Adsorption and aerobic biodegradation of four selected endocrine disrupting chemicals in soil–water system

Abstract

Adsorption and aerobic biodegradation characteristics of four selected endocrine disrupting chemicals (EDCs), 17β-estradiol (E2), 17α-ethinylestradiol (EE2), bisphenol A (BPA) and nonylphenol (NP) were investigated in soil–water system. The sorption of EDCs onto the soil was in the following order: NP>E2>EE2>BPA. Sorption isotherms of the four compounds fitted Freundlich models well. The aerobic biodegradation rates of these selected EDCs in the soil–water system could be described by pseudo-first-order kinetic equation. In a single chemical system, the half-lives of EDCs were 1.7, 5.3, 2.7 and 3.3 d for E2, EE2, NP and BPA, respectively, indicating that EE2 was not as readily biodegradable as the others. In a binary-chemical system, the half-lives of EDCs in all cominations were 1.5–2.2 times prolonged than the single chemical system. The following biotransformation pathway of estrogen was proposed: E2/EE2→E1→E3. An aerobic conversion of EE2 to E3 was also observed. The result of this research could be useful for predicting environmental fate and ecological risks of EDCs in natural environments especially when soil is their depository.