Removal of endocrine-disrupting chemical mixtures in water using chlorination and photolysis

Abstract

Micropollutants have been continuously detected in surface and groundwaters. In parallel, the potential adverse effects of human exposure to endocrine-disrupting chemicals (EDCs) through drinking water have been gaining the attention of researchers and health authorities. Given this fact, this study aimed to evaluate the effectivity of chlorination and photolysis to remove the estrogenic activity caused by mixtures of EDCs in water: estrone (E1: 100 ng L−1), 17β-estradiol (E2: 100 ng L−1), ethinylestradiol (EE2: 50 ng L−1), and nonylphenol (NP: 1,000 ng L−1) under operating conditions applicable for water treatment plants. The tests were performed using freshwater spiked with the following mixtures: E1 + E2, E1 + E2 + EE2, E1 + E2 + NP, and E1 + E2 + EE2 + NP). Removal efficiencies of up to 99.7% were achieved at a chlorine dose of 2.75 mg L–1 and 30 min of contact time. In photolysis, estrogenic activity removal was higher than 99.9% at a UV dose of 186 mJ cm–2. Results indicated that both chlorination and photolysis can be efficient to remove the estrogenic activity caused by the tested EDC mixtures in water. Furthermore, experiments suggested that EDC mixtures can be efficiently removed at feasible water disinfection operating conditions.