Removal of dissolved estrogen in sewage effluents by β-cyclodextrin polymer

Substances with estrogenic activity are found in effluents of municipal sewage plants and dairy farms These effluents have the potential to induce feminization in male fish In this study cyclodextrin polymers (CDPs) that are insoluble in both polar and non-polar solvents were selected for the removal of dissolved estrogens in the effluent of a municipal sewage plant. The removal capacity of CDPs was high in the order of beta-CDP >= gamma-CDP >> alpha-CDP The mechanism for adsorption of estrogens to beta-CDP was not only due to a host-guest interaction as molecular recognition by beta-cyclodextrin (beta-CD) but also due to adsorption by the polymer matrix. beta-CDP of 0.2% (w/v) removed 17 beta-estradiol (E2) of about 70% from 10(-11) mol/L. and more than 90% from >= 10(-1) mol/L The removal ratios of E2 in the presence of cholesterols which are contained at higher concentrations than estrogens in sewage effluents and are adsorptive competitor for beta-CDP were about 85% at a cholesterol/E2 molar ratio of 100 and >90% at molar ratios of 0 1 1 and 10 The effluent from a municipal sewage plant had estrogenic activity corresponding to 5 5 x 10-11 molE2/L by yeast two-hybrid assay The estrogens in the effluent were also removed >90% by the beta-CDP treatment Therefore beta-CDP is able to remove dissolved estrogens over a wide range of concentrations in the presence of various contaminants such as wastewaters (C) 2010 Elsevier B V All rights reserved