natural waters. The polychromatic MP UV radiation source was more effective for direct photolysis degradation as compared to conventional LP UV lamps emitting monochromatic UV 254 nm radiation. However, in all cases the EDCs were more effectively degraded utilizing UV/H2O2 advanced oxidation as compared to direct UV photolysis treatment.